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1

SLIP SYSTEMS OF Cu2O BY KNOOP HARDNESS ANISOTROPY MEASUREMENT  

E-print Network

microhardness tests have been performed at room temperature on Cu2O cuprous oxide single crystals. Hardness. Microhardness tests are perform- ed using a Knoop indenter mounted in a Leitz mini- load hardness apparatus (1L-33 SLIP SYSTEMS OF Cu2O BY KNOOP HARDNESS ANISOTROPY MEASUREMENT A. AUDOUARD, B. PELLISSIER and J

Paris-Sud XI, Universit茅 de

2

Influence of placement techniques on Vickers and Knoop hardness of class II composite resin restorations  

Microsoft Academic Search

Objectives. To analyze the influence of two placement techniques on Knoop and Vickers hardness of class II cavities restored using packable (A.L.E.R.T., Solitaire 2, SureFil) and conventional microfilled and hybrid (Filtek A110 and Z250, respectively) resin composites.Methods. Fifty standardized class II cavities (5󫢩.5 mm3) were prepared in human premolars. They were divided into ten groups (n=5) and restored according to

Laiza T Poskus; Eliane Placido; Paulo E. Capel Cardoso

2004-01-01

3

Effects of potassium oxalate on knoop hardness of etch-and-rinse adhesives.  

PubMed

The objective of this study was to determine whether the hardness of etch-and-rinse adhesives may be affected by the pretreatment of acid-etched dentin with potassium oxalate desensitizer. Unerupted human third molars were cut into crown segments by removing the occlusal enamel and roots. The pulp chamber of these crown segments was connected to a syringe barrel filled with phosphate-buffered saline so that the moisture of dentin was maintained during the bonding procedures. Three etch-and-rinse adhesives-two two-step systems (Adper Single Bond 2 [SB], One-Step [OS]) and one three-step system (Adper Scotchbond Multi-Purpose [MP])-were applied to acid-etched dentin that had been treated (experimental groups) or not (control groups) with potassium oxalate (BisBlock). The Knoop hardness (KHN) of adhesives was taken at different sites of the outer surface of the adhesive-bonded dentin. The KHN of the three tested adhesives applied to acid-etched dentin treated with potassium oxalate was significantly lower than that exhibited by the respective controls (not treated with oxalate; p<0.05). Regardless of the adhesive, the treatment with potassium oxalate reduced the adhesives' KHN (p<0.05), with the OS system exhibiting the lowest KHN compared with the MP and SB systems. PMID:22335301

Silva, S M A; Malacarne-Zanon, J; Carvalho, R M; Alves, M C; De Goes, M F; Anido-Anido, A; Carrilho, M R

2012-01-01

4

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

NASA Astrophysics Data System (ADS)

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.

Nagakubo, A.; Ogi, H.; Sumiya, H.; Hirao, M.

2014-08-01

5

Impact of refrigeration on the surface hardness of hybrid and microfilled composite resins.  

PubMed

This in vitro study evaluated the Knoop hardness of the composite resins Charisma (C) and Durafill VS (D) polymerized in 3 different conditions: at room temperature (A) (23 +/- 1 degrees C); refrigerated at 4 +/- 1 degrees C and immediately photo-activated after removal from the refrigerator (0); and, refrigerated at 4 +/- 1 degrees C and photo-activated after a bench time of 15 min at room temperature (15). One hundred and twenty specimens (4 mm diameter and 2 mm depth) were made using a stainless steel mold and following manufacturer's instructions. All specimens were tested immediately after polymerization (I) and after 7 days of water storage in the dark at room temperature (7d). The data were subjected to ANOVA and post-hoc Tukey's test (alpha=0.05). On the top surface, C(AI) was statistically similar to C(15I) and D(AI) to D(15I) (p>0.05). On the bottom surface, C(AI) presented higher hardness values when compared to COI and C(15I) (p<0.05). The D groups showed no significant differences (p>0.05) on the bottom surfaces for any tested polymerization condition. After 7 days of storage, the Knoop hardness decreased significantly (p<0.05) for groups C(7d) and D(7d) except for C(07d), which was not different from C(OI) at either surface (p>0.05). D(07d) showed higher Knoop hardness (p<0.05) values on the top surface when compared to the other groups. PMID:19466230

Osternack, Fernando Henrique Ruppel; Caldas, Danilo Biazzetto de Menezes; Rached, Rodrigo Nunes; Vieira, S閞gio; Platt, Jeffrey A; Almeida, Janaina Bertoncelo de

2009-01-01

6

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

E-print Network

The fertilizing value of livestock waste is hardly determined considering its initial variability-products in Thai Binh The various observed states Livestock farmers' practices with regard to effluents management to transport. Manure is often used in this form by fish farmers, but it can also be treated. When

Paris-Sud XI, Universit茅 de

7

Test of a universality ansatz for the contact values of the radial distribution functions of hard-sphere mixtures near a hard wall  

E-print Network

Recent Monte Carlo simulation results for the contact values of polydisperse hard-sphere mixtures at a hard planar wall are considered in the light of a universality assumption made in approximate theoretical approaches. It is found that the data seem to fulfill the universality ansatz reasonably well, thus opening up the possibility of inferring properties of complicated systems from the study of simpler ones

Mariano Lopez de Haro; Santos B. Yuste; Andres Santos

2006-07-31

8

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

E-print Network

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

Hamel, Patrice

9

Hardness correlation for uranium and its alloys  

SciTech Connect

The hardness of 16 different uranium-titanium (U-Ti) alloys was measured on six (6) different hardness scales (R/sub A/, R/sub B/, R/sub C/, R/sub D/, Knoop, and Vickers). The alloys contained between 0.75 and 2.0 wt % Ti. All of the alloys were solutionized (850/sup 0/C, 1 h) and ice-water quenched to produce a supersaturated martensitic phase. A range of hardnesses was obtained by aging the samples for various times and temperatures. The correlation of various hardness scales was shown to be virtually identical to the hardness-scale correlation for steels. For more-accurate conversion from one hardness scale to another, least-squares-curve fits were determined for the various hardness-scale correlations. 34 figures, 5 tables.

Humphreys, D L; Romig, Jr, A D

1983-03-01

10

Chemical compositions and nutritional value of Asian hard clam (Meretrix lusoria) from the coast of Andaman Sea.  

PubMed

Chemical compositions and nutritive value of the edible portions including foot, mantle and viscera of Asian hard clam (Meretrix lusoria) harvested from the coast of Andaman Sea were determined. Proximate compositions varied with portions tested. Edible portions had moisture (76.23-84.22%) and protein (9.09-12.75%) as the major components. Carbohydrate (0.32-7.89%), fat (1.58-6.58%) and ash (1.23-2.58%) were also found at various levels, dependent upon portions. Myofibrillar proteins were observed as the major fraction in foot (40.54%) and mantle (31.65%), whilst non-protein nitrogen constituents were dominant in the viscera (36.85%). All portions contained a large amount of essential amino acids (167.66-187.63 mg/g sample), in which leucine (30.91-36.96 mg/g sample) and lysine (35.24-36.03 mg/g sample) were predominant. They were rich in polyunsaturated fatty acids (46.84-49.18% of total fatty acid) with high level of DHA (13.33-16.47 % of total fatty acids) and EPA (4.75-7.11% of total fatty acids). Cholesterol of 0.07-0.21% wet weight was detected. All portions were also rich in macro- (Na, K, Ca and Mg) and micro- (Fe, Zn, Cu and Cr) minerals. Therefore, Asian hard clam is an excellent source of several nutrients, which could be beneficial for the health of the consumers. PMID:23993597

Karnjanapratum, Supatra; Benjakul, Soottawat; Kishimura, Hideki; Tsai, Yung-Hsiang

2013-12-15

11

Comparison of CT-Number and Gray Scale Value of Different Dental Materials and Hard Tissues in CT and CBCT  

PubMed Central

Introduction: Computed tomography (CT) and cone-beam CT (CBCT) are valuable diagnostic aids for many clinical applications. This study was designed to compare the gray scale value (GSV) and Hounsfield unit (HU) of selected dental materials and various hard tissues using CT or CBCT. Methods and Materials: Three samples of all test materials including amalgam (AM), composite resin (CR), glass ionomer (GI), zinc-oxide eugenol (ZOE), calcium-enriched mixture (CEM) cement, AH-26 root canal sealer (AH-26), gutta-percha (GP), Coltosol (Col), Dycal (DL), mineral trioxide aggregate (MTA), zinc phosphate (ZP), and polycarbonate cement (PC) were prepared and scanned together with samples of bone, dentin and enamel using two CBCT devices, Scanora 3D (S3D) and NewTom VGi (NTV) and a spiral CT (SCT) scanner (Somatom Emotion 16 multislice spiral CT);. Subsequently, the HU and GSV values were determined and evaluated. The data were analyzed by the Kruskal-Wallis and Mann-Whitney U tests. The level of significance was determined at 0.05. Results: There were significant differences among the three different scanners (P<0.05). The differences between HU/GSV values of 12 selected dental materials using NTV was significant (P<0.05) and for S3D and SCT was insignificant (P>0.05). All tested materials showed maximum values in S3D and SCT (3094 and 3071, respectively); however, bone and dentin showed low/medium values (P<0.05). In contrast, the tested materials and tissues showed a range of values in NTV (366 to15383; P<0.05). Conclusion: Scanner system can influence the obtained HU/GSV of dental materials. NTV can discriminate various dental materials, in contrast to S3D/SCT scanners. NTV may be a more useful diagnostic aid for clinical practice. PMID:25386210

Emadi, Naghmeh; Safi, Yaser; Akbarzadeh Bagheban, Alireza; Asgary, Saeed

2014-01-01

12

Be hard on the interests and soft on the values: conflict issue moderates the effects of anger in negotiations.  

PubMed

Emotions play an important role in conflict resolution. Past work has found that negotiators tend to concede when confronted with anger. We argue and show that this effect occurs in conflicts about interests, but not in conflicts about values. In value conflicts that are more closely tied to a person's values, norms, and identity, expressions of anger are likely to backfire. We demonstrate that people deem expressions of anger more unfair in value conflicts than in interest conflicts (Study 1) and that they are more likely to engage in retaliatory and escalatory behaviours when confronted with an angry reaction in the context of a value issue rather than an interest issue (Study 2). PMID:22283784

Harinck, Fieke; Van Kleef, Gerben A

2012-12-01

13

Hybrid hard- and soft-modeling of spectrophotometric data for monitoring of ciprofloxacin and its main photodegradation products at different pH values  

NASA Astrophysics Data System (ADS)

A simple and fast on line spectrophotometric method combined with a hybrid hard-soft modeling multivariate curve resolution (HS-MCR) was proposed for the monitoring of photodegradation reaction of ciprofloxacin under UV radiation. The studied conditions attempt to emulate the effect of sunlight on these antibiotics that could be eventually present in the environment. The continuous flow system made it possible to study the ciprofloxacin degradation at different pH values almost at real time, avoiding errors that could arise from typical batch monitoring of the reaction. On the base of a concentration profiles obtained by previous pure soft-modeling approach, reaction pathways have been proposed for the parent compound and its photoproducts at different pH values. These kinetic models were used as a constraint in the HS-MCR analysis. The kinetic profiles and the corresponding pure response profile (UV-Vis spectra) of ciprofloxacin and its main degradation products were recovered after the application of HS-MCR analysis to the spectra recorded throughout the reaction. The observed behavior showed a good agreement with the photodegradation studies reported in the bibliography. Accordingly, the photodegradation reaction was studied by high performance liquid chromatography coupled with UV-Vis diode array detector (HPLC-DAD). The spectra recorded during the chromatographic analysis present a good correlation with the ones recovered by UV-Vis/HS-MCR method.

Razuc, Mariela; Garrido, Mariano; Caro, Yamile S.; Teglia, Carla M.; Goicoechea, H閏tor C.; Fern醤dez Band, Beatriz S.

2013-04-01

14

Hybrid hard- and soft-modeling of spectrophotometric data for monitoring of ciprofloxacin and its main photodegradation products at different pH values.  

PubMed

A simple and fast on line spectrophotometric method combined with a hybrid hard-soft modeling multivariate curve resolution (HS-MCR) was proposed for the monitoring of photodegradation reaction of ciprofloxacin under UV radiation. The studied conditions attempt to emulate the effect of sunlight on these antibiotics that could be eventually present in the environment. The continuous flow system made it possible to study the ciprofloxacin degradation at different pH values almost at real time, avoiding errors that could arise from typical batch monitoring of the reaction. On the base of a concentration profiles obtained by previous pure soft-modeling approach, reaction pathways have been proposed for the parent compound and its photoproducts at different pH values. These kinetic models were used as a constraint in the HS-MCR analysis. The kinetic profiles and the corresponding pure response profile (UV-Vis spectra) of ciprofloxacin and its main degradation products were recovered after the application of HS-MCR analysis to the spectra recorded throughout the reaction. The observed behavior showed a good agreement with the photodegradation studies reported in the bibliography. Accordingly, the photodegradation reaction was studied by high performance liquid chromatography coupled with UV-Vis diode array detector (HPLC-DAD). The spectra recorded during the chromatographic analysis present a good correlation with the ones recovered by UV-Vis/HS-MCR method. PMID:23376269

Razuc, Mariela; Garrido, Mariano; Caro, Yamile S; Teglia, Carla M; Goicoechea, H閏tor C; Fern醤dez Band, Beatriz S

2013-04-01

15

Young's modulus and fracture during Knoop indentation of potassium, rubidium, cesium, and ammonium acid phthalate single crystals on the (010) plane  

NASA Astrophysics Data System (ADS)

The correlation of the anisotropy of the Young's modulus of organic single crystals of potassium, rubidium, cesium, and ammonium acid phthalates with strain and fracture patterns during Knoop indentation on the (010) cleavage plane in the [001] and [100] directions has been studied. The data on the maximum anisotropy of the strain and fracture patterns of the ammonium acid phthalate single crystal have been discussed in view of the published data on the structure, mechanical, elastic, and X-ray spectral properties of these crystals.

Sizova, N. L.; Moiseeva, N. A.

2012-12-01

16

Microindentation hardness evaluation of iridium alloy clad vent set cups  

SciTech Connect

An iridium alloy, DOP-26, is used as cladding for {sup 238}PuO{sup 2} fuel in radioisotope heat sources for space power systems. Presently, DOP-26 iridium alloy clad vent sets (CVS) are being manufactured at the Oak Ridge Y-12 Plant for potential use in the National Aeronautics and Space Administration`s Cassini mission to Saturn. Wrought/ground/stress relieved blanks are warm formed into CVS cups. These cups are then annealed to recrystallize the material for subsequent fabrication/assembly operations as well as for final use. One of the cup manufacturing certification requirements is to test for Vickers microindentation hardness. New microindentation hardness specification limits, 210 to 310 HV, have been established for a test load of 1000 grams-force (gf). The original specification limits, 250 to 350 HV, were for 200 gf testing. The primary reason for switching to a higher test load was to reduce variability in the test data. The DOP-26 alloy exhibits microindentation hardness load dependence, therefore, new limits were needed for 1000 gf testing. The new limits were established by testing material from 15 CVS cups using 200 gf and 1000 gf loads and then statistically analyzing the data. Additional work using a Knoop indenter and a 10 gf load indicated that the DOP-26 alloy grain boundaries have higher hardnesses than the grain interiors.

Ulrich, G.B.; DeRoos, L.F.; Stinnette, S.E.

1992-05-15

17

Microindentation hardness evaluation of iridium alloy clad vent set cups  

SciTech Connect

An iridium alloy, DOP-26, is used as cladding for {sup 238}PuO{sup 2} fuel in radioisotope heat sources for space power systems. Presently, DOP-26 iridium alloy clad vent sets (CVS) are being manufactured at the Oak Ridge Y-12 Plant for potential use in the National Aeronautics and Space Administration's Cassini mission to Saturn. Wrought/ground/stress relieved blanks are warm formed into CVS cups. These cups are then annealed to recrystallize the material for subsequent fabrication/assembly operations as well as for final use. One of the cup manufacturing certification requirements is to test for Vickers microindentation hardness. New microindentation hardness specification limits, 210 to 310 HV, have been established for a test load of 1000 grams-force (gf). The original specification limits, 250 to 350 HV, were for 200 gf testing. The primary reason for switching to a higher test load was to reduce variability in the test data. The DOP-26 alloy exhibits microindentation hardness load dependence, therefore, new limits were needed for 1000 gf testing. The new limits were established by testing material from 15 CVS cups using 200 gf and 1000 gf loads and then statistically analyzing the data. Additional work using a Knoop indenter and a 10 gf load indicated that the DOP-26 alloy grain boundaries have higher hardnesses than the grain interiors.

Ulrich, G.B.; DeRoos, L.F.; Stinnette, S.E.

1992-05-15

18

Generating Hard Satisfiability Problems  

Microsoft Academic Search

We report results from large-scale experiments in satisfiability testing. As has been observed by others, testing the satisfiability of random formulas often appears surprisingly easy. Here we show that by using the right distribution of instances, and appropriate parameter valu es, it is possible to generate random formulas that are hard, that is, for which satisfiability testing is quite difficult.

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

1996-01-01

19

Instrumented hardness testing using a flat punch  

Microsoft Academic Search

Instrumented hardness tests using a flat punch were performed and analysed using an original approach. The quality of the hardness-flow stress correlation using this particular type of indenter is investigated. It is found that some characteristic force values of the instrumented hardness test are very well correlated to yield and tensile strength.

M. Scibetta; E. Lucon; R. Chaouadi; E. van Walle

2003-01-01

20

Confined Hard Disk System Model  

NSDL National Science Digital Library

The Confined Hard Disk System is an idealized statistical mechanics model that simulates a two-dimensional system of hard disks confined to a box with a constant temperature thermal reservoir at one end and a movable piston at the other. Slow-moving particles are color-coded as blue and fast particles are color-coded as yellow. The model computes and plots the time evolution of the kinetic energy K per particle, the pressure P, and聽the volume V. The model also displays histograms and mean values of these quantities. The Confined Hard Disk System was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_stp_hd_ConfinedHardDiskSystem.jar file will run the program if Java is installed.

Christian, Wolfgang

2010-12-27

21

STP Hard Disks Metropolis Program  

NSDL National Science Digital Library

The STP Hard Disks Metropolis program is a Monte Carlo simulation of hard disks in two dimensions. The default initial condition is a rectangular configuration of N=64 particles in a box of length L = 40. You can slowly increase the density of the gas (by setting the minimum scale length between centers to a value slightly less than 1) to explore phase transitions. STP HardDisksMetropolis is part of a suite of Open Source Physics programs that model aspects of Statistical and Thermal Physics (STP). The program is distributed as a ready-to-run (compiled) Java archive. Double-clicking the stp_HardDisksMetropolis.jar file will run the program if Java is installed on your computer. Additional programs can be found by searching ComPADRE for Open Source Physics, STP, or Statistical and Thermal Physics.

Gould, Harvey; Tobochnik, Jan; Christian, Wolfgang; Cox, Anne

2009-03-06

22

Hard arc-sprayed coating with enhanced erosion and abrasion wear resistance  

NASA Astrophysics Data System (ADS)

A cored wire formulation, referred to as Alpha 1800, has been developed to produce tailored arc-sprayed coatings that are tough enough to resist particle impacts at 90 and sufficiently hard to deflect eroding particles at low impact angles. One millimeter thick coatings composed of ductile and hard phases with a Knoop hardness reaching 1800 kg/mm2 were easily produced by arc spraying the cored wire with air. Coatings were (1) erosion tested at 25 癈 and higher temperatures at impact angles of 25 and 90 in a gasblast erosion rig, (2) slurry erosion tested at impact angles of 25 and 90, and (3) abrasion wear tested using the ASTM G-65 test procedure. Results show that coatings produced with the new cored wire are at least 5 times more erosion resistant and 10 times more abrasion resistant than coatings produced by arc spraying commercial cored wires. The performance of the new arc-sprayed coating can be compared with that of high-energy WC-based coatings. Maintaining their erosion resistance after being exposed to temperatures up to 850 癈 and possessing good oxidation resistance, arc-sprayed coatings produced with the new cored wire are attractive for applications in many industrial sectors involving high temperatures.

Dallaire, S.

2001-09-01

23

Wear of hard materials by hard particles  

SciTech Connect

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.

Hawk, Jeffrey A.

2003-10-01

24

Hardness testing. 2nd edition  

SciTech Connect

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.

Chandler, H. [ed.

1999-07-01

25

On the indentation recovery and fleeting hardness of polymers  

E-print Network

On the indentation recovery and fleeting hardness of polymers Catherine A. Tweedie and Krystyn J and volume within 48 h. This viscoelastic response demonstrates that indentation hardness values indentation hardness does not quantitatively or qualitatively predict recoverable work or residual deformation

Van Vliet, Krystyn J.

26

DEFINITION OF NEW INDUSTRIAL HARDNESS TEST USING EQUIVALENT INDENTATION DEPTH  

Microsoft Academic Search

The Rockwell hardness test is commonly used and accepted by many industrial users, but the hardness value requires conversion between scales because the geometry of the indenters and the load ranges are different. On the other hand, hardness calculation using pyramidal indenters is quite simple and can be applied to any load range, though it is much more complicated to

Takashi Yamamoto; Kensuke Miyahara

27

How Hard is Chocolate?  

NSDL National Science Digital Library

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.

2007-12-20

28

Hardness of group IVA and IVB nitrides  

NASA Astrophysics Data System (ADS)

The hardnesses of various phases of group IVA and IVB nitrides (M3N4, M=C, Si, Ge, Sn, Ti, Zr or Hf; MN, M=Ti, Zr or Hf) were calculated using the bond electronegativity model for material hardness. The hardnesses of group IV nitrides increase with an increase in their average coordination numbers except for carbon nitrides, for which increasing the average coordination numbers results in a reduction in hardness. We suggest that for light-element compounds, the diamond-like structure represents the hardest one among all possible structures, whereas a high coordination number is generally required for heavy-element compounds to achieve high hardness values. This work provides a useful guide for designing novel nitride materials having excellent mechanical performances.

Li, Keyan; Xue, Dongfeng

2010-05-01

29

Session: Hard Rock Penetration  

SciTech Connect

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.

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

1992-01-01

30

Hardness Tester for Polyur  

NASA Technical Reports Server (NTRS)

Rubber-hardness tester modified for use on rigid polyurethane foam. Provides objective basis for evaluation of improvements in foam manufacturing and inspection. Typical acceptance criterion requires minimum hardness reading of 80 on modified tester. With adequate correlation tests, modified tester used to measure indirectly tensile and compressive strengths of foam.

Hauser, D. L.; Buras, D. F.; Corbin, J. M.

1987-01-01

31

Memory Hard Drive Peripherals  

E-print Network

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 搂 To provide a detailed

Stojmenovic, Ivan

32

Integrability versus non-integrability: hard hexagons and hard squares compared  

NASA Astrophysics Data System (ADS)

In this paper we compare the integrable hard hexagon model with the non-integrable hard squares model by means of partition function roots and transfer matrix eigenvalues. We consider partition functions for toroidal, cylindrical, and free杅ree boundary conditions up to sizes 40 40 and transfer matrices up to 30 sites. For all boundary conditions the hard squares roots are seen to lie in a bounded area of the complex fugacity plane along with the universal hard core line segment on the negative real fugacity axis. The density of roots on this line segment matches the derivative of the phase difference between the eigenvalues of largest (and equal) moduli and exhibits much greater structure than the corresponding density of hard hexagons. We also study the special point z=-1 of hard squares, where all eigenvalues have unit modulus, and we give several conjectures for the value at z=-1 of the partition functions.

Assis, M.; Jacobsen, J. L.; Jensen, I.; Maillard, J.-M.; McCoy, B. M.

2014-11-01

33

Integrability vs non-integrability: Hard hexagons and hard squares compared  

E-print Network

In this paper we compare the integrable hard hexagon model with the non-integrable hard squares model by means of partition function roots and transfer matrix eigenvalues. We consider partition functions for toroidal, cylindrical, and free-free boundary conditions up to sizes $40\\times40$ and transfer matrices up to 30 sites. For all boundary conditions the hard squares roots are seen to lie in a bounded area of the complex fugacity plane along with the universal hard core line segment on the negative real fugacity axis. The density of roots on this line segment matches the derivative of the phase difference between the eigenvalues of largest (and equal) moduli and exhibits much greater structure than the corresponding density of hard hexagons. We also study the special point $z=-1$ of hard squares where all eigenvalues have unit modulus, and we give several conjectures for the value at $z=-1$ of the partition functions.

M. Assis; J. L. Jacobsen; I. Jensen; J-M. Maillard; B. M. McCoy

2014-06-21

34

Point Defects in Hard Sphere Crystals  

E-print Network

We report numerical calculations of the concentration of interstitials in hard-sphere crystals. We find that, in a three-dimensional fcc hard-sphere crystal at the melting point, the concentration of interstitials is 2 * 10^-8. This is some three orders of magnitude lower than the concentration of vacancies. A simple, analytical estimate yields a value that is in fair agreement with the numerical results.

Sander Pronk; Daan Frenkel

2001-05-03

35

In Search of Colloidal Hard Spheres  

E-print Network

We recently reviewed the experimental determination of the volume fraction, $\\phi$, of hard-sphere colloids, and concluded that the absolute value of $\\phi$ was unlikely to be known to better than $\\pm 3$-6%. Here, in a second part to that review, we survey effects due to softness in the interparticle potential, which necessitates the use of an {\\em effective} volume fraction. We review current experimental systems, and conclude that the one that most closely approximates hard spheres remains polymethylmethacrylate spheres sterically stabilised by polyhydroxystearic acid `hairs'. For these particles their effective hard sphere diameter is around 1-10% larger than the core diameter, depending on the particle size. We argue that for larger colloids suitable for confocal microscopy, the effect of electrostatic charge cannot be neglected, so that mapping to hard spheres must be treated with caution.

C. Patrick Royall; Wilson C. K. Poon; Eric R. Weeks

2012-05-30

36

What Would You Work Hard For?  

NSDL National Science Digital Library

This lesson plan helps young children begin to learn about the concept of value and why some items are considered more valuable than others. These concepts relate to a geographical understanding of natural resources and the reasons why people work very hard to extract resources, such as during the California gold rush. This lesson has students go through a simulation to learn about value, abundance, and scarcity and asks them to consider the things that they would be willing to work very hard for.

37

Hard superconducting nitrides  

PubMed Central

Detailed study of the equation of state, elasticity, and hardness of selected superconducting transition-metal nitrides reveals interesting correlations among their physical properties. Both the bulk modulus and Vickers hardness are found to decrease with increasing zero-pressure volume in NbN, HfN, and ZrN. The computed elastic constants from first principles satisfy c11 > c12 > c44 for NbN, but c11 > c44 > c12 for HfN and ZrN, which are in good agreement with the neutron scattering data. The cubic ?-NbN superconducting phase possesses a bulk modulus of 348 GPa, comparable to that of cubic boron nitride, and a Vickers hardness of 20 GPa, which is close to sapphire. Theoretical calculations for NbN show that all elastic moduli increase monotonically with increasing pressure. These results suggest technological applications of such materials in extreme environments. PMID:15728352

Chen, Xiao-Jia; Struzhkin, Viktor V.; Wu, Zhigang; Somayazulu, Maddury; Qian, Jiang; Kung, Simon; Christensen, Axel N?rlund; Zhao, Yusheng; Cohen, Ronald E.; Mao, Ho-kwang; Hemley, Russell J.

2005-01-01

38

CSI: Hard Drive  

ERIC Educational Resources Information Center

Acting on information from students who reported seeing a classmate looking at inappropriate material on a school computer, school officials used forensics software to plunge the depths of the PC's hard drive, searching for evidence of improper activity. Images were found in a deleted Internet Explorer cache as well as deleted file space.

Sturgeon, Julie

2008-01-01

39

Hard Sphere Gas Model  

NSDL National Science Digital Library

The Ejs Hard Sphere Gas model displays a three-dimensional (ideal) gas made out of hard disks. Particles are initialized with a random speed and in a random direction and move with constant velocity until a collision occurs. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting 釵pen Ejs Model from the pop-up menu item. Ejs Hard Sphere Gas model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_newton_HardShpereGas.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for statistical mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang

2008-07-06

40

Hardness vs Randomness  

Microsoft Academic Search

We present a simple ne wc onstruction of a pseudorandom bit generator ,b ased on the constant depth generators of (N). It stretches a short string of truly random bits into a long string that looks random to an ya lgorithm from a comple xity class C (eg P, NC, PSPACE, ... )u sing an arbitrary function that is hard

Noam Nisan; Avi Wigderson

1994-01-01

41

Work Hard. Be Nice  

ERIC Educational Resources Information Center

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,

Mathews, Jay

2009-01-01

42

Hard Times Hit Schools  

ERIC Educational Resources Information Center

Hard-to-grasp dollar amounts are forcing real cuts in K-12 education at a time when the cost of fueling buses and providing school lunches is increasing and the demands of the federal No Child Left Behind Act still loom larger over states and districts. "One of the real challenges is to continue progress in light of the economy," said Gale Gaines,

McNeil, Michele

2008-01-01

43

On the hardness determination of fine grained concrete  

Microsoft Academic Search

Hardness tests of concretes are used, for the present, only for comparison, and the values of hardness obtained do not meet\\u000a the requirements of reproducibility. An attempt has been made to develop an experimental method which could measure accurately\\u000a the hardness characteristics of concrete and reproduce them. The most disseminated method, that of the steel ball indenter,\\u000a was used. The

M. KHOLMYANSKYt; E. Kogan; K. Kovler

1994-01-01

44

THEORY OF FLUX CREEP IN HARD SUPERCONDUCTORS  

Microsoft Academic Search

Previous investigations of the critical state of the hard superconductor ; have defined it in terms of constants alpha and B\\/sub O\\/; alpha (T) = J\\/sub cr\\/; (B\\/sub cr\\/ + B). If the current density J or the field B is increased ; beyond the critical values, a process called flux creep'' sets in, and flux ; leaks through the

P. Anderson

1962-01-01

45

Hard Copy Market Overview  

NASA Astrophysics Data System (ADS)

A number of Color Hard Copy (CHC) market drivers are currently indicating strong growth in the use of CHC technologies for the business graphics marketplace. These market drivers relate to product, software, color monitors and color copiers. The use of color in business graphics allows more information to be relayed than is normally the case in a monochrome format. The communicative powers of full-color computer generated output in the business graphics application area will continue to induce end users to desire and require color in their future applications. A number of color hard copy technologies will be utilized in the presentation graphics arena. Thermal transfer, ink jet, photographic and electrophotographic technologies are all expected to be utilized in the business graphics presentation application area in the future. Since the end of 1984, the availability of color application software packages has grown significantly. Sales revenue generated by business graphics software is expected to grow at a compound annual growth rate of just over 40 percent to 1990. Increased availability of packages to allow the integration of text and graphics is expected. Currently, the latest versions of page description languages such as Postscript, Interpress and DDL all support color output. The use of color monitors will also drive the demand for color hard copy in the business graphics market place. The availability of higher resolution screens is allowing color monitors to be easily used for both text and graphics applications in the office environment. During 1987, the sales of color monitors are expected to surpass the sales of monochrome monitors. Another major color hard copy market driver will be the color copier. In order to take advantage of the communications power of computer generated color output, multiple copies are required for distribution. Product introductions of a new generation of color copiers is now underway with additional introductions expected during 1987. The color hard copy market continues to be in a state of constant change, typical of any immature market. However, much of the change is positive. During 1985, the color hard copy market generated 1.2 billion. By 1990, total market revenue is expected to exceed 5.5 billion. The business graphics CHC application area is expected to grow at a compound annual growth rate greater than 40 percent to 1990.

Testan, Peter R.

1987-04-01

46

Valuing Essays: Essaying Values  

ERIC Educational Resources Information Center

The essay regularly comes under attack. It is criticised for being rigidly linear rather than flexible and reflective. I first challenge this view by examining reasons why the essay should be valued as an important genre. Secondly, I propose that in using the essay form students and academics necessarily exemplify their own critical values. Essays

Badley, Graham

2010-01-01

47

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.

2012-10-12

48

Hard metal composition  

DOEpatents

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.

Sheinberg, H.

1983-07-26

49

Hard physics in PHENIX  

E-print Network

We review recent results on hard observables in p+p, d+A and A+A collisions obtained by the PHENIX experiment. Emphasis is put on those measurements that provide insight into the properties of hot QCD media expected to be created in nucleus-nucleus collisions at RHIC energies. Direct photon spectra, jet properties and heavy quarks production measured in p+p and d+Au collisions are compared to the same observables extracted in heavy ion collisions to find modifications due to the presence of hot QCD matter.

D. Peressounko; for the PHENIX collaboration

2005-12-08

50

Hard Metal Disease  

PubMed Central

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

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

1962-01-01

51

Regularized 13 moment equations for hard spheres  

NASA Astrophysics Data System (ADS)

The regularized 13 moment equations (R13) of rarefied gas dynamics for a monatomic hard sphere gas in the linear regime are presented. The equations are based on an extended Grad-type moment system, which was systematically reduced by means of the Order of Magnitude Method [Struchtrup, Phys. Fluids 16(11), 3921-3934 (2004)]. The linear Burnett and super-Burnett equations are derived from Chapman-Enskog expansion of the R13 equations. While the Burnett coefficients agree with literature values, this seems to be the first time that super-Burnett coefficients are computed for a hard sphere gas. The equations are considered for stability, and dispersion and damping of sound waves. Boundary conditions are given, and solutions of simple boundary value problems are briefly discussed.

Struchtrup, Henning; Torrilhon, Manuel

2012-11-01

52

Exciting Hard Spheres  

E-print Network

We investigate the collision cascade that is generated by a single moving incident particle on a static hard-sphere gas. We argue that the number of moving particles at time t grows as t^{xi} and the number collisions up to time t grows as t^{eta}, with xi=2d/(d+2) and eta=2(d+1)/(d+2) and d the spatial dimension. These growth laws are the same as those from a hydrodynamic theory for the shock wave emanating from an explosion. Our predictions are verified by molecular dynamics simulations in d=1 and 2. For a particle incident on a static gas in a half-space, the resulting backsplatter ultimately contains almost all the initial energy.

T. Antal; P. L. Krapivsky; S. Redner

2008-05-25

53

Valued Constraint Satisfaction Problems: Hard and Easy Problems  

Microsoft Academic Search

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

Thomas Schiex; H閘鑞e Fargier; G閞ard Verfaillie

1995-01-01

54

Hard clam aquaculture is the largest and most valuable of the shellfish  

E-print Network

Hard clam aquaculture is the largest and most valuable of the shellfish aquaculture industries on the East Coast. It accounts for more than $50 million in economic value annually. Hard clams are bivalve or freshwater for an extend- ed period. Hard clams occur natural- ly all along the Atlantic coast from Nova

Florida, University of

55

A friction effect in low-load hardness testing of copper and aluminium  

Microsoft Academic Search

Vickers hardness tests were conducted on samples of copper and aluminium in a cold rolled or annealed condition to determine the apparent hardness variation in the load range 15 g to 20 kg. The variation was greatest for the soft specimens. Lubrication with an extreme-pressure lubricant was effective in reducing the hardness values to a virtually constant level for each

H. Shi; M. Atkinson

1990-01-01

56

Separating hard and soft scales in hard processes in a QCD plasma  

E-print Network

We present a picture of hard processes in a hot plasma in terms of the hard scale part of the process, where perturbative QCD should be applicable, and the soft scale part of the process, where we look to the AdS/CFT correspondence for guidance to possible strong effective coupling phenomena. In particular we estimate $\\hat{q}$, the transport coefficient, supposing that at soft scales partons in the plasma all cascade to small-$x$-values as indicated by strong coupling SYM theory.

A. H. Mueller

2008-05-20

57

Overview: Hard Rock Penetration  

SciTech Connect

The Hard Rock Penetration program is developing technology to reduce the costs of drilling and completing geothermal wells. Current projects include: lost circulation control, rock penetration mechanics, instrumentation, and industry/DOE cost shared projects of the Geothermal Drilling organization. Last year, a number of accomplishments were achieved in each of these areas. A new flow meter being developed to accurately measure drilling fluid outflow was tested extensively during Long Valley drilling. Results show that this meter is rugged, reliable, and can provide useful measurements of small differences in fluid inflow and outflow rates. By providing early indications of fluid gain or loss, improved control of blow-out and lost circulation problems during geothermal drilling can be expected. In the area of downhole tools for lost circulation control, the concept of a downhole injector for injecting a two-component, fast-setting cementitious mud was developed. DOE filed a patent application for this concept during FY 91. The design criteria for a high-temperature potassium, uranium, thorium logging tool featuring a downhole data storage computer were established, and a request for proposals was submitted to tool development companies. The fundamental theory of acoustic telemetry in drill strings was significantly advanced through field experimentation and analysis. A new understanding of energy loss mechanisms was developed.

Dunn, J.C.

1992-08-01

58

EVOLUTIONS IN HARDNESS SCALES DEFINITION  

Microsoft Academic Search

A conventional characteristic of hardness measurements is the strong dependency on the official definition of each scale. For this reason, and to assure a good connection between National Metrology Institutes (NMIs), scientific organizations (e.g., IMEKO1) and international organizations for standardization (e.g., ISO 2 and OIML 3 ), a new Working Group on Hardness (WGH) was created a few years ago

Giulio Barbato; Alessandro Germak; Konrad Herrmann; Samuel Low

59

Hard rock drilling problems explained by hard rock pressure plots  

SciTech Connect

Hard rock drilling problems are frustrating. Hard rock pore pressure interpretation is baffling. Because of slow drilling in hard streaks and absence of kicks (in overpressured shale sections), it is generally assumed pore pressures are close to ''normal'' over long depth intervals. Many hard rock drilling problems could not be logically explained, if this were the case. Nothing could be further from the truth. Hard rocks are difficult to drill because of the extreme zig-zags from overpressured shales to sub-normally pressured sands and carbonates. It is impossible to drill anywhere near balanced in both situations, simultaneously. Hard rock drilling problems caused by underbalance or overbalance (or both) are a result. But, a better understanding of the presence and magnitude of these pressure shifts will help minimize the worst extremes of imbalance and more intelligently strike an optimum compromise, realizing that mud density and, especially, mud chemistry can never completely solve these hard rock drilling problems. Well log pressure plots in these erratic stratigraphies are so difficult to interpret that they often have been considered useless. The example pore pressure plots shown here, including the Pressure Evaluation Profile (PEP) log -- a side by side comparison of several different pressure sensitive responses -- help interpret and explain many of these problems in a simple, logical manner.

Gill, J.A.

1983-02-01

60

Connectivity percolation in suspensions of hard platelets  

E-print Network

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.

Maneesh Mathew; Tanja Schilling; Martin Oettel

2012-04-13

61

Concept Mapping: Soft Science or Hard Art?  

NSDL National Science Digital Library

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.

Trochim, William

62

Feeding of the elliptic flow by hard partons  

NASA Astrophysics Data System (ADS)

We propose that in nuclear collisions at the LHC the elliptic flow may get a contribution from leading hard and semi-hard partons which deposit energy and momentum into the hydrodynamic bulk medium. The crucial effect is that these partons induce wakes which interact and merge if they come together. The contribution to the integrated elliptic flow is estimated with the help of a toy model to about 25% of the observed value and shows strong event-by-event fluctuations.

Tom釟ik, Boris; L関ai, P閠er

2011-09-01

63

Hard hadron spectroscopy  

E-print Network

I review lattice QCD calculations that compute the masses of the flavour singlet pseudoscalar mesons. I describe the progress in computing the mass spectrum of light 0++ mesons using lattice QCD. I also compare the results for basic quantities such as fpi and mrho, from various different formalisms of lattice QCD. I discuss the physical value of r0.

Craig McNeile

2007-10-04

64

Beta Backscatter Measures the Hardness of Rubber  

NASA Technical Reports Server (NTRS)

Nondestructive testing method determines hardness, on Shore scale, of room-temperature-vulcanizing silicone rubber. Measures backscattered beta particles; backscattered radiation count directly proportional to Shore hardness. Test set calibrated with specimen, Shore hardness known from mechanical durometer test. Specimen of unknown hardness tested, and radiation count recorded. Count compared with known sample to find Shore hardness of unknown.

Morrissey, E. T.; Roje, F. N.

1986-01-01

65

Effects of differences in hardness measurement procedures on the traceability chain and calibration process  

NASA Astrophysics Data System (ADS)

Establishment of traceability in hardness measurement is still under discussion at the ISO TC 164 SC 3 subcommittee on hardness testing. Two paths for establishing traceability are proposed for the Rockwell hardness measurement in ISO 6508-1. One way is taking a route to SI units through direct calibration of machine components, and the other way is taking a route to a hardness measurement standard through indirect calibration of machine performance. In addition to this, the difference in hardness measurement procedures between Rockwell and Brinell/Vickers hardness causes further confusion in establishing a traceability chain and an uncertainty evaluation process. This confusion is partly caused by the characteristics of hardness value, i.e. a procedure-dependent property. In this paper, methods used for the establishment of traceability for Rockwell, Brinell and Vickers hardness measurements are discussed based on the concept defined in the VIM.

Tak, Nae Hyung; Moo Lee, Hae; Bahng, Gunwoong

2013-06-01

66

Ejs Hard Disk Gas Model  

NSDL National Science Digital Library

The Ejs Hard Disk Gas model displays a two-dimensional gas made out of hard disks. Particles are initialized with a speed v=1 in a random direction and move with constant velocity until a collision occurs. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting 釵pen Ejs Model from the pop-up menu item. Ejs Hard Disk Gas model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_newton_HardDiskGas.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for statistical mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang

2008-07-06

67

HARD CLAM HYBRIDS FOR FLORIDAAQUACULTURE: HATCHERY CULTURE  

E-print Network

HARD CLAM HYBRIDS FOR FLORIDAAQUACULTURE: HATCHERY CULTURE John Scarpa: Harbor Branch Oceanographic and Aquatic Sciences, Gainesville, FL 32653 Introduction The hard clam (Mercenaria mercenaria notata summers of Florida. Southern hard clams, Mercenaria campechiensis, may have production traits

Florida, University of

68

Easy Problems are Sometimes Hard  

Microsoft Academic Search

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

Ian P. Gent; Toby Walsh

1994-01-01

69

Elastic\\/plastic effects during very low-load hardness testing of copper  

Microsoft Academic Search

A nanoindentation test system has been applied to obtaining continuous low-load\\/penetration depth results on a reference copper material. As usual, higher apparent hardness values occur at the lowest load values. An explanation is given in terms of the elastic load bearing capacity of the material. The analysis leads to a proposed hardness stress\\/strain description that appears to be satisfactory.

R. W. Armstrong; H. Shin; A. W. Ruff

1995-01-01

70

The hard truth  

SciTech Connect

In the Bayesian methodology, the posterior probability combines uncertainty about prior knowledge, and available data about alternative models of reality. The posterior quantifies the degree of certainty one has in inferring the truth in terms of those models. We propose a method to determine the reliability of a specific feature of a Bayesian solution. Our approach is based on an analogy between the negative logarithm of the posterior and a physical potential. This analogy leads to the interpretation of gradient of this potential as a force that acts on the model. As model parameters are perturbed from their maximum a posteriori (MAP) values, the strength of the restoring force that drives them back to the MAP solution is directly related to the reliability of those parameter estimates. The correlations between the uncertainties of parameter estimates can be elucidated.

Hanson, K.M.; Cunningham, C.S.

1994-12-31

71

30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2012 CFR

...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2012-07-01

72

30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2011 CFR

...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2011-07-01

73

30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2011 CFR

...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2011-07-01

74

30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2012 CFR

...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2012-07-01

75

30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2013 CFR

...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2013-07-01

76

30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2010 CFR

...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2010-07-01

77

30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2010 CFR

...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2010-07-01

78

30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2013 CFR

...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2013-07-01

79

Expected Value  

NSDL National Science Digital Library

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.

Siegrist, Kyle

2008-12-24

80

Hard Hat Use and Inspection Hard hats are an important piece of personal protective equipment (PPE). Hard hats worn  

E-print Network

Hard Hat Use and Inspection Hard hats are an important piece of personal protective equipment (PPE). Hard hats worn at Berkeley Lab must comply with the requirements of ANSI Z89.1 for impact protection follow manufacturer's recommendations for specific inspection procedures. Hard Hat Inspection - Bullard

Eisen, Michael

81

Hard diffraction -- 20 years later  

E-print Network

The idea of diffractive processes with a hard scale involved, to resolve the underlying parton dynamics, was published 1985 and experimentally verified 1988. Today hard diffraction is an active research field with high-quality data and new theoretical models. The trend from Regge-based pomeron models to QCD-based parton level models has given insights on QCD dynamics involving perturbative gluon exchange mechanisms, including the predicted BFKL-dynamics, as well as novel ideas on non-perturbative colour fields and their interactions. Extrapolations to the LHC include the interesting possibility of diffractive Higgs production.

Gunnar Ingelman

2005-12-12

82

STUDY OF THE BEST MEASUREMENT CAPABILITY IN ROCKWELL SCALE AT THE BRAZILIAN NMI INMETROS PRIMARY HARDNESS STANDARD MACHINE  

Microsoft Academic Search

This paper shows the actual status of an on- going metrological research that aims an upgrade of the current Rockwell C hardness scales best measurement capability (BMC), e.g. 0.3 HRC, referred to the Primary Hardness Standard Machine installed at the Brazilian NMI INMETRO. This value complies with the ISO hardness standards and the GUM uncertainty guide as well as the

Jorge Trota Filho; S閞gio Pinheiro de Oliveira; Islei Domingues da Silva; Renato Reis Machado; Cl醬dio Afonso Koch

83

Hard Trying and These Recipes  

ERIC Educational Resources Information Center

Writers thrive when they are motivated to work hard, have regular opportunities to practice and reflect, and benefit from a knowledgeable teacher who knows writing. Student feedback to lessons during writing workshop helped guide Nancie Atwell in her quest to provide the richest and most efficient path to better writing.

Atwell, Nancie

2003-01-01

84

Indentation hardness testing of rock  

Microsoft Academic Search

The indentation testing was used for characterisation of hardness of rock materials. During the test, an indentor under applied load penetrated into the rock surface forming a crater. The testing procedure was developed to be in line with other ISRM Suggested Methods. The results show that standardised indentation testing allows for characterisation of mechanical properties of rock and that there

T Szwedzicki

1998-01-01

85

TESTING HARDNESS OF METAL ITEMS WITH MET-UD COMBINED PORTABLE HARDNESS TESTER  

Microsoft Academic Search

A new approach to portable hardness testers has been developed and introduced. It makes it possible to inspect hardness by one and the same hardness tester applying both, the ultrasonic contact impedance method and rebound method. Hardness tester wide possibilities which allow to inspect hardness of metal and alloy products with all standardized scales (Rockwell, Brinell, Vickers and Shore) have

Edward Aslanyan; Alexander Doynikov; Victor Pivovarov

86

Effect of hardness on acute toxicity of metal mixtures using Daphnia magna: Prediction of acid mine drainage toxicity  

Microsoft Academic Search

In this study, the effect of hardness on the combined outcome of metal mixtures was investigated using Daphnia magna. The toxic unit (TU) was calculated using modified LC50 values based on the hardness (i.e., LC50-soft and LC50-hard). From a bioassay test, the degree of sensitivity to hardness on the toxicity changes was in the order: Cd

Jin Hee Yim; Kyoung W. Kim; Sang D. Kim

2006-01-01

87

An energy-balance analysis for the size effect in low-load hardness testing  

Microsoft Academic Search

The size effect in low-load hardness testing is analyzed theoretically using an energy-balance approach. A new semi-empirical equation is proposed to correlate the hardness test load and the resulting indentation size. The validity of this new equation is verified by analyzing the previously reported experimental data. It is found that the value of true hardness of material estimated with this

Jianghong Gong; Ying Li

2000-01-01

88

Solar cell nanotechnology for improved efficiency and radiation hardness  

Microsoft Academic Search

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

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

2006-01-01

89

Thermodynamic properties of lattice hard-sphere models  

Microsoft Academic Search

Thermodynamic properties of several lattice hard-sphere models were obtained from grand canonical histogram- reweighting Monte Carlo simulations. Sphere centers occupy positions on a simple cubic lattice of unit spacing and exclude neighboring sites up to a distance ?. The nearestneighbor exclusion model, ?=&sqrt;2, was previously found to have a second-order transition. Models with integer values of ?=1 or 2 do

A. Z. Panagiotopoulos

2005-01-01

90

Evaluation of mechanical properties of some glycine complexes  

NASA Astrophysics Data System (ADS)

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.

Nagaraju, D.; Raja Shekar, P. V.; Chandra, Ch. Sateesh; Rao, K. Kishan; Krishna, N. Gopi

2014-04-01

91

Collision statistics in sheared inelastic hard spheres  

E-print Network

The dynamics of sheared inelastic-hard-sphere systems are studied using non-equilibrium 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 more direct, head-on collisions. Examination of the distribution of the time 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 DSMC simulation of the Enskog equation. Results of the kinetic model of Montanero et al. {[}Montanero et al., 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.

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

2009-03-24

92

Piezoelectric properties in soft-hard pseudobinary system  

Microsoft Academic Search

Pb(Zr, Ti)O3 Ceramics added with Pb(Sb1\\/2Nb1\\/2)O3 (PSN) or Pb(Mn1\\/3Nb2\\/3)O3 (PMN) ceramics behave like soft and hard piezoelectric materials, respectively. Variety in piezoelectric properties is obtained in the pseudobinary system constituted by PZT-PSN and PZT-PMN ceramics. Compositions having both high Kp and Qm values are prepared. An enhancement in piezoelectric activity is found when the composition is rich in hard material

Syh-Yuh Cheng; Chien-Min Wang; Shu-Fen Liao

1990-01-01

93

Hard Photodisintegration of 3He  

NASA Astrophysics Data System (ADS)

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.

Granados, Carlos

2011-02-01

94

Ultrasonic material hardness depth measurement  

DOEpatents

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.

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

1997-07-08

95

Weld cladding of hard surfaces  

NASA Astrophysics Data System (ADS)

A literature study about clad welding of hard surfaces on steel is performed. The purpose was to see what kind of methods are mainly used, and particular attention is paid to clad welding of rolls. The main impression from this study is that several methods are in use. Some of these must be considered as 'too exotic' for the aim of the program, such as laser build-up welding. However, clad welding of hard surfaces to rolls is widely used around the world, and there is no need for particularly advanced welding methods to perform the work. The welding consumables and the way the welding is carried out is of more important character. The report will give some comments to this, and hopefully will give a short review of the current technology in this field.

Habrekke, T.

1993-02-01

96

Surface hardness enhancement in ion-implanted amorphous carbon D. H. Lee and B. Parka)  

E-print Network

and ion doses. The apparent surface hardness measured by nanoindentation with load-displacement data shows/cm3 , less than the value of single-crystal graphite, but higher than the density of normal amorphous simulation fitting. A Nanoindenter from Nano Instruments, Inc. was used for surface hardness measurements

Park, Byungwoo

97

Quantitative Trait Loci Associated with Milling and Baking Quality in a Soft Hard Wheat Cross  

Microsoft Academic Search

Hybridization between soft and hard wheat creates new associations among loci. Advantages include an increase Interclass hybridization between soft and hard wheat (Triticum in genetic diversity, a potential increase in grain yield, aestivum L.) results in new genetic combinations of potential value. and transfer of pest resistance genes. Both May et al. We investigated whether interclass hybridization could improve end-

Kimberly Garland Campbell; Patrick L. Finney; Christine J. Bergman; Daisy G. Gualberto; James A. Anderson; Michael J. Giroux; Dimuth Siritunga; Jiaqian Zhu; Francois Gendre; Catherine Rou; Aliette V閞el; Mark E. Sorrells

2001-01-01

98

Hard Disk PVT System Model  

NSDL National Science Digital Library

The Hard Disk PVT System simulates a two-dimensional system of particles confined between a thermal reservoir and a piston. This computer model is designed to study the equation of state for hard disks without other interactions. Slow-moving particles are color-coded as blue and fast particles are color-coded as yellow. Users can set the initial particle energy, the initial particle separation, and the thermal reservoir temperature Tr. The thermal conductivity parameter ? determines the probability that a collision with the thermal wall will affect (thermalize) the colliding particle. If the conductivity is one, the particle velocity after a reservoir collision is set according to Maxwell-Boltzmann statistics. If the conductivity is zero, all reservoir collisions are elastic and the internal energy E of the system is conserved. 聽 Particles in this model have unit mass and interact through contact forces. Collision times are computed analytically because particles and pistons move with constant velocity between collisions. The time evolution algorithm advances the particle and piston positions from collision to collision until the requested time step ?t is achieved. The time evolution is then paused, data is accumulated, and the screen is redrawn. The Hard Disk PVT model is a supplemental simulation for the article "Pressure Oscillations in Adiabatic Compression" by Roland Stout in The Physics Teacher 49(5), 280-281 (2011) and has been approved by the author and The Physics Teacher editor. The model was developed using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_stp_hd_HardDiskPVTSystem.jar file will run the program if Java is installed.

Christian, Wolfgang

2011-03-12

99

A Dynamic Hard Sphere Model  

Microsoft Academic Search

A simple two-dimensional model, in which uniform hard spheres are made to move steadily and apparently nearly at random, is described. At low sphere density the model exhibits ``gas-like'' behavior. As the density is increased the behavior becomes more ``liquid-like'' and then ``crystallization'' occurs. Many dynamic atomic phenomena, believed to occur in the gas, liquid, or solid state, are illustrated

D. Turnbull; R. L. Cormia

1960-01-01

100

Impact of aging on radiation hardness  

SciTech Connect

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.

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

1997-07-01

101

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 espa駉l: 縋or Qu ...

102

Using hardness to model yield and tensile strength  

SciTech Connect

The current direction in hardness research is towards smaller and smaller loads as nano-scale materials are developed. There remains, however, a need to investigate the mechanical behavior of complex alloys for severe environment service. In many instances this entails casting large ingots and making numerous tensile samples as the bounds of the operating environment are explored. It is possible to gain an understanding of the tensile strength of these alloys using room and elevated temperature hardness in conjunction with selected tensile tests. The approach outlined here has its roots in the work done by Tabor for metals and low alloy and carbon steels. This research seeks to extend the work to elevated temperatures for multi-phase, complex alloys. A review of the approach will be given after which the experimental data will be examined. In particular, the yield stress and tensile strength will be compared to their corresponding hardness based values.

Hawk, Jeffrey A.; Dogan, Omer N.; Schrems, Karol K.

2005-02-01

103

Determination of hardness and hardness penetration depth of metal components by Non Linear Harmonics Analysis  

NASA Astrophysics Data System (ADS)

For the characterization of steel quality, hardness is a very important parameter. The magneto-inductive Non Linear Harmonics Analysis (NLHA) has been developed and used as a non destructive technique for measuring core hardness, surface hardness and hardness penetration depth of steel components. A description of the working principle of NLHA is given together with the setup of a typical hardness measuring system. Examples are given for the determination of carbon content in steel foils, measurement of core hardness in gear bolts where the hardness was controlled by tempering. Further results demonstrate measurements of core hardness, surface hardness and hardness penetration depth of nitration hardened steel samples. The final example shows a hardness profile of a case hardened shaft.

Stegemann, D.; Reimche, W.; Feiste, K. L.; Reichert, Ch.; Marques-Fetter, P.

1999-12-01

104

DISTRIBUTED VERIFICATION AND HARDNESS OF DISTRIBUTED APPROXIMATION  

E-print Network

DISTRIBUTED VERIFICATION AND HARDNESS OF DISTRIBUTED APPROXIMATION ATISH DAS SARMA, STEPHAN HOLZER on the hardness of distributed approximation for many classical optimization problems including minimum spanning the previous hardness of approximation bound of Elkin [STOC 2004] as well as the lower bound for (exact) MST

105

Distributed Verification and Hardness of Distributed Approximation  

E-print Network

Distributed Verification and Hardness of Distributed Approximation Atish Das Sarma Google Foundation (BSF). Permission to make digital or hard copies of all or part of this work for personal on the hardness of distributed approxi- mation for many classical optimization problems including minimum spanning

106

Collisions of Nuclei: New Ideas for Hard  

E-print Network

Collisions of Nuclei: New Ideas for Hard Probes Rainer Fries Texas A&M University & RIKEN BNL collisions and hard probes Hadron chemistry and flavor conversions Tomography + development of a new test Equilibration, thermalization Quark Gluon Plasma Non-perturbative dynamics Hard particles (PT > 1 -2GeV): Rare

107

Artificially soft and hard surfaces in electromagnetics  

Microsoft Academic Search

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

Per-Simon Kildal

1990-01-01

108

Hardness of FeB4: Density functional theory investigation  

NASA Astrophysics Data System (ADS)

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).

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

2014-05-01

109

Polarization observables in hard rescattering mechanism of deuteron photodisintegration  

NASA Astrophysics Data System (ADS)

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.

Sargsian, Misak M.

2004-05-01

110

Hard body amphiphiles at a hard wall JOSEPH M. BRADER1y  

E-print Network

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

Ott, Albrecht

111

Hardness Standardization Our objective is to standardize and improve hardness measurement  

E-print Network

Hardness Standardization METALS Our objective is to standardize and improve hardness measurement both in the U.S. and internationally. NIST is the U.S. National Metrology Institute (NMI) for hardness, and as such, is responsible for traceability in hardness measurements. Objective Impact and Customers

112

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

E-print Network

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

Northern British Columbia, University of

113

The Hard Problem of Cooperation  

PubMed Central

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

Eriksson, Kimmo; Strimling, Pontus

2012-01-01

114

Hard Core entropy: lower bounds  

E-print Network

We establish lower bounds for the entropy of the Hard Core Model on a few 2d lattices $\\scriptstyle {\\rm {\\bf L}}.$ In this model the allowed configurations inside $\\scriptstyle \\{0,1\\}^{{\\rm {\\bf L}}}$ are the one's in which the nearest neighbor $\\scriptstyle 1$'s are forbidden. Our method which is based on a sequential fill-in scheme is unbiassed and thereby yields in principle arbitrarily good estimates for the topological entropy. The procedure also gives some detailed information on the support of the measure of maximal entropy.

Kari Eloranta

2009-07-23

115

Added values.  

PubMed

Values-based interviewing is an approach to recruitment that focuses on the job applicant's attitudes and behaviours and whether they are a good 'fit' for the organization.Used successfully by hospitals in the United States, the approach is being introduced to some NHS trusts. PMID:24734812

Trueland, Jennifer

116

Redeeming Value.  

ERIC Educational Resources Information Center

Presents an essay on organizational transformation and the way successful marketing transformations redeem a sense of value. Focuses on challenges faced by not-for-profit institutions, current changes in the library profession, and implications of the American Library Association's Goal 2000. A sidebar summarizes an interview with the director of

Whitwell, Stuart C. A.

1995-01-01

117

Place Value  

NSDL National Science Digital Library

The answers to these FAQ from the Teacher2Teacher service at The Math Forum @ Drexel contain many suggestions for providing students with practice on using place value skills. They include ideas contributed by T2T Associates and teacher participants. There are links to Ask Dr. Math resources, children's literature connections, and outside websites with related resources.

Math Forum, Teacher2Teacher FAQ; The Math Forum @ Drexel

2000-01-01

118

In vitro action of various carbamide peroxide gel bleaching agents on the micro hardness of human enamel  

PubMed Central

Aims and Objectives: The study was undertaken to evaluate the effects of different carbamide peroxide based gels on micro hardness of enamel exposed to these agents for a period of 8 h daily for a total of 1 week. Materials and Methods: Thirty enamel specimens of 5 5-mm dimensions were sectioned from labial surface of maxillary incisor teeth and were embedded in Bakelite. Each block is polished to facilitate micro hardness testing. Pre-bleaching hardness values of 30 samples were measured using Vickers micro hardness tester. After exposing the specimens for different agents for 8 h daily for 1 week, post-exposure micro hardness values were taken and evaluated. Conclusion: With increase in concentration of carbamide peroxide gel from 10% to 16%, mean micro hardness values decreased but to an insignificant level. PMID:22919222

Sunil, CH.R.; Sujana, V.; Choudary, T. Manisha; Nagesh, B.

2012-01-01

119

Probing Strangeness in Hard Processes  

E-print Network

Since the discovery of strangeness almost five decades ago, interest in this degree of freedom has grown up and now its investigation spans the scales from quarks to nuclei. Measurements with identified strange hadrons can provide important information on several hot topics in hadronic physics: the strange distribution and fragmentation functions, the nucleon tomography and quark orbital momentum, accessible through the study of the {\\it generalized} parton distribution and the {\\it transverse momentum dependent} parton distribution functions, the quark hadronization in the nuclear medium, the hadron spectroscopy and the search for exotic mesons. The CLAS12 large acceptance spectrometer in Hall B at the Jefferson Laboratory upgraded with a RICH detector together with the 12 GeV CEBAF high intensity, high polarized electron beam can open new possibilities to study strangeness in hard processes allowing breakthroughs in all those areas. This paper summarizes the physics case for a RICH detector for CLAS12. Many topics have been intensively discussed at the International Workshop "Probing Strangeness in Hard Processes" (PSHP2010) \\cite{PSHP-workshop} held in Frascati, Italy in October 2010. The authors of this papers like to thank all speakers and participants of the workshop for their contribution and very fruitful discussion.

H. Avakian; M. Battaglieri; E. Cisbani; M. Contalbrigo; U. D'Alesio; R. De Leo; R. Devita; P. Di Nezza; D. Hasch; V. Kubarovsky; M. Mirazita; M. Osipenko; L. Pappalardo; P. Rossi

2012-02-09

120

Hard and Soft Safety Verifications  

NASA Technical Reports Server (NTRS)

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.

Wetherholt, Jon; Anderson, Brenda

2012-01-01

121

Thermodynamic properties of lattice hard-sphere models  

Microsoft Academic Search

Thermodynamic properties of several lattice hard-sphere models were obtained from grand canonical histogram- reweighting Monte Carlo simulations. Sphere centers occupy positions on a simple cubic lattice of unit spacing and exclude neighboring sites up to a distance sigma. The nearestneighbor exclusion model, sigma=&surd;2, was previously found to have a second-order transition. Models with integer values of sigma=1 or 2 do

A. Z. Panagiotopoulos

2005-01-01

122

Probing Strangeness in Hard Processes  

E-print Network

Since the discovery of strangeness almost five decades ago, interest in this degree of freedom has grown up and now its investigation spans the scales from quarks to nuclei. Measurements with identified strange hadrons can provide important information on several hot topics in hadronic physics: the strange distribution and fragmentation functions, the nucleon tomography and quark orbital momentum, accessible through the study of the {\\it generalized} parton distribution and the {\\it transverse momentum dependent} parton distribution functions, the quark hadronization in the nuclear medium, the hadron spectroscopy and the search for exotic mesons. The CLAS12 large acceptance spectrometer in Hall B at the Jefferson Laboratory upgraded with a RICH detector together with the 12 GeV CEBAF high intensity, high polarized electron beam can open new possibilities to study strangeness in hard processes allowing breakthroughs in all those areas. This paper summarizes the physics case for a RICH detector for CLAS12. Many...

Avakian, H; Cisbani, E; Contalbrigo, M; D'Alesio, U; De Leo, R; Devita, R; Di Nezza, P; Hasch, D; Mirazita, M; Osipenko, M; Pappalardo, L; Rossi, P

2012-01-01

123

Hard-gapped Holographic Superconductors  

E-print Network

In this work we discuss the zero temperature limit of a "p-wave" holographic superconductor. The bulk description consists of a non-Abelian SU(2) gauge fields minimally coupled to gravity. We numerically construct the zero temperature solution which is the gravity dual of the superconducting ground state of the "p-wave" holographic superconductors. The solution is a smooth soliton with zero horizon size and shows an emergent conformal symmetry in the IR. We found the expected superconducting behavior. Using the near horizon analysis we show that the system has a "hard gap" for the relevant gauge field fluctuations. At zero temperature the real part of the conductivity is zero for an excitation frequency less than the gap frequency. This is in contrast with what has been observed in similar scalar- gravity-gauge systems (holographic superconductors). We also discuss the low but finite temperature behavior of our solution.

Pallab Basu; Jianyang He; Anindya Mukherjee; Hsien-Hang Shieh

2009-11-26

124

Analysis of hard carbon for lithium-ion batteries by hard X-ray photoelectron spectroscopy  

NASA Astrophysics Data System (ADS)

Non-graphitizable carbon (hard carbon) as a negative electrode material for lithium-ion batteries is investigated by X-ray photoelectron spectroscopy, and hard X-ray photoelectron spectroscopy (HX-PES). HX-PES spectra have peaks of both the solid electrolyte interphase on the hard carbon surface and the hard carbon itself. The change in spectrum with state of charge is observed by HX-PES. Hard carbon has two types of lithium insertion site; between graphene sheets and into nano-scale voids. These spectroscopic results are consistent with the lithium insertion mechanism into hard carbon.

Hori, Hironobu; Shikano, Masahiro; Kobayashi, Hironori; Koike, Shinji; Sakaebe, Hikari; Saito, Yoshiyasu; Tatsumi, Kuniaki; Yoshikawa, Hideki; Ikenaga, Eiji

2013-11-01

125

Toxicity of cadmium to early life stages of brown trout (Salmo trutta) at multiple water hardnesses.  

PubMed

Toxicity of cadmium to early life stages of brown trout (Salmo trutta) was determined at multiple water hardnesses. Increasing water hardness decreased cadmium toxicity. Postswimup fry were much more sensitive than embryos and larvae. Chronic values from early life stage tests initiated with eyed embryos were 3.52, 6.36, and 13.6 microg Cd/L at water hardnesses of 30.6, 71.3, and 149 mg/L, respectively. In tests initiated with 30-d postswimup fry, chronic values were 1.02, 1.83, and 6.54 microg Cd/L at water hardnesses of 29.2, 67.6, and 151 mg/L, respectively. Higher chronic values from the early life stage tests compared to tests initiated with swimup fry likely are caused by acclimation during cadmium-tolerant embryo and larval stages. Growth was not affected by cadmium in the early life stage tests but was negatively affected in tests initiated with fry at water hardnesses of 29.2 and 67.6 mg/L. Concentrations of cadmium that reduced growth were higher than those that increased mortality. Median lethal concentrations for swimup fry after 96 h were 1.23, 3.90, and 10.1 microg Cd/L at water hardnesses of 29.2, 67.6, and 151 mg/L, respectively. Test results enable prediction of acute mortality of brown trout swimup fry based on cadmium concentration and water hardness. PMID:17702340

Brinkman, Stephen F; Hansen, Daria L

2007-08-01

126

Erosion on abraded dental hard tissues by acid lozenges: an in situ study  

Microsoft Academic Search

The aim of this study was to analyse the erosive effect of acidic lozenges and to compare it with that of orange juice, known\\u000a to have the capacity to cause erosion. Two acidic, sugar-free lozenges and orange juice were tested in situ in nine patients.\\u000a Changes in surface Knoop microhardness and change in the surface texture were assessed. The results

Adrian Lussi; Peter Portmann; Beatrice Burhop

1998-01-01

127

Kinetics of hardness evolution during annealing of gamma-irradiated polycarbonate  

SciTech Connect

This study focuses on the evolution in microhardness values that accompany isothermal annealing in gamma-irradiated polycarbonate (PC). Hardness increases with increasing annealing time, temperature, and gamma radiation dose. A model composed of a mixture of first and zero order structure relaxation is proposed to interpret the hardness data. The rate constant data fit the Arrhenius equation, and the corresponding activation energy decreases with increasing dose. The extent of structural relaxation that controls the hardness in post-annealed PC increases with increasing annealing temperature and dose. The model demonstrates that hardness evolution in PC is an endothermic process. By contrast, when the model is applied to irradiated poly(methyl methacrylate) and hydroxyethyl methacrylate copolymer, hardness evolution is an exothermic process.

Yeh, S. H.; Chen, P. Y.; Lee, Sanboh [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Harmon, Julie [Department of Chemistry, University of South Florida, Tampa, Florida 33620-5250 (United States)

2012-12-01

128

Measurements of the hard-x-ray reflectivity of iridium  

SciTech Connect

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.

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

2007-01-10

129

Valuing vaccination  

PubMed Central

Vaccination has led to remarkable health gains over the last century. However, large coverage gaps remain, which will require significant financial resources and political will to address. In recent years, a compelling line of inquiry has established the economic benefits of health, at both the individual and aggregate levels. Most existing economic evaluations of particular health interventions fail to account for this new research, leading to potentially sizable undervaluation of those interventions. In line with this new research, we set forth a framework for conceptualizing the full benefits of vaccination, including avoided medical care costs, outcome-related productivity gains, behavior-related productivity gains, community health externalities, community economic externalities, and the value of risk reduction and pure health gains. We also review literature highlighting the magnitude of these sources of benefit for different vaccinations. Finally, we outline the steps that need to be taken to implement a broad-approach economic evaluation and discuss the implications of this work for research, policy, and resource allocation for vaccine development and delivery. PMID:25136129

Barnighausen, Till; Bloom, David E.; Cafiero-Fonseca, Elizabeth T.; O'Brien, Jennifer Carroll

2014-01-01

130

Predicting the Performance of Chain Saw Machines Based on Shore Scleroscope Hardness  

NASA Astrophysics Data System (ADS)

Shore hardness has been used to estimate several physical and mechanical properties of rocks over the last few decades. However, the number of researches correlating Shore hardness with rock cutting performance is quite limited. Also, rather limited researches have been carried out on predicting the performance of chain saw machines. This study differs from the previous investigations in the way that Shore hardness values (SH1, SH2, and deformation coefficient) are used to determine the field performance of chain saw machines. The measured Shore hardness values are correlated with the physical and mechanical properties of natural stone samples, cutting parameters (normal force, cutting force, and specific energy) obtained from linear cutting tests in unrelieved cutting mode, and areal net cutting rate of chain saw machines. Two empirical models developed previously are improved for the prediction of the areal net cutting rate of chain saw machines. The first model is based on a revised chain saw penetration index, which uses SH1, machine weight, and useful arm cutting depth as predictors. The second model is based on the power consumed for only cutting the stone, arm thickness, and specific energy as a function of the deformation coefficient. While cutting force has a strong relationship with Shore hardness values, the normal force has a weak or moderate correlation. Uniaxial compressive strength, Cerchar abrasivity index, and density can also be predicted by Shore hardness values.

Tumac, Deniz

2014-03-01

131

Phase diagram of hard tetrahedra.  

PubMed

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

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

2011-11-21

132

Effect of substrate hardness and film structure on indentation depth criteria for film hardness testing  

Microsoft Academic Search

The indentation depth limits for the Vickers microhardness testing of amorphous, polycrystalline, multilayer and single crystal coatings were investigated. The coating\\/substrate hardness ratio was varied in the range from 0.01 to 20. The critical indentation depth hc, below which the substrate has a negligible effect on the hardness, was estimated from the experimentally obtained hardness versus indentation depth curves. The

Ilze Manika; Janis Maniks

2008-01-01

133

Structure, preparation and properties of refractory compounds and systems (hard materials and hard metals)  

NASA Technical Reports Server (NTRS)

The hardness optimization of cemented carbides is discussed. TaC-based cermets, cermets with low nonmetal/metal ratios, and composites with hard phases formed by the decomposition of Ta carbon-nitrides are described. The optimization of WC hard alloys with a FeCoNi binder, and phase relations in nitride and nitride/metal systems are reported.

Holleck, H.; Thuemmier, F.

1983-01-01

134

Geometric optimization for radiation hardness assurance  

NASA Astrophysics Data System (ADS)

The probability of a single event effect occurring is generally a function of the energy deposited in a sensitive volume, which is typically expressed as the absorbed dose in that volume. For short segments of high energy particle tracks, the dose due to a single event is proportional to the chord length through the sensitive volume. Thus, the distribution of dose in chord length is likely to relate to the probability of single event effects. For various geometries, a differential chord length distribution was generated and from this the dose distribution, frequency mean chord length, and dose mean chord length were calculated. In every case, the dose mean chord length was greater than the frequency mean chord length by a minimum of 26% and increased with the eccentricity of the volume. The large value of the dose mean chord length relative to the frequency mean chord length demonstrates the need to consider rare, long-chord-length crossings in radiation hardness testing, despite their relatively low probability of occurrence.

Northum, J.; Guetersloh, S.

135

Implementing QML for radiation hardness assurance  

NASA Astrophysics Data System (ADS)

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 manufacture of 400-k-ohm feedback resistors required to provide SEU tolerance do not conform to 6 sigma quality standards. For total-dose, interface trap charge, Delta Vit, shifts measured on transistors are correlated with circuit response in the space environment. Statistical process control (SPC) is illustrated for Delta Vit, and violations of SPC rules are interpreted in terms of continuous improvement. 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, 3-D device-plus-circuit codes, and improved design simulators.

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

1990-12-01

136

Hard exclusive photoproduction of $?$ and $J/?$ mesons  

E-print Network

We consider the reaction $\\gamma p \\to M p$, with M being either a $\\Phi$ or a $J/\\Psi$ meson, within perturbative QCD treating the proton as a quark-diquark system. The phenomenological couplings of gauge bosons to (spatially extended) diquarks and the quark-diquark distribution amplitude of the proton are adopted from previous investigations of baryon form factors and two-photon processes. Going beyond leading order, we take into account hadron-mass effects by a systematic expansion in the small parameter (hadron mass/ photon energy). With the meson distribution amplitudes taken from the literature our predictions for the differential cross section at $| t | \\agt 3 \\hbox{GeV}^2$ seem to provide a reasonable extrapolation of the low-$t$ data in case of the $\\Phi$. They fail, however, completely for the $J/\\Psi$. A closer inspection reveals that `` hadron-mass corrections\\rq\\rq become dominant for t values of only a few GeV in case of the $J/\\Psi$. This indicates that one has to go to much larger energies and momentum transfers in order to achieve a reliable description of $J/\\Psi$ production within the hard-scattering approach.

C. F. Berger; W. Schweiger

1999-09-07

137

Successes and failures with hard probes  

E-print Network

The two major pillars of searches for the Quark Gluon Plasma have been: J/$\\Psi$ suppression, proposed in 1986, and observed at both SPS fixed target energies and at RHIC; and, more recently, the suppression of $\\pi^0$ with $p_T\\geq 3$ GeV/c by a factor $\\sim 5$ in Au+Au central collisions, observed at RHIC in 2001, which had been predicted in advance as a consequence of Landau-Pomeranchuck-Migdal coherent (gluon) bremsstrahlung by the outgoing hard-scattered partons traversing the medium. However, new effects were discovered and the quality of the measurements greatly improved so that the clarity of the original explanations has become obscured. For instance: J/$\\Psi$ suppression is the same at SpS and RHIC. Is it the QGP, comovers, something else? QCD provides beautiful explanations of $\\pi^0$ and direct $\\gamma$ measurements in p-p collisions but precision fits of the best theories of $\\pi^0$ suppression barely agree with the Au+Au data. Better data are needed for $10< p_T <20$ GeV/c, systematic errors are needed in theory calculations, the values of parameters of the medium such as $\\mean{\\hat{q}}$ derived from precision fits are the subject of controversy. ... These and other issues will be discussed with a view to identify which conclusions are firm and where further progress towards real understanding is required.

M. J. Tannenbaum

2008-11-04

138

Periodically kicked hard oscillators G. A. Cecchi  

E-print Network

Periodically kicked hard oscillators G. A. Cecchi Departamento de Fisica, U.N.L.P.,Argentina D. L for publication 25 November 1992) A model of a hard oscillator with analytic solution is presented. Its behavior. It is shown that the general structure of such an oscillator includes four distinct regions; the outer two

139

Retraction of Hard, Lozano, and Tversky (2006)  

ERIC Educational Resources Information Center

Reports a retraction of "Hierarchical encoding of behavior: Translating perception into action" by Bridgette Martin Hard, Sandra C. Lozano and Barbara Tversky (Journal of Experimental Psychology: General, 2006[Nov], Vol 135[4], 588-608). All authors retract this article. Co-author Tversky and co-author Hard believe that the research results cannot

Hard, B. M.; Lozano, S. C.; Tversky, B.

2008-01-01

140

Spectral Bounds on General Hard Core Predicates ?  

E-print Network

of functions computable in AC 0 . The above bound on sensitivity is obtained by (lower) bounding the high order(x). A hard core predicate, though a basic primitive, has remarkably potency: { If f is a permutation, a hard of Goldmann and Naslund [2] shows that they cannot, in general, be computed in AC 0 . We strengthen

Russell, Alexander

141

Matrix of Hard and Soft Skills  

NSDL National Science Digital Library

This document was developed by Access Tech Careers to support successful course completion for students with learning disabilities. This matrix displays intersections between hard skills, including reading, writing, oral communication, and math, with soft skills, including critical thinking, teamwork, professionalism, and adaptability. It can help instructors integrate hard and soft skills in course planning.

2012-07-24

142

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

SciTech Connect

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.

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

143

Prediction of a Structural Transition in the Hard Disk Fluid  

E-print Network

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.

Jaroslaw Piasecki; Piotr Szymczak; John J. Kozak

2010-09-16

144

Quadratic and Linear Models for Predicting the Hardness of Heat Affected Zone in Air Cooled Cast Iron Weldment in Relation to the HAZ Hardness of Aluminum and Mild Steel Weldments Cooled in Same Media  

Microsoft Academic Search

Successful attempt has been made to derive quadratic and linear models for predicting the HAZ hardness of air cooled cast iron weldment in relation to the combined and respective values of HAZ hardness of aluminum and mild steel welded and cooled under the same conditions. It was discovered that the general model; ? = (2.9774? - ?)\\/2 + ?(((?- 2.9774?)\\/2)

Chukwuka Ikechukwu Nwoye

2009-01-01

145

Plasma-assisted growth of bilayer silicon-containing coatings for hardness and corrosion resistance  

NASA Astrophysics Data System (ADS)

Hard corrosion-resistant bilayer coatings were grown in a high-density microwave electron cyclotron resonance discharge. The bilayer coatings consist of a relatively soft (0.6-1.5 GPa) polymer-like coating as the adherent bottom layer and a much harder (8-12 GPa) top layer. The polymer underlayers were grown from 100% octamethylcyclotetrasiloxane (OMCTS) while the hard top layer was either silicon dioxide grown from OMCTS in an oxygen plasma or silicon nitride grown from hexamethyldisiloxane in an ammonia plasma. The bilayer structures combined high surface hardness values with good corrosion resistance, surviving 1800-2600 h in an ASTM B117 salt-fog corrosion test. .

Xiao, Z. G.; Mantei, T. D.

2004-07-01

146

Dynamic effects on target hardness  

SciTech Connect

A two-dimensional finite-element model of a tunnel in a soil island has been constructed using DYNA2D. This model is subjected to a triangular pressure pulse that travels through the grid, allowing tunnel hardness to be evaluated as in the analytical Hendron-Aiyer (HA) method. The DYNA2D model accounts for all the dependencies in the HA model, and also provides a more accurate description of geometric and dynamic effects. However, the speed of the DYNA2D model (1 to 5 minutes on the Cray-XMP) allows a variety of scenarios to be explored; thus a common disadvantage of large' numerical models is avoided. The most obvious dynamic effect observed is the sequential- multi-burst (SMB) principle. Results of numerous DYNA2D runs on small-diameter tunnels indicate that two pressure pulses generally cause more damage than a single pressure pulse, even if the peak pressure in the single pulse is as much as 40 percent greater than either of the two pulses. Thus, a single peak pressure (as in Hendron-Aiyer) does not emerge as an appropriate tunnel kill criterion, especially if tunnel kill is assumed to relate to deformation of the tunnel rather than G-loadings. This trend holds especially for structures where tunnel strength is of the order of surrounding rock strength; i.e., tunnels in tuff or similar rock. In contrast, it does not seem to hold for a steel tunnel' in water. The SMB concept is of significant interest, since it can potentially lower the kill pressure if several bursts are used. Also, SMB appears to be insensitive to the time interval between pressure pulses. 8 refs., 35 figs.

Logan, R.W.

1989-06-20

147

Holographic gravitational infall in the hard wall model  

NASA Astrophysics Data System (ADS)

An infalling shell in the hard wall model provides a simple holographic model for energy injection in a confining gauge theory. Depending on its parameters, a scalar shell either collapses into a large black brane, or scatters between the hard wall and the anti-de Sitter boundary. In the scattering regime, we find numerical solutions that keep oscillating for as long as we have followed their evolution, and we provide an analytic argument that shows that a black brane can never be formed. This provides examples of states in infinite-volume field theory that never thermalize. We find that the field theory expectation value of a scalar operator keeps oscillating, with an amplitude that undergoes modulation.

Craps, Ben; Lindgren, E. J.; Taliotis, Anastasios; Vanhoof, Joris; Zhang, Hongbao

2014-10-01

148

Hard X-ray Radiation in the Coma Cluster  

NASA Astrophysics Data System (ADS)

Hard X-ray radiation has been detected for the first time in the Coma cluster spectrum, during the AO-1 observations. Thanks to the unprecedented sensitivity of the Phoswich Detection System (PDS) onboard the Beppo-SAX observatory, the source has been detected up to ~80 keV. There is clear evidence for non-thermal emission in excess to the thermal one above ~25 keV at a 4.5 sigma level. Our analysis is able to exclude that the hard excess may be due to X Comae, a type I Seyfert galaxy present in the FOV of the PDS. A volume-averaged intracluster magnetic field of 0.16 mu G is derived, in order to account for the observed syncrotron radio emission. This value is in contrast with the estimates based on Faraday rotation measurements seen through the hot intracluster medium of the Coma Cluster.

Fusco-Femiano, R.; dal Fiume, D.; Feretti, L.; Giovannini, G.; Matt, G.; Molendi, S.

1998-12-01

149

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

E-print Network

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.

Mingcheng Yang; Hongru Ma

2008-06-23

150

Estimating the unconfined compressive strength of intact rocks from Equotip hardness  

Microsoft Academic Search

In order to utilize the Equotip hardness tester, originally developed in the field of metallic engineering, as an indirect\\u000a method to predict the unconfined compressive strength (UCS) of rock, laboratory tests were undertaken to establish the UCS,\\u000a Equotip hardness (L-value) and porosity of nine rock types. Using existing data from Verwaal and Mulder (Int J Rock Mech Min Sci Geomech

Hisashi Aoki; Yukinori Matsukura

2008-01-01

151

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

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

152

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...

153

Correlation of Yield Strength and Tensile Strength with Hardness for Steels  

Microsoft Academic Search

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

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

2008-01-01

154

Hardness and Tensile Strength of Multifilamentary Metal-matrix Composite Superconductors for the Large Hadron Collider (LHC)  

E-print Network

Conventional indentation hardness measurements to obtain load independent Vickers hardness values for the different phases in multifilamentary superconducting (SC) wires are described. The concept of composite hardness is validated for a binary metal-matrix metal-filament Nb-Ti/Cu composite wire. The tensile materials properties of the individual wire components are estimated from their indentation hardness. The potential and limitations of this approach are critically discussed, based on a comparison with tensile test results obtained for wires and extracted Nb-Ti filaments.

Scheuerlein, C; Leroy, D; Oberli, L; Rehmer, B

2007-01-01

155

Theory of hard diffraction and rapidity gaps  

SciTech Connect

In this talk we review the models describing the hard diffractive production of jets or more generally high-mass states in presence of rapidity gaps in hadron-hadron and lepton-hadron collisions. By rapidity gaps we mean regions on the lego plot in (pseudo)-rapidity and azimuthal angle where no hadrons are produced, between the jet(s) and an elastically scattered hadron (single hard diffraction) or between two jets (double hard diffraction). {copyright} {ital 1996 American Institute of Physics.}

Del Duca, V. [Deutsches Elektronen-Synchrotron DESY, D-22603 Hamburg (Germany)

1996-02-01

156

Computer simulation of charged hard spherocylinders  

NASA Astrophysics Data System (ADS)

In this work we present a computer simulation study of charged hard spherocylinders of aspect ratio L /?=5, using NVT and NPT Monte Carlo methods. Coulombic interactions are handled using the Wolf method [D. Wolf, P. Keblinski, S. R. Phillpot, and J. Eggebrecht, J. Chem. Phys. 110, 8254 (1999)]. Thermodynamic and structural properties are in excellent agreement with the results obtained with the standard Ewald summation method. A partial prediction of the corresponding phase diagram is obtained by studying two isotherms of this system. The stability of the liquid crystalline phases is examined and compared with the phase diagrams of neutral hard spherocylinders and dipolar hard spherocylinders.

Avenda駉, Carlos; Gil-Villegas, Alejandro; Gonz醠ez-Tovar, Enrique

2008-01-01

157

Computer simulation of charged hard spherocylinders.  

PubMed

In this work we present a computer simulation study of charged hard spherocylinders of aspect ratio L/sigma=5, using NVT and NPT Monte Carlo methods. Coulombic interactions are handled using the Wolf method [D. Wolf, P. Keblinski, S. R. Phillpot, and J. Eggebrecht, J. Chem. Phys. 110, 8254 (1999)]. Thermodynamic and structural properties are in excellent agreement with the results obtained with the standard Ewald summation method. A partial prediction of the corresponding phase diagram is obtained by studying two isotherms of this system. The stability of the liquid crystalline phases is examined and compared with the phase diagrams of neutral hard spherocylinders and dipolar hard spherocylinders. PMID:18247968

Avenda駉, Carlos; Gil-Villegas, Alejandro; Gonz醠ez-Tovar, Enrique

2008-01-28

158

NNLO hard functions in massless QCD  

E-print Network

We derive the hard functions for all 2->2 processes in massless QCD up to next-to-next-to-leading order (NNLO) in the strong coupling constant. By employing the known one- and two-loop helicity amplitudes for these processes, we obtain analytic expressions for the ultraviolet and infrared finite, minimally subtracted hard functions, which are matrices in color space. These hard functions will be useful in carrying out higher-order resummations in processes such as dijet and highly energetic top-quark pair production by means of soft-collinear effective theory methods.

Alessandro Broggio; Andrea Ferroglia; Ben D. Pecjak; Zhibai Zhang

2014-09-18

159

Take a Long, Hard Look  

ERIC Educational Resources Information Center

The mooted development of a set of core British values demands a thorough re-examination of what it means to be British. The author argues that British people need to look at Britishness a bit more as others see them. For many the experience of Britishness was brutishness and it is still seen that way in the Middle East and not just by those in

Mackney, Paul

2008-01-01

160

Electronic Teaching: Hard Disks and Networks.  

ERIC Educational Resources Information Center

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)

Howe, Samuel F.

1984-01-01

161

Particle physics: Hard-core revelations  

Microsoft Academic Search

Our description of how the atomic nucleus holds together has up to now been entirely empirical. Arduous calculations starting from the theory of the strong nuclear force provide a new way into matter's hard core.

Frank Wilczek

2007-01-01

162

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 Design ApS #12;Horns Rev. Hard Bottom Substrate Monitoring Page 3 Annual Status Report 2003 Doc. No. 2230

163

Hardness ratios of different neutron spectra.  

PubMed

Extensive data have been gathered in the past on the response of different detectors, based on the registration of neutron-induced fissions in bismuth, gold, tantalum and thorium by the spark-replica counter and the thin film breakdown counter. These detectors make it possible to exploit the excellent characteristics of the fission reactions for the measurements of high-energy neutrons. Most of the investigations have been carried out at the quasi-monoenergetic neutron beam facility at The Svedberg Laboratory-TSL of the Uppsala University in cooperation with the Khlopin Radium Institute (KRI). The responses of different fission detectors in the neutron energy range 35-180 MeV have been evaluated: a region where the predictive power of available nuclear reaction models and codes is not reliable yet. For neutron energy >200 MeV, the fission-detector responses have been derived from the data of the proton fission cross sections. By using the ratio of the responses of these detectors, a simple and accurate way to evaluate the spectrum hardness can be obtained, thus providing a tool to obtain spectral information needed for neutron dosimetry without the need to know the entire spectrum. Extensive data have been already obtained for the high-energy neutron spectrum from the CERN concrete facility. In the present paper, the measured values of the response ratios for different fissile detectors exposed at the CERN facility are compared with those calculated for the spectra from the same facility and from different altitudes in the atmosphere, respectively. PMID:15353650

Tommasino, L; Tripathy, S P

2004-01-01

164

Carry Hard ICBM basing: A technical assessment  

Microsoft Academic Search

Carry Hard is a deceptive, multiple-aimpoint ICBM basing concept in which hardened, encapsulated missiles are shuttled among several thousand, low-cost, water-filled vertical shelters. Since most of the essential launch and operational support equipment is carried with the missile (not provided with each shelter), the overall system costs are reduced. High system hardness permits relatively close shelter spacing, which in turn

J. R. Harvey; A. B. Schaffer; R. Speed; A. F. Todaro

1989-01-01

165

One-dimensional gas of hard needles  

E-print Network

We study a one dimensional gas of needle-like 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 use Monte Carlo methods to calculate the pressure and elasticity coefficient of the hard-needle gas as a function of its density. The results are then compared to the same quantities obtained analytically from a transfer matrix approach.

Yacov Kantor; Mehran Kardar

2009-02-11

166

A Novel Approach to Hardness Testing  

NASA Technical Reports Server (NTRS)

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.

Spiegel, F. Xavier; West, Harvey A.

1996-01-01

167

Testing the Hardness of Common Minerals  

NSDL National Science Digital Library

This activity gives students practice and a chance to develop expertise in using the test for hardness in identifying common minerals. Following a discussion and an introduction to Moh's scale, the students will work in groups to test minerals whose identities are known against their standards (common substances whose hardnesses are known). Once the known minerals have been tested, the students can proceed to test unknown samples. A student worksheet and discussion questions are provided.

168

RAD hard PROM design study  

NASA Technical Reports Server (NTRS)

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.

1981-01-01

169

Hard Gamma Ray Emission from the Starburst Galaxy NGC 253  

NASA Technical Reports Server (NTRS)

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.

Jackson, James M.; Marscher, Alan M.

1996-01-01

170

Characterization of hard piezoelectric lead-free ceramics.  

PubMed

K4CuNb8O23 doped K(0.45)Na(0.55)NbO3(KNNKCN) 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 degrees 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 leadfree materials are desirable. PMID:19686966

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

2009-08-01

171

Characterization of Hard Piezoelectric Lead-Free Ceramics  

PubMed Central

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 揾ardening 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癈. 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

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

2010-01-01

172

Investigation Of Tool Wear In Hard Turning Using Taguchi Method  

NASA Astrophysics Data System (ADS)

Hard turning is a machining process defined of hardness higher than 45 HRC under appropriate cutting tools and cutting speed. The objective of this paper is to investigate the optimum process parameters for a particular work piece-tool material combination. . In this study, three levels of each parameters viz. Hardness (HRC), Speed(mm/min), Feed(mm/rev) and three different tool materials are evaluated for process quality characteristics such as tool wear. The three different tool materials used are High CBN, Low CBN, Mixed ceramic. AISI H 11 was taken as work piece material. The experiment is designed using Taguchi Method. The results obtained from the experiments are transformed into signal to noise (S/N) ratio and used to optimize the value of tool wear. The analysis of variance (ANOVA) is performed to indentify the statistical significance of parameters. The final results of experimental investigation are presented in this paper. The conclusions arrived at are critically discussed at the end.

Chaudhari, Y. D.

2013-03-01

173

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

SciTech Connect

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.

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

174

Modeling of the flow stress for AISI H13 Tool Steel during Hard Machining Processes  

SciTech Connect

In general, the flow stress models used in computer simulation of machining processes are a function of effective strain, effective strain rate and temperature developed during the cutting process. However, these models do not adequately describe the material behavior in hard machining, where a range of material hardness between 45 and 60 HRC are used. Thus, depending on the specific material hardness different material models must be used in modeling the cutting process. This paper describes the development of a hardness-based flow stress and fracture models for the AISI H13 tool steel, which can be applied for range of material hardness mentioned above. These models were implemented in a non-isothermal viscoplastic numerical model to simulate the machining process for AISI H13 with various hardness values and applying different cutting regime parameters. Predicted results are validated by comparing them with experimental results found in the literature. They are found to predict reasonably well the cutting forces as well as the change in chip morphology from continuous to segmented chip as the material hardness change.

Umbrello, Domenico; Rizzuti, Stefania [Department of Mechanical Engineering, University of Calabria 87036 Rende (Italy); Outeiro, Jose C. [Portuguese Catholic University, 3080-024 Figueira da Foz (Portugal); Shivpuri, Rajiv [Industrial, Welding and Systems Engineering - Ohio State University 43210 Columbus (United States)

2007-04-07

175

Hard evidence on soft skills?  

PubMed Central

This paper summarizes recent evidence on what achievement tests measure; how achievement tests relate to other measures of 揷ognitive ability like IQ and grades; the important skills that achievement tests miss or mismeasure, and how much these skills matter in life. Achievement tests miss, or perhaps more accurately, do not adequately capture, soft skills梡ersonality traits, goals, motivations, and preferences that are valued in the labor market, in school, and in many other domains. The larger message of this paper is that soft skills predict success in life, that they causally produce that success, and that programs that enhance soft skills have an important place in an effective portfolio of public policies. PMID:23559694

Heckman, James J.; Kautz, Tim

2012-01-01

176

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

PubMed

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

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

2014-04-28

177

Effect of impurities on the hardness of alkali halide single crystals  

NASA Astrophysics Data System (ADS)

Micro hardness number of KCl, KBr and KCl-Br grown by Czocharlski technique, in the presence of homovalent and aliovalent ions of different ionic radii were measured in the indentation load range from 5 to 80*10-3 N. The measured data showed that there is an indentation size effect and classical Meyer's law was used for the characterization of crystal hardness of these crystals. The Meyer's index was also found to be smaller than 2 indicating brittle material characteristic. The P.R.S. model was used for the determination of the load independent micro hardness value. Result can be explained on the basis of interaction between created dislocation and point defect. It was found that hardness of these crystals is depending on the type of impurity.

Verma, Ashok K.; Ojha, Chaturbhuj; Shrivastava, A. K.

2014-04-01

178

Values in Education and Education in Values.  

ERIC Educational Resources Information Center

The major purpose of this book is to set out some of the key issues and debates relating to the importance of values in education and of education in values. After an introductory chapter about the concept of values and values education, part 1 provides a variety of perspectives on the values that underpin contemporary education. The introduction

Halstead, J. Mark, Ed.; Taylor, Monica J., Ed.

179

Haptic Search for Hard and Soft Spheres  

PubMed Central

In this study the saliency of hardness and softness were investigated in an active haptic search task. Two experiments were performed to explore these properties in different contexts. In Experiment 1, blindfolded participants had to grasp a bundle of spheres and determine the presence of a hard target among soft distractors or vice versa. If the difference in compliance between target and distractors was small, reaction times increased with the number of items for both features; a serial strategy was found to be used. When the difference in compliance was large, the reaction times were independent of the number of items, indicating a parallel strategy. In Experiment 2, blindfolded participants pressed their hand on a display filled with hard and soft items. In the search for a soft target, increasing reaction times with the number of items were found, but the location of target and distractors appeared to have a large influence on the search difficulty. In the search for a hard target, reaction times did not depend on the number of items. In sum, this showed that both hardness and softness are salient features. PMID:23056197

van Polanen, Vonne; Bergmann Tiest, Wouter M.; Kappers, Astrid M. L.

2012-01-01

180

Abrasivity Assessment of Granitic Building Stones in Relation to Diamond Tool Wear Rate Using Mineralogy-Based Rock Hardness Indexes  

NASA Astrophysics Data System (ADS)

The objective of the present study was to determine the abrasive wear potential of granites in circular sawing using some mineralogy-based rock hardness indexes. A literature study indicated that little or no attention has been given to assessing this kind of relationship in the field of stone processing. To accomplish this objective, sawing experiments were performed on nine different granites used widely as building and decorative stone materials. The measured sawblade-specific wear rates were correlated with three different rock hardness indexes attained by combining the percentage content of hard mineral constituents with their known hardness values. Statistical analysis of the experimental data revealed that rock hardness indexes that are based on both Vickers hardness number and Rosiwal hardness could be accepted as reliable indicators of granite abrasivity. These two indexes were also found to correlate well with the average power drawn during the process. However, the rock abrasivity index based on Mohs relative scratch hardness did not show statistically significant correlations with sawblade wear rate and power drawn. Although quartz percentage content is regarded as an important abrasivity parameter by practitioners, the observations made here indicate that consideration of quartz percentage content alone is not sufficient to describe the abrasive potential of granites, and thus incorporation of other hard mineral constituents could be more suitable.

Y?lmaz, Nurdan G黱e?

2011-11-01

181

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

ERIC Educational Resources Information Center

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

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

2005-01-01

182

Generating Hard and Diverse Test Sets for NP-hard Graph Problems  

Microsoft Academic Search

In evaluating the performance of approximation algorithms for NP-hard problems, it is often necessary to resort to empirical testing. In order to do such testing it is useful to have test instances of the problem for which the correct answer is known. We present algorithms for efficiently generating test instances for some NP-hard graph problems in such a way that

Laura A. Sanchis

1995-01-01

183

Hard template synthesis of metal nanowires  

PubMed Central

Metal nanowires (NWs) have attracted much attention because of their high electron conductivity, optical transmittance, and tunable magnetic properties. Metal NWs have been synthesized using soft templates such as surface stabilizing molecules and polymers, and hard templates such as anodic aluminum oxide, mesoporous oxide, carbon nanotubes. NWs prepared from hard templates are composites of metals and the oxide/carbon matrix. Thus, selecting appropriate elements can simplify the production of composite devices. The resulting NWs are immobilized and spatially arranged, as dictated by the ordered porous structure of the template. This avoids the NWs from aggregating, which is common for NWs prepared with soft templates in solution. Herein, the hard template synthesis of metal NWs is reviewed, and the resulting structures, properties and potential applications are discussed.

Kawamura, Go; Muto, Hiroyuki; Matsuda, Atsunori

2014-01-01

184

Hard X-ray astronomy at IAS  

NASA Astrophysics Data System (ADS)

Studies of hard X-ray emission from compact galactic sources and extragalactic objects are reviewed which have been carried out in Italy since 1976. The studies include observations of galactic binary systems and peculiar stars, deep surveys of extragalactic sources, observations of the galactic hard X-ray background, and the monitoring of transient X-ray sources, gamma-ray bursts, and X-ray bursters. Attention is given to early balloon experiments, sounding-rocket flights, later balloon experiments with multiwire spectroscopic proportional counters, equatorial balloon flights in India, and an abortive trans-Atlantic balloon flight from Sicily that was terminated over Spain. Some future programs are discussed, including a deep survey of the hard X-ray sky, deep-space observations of single galactic and extragalactic sources, and the development of an imaging telescope for soft gamma-ray astronomy.

Ubertini, P.

1981-03-01

185

Erosion testing of hard materials and coatings  

SciTech Connect

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).

Hawk, Jeffrey A.

2005-04-29

186

On the quality of the hardness kernel and the Fukui function to evaluate the global hardness.  

PubMed

An approximated hardness kernel, which includes the second derivative with respect to the density of the kinetic energy, the electron-electron coulomb repulsion, and the exchange density functionals, has been tested for the calculation of the global hardness. The results obtained for a series of 40 cations and neutral systems and 16 anions represent in most cases an improvement of the results obtained using the HOMO-LUMO gap approach and indicate the viability of this approach to evaluate global hardness. In addition, the relevance of the Fukui function approximation and the role of the three components of the hardness kernel in the evaluation of the global hardness have been analyzed. PMID:17186480

Torrent-Sucarrat, Miquel; Salvador, Pedro; Geerlings, Paul; Sol, Miquel

2007-01-30

187

The physical meaning of indentation and scratch hardness  

Microsoft Academic Search

A study of the plastic deformation of metals by hard indenters shows that the indentation hardness is essentially a measure of the plastic yield stress of the metal. With pyramidal (and conical) indenters the hardness, because of geometric similarity, is independent of the size of the indentation. With spherical indenters this is not so, the hardness increasing with size of

D. Tabor

1956-01-01

188

Hard X-ray properties of magnetic cataclysmic S. Scaringi  

E-print Network

Hard X-ray properties of magnetic cataclysmic variables S. Scaringi , A.J. Bird , A.J. Norton , C arising from this hard X-ray selected sample and find that most hard X-ray detected mCVs have Pspin in the context of mCV evolution scenarios. We also present evidence for corre- lations between hard X

Norton, Andrew J.

189

Hard Diffraction at D-Zero  

SciTech Connect

Preliminary results from the DO experiment on dijet production with forward rapidity gaps in {anti p}p collisions are presented at center-of-mass {radical}s = 1800 GeV and 630GeV. The number oi events with rapidity gaps at both center-of-mass energies is significantly greater than tne expectatmn from multiplicity fluctuations and is consistent with a hard single diffractive process. We also observe an excess of events which contain jets and two rapidity gaps, a topology which is consistent with hard double pomeron exchange.

Paul Rubinov

1999-01-21

190

Hard-thermal-loop QED thermodynamics  

E-print Network

The weak-coupling expansion for thermodynamic quantities in thermal field theories is poorly convergent unless the coupling constant is tiny. We discuss the calculation of the free energy for a hot gas of electrons and photons to three-loop order using hard-thermal-loop perturbation theory (HTLpt). We show that the hard-thermal-loop perturbation reorganization improves the convergence of the successive approximations to the QED free energy at large coupling, e ~ 2. The reorganization is gauge invariant by construction, and due to the cancellations among various contributions, we obtain a completely analytic result for the resummed thermodynamic potential at three loops.

Nan Su; Jens O. Andersen; Michael Strickland

2009-11-24

191

Radiation-hard static induction transistor  

NASA Astrophysics Data System (ADS)

The design, fabriction, and characteristics of a 350-V, 100-A buried-gate static induction transistor (SIT) as a power switching device for applications to military and space environments (because of its potential for radiation hardness, high-frequency operation, and the incorporation of on-chip smart power sensor and logic functions) are described. The potential radiation hardness of this class of devices was evaluated by measurement of SIT characteristics after irradiation with 100-Mrad (2-MeV) electrons and up to 10 to the 16th fission neutrons/sq cm. High-temperature operation and the possibility of radiation-damage self-annealing are discussed.

Hanes, M. H.; Bartko, J.; Hwang, J.-M.; Rai-Choudhury, P.; Leslie, S. G.

1988-12-01

192

Degenerate quasicrystal of hard triangular bipyramids.  

PubMed

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

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

2011-11-18

193

Hard Diffraction -- from Blois 1985 to 2005  

E-print Network

The idea of diffractive processes with a hard scale involved, to resolve the underlying parton dynamics, was presented at the first Blois conference in 1985 and experimentally verified a few years later. Today hard diffraction is an active research field with high-quality data and new theoretical models. The trend from Regge-based pomeron models to QCD-based parton level models has given insights on QCD dynamics involving perturbative gluon exchange mechanisms, including the predicted BFKL-dynamics, as well as novel ideas on non-perturbative colour fields and their interactions.

Gunnar Ingelman

2005-11-15

194

Value of Travel Time.  

National Technical Information Service (NTIS)

The Record includes 6 papers covering important areas of travel time value analysis, such as travel time value theory, conceptual problems in travel time value, methods of deriving travel time values, review of empirical travel time value studies, applica...

R. Gronau

1976-01-01

195

Nanoindentation hardness and adhesion investigations of vapor deposited nanostructured diamond films  

NASA Astrophysics Data System (ADS)

The effect of changing the N2/CH4 feedgas ratio on the structure and mechanical properties of microwave plasma chemical vapor deposited diamond films grown on Ti-6Al-4V alloy substrates was investigated. The relative concentration of CH4 and N2 (in a balance of H2) was shown to strongly influence film structure, hardness, and adhesion. For high CH4 concentration (15% by volume), nanostructured diamond films with roughness magnitudes of 15-30 nm, good adhesion and a high hardness value of 90 GPa was obtained. A distinct correlation was found between the nanoindentation hardness of the deposited film and the N2/CH4 ratio in the plasma, as well as a correlation of hardness to the ratio of the Raman peak intensities (1332 and 1555 cm-1). Scratch adhesion testing of nanostructured diamond films showed delamination at a critical force of 33 N using acoustic emission techniques. These results demonstrate that nanostructured diamond films can be tailored on metallic surfaces with hardness ranging from 10 GPa (medium-hard) to 100 GPa (superhard) and may be considered for wear resistant applications such as in the design of articulating medical implant devices.

Catledge, Shane A.; Borham, James; Vohra, Yogesh K.; Lacefield, William R.; Lemons, Jack E.

2002-04-01

196

Hard and Easy Distributions of SAT Problems  

Microsoft Academic Search

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

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

1992-01-01

197

Hard Determinism and the Moral "Ought"  

E-print Network

, behave. Finally, as analogous to the instance of legal rules, one can be compelled on a hard determinist account by the threat of public criticism, ostracism, etc. and even by legal sanctions to follow the moral laws. That is, the threat of punishment...

Kuo, Lenore

1987-12-01

198

Hard Implicit Function Theorem via the DSM  

E-print Network

Sufficient conditions are given for a hard implicit function theorem to hold. The result is established by an application of the Dynamical Systems Method (DSM). It allows one to solve a class of nonlinear operator equations in the case when the Fr\\'echet derivative of the nonlinear operator is a smoothing operator, so that its inverse is an unbounded operator.

Ramm, A G

2009-01-01

199

慡OFT VERSUS HARD NEWS ON MICROBLOGGING NETWORKS  

Microsoft Academic Search

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 憇oft or hard news information. The

Tyler J. Horan

2012-01-01

200

Surface modulation of dental hard tissues  

Microsoft Academic Search

Tooth surfaces play a central role in the equilibrium of dental hard tissues, in which contrasting processes lead to loss or deposition of materials. The central interest of this Thesis was the modulation of tooth surfaces to control such equilibrium. Four specific studies were carried out to investigate different classes of surface modulating agents. These are: (1) Ionic modulation of

Daranee Tantbirojn

1998-01-01

201

HARD BREMSSTRAHLUNG PHOTONS FROM GRAVITON EXCHANGE  

E-print Network

HARD BREMSSTRAHLUNG PHOTONS FROM GRAVITON EXCHANGE #3; LC-TH-2004-015 T. BUANES, E.W. DVERGSNES Abstract We review photon Bremsstrahlung in extra-dimensional models with massive gravitons. The photon spectrum is harder than in the Standard Model. In the RS scenario, radiative return to gravitons below

202

Vortices in a Gas of Hard Spheres  

Microsoft Academic Search

We approximately describe the transition regime between two vortex-type flows in a gas of hard spheres. Such flows rotate as solid bodies about their axes, which in turn move translationally with arbitrary linear velocities. We study the asymptotic behavior of the integral norm of the discrepancy between the two sides of the Boltzmann equation under a special choice of hydrodynamic

V. D. Gordevsky

2003-01-01

203

PROTEIN TEMPLATES IN HARD TISSUE ENGINEERING  

PubMed Central

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

George, Anne; Ravindran, Sriram

2010-01-01

204

Classic and Hard-Boiled Detective Fiction.  

ERIC Educational Resources Information Center

Through an analysis of several stories, this paper defines the similarities and differences between classic and hard-boiled detective fiction. The characters and plots of three stories are discussed: "The Red House" by A. A. Milne; "I, The Jury" by Mickey Spillane; and "League of Frightened Men" by Rex Stout. The classic detective story is defined

Reilly, John M.

205

Nanoindentation hardness of submicrometer alumina ceramics  

Microsoft Academic Search

Nanoindentations at loads of 20200 mN were performed on submicrometer sintered alumina ceramics of different residual porosity. The indentation size effect of the hardness can be obtained without variation of the maximum load directly from loading curves, if the Young's modulus of the material is known and if the shape of the penetration curve is analyzed carefully. Similar influences of

A Krell; S Sch鋎lich

2001-01-01

206

EQUIPMENT FOR HARDNESS TESTING AT ELEVATED TEMPERATURES  

Microsoft Academic Search

The design and testing procedures of two elevatedtemperature hardness ; testers are described. One device uses a Rockwell tester with a large vertical ; capacity and a load range of 15 to 150 kg. The tester is equipped with a 900 deg ; C heating chamber which maintains an argon atmosphere over the specimen and can ; be laterally displaced

G. Hallerman; R. J. Gray

1963-01-01

207

FORCE CALIBRATION OF INSTRUMENTED HARDNESS TESTERS  

Microsoft Academic Search

In this paper a methodology for calibration of force transducers used for hardness testers is described. The methodology associates to the standard procedure a method to evaluate and correct other effects such as promptness, creep and hysteresis. After a general description, a practical application is reported.

Giulio Barbato; Gabriele Brondino; Maurizio Galetto

2003-01-01

208

CRITICAL PERSISTENT CURRENTS IN HARD SUPERCONDUCTORS  

Microsoft Academic Search

Persistent currents induced in hard superconductors (HSC) were ; investigated by measuring the resulting magnetic effects. The tubular HSC ; examined were Nb powder, Nb釹n, and 3Nb- Zr samples of uniform wall ; thickness and length large compared to the diameter. Experimental evidence is ; presented that in HSC the Lorentz force plays a crucial role in determining the ;

Y. B. Kim; C. F. Hempstead; A. R. Strnad

1962-01-01

209

Hard Times: Philosophy and the Fundamentalist Imagination  

ERIC Educational Resources Information Center

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

Allsup, Randall Everett

2005-01-01

210

Sustaining Transformation: "Resiliency in Hard Times"  

ERIC Educational Resources Information Center

The strategic, systemic, and encompassing evolution of a college or university spans a number of years, and the vagaries of economic cycles inevitably catch transforming institutions in mid-voyage. "Sustaining Transformation: Resiliency in Hard Times" presents a study of Wagner College as it moves into its second decade of purposeful institutional

Guarasci, Richard; Lieberman, Devorah

2009-01-01

211

Radiation-Hardness Data For Semiconductor Devices  

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

212

Where the Really Hard Problems Are  

Microsoft Academic Search

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 \\

Peter Cheeseman; Bob Kanefsky; William M. Taylor

1991-01-01

213

Hard thermal loops in static external fields  

E-print Network

We study, in the imaginary-time formalism, the high temperature behavior of n-point thermal loops in static Yang-Mills and gravitational fields. We show that in this regime, any hard thermal loop gives the same leading contribution as the one obtained by evaluating the loop at zero external energies and momenta.

J. Frenkel; S. H. Pereira; N. Takahashi

2009-02-04

214

Approximation Algorithms for NP-Hard Problems  

Microsoft Academic Search

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 \\

1997-01-01

215

On the hardness of approximating minimization problems  

Microsoft Academic Search

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

Carsten Lund; Mihalis Yannakakis

1993-01-01

216

Dynamic hardness testing of metallic materials  

Microsoft Academic Search

A method of hardness testing is presented based on the measurement of the kinetic energy components of impact and rebound of the testing body. The testing instrument consists of an impact device and an electronic indicator device. The impact and rebound velocities are measured in a contactless manner by means of an electromagnetic transmitter and the result from dividing the

D. Leeb

1979-01-01

217

Hard and flexible optical printed circuit board  

NASA Astrophysics Data System (ADS)

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.

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

2007-02-01

218

Influence of workpiece hardness on EDM performance  

Microsoft Academic Search

The aim of this research is to show the influence of the hardness of the alloy steel on the material removal rate and on the workpiece surface roughness.The Taguchi methodology was used to study that influence. The result of the verification test for workpiece surface roughness was a strong confirmation. This type of outcome allows the use of the additive

Jos Duarte Marafona; Arlindo Ara鷍o

2009-01-01

219

Hard thermal loops in static external fields  

SciTech Connect

We examine, in the imaginary-time formalism, the high temperature behavior of n-point thermal loops in static Yang-Mills and gravitational fields. We show that in this regime, any hard thermal loop gives the same leading contribution as the one obtained by evaluating the loop integral at zero external energies and momenta.

Frenkel, J.; Takahashi, N. [Universidade de Sao Paulo, Instituto de Fisica Rua do Matao, Travessa R, 187-05508-090 Cidade Universitaria, Sao Paulo, SP (Brazil); Pereira, S. H. [Universidade de Sao Paulo, Instituto de Astronomia, Geofisica e Ciencias Atmosfericas Rua do Matao, 1226-05508-090 Cidade Universitaria, Sao Paulo, SP (Brazil)

2009-04-15

220

Structure the Hard Sphere Solid Charles Radin  

E-print Network

interested solid phase the sphere model, phase which is generally agreed exist based computer experimentsStructure the Hard Sphere Solid Charles Radin * Lorenzo Sadun Department of Mathematics, University (centers the) spheres. We be concerned with solid颅fluid transi颅 tion, associated d around 0

221

Fundamental of Hard Disk Drive Technology (7)  

E-print Network

Fundamental of Hard Disk Drive Technology (7) Assistant Prof. Piya Kovintavewat, Ph.D. Data Storage for "Integrated Drive Electronics", sometimes called Parallel ATA (PATA) Originally developed as a joint effort and cooling Longer 1 meter cable lengths allowed Software Compatibility SATA is a drop-in replacement for PATA

Kovintavewat, Piya

222

Classic Nintendo Games are (Computationally) Hard  

E-print Network

-6922462. 4 We exclude the Zelda CD-i games by Philips Media, which Nintendo does not list as part]). In addition, we show that several Zelda games are PSPACE-complete by reducing from PushPush-1 [3]. We canClassic Nintendo Games are (Computationally) Hard Greg Aloupis1 , Erik D. Demaine2 , Alan Guo2

Demaine, Erik

223

Help! Libraries and the Hard of Hearing.  

ERIC Educational Resources Information Center

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

1982

224

Cryptographic Hardness of Random Local Functions Survey  

E-print Network

Cryptographic Hardness of Random Local Functions 颅 Survey Benny Applebaum School of Electrical of their output bits depend on a constant number of input bits. The feasibility of such highly efficient-local predicate P to a randomly chosen d-size subset of the input bits. Formally, this can be viewed as selecting

Applebaum, Benny

225

Heat treatment effect on microstructure, hardness and wear resistance of Cr26 white cast iron  

NASA Astrophysics Data System (ADS)

High chromium cast iron(HCCI) is taken as material of coal water slurry pump impeller, but it is susceptible to produce serious abrasive wear and erosion wear because of souring of hard coal particles. The research on optimization of heat treatments to improve abrasive wear properties of HCCI is insufficient, so effect of heat treatments on the microstructure, hardness, toughness, and wear resistance of Cr26 HCCI is investigated to determine the optimal heat treatment process for HCCI. A series of heat treatments are employed. The microstructures of HCCI specimens are examined by using optical microscopy and scanning electron microscopy. The hardness and impact fracture toughness of as-cast and heat treated specimens are measured. The wear tests are assessed by a Type M200 ring-on block wear tester. The results show the following: With increase of the quenching temperature from 950 癈 to 1050 癈, the hardness of Cr26 HCCI increased to a certain value, kept for a time and then decreased. The optimal heat treatment process is 2 h quenching treatment at 1000 癈, followed by a subsequent 2 h tempering at 400 癈. The hardness of HCCI is related to the precipitation and redissolution of secondary carbides in the process of heat treatment. The subsequent tempering treatment would result in a slight decrease of hardness but increase of toughness. The wear resistance is much related to the "supporting" effect of the matrix and the "protective" effect of the hard carbide embedded in the matrix, and the wear resistance is further dependent on the hardness and the toughness of the matrix. This research can provide an important insight on developing an optimized heat treatment method to improve the wear resistance of HCCI.

Zhou, Shaoping; Shen, Yehui; Zhang, Hao; Chen, Dequan

2014-08-01

226

Financial and environmental modelling of water hardness--implications for utilising harvested rainwater in washing machines.  

PubMed

A study was conducted to determine the financial and environmental effects of water quality on rainwater harvesting systems. The potential for replacing tap water used in washing machines with rainwater was studied, and then analysis presented in this paper is valid for applications that include washing machines where tap water hardness may be important. A wide range of weather conditions, such as rainfall (284-1,794 mm/year); water hardness (14-315 mg/L CaCO3); tap water prices (0.85-2.65 Euros/m(3)) in different Spanish urban areas (from individual buildings to whole neighbourhoods); and other scenarios (including materials and water storage capacity) were analysed. Rainfall was essential for rainwater harvesting, but the tap water prices and the water hardness were the main factors for consideration in the financial and the environmental analyses, respectively. The local tap water hardness and prices can cause greater financial and environmental impacts than the type of material used for the water storage tank or the volume of the tank. The use of rainwater as a substitute for hard water in washing machines favours financial analysis. Although tap water hardness significantly affects the financial analysis, the greatest effect was found in the environmental analysis. When hard tap water needed to be replaced, it was found that a water price of 1 Euro/m(3) could render the use of rainwater financially feasible when using large-scale rainwater harvesting systems. When the water hardness was greater than 300 mg/L CaCO3, a financial analysis revealed that an net present value greater than 270 Euros/dwelling could be obtained at the neighbourhood scale, and there could be a reduction in the Global Warming Potential (100 years) ranging between 35 and 101 kg CO2 eq./dwelling/year. PMID:24262990

Morales-Pinz髇, Tito; Lurue馻, Rodrigo; Gabarrell, Xavier; Gasol, Carles M; Rieradevall, Joan

2014-02-01

227

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

ERIC Educational Resources Information Center

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

Rutkowski, David; Engel, Laura C.

2010-01-01

228

On the stability of the plastic crystal phase of hard dumbbell solids  

Microsoft Academic Search

We consider the thermodynamic properties of the solid phase and solid-fluid phase equilibria of hard dumbbells. The focus of the present work is a more detailed study of the stability of the orientationally disordered (plastic crystal) solid phase relative to other solid phases and to the fluid. Our results indicate that the plastic crystal is not stable for values of

C. Vega; E. P. A. Paras; P. A. Monson

1992-01-01

229

Two approaches for enhancing the accuracy of the Rockwell hardness test  

Microsoft Academic Search

Two approaches have been investigated in our study in order to develop indenter calibration methods with high accuracy. One approach is by establishing a group standard utilizing several indenters, which yields better statistical results than the calibration using only one indenter. The second approach is by correcting the hardness test values using the indenter's area function determined by a highly

Gaoliang Dai; Konrad Herrmann; Febo Menelao

2009-01-01

230

Physiological, perceptual, and technical responses to on-court tennis training on hard and clay courts.  

PubMed

The aim of this study was to investigate the effect of court surface (clay vs. hard court) on technical, physiological, and perceptual responses to on-court tennis training. Four high-performance junior male players performed 2 identical training sessions on hard and clay courts, respectively. Sessions included both physical conditioning and technical elements as led by the coach. Each session was filmed for later notational analysis of stroke count and error rates. Furthermore, players wore a global positioning satellite device to measure distance covered during each session, while heart rate, countermovement jump distance, and capillary blood measures of metabolites were measured before, during, and after each session. Additionally, a respective coach and athlete rating of perceived exertion (RPE) were measured after each session. Total duration and distance covered during each session were comparable (p > 0.05; d < 0.20). Although forehand and backhands stroke volume did not differ between sessions (p > 0.05; d < 0.30), large effects for increased unforced and forced errors were present on the hard court (p > 0.05; d > 0.90). Furthermore, large effects for increased heart rate, blood lactate, and RPE values were evident on clay compared with hard courts (p > 0.05; d > 0.90). Additionally, although player and coach RPE on hard courts were similar, there were large effects for coaches to underrate the RPE of players on clay courts (p > 0.05; d > 0.90). In conclusion, training on clay courts results in trends for increased heart rate, lactate, and RPE values, suggesting that sessions on clay courts tend towards higher physiological and perceptual loads than hard courts. Furthermore, coaches seem effective at rating player RPE on hard courts but may underrate the perceived exertion of sessions on clay courts. PMID:22890497

Reid, Machar M; Duffield, Rob; Minett, Geoffrey M; Sibte, Narelle; Murphy, Alistair P; Baker, John

2013-06-01

231

Interfacial phenomena in hard-rod fluids  

NASA Astrophysics Data System (ADS)

This thesis addresses questions of interfacial ordering in hard-rod fluids at coexistence of the isotropic and nematic phases and in their contact with simple model substrates. It is organized as follows. Chapter II provides some background information about the relation between the statistical mechanical and thermodynamical level of descriptions of bulk hard-rod fluids, as well as introduces the asymptotically exact Onsager model, and some basic facts of interfacial thermodynamics. Chapter III represents studies of the simplest free IN interface in a fluid of monodisperse Onsager hard rods. For the analysis of this system we develop an efficient perturbative method to determine the (biaxial) one-particle distribution function in inhomogeneous systems. Studies of the free planar isotropic-nematic interfaces are continued in Chapter IV, where they are considered in binary mixtures of hard rods. For sufficiently different particle shapes the bulk phase diagrams of these mixtures exhibit a triple point, where an isotropic (I) phase coexists with two nematic phases (N1 and N2) of different composition. For all explored mixtures we find that upon approach of the triple point the IN2 interface shows complete wetting by an intervening N1 film. We compute the surface tension of isotropic-nematic interfaces, and find a remarkable increase with fractionation. These studies are complemented by an analysis of bulk phase behavior and interfacial properties of nonadditive binary mixtures of thin and thick hard rods in Chapter V. The formulation of this model was motivated by recent experiments in the group of Fraden, who explored the phase behavior of a mixture of viruses with different effective diameters. In our model, species of the same types are considered as interacting with the hard-core repulsive potential, whereas the excluded volume for dissimilar rods is taken to be larger (smaller) then for the pure hard rods. Such a nonadditivity enhances (reduces) fractionation at the isotropic-nematic (IN) coexistence and may induce (suppress) a demixing of the high-density nematic phase into two nematic phases of different composition (N1 and N2). Studies of their interfaces show an increase of the surface tension with fractionation at the IN interface, and complete wetting of the IN2 interface by the N1 phase upon approach of the triple point coexistence. In all explored cases bulk and interfacial properties of the nonadditive mixtures exhibit a surprising similarity with the properties of additive mixtures of larger diameter ratio. In Chapter VI we consider properties of a monodisperse hard-rod fluid in contact with the single wall (W). Studies of surface properties of a fluid of Onsager hard rods represent significant numerical difficulties, therefore we consider a simpler model fluid of hard rods with a restricted number of allowed orientations. Within this model, known as the Zwanzig model, we explore the thermodynamic properties of a fluid of monodisperse hard rods in contact with a model substrate represented by a hard wall with a short-ranged attractive or repulsive ``tail''. The attraction enhances the orientational ordering near the wall in both isotropic and nematic phases, and shifts the transition from uniaxial (U) to biaxial (B) symmetry in the isotropic surface layer to lower chemical potentials, whereas the wetting properties of the substrate remain similar to those of the pure hard wall. The soft repulsion reduces the density in the surface layer, which leads to the shift (or even suppression) of the UB transition, and strong modification of wetting properties. At the WI interface one always finds the wetting transition at sufficiently large repulsion, whereas a drying transition at the WN interface is observed only for sufficiently long-ranged potentials. In Chapter VII we explore some limitations of models of hard-rod fluids with a finite number of allowed orientations. Within Onsager's second virial theory we construct their bulk phase diagrams. For a one-component fluid, we show that the discretization of the orien

Shundyak, K. Y.

2004-05-01

232

Correlation of Yield Strength and Tensile Strength with Hardness for Steels  

Microsoft Academic Search

Hardness values as well as yield and tensile strength values were compiled for over 150 nonaustenitic, hypoeutectoid steels\\u000a having a wide range of compositions and a variety of microstructures. The microstructures include ferrite, pearlite, martensite,\\u000a bainite, and complex multiphase structures. The yield strength of the steels ranged from approximately 300燤Pa to over 1700燤Pa.\\u000a Tensile strength varied over the range of

E. J. Pavlina; C. J. Van Tyne

2008-01-01

233

What's the Value in Value-Added?  

ERIC Educational Resources Information Center

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

Duffrin, Elizabeth

2011-01-01

234

Hard-on-Hard Lubrication in the Artificial Hip under Dynamic Loading Conditions  

PubMed Central

The tribological performance of an artificial hip joint has a particularly strong influence on its success. The principle causes for failure are adverse short- and long-term reactions to wear debris and high frictional torque in the case of poor lubrication that may cause loosening of the implant. Therefore, using experimental and theoretical approaches models have been developed to evaluate lubrication under standardized conditions. A steady-state numerical model has been extended with dynamic experimental data for hard-on-hard bearings used in total hip replacements to verify the tribological relevance of the ISO 14242-1 gait cycle in comparison to experimental data from the Orthoload database and instrumented gait analysis for three additional loading conditions: normal walking, climbing stairs and descending stairs. Ceramic-on-ceramic bearing partners show superior lubrication potential compared to hard-on-hard bearings that work with at least one articulating metal component. Lubrication regimes during the investigated activities are shown to strongly depend on the kinematics and loading conditions. The outcome from the ISO gait is not fully confirmed by the normal walking data and more challenging conditions show evidence of inferior lubrication. These findings may help to explain the differences between the in vitro predictions using the ISO gait cycle and the clinical outcome of some hard-on-hard bearings, e.g., using metal-on-metal. PMID:23940772

Sonntag, Robert; Reinders, J鰎n; Rieger, Johannes S.; Heitzmann, Daniel W. W.; Kretzer, J. Philippe

2013-01-01

235

Density fluctuations and the structure of a nonuniform hard sphere fluid  

E-print Network

We derive an exact equation for density changes induced by a general external field that corrects the hydrostatic approximation where the local value of the field is adsorbed into a modified chemical potential. Using linear response theory to relate density changes self-consistently in different regions of space, we arrive at an integral equation for a hard sphere fluid that is exact in the limit of a slowly varying field or at low density and reduces to the accurate Percus-Yevick equation for a hard core field. This and related equations give accurate results for a wide variety of fields.

Kirill Katsov; John D. Weeks

2000-08-08

236

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

USGS Publications Warehouse

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)

Krumhardt, Andrea P.

1979-01-01

237

The Value of Reciprocity  

ERIC Educational Resources Information Center

The value of reciprocity in social exchange potentially comprises both instrumental value (the value of the actual benefits received from exchange) and communicative or symbolic value (the expressive and uncertainty reduction value conveyed by features of the act of reciprocity itself). While all forms of exchange provide instrumental value, we

Molm, Linda D.; Schaefer, David R.; Collett, Jessica L.

2007-01-01

238

``Good-Walker'' + QCD dipoles = Hard Diffraction  

E-print Network

The Good-Walker mechanism for diffraction is shown to provide a link between total and diffractive structure functions and to be relevant for QCD calculations at small x_{Bj}. For Deep-Inelastic scattering on a small-size target (cf. an onium) the r\\^ ole of Good-Walker ``diffractive eigenstates'' is played by the QCD dipoles appearing in the $1/N_C$ limit of QCD. Hard diffraction is thus related to the QCD tripe-dipole vertex which has been recently identified (and calculated) as being a conformal invariant correlator and/or a closed-string amplitude. An extension to hard diffraction at HERA via $k_T-$factorisation of the proton vertices leads to interesting phenomenology.

R. Peschanski

1998-05-14

239

Hardness evaluation with an optical ring light.  

PubMed

Evaluation of hardness by interrogating the residual indentation in a static test using a microscope can be hampered by poor image quality. Image digitization with processing may overcome this but is limited by cost, convenience, and speed. It is shown that the indented surface on the sample in a Brinell test acts effectively as a spherical mirror. Thus, placement of an optical ring light coaxial with the microscope objective and at varying distances from the sample surface produces a distinct right light image that can be correspondingly altered in diameter. The Brinell hardness can be computed by determining the ring light to sample distance after adjusting the ring light image diameter to equal the indentation diameter. This approach is verified experimentally and found to be accurate, cost effective, and expeditious. PMID:17339933

Ng, Tuck Wah

2007-04-01

240

Measuring the fracture resistance of hard coatings  

NASA Astrophysics Data System (ADS)

A way of characterizing cracking in a hard coating is described. Microscale double cantilever beams have been made by focused ion beam milling and compressed in situ using a nanoindenter. The method can account for frictional effects and is demonstrated first on single crystals of SiC and GaAs of known toughness, before studying cracking in CrN-based hard coatings. It is found that ultra-fine grained CrAlN/Si3N4 coatings have a toughness approximately twice that of a conventional CrN coating. Although grain-size effects are still unclear, in situ observations directly show crack interactions with particles of Cr and voids in the film.

Liu, S.; Wheeler, J. M.; Howie, P. R.; Zeng, X. T.; Michler, J.; Clegg, W. J.

2013-04-01

241

Papillary cystadenocarcinoma of the hard palate.  

PubMed

Papillary cystadenocarcinoma (PCC) is an uncommon malignant tumour of the salivary gland, sometimes involving the minor salivary gland. Previously this entity was classified as an atypical type of adenocarcinoma, malignant papillary cystadenoma, low-grade papillary adenocarcinoma or mucus producing adenopapillary carcinoma. PCC is a glandular tumour with an indolent biological behaviour characterised by cysts and papillary endophytic projections. We report two cases of PCC involving the minor salivary gland of the hard palate. Both the patients presented with a swelling in the palate with difficulty in chewing. MRI revealed an extensively destructive lesion involving hard palate, alveolar ridge and maxillary antrum. Clinical and radiological features suggested the malignant nature of the lesion. Histopathology of incisional biopsy revealed tumour proliferation in a multicystic pattern, with extensive papillary proliferation. Diverse and cellular cytomorphology, and cellular and nuclear pleomorphism with few mitotic figures were the prominent features. Both the lesions were confirmed as PCC. PMID:24408937

Wanjari, Sangeeta Panjab; Wanjari, Panjab Vitthalrao; Patidar, Kalpana A; Parwani, Rajkumar N

2014-01-01

242

Hardness/intensity correlations among BATSE bursts  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

243

Block Sorting is Hard Wolfgang W. Bein  

E-print Network

Block Sorting is Hard Wolfgang W. Bein Lawrence L. Larmore University of Nevada, Las Vegas Department of Computer Science I. Hal Sudborough University of Texas at Dallas Department of Computer Science. #12;r 1 l 2s l 1 2 2 3 5 42 3 6 r1 4 1 34 22 61 ( x + x + x ) ( x + x + x )3 5q q q 3 4 2 2 23 l v3 4

Bein, Wolfgang

244

Hard spheres on the gyroid surface  

PubMed Central

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 Poincar 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

Dotera, Tomonari; Kimoto, Masakiyo; Matsuzawa, Junichi

2012-01-01

245

Experiments on asteroids using hard landers  

NASA Technical Reports Server (NTRS)

Hard lander missions to asteroids are examined using the Westphal penetrator study as a basis. Imagery and chemical information are considered to be the most significant science to be obtained. The latter, particularly a detailed chemical analysis performed on an uncontaminated sample, may answer questions about the relationships of asteroids to meteorites and the place of asteroids in theories of the formation of the solar system.

Turkevich, A.; Economou, T.

1978-01-01

246

Is cannabis a gateway to hard drugs?  

Microsoft Academic Search

The gateway hypothesis proposes that use of cannabis directly increases the risk of consuming hard drugs. We test this controversial,\\u000a but influential, hypothesis on a sample of cannabis users, exploiting a unique set of drug price data. A flexible approach\\u000a is developed to identify the causal gateway effect using a bivariate survival model with shared frailty estimated using a\\u000a latent

Hans Olav Melberg; Andrew M. Jones; Anne Line Bretteville-Jensen

2010-01-01

247

Hardness enhancement in nanocrystalline tantalum thin films  

SciTech Connect

Nanocrystalline tantalum thin film was prepared by radio frequency magnetron sputtering on a glass substrate. Structure and mechanical properties of the as-deposited thin film were investigated by X-ray diffraction, transmission electron microscopy, and nanoindentation. The salient feature in the present tantalum thin film with a grain size of 76.5 nm is the remarkable enhancement of hardness, about one order of magnitude higher than that of bulk coarse-grained tantalum.

Nieh, Tai-Gang [ORNL; Yang, Bing [ORNL; Zhang, Ming [ORNL; Chu, Jinn P [Taiwan National Ocean University

2006-01-01

248

Dynamic Hardness Tester and Cure Meter  

NASA Technical Reports Server (NTRS)

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.

Madigosky, Walter M.; Fiorito, Ralph B.

1993-01-01

249

Checking robust nonsingularity is NP-hard  

Microsoft Academic Search

We consider the following problem: givenk+1 square matrices with rational entries,A0,A1,...,Ak, decide ifA0+r1A1+贩+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

Svatopluk Poljak; Ji? Rohn

1993-01-01

250

Rad-Hard/HI-REL FPGA  

NASA Technical Reports Server (NTRS)

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.

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

1997-01-01

251

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

DOEpatents

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.

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

1996-01-01

252

Hard diffraction and deep inelastic scattering  

SciTech Connect

Since the advent of hard-collision physics, the study of diffractive processes - shadow physics - has been less prominent than before. However, there is now a renewed interest in the subject, especially in that aspect which synthesizes the short-distance, hard-collision phenomena with the classical physics of large rapidity-gaps. This is especially stimulated by the recent data on deep-inelastic scattering from HERA, as well as the theoretical work which relates to it. The word diffraction is sometimes used by high-energy physicists in a loose way. The author defines this term to mean: A diffractive process occurs if and only if there is a large rapidity gap in the produced-particle phase space which is not exponentially suppressed. Here a rapidity gap means essentially no hadrons produced into the rapidity gap (which operates in the {open_quotes}lego{close_quotes} phase-space of pseudo-rapidity and azimuthal angle). And non-exponential suppression implies that the cross-section for creating a gap with width {Delta}{eta} does not have a power-law decrease with increasing subenergy s=e{sup {Delta}{eta}}, but behaves at most like some power of pseudorapidity {Delta}{eta}{approx}log(s). The term hard diffraction shall simply refer to those diffractive process which have jets in the final-state phase-space.

Bjorken, J.D.

1994-04-01

253

Confined Hard Disk Two Piston System Model  

NSDL National Science Digital Library

The Confined Hard Disk Two Piston System simulates a constant-energy two-dimensional system of unit mass particles confined by two frictionless pistons of equal mass M. This computer model complements theoretical work describing the adiabatic expansion of an ideal gas using the quasi-static approximation. Users can set the number of particles N, their diameter and their initial particle kinetic energy. Slow-moving particles are color-coded as blue and fast particles are color-coded as yellow. The time evolution of temperature, pressure, and piston speed are shown in a second window. 聽 Particles in this model have unit mass and interact through contact forces. Collision times are computed analytically because particles and pistons move with constant velocity between collisions. The time evolution algorithm advances the particle position from collision to collision until the requested time step is achieved. The time evolution is then paused, data is accumulated, and the screen is redrawn. The Confined Hard Disk Two Piston System was developed using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_stp_hd_ConfinedHardDiskTwoPistonSystem.jar file will run the program if Java is installed.

Christian, Wolfgang

2011-03-09

254

Solving the hard problem of Bertrand's paradox  

NASA Astrophysics Data System (ADS)

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.

Aerts, Diederik; de Bianchi, Massimiliano Sassoli

2014-08-01

255

Hard hadronic collisions: extrapolation of standard effects  

SciTech Connect

We study hard hadronic collisions for the proton-proton (pp) and the proton-antiproton (p anti p) option in the CERN LEP tunnel. Based on our current knowledge of hard collisions at the present CERN p anti p Collider, and with the help of quantum chromodynamics (QCD), we extrapolate to the next generation of hadron colliders with a centre-of-mass energy E/sub cm/ = 10 to 20 TeV. We estimate various signatures, trigger rates, event topologies, and associated distributions for a variety of old and new physical processes, involving prompt photons, leptons, jets, W/sup + -/ and Z bosons in the final state. We also calculate the maximum fermion and boson masses accessible at the LEP Hadron Collider. The standard QCD and electroweak processes studied here, being the main body of standard hard collisions, quantify the challenge of extracting new physics with hadron colliders. We hope that our estimates will provide a useful profile of the final states, and that our experimental physics colleagues will find this of use in the design of their detectors. 84 references.

Ali, A.; Aurenche, P.; Baier, R.; Berger, E.; Douiri, A.; Fontannaz, M.; Humpert, B.; Ingelman, G.; Kinnunen, R.; Pietarinen, E.

1984-01-01

256

Characterization of Radiation Hard Silicon Materials  

SciTech Connect

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.

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

2009-02-24

257

Stopping the Brain Drain of Skilled Veteran Teachers: Retaining and Valuing Their Hard-Won Experience  

ERIC Educational Resources Information Center

Veteran educators are being encouraged to take early retirement in order to create jobs for less-experienced, lower-paid novices. Veteran educators are not alone: early retirement promotions have become the norm for aging workers in America. Consequently, there is a brain-drain of skilled workers at the national, state, and local levels. The early

Fibkins, William L.

2011-01-01

258

Fault-Tolerant, Radiation-Hard DSP  

NASA Technical Reports Server (NTRS)

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.

Czajkowski, David

2011-01-01

259

The material co-construction of hard science fiction and physics  

NASA Astrophysics Data System (ADS)

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.

Hasse, Cathrine

2014-02-01

260

Relative importance of calcium and magnesium in hardness-based modification of copper toxicity  

SciTech Connect

Because of the relationship between water hardness and the toxicity of many metals, total hardness is used as a model parameter to calculate ambient water quality criteria for copper and other metals. However, the relative contribution of the Ca and Mg components of total hardness as modifiers of metals toxicity is not considered in the water quality criteria. Acute Cu toxicity was measured in rainbow trout (Oncorhynchus mykiss) and chinook salmon (O. tshawytscha) swim-up fry in laboratory waters that were formulated to have similar total hardness and alkalinity but different Ca and Mg concentrations. Experiments were performed at nominal total hardness values of 40 and 90 mg/L (as CaCO{sub 3}). In four paired toxicity tests, acute Cu toxicity was significantly lower, i.e., 96-h LC50s were higher, in laboratory waters containing proportionately more Ca (Ca:Mg molar ratios of 1.5--5.2) than in waters containing less Ca (Ca:Mg molar ratios of 0.2--0.8). the relative increase in the 96-h Cu LC50 at higher Ca concentrations, but similar total hardness concentrations, was between 29 and 86% when the low Ca treatment was similar to American Society for Testing and Materials laboratory water. Failure to account for differences in Ca when matching or adjusting for total hardness thus exerts an important influence on the prediction of metal toxicity. These differences must be addressed in water-effect ratio testing in which paired tests with laboratory and site waters are conducted.

Welsh, P.G.; Lipton, J.; Chapman, G.A.; Podrabsky, T.L.

2000-06-01

261

New York Sea Grant's Hard Clam Research Initiative  

NSDL National Science Digital Library

This New York Sea Grant website hosts the Hard Clam Research Initiative, a program launched in October 1999 to investigate the population dynamics of hard clams in Long Island's south shore estuary. The site features links to program information, the research projects involved, facts about hard clams and the hard clam industry, a list of publications, media links, and contact information. It also includes a "What's New" column that highlights current events associated with the project.

Focazio, Paul C.; Grant, New Y.

262

Requirements specification of distributed hard real-time operating systems  

Microsoft Academic Search

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

ManSang Chung; Heonshik Shin

1991-01-01

263

February 24, 2009 Radiation-Hardness of VCSEL/PIN  

E-print Network

February 24, 2009 Radiation-Hardness of VCSEL/PIN W. Fernando, K.K. Gan, H.P. Kagan, R.D. Kass, J Introduction Radiation hardness of PINs Radiation hardness of VCSELs Summary #12;K.K. Gan ATLAS Upgrade with 50% safety factor #12;K.K. Gan ATLAS Upgrade Week 5 K.K. Gan 5 Radiation-Hardness of Silicon PIN

Gan, K. K.

264

The hardness-flow stress correlation in metallic materials  

Microsoft Academic Search

Hardness is a measure of the resistance of a material to indentation and a wide variety of indentation tests have been devised\\u000a to measure the hardness of materials. In the case of hardness tests which utilize spherical balls as the indentor, it is also\\u000a possible to derive flow stress-strain relationships from hardness tests carried out either over a range of

G Sundararajan; Y Tirupataiah

1994-01-01

265

Design of Hard Water Stable Emulsifier Systems for Petroleum-  

E-print Network

Design of Hard Water Stable Emulsifier Systems for Petroleum- and Bio-based Semi for petroleum and bio-based MWFs that improve fluid lifetime by providing emulsion stability under hard water. The newly developed petroleum and bio-based formulations with improved hard water stability are competitive

Clarens, Andres

266

Toughening of hard nanostructural thin films: a critical review  

Microsoft Academic Search

For engineering applications of thin films, appropriate combination of high hardness with other properties (such as high toughness, low residual stress, good adhesion with substrate and oxidation resistance) is of vital importance. Super high hardness alone does not have too much use. For practical application, hardness and toughness are of the same importance. This paper gives a critical review on

Sam Zhang; Deen Sun; Yongqing Fu; Hejun Du

2005-01-01

267

UNCERTAINTY EVALUATION OF THE REFERENCE HARDNESS STANDARD OF SLOVENIA  

Microsoft Academic Search

A commercial hardness testing machine has been provided to represent a reference hardness standard in Slovenia. Various hardness scales which are important for calibration purposes are realized on this machine. The evaluation of measurement uncertainty is one of the most important tasks for establishing this reference standard. Therefore the influence quantities contributing to the uncertainty are determined and the calibration

Konrad Herrmann

268

AN EMPIRICAL APPROACH TO DETERMINING ROCKWELL HARDNESS MEASUREMENT UNCERTAINTY  

Microsoft Academic Search

Characteristics of the empirically developed Rockwell hardness test make it difficult to determine measurement uncertainty using methods based on mathematical models describing the relationship between the measurand and the influence quantities. An empirical approach to determining Rockwell hardness uncertainty has been developed, which provides a method based on the familiar procedures and practices of Rockwell hardness testing laboratories. The approach

Samuel R. Low

269

ESTABLISHMENT OF A HARDNESS METROLOGICAL SYSTEM IN BRAZIL  

Microsoft Academic Search

In the present work, part of a large project, developed in partnership among INMETRO, ITUC\\/PUC- Rio and INT since 1995, to establish a national hardness metrological system in Brazil to Brinell, Vickers and Rockwell hardness scales, is presented, e.g. the development of reference blocks, for different ranges of Rockwell B and C hardness scales. These results and the installation of

J. A. Cruz; R. R. Machado; S. P. Oliveira; A. R. Martins; A. C. Vidal; J. A. S. Pereira; I. Caminha; I. Abud; C. Barbosa

270

Noncontact Human Force Capturing based on Surface Hardness Measurement  

E-print Network

Noncontact Human Force Capturing based on Surface Hardness Measurement Masahiro Fujiwara method based on skin surface hardness measurement. The measurement system is composed of an airborne ultrasound phased array and a laser displacement sensor. The surface hardness distribution of a human hand

Shinoda, Hiroyuki

271

Study of hot hardness characteristics of tool steels  

NASA Technical Reports Server (NTRS)

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.

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

1972-01-01

272

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

273

A Bayesian Approach to Hardness Ratios for non-Bayesians  

E-print Network

A Bayesian Approach to Hardness Ratios for non-Bayesians John E. Davis @space.mit.edu> December 18, 2007 1 Introduction Hardness ratios are often used in situations where there may not be enough. The computation of confidence limits for hardness ratios has been addressed by others ([Park et al.(2006), Jin et

Davis, John E.

274

Hard Bottom Substrate Monitoring Horns Rev Offshore Wind Farm  

E-print Network

#12;Hard Bottom Substrate Monitoring Horns Rev Offshore Wind Farm 2004 Survey Report No. 1 March : Simon B. Leonhard #12;Horns Rev. Hard Bottom Substrate Monitoring 2004 Survey Report No. 1. Page 3 Doc ........................................................................................................................ 15 #12;Horns Rev. Hard Bottom Substrate Monitoring 2004 Survey Report No. 1. Page 4 Doc. No. 2438

275

Hard or Soft Classification? Large-Margin Unified Machines  

E-print Network

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 on estimated probabilities. In contrast, hard classifiers directly target the classification decision boundary

Liu, Yufeng

276

MATERIALS CHARACTERISATION Material properties such as strength, toughness or hardness  

E-print Network

MATERIALS CHARACTERISATION Material properties such as strength, toughness or hardness are usually factors. This paper presents an experimental evidence that hardness of rolled martensitic steel can for the characterisation of material properties; parameters, such as elastic modulus, material microstructure, hardness etc

277

Aperiodic Task Scheduling for Hard Real-Time Systems  

Microsoft Academic Search

燗 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

Brinkley Sprunt; Lui Sha; John P. Lehoczky

1989-01-01

278

Easiness Assumptions and Hardness Tests: Trading Time for Zero Error  

Microsoft Academic Search

We propose a new approach toward derandomization in the uniform setting, where it is computationally hard to find possible mistakes in the simulation of a given probabilistic algorithm. The approach consists in combining both easiness and hardness complexity assumptions: if a derandomization method based on an easiness assumption fails, then we obtain a certain hardness test that can be used

Valentine Kabanets

2001-01-01

279

Electromagnetic Analysis of Synchronous and Asynchronous Circuits using Hard  

E-print Network

Electromagnetic Analysis of Synchronous and Asynchronous Circuits using Hard Disc Heads Theo and electromagnetic analysis (EMA) 路 Construction of different sensors for EMA 路 Differential EMA on synchronous the magnetic field component 颅 Inductive hard disc head (circa 1990) 颅 Giant magnetoresistive hard disc head

Moore, Simon

280

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 ? 2-system Charles L. Epstein and Jeremy Magland LSNI, 2005 Abstract In the hard pulse approximation, commonly used in nuclear magnetic reso- nance, one

281

Approximation Hardness of the (1; 2)-Steiner Tree Problem  

E-print Network

Approximation Hardness of the (1; 2)- Steiner Tree Problem Mathias Hauptmann #3; Abstract We give a survey on the approximation hardness of the Steiner Tree Problem. While for the general metric case to the (1,2)-Steiner Tree Problem due to Bern and Plassmann [BP89] with approximation hardness results

Eckmiller, Rolf

282

Chronic toxicity of chloride to freshwater species: effects of hardness and implications for water quality guidelines.  

PubMed

Toxicity tests using nine freshwater species (Ceriodaphnia dubia, Daphnia magna, Oncorhynchus mykiss, Pimephales promelas, Lumbriculus variegatus, Tubifex tubifex, Chironomus dilutus, Hyallela azteca, and Brachionus calyciflorus) were conducted to evaluate their sensitivity to chloride. Acute-to-chronic ratios (ACRs) from these tests indicate the ACR of 7.59 employed by the United States Environmental Protection Agency (U.S. EPA) in deriving its water quality guideline for chloride may be conservative; a revised ACR of 3.50 is presented here. The endpoints used to calculate the ACR included 24-h to 96-h median lethal concentrations (LC50s) for acute tests, and 48-h to 54-d inhibition concentration (ICx) values for growth or reproduction for chronic exposures. Data from the present chronic toxicity tests, and other investigators, were used to propose a water quality guideline for long-term exposure to chloride using a species sensitivity distribution (SSD) approach. The 5th percentile from the SSD was calculated as 307?mg/L and proposed as the water quality guideline. Cladocerans were the most sensitive species in the dataset. Ceriodaphnia dubia was used to evaluate the relationship between water hardness and sensitivity to chloride. A strong relationship was observed and was used to establish a hardness-related equation to modify the proposed water quality guideline on the basis of water hardness, resulting in values ranging from 64?mg/L chloride at 10?mg/L hardness to 388?mg/L chloride at 160?mg/L hardness (as CaCO?). These data suggest that current water quality guidelines for chloride may be overly conservative in water with moderate-to-high hardness, and may not be sufficiently protective under soft-water conditions. PMID:20872898

Elphick, James R F; Bergh, Kelli D; Bailey, Howard C

2011-01-01

283

Effect of Austenitizing Heat Treatment on the Microstructure and Hardness of Martensitic Stainless Steel AISI 420  

NASA Astrophysics Data System (ADS)

The effect of austenitizing on the microstructure and hardness of two martensitic stainless steels was examined with the aim of supplying heat-treatment guidelines to the user that will ensure a martensitic structure with minimal retained austenite, evenly dispersed carbides and a hardness of between 610 and 740 HV (Vickers hardness) after quenching and tempering. The steels examined during the course of this examination conform in composition to medium-carbon AISI 420 martensitic stainless steel, except for the addition of 0.13% vanadium and 0.62% molybdenum to one of the alloys. Steel samples were austenitized at temperatures between 1000 and 1200 癈, followed by oil quenching. The as-quenched microstructures were found to range from almost fully martensitic structures to martensite with up to 35% retained austenite after quenching, with varying amounts of carbides. Optical and scanning electron microscopy was used to characterize the microstructures, and X-ray diffraction was employed to identify the carbide present in the as-quenched structures and to quantify the retained austenite contents. Hardness tests were performed to determine the effect of heat treatment on mechanical properties. As-quenched hardness values ranged from 700 to 270 HV, depending on the amount of retained austenite. Thermodynamic predictions (using the CALPHAD model) were employed to explain these microstructures based on the solubility of the carbide particles at various austenitizing temperatures.

Barlow, L. D.; Du Toit, M.

2012-07-01

284

Vickers hardness investigation of work-hardening in used NiTi rotary instruments.  

PubMed

A contributing mechanism for clinical failure of NiTi rotary instruments might be excessive work hardening. Vickers hardness was measured with 300 gm load near the flutes in three regions (D2-D4, D6-D10, and D14 towards the shank) for nine representative clinically used ProFile GT instruments that had been axially sectioned (10 measurements in each region). Consistent values could not be obtained at D1. Minimum hardness occurred at D2 to D4, with means from 313 to 324 (SD from 7 to 16). Maximum hardness with means ranging widely from 330 to 481 was found beyond D14. Mean hardness at D2 to D4 was 320 for an as-received ProFile instrument. Because a mean Vickers hardness of 326 has been reported for a shape-memory NiTi orthodontic wire product, it can be concluded that the NiTi instruments did not experience substantial work hardening at D2 to D4 during clinical use, in agreement with previous differential scanning calorimetric analyses. PMID:17174681

Alapati, Satish B; Brantley, William A; Nusstein, John M; Daehn, Glenn S; Svec, Timothy A; Powers, John M; Johnston, William M; Guo, Wenhua

2006-12-01

285

A bias assessment for in-situ ultrasonic hardness testing of steel fasteners  

SciTech Connect

The problem of sub-standard and/or mismarked installed fasteners has received broad attention in quality control standard and largely discussed in technical publications and in public press. The Industrial Fastener Institute (IFI, 1988) released a detailed documented inspection program to ensure the delivery and the usage of appropriate fasteners, imposing mandatory traceability of the manufacturer marking and quality certification reports. For the billions of the existing installed bolts without reliable lot identification and/or quality certification, IFI recommends in-situ control using non-destructive testing and/or hardness measurements with portable testers. The ultrasonic indentation hardness (HU) with the Krautkramer portable tester--operating on the ultrasonic contact impedance method described by Kleesattel (Jankowski D.M., 1990)--is one of the more frequent equipment used in the in-situ control of steel products and machine elements. The advantages of the ultrasonic tester--low weight, direct hardness reading, easy to operate--have determined to be included also for the in-situ control of installed fasteners. However, the bias of this method was not analyzed; the practiced calibration of standard blocks is not conclusive for the comparison of the in-situ measured hardness with the standard reference value obtained using laboratory Rockwell hardness (HR) tester. The purpose of this paper is to point out the specific consistent/systematic differences between HU results and the reference standard HR, which defines the ruggedness and the bias of the ultrasonic method.

Ratiu, M.D.; Moisidis, N.T. [CALCET Co., San Leandro, CA (United States)

1996-12-31

286

K-COSPARSE PROJECTION IS NP-HARD 1 Projection Onto The k-Cosparse Set is NP-Hard  

E-print Network

K-COSPARSE PROJECTION IS NP-HARD 1 Projection Onto The k-Cosparse Set is NP-Hard Andreas M.r.t. some given matrix . It is shown that this projection problem is (strongly) NP-hard, even in the special.e., the number of nonzero entries in x. This problem is known to be strongly NP-hard, cf. [MP5] in [4]; the same

Paris-Sud XI, Universit茅 de

287

CO2 laser milling of hard tissue  

NASA Astrophysics Data System (ADS)

Drilling of bone and tooth tissue belongs to recurrent medical procedures (screw- and pin-bores, bores for implant inserting, trepanation etc.). Small round bores can be in general quickly produced with mechanical drills. Problems arise however by angled drilling, by the necessity to fulfill the drilling without damaging of sensitive soft tissue beneath the bone, or by the attempt to mill precisely noncircular small cavities. We present investigations on laser hard tissue "milling", which can be advantageous for solving these problems. The "milling" is done with a CO2 laser (10.6 ?m) with pulse duration of 50 - 100 ?s, combined with a PC-controlled galvanic beam scanner and with a fine water-spray, which helps to avoid thermal side-effects. The damaging of underlying soft tissue can be prevented through control of the optical or acoustical ablation signal. The ablation of hard tissue is accompanied with a strong glowing, which is absent during the laser beam action on soft tissue. The acoustic signals from the diverse tissue types exhibit distinct differences in the spectral composition. Also computer image analysis could be a useful tool to control the operation. Laser "milling" of noncircular cavities with 1 - 4 mm width and about 10 mm depth is particularly interesting for dental implantology. In ex-vivo investigations we found conditions for fast laser "milling" of the cavities without thermal damage and with minimal tapering. It included exploration of different filling patterns (concentric rings, crosshatch, parallel lines and their combinations), definition of maximal pulse duration, repetition rate and laser power, optimal position of the spray. The optimized results give evidences for the applicability of the CO2 laser for biologically tolerable "milling" of deep cavities in the hard tissue.

Werner, Martin; Ivanenko, Mikhail; Harbecke, Daniela; Klasing, Manfred; Steigerwald, Hendrik; Hering, Peter

2007-02-01

288

Evaluation of degree of conversion and hardness of dental composites photo-activated with different light guide tips  

PubMed Central

Objective: The aim of this study was to evaluate the degree of conversion and hardness of different composite resins, photo-activated for 40 s with two different light guide tips, fiber optic and polymer. Methods: Five specimens were made for each group evaluated. The percentage of unreacted carbon double bonds (% C?C) was determined from the ratio of absorbance intensities of aliphatic C?C (peak at 1637 cm?1) against internal standard before and after curing of the specimen: aromatic C-C (peak at 1610 cm?1). The Vickers hardness measurements were performed in a universal testing machine. A 50 gf load was used and the indenter with a dwell time of 30 seconds. The degree of conversion and hardness mean values were analyzed separately by ANOVA and Tukey抯 test, with a significance level set at 5%. Results: The mean values of degree of conversion for the polymer and fiber optic light guide tip were statistically different (P<.001). The hardness mean values were statistically different among the light guide tips (P<.001), but also there was difference between top and bottom surfaces (P<.001). Conclusions: The results showed that the resins photo-activated with the fiber optic light guide tip promoted higher values for degree of conversion and hardness. PMID:23407620

Galvao, Marilia Regalado; Caldas, Sergei Godeiro Fernandes Rabelo; Bagnato, Vanderlei Salvador; de Souza Rastelli, Alessandra Nara; de Andrade, Marcelo Ferrarezi

2013-01-01

289

Nonvolatile Rad-Hard Holographic Memory  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

290

Ultrafast switching of hard X-rays.  

PubMed

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

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

2014-03-01

291

Structural properties of dense hard sphere packings.  

PubMed

We numerically study structural properties of mechanically stable packings of hard spheres (HS), in a wide range of packing fractions 0.53 ? ? ? 0.72. Detailed structural information is obtained from the analysis of orientational order parameters, which clearly reveals a disorder-order phase transition at the random close packing (RCP) density, ?c ? 0.64. Above ?c, the crystalline nuclei form 3D-like clusters, which upon further desification transform into alternating planar-like layers. We also find that particles with icosahedral symmetry survive only in a narrow density range in the vicinity of the RCP transition. PMID:25098389

Klumov, Boris A; Jin, Yuliang; Makse, Hern醤 A

2014-09-11

292

Hydrodynamics of self-propelled hard rods  

E-print Network

Motivated by recent simulations and by experiments on aggregation of gliding bacteria, we study a model of the collective dynamics of self-propelled hard rods on a substrate in two dimensions. The rods have finite size, interact via excluded volume and their dynamics is overdamped by the interaction with the substrate. Starting from a microscopic model with non-thermal noise sources, a continuum description of the system is derived. The hydrodynamic equations are then used to characterize the possible steady states of the systems and their stability as a function of the particles packing fraction and the speed of self propulsion.

Aparna Baskaran; M. Cristina Marchetti

2007-08-17

293

Classic Nintendo Games are (NP-)Hard  

E-print Network

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.

Aloupis, Greg; Guo, Alan

2012-01-01

294

Evolutionary Algorithms for Hard Quantum Control  

E-print Network

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.

Ehsan Zahedinejad; Sophie Schirmer; Barry C. Sanders

2014-03-04

295

Escape Dynamics of Many Hard Disks  

E-print Network

Many-particle effects in escapes of hard disks from a square box via a hole are discussed in a viewpoint of dynamical systems. Starting from $N$ disks in the box at the initial time, we calculate the probability $P_{n}(t)$ for at least $n$ disks to remain inside the box at time $t$ for $n=1,2,\\cdots,N$. At early times the probabilities $P_{n}(t)$, $n=2,3,\\cdots,N-1$ are described by superpositions of exponential decay functions. On the other hand, after a long time the probability $P_{n}(t)$ decays in power $\\sim t^{-2n}$ for $n\

Tooru Taniguchi; Hiroki Murata; Shin-ichi Sawada

2014-03-26

296

The bounce hardness index of gravitational waves  

E-print Network

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.

Fumihiko Ishiyama; Ryutaro Takahashi

2010-09-03

297

Hard pion bremsstrahlung in the Coulomb region  

E-print Network

Hard high-energy pion-nucleus bremsstrahlung, $\\pi^- +A\\to\\pi^- +\\gamma +A$, is studied in the Coulomb region, i.e. the small-angle region where the nuclear scattering is dominated by the Coulomb interaction. Special attention is focussed on the possibility of measuring the pion polarizability in such reactions. We study the sensitivity to the structure of the underlying the pion-Compton amplitude through a model with $\\sigma$, $\\rho$, and a_1 exchanges. It is found that the effective energy in the virtual pion-Compton scattering is often so large that the threshold approximation does not apply.

G鰎an F鋖dt; Ulla Tengblad

2007-08-02

298

Hard Exclusive ?^0-Meson Production at COMPASS  

E-print Network

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.

H. Wollny for the COMPASS collaboration

2012-05-30

299

Evolutionary algorithms for hard quantum control  

NASA Astrophysics Data System (ADS)

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 as well as the (nongreedy) genetic-algorithm method to realize two fast quantum computing gates: a qutrit phase gate and a controlled-not gate. 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 can deliver a superior control procedure, for example, reducing the need for high time resolution.

Zahedinejad, Ehsan; Schirmer, Sophie; Sanders, Barry C.

2014-09-01

300

[DNA extraction from hard dental tissues].  

PubMed

Two different standard ways of DNA extraction (salting out and phenol-chloroform methods) were assayed in order to recovery nucleic acids from dental tissues. The DNA extracted was tested for purity by means of transverse alternating field electrophoresis (TAFE) using Saccharomyces cerevisiae chromosomes as markers. Both extraction methods give similar qualitative and quantitative results being a DNA yield from hard dental tissues approximately 30% of those extracted from the whole tooth. Our results indicate salting out as a preferable method due to its rapidity and usefulness. PMID:8510614

Avitabile, M; Dell'Osso, G; Ras, R; Tripi, F; Campagna, N E; Magr, G A; Sciacca, G; Ras, A

1993-01-01

301

Fate of Mycobacterium avium subsp. paratuberculosis in Swiss Hard and Semihard Cheese Manufactured from Raw Milk  

PubMed Central

Raw milk was artificially contaminated with declumped cells of Mycobacterium avium subsp. paratuberculosis at a concentration of 104 to 105 CFU/ml and was used to manufacture model hard (Swiss Emmentaler) and semihard (Swiss Tisliter) cheese. Two different strains of M. avium subsp. paratuberculosis were tested, and for each strain, two model hard and semihard cheeses were produced. The survival of M. avium subsp. paratuberculosis cells was monitored over a ripening period of 120 days by plating out homogenized cheese samples onto 7H10-PANTA agar. In both the hard and the semihard cheeses, counts decreased steadily but slowly during cheese ripening. Nevertheless, viable cells could still be detected in 120-day cheese. D values were calculated at 27.8 days for hard and 45.5 days for semihard cheese. The most important factors responsible for the death of M. avium subsp. paratuberculosis in cheese were the temperatures applied during cheese manufacture and the low pH at the early stages of cheese ripening. Since the ripening period for these raw milk cheeses lasts at least 90 to 120 days, the D values found indicate that 103 to 104 cells of M. avium subsp. paratuberculosis per g will be inactivated. PMID:11526024

Spahr, U.; Schafroth, K.

2001-01-01

302

Five Values of Giftedness  

ERIC Educational Resources Information Center

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

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

2011-01-01

303

Values and Creativity.  

ERIC Educational Resources Information Center

The paper discusses creativity and the creative process, cites current methods used to improve creativity in the workplace, and explains the concept of values and value systems as they relate to creativity. Values and value systems are defined; and their source, their nature and functions, and their measurement are outlined. (JDD)

Fernald, Lloyd W., Jr.

1987-01-01

304

Recent developments in hard magnetic materials  

NASA Astrophysics Data System (ADS)

Hard magnetic materials find ever-increasing uses in modern technology. Their importance is mainly in the domain of permanent magnets, but a variety of other applications is being offered to this class of materials, especially for what regards the areas of information storage, telecommunications and special electronic devices. These developments are connected to the emphasis that is more and more given to thin films having high magnetic anisotropy. The recernt advancement in the field of hard magnetic materials is among the best examples where technology depends to a great extent upon the continuous progress in the scientific knowledge. The research activity is characterized by the introduction of new classes of materials and continuous improvements in the preparation techniques both for what regards industrial processing and method for obtaining high quality materials in form of crystals, films or amorphous specimens. In this respect a special place must be reserved to rare earth transition metal compounds, a class of materals that attracted enormeous attention after the discovery by Hoffer and Strnat in 1966 of the large uniaxial magnetocrystalline anisotropy of the compound YCo5. Beside the so called 1?5 phase, other compositions of technical importance are the 2?17 and the recently discovered Nd2Fe14B, which is a real new ternary phase having tetragonal crystal structure. Great efforts have been done to gain a better understanding of the magnetic anisotropy and its relationship to the coercivity is of leading importance for a further development in this important area of magnetism.

Asti, G.

1989-03-01

305

Hard-Boiled for Hard Times in Leonardo Padura Fuentes's Detective Fiction  

ERIC Educational Resources Information Center

Focusing on Leonardo Padura Fuentes's hard-boiled fiction, this essay traces the origin and evolution of the genre in Cuba. Padura Fuentes has challenged the officially sanctioned socialist "literatura policial" that became popular in the 1970s and 1980s. creating a new model of criticism that is not afraid to confront the island's socio-economic

Song, H. Rosi

2009-01-01

306

Spreadability and Hardness of Butter. II. Some Factors Affecting Spreadability and Hardness[1] and [2  

Microsoft Academic Search

Temperature of the cream after pasteurization and that of the butter during storage and the printing procedure had the greatest influence on hardness and spreadability of butter. Storing cream at above 48 F. after pasteurization, and butter below 25 r., improved the body of butter. Editor. With the advent of competitive spreads which emphasize superior spread- ability, consumers

V. R. Huebner; L. C. Thomsen

1957-01-01

307

Allocating Hard Real-Time tasks: An NP-Hard Problem Made Easy  

Microsoft Academic Search

A distributed hard real time system can be composed from a number of communicating tasks. One of the difficulties with building such systems is the problem of where to place the tasks. In general there are P T ways of allocating T tasks to P processors, and the problem of finding an optimal feasible allocation (where all tasks meet physical

Ken Tindell; Alan Burns; Andy J. Wellings

1992-01-01

308

Enhanced stability of layered phases in parallel hard spherocylinders due to addition of hard spheres  

E-print Network

.30.Cz I. INTRODUCTION In hard particle fluids all allowed configurations have the same energy . In microphase separation the system starts sepa- rating into liquidlike regions that are rich in either spheres or rods. However, unlike bulk demixing, where rod and sphere rich regions grow until reaching macroscopic

Fraden, Seth

309

Phase equilibria in polydisperse nonadditive hard-sphere systems  

NASA Astrophysics Data System (ADS)

Colloidal particles naturally exhibit a size polydispersity that can greatly influence their phase behavior in solution. Nonadditive hard-sphere (NAHS) mixtures are simple and well-suited model systems to represent phase transitions in colloid systems. Here, we propose an analytical equation of state (EOS) for NAHS fluid mixtures, which can be straightforwardly applied to polydisperse systems. For positive values of the nonadditivity parameter ? the model gives accurate predictions of the simulated fluid-fluid coexistence curves and compressibility factors. NPT Monte Carlo simulations of the mixing properties of the NAHS symmetric binary mixture with ?>0 are reported. It is shown that the enthalpy of mixing is largely positive and overcomes the positive entropy of mixing when the pressure is increased, leading to a fluid-fluid phase transition with a lower critical solution pressure. Phase equilibria in polydisperse systems are predicted with the model by using the density moment formalism [P. Sollich , Adv. Chem. Phys. 116, 265 (2001)]. We present predictions of the cloud and shadow curves for polydisperse NAHS systems composed of monodisperse spheres and polydisperse colloid particles. A fixed nonadditivity parameter ?>0 is assumed between the monodisperse and polydisperse spheres, and a Schulz distribution is used to represent the size polydispersity. Polydispersity is found to increase the extent of the immiscibility region. The predicted cloud and shadow curves depend dramatically on the upper cutoff diameter ?c of the Schulz distribution, and three-phase equilibria can occur for large values of ?c .

Paricaud, Patrice

2008-08-01

310

Effects of hardness, chloride, and acclimation on the acute toxicity of sulfate to freshwater invertebrates.  

PubMed

The acute toxicity of sulfate to Ceriodaphnia dubia, Chironomus tentans, Hyalella azteca, and Sphaerium simile was assessed to support potential updates of Illinois (USA) sulfate criteria for the protection of aquatic life. The mean lethal concentrations to 50% of a sample population (LC50s), expressed as mg S04(-2)/L, in moderately hard reconstituted water (MHRW) were as follows: 512 mg/L for H. azteca, 2,050 mg/L for C. dubia, 2,078 mg/L for S. simile, and 14,134 mg/L for C. tentans. At constant sulfate (approximately 2,800 mg/L) and hardness (106 mg/L), survival of H. azteca was positively correlated with chloride concentration. Hardness also was found to ameliorate sodium sulfate toxicity to C. dubia and H. azteca, with LC50s for C. dubia increasing from 2,050 mg SO4(-2)/L at hardness = 90 mg/L to 3,516 mg SO4(-2)/L at hardness = 484 mg/L. Using a reformulated MHRW with a similar hardness but higher chloride concentration and different calcium to magnesium ratio than that in standard MHRW, the mean LC50 for H. azteca increased to 2,855 mg/L, and the LC50 for C. dubia increased to 2,526 mg/L. Acclimation of C. dubia to 500 and 1,000 mg SO4(-2)/L for several generations nominally increased mean LC50 values compared with those cultured in standard MHRW. PMID:16111001

Soucek, David John; Kennedy, Alan James

2005-05-01

311

Electronic and bonding analysis of hardness in pyrite-type transition-metal pernitrides  

NASA Astrophysics Data System (ADS)

Most commonly known hard transition-metal nitrides crystallize in rocksalt structure (B1). The discovery of ultraincompressible pyrite-type PtN2 10 years ago has raised a question about the cause of its exceptional mechanical properties. We answer this question by a systematic computational analysis of the pyrite-type PtN2 and other transition-metal pernitrides (MN2) with density functional theory. Apart from PtN2, the three hardest phases are found among them in the 3d transition-metal period. They are MnN2, CoN2, and NiN2, with computed Vickers hardness (HV) values of 19.9 GPa, 16.5 GPa, and 15.7 GPa, respectively. Harder than all of these is PtN2, with a HV of 23.5 GPa. We found the following trends and correlations that explain the origin of hardness in these pernitrides. (a) Charge transfer from M to N controls the length of the N-N bond, resulting in a correlation with bulk modulus, dominantly by providing Coulomb repulsion between the pairing N atoms. (b) Elastic constant C44, an indicator of mechanical stability and hardness is correlated with total density of states at EF, an indicator of metallicity. (c) Often cited monotonic variation of HV and Pugh's ratio with valence electron concentration found in rocksalt-type early transition-metal nitrides is not evident in this structure. (d) The change in M-M bond strength under a shearing strain indicated by crystal orbital Hamilton population is predictive of hardness. This is a direct connection between a specific bond and shear related mechanical properties. This panoptic view involving ionicity, metallicity, and covalency is essential to obtain a clear microscopic understanding of hardness.

Liu, Z. T. Y.; Gall, D.; Khare, S. V.

2014-10-01

312

P-Hardness of Equivalence Testing on Finite-State Processes  

Microsoft Academic Search

The paper shows a simple LOGSPACE-reduction from theboolean circuit value problem which demonstrates that, on finite labelledtransition systems, deciding an arbitrary relation which subsumes bisimulationequivalence and is subsumed by trace preorder is a polynomial-time-hard problem (and thus can not be expected to be efficiently parallelizable). By this, the result of Balczar, Gabarr6 and Sntha (1992)for bisimilarity is substantially extended.

Zdenek Sawa; Petr Jancar

2001-01-01

313

Confinement of hot, hard x-ray producing electrons in solar flares  

Microsoft Academic Search

Possible thermal models for solar, hard X-ray emission, consisting of small volumes in which the electrons are rapidly heated to 4 x 10鈦 K, are examined to determine under what conditions such models can be more efficient than nonthermal models. The primary energy-loss mechanism in these models is source expansion due to heat conduction which deviates from its classical value

D. F. Smith; C. G. Lilliequist

1979-01-01

314

Nanomechanics of hard films on compliant substrates.  

SciTech Connect

Development of flexible thin film systems for biomedical, homeland security and environmental sensing applications has increased dramatically in recent years [1,2,3,4]. These systems typically combine traditional semiconductor technology with new flexible substrates, allowing for both the high electron mobility of semiconductors and the flexibility of polymers. The devices have the ability to be easily integrated into components and show promise for advanced design concepts, ranging from innovative microelectronics to MEMS and NEMS devices. These devices often contain layers of thin polymer, ceramic and metallic films where differing properties can lead to large residual stresses [5]. As long as the films remain substrate-bonded, they may deform far beyond their freestanding counterpart. Once debonded, substrate constraint disappears leading to film failure where compressive stresses can lead to wrinkling, delamination, and buckling [6,7,8] while tensile stresses can lead to film fracture and decohesion [9,10,11]. In all cases, performance depends on film adhesion. Experimentally it is difficult to measure adhesion. It is often studied using tape [12], pull off [13,14,15], and peel tests [16,17]. More recent techniques for measuring adhesion include scratch testing [18,19,20,21], four point bending [22,23,24], indentation [25,26,27], spontaneous blisters [28,29] and stressed overlayers [7,26,30,31,32,33]. Nevertheless, sample design and test techniques must be tailored for each system. There is a large body of elastic thin film fracture and elastic contact mechanics solutions for elastic films on rigid substrates in the published literature [5,7,34,35,36]. More recent work has extended these solutions to films on compliant substrates and show that increasing compliance markedly changes fracture energies compared with rigid elastic solution results [37,38]. However, the introduction of inelastic substrate response significantly complicates the problem [10,39,40]. As a result, our understanding of the critical relationship between adhesion, properties, and fracture for hard films on compliant substrates is limited. To address this issue, we integrated nanomechanical testing and mechanics-based modeling in a program to define the critical relationship between deformation and fracture of nanoscale films on compliant substrates. The approach involved designing model film systems and employing nano-scale experimental characterization techniques to isolate effects of compliance, viscoelasticity, and plasticity on deformation and fracture of thin hard films on substrates that spanned more than two orders of compliance magnitude exhibit different interface structures, have different adhesion strengths, and function differently under stress. The results of this work are described in six chapters. Chapter 1 provides the motivation for this work. Chapter 2 presents experimental results covering film system design, sample preparation, indentation response, and fracture including discussion on the effects of substrate compliance on fracture energies and buckle formation from existing models. Chapter 3 describes the use of analytical and finite element simulations to define the role of substrate compliance and film geometry on the indentation response of thin hard films on compliant substrates. Chapter 4 describes the development and application of cohesive zone model based finite element simulations to determine how substrate compliance affects debond growth. Chapter 5 describes the use of molecular dynamics simulations to define the effects of substrate compliance on interfacial fracture of thin hard tungsten films on silicon substrates. Chapter 6 describes the Workshops sponsored through this program to advance understanding of material and system behavior.

Reedy, Earl David, Jr. (Sandia National Laboratories, Albuquerque, NM); Emerson, John Allen (Sandia National Laboratories, Albuquerque, NM); Bahr, David F. (Washington State University, Pullman, WA); Moody, Neville Reid; Zhou, Xiao Wang; Hales, Lucas (University of Minnesota, Minneapolis, MN); Adams, David Price (Sandia National Laboratories, Albuquerque, NM); Yeager,John (Washington State University, Pullman, WA); Nyugen, Thao D. (Johns Hopkins University, Baltimore, MD); Corona, Edmundo (Sandia National Laboratories, Albuquerque, NM); Kennedy, Marian S. (Clemson University, Clemson, SC); Cordill, Megan J. (Erich Schmid Institute, Leoben, Austria)

2009-09-01

315

Radiation Hardness Assurance (RHA) for Space Systems  

NASA Technical Reports Server (NTRS)

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.

Poivey, Christian; Buchner, Stephen

2007-01-01

316

Hard scattering phenomena from RHIC to LHC  

NASA Astrophysics Data System (ADS)

In the Relativistic Heavy Ion Collider era the high-pT particle emerging from hard scattering became an important tool of exploration of excited nuclear medium formed in ultra-relativistic heavy ion collisions. Discovery of anomalous suppression of high-pT particle yield [1] together with an observation of disappearance of back-to-back hadron correlation in central Au+Au collisions in 2002 [2] were the key results interpreted as a manifestation of the deconfined QCD medium in heavy ion collisions. Analysis of the high-pT particle and jet production is already a standard experimental technique providing a test bench for pQCD description of the point-like constituent scattering in p+p collisions and sensitive probes of the excited nuclear medium in A+A collisions.

Rak, Jan

2011-05-01

317

The Harding move: Opening up new horizons  

SciTech Connect

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.

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

1996-12-31

318

Radiation hardness assurances categories for COTS technologies  

SciTech Connect

A comparison of the radiation tolerance of three commercial, and one radiation hardened SRAM is presented for four radiation environments. This work has shown the difficulty associated with strictly categorizing a device based solely on its radiation response, since its category depends on the specific radiation environment considered. For example, the 3.3-V Paradigm SRAM could be considered a radiation-tolerant device except for its SEU response. A more useful classification depends on the methods the manufacturer uses to ensure radiation hardness, i.e. whether specific design and process techniques have been used to harden the device. Finally, this work has shown that burned-in devices may fail functionally as much as 50% lower in total dose environments than non-burned-in devices. No burn-in effect was seen in dose-rate upset, latchup, or SEE environments. The user must ensure that total dose lot acceptance testing was performed on burned-in devices.

Hash, G.L.; Shaneyfelt, M.R.; Sexton, F.W.; Winokur, P.S.

1997-03-01

319

Crystallization Mechanism of Hard Sphere Glasses  

NASA Astrophysics Data System (ADS)

In supercooled liquids, vitrification generally suppresses crystallization. Yet some glasses can still crystallize despite the arrest of diffusive motion. This ill-understood process may limit the stability of glasses, but its microscopic mechanism is not yet known. Here we present extensive computer simulations addressing the crystallization of monodisperse hard-sphere glasses at constant volume (as in a colloid experiment). Multiple crystalline patches appear without particles having to diffuse more than one diameter. As these patches grow, the mobility in neighboring areas is enhanced, creating dynamic heterogeneity with positive feedback. The future crystallization pattern cannot be predicted from the coordinates alone: Crystallization proceeds by a sequence of stochastic micronucleation events, correlated in space by emergent dynamic heterogeneity.

Sanz, Eduardo; Valeriani, Chantal; Zaccarelli, Emanuela; Poon, W. C. K.; Pusey, P. N.; Cates, M. E.

2011-05-01

320

Shock compression synthesis of hard materials  

SciTech Connect

The purpose of this research was to adapt the high explosives technology that was developed in conjunction with nuclear weapons programs to subjecting materials to ultra-high pressures and to explore the utility of this technique for the synthesis of hard materials. The research was conducted in collaboration with researchers at the University of Texas, Texas Tech University and Pantex (Mason and Hanger Corp.). The group designed, modeled, built, and tested a new device that allows quantitative recovery of grams of material that have been subjected to unprecedented pressures. The modeling work was done at Texas Tech and Pantex. The metal parts and material samples were made at the University of Texas, and Pantex machined the explosives, assembled the devices and conducted the detonations. Sample characterization was carried out at the University of Texas and Texas Tech.

Willson, C.G. [Univ. of Texas, Austin, TX (United States). Dept. of Chemistry

1999-03-01

321

Aging dynamics of colloidal hard sphere glasses  

NASA Astrophysics Data System (ADS)

We report the results of dynamic light scattering measurements of the coherent intermediate scattering function (ISF) of glasses of colloidal hard spheres for several volume fractions and a range of scattering vectors around the primary peak of the static structure factor. The ISF shows a clear crossover from an initial fast decay to a slower nonstationary decay. Aging is quantified in several different ways. However, regardless of the method chosen, the perfect ``aged'' glass is approached in a power law fashion. In particular the coupling between the fast and slow decays, as measured by the degree of stretching of the ISF at the crossover, also decreases algebraically with waiting time. The nonstationarity of this coupling implies that even the fastest detectable processes are themselves nonstationary.

Martinez, V. A.; Bryant, G.; van Megen, W.

2010-09-01

322

Hardness of decoding quantum stabilizer codes  

E-print Network

In this article we address the computational hardness of optimally decoding a quantum stabilizer code. Much like classical linear codes, errors are detected by measuring certain check operators which yield an error syndrome, and the decoding problem consists of determining the most likely recovery given the syndrome. The corresponding classical problem is known to be NP-complete, and a similar decoding problem for quantum codes is also known to be NP-complete. However, this decoding strategy is not optimal in the quantum setting as it does not take into account error degeneracy, which causes distinct errors to have the same effect on the code. Here, we show that optimal decoding of stabilizer codes is computationally much harder than optimal decoding of classical linear codes, it is #P.

Pavithran Iyer; David Poulin

2013-10-11

323

Using Cell Phone Keyboards Is (NP) Hard  

NASA Astrophysics Data System (ADS)

Sending text messages on cell phones which only contain the keys 0 through 9 and # and * can be a painful experience. We consider the problem of designing an optimal mapping of numbers to sets of letters to act as an alternative to the standard {2?{abc}, 3?{def}...}. Our overall goal is to minimize the expected number of buttons that must be pressed to enter a message in English. Some variations of the problem are efficiently solvable, either by being small instances or by being in P, but the most realistic version of the problem is NP hard. To prove NP-completeness, we describe a new graph coloring problem UniquePathColoring. We also provide numerical results for the English language on a standard corpus which describe several mappings that improve upon the standard one. With luck, one of these new mappings will achieve success similar to that of the Dvorak layout for computer keyboards.

Boothe, Peter

324

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.

325

What's the Value in Value-Added?  

ERIC Educational Resources Information Center

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

Duffrin, Elizabeth

2011-01-01

326

Hard scattering and QCD Fundamentals at RHIC  

E-print Network

In 1998, at the 4th QCD workshop, Rolf Baier asked me whether jets could be measured in Au+Au collisions because he had a prediction of a QCD medium-effect (energy loss via soft gluon radiation induced by multiple scattering) on color-charged partons traversing a hot-dense-medium composed of screened color-charges. I reviewed the possibilities in a talk explaining that there was a general consensus that for Au+Au central collisions at $\\sqrt{s_{NN}}=200$ GeV, leading particles are the only way to find jets because of the large particle density. The good news was that hard-scattering in p-p collisions was originally observed by the method of leading particles and that these techniques could be used to study hard-scattering and jets in Au+Au collisions. Notably, I described ``How everything you want to know about jets can be found using 2-particle correlations''. In fact, the predicted ``jet quenching'' and other new phenomena were discovered by this method. However, this past year, I had to soften the statement to {\\em almost everything} because we found by explicit calculation in PHENIX that the away-side two-particle correlation $p_{T_a}$ spectrum from a $\\pi^0$ trigger with $p_{T_t}$ is not sensitive to the fragmentation function--overturning a belief dating from the seminal paper of Feynman, Field and Fox in 1977. A new formula was derived which showed that the shape of the $p_{T_a}$ spectrum depends only on the power $n$ of the parton invariant cross section so that NLO pQCD calculations of the two particle away-side correlations are, in fact, less sensitive to the shape of the fragmentation function than calculations of the inclusive $\\pi^0$ cross section.

M. J. Tannenbaum

2008-06-02

327

Values and Health Problems  

ERIC Educational Resources Information Center

Summary of Lasswell's eight categories of human values with suggestions and examples of how this framework of values can be effectively utilized by education to produce responsible and productive citizens. (JC)

Murphy, Maribeth L.

1973-01-01

328

Criteria for Value Engineering.  

National Technical Information Service (NTIS)

Engineering techniques for broadening the scope and improving the effectiveness of existing conventional value analysis are investigated. Present value analysis practices consist of re-evaluation of product functions and remedial redesign to effect reduct...

H. R. Barton, R. E. Purvis

1967-01-01

329

The values of life.  

PubMed

In Life's Dominion Dworkin aims at defusing the controversy about abortion and euthanasia by redefining its terms. Basically it is not a dispute about the right to life, but about its value. Liberals should grant that human life has not only a personal, but also an intrinsic value; conservatives should accept the principle of toleration which requires to let people decide for themselves about matters of intrinsic value. Dworkin fails, however, to distinguish between two kinds of personal value: (1) the value of something to a person, when he actually or dispositionally desires it, or finds it pleasant; and (2) the value of something to a person, when it's objectively contributes to his well-being, as defined by reference to his personal point of view, whether or not he ever perceives it as so contributing. He also fails to distinguish between two meanings of the concept of 'intrinsic value': (3) ultimate, i.e. non-instrumental personal value of kind (2); (4) the impersonal value of something which is not good-for-anybody, but simply good, i.e. not a constituent of someone's well-being. Dworkin argues that the human fetus from conception onwards has a value, that it is not a personal value of kind (1), and therefore must be an intrinsic value. But the value of the life of the fetus is not a personal value of kind (2) either and therefore not an intrinsic value of kind (3): it is normally a constituent of the well-being of the pregnant woman, but that doesn't constitute its value, and it is not good 'for' the fetus itself in the relevant sense, because it doesn't have a personal point of view. If, however, the fetus' life is allowed to have an intrinsic value of kind (4), the conservative cannot be refuted by appeal to the principle of toleration, for this only concerns intrinsic value of kind (3). The liberal, indeed, should recognize that the fetus' life has a value, but it is neither a personal value (1) or (2), nor an impersonal value (4), but rather a relational value which gradually develops from some point substantially later than conception. PMID:11656609

Den Hartogh, Govert

1997-01-01

330

Identifying Extreme Exposure Values  

Cancer.gov

There are various perspectives on whether to exclude potentially unlikely exposure values. If the researcher chooses to do so, several approaches exist for identifying extreme values. We examined the plausibility of the reported frequencies for each food item in the NHANES 2009-10 DSQ and chose to exclude extreme values using a method that identifies them based on the actual distribution of the sample, but also minimizes the number of values excluded.

331

Comparison of structure and transport properties of concentrated hard and soft sphere fluids.  

PubMed

Using Newtonian and Brownian dynamics simulations, the structural and transport properties of hard and soft spheres have been studied. The soft spheres were modeled using inverse power potentials (V approximately r(-n), with 1n the potential softness). Although, at constant density, the pressure, diffusion coefficient, and viscosity depend on the particle softness up to extremely high values of n, we show that scaling the density with the freezing point for every system effectively collapses these parameters for n > or = 18 (including hard spheres) for large densities. At the freezing points, the long range structure of all systems is identical, when length is measured in units of the interparticle distance, but differences appear at short distances (due to the different shapes of the interaction potential). This translates into differences at short times in the velocity and stress autocorrelation functions, although they concur to give the same value of the corresponding transport coefficient (for the same density to freezing ratio); the microscopic dynamics also affects the short time behavior of the correlation functions and absolute values of the transport coefficients, but the same scaling with the freezing density works for Newtonian or Brownian dynamics. For hard spheres, the short time behavior of the stress autocorrelation function has been studied in detail, confirming quantitatively the theoretical forms derived for it. PMID:19425812

Lange, Erik; Caballero, Jose B; Puertas, Antonio M; Fuchs, Matthias

2009-05-01

332

Working With Missing Values  

Microsoft Academic Search

Less than optimum strategies for missing values can produce biasedestimates, distorted statistical power, and invalid conclusions. After reviewing traditional approaches (listwise, pairwise, and mean substitution), selected alternatives are cov- eredincludingsingleimputation,multipleimputa- tion, and full information maximum likelihood estimation. The effects of missing values are illus- tratedforalinearmodel,andaseriesofrecommen- dations is provided. When missing values cannot be avoided, multiple imputation and full informa- tion

Alan C. Acock

2005-01-01

333

Values in the Curriculum.  

ERIC Educational Resources Information Center

Teaching for values instead of knowledge would significantly change education. Could the psychosocial values of goodness, beauty, search for truth, social organization, and economics be rank ordered? Can and how should such life-survival values as health, sex, aggression and self-defense, language, and love be taught in school? (Author/SB)

Wees, W. R.

1980-01-01

334

Values and female entrepreneurship  

Microsoft Academic Search

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

Katherine Terrell; Michael Troilo

2010-01-01

335

Nonfundamentals and value returns  

Microsoft Academic Search

The study examines additions to and deletions from the Russell Value Index and the Russell 2000 Growth Index. The study documents stronger comovement in value reconstitutions relative to growth reconstitutions. This result is consistent with the hypothesis that nonfundamental comovement is related to the common factor in value stock returns. The mechanism of causality is difficult to determine, however; trade

Kevin C. H. Chiang; Kirill Kozhevnikov; Craig H. Wisen

2007-01-01

336

Values Drive the Plan  

ERIC Educational Resources Information Center

Values-integrated strategic planning provides the opportunity to clarify professional values as one envisions a future that is exciting and perhaps a bit provocative. This chapter explores the role and importance of student affairs and institutional values in strategic planning. It also looks at the historical roots of the profession and methods

Cook, Les P.

2010-01-01

337

Rate-hardness: a new performance metric for haptic interfaces  

Microsoft Academic Search

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

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

2000-01-01

338

Factors Which May Affect the Hardness of Cottonseed Cake.  

E-print Network

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...

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

1936-01-01

339

Radiation Hard AlGaN Detectors and Imager  

SciTech Connect

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.

None

2012-05-01

340

1500 Gate standard cell compatible radiation hard gate array  

Microsoft Academic Search

The G1500 gate array combines Sandia Labs' 4\\/3..mu.. CMOS silicon gate radiation hard process with a novel gate isolated standard cell compatible design for quick turnaround time, low cost, and radiation hardness. This device is hard to 5 x 10鈦 rads, utilizes a configuration that provides high packing density, and is supported on both the Daisy and Mentor workstations. This

B. D. Mills; B. D. Shafer; E. P. Melancon

1984-01-01

341

Correlation of Microwave and Hard X-Ray Spectral Parameters  

Microsoft Academic Search

We present the analysis of 27 solar flares with multiple peaks that were observed at hard X-ray and microwave wavelengths. A total of 57 simultaneous peaks were observed by BATSE (hard X-rays) and Owens Valley Radio Observatory (microwaves). Throughout the duration of a flare, its spectra at both wavelengths are fitted independently at all times. The hard X-ray spectra were

Adriana V. R. Silva; Haimin Wang; Dale E. Gary

2000-01-01

342

Orientational structure of dipolar hard-spherical colloids.  

PubMed

We have studied the orientational structure of a dipolar hard-spherical colloid on a homogeneous isotropic phase. The results are expressed as a function of the dipolar strength mu and volume fraction phi of dipolar colloids, and the refractive index of the scattering medium, n(s). The study is based on the self-correlation of the orientation density of the dipolar colloids, which is the static orientational structure factor [F(q)], where q is the wave vector. The importance of this quantity is that for very low phi values, it can be probed in a depolarized light scattering experiment. We have found that the structure of the suspension is better observed for high n(s). F(q) presents a different behavior for dilute and dense concentrations, it is also observed that the position of its minimum depends on phi. The response of a dipolar colloid due to its collective orientational behavior is also studied, using as an "ordering parameter" the static orientational structure factor at q=0[F(q=0)]. The study is performed for isochores as a function of mu. We have divided the analysis into five regimes, from very low to very high phi; values, i.e., phi=0.005 24, 0.1, 0.2, 0.35, and 0.45. Our analysis suggests that the dipolar colloid evolves to an orientationally ordered phase when the dipolar strength is increased, for all concentrations except for the lowest value case, phi=0.005 24. When phi=0.1 the dipolar colloid reaches the transition suddenly, whereas for the very low regime, the slope of F(q=0) first increases as if the dipolar colloid would evolve to an orientationally ordered phase; but near the transition the slope is inverted, resulting in a no global orientational order. Thus, our results suggest that in the very low regime a dipolar colloid may have a reentrant transition. PMID:11909051

Alarc髇-Waess, O; Diaz-Herrera, E; Gil-Villegas, A

2002-03-01

343

High temperature hardness of bulk single crystal GaN  

SciTech Connect

The hardness of single crystal GaN (gallium nitride) at elevated temperature is measured for the first time and compared with other materials. A Vickers indentation method was used to determine the hardness of crack-free GaN samples under an applied load of 0.5 N in the temperature range 20--1,200 C. The hardness is 10.8 GPa at room temperature, which is comparable to that of Si. At elevated temperatures GaN shows higher hardness than Si and GaAs. A high mechanical stability for GaN at high temperature is deduced.

Yonenaga, I.; Hoshi, T.; Usui, A.

2000-07-01

344

Mechanical Properties of Chocolate: How Hard is your Chocolate?  

NSDL National Science Digital Library

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.

2007-12-20

345

The Hard X-ray Spectral Evolution in XRBs, AGNs and ULXs  

E-print Network

We explore the relationship between the hard X-ray photon index $\\Gamma$ and the Eddington ratio (\\xi=L_{X}(0.5-25 keV)/L_{Edd}) in six XRBs. We find that different XRBs follow different anti-correlations between $\\Gamma$ and $\\xi$ when $\\xi$ is less than a critical value, while they follow the same positive correlation when $\\xi$ is larger than the critical value. This anti-correlation and positive correlation are also found in LLAGNs and QSOs respectively, and the anti-correlation and positive correlation of different XRBs roughly converge to the same point ($\\log \\xi=-2.1, \\Gamma=1.5$), which may correspond to the accretion mode transition, since that the anti-correlation and positive correlation are consistent with the prediction of ADAFs and standard disk/corona system respectively. The traditional low/hard state are divided into two parts by the cross point $\\log \\xi\\sim-2.1$, i.e., faint-hard state in the anti-correlation part and bright-hard state in the positive correlation part. The accretion process in the bright-hard state may be still the standard accretion disk as that in the high/soft state, which is consistent with that both the cold disk component and broad Fe K emission line are observed in some bright-hard state of XRBs. The ADAF is only important in the faint-hard state XRBs. Motivated by the similarities of the state transition and timing properties of the ULXs to that of XRBs, we then constrain the BH masses for seven luminous ULXs assuming that their X-ray spectral evolution is similar to that of XRBs. We find that the BH masses of these seven ULXs are around $10^{4}M_sun$, which are typical intermediate mass BHs (IMBHs). Our results are roughly consistent with the BH masses constrained from the model fitting with a multi-color disk and/or the timing properties(e.g., QPO and break frequency).

Qingwen Wu; Minfeng Gu

2008-12-17

346

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

E-print Network

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.

Qingqing Ma; Richard M. Stratt

2014-08-13

347

The influence of wheel/rail contact conditions on the microstructure and hardness of railway wheels.  

PubMed

The susceptibility of railway wheels to wear and rolling contact fatigue damage is influenced by the properties of the wheel material. These are influenced by the steel composition, wheel manufacturing process, and thermal and mechanical loading during operation. The in-service properties therefore vary with depth below the surface and with position across the wheel tread. This paper discusses the stress history at the wheel/rail contact (derived from dynamic simulations) and observed variations in hardness and microstructure. It is shown that the hardness of an "in-service" wheel rim varies significantly, with three distinct effects. The underlying hardness trend with depth can be related to microstructural changes during manufacturing (proeutectoid ferrite fraction and pearlite lamellae spacing). The near-surface layer exhibits plastic flow and microstructural shear, especially in regions which experience high tangential forces when curving, with consequentially higher hardness values. Between 1 mm and 7 mm depth, the wheel/rail contacts cause stresses exceeding the material yield stress, leading to work hardening, without a macroscopic change in microstructure. These changes in material properties through the depth of the wheel rim would tend to increase the likelihood of crack initiation on wheels toward the end of their life. This correlates with observations from several train fleets. PMID:24526883

Molyneux-Berry, Paul; Davis, Claire; Bevan, Adam

2014-01-01

348

Value, a nursing outcome.  

PubMed

This era of health care reform calls for the ability of hospitals to provide quality patient care while managing costs. Nursing practice is a key determinant of patient care quality and associated costs, or simply put, creating value. The value of nursing has been addressed by multiple qualified authors, yet there is no clear, consistent meaning of the term. Researchers and authors have developed some theoretical foundation for the concept of value, which evolved into important research questions that establish value as an important outcome that is sensitive to nursing practice. The opportunity to attend 2 sessions at the Harvard Business School on health care value has prompted the need for nursing to adapt to common thinking on health care value and establish its meaning for the nursing profession. This report summarizes the nursing literature on value, reflects on the executive education, and proposes direction for nursing leaders in education and practice. PMID:23454991

Pappas, Sharon H

2013-01-01

349

HARD CURRENCIES FOR HARD TIMES. TERROR ATTACKS AND THE CHOICE OF MONETARY ANCHORS  

Microsoft Academic Search

As terror抯 victims increase, hard currency commitments gain effectiveness in reducing inflation, and central bank independence loses its effectiveness, because terror reduces transparency and the number of veto players in domestic politics. PCSE (Panel?Corrected Standard Error) estimations of inflation are run on pooled cross?section time?series sample of 87 countries from 19752005. When the trend level rises to 100 victims annually

Tal Sadeh

2011-01-01

350

Surface Effects on Young's Modulud and Hardness of Fused Silica by Nanoindentation Study  

SciTech Connect

The surface Young's modulus (E) and hardness (H) of fused silica samples have been studied by nanoindentation. Two factors strongly affect the results of E and H. One factor is the polishing quality of the fused silica surface. Poor polishing quality produces much smaller E and H than the literature values for bulk fused silica. The second factor is surface flatness. Even for a well-polished silica surface, an "arch bridge effect" may hinder the measurements of the true values of E and H. A correction procedure is proposed to eliminate this effect, and the corrected results show substantial improvements.

Zheng, L.; Schmid, A.W.; Lambropoulos, J.C.

2007-01-24

351

Using Fundamental Measure Theory to Treat the Correlation Function of the Inhomogeneous Hard-Sphere Fluid  

E-print Network

We investigate the value of the correlation function of an inhomogeneous hard-sphere fluid at contact. This quantity plays a critical role in Statistical Associating Fluid Theory (SAFT), which is the basis of a number of recently developed classical density functionals. We define two averaged values for the correlation function at contact, and derive formulas for each of them from the White Bear version of the Fundamental Measure Theory functional, using an assumption of thermodynamic consistency. We test these formulas, as well as two existing formulas against Monte Carlo simulations, and find excellent agreement between the Monte Carlo data and one of our averaged correlation functions.

Jeff Schulte; Patrick Kreitzberg; Chris Haglund; David Roundy

2012-08-31

352

Using fundamental measure theory to treat the correlation function of the inhomogeneous hard-sphere fluid  

NASA Astrophysics Data System (ADS)

We investigate the value of the correlation function of an inhomogeneous hard-sphere fluid at contact. This quantity plays a critical role in statistical associating fluid theory, which is the basis of a number of recently developed classical density functionals. We define two averaged values for the correlation function at contact and derive formulas for each of them from the White Bear version of the fundamental measure theory functional, using an assumption of thermodynamic consistency. We test these formulas, as well as two existing formulas, against Monte Carlo simulations and find excellent agreement between the Monte Carlo data and one of our averaged correlation functions.

Schulte, Jeff B.; Kreitzberg, Patrick A.; Haglund, Chris V.; Roundy, David

2012-12-01

353

Dielectric and Hardness Measurements of Martian Analog Rocks in Support of the WISDOM Radar on ExoMars  

NASA Astrophysics Data System (ADS)

The success of the WISDOM (Water Ice and Subsurface Deposit Observation On Mars) radar in supporting the ExoMars drill to targets of opportunities and for maintaining optimal drilling capabilities is based on the complementarily of the two experiments in assessing the shallow subsurface physical properties. The dielectric properties as inverted from WISDOM wide-band ground penetrating radar radargrams, will be used to assess the ground mechanical properties as rock hardness, density and porosity which are crucial inputs for optimizing drilling operations. The main purpose of this research is to perform dielectric permittivity and hardness measurements for Martian analog rocks as a function of the Martian surface environmental parameters in an attempt to correlate between the physical and mechanical properties (i.e. dielectric constant and rock hardness) for volcanic rocks and permafrost simulating the case of the most upper layers of the Martian regolith. The implication for optimizing ExoMars drilling and sampling activities based on this correlation between the physical and mechanical properties will be discussed. We considered eight different types of volcanic rocks, for which we measured both the permittivity at the frequency band 200 to 1500 MHz and hardness over the range R= 10 to 100 using Schmidt hammer hardness tester. Based on our experimental results, the dielectric constant and hardness values ranged from (? = 1.91 to 8.09) and (R = 12.8 to 68) at the density of (? = 0.78 to 3 gm cm-3) for pumice and flood basalt respectively. Dielectric constant and rock hardness are found to increase with increasing sample density which implied a direct linear correlation between dielectric constant and rock hardness. The drill penetration rate of the previously described samples is predicted and correlated to the dielectric constant. An inverse relation between dielectric constant and drill penetration rate is concluded.

ElShafie, A.; Heggy, E.; Ciarletti, V.; Clifford, S. M.

2011-12-01

354

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

E-print Network

Bottled drinking water: water contamination from bottle materials (glass, hard PET, soft PET in glass and PET bottles demonstrates significant (Wilcoxon rank sum test, =0.05) differences in median, Nb and Cu. Antimony has a 21x higher median value in bottled water when sold in PET-bottles (0.33 vs

Filzmoser, Peter

355

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

E-print Network

Bottled drinking water: Water contamination from bottle materials (glass, hard PET, soft PET in glass and PET bottles demonstrates significant (Wilcoxon rank sum test, a = 0.05) differences in median, Nb and Cu. Antimony has a 21? higher median value in bottled water when sold in PET bottles (0.33 vs

Short, Daniel

356

Islands stretching test for measuring the fracture energy of the interface between a hard film and a soft substrate  

E-print Network

1 Islands stretching test for measuring the fracture energy of the interface between a hard filmNx islands on polyimide substrates. The delamination between island and substrate starts from the edge of the island when the applied strain reaches a critical value. As the crack tip approaches the edge, the crack

357

Pseudo hard-sphere potential for use in continuous molecular-dynamics simulation of spherical and chain molecules.  

PubMed

We present a continuous pseudo-hard-sphere potential based on a cut-and-shifted Mie (generalized Lennard-Jones) potential with exponents (50, 49). Using this potential one can mimic the volumetric, structural, and dynamic properties of the discontinuous hard-sphere potential over the whole fluid range. The continuous pseudo potential has the advantage that it may be incorporated directly into off-the-shelf molecular-dynamics code, allowing the user to capitalise on existing hardware and software advances. Simulation results for the compressibility factor of the fluid and solid phases of our pseudo hard spheres are presented and compared both to the Carnahan-Starling equation of state of the fluid and published data, the differences being indistinguishable within simulation uncertainty. The specific form of the potential is employed to simulate flexible chains formed from these pseudo hard spheres at contact (pearl-necklace model) for m(c) = 4, 5, 7, 8, 16, 20, 100, 201, and 500 monomer segments. The compressibility factor of the chains per unit of monomer, m(c), approaches a limiting value at reasonably small values, m(c) < 50, as predicted by Wertheim's first order thermodynamic perturbation theory. Simulation results are also presented for highly asymmetric mixtures of pseudo hard spheres, with diameter ratios of 3:1, 5:1, 20:1 over the whole composition range. PMID:23061853

Jover, J; Haslam, A J; Galindo, A; Jackson, G; M黮ler, E A

2012-10-14

358

Place Value Frenzy  

NSDL National Science Digital Library

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 ...

Carter, Miss

2006-11-04

359

The Value Chain  

NSDL National Science Digital Library

From Industry Week, The Value Chain is an online publication providing up-to-date information, articles, and resources on value chain management (VCM), a theory of management that considers every step of manufacturing a product, from raw materials "right down to disposing of the packaging after use." Along with feature articles and columns about value chain management, the site also contains a FAQ, which offers excellent basic advice about VCM, a New Roundup Weblog of breaking VCM news, and short research pieces.

360

Values and Prejudice  

E-print Network

is that stereotypes of Blacks reflect some violation of this value (e.g., "Blacks are lazy"). In addition, we expect PWE values to predict prejudice toward other groups that are stereotyped in PWE terms, e.g. homosexuals ("self-indulgent; unable to delay.... Using a large sample of undergraduates at the University of Kansas, we measured these values, along with prejudice toward Blacks, homosexuals and overweight people (see Biernat, Vescio, Theno, & Crandall, 1996). Each of these groups are stereotyped...

Biernat, Monica; Vescio, Theresa K.

2005-01-01

361

Value contamination avoidance devices  

NASA Technical Reports Server (NTRS)

Mechanical redesign methods were used to minimize contamination damage of conventional fluid components and a contamination separator device was developed for long term reusable space vehicles. These were incorporated into an existing 50.8 mm poppet valve and tested for damage tolerance in a full size open loop flow system with gaseous and liquid nitrogen. Cyclic and steady flow conditions were tested with particles of 125 to 420 micrometers aluminum oxide dispersed in the test fluids. Nonflow life tests (100,000 cycles) were made with two valve configurations in gaseous hydrogen. The redesigned valve had an acceptable cycle life and improved tolerance to contamination damage when the primary sealing surfaces were coated with thin coatings of hard plastic (Teflon S and Kynar). Analytical studies and flow testing were completed of four different versions of the separator. overall separation efficiencies in the 55-90% range were measured with these non-optimum configurations.

Endicott, D. L.

1975-01-01

362

Ultrasonically bonded value assembly  

NASA Technical Reports Server (NTRS)

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.

Salvinski, R. J. (inventor)

1975-01-01

363

Computational Modeling Develops Ultra-Hard Steel  

NASA Technical Reports Server (NTRS)

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.

2007-01-01

364

Dynamics of hard sphere colloidal dispersions  

NASA Technical Reports Server (NTRS)

Our objective is to perform on homogeneous, fully equilibrated dispersions the full set of experiments characterizing the transition from fluid to solid and the properties of the crystalline and glassy solid. These include measurements quantifying the nucleation and growth of crystallites, the structure of the initial fluid and the fully crystalline solid, and Brownian motion of particles within the crystal, and the elasticity of the crystal and the glass. Experiments are being built and tested for ideal microgravity environment. Here we describe the ground based effort, which exploits a fluidized bed to create a homogeneous, steady dispersion for the studies. The differences between the microgravity environment and the fluidized bed is gauged by the Peclet number Pe, which measures the rate of convection/sedimentation relative to Brownian motion. We have designed our experiment to accomplish three types of measurements on hard sphere suspensions in a fluidized bed: the static scattering intensity as a function of angle to determine the structure factor, the temporal autocorrelation function at all scattering angles to probe the dynamics, and the amplitude of the response to an oscillatory forcing to deduce the low frequency viscoelasticity. Thus the scattering instrument and the colloidal dispersion were chosen such as that the important features of each physical property lie within the detectable range for each measurement.

Zhu, J. X.; Chaikin, Paul M.; Phan, S.-E.; Russel, W. B.

1994-01-01

365

The New Hard X-ray Mission  

NASA Astrophysics Data System (ADS)

The Italian New Hard X-ray Mission (NHXM) is an evolution of the HEXIT-Sat concept, extending up to 80 keV the fine imaging capability today available only at E<10 keV, with the further addition of photoelectric imaging polarimetry. NHXM consists of four identical mirrors, with a 10 m focal length, achieved after launch by means of a deployable structure. Three of the four telescopes will have at their focus three identical spectro-imaging cameras, while a X-ray imaging polarimeter will be placed at the focus of the fourth. In order to ensure a low and stable background, NHXM will be place on a low Earth equatorial orbit. NHXM will provide a real breakthrough on a number of hot astrophysical issues, broadly falling under two main topics: i) censing the black holes in the Universe and probing the physics of accretion in the most diverse conditions; ii) investigating the particle acceleration mechanisms at work in different contexts, and the effects of radiative transfer in highly magnetized plasmas and strong gravitational fields.

Pareschi, Giovanni; Tagliaferri, Gianpiero; Argan, Andrea; Bellazzini, Ronaldo; Catalano, Osvaldo; Costa, Enrico; Cusumano, Giancarlo; Fiore, Fabrizio; Fiorini, Carlo; Malaguti, Giuseppe; Matt, Giorgio; Mereghetti, Sandro; Micela, Giuseppina; Perola, Giuseppe Cesare; Villa, Gabriele

2010-07-01

366

Hard Probes with the STAR Experiment  

E-print Network

Recent results on the use of hard probes in heavy ion collisions by the STAR experiment at RHIC are reviewed. The increased statistical reach from RHIC run 4 and utilization of the full capabilities of the STAR experiment have led to a qualitative improvement in these results. Light hadrons have been identified out to transverse momenta ($p_T$) of 12 GeV/c, allowing for clear identification of the dominant processes governing particle production in different $p_T$ windows. Clean signatures of dijets have been seen even in central Au+Au collisions. Nuclear modification factors for non-photonic electrons, predominantly from the decay of heavy-flavored hadrons, have also been measured out to $p_T$ of 8 GeV/c. For $p_T > \\sim 6$ GeV/c, inclusive spectra of all charged hadrons, including heavy-flavored ones, appear to be suppressed equally strongly (by a factor of four to five) in central Au+Au collisions relative to p+p collisions; interestingly enough, the probability of finding a hadron from a dijet partner is suppressed to this same level.

J. C. Dunlop; STAR Collaboration

2005-10-26

367

Exotic hadron production in hard exclusive reactions  

E-print Network

We consider hard exclusive production of exotic hadrons to study their internal structure. Revisiting the constituent-counting rule for the large-angle exclusive scattering, we discuss general features expected for the production cross section of exotic hadrons whose leading Fock states are given by multi-quark states other than the ordinary baryon ($qqq$) or meson ($q\\bar{q}$) states.We take the production of $\\Lambda(1405)$ as an example and propose to study its partonic configuration from the asymptotic scaling of the cross section, which is measurable at J-PARC. We also discuss the production of a pair of the light-hadrons such as $f_0(980)$s and $a_0(980)$s in $\\gamma^*\\gamma$ collisions in the framework of QCD factorization, in which the cross section is expressed as a convolution of the perturbative coefficients and the generalized distribution amplitudes (GDAs). We demonstrate how the internal structure of $f_0(980)$ or $a_0(980)$ can be explored by measuring the GDAs at $e^+e^-$ experiments such as the B-factories.

H. Kawamura; S. Kumano; T. Sekihara

2014-02-04

368

Exotic hadron production in hard exclusive reactions  

E-print Network

We consider hard exclusive production of exotic hadrons to study their internal structure. Revisiting the constituent-counting rule for the large-angle exclusive scattering, we discuss general features expected for the production cross section of exotic hadrons whose leading Fock states are given by multi-quark states other than the ordinary baryon ($qqq$) or meson ($q\\bar{q}$) states.We take the production of $\\Lambda(1405)$ as an example and propose to study its partonic configuration from the asymptotic scaling of the cross section, which is measurable at J-PARC. We also discuss the production of a pair of the light-hadrons such as $f_0(980)$s and $a_0(980)$s in $\\gamma^*\\gamma$ collisions in the framework of QCD factorization, in which the cross section is expressed as a convolution of the perturbative coefficients and the generalized distribution amplitudes (GDAs). We demonstrate how the internal structure of $f_0(980)$ or $a_0(980)$ can be explored by measuring the GDAs at $e^+e^-$ experiments such as t...

Kawamura, H; Sekihara, T

2014-01-01

369

Hard exclusive two photon processes in QCD  

E-print Network

This is a short review of some hard two-photon processes: $\\\\ a) \\,\\,\\gamma\\gamma\\to {\\overline P}_1 P_2,\\,\\, {\\overline P}_1 P_2= \\{\\pi^+\\pi^-, K^+ K^-, K_S K_S, \\pi^o\\pi^o, \\pi^o\\eta\\}\\,, \\\\ b) \\,\\,\\gamma\\gamma\\to V_1 V_2,\\,\\, V_1 V_2=\\{\\rho^o\\rho^o, \\phi\\phi, \\omega\\phi, \\omega\\omega \\},\\\\ c) \\,\\,\\gamma\\gamma\\to {\\rm baryon-antibaryon},\\\\ d) \\,\\,\\gamma^*\\gamma\\to P^o,\\,\\, P^o=\\{\\pi^o, \\eta, \\eta^\\prime, \\eta_c\\}$. The available experimental data are presented. A number of theoretical approaches to calculation of these processes is described, both those based mainly on QCD and more phenomenological (the handbag model, the diquark model, etc). Some theoretical questions tightly connected with this subject are discussed, in particular: the applications of various types of QCD sum rules, the endpoint behavior of the leading twist meson wave functions, etc.

Victor L. Chernyak; Simon I. Eidelman

2014-09-11

370

Hard exclusive two photon processes in QCD  

E-print Network

This is a short review of some hard two-photon processes: $\\\\ a) \\,\\,\\gamma\\gamma\\to {\\overline P}_1 P_2,\\,\\, {\\overline P}_1 P_2= \\{\\pi^+\\pi^-, K^+ K^-, K_S K_S, \\pi^o\\pi^o, \\pi^o\\eta\\}\\,, \\\\ b) \\,\\,\\gamma\\gamma\\to V_1 V_2,\\,\\, V_1 V_2=\\{\\rho^o\\rho^o, \\phi\\phi, \\omega\\phi, \\omega\\omega \\},\\\\ c) \\,\\,\\gamma\\gamma\\to {\\rm baryon-antibaryon},\\\\ d) \\,\\,\\gamma^*\\gamma\\to P^o,\\,\\, P^o=\\{\\pi^o, \\eta, \\eta^\\prime, \\eta_c\\}$. The available experimental data are presented. A number of theoretical approaches to calculation of these processes is described, both those based mainly on QCD and more phenomenological (the handbag model, the diquark model, etc). Some theoretical questions tightly connected with this subject are discussed, in particular: the applications of various types of QCD sum rules, the endpoint behavior of the leading twist meson wave functions, etc.

Chernyak, Victor L

2014-01-01

371

Revisiting the phase diagram of hard ellipsoids  

NASA Astrophysics Data System (ADS)

In this work, the well-known Frenkel-Mulder phase diagram of hard ellipsoids of revolution [D. Frenkel and B. M. Mulder, Mol. Phys. 55, 1171 (1985)] is revisited by means of replica exchange Monte Carlo simulations. The method provides good sampling of dense systems and so, solid phases can be accessed without the need of imposing a given structure. At high densities, we found plastic solids and fcc-like crystals for semi-spherical ellipsoids (prolates and oblates), and SM2 structures [P. Pfleiderer and T. Schilling, Phys. Rev. E 75, 020402 (2007)] for x : 1-prolates and 1 : x-oblates with x >= 3. The revised fluid-crystal and isotropic-nematic transitions reasonably agree with those presented in the Frenkel-Mulder diagram. An interesting result is that, for small system sizes (100 particles), we obtained 2:1- and 1.5:1-prolate equations of state without transitions, while some order is developed at large densities. Furthermore, the symmetric oblate cases are also reluctant to form ordered phases.

Odriozola, Gerardo

2012-04-01

372

Hard X rays of relativistic electrons accelerated in solar flares  

NASA Astrophysics Data System (ADS)

The direction and polarization degree of hard X rays (HXRs) in solar flares are studied. The continuous injection of relativistic electrons, which is implemented in powerful flares, is considered. The stationary relativistic kinetic equation is studied by using the method of expansion in terms of the Legendre polynomial and by integrating the equations for the expansion coefficients. The HXR characteristics are calculated using the bremsstrahlung relativistic cross-section for different angular and energetic electron distributions in the acceleration region. A high linear polarization degree of HXRs (35%) has been obtained for narrow (榗os6?) beams of electrons with a soft spectrum ( E -6); the polarization degree decreases with increasing quanta energy, whereas the directivity of a high-energy emission increases. This effect is absent for a nonrelativistic approximation. The considered model is applied to one of the most powerful flares in cycle 23, registered on October 28, 2003. The measured polarization degree values at relativistic energies (0.2-0.4 and 0.4-1 MeV) agree with the results achieved in the considered model when the electron energy spectrum index (? = 2.5), angular distribution part (榗os6?), and the spectrum cutoff energy ( E max = 1.3 MeV) were specified.

Kudryavtsev, I. V.; Charikov, Yu. E.

2012-12-01

373

The Role of Water Temperature in Hard Clam Aquaculture1  

E-print Network

FA151 The Role of Water Temperature in Hard Clam Aquaculture1 Kerry Weber, Leslie Sturmer, Elise of water temperature in hard clam production in Florida. A glossary of terms is provided at the end of the document. What is water temperature? Temperature is the measurement of heat in a material and is related

Florida, University of

374

Cytotoxicity of hard and soft denture lining materials.  

PubMed

The cytotoxicity of nine soft and hard lining materials (Mollosil Plus, Ufi Gel SC, Visco-gel, Molloplast-B, GC Tissue Conditioner, Vertex Rapid Simplified, GC Reline Hard, Vertex Self-Curing, Ufi Gel hard C) was evaluated using human gingival fibroblasts (HGFs). Twelve disk samples per lining material were prepared and incubated for 24, 48, 72, and 96 h. Cytotoxicity of each lining material's extract on cultured HGFs was measured using XTT assay. Data were analyzed using one-way ANOVA, post hoc Dunnett's T3 and Bonferroni tests at a significance level of p<0.05. At all incubation periods, all the hard lining materials (Vertex-SC, GC Reline Hard, Vertex-RS, and Ufi Gel hard C) showed cell viability higher than 90%. Among the soft lining materials, although there were no significant differences in cell viability among the different incubation periods for each lining material (p>0.05), autopolymerized acrylic-based GC Tissue Conditioner showed significantly lower cell viability than the other soft lining materials at each incubation period. Among the hard lining materials, there were no significant differences both among the materials and across all incubation periods for each lining material (p>0.05). In conclusion, all soft and hard liners exhibited good biocompatibility regardless of incubation time, except for GC Tissue Conditioner. PMID:23207219

Atay, Ayse; Bozok Cetintas, Vildan; Cal, Ebru; Kosova, Buket; Kesercioglu, Atilla; Guneri, Pelin

2012-01-01

375

Educating Hard of Hearing Children. Special Education in Transition 2.  

ERIC Educational Resources Information Center

Viewpoints of an audiologist, speech-language pathologist, special educator, classroom teacher, and parent are presented in the book on the implications of P.L. 94-142, the Education for All Handicapped Children Act, for hard of hearing students. In the introduction, M. Ross considers the status of many hard of hearing students, noting the

Ross, Mark, Ed.; Nober, Linda W., Ed.

376

A TE\\/TM modal solution for rectangular hard waveguides  

Microsoft Academic Search

A TE\\/TM modal solution for a longitudinally corrugated rectangular waveguide is developed. These longitudinal corrugations can be used to excite a quasi-TEM wave and form a hard waveguide by correctly choosing the impedance at the guide wall. The correctly chosen impedance is referred to as the hard boundary condition. The modal solution developed here solves the problem of longitudinal corrugations

Larry W. Epp; Daniel J. Hoppe; Daniel T. Kelley

2006-01-01

377

Amphiphilic hard body mixtures Matthias Schmidt and Christian von Ferber  

E-print Network

Amphiphilic hard body mixtures Matthias Schmidt and Christian von Ferber Institut fu篓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

Ott, Albrecht

378

Facility Location with Nonuniform Hard Capacities Martin Pal #  

E-print Network

for the Facility Location Problem with nonuniform, hard capacities. Facility location problems have received facility location problems. Linear programming techniques have proved to be very successful in solving unFacility Location with Nonuniform Hard Capacities Martin P??al # ?? Eva Tardos + Tom Wexler # Cornell

Tardos, ?va

379

Fitness distributions and GA hardness Yossi Borenstein and Riccardo Poli  

E-print Network

Fitness distributions and GA hardness Yossi Borenstein and Riccardo Poli Department of Computer a good definition of GA-Hardness. Given an instance of a problem, the objective is to estimate the performance of a GA. Despite partial successes current definitions are still unsatisfactory. In this paper we

Poli, Riccardo

380

Nanoindentation of silver-relations between hardness and dislocation structure  

Microsoft Academic Search

The depth dependence of hardness ion a well-annealed single crystal of silver has been characterized in nanoindentation experiments. The work is based on similar experiments performed by Chen and Hendrickson, but extends their results to indent depths on the nanometer scale. The hardness is generally found to increase with decreasing depth, with a rather sharp increase observed at depths indentation,

G. M. Pharr; W. C. Oliver

1989-01-01

381

PORTABLE HARDNESS TEST TECHNOLOGY FOR ASSESSING TITANIUM WELD QUALITY  

Microsoft Academic Search

Portable hardness testing technology was developed in this project and was based on an oxygen equivalent (OE) database for CP titanium weld metals. The database was created by testing the properties of full penetration autogenous welds made from a number of heats and using different welding procedures. The OE relationship for Rockwell B hardness was used to calibrate the portable

Dennis Harwig; Andy Joseph; Roger Spencer; Harvey Castner

382

ESTIMATION OF UNCERTAINTY IN ROCKWELL HARDNESS DIAMOND CONE INDENTERS  

Microsoft Academic Search

This work aims to validate the creation of a relationship between the direct and indirect calibrations of Rockwell C hardness diamond cone indenters. The resulting modelling allows the prediction of the indenters behaviour based on direct calibration. The uncertainty of indenters was obtained from the graph of uncertainty related to the Primary Hardness Standard Machine as a function of the

Jorge Trota Filho; Renato Reis Machado; S閞gio Pinheiro de Oliveira; Cl醬dio Afonso Koch; Islei Domingues da Silva

383

Metrological Characterization Of Optical Measuring System For Hardness Indenters  

Microsoft Academic Search

The verification of the geometry of Rockwell indenters has been widely studied in the past and, at the present, it is one of the most important tasks (in the uncertainty budget of hardness measurements) in discussion in many international organizations involved in the hardness field. The new measuring system designed in IMGC and developed in cooperation with AFFRI has been

Renato Affri; Giulio Barbato; Sergio Desogus; Alessandro Germak

384

Development & Performance of Hardness Testing Machine Calibration Processor  

Microsoft Academic Search

The calibration device capable of performing direct verification of both test force & indentation depth, which are fundamental elements of a Rockwell type hardness tester, was developed. This device can also carry out verification of operating conditions. In this paper, the examples of uncertainty of hardness calculated, based on uncertainty of each element, using this device are shown and the

Masaharu TSUJII; Fumihiko KOSHIMIZU; Eiji FURUTA; Kohji KOJIMA; Hirotaka HAYASHI; Hajime ISHIDA

385

Boosting and HardCore Sets Adam R. Klivans  

E-print Network

Boosting and Hard颅Core Sets Adam R. Klivans #3; Department of Mathematics MIT Cambridge, MA 02139 that is mildly inapproximable by circuits of some bounded size g, con颅 struct, from f , a new function f 0 that is highly inapprox颅 imable by all circuits of size closely related to g. Hardness amplification results

Servedio, Rocco

386

Hard loop effective theory of the (anisotropic) quark gluon plasma  

E-print Network

The generalization of the hard thermal loop effective theory to anisotropic plasmas is described with a detailed discussion of anisotropic dispersion laws and plasma instabilities. The numerical results obtained in real-time lattice simulations of the hard loop effective theory are reviewed, both for the stationary anisotropic case and for a quark-gluon plasma undergoing boost-invariant expansion.

A. Rebhan

2008-11-04

387

Hardness Analysis. Training Module 5.215.2.77.  

ERIC Educational Resources Information Center

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

Bonte, John L.; Davidson, Arnold C.

388

Easiness Assumptions and Hardness Tests: Trading Time for Zero Error  

Microsoft Academic Search

We propose a new approach towards derandomization in the uniform setting, where it iscomputationally hard to find possible mistakes in the simulation of a given probabilistic algorithm.The approach consists in combining both easiness and hardness complexity assumptions:if a derandomization method based on an easiness assumption fails, then we obtain a certainhardness test that can be used to remove error in

Valentine Kabanets

2000-01-01

389

Most stable structure for hard spheres Hans Koch,* Charles Radin,  

E-print Network

The hard sphere model is known to show a liquid-solid phase transition, with the solid expected s : 05.20.Gg, 05.10. a, 61.50.Ah, 82.70.Dd I. INTRODUCTION Computer simulations of the hard sphere model structure of that solid phase, since the model is one of the simplest possible showing both liquid and solid

Radin, Charles

390

AMORPHOUS ALLOY SURFACE COATINGS FOR HARD CHROMIUM REPLACEMENT - PHASE I  

EPA Science Inventory

Hard chromium coatings (0.25 to10 mil thick) are used extensively for imparting wear and erosion resistance to components in both industrial and military applications. The most common means of depositing hard chromium has been through the use of chromic acid baths containing ...

391

Rapid optical manufacturing of hard ceramic conformal windows and domes  

NASA Astrophysics Data System (ADS)

Hard ceramic conformal windows and domes provide challenges to the optical fabricator. The material hardness, polycrystalline nature and non-traditional shape demand creative optical fabrication techniques to produce these types of optics cost-effectively. VIBETM is a high-speed, high-pressure, conformal optical fabrication process that is capable of rapidly polishing hard ceramic materials and non-traditional shapes such as toroids and tangent ogives. This paper will overview the recent progress made to rapidly manufacture hard ceramic conformal windows and domes as well as the challenges associated with it. Results will show 10-50x increase in removal rates using the VIBE platform to polish hard ceramic materials compared to conventional methods.

DeGroote Nelson, J.; Gould, A.; Dworzanski, D.; Klinger, C.; Wiederhold, B.; Mandina, M.

2011-06-01

392

A New Class of Single Event Hard Errors  

NASA Technical Reports Server (NTRS)

This paper reports on hard errors induced by single ions in dynamic memories. For ions with atomic number below 80, hard errors in DRAMs appear to be similar to the hard errors reported in previous work on SRAMs. One feature of these hard errors is that they tend to recover gradually with time, because of annealing, and are thus partially recoverable. However, for gold ions, a second type of hard error was discovered which is not recoverable, and appears to be due to catastrophic internal shorting rather than small changes in leakage current. Thus, nonrecoverable errors will likely occur even in devices which eliminate the extreme sensitivity to leakage current that is inherent in 4-T SRAMs and DRAMs. It is important to understand the mechanism that is responsible for nonrecoverable errors, and investigate the effect of device scaling.

Swift, G. W.; Johnston, A. H.; Barnes, C. E.

1994-01-01

393

Properties of vacuum arc deposited amorphous hard carbon films  

SciTech Connect

Amorphous hard carbon films formed by vacuum arc deposition are hydrogen-free, dense, and very hard. The properties of amorphous hard carbon films depend strongly on the energy of the incident ions. A technique which is called Plasma Immersion Ion Implantation can be applied to vacuum arc deposition of amorphous hard carbon films to influence the ion energy. The authors have studied the influence of the ion energy on the elastic modulus determined by an ultrasonic method, and have measured the optical gap for films with the highest sp{sup 3} content they have obtained so far with this deposition technique. The results show an elastic modulus close to that of diamond, and an optical gap of 2.1 eV which is much greater than for amorphous hard carbon films deposited by other techniques.

Anders, S.; Anders, A.; Raoux, S. [Lawrence Berkeley Lab., CA (United States)] [and others

1995-04-01

394

Sampling from a polytope and hard-disk Monte Carlo  

NASA Astrophysics Data System (ADS)

The hard-disk problem, the statics and the dynamics of equal two-dimensional hard spheres in a periodic box, has had a profound influence on statistical and computational physics. Markov-chain Monte Carlo and molecular dynamics were first discussed for this model. Here we reformulate hard-disk Monte Carlo algorithms in terms of another classic problem, namely the sampling from a polytope. Local Markov-chain Monte Carlo, as proposed by Metropolis et al. in 1953, appears as a sequence of random walks in high-dimensional polytopes, while the moves of the more powerful event-chain algorithm correspond to molecular dynamics evolution. We determine the convergence properties of Monte Carlo methods in a special invariant polytope associated with hard-disk configurations, and the implications for convergence of hard-disk sampling. Finally, we discuss parallelization strategies for event-chain Monte Carlo and present results for a multicore implementation.

Kapfer, Sebastian C.; Krauth, Werner

2013-08-01

395

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

SciTech Connect

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.

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

396

Influence of water hardness and sulfate on the acute toxicity of chloride to sensitive freshwater invertebrates.  

PubMed

Total dissolved solids (TDS) represent the sum of all common ions (e.g., Na, K, Ca, Mg, chloride, sulfate, and bicarbonate) in freshwater. Currently, no federal water quality criteria exist for the protection of aquatic life for TDS, but because the constituents that constitute TDS are variable, the development of aquatic life criteria for specific ions is more practical than development of aquatic life criteria for TDS. Chloride is one such ion for which aquatic life criteria exist; however, the current aquatic life criteria dataset for chloride is more than 20 years old. Therefore, additional toxicity tests were conducted in the current study to confirm the acute toxicity of chloride to several potentially sensitive invertebrates: water flea (Ceriodaphnia dubia), fingernail clams (Sphaerium simile and Musculium transversum), snail (Gyraulus parvus), and worm (Tubifex tubifex), and determine the extent to which hardness and sulfate modify chloride toxicity. The results indicated a significant ameliorating effect of water hardness (calcium and magnesium) on chloride toxicity for all species tested except the snail; for example, the 48-h chloride median lethal concentration (LC50) for C. dubia at 50?mg/L hardness (977?mg Cl(-) /L) was half that at 800?mg/L hardness (1,836?mg Cl(-) /L). Conversely, sulfate over the range of 25 to 600?mg/L exerted a negligible effect on chloride toxicity to C. dubia. Rank order of LC50 values for chloride at a given water hardness was in the order (lowest to highest): S. simile?

Soucek, David J; Linton, Tyler K; Tarr, Christopher D; Dickinson, Amy; Wickramanayake, Nilesh; Delos, Charles G; Cruz, Luis A

2011-04-01

397

Hard X-Ray Emission from the Galaxy Cluster A2256.  

PubMed

After the positive detection by BeppoSAX of hard X-ray radiation up to approximately 80 keV in the Coma Cluster spectrum, we present evidence for nonthermal emission from A2256 in excess of thermal emission at a 4.6 sigma 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, which is not surprising given the complex radio morphology of the cluster central region. The spectral index of the hard tail detected by the Phoswich Detection System on board BeppoSAX is marginally consistent with that expected for the inverse Compton model. A value of approximately 0.05 礕 is derived for the intracluster magnetic field of the extended radio emission in the northern regions of the cluster, while a higher value of approximately 0.5 礕 could be present in the central radio halo, which is likely related to the hard tail detected by ASCA. PMID:10790058

Fusco-Femiano; Dal Fiume D; De Grandi S; Feretti; Giovannini; Grandi; Malizia; Matt; Molendi

2000-05-01

398

Hard X-Ray Emission from the Galaxy Cluster A2256  

NASA Astrophysics Data System (ADS)

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 4.6 ? 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, which is not surprising given the complex radio morphology of the cluster central region. The spectral index of the hard tail detected by the Phoswich Detection System on board BeppoSAX is marginally consistent with that expected for the inverse Compton model. A value of ~0.05 ?G 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 ?G could be present in the central radio halo, which is likely related to the hard tail detected by ASCA.

Fusco-Femiano, Roberto; Dal Fiume, Daniele; De Grandi, Sabrina; Feretti, Luigina; Giovannini, Gabriele; Grandi, Paola; Malizia, Angela; Matt, Giorgio; Molendi, Silvano

2000-05-01

399

Creativity and Values  

Microsoft Academic Search

Barron (1997) and Helson (1990) independently have suggested that a central element in all forms of creativity is the desire or goal to be creative, implying creativity as a core value. Based on these assertions and Schwartz's (1992) theory, we tested the prediction that creative individuals will hold a different values system than their less creative counterparts. University students (N=278)

Stephen J. Dollinger; Philip A. Burke; Nathaniel W. Gump

2007-01-01

400

The Values Manifesto Project  

ERIC Educational Resources Information Center

South Africa and Namibia, two countries building young democracies, face the task of transforming their public education systems to support the values articulated in their new constitutions. This article describes a project designed to incorporate these values into schools. A group of 50 Namibian teachers, who were enrolled in the author's

Euvrard, George

2006-01-01

401

Cognitive and Social Values.  

ERIC Educational Resources Information Center

Criticizes Hugh Lacey's separation of cognitive values and social values in discussions of the nature of science. Claims that attempting to distinguish between cognitive and social ignores crucial complexities in the development and use of knowledge. Proposes that the proper distinction be between legitimate and illegitimate reasons in science as

Machamer, Peter; Douglas, Heather

1999-01-01

402

Dominant Cultural Values  

Microsoft Academic Search

This study expands on previous work in exploring dominant cultural values portrayed in print magazine advertisements in the United States of America (U.S.) and India across and within product categories. A modified version of Cheng and Schweitzer's (1996) coding framework is used for the study. The differences and similarities in the observed frequencies of the dominant cultural values portrayed in

Durriya H. Z. Khairullah; Zahid Y. Khairullah

2003-01-01

403

Work Values across Generations  

ERIC Educational Resources Information Center

Mainstream publication discussions of differences in generational cohorts in the workplace suggest that individuals of more recent generations, such as Generation X and Y, have different work values than do individuals of the Silent and Baby Boom generations. Although extant research suggests that age may influence work values, few of the

Hansen, Jo-Ida C.; Leuty, Melanie E.

2012-01-01

404

Taxonomy, Anatomy, and Biology of theTaxonomy, Anatomy, and Biology of the Hard ClamHard Clam  

E-print Network

Taxonomy, Anatomy, and Biology of theTaxonomy, Anatomy, and Biology of the Hard ClamHard Clam Shellfish Aquaculture Extension Program Cedar Key, FLy, LNST@ufl.edu #12;TaxonomyTaxonomy Kingdom: Animalia in sediment #12;Clam Taxonomy Subclass Heterodonta 颅 clam-like with large hinge teeth Order Veneroidae

Florida, University of

405

From Hard to Reach to How to Reach: A Systematic Review of the Literature on Hard-to-Reach Families  

ERIC Educational Resources Information Center

This paper presents a review of the literature relating to hard-to-reach families which has been published over the last 12 years in the UK, USA, Canada and Australia. The purpose of the review was twofold: to gain insights to understandings of the term "hard-to-reach" within these services--education, health and social--which might be aiming to

Boag-Munroe, Gill; Evangelou, Maria

2012-01-01

406

High efficiency, radiation-hard solar cells  

SciTech Connect

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.

Ager III, J.W.; Walukiewicz, W.

2004-10-22

407

Reliability of hard plastic clad silica fibers  

NASA Astrophysics Data System (ADS)

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.

Skutnik, Bolesh J.; Spaniol, Stefan

2006-04-01

408

Associated jpsi + gamma diffractive production: the nature of Pomeron and test of hard diffractive factorization  

E-print Network

We present a study of diffractive associated jpsi + gamma production at the Fermilab Tevatron and LHC based on the Ingelman-Schlein model for hard diffractive scattering and the factorization formalism of NRQCD for quarkonia production. We find that this process (p + pbar to p + jpsi + gamma + X) can be used to probe the gluon content of the Pomeron and test the assumption of diffractive hard scattering factorization. Using the renormalized Pomeron flux factor D simeq 0.11 (0.052), the single diffractive jpsi + gamma production cross section at 4production is 0.50% (0.15%) in central region at the Tevatron (LHC) for the gluon fraction in the Pomeron f_g = 0.7, independent of the values of color-octet matrix elements.

Jia-Sheng Xu; Hong-An Peng

1998-07-02

409

State of the art techniques for preservation and reuse of hard copy electrocardiograms.  

PubMed

Baseline examinations and periodic reexaminations in longitudinal population studies, together with ongoing surveillance for morbidity and mortality, provide unique opportunities for seeking ways to enhance the value of electrocardiography (ECG) as an inexpensive and noninvasive tool for prognosis and diagnosis. We used newly developed optical ECG waveform recognition (OEWR) technique capable of extracting raw waveform data from legacy hard copy ECG recording. Hardcopy ECG recordings were scanned and processed by the OEWR algorithm. The extracted ECG datasets were formatted into a newly proposed, vendor-neutral, ECG XML data format. Oracle database was used as a repository for ECG records in XML format. The proposed technique for XML encapsulation of OEWR processed hard copy records resulted in an efficient method for inclusion of paper ECG records into research databases, thus providing their preservation, reuse and accession. PMID:14716617

Lobodzinski, Suave M; Teppner, Ulrich; Laks, Michael

2003-01-01

410

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

PubMed Central

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癈, coffee at 37癈, cola at 10癈, cola at 37癈, 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癈 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

Tuncer, Duygu; Karaman, Emel; Firat, Esra

2013-01-01

411

Professional values and nursing.  

PubMed

The values of nursing arise from a concern with human flourishing. If the desire to become a nurse is a reflection of an aspiration to care for others in need then we should anticipate that those who choose to nurse have a tendency towards the values we would normally associate with a caring profession (care, compassion, perhaps altruism, and so on). However, these values require a secure base if they are not to succumb to the corrupting pressures of the increasingly instrumental nature of the values of the institutions in which healthcare in general and nursing in particular takes place. One way of securing a base for withstanding the corrupting influences of the institution is to understand nursing as a practice in the sense in which Alasdair MacIntyre uses that term. In this brief paper I will outline ways in which the managerial imperative of meeting targets is both distorting practice and undermining nursing's values. I conclude that understanding nursing as a MacIntyrean practice provides a refuge from what might otherwise be overwhelming pressures for nurses to adopt instrumental values to the detriment of professional caring values. PMID:21061069

Sellman, Derek

2011-05-01

412

Size Effects in Nano-phase Hard Magnetic Materials  

NASA Astrophysics Data System (ADS)

This dissertation work was focused on the behavior of the hard magnetic materials in the nano-size and under confinement in special geometries. Three distinct systems have been examined carefully to see the effects of nano dimensions on the intrinsic and hard magnetic properties of these materials, namely Alnico thin films, Sm-Co and FePt nanoparticles. In our research work to study the spinodal decomposition of Alnico thin films prepared by sputtering on Si substrates, it has been discovered that Si diffuses into the films and gives rise to a new magnetically hard phase with TC=305癈. The phase formation occurs following the annealing at 900癈, which gave a room temperature coercivity 6.5 kOe. The maximum coercivity observed is approximately ten times larger than the bulk Alnico V value. The aim of the second project was to synthesize Sm-Co nanoparticles with high HC in the as-made state. During RT synthesis, 3.5 nm superparamagnetic SmCo5 nanoparticles have been successfully produced via the Cluster Beam Deposition (CBD) technique. Dispersion of the SmCo5 nanoparticles in a carbon matrix resulted in increase in both the coercivity and the blocking temperature. Room temperature coercivities as high as 12 kOe have been obtained for the first time in mono-layers of SmCo5 nanoparticles dispersed in C matrix. ?M plots showed that the interactions in the sample with closed packed particles are of exchange type, which lead to a decrease the overall effective anisotropy and coercivity according to the random-anisotropy model. For the third project of this dissertation, single crystal FCT FePt nanocubes have been successfully produced by a CBD technique without the need of post annealing. The nanocubes have a uniform size distribution with an average size of 6.5 nm. At 1 Torr, the particles have the FCT structure with an order parameter of 0.5 and a RT coercivity of 2 kOe. Further annealing increased the particle size to 20 nm and the RT coercivity to 10.2 kOe with perfect chemical ordering. In addition to these nanocubes, micron size rods with the FCT structure have been observed near the cluster gun. SEM analysis showed that these rods consist of nanoparticles with 20 nm average size. The new phase formation in the Alnico systems is important in view of the recent "rare earth problem" and may lead to alternative to rare earth materials for the development of high performance magnets. FePt and SmCo5 nanoparticles have a potential for use in the development of future high-density magnetic recording media because of their high coercivity, good shape and very narrow size distribution.

Akdogan, Ozan

413

Lessons of Diversity Learned the Hard Way  

ERIC Educational Resources Information Center

Through experiences training teachers across the country, the author gains insight into the necessity to accommodate diverse Native American learners. Sensitivity to Native American learning styles and values enables the author to better meet individual needs and learn valuable lessons in diversity. The author tells the story of her experiences

Morrison, Kathy

2009-01-01

414

Soft and Hard Adhesion Jun Young Chung  

E-print Network

cylin- drical stud, one flat end of which is coated with a high modulus thin baseplate. As the flexural film, the pull-off stress (r) depends on the elastic modulus (E) of the film and the radius (a is significantly higher than the case with thick films, and its value depends on the elastic modulus

Chaudhury, Manoj K.

415

Hard-Earned Income and Tax Compliance  

Microsoft Academic Search

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抯 endeavor, there is too much at stake to take the risk of being audited and paying a

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

416

The theory of indentation and hardness tests  

Microsoft Academic Search

A discussion is given of the indentation of ductile materials by cylindrical punches with conical heads. On the experimental side, experiments have been made with work-hardened and with annealed copper, with penetrations up to nine times the diameter of the punch. It is found that the load rises towards a maximum value which is not approached until the base of

R F Bishop; R Hill; N F Mott

1945-01-01

417

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

E-print Network

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 颅 an incremental value approach Efficiency

Ohta, Shigemi

418

Low hardness organisms: Culture methods, sensitivities, and practical applications  

SciTech Connect

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.

DaCruz, A.; DaCruz, N.; Bird, M.

1995-12-31

419

Synthesis and characterization of hard/soft bimagnetic nanoparticles  

NASA Astrophysics Data System (ADS)

Bimagnetic nanoparticles are synthesized from high-temperature solution method by growing soft magnetic phases on a hard magnetic phase. The hard phase is chosen as the FePt phase and the soft phases include Fe3O4, CoFe2O4 and FeCo. The soft phases can be coated or attached to the hard phase by changing reaction conditions. When the soft phases are coated on the hard phase, core/shell structured bimagnetic nanoparticles are formed; when the soft phases are attached to the hard phase, brick-like bimagnetic nanoparticles are formed. Magnetic properties of these nanoparticles are affected by dimensions of the soft and hard components due to the exchange coupling between them. Upon reductive annealing, an assembly of the bimagnetic nanoparticles is transformed into a hard magnetic nanocomposite with enhanced energy product which is 35% higher than single FePt phase. With proper choice of materials and dimension of both phases, these bimangetic nanoparticles may be used as building blocks for novel functional nanomaterials for various applications.

Nandwana, Vikas; Shankar Chaubey, Girija; Yano, Kazuaki; Liu, J. Ping

2007-03-01

420

Working with Missing Values  

ERIC Educational Resources Information Center

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

Acock, Alan C.

2005-01-01

421

Place Value Made Simple  

NSDL National Science Digital Library

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.

Service, National S.

2009-05-19

422

Graphically Modeling Stakeholder Values  

NASA Astrophysics Data System (ADS)

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.

Stone, Harold L.

2002-08-01

423

Savings Bonds Value Calculator  

NSDL National Science Digital Library

From the Federal Reserve Bank of New York, this site computes the redemption value of users's US savings bonds. Easy-to-use pull-down menus allow visitors to enter information such as the date of issue and face value of their Series E bonds, Series EE bonds, and Series S bonds. After entering the information, the Calculator will then show a chart of issue dates and denominations and actual worth of the bonds, if cashed within a set period of time.

424

Relative Value Function Approximation  

Microsoft Academic Search

A form of temporal difference learning is presented that learns the relative utility of states,instead of the absolute utility. This formulation backs up decisions instead of values, makingit possible to learn a simpler function for defining a decision-making policy. A nonlinearrelative value function can be learned without increasing the dimensionality of the inputs.Contents1 Introduction 12 Approximating Absolute Utility 13 Approximating

Doina Precup; Paul E. Utgoff

1997-01-01

425

The Expanding Place Value  

NSDL National Science Digital Library

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.

Thomson, Erin; Pugh, Dana

2005-01-01

426

Professional values and nursing  

Microsoft Academic Search

The values of nursing arise from a concern with human flourishing. If the desire to become a nurse is a reflection of an aspiration\\u000a to care for others in need then we should anticipate that those who choose to nurse have a tendency towards the values we\\u000a would normally associate with a caring profession (care, compassion, perhaps altruism, and so

Derek Sellman

2011-01-01

427

Reduced hardness as an indicator of susceptibility of timbers to attack by Euophryum confine Broun  

Microsoft Academic Search

The influence of early-wood hardness on the tunnelling activity of Euophryum confine Broun (Coleoptera: Curculionidae) is reported. The hardness of Pinus nigra (Arnold) sapwood blocks was measured using a micro-hardness testing device that simulated a mandible. Hardness was influenced by moisture content and wood decay. Hardness was found to be significantly lower at 25% equilibrium moisture content than at 15%

M. Green; H. D. Mansfield-Williams; A. J. Pitman

2004-01-01

428

AeSPoe HARD ROCK LABORATORY  

SciTech Connect

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.

Svemar, C; Pettersson, S.; Hedman, T.

2003-02-27

429

Connection between micro and macro hardness pearlitic-ferritic steel  

NASA Astrophysics Data System (ADS)

Many physical and mechanical properties of materials are closely related to their microstructure, technologies to control the microstructure of materials have been well developed to obtain suitable properties. We measured the volume fraction of perlite and ferrite, micro Vickers hardness in pearlite and ferrite and macro hardness using different sample with different carbon content. The volume fraction of pearlite increases by increasing carbon content. By increasing carbon content, micro and macro hardness increase. We can conclude that for those conditional the mixing rule can't be use.

Duka, Edlira; Oettel, Heinrich; Dilo, Teuta

2012-09-01

430

The determination of yield strength from hardness measurements  

Microsoft Academic Search

It is shown that the 0.2 pct offset yield strength of a material (in kg per sq mm) can be obtained from simple hardness measurements\\u000a using the expression ?\\u000a y\\u000a = (H\\/3)(0.1)\\u000a m-2\\u000a , whereH is the Diamond pyramid hardness andm is Meyer抯 hardness coefficient. This expression holds for brass, steel in either the cold rolled or tempered condition,\\u000a and

J. R. Cahoon; W. H. Broughton; A. R. Kutzak

1971-01-01

431

Hard X-ray properties of magnetic cataclysmic variables  

Microsoft Academic Search

Hard X-ray surveys have proven remarkably efficient in detecting intermediate\\u000apolars and asynchronous polars, two of the rarest type of cataclysmic variable\\u000a(CV). Here we present a global study of hard X-ray selected intermediate polars\\u000aand asynchronous polars, focusing particularly on the link between hard X-ray\\u000aproperties and spin\\/orbital periods. To this end, we first construct a new\\u000asample of

S. Scaringi; A. J. Bird; A. J. Norton; C. Knigge; A. B. Hill; D. J. Clark; A. J. Dean; V. A. McBride; E. J. Barlow; L. Bassani; A. Bazzano; M. Fiocchi; R. Landi

2009-01-01

432

[Detection of tofu hardness by near infrared spectroscopy].  

PubMed

The possibility of determination of tofu hardness by near infrared spectroscopy (NIR, 833-2500 nm) was studied. The influences of water content and protein content on the spectra were discussed, in order to detect the hardness. The models of Tofu hardness were calibrated by partial least squares regression (PLS) after eliminating outline, spectra pretreatment, and wavelength optimization (r = 0.994, RMSEC = 0.391%, RMSEP = 0.416%, RSD = 2.27%). All of the results were better than those by sense assessing method. PMID:17020029

Han, Dong-Hai; Lu, Chao; Wen, Zhao-Hui; Geng, Zhao-Xi

2006-07-01

433

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

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

434

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

SciTech Connect

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.

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

435

Effect of water hardness on surface tension and dilational visco-elasticity of sodium dodecyl sulphate solutions.  

PubMed

The complementary drop and bubble profile analysis and maximum bubble pressure tensiometry are used to measure the dynamic surface tension of aqueous SDS solutions in the presence of hardness salts (CaCl(2) and MgCl(2) in the ratio of 2:1 at concentrations of 6 and 40FH). The presence of hardness salts results in an essential increase of the SDS adsorption activity, which indicates the formation of Ca(DS)(2) and Mg(DS)(2) in the SDS solutions. The surface tension isotherms of SDS in presence of Ca(DS)(2) and Mg(DS)(2) are described using the generalised Frumkin model. The presence of hardness salts accelerates the ageing of SDS solutions as compared with the addition of 0.01 M NaCl due to a faster hydrolysis and hence formation of dodecanol. These results are used to estimate the possible concentration of dodecanol in the studied SDS solutions. The buoyant bubble profile method with harmonic surface oscillations is used to measure the dilational rheology of SDS solutions in presence of hardness salts in the frequency range between 0.005 Hz and 0.2 Hz. The visco-elasticity modulus in the presence of hardness salts is higher as compared with its values in the presence of 0.01 M NaCl additions. The ageing of SDS solutions leads to an essential increase of the visco-elastic modulus. PMID:22484167

Fainerman, V B; Lylyk, S V; Aksenenko, E V; Kovalchuk, N M; Kovalchuk, V I; Petkov, J T; Miller, R

2012-07-01

436

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)

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.

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

2007-12-01

437

Relative value health insurance.  

PubMed

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

Korobkin, Russell

2014-04-01

438

From Here the Beginning is Hard to Find: Stories  

E-print Network

From Here the Beginning is Hard to Find, a collection of inter-related short stories, centers around the feelings of loss, both culturally and personally, that result from assimilation in America. The collection follows ...

Lang, Jameelah Jafaar

2010-04-26

439

Chemical bonding in hard boron-nitride multilayers  

SciTech Connect

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.

Jankowski, A.F.; Hayes, J.P.

1997-06-01

440

Innovation incentives and competition in the hard disk drive industry  

E-print Network

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 ...

Wu, Xiaohua Sherry

2011-01-01

441

How to estimate hardness of crystals on a pocket calculator  

SciTech Connect

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.

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

442

Nanoindentation hardness anisotropy of alumina crystal: A molecular dynamics study  

E-print Network

Nanoindentation hardness anisotropy of alumina crystal: A molecular dynamics study Kenji Nishimura nanoindentation are studied by molecular dynamics simulations for three surface orientations of alumina crystal metallurgical engineering to opto- and microelectronics. Nanoindentation is widely used to examine mechanical

Southern California, University of

443

Prepulse dependence in hard x-ray generation from microdroplets  

SciTech Connect

We report on experiments which show that liquid microdroplets are very efficient in hard x-ray generation. We make a comparative study of hard x-ray emission from 15 {mu}m methanol microdroplets and a plain slab target of similar atomic composition at similar laser intensities. The hard X-ray yield from droplet plasmas is about 35 times more than that obtained from solid plasmas. A prepulse that is about 10ns and at least 2% in intensity of the main pulse is essential for hard x-ray generation from the droplets at about 1015 W cm-2. A hot electron temperature of 36 keV is measured from the droplets at 8 x 1014 W cm-2; three times higher intensity is needed to obtain similar hot electron temperature from solid plasmas that have similar atomic composition. We use 1D-PIC simulation to obtain qualitative correlation to the experimental observations.

Anand, M.; Kahaly, S.; Kumar, G. Ravindra [Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005 (India); Sandhu, A. S. [JILA, University of Colorado, Boulder CO 80303 (United States); Gibbon, P. [John-von-Neumann Institute for Computing, ZAM, Forschungszentrum, Juelich, D-52425 Germany (Germany); Krishnamurthy, M. [Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005 (India); Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany)

2006-04-07

444

Remote hard copy. Volume 2. Operating manual. [Versatec 1110A  

SciTech Connect

Procedures for operating the remote hard copy plotters are presented. Initializing the system, caring for the plotter, and interacting with the system are all covered. Descriptions of error conditions and how to operate diagnostics are presented.

Simons, R.W.

1980-03-01

445

The Hardness Distribution of Gamma-Ray Bursts  

E-print Network

It is often stated that gamma-ray bursts (GRBs) have typical energies of several hundreds $\\keV$, where the typical energy may be characterized by the hardness H, the photon energy corresponding to the peak of $\

Ehud Cohen; Tsvi Piran; Ramesh Narayan

1997-10-07

446

Flattening fixed-angle chains is strongly NP-hard  

E-print Network

Planar configurations of fixed-angle chains and trees are well studied in polymer science and molecular biology. We prove that it is strongly NP-hard to decide whether a polygonal chain with fixed edge lengths and angles ...

Demaine, Erik D.

447

Improving the polishing process for Rockwell hardness test block  

E-print Network

Inefficiencies in a Rockwell hardness test block manufacturing process were analyzed. The polishing stage was identified to be the bottleneck with a high reworking rate. An understanding based on the physics of polishing ...

Imani Nejad, Mohammad

2009-01-01

448

21 CFR 133.148 - Hard grating cheeses.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Hard grating cheeses. 133.148 Section 133.148 Food and Drugs...SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION CHEESES AND RELATED CHEESE PRODUCTS Requirements for Specific...

2010-04-01

449

Hard ellipses: Equation of state, structure, and self-diffusion.  

PubMed

Despite their fundamental and practical interest, the physical properties of hard ellipses remain largely unknown. In this paper, we present an event-driven molecular dynamics study for hard ellipses and assess the effects of aspect ratio and area fraction on their physical properties. For state points in the plane of aspect ratio (1 ? k ? 9) and area fraction (0.01 ? ? ? 0.8), we identify three different phases, including isotropic, plastic, and nematic states. We analyze in detail the thermodynamic, structural, and self-diffusive properties in the formed various phases of hard ellipses. The equation of state (EOS) is shown for a wide range of aspect ratios and is compared with the scaled particle theory (SPT) for the isotropic states. We find that SPT provides a good description of the EOS for the isotropic phase of hard ellipses. At large fixed ?, the reduced pressure p increases with k in both the isotropic and the plastic phases and, interestingly, its dependence on k is rather weak in the nematic phase. We rationalize the thermodynamics of hard ellipses in terms of particle motions. The static structures of hard ellipses are then investigated both positionally and orientationally in the different phases. The plastic crystal is shown to form for aspect ratios up to k = 1.4, while appearance of the stable nematic phase starts approximately at k = 3. We quantitatively determine the locations of the isotropic-plastic (I-P) transition and the isotropic-nematic (I-N) transition by analyzing the bond-orientation correlations and the angular correlations, respectively. As expected, the I-P transition point is found to increase with k, while a larger k leads to a smaller area fraction where the I-N transition takes place. Moreover, our simulations strongly support that the two-dimensional nematic phase in hard ellipses has only quasi-long-range orientational order. The self-diffusion of hard ellipses is further explored and connections are revealed between the structure and the self-diffusion. We discuss the relevance of our results to the glass transition in hard ellipses. Finally, the results of the isodiffusivity lines are evaluated for hard ellipses and we discuss the effect of spatial dimension on the diffusive dynamics of hard ellipsoidal particles. PMID:23862947

Xu, Wen-Sheng; Li, Yan-Wei; Sun, Zhao-Yan; An, Li-Jia

2013-07-14

450

Value of space defenses  

SciTech Connect

This report discusses the economic value of defenses against Near-Earth Object (NEO) impacts is bounded by calculating expected losses in their absence, which illustrates the contributions from NEOs of different sizes and the sensitivity of total expected losses to impact frequencies. For typical size distributions and damage of only a few decades duration, losses are most sensitive to small NEOs, and lead to defenses worth a few $M/yr. When the persistence of damage with NEO size is taken into account, that shifts the loss to the largest NEOs and greatly increases expected loss and values.

Canavan, G.H.

1992-10-29

451

Wetlands Functions and Values  

NSDL National Science Digital Library

This learning module on wetland functions and values is the newest addition to the EPA's Watershed Academy Website. The module explores the ecological and societal benefits and values that wetlands provide, such as "fish and wildlife habitats, natural water quality improvement, flood storage, shoreline erosion protection, opportunities for recreation and aesthetic appreciation," and much more. First-time users will find helpful instructions at "How to navigate this module;" the hyperlinked instructional text is also accompanied by useful color images. For anyone interested in wetland ecology, there is much to be learned (or reviewed) here.

2007-07-30

452

Wetlands Functions and Values  

NSDL National Science Digital Library

This learning module on wetland functions and values is the newest addition to the EPA's Watershed Academy Website (first reviewed in the January 19, 2000 Scout Report for Science & Engineering). The module explores the ecological and societal benefits and values that wetlands provide, such as "fish and wildlife habitats, natural water quality improvement, flood storage, shoreline erosion protection, opportunities for recreation and aesthetic appreciation," and much more. First-time users will find helpful instructions at "How to navigate this module;" the hyperlinked instructional text is also accompanied by useful color images. For anyone interested in wetland ecology, there is much to be learned (or reviewed) here.

2001-01-01

453

Heat treatment optimization in the manufacture of Wilson Rockwell steel hardness test blocks  

E-print Network

The heat-treatment process in the manufacture of Wilson Rockwell steel hardness test blocks often produces parts which are inconsistent in the mean hardness and hardness uniformity. In this thesis, the sources of variation ...

Tan, Vincent Tandean

2009-01-01

454

Debris-bed friction of hard-bedded glaciers  

USGS Publications Warehouse

[1] Field measurements of debris-bed friction on a smooth rock tablet at the bed of Engabreen, a hard-bedded, temperate glacier in northern Norway, indicated that basal ice containing 10% debris by volume exerted local shear traction of up to 500 kPa. The corresponding bulk friction coefficient between the dirty basal ice and the tablet was between 0.05 and 0.08. A model of friction in which nonrotating spherical rock particles are held in frictional contact with the bed by bed-normal ice flow can account for these measurements if the power law exponent for ice flowing past large clasts is 1. A small exponent (n < 2) is likely because stresses in ice are small and flow is transient. Numerical calculations of the bed-normal drag force on a sphere in contact with a flat bed using n = 1 show that this force can reach values several hundred times that on a sphere isolated from the bed, thus drastically increasing frictional resistance. Various estimates of basal friction are obtained from this model. For example, the shear traction at the bed of a glacier sliding at 20 m a-1 with a geothermally induced melt rate of 0.006 m a-1 and an effective pressure of 300 kPa can exceed 100 kPa. Debris-bed friction can therefore be a major component of sliding resistance, contradicting the common assumption that debris-bed friction is negligible. Copyright 2005 by the American Geophysical Union.

Cohen, D.; Iverson, N.R.; Hooyer, T.S.; Fischer, U.H.; Jackson, M.; Moore, P.L.

2005-01-01

455

Hard X-ray emission from X-ray bursters  

Microsoft Academic Search

Hard X-ray emission from compact objects has been considered a spectral signature of black hole candidates. However, SIGMA and BATSE recently detected transient emission in the energy range 30-200keV from several X-ray bursters (XRBs) believed to contain weakly magnetized neutron stars. At least seven XRBs (including Aquila X-1 and 4U 1608-52) are currently known to produce erratic hard X-ray outbursts

M. Tavani; E. Liang

1996-01-01

456

Integrating Multimedia Applications in Hard Real-Time Systems  

Microsoft Academic Search

This paper focuses on the problem of providing efficient run-time support to multimedia applications in a real-time system, where two types of tasks can coexist simultaneously: multimedia soft real-time tasks and hard real-time tasks. Hard tasks are guaranteed based on worst case execution times and minimum interarrival times, whereas multimedia and soft tasks are served based on mean parameters. The

Luca Abeni; Giorgio C. Buttazzo

1998-01-01

457

Elasticity of a polydisperse hard-sphere crystal  

E-print Network

A general Monte Carlo simulation method of calculating the elastic constants of polydisperse hard-sphere colloidal crystal was developed. The elastic constants of a size polydisperse hard sphere fcc crystal is calculated. The pressure and three elastic constants(C11, C12 and C44) increase significantly with the polydispersity. It was also found from extrapolation that there is a mechanical terminal polydispersity above which a fcc crystal will be mechanically unstable.

Mingcheng Yang; Hongru Ma

2008-06-19

458

Palaeoecology and evolution of marine hard substrate communities  

NASA Astrophysics Data System (ADS)

Marine organisms have occupied hard substrates since the Archaean. Shells, rocks, wood and sedimentary hardgrounds offer relatively stable habitats compared to unconsolidated sediments, but the plants and animals which inhabit them must develop means to gain and defend this premium attachment space. Hard substrate communities are formed by organisms with a variety of strategies for adhering to and/or excavating the substrates they inhabit. While mobile grazers, organically attached and even soft-bodied organisms may leave evidence of their former presence in ancient hard substrate communities, a superior fossil record is left by sessile encrusters with mineralised skeletons and by borers which leave trace fossils. Furthermore, encrusters and borers are preserved in situ, retaining their spatial relationships to one another and to the substrate. Spatial competition, ecological succession, oriented growth, and differential utilisation of exposed vs. hidden substrate surfaces can all be observed or inferred. Hard substrate communities are thus excellent systems with which to study community evolution over hundreds of millions of years. Here we review the research on modern and ancient hard substrate communities, and point to some changes that have affected them over geological time scales. Such changes include a general increase in bioerosion of hard substrates, particularly carbonate surfaces, through the Phanerozoic. This is, at least in part, analogous to the infaunalisation trends seen in soft substrate communities. Encrusting forms show an increase in skeletalisation from the Palaeozoic into the Mesozoic and Cenozoic, which may be a response to increasing levels of predation. Hard substrate communities, considering borers and encrusters together, show a rough increase in tiering through the Phanerozoic which again parallels trends seen in soft substrate communities. This extensive review of the literature on living and fossil hard substrate organisms shows that many opportunities remain for large-scale studies of trends through time at the community and clade levels. Palaeontologists will especially benefit by closer integration of their work with that of neontologists, particularly in aspects of ecology such as larval recruitment, competition and succession.

Taylor, P. D.; Wilson, M. A.

2003-07-01

459

Hardness of T-carbon: Density functional theory calculations  

Microsoft Academic Search

We reconsider and interpret the mechanical properties of the recently proposed allotrope of carbon, T-carbon [Sheng , Phys. Rev. Lett.PRLTAO0031-900710.1103\\/PhysRevLett.106.155703 106, 155703 (2011)], using density functional theory in combination with different empirical hardness models. In contrast with the early estimation based on Gao 's model, which attributes to T-carbon a high Vickers hardness of 61 GPa comparable to that of

Xing-Qiu Chen; Haiyang Niu; Cesare Franchini; Dianzhong Li; Yiyi Li

2011-01-01

460

Stochastic model of a dense spinless hard-sphere gas  

Microsoft Academic Search

Summary牋The motion of a spinless quantum particle subjected to random hard-sphere scatterings is studied in the framework of stochastic\\u000a mechanics. The result is applied to the case of a generic particle of a dense spinless hard-sphere gas leading to a description\\u000a that displays the competition between the thermal and the quantum noise. Finally, the model is discussed in connection with

L. M. Morato; G. Galilei

1991-01-01

461

Recent results in the hard-tube MILO experiment  

Microsoft Academic Search

Summary form only given, as follows. The hard-tube MILO (magnetically insulated transmission line oscillator) is an all stainless steel, brazed version of the gigawatt-class, L-band tube reported by Calico et al. (1995). The Calico MILO generated a 1.5-GW, 60-ns FWHM microwave pulse using a 500-kV, 60-kA, 500-ns electron beam, while the hard-tube MILO generates a 1.8-GW, 170-ns FWHM microwave pulse

M. Haworth; K. Hendrick; T. Englert; D. Shiffler; K. Hackett; R. Lemke; M. Sena; K. Allen; D. Ralph; D. Henley

1997-01-01

462

Tricriticality of Interacting Hard Squares: Some Exact Results  

NASA Astrophysics Data System (ADS)

Baxter has solved a restricted class of square lattice gas models with nearest-neighbor exclusion (thus "hard squares") and next-nearest-neighbor interactions. Arguments are presented which demonstrate that the subspace spanned by his exact solution contains the line of tricritical points and the associated surface of first-order transitions of hard squares with attractive next-nearest-neighbor interactions. The tricritical exponents so identified confirm those obtained by Nienhuis for a dilute Ising model.

Huse, David A.

1982-10-01

463

Abradability and hardness in rare-earth-oxide stabilized hafnia  

Microsoft Academic Search

The dry abradability and diamond pyramid hardness of HfO2 fully-stabilized by variable additions of Er2O3 were determined on sintered polycrystalline specimens of near-theoretical densities. Measurements on fused silica and on a single crystal of Y2O3-stabilized ZrO2 were included for comparison. In general, the hardness was decreased and the abradability was increased by increasing additions of stabilizing oxide. These effects were

C. D. Wirkus; M. F. Berard

1982-01-01

464

New X-ray lasers schemes - Toward the hard radiation  

Microsoft Academic Search

Possibilities for creating an active medium for hard X-ray lasers using superbright (intensity in excess of 10 exp 17 W\\/sq cm) laser radiation pumping are examined. Several possible X-ray laser schemes are evaluated, and their advantages and disadvantages discussed. It is shown that an inner ionization type scheme is particularly promising for the realization of hard X-ray lasers.

V. V. Korobkin; M. Yu. Romanovskij

1992-01-01

465

The wear of ultrafine WC朇o hard metals  

Microsoft Academic Search

The wear performance of ultrafine-grained tungsten carbide朿obalt (WC朇o) hard metals during three-body abrasion and particle erosion has been evaluated and compared to that of similar conventional coarser grained hard metals. The tungsten carbide grain size varied between 0.5 and 3?m with cobalt contents ranging from 6 to 15%. Silica particles were used in both forms of testing. Erosion was carried

C. Allen; M. Sheen; J. Williams; V. A. Pugsley

2001-01-01

466

Hardness and Deformation Properties of Solids at Very High Temperatures  

Microsoft Academic Search

This paper describes an experimental study of the deformation and strength properties of refractory solids at temperatures up to 2000^circC. It is difficult to make direct stress-strain measurements at elevated temperatures on small specimens of these materials, and consequently the strength property measured was indentation hardness. The problem of obtaining an indenter that is sufficiently hard and stable at these

A. G. Atkins; D. Tabor

1966-01-01

467

Hard thermal effective action in QCD through the thermal operator  

E-print Network

Through the application of the thermal operator to the zero temperature retarded Green's functions, we derive in a simple way the well known hard thermal effective action in QCD. By relating these functions to forward scattering amplitudes for on-shell particles, this derivation also clarifies the origin of important properties of the hard thermal effective action, such as the manifest Lorentz and gauge invariance of its integrand.

Ashok Das; J. Frenkel

2007-03-08

468

Common sense and hard decision analysis: why might they conflict?  

Microsoft Academic Search

Purpose Hard decision analysis models allow complex decisions to be broken down into easier-to-handle and precisely defined sub-problems and also provide a documented rationale for the decision. This paper aims to investigate why the course of action prescribed by a hard decision analysis model can sometimes conflict with a manager's common-sense view of the appropriate course of action, even

Paul Goodwin

2009-01-01

469

The Hard X-Ray Sky: Recent Observational Progress  

NASA Technical Reports Server (NTRS)

The last fifty years have witnessed the birth, development, and maturation to full potential of hard X-ray astrophysics. The primary force driving the history of the field has been the development of space-based instrumentation optimized for getting the maximum science out of observations of high-energy photons from astrophysical sources. Hard X-ray telescopes are leading research in areas such as galactic diffuse emission, galactic transients, and active galactic nuclei.

Gehrels, Neil; Cannizzo, John K.

2010-01-01

470

New component of hard X-rays in solar flares  

Microsoft Academic Search

We present high resolution (approx.1 keV FWHM) spectral measurements from 13 to 300 keV of a solar flare hard X-ray burst observed on 1980 June 27 by a balloon-borne array of cooled germanium planar detectors. At energies below approx.35 keV we identify a new component of solar flare hard X-rays. This component is characterized by an extremely steep spectrum which

R. P. Lin; R. A. Schwartz; R. M. Pelling; K. C. Hurley

1981-01-01

471

Dc power supplies and hard-tube power conditioning systems  

SciTech Connect

In this lecture, we shall discuss some of the major characteristics of dc power supplies and hard-tube pulsers, along with many of their PCS limiting properties and several of the more powerful vacuum tubes that are currently available for larger hard-tube pulsers systems. The initial topic will be elementary dc power supplies, operating with standard 60 Hz AC input power. The full-wave bridge design will be discussed in detail, illustrating the majority of the significant circuit parameters.

Sarjeant, W.J.

1980-01-01

472

Perpendicular recording media for hard disk drives  

NASA Astrophysics Data System (ADS)

Perpendicular recording technology has recently been introduced in hard disk drives for computer and consumer electronics applications. Although conceptualized in the late 1970s, making a product with perpendicular recording that has competing performance, reliability, and price advantage over the prevalent longitudinal recording technology has taken about three decades. One reason for the late entry of perpendicular recording is that the longitudinal recording technology was quite successful in overcoming many of its problems and in staying competitive. Other reasons are the risks, problems, and investment needed in making a successful transition to perpendicular recording technology. Iwasaki and co-workers came up with many inventions in the late 1970s, such as single-pole head, CoCr alloy media with a perpendicular anisotropy, and recording media with soft magnetic underlayers [S. Iwasaki and K. Takemura, IEEE Trans. Magn. 11, 1173 (1975); S. Iwasaki and Y. Nakamura, IEEE Trans. Magn. 14, 436 (1978); S. Iwasaki, Y. Nakamura, and K. Ouchi, IEEE Trans. Magn. 15, 1456 (1979)]. Nevertheless, the research on perpendicular recording media has been intense only in the past five years or so. The main reason for the current interest comes from the need to find an alternative technology to get away from the superparamagnetic limit faced by the longitudinal recording. Out of the several recording media materials investigated in the past, oxide based CoCrPt media have been considered a blessing. The media developed with CoCrPt-oxide or CoCrPt -SiO2 have shown much smaller grain sizes, lower noise, and larger thermal stability than the perpendicular recording media of the past, which is one of the reasons for the success of perpendicular recording. Moreover, oxide-based perpendicular media have also overtaken the current longitudinal recording media in terms of better recording performance. Several issues that were faced with the soft underlayers have also been solved by the use of antiferromagnetically coupled soft underlayers and soft underlayers that are exchange coupled with an antiferromagnetic layer. Significant improvements have also been made in the head design. All these factors now make perpendicular recording more competitive. It is expected that the current materials could theoretically support areal densities of up to 500-600Gbits/in.2. In this paper, the technologies associated with perpendicular recording media are reviewed. A brief background of magnetic recording and the challenges faced by longitudinal recording technology are presented first, followed by the discussions on perpendicular recording media. Detailed discussions on various layers in the perpendicular recording media and the recent advances in these layers have been made. Some of the future technologies that might help the industry beyond the conventional perpendicular recording technology are discussed at the end of the paper.

Piramanayagam, S. N.

2007-07-01

473

Approximate resolution of hard numbering problems  

SciTech Connect

We present a new method for estimating the number of solutions of constraint satisfaction problems. We use a stochastic forward checking algorithm for drawing a sample of paths from a search tree. With this sample, we compute two values related to the number of solutions of a CSP instance. First, an unbiased estimate, second, a lower bound with an arbitrary low error probability. We will describe applications to the Boolean Satisfiability problem and the Queens problem. We shall give some experimental results for these problems.

Bailleux, O.; Chabrier, J.J. [CRID Universite de Bourgogne, Dijon (France)

1996-12-31

474

R-values  

SciTech Connect

I'll try to keep this short and simple. R{sub LANL} = (beta cpm of X{sub exp} on system 'A')/ (beta cpm of {sup 99}Mo{sub exp} on system 'A')/ (beta cpm of X on system 'A', from thermal on {sup 235}U)/ (beta cpm of {sup 99}Mo on system 'A', from thermal on {sup 235}U). As I understand it, the above equation is the historical (as well as current) way of determining R-values using data from beta counting at LANL. The ratio in the denominator, a little 'r', is the 'baseline' or 'calibration' value for a specific beta detector. Over time, if the detector 'drifts' one would see a variation in this 'r' during a thermal calibration measurement. This baseline is what LANL likes to track to monitor specific detector performance - this is not relevant to LLNL where gamma detection is used for determining R-values. LANL states that uncertainty is only dependent upon the count statistics for the isotopes measured. If one tries to convert this to an atom basis, the uncertainties will increase due to the incorporation of the uncertainties in the nuclear data used to convert the cpm to atoms. LLNL switched to gamma detection methods in the 1970s thus replacing our beta counting effort. The equation below is how we have since determined R-values. The numerator ratios atom values of isotopes that are determined by measuring gamma cpm (usually? using several peaks per isotope) and then converting to particle decay in dpm using detector efficiency for each peak and the appropriate branch ratio for each gamma emission. Isotope decay is then converted to atoms using specific activity, mass or volume?, and Avogadro's number. The denominator is simply the ratio of published, cumulative fission product chain yields for isotopes produced in a thermal irradiation on 235U - values of England & Ryder are used by LLNL for the NTNF program. Uncertainties in LLNL R-values are dependent upon gamma counting statistics as well as the nuclear data for each isotope. R{sub LLNL} = (Atoms of X{sub exp})/(Atoms of {sup 99}Mo{sub exp})/(Cumulative Fission Chain Yield of X, from thermal on {sup 235}U)/(Cumulative Fission Chain Yield of {sup 99}Mo, from thermal on {sup 235}U). The next page tabulates fission chain yields and 'atoms per gram' amounts measured in a recent NTNF Thermal Calibration. The R-values in the table are calculated using the LLNL method of determining R. The measure of success is demonstrated by how close to 1.00 the R-value is when determined during a Thermal Calibration. A value of 1.00 is the desired value. In the example below, only four isotopes lie outside of 1.00 by more than 3 percent. These are the four isotopic measurements that obviously need to be improved.

Roberts, K

2009-03-03

475

Continuous hard x-ray imager for astrophysics  

NASA Astrophysics Data System (ADS)

CHIP -- the continuous hard x-ray imager for astrophysics) -- is a powerful hard x ray imaging spectroscopy mission, an order of magnitude more sensitive to hard x rays than XTE, comprised of the large uniform coverage imager (LUCY) for all-sky coverage and the deep extragalactic survey imager (DESI) for more sensitive pointed observations. Both instrument complements will utilize the room temperature semiconductor CdZnTe in mosaiced arrays of position sensitive devices in conjunction with coded masks. Each unit will provide imaging from 2 - 100 keV with approximately 1 keV energy resolution throughout the entire energy range and few arcminute intrinsic spatial resolution. LUCY will provide (1) a complete flux- limited sample of the hard x-ray contents of our galaxy as well as of the extragalactic sky, (2) alarms and precise positions for transient phenomena on all timescales from seconds to days, and (3) continuous spectral/temporal studies of these objects over a vast range of timescales from seconds to days, to months, to years. DESI will extend LUCY's coverage even deeper by viewing a small portion of the hard x-ray sky (0.01 sr) for background limited studies of individual objects considerably deeper than present or future hard x-ray instruments.

Rothschild, Richard E.; Matteson, James L.; Heindl, W.; Peterson, Lawrence E.; Hink, Paul L.

1995-09-01

476

Mongoose: Creation of a Rad-Hard MIPS R3000  

NASA Technical Reports Server (NTRS)

This paper describes the development of a 32 Bit, full MIPS R3000 code-compatible Rad-Hard CPU, code named Mongoose. Mongoose progressed from contract award, through the design cycle, to operational silicon in 12 months to meet a space mission for NASA. The goal was the creation of a fully static device capable of operation to the maximum Mil-883 derated speed, worst-case post-rad exposure with full operational integrity. This included consideration of features for functional enhancements relating to mission compatibility and removal of commercial practices not supported by Rad-Hard technology. 'Mongoose' developed from an evolution of LSI Logic's MIPS-I embedded processor, LR33000, code named Cobra, to its Rad-Hard 'equivalent', Mongoose. The term 'equivalent' is used to infer that the core of the processor is functionally identical, allowing the same use and optimizations of the MIPS-I Instruction Set software tool suite for compilation, software program trace, etc. This activity was started in September of 1991 under a contract from NASA-Goddard Space Flight Center (GSFC)-Flight Data Systems. The approach affected a teaming of NASA-GSFC for program development, LSI Logic for system and ASIC design coupled with the Rad-Hard process technology, and Harris (GASD) for Rad-Hard microprocessor design expertise. The program culminated with the generation of Rad-Hard Mongoose prototypes one year later.

Lincoln, Dan; Smith, Brian

1993-01-01

477

Manufacture, microstructure and mechanical properties of Wsbnd Tasbnd N nano-structured hard films  

NASA Astrophysics Data System (ADS)

W1-xTaxNy (x = 0-0.95) hard films were deposited on Si substrates using reactive direct current magnetron sputtering. The effect of tantalum concentration on phase composition, microstructure, surface morphology, adhesion strength, and hardness of the films has been studied by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, atomic force microscopy, nano-indenter, and scratch tester. It was found that regardless of tantalum concentration all the W1-xTaxNy films show face centered cubic structure, and form Wsbnd Tasbnd N solid solution. The hardness and Youngs' modulus of W1-xTaxNy films initially increase and then decrease with increasing tantalum concentration, after passing the maximum value of 38 GPa and 360 GPa at x = 0.31, respectively. The adhesion strength of coating to silicon substrate is in the range of 27-35 N, no obvious variation trend of adhesion strength with tantalum concentration was observed.

Yang, J. F.; Jiang, Y.; Yuan, Z. G.; Wang, X. P.; Fang, Q. F.

2012-08-01

478

Value of Information Lotteries  

Microsoft Academic Search

The essence of decision-making is understanding the economic impact of uncertainty. In this paper a previous discussion of information value theory is extended to illustrate how the availability of information on the uncertain factors of a problem affects the probability density function of profit, the profit lottery. A bidding problem serves to demonstrate the type of calculations required and their

Ronald Howard

1967-01-01

479

Valuing Higher Education  

ERIC Educational Resources Information Center

The question of the value of higher education is today set in the context of an unprecedented banking and financial crisis. In this context of fundamental change and financial realignment, it is important that we as members of the university remake our case for why the university deserves to be considered alongside all those other worthy causes

Pillay, Gerald J.

2009-01-01

480

The value of health  

PubMed Central

Background A major problem in cost-effectiveness studies is where to draw the line between interventions which are cost-effective and those who are not. Lacking a notion about the value of a QALY, all ultimate values to the cost-effectiveness ratio are essentially arbitrary. Methods This paper presents a simple empirical model to estimate the compensating income variation of diseases and health problems. The model is estimated using data for the Netherlands. Results The compensating income variation is between 20,000 and 90,000. This is higher than most of the ultimate values used by policy-makers to decide whether an intervention is cost-effective. Our figures are roughly similar to those found in studies about the value of a statistical life year. Conclusion Estimates on the compensating income variation of diseases and health problems may provide useful information on the maximum acceptable cost-effectiveness ratio of medical interventions than those currently used by policy makers. PMID:18578854

Groot, Wim; Brink, Henriette Maassen van den

2008-01-01

481

Making People Feel Valued.  

ERIC Educational Resources Information Center

Suggests many quick, easy and inexpensive ways to help make staff members of student publications feel valued and keep staff motivation levels high. Includes additional articles that describe how an editor can support efforts to motivate, suggest that staff retreats lead to success, note how banquets serve as reward, and suggest some favorite

Fergueson, Susan; Aimone, Logan

2002-01-01

482

Biomedical value conflict.  

PubMed

Diversity among Scandinavian countries' policies on such biomedical issues as prenatal diagnosis, artificial insemination, and reimbursement for treatment provided by a foreign country illustrates the powerful influence of cultural context on bioethics and underscores the need for tolerance of the moral autonomy of nations governed by a pragmatic set of conditions for the management of value conflict. PMID:11650805

Tranoy, Knut Erik

1988-01-01

483

Fuzzy present value  

Microsoft Academic Search

Investors are constantly confronted with deciding between a multitude of different investments. The characteristics, especially the estimated return, of each alternative is never precisely known. In this paper, we propose to use fuzzy present values to model this uncertainty. We extend previous work with the possibility to account for uncertain project durations, which become increasingly important for long-term projects. The

Thomas Baerecke; Bernadette Bouchon-Meunier; Marcin Detyniecki

2011-01-01

484

Transfinite mean value interpolation  

Microsoft Academic Search

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

Christopher Dyken; Michael S. Floater

2009-01-01

485

Technostress and Library Values.  

ERIC Educational Resources Information Center

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)

Gorman, Michael

2001-01-01

486

Mean value coordinates  

Microsoft Academic Search

We derive a generalization of barycentric coordinates which allows a vertex in a planar triangulation to be expressed as a convex combination of its neighbouring vertices. The coordinates are motivated by the Mean Value Theorem for harmonic functions and can be used to simplify and improve methods for parameterization and morphing.

Michael S. Floater

2003-01-01

487

Economic Value of Veterinary  

E-print Network

Economic Value of Veterinary Diagnostics Public Investment in Animal Health Testing Yields Economic Diagnostic Laboratory (TVMDL) works to protect animal and human health through diagnostic testing of samples of animals and products. In 2007, TVMDL performed 708,300 tests in support of $65.4 million in interstate

488

Psychotherapy and religious values  

Microsoft Academic Search

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

Allen E. Bergin

1980-01-01

489

Valuing Differentiated Instruction  

ERIC Educational Resources Information Center

It is not enough to declare that differentiated instruction is going to be the order of the day. It also is not enough to call in a consultant and have teachers listen to a presentation about product, process, and assessment paradigms. Differentiated instruction is a practice that grows out of certain values that are important in the way school

Benjamin, Amy

2006-01-01

490

Whose Religious Values?  

ERIC Educational Resources Information Center

Public schools, since their founding in America in 1647, have reflected the demographic characteristics of the communities in which they are located. Because the United States has, until recently, been mostly Protestant Christian, many schooling practices have built upon the values of this faith. Pupils have sung Christmas songs at Christmas

Marshall, Joanne M.

2008-01-01

491

Radiology's value chain.  

PubMed

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 bri