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Sample records for vickers hardness tester

  1. Hardness Tester for Polyur

    Science.gov (United States)

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

    1987-01-01

    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.

  2. The Influence of Indenter Rotation Angle on The Quality of Vicker Tester Calibration

    Directory of Open Access Journals (Sweden)

    Jozef Petrík

    2011-10-01

    Full Text Available The object of submitted work is to analyze the influence of the rotation of the indenter (diamond pyramid and test force on the result of Vickers hardness tester calibration using uncertainty analysis, Measurement systems analysis (MSA, analysis of variance (ANOVA and Z-score. The rotation anmgle of indenter affects the values of hardness, repeatability rrel, maximal error Erel and relative expanded uncertainty Urel. The significance of the angle of indenter on the hardness and observed parameters of calibration no such as it of test force, but not negligible.

  3. Design of Vickers Hardness Loading Controller

    Directory of Open Access Journals (Sweden)

    Sihai Zhao

    2014-09-01

    Full Text Available Traditionally Vickers testing needs manual works, as a result, it will induce low precision and automatization. So this paper design a new type of loading controlling system, it is based on single chip computer 89S52, used PZT as the force generator in micro Vickers hardness testing. It primarily includes the designing of hardware, software of collecting data and PZT signals by AD667. This article has given the sketch of electrical circuit and controlling software, it also offers the experiment data. The experiments have showed that using this system can exactly control the loading results, and the average tolerance is less than 0.43 %.

  4. A finger-like hardness tester based on the contact electromechanical impedance of a piezoelectric bimorph cantilever.

    Science.gov (United States)

    Fu, Ji; Li, Faxin

    2015-10-01

    We proposed a finger-like hardness tester based on the electromechanical impedance of a piezoelectric bimorph cantilever. A Vickers indenter was fabricated to the free end of the bimorph to contact the sample. The contact force was monitored by a strain gauge and the contact area was obtained by tracking the bimorph's resonance frequency. The bimorph-sample contact system was modeled by the electromechanical equivalent circuit method. Verification experiments on standard hardness samples were conducted and the measured hardness values agreed well with those given by a conventional Vickers hardness tester. Further hardness measurement on a gear wheel showed that the proposed hardness tester is very adaptive and can be used for inner surface testing or in situ testing, where other hardness testers may not be applicable. The proposed hardness tester can be regarded as an improved ultrasonic hardness tester.

  5. Standard hardness conversion tables for metals relationship among brinell hardness, vickers hardness, rockwell hardness, superficial hardness, knoop hardness, and scleroscope hardness

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 Conversion Table 1 presents data in the Rockwell C hardness range on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, Knoop hardness, and Scleroscope hardness of non-austenitic steels including carbon, alloy, and tool steels in the as-forged, annealed, normalized, and quenched and tempered conditions provided that they are homogeneous. 1.2 Conversion Table 2 presents data in the Rockwell B hardness range on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, Knoop hardness, and Scleroscope hardness of non-austenitic steels including carbon, alloy, and tool steels in the as-forged, annealed, normalized, and quenched and tempered conditions provided that they are homogeneous. 1.3 Conversion Table 3 presents data on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, and Knoop hardness of nickel and high-nickel alloys (nickel content o...

  6. Dynamic Hardness Tester and Cure Meter

    Science.gov (United States)

    Madigosky, Walter M.; Fiorito, Ralph B.

    1993-01-01

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

  7. Calibrated atomic force microscope measurements of vickers hardness indentations and tip production and characterisation for scanning tunelling microscope

    DEFF Research Database (Denmark)

    Jensen, Carsten P.

    Calibrated atomic force microscope measurements of vickers hardness indentations and tip production and characterisation for scanning tunelling microscope......Calibrated atomic force microscope measurements of vickers hardness indentations and tip production and characterisation for scanning tunelling microscope...

  8. On the Invariance of Hardness at Vickers Indentation of Pre-Stressed Materials

    Directory of Open Access Journals (Sweden)

    Per-Lennart Larsson

    2017-07-01

    Full Text Available The influence from residual surface stresses on global indentation properties, i.e., hardness and size of the contact area, have been studied quite frequently in recent years. A fundamental assumption when evaluating such tests is that the material hardness is independent of any residual stresses. This assumption has been verified in the case of cone indentation of classical Mises elastoplastic materials. However, a detailed investigation of this feature in the case of three-dimensional indentation, i.e., Vickers and Berkovic indentation, has not been presented previously. It is therefore the aim of the present study to remedy this shortcoming using finite element methods. The numerical results pertinent to Vickers indentation clearly show that the material hardness is independent of residual (or applied stresses (also in case of three-dimensional indentation problems. The limitations of the validity of hardness invariance are also discussed in some detail.

  9. Changes in Vickers hardness during the decomposition of bone: Possibilities for forensic anthropology.

    Science.gov (United States)

    Walden, Steven J; Evans, Sam L; Mulville, Jacqui

    2017-01-01

    The purpose of this study was to determine how the Vickers hardness (HV) of bone varies during soft tissue putrefaction. This has possible forensic applications, notably for determining the postmortem interval. Experimental porcine bone samples were decomposed in surface and burial deposition scenarios over a period of 6 months. Although the Vickers hardness varied widely, it was found that when transverse axial hardness was subtracted from longitudinal axial hardness, the difference showed correlations with three distinct phases of soft tissue putrefaction. The ratio of transverse axial hardness to longitudinal axial hardness showed a similar correlation. A difference of 10 or greater in HV with soft tissue present and signs of minimal decomposition, was associated with a decomposition period of 250 cumulative cooling degree days or less. A difference of 10 (+/- standard error of mean at a 95% confidence interval) or greater in HV associated with marked decomposition indicated a decomposition period of 1450 cumulative cooling degree days or more. A difference of -7 to +8 (+/- standard error of mean at a 95% confidence interval) was thus associated with 250 to 1450 cumulative cooling degree days' decomposition. The ratio of transverse axial HV to longitudinal HV, ranging from 2.42 to 1.54, is a more reliable indicator in this context and is preferable to using negative integers These differences may have potential as an indicator of postmortem interval and thus the time of body deposition in the forensic context. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  10. Influence of the final temperature of investment healting on the tensile strength and Vickers hardness of CP Ti and Ti-6Al-4V alloy

    Directory of Open Access Journals (Sweden)

    Pedro César Garcia Oliveira

    2007-02-01

    Full Text Available The aim of the work was to evaluate the influence of the temperature of investment healting on the tensile strength and Vickers hardness of CP Ti and Ti-6Al-4V alloy casting. Were obtained for the tensile strength test dumbbell rods that were invested in the Rematitan Plus investment and casting in the Discovery machine cast. Thirty specimens were obtained, fiftten to the CP Titanium and fifteen to the Ti-6Al-4V alloy, five samples to each an of the three temperatures of investment: 430ºC (control group, 480ºC and 530ºC. The tensile test was measured by means of a universal testing machine, MTS model 810, at a strain of 1.0 mm/min. After the tensile strenght test the specimens were secctioned, embedded and polished to hardness measurements, using a Vickers tester, Micromet 2100. The means values to tensile tests to the temperatures 430ºC, 480 and 530: CP Ti (486.1 - 501.16 - 498.14 -mean 495.30 MPa and Ti-6Al-4V alloy (961.33 - 958.26 - 1005.80 - mean 975.13 MPa while for the Vickers hardness the values were (198.06, 197.85, 202.58 - mean 199.50 and (352.95, 339.36, 344.76 - mean 345.69, respectively. The values were submitted to Analysis of Variance (ANOVA and Tukey,s Test that indicate differences significant only between the materials, but not between the temperature, for both the materias. It was conclued that increase of the temperature of investment its not chance the tensile strength and the Vickers hardness of the CP Titanium and Ti-6Al-4V alloy.

  11. Effect of dry cryogenic treatment on Vickers hardness and wear resistance of new martensitic shape memory nickel-titanium alloy

    National Research Council Canada - National Science Library

    Vinothkumar, Thilla Sekar; Kandaswamy, Deivanayagam; Prabhakaran, Gopalakrishnan; Rajadurai, Arunachalam

    2015-01-01

    The aim of this study is to investigate the role of dry cryogenic treatment (CT) temperature and time on the Vickers hardness and wear resistance of new martensitic shape memory (SM) nickel-titanium (NiTi) alloy...

  12. Vickers Hardness of Composite Resins Cured with LED and QTH Units

    Directory of Open Access Journals (Sweden)

    Alaghemand H

    2016-03-01

    Full Text Available Statement of Problem: One of the factors affecting the degree of polymerization of light-cured composites is the type of light-curing unit used. In addition, physicomechanical properties of the composite resins depend on the degree of conversion and polymerization. Objectives: Since the type of initiator in new composite resins is not explained by manufacturers, this study is an attempt to compare the depth of hardening, with two LED and QTH light-curing units. Materials and Methods: Fifteen samples prepared from Gradia Direct and Filtek Z250, both of which being universal, were cured with QTH (Astralis 7 and LED (Bluephase C8 light-curing units. All the samples were molded in polyester resin and cut from the middle by a disk. The hardness of the cut area was evaluated at 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5 and 4-mm depth intervals and also at the same interval as the width of the sample, with Vickers hardness machine, while the samples were placed in a darkroom. Data were statistically analyzed using one-way ANOVA, two-way ANOVA, t-test and post Hoc Tukey’s tests in SPSS, version 16. Results: Filtek Z250 was harder than Gradia Direct at all the depth with both light-curing units. The hardness of Filtek Z250 sample cured with Astralis 7 was higher than that cured with LED, but with Gradia Direct the LED unit resulted in higher hardness. Curing depth was not significantly different between the groups (p = 0.109. Conclusions: Vickers hardness number for both composites used in this study is in an acceptable range for clinical implications. The composites’ composition is important to be considered for selection of light unit. Based on the findings of the present study, LED did not present more curing depth compared with QTH.

  13. Mapping residual stress fields from Vickers hardness indents using Raman microprobe spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sparks, R.G.; Enloe, W.S.; Paesler, M.A.

    1988-12-01

    Micro-Raman spectroscopy is used to map the residual stress fields in the vicinity of Vickers hardness indents. Both 514.5 and 488.0 nm, light is used to excite the effect and the resulting shifted and broadened Raman peaks are analyzed using computer deconvolution. Half-wave plates are used to vary the orientation of the incident later light`s polarization state with respect to crystal orientation. The Raman scattered light is then analyzed for polarization dependences which are indicative of the various components of the Raman scattering tensor. Such studies can yield valuable information about the orientation of stress components in a well known stress field. The results can then be applied to the determination of stress components in machined semiconductor materials.

  14. Evaluation of Vickers hardness of different types of acrylic denture base resins with and without glass fibre reinforcement.

    Science.gov (United States)

    Farina, Ana Paula; Cecchin, Doglas; Soares, Rodrigo Gonçalves; Botelho, André Luís; Takahashi, Jessica Mie Ferreira Koyama; Mazzetto, Marcelo Oliveira; Mesquita, Marcelo Ferraz

    2012-06-01

    To evaluate the Vickers hardness of different acrylic resins for denture bases with and without the addition of glass fibres. It has been suggested that different polymerisation methods, as well as the addition of glass fibre (FV) might improve the hardness of acrylic. Five types of acrylic resin were tested: Vipi Wave (VW), microwave polymerisation; Vipi Flash (VF), auto-polymerisation; Lucitone (LT), QC20 (QC) and Vipi Cril (VC), conventional heat-polymerisation, all with or without glass fibre reinforcement (GFR) and distributed into 10 groups (n = 12). Specimens were then submitted to Vickers hardness testing with a 25-g load for 30 s. All data were submitted to anova and Tukey's HSD test. A significant statistical difference was observed with regard to the polymerisation method and the GFR (p hardness values, and VF and LT presented the lowest. In the presence of GFR, VC resin still presented the highest Vickers hardness values, and VF and QC presented the lowest. The acrylic resin VC and VW presented higher hardness values than VF and QC resins. Moreover, GFR increased the Vickers hardness of resins VW, VC and LT. © 2010 The Gerodontology Society and John Wiley & Sons A/S.

  15. Fabrication on Prototype of Depth Calibration Standard Machine for Elastomer Hardness Tester

    Science.gov (United States)

    Mongkolsuttirat, K.; Sanponpute, T.

    2017-09-01

    The prototype of depth calibration standard machine was fabricated to calibrate the depth of indentation for elastomer hardness tester. According to ISO 18898, ASTM D2240 and ASTM D1415, the measurement of indentation depth by a measuring device comprising a length-measuring system shall be in reference with the pressure foot of the elastomer hardness tester. Nation Institute of Metrology (Thailand); NIMT develop the depth calibration standard which can measure the indentation depth with always reference at the surface level of pressure foot of the hardness tester at each hardness scale. The calibration of the prototype of depth calibration standard machine was performed to provide the accuracy of the measurement of the machine which can be a suitable standard machine for depth of indentation within 1 μm complied with the requirement of ISO and ASTM standard. Furthermore, the prototype of depth calibration standard machine was validated to another NIMT method, which used the two length-measuring systems. The comparison results between 2 methods showed in a good agreement within 2 μm. Therefore, the NIMT prototype of depth calibration standard machine can be used as a depth calibration standard for elastomer hardness tester provided the required accuracy of measurement complied with ISO 18898, ASTM D2240 and ASTM D1415.

  16. Effect of a post-polymerization treatments on the flexural strength and Vickers hardness of reline and acrylic denture base resins

    Directory of Open Access Journals (Sweden)

    Rosangela Seiko Seo

    2007-12-01

    Full Text Available This study evaluated the effect of water-bath and microwave post-polymerization treatments on the flexural strength and Vickers hardness of four autopolymerizing reline resins (Duraliner II-D, Kooliner-K, Tokuso Rebase Fast-TR and Ufi Gel Hard C-UGH and one heat-polymerized acrylic resin (Lucitone 550-L, processed using two polymerization cycles (short cycle - 90 minutes at 73ºC and 100ºC for 30 minutes; and long cycle - 9 hours at 71ºC. For each material, thirty specimens (64 x 10 x 3.3 mm were made and divided into 3 groups (n=10. Specimens were tested after: processing (control group; water-bath at 55ºC for 10 minutes (reline materials or 60 minutes (L; and microwave irradiation. Flexural strength tests were performed at a crosshead speed of 5 mm/min using a three-point bending device with a span of 50 mm. The flexural strengths values were calculated in MPa. One fragment of each specimen was submitted to Vickers hardness test. Data were analyzed by 2-way ANOVA followed by Tukey's HSD test (alpha=0.05. L microwaved specimens (short cycle exhibited significantly higher flexural strength means than its respective control group (p<0.05. Water-bath promoted a significant increase (p<0.05 in flexural strength of K and L (long cycle. The hardness of the tested materials was not influenced by the post-polymerization treatments. Post-polymerization treatments could be used to improve the flexural strength of some materials tested.

  17. Strength analysis of a ferrite+bainite steel by AFM ultra-micro hardness tester; AFM chobisho katasa shiken ni yoru ferrite+bainite ko no kyodo kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Nagashima, N.; Miyahara, K.; Matsuoka, S.; Tsuzaki, K.; Hara, T.; Takahashi, T. [National Research Institute for Metals, Tsukuba (Japan)

    2000-12-01

    AFM ultra-micro hardness test, micro Vickers hardness test and TEM observation were conducted for a ferrite+bainite steel, which consists of bainite and polygonal ferrite. The results obtained are in the following. (1) AFM ultra-micro hardness tests show that nanoscopic hardness is 155 near the center of bainitic ferrite grain and increases closer to its boundary. Nanoscopic hardness is kept constant at 151 in the polygonal ferrite grain. (2) Micro-Vickers hardness tests show that macroscopic hardness is 251 and 147 for the bainite and polygonal ferrite regions, respectively. (3) TEM observations show that many carbides precipitated along the grain boundaries of bainitic ferrite and the dislocation density was almost same in both grains of bainitic and polygonal ferrite. It is suggested from the above results that the strengthening by grain boundaries is important in the bainitic ferrite and this strengthening effect is enhanced by carbides along grain boundaries. (author)

  18. Development of a New ATD-P Tester for Hard Wear Resistant Materials

    Directory of Open Access Journals (Sweden)

    Dojka M.

    2017-03-01

    Full Text Available The aim of presented studies was to develop a new geometry of the overflow part of standard ATD-C tester for derivative thermal analysis in a way that it would allow to obtain samples for abrasion and mechanical properties tests in the same mould without the need of cutting them from a block of material. The pattern of new ATD-P tester has parts reflecting implemented samples. Computer simulations regarding initial verification of new tester were performed in NovaFlow software. Chromium cast iron melts were made for testing the sampler in real conditions and TDA analysis for casting material were conducted. The sandmix was prepared on silica sand matrix per the ALPHASET technology. This new solution greatly simplifies the preparations of materials difficult to machine.

  19. Study on simple evaluation of mechanical properties of rock materials for Equotip hardness tester

    Science.gov (United States)

    Muramiya, Masaya; Yoshida, Hidenori; Tatsumi, Takakuni

    The mechanical properties of a rock or a soil are different in a narrow area. However, it is difficult to get their sample and to perform a various types of tests from the view points of time and economy. Thus, in this study, Equotip hardness test is focused. Because the test is easy to measure, it is possible to carry on the test at several points in a short time. Additionally, the cost performance of the test is excellent. In this article, the compression test for several artificial specimens is conducted, Equotip hardness test is also conducted before and after the compression test. Through the comparison between the measured data by the Equotip hardness test and the various properties, it turned out that the various properties can be presumed by Equotip hardness test.

  20. Effect of ion implantation on fatigue strength of martensitic stainless steel and surface hardness evaluation by ultra micro hardness tester

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Tsuneshichi [Ritsumeikan Univ., Kyoto (Japan). Faculty of Science and Engineering; Nakayama, Hideaki; Kato, Masahiko

    1995-02-01

    The effect of surface modification by ion implantation on the fatigue strength of 13Cr martensitic stainless steel was first described. Then the relationship between the fatigue performance and the surface microhardness of the material was dealt with. N{sup +} ions were implanted into the specimen surface with doses in the range of 5x10{sup 13} ions/cm{sup 2} - 5x10{sup 17} ions/cm{sup 2} with energy level of 350 keV. The results of out-of-plane bending fatigue tests revealed that the fatigue strength was improved by the ion implantation with implantation doses more than 2x10{sup 17} ions/cm{sup 2}, and that the further increase of fatigue strength was attained by the post heat treatment following the ion implantation. The microhardness of ultra-thin surface layer of submicron order was evaluated by the method previously proposed by the authors. The results indicated that the surface layer was hardened by the ion implantation and the hardness was increased by the post heat treatment. A remarkable increase in hardness was observed at the surface layer after the fatigue test, and this increase of the microhardness well coincides with the improvement of fatigue strength by ion implantation and post heat treatment. (author).

  1. Scratch Hardness and Wear Performance of Laser-Melted Steels : Effects of Anisotropy

    NARCIS (Netherlands)

    Beurs, H. de; Minholts, G.; Hosson, J.Th.M. De

    Effects of the orientation of dendrites on the scratch hardness and wear performance of laser-melted steels have been investigated. Scratch experiments have been carried out with a Vickers indenter and wear experiments with a pin-on-disk tester. The deformed structure is investigated, using

  2. Assessing spatial trends of cultural stone weathering intensity using a hardness tester: The case of Manglieu Saint-Sébastien church (France)

    Science.gov (United States)

    Roussel, Erwan; Gruson, Soizic; Vautier, Franck; Voldoire, Olivier; André, Marie-Françoise

    2014-05-01

    In heritage science, the quantitative assessment of rock hardness is of primary interest to characterize the degree of weathering of a cultural stone. Modern hardness testers are non-destructive and can be used on cultural heritage materials to collect repeated measurements of rock strength without causing damage. Furthermore, the development of portable solutions such as the Equotip Piccolo 2 facilitates the in situ hardness survey of a whole façade of a monument. It allows to address the question of spatial variability of weathering intensity within a monument, and the mapping of hardness values can reveal strong gradients or discontinuities in stone decay induced by restoration operations. The present study deals with the spatial distribution of stone hardness on the façade of the Saint-Sébastien Romanesque abbey church at Manglieu, in the French Massif Central. It was built during the twelfth century and listed as a protected historic monument in 1840. During the Late 19th century, the lower part of the west-facing wall was restored and the original gneissic material was replaced by granitic ashlars. Since this operation, an intense deterioration has affected the original gneissic stones overlying the granitic base of the wall. Our objective is to quantitatively assess the effect of this restoration on the current spatial trends of the gneiss hardness. Rock strength values were collected using the portable hardness tester Equotip Piccolo 2, and the spatial distribution was investigated at two scales: (i) At the portal scale, the hardness values of all stones were measured based on 30 values per stone; (ii) At the stone scale, a systematic sampling method was performed on two gneissic ashlars in order to collect hardness values over a grid of 9 cm resolution. On each sample, the repeated impact method was performed: 20 consecutive measurements at the same location were collected in order to reconstruct the spatial variation of weathering degree within the

  3. Evaluation of a new hardness tester (Cariotester): Comparison with transverse microradiography for assessing the inhibitory effect of fluoride application on bovine root dentin demineralization.

    Science.gov (United States)

    Sugawara, Toyotaro; Nakashima, Syozi; Shimizu, Akihiko; Tagami, Junji; Momoi, Yasuko

    2015-01-01

    The objective of this study was to investigate the correlation between CT depth, indentation depth determined by a new hardness tester (Cariotester), and the transverse microradiography (TMR) parameters, i.e., lesion depth and mineral loss. For that purpose, this study evaluated the feasibility of using Cariotester as a root caries diagnostic system and capability of Cariotester to detect effect of fluoride application on inhibiting dentin demineralization. Fluorides were applied to bovine root dentin specimens, which were subsequently demineralized for 1-21 days and then CT depth and TMR parameters were assessed. There were significant correlations between CT depth and TMR parameters in fluoride and non-fluoride groups. There were significant differences between fluoride and non-fluoride groups for CT depth and TMR parameters respectively. Current results suggested that Cariotester may be capable of providing an objective evaluation of root caries progression and the fluoride effect on inhibiting dentin demineralization.

  4. TUBE TESTER

    Science.gov (United States)

    Gittings, H.T. Jr.; Kalbach, J.F.

    1958-01-14

    This patent relates to tube testing, and in particular describes a tube tester for automatic testing of a number of vacuum tubes while in service and as frequently as may be desired. In it broadest aspects the tube tester compares a particular tube with a standard tube tarough a difference amplifier. An unbalanced condition in the circuit of the latter produced by excessive deviation of the tube in its characteristics from standard actuates a switch mechanism stopping the testing cycle and indicating the defective tube.

  5. Explosives tester

    Science.gov (United States)

    Haas, Jeffrey S [San Ramon, CA; Howard, Douglas E [Livermore, CA; Eckels, Joel D [Livermore, CA; Nunes, Peter J [Danville, CA

    2011-01-11

    An explosives tester that can be used anywhere as a screening tool by non-technical personnel to determine whether a surface contains explosives. First and second explosives detecting reagent holders and dispensers are provided. A heater is provided for receiving the first and second explosives detecting reagent holders and dispensers.

  6. The effect of CPP-ACP paste on the surface hardness of glass ionomer cement when immersed in orange juice

    Science.gov (United States)

    Nadia, A. A.; Eriwati, Y. K.; Damiyanti, M.

    2017-08-01

    This study aims to identify the effect of CPP-ACP paste on the surface hardness of glass ionomer cement (GIC) when immersed in orange juice. Eighteen specimens of Fuji IX GIC were divided into three groups: no CPP-ACP added (group A); CPP-ACP applied for three minutes (group B); and CPP-ACP applied for 30 minutes (group C). Specimens were immersed in orange juice and tested for surface hardness using a Vickers hardness tester. Data were analyzed using the one-way ANOVA (p = <0.05). Group A resulted in a 31.77 ± 0.77 Vickers Hardness Number (VHN), group B in a 42.97 ± 1.08 VHN, and group C in a 51.92 ± 0.27 VHN. It was concluded that application of CPP-ACP paste for 30 minutes is effective in preventing a decrease in the surface hardness of GIC due to orange juice consumption.

  7. Penetration Tester's Open Source Toolkit

    CERN Document Server

    Faircloth, Jeremy

    2011-01-01

    Great commercial penetration testing tools can be very expensive and sometimes hard to use or of questionable accuracy. This book helps solve both of these problems. The open source, no-cost penetration testing tools presented do a great job and can be modified by the user for each situation. Many tools, even ones that cost thousands of dollars, do not come with any type of instruction on how and in which situations the penetration tester can best use them. Penetration Tester's Open Source Toolkit, Third Edition, expands upon existing instructions so that a professional can get the most accura

  8. Cathodoluminescence study of vickers indentations in magnesium ...

    African Journals Online (AJOL)

    Vickers diamond pyramid indentations made in single crystal of magnesium oxide (MgO) were examined in an environmental scanning electron microscope interfaced with an AVS-2000 spectrophotometer for luminescence. Three distinct zones around the indentations were identified to exhibit cathodoluminescence, which ...

  9. Vickers Hardness Measurements of the M855 Cartridge Case Base

    Science.gov (United States)

    2009-04-01

    EMT B MACHAK PICATINNY ARSENAL NJ 07806-5000 5 COMMANDER US ARMY TACOM ARDEC AMSRD AAR AEP E D CARLUCCI K LAUGHLIN S...R COATES T EHLERS L MAGNESS B SCHUSTER AMSRD ARL WM TD T BJERKE T WEERASOORIYA AMSRD ARL WM TE B RINGERS 18 INTENTIONALLY LEFT BLANK.

  10. Investigation of micro-structure and micro-hardness properties of 304L stainless steel treated in a hot cathode arc discharge plasma

    Energy Technology Data Exchange (ETDEWEB)

    Malik, Hitendra K., E-mail: hkmalik@physics.iitd.ac.in [Department of Physics, Indian Institute of Technology Delhi, New Delhi – 110016 (India); Singh, Omveer [Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi – 110016 (India); Dahiya, Raj P. [Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi – 110016 (India); Deenbandhu Chhotu Ram University of Science and Technology, Murthal–131039 (India)

    2015-08-28

    We have established a hot cathode arc discharge plasma system, where different stainless steel samples can be treated by monitoring the plasma parameters and nitriding parameters independently. In the present work, a mixture of 70% N{sub 2} and 30% H{sub 2} gases was fed into the plasma chamber and the treatment time and substrate temperature were optimized for treating 304L Stainless Steel samples. Various physical techniques such as x-ray diffraction, energy dispersive x-ray spectroscopy and micro-vickers hardness tester were employed to determine the structural, surface composition and surface hardness of the treated samples.

  11. COPPERHEAD battery tester

    Science.gov (United States)

    Cruickshank, W. J.

    1983-06-01

    The development of a tester for the control section battery of the M712 Cannon-Launched Guided Projectile has fulfilled a requirement for the automatic testing of a series of batteries. The tester is a self-contained instrument that is used with a shock test system to rapidly perform complete tests after an initial setup.

  12. Effect of topical fluoride application on enamel after in-office bleaching, as evaluated using a novel hardness tester and a transverse microradiography method.

    Science.gov (United States)

    Fukuyama, Mai; Kawamoto, Chiharu; Saikaew, Pipop; Matsuda, Yasuhiro; Carvalho, Ricardo M; Selimovic, Denis; Sano, Hidehiko

    2017-12-01

    This study evaluated the effect of topical fluoride application on enamel hardness after in-office bleaching. Twelve human incisors were cut along the long axis, resulting in 24 halves used in four treatment groups (n = 6 in each group): (i) untreated group (C); (ii) in-office bleaching material (B); (iii) treatment with surface reaction-type prereacted glass-ionomer varnish after in-office bleaching (B+PRG); and (iv) treatment with acidulated phosphate fluoride solution after bleaching (B+F). All specimens were subjected to pH-cycling for 4 wk. Knoop hardness was measured using a Cariotester. The decalcification of enamel was assessed quantitatively by measuring the integrated mineral loss (ΔIML). Games-Howell analysis was used to assess statistical significance of between-group differences. The Knoop hardness decreased significantly after bleaching for all groups. In treatment groups B+PRG and B+F, the Knoop hardness returned to the original unbleached values after the first pH cycle and did not change afterwards. In treatment groups C and B there was a gradual decrease in the Knoop hardness until the fourth pH cycle. The integrated mineral loss, ΔIML, was significantly higher in treatment group B+F after 2 wk than in the other treatment groups. After 4 wk, the ΔIML in treatment group B was significantly higher than in treatment group B+PRG. The application of fluoride-containing materials after bleaching results in recuperation of hardness to levels similar to those of unbleached enamel. © 2017 Eur J Oral Sci.

  13. UW VLSI chip tester

    Science.gov (United States)

    McKenzie, Neil

    1989-12-01

    We present a design for a low-cost, functional VLSI chip tester. It is based on the Apple MacIntosh II personal computer. It tests chips that have up to 128 pins. All pin drivers of the tester are bidirectional; each pin is programmed independently as an input or an output. The tester can test both static and dynamic chips. Rudimentary speed testing is provided. Chips are tested by executing C programs written by the user. A software library is provided for program development. Tests run under both the Mac Operating System and A/UX. The design is implemented using Xilinx Logic Cell Arrays. Price/performance tradeoffs are discussed.

  14. Explosives tester with heater

    Science.gov (United States)

    Del Eckels, Joel [Livermore, CA; Nunes, Peter J [Danville, CA; Simpson, Randall L [Livermore, CA; Whipple, Richard E [Livermore, CA; Carter, J Chance [Livermore, CA; Reynolds, John G [San Ramon, CA

    2010-08-10

    An inspection tester system for testing for explosives. The tester includes a body and a swab unit adapted to be removeably connected to the body. At least one reagent holder and dispenser is operatively connected to the body. The reagent holder and dispenser contains an explosives detecting reagent and is positioned to deliver the explosives detecting reagent to the swab unit. A heater is operatively connected to the body and the swab unit is adapted to be operatively connected to the heater.

  15. Systematic hardness measurements on single crystals and ...

    Indian Academy of Sciences (India)

    Vickers and knoop hardness measurements were carried out on CsBr and CsI single crystals. Polycrystalline blanks of CsCl, CsBr and CsI were prepared by melting and characterized by X-ray diffraction. Vickers hardness measurements were carried out on these blanks. The hardness values were correlated with the lattice ...

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

    Science.gov (United States)

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

    2013-01-01

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

  17. Common tester platform concept.

    Energy Technology Data Exchange (ETDEWEB)

    Hurst, Michael James

    2008-05-01

    This report summarizes the results of a case study on the doctrine of a common tester platform, a concept of a standardized platform that can be applicable across the broad spectrum of testing requirements throughout the various stages of a weapons program, as well as across the various weapons programs. The common tester concept strives to define an affordable, next-generation design that will meet testing requirements with the flexibility to grow and expand; supporting the initial development stages of a weapons program through to the final production and surveillance stages. This report discusses a concept investing key leveraging technologies and operational concepts combined with prototype tester-development experiences and practical lessons learned gleaned from past weapons programs.

  18. Cable Tester Box

    Science.gov (United States)

    Lee, Jason H.

    2011-01-01

    Cables are very important electrical devices that carry power and signals across multiple instruments. Any fault in a cable can easily result in a catastrophic outcome. Therefore, verifying that all cables are built to spec is a very important part of Electrical Integration Procedures. Currently, there are two methods used in lab for verifying cable connectivity. (1) Using a Break-Out Box and an ohmmeter this method is time-consuming but effective for custom cables and (2) Commercial Automated Cable Tester Boxes this method is fast, but to test custom cables often requires pre-programmed configuration files, and cables used on spacecraft are often uniquely designed for specific purposes. The idea is to develop a semi-automatic continuity tester that reduces human effort in cable testing, speeds up the electrical integration process, and ensures system safety. The JPL-Cable Tester Box is developed to check every single possible electrical connection in a cable in parallel. This system indicates connectivity through LED (light emitting diode) circuits. Users can choose to test any pin/shell (test node) with a single push of a button, and any other nodes that are shorted to the test node, even if they are in the same connector, will light up with the test node. The JPL-Cable Tester Boxes offers the following advantages: 1. Easy to use: The architecture is simple enough that it only takes 5 minutes for anyone to learn how operate the Cable Tester Box. No pre-programming and calibration are required, since this box only checks continuity. 2. Fast: The cable tester box checks all the possible electrical connections in parallel at a push of a button. If a cable normally takes half an hour to test, using the Cable Tester Box will improve the speed to as little as 60 seconds to complete. 3. Versatile: Multiple cable tester boxes can be used together. As long as all the boxes share the same electrical potential, any number of connectors can be tested together.

  19. Four Sided Seal Tester

    Science.gov (United States)

    2009-07-01

    The Center for Advanced Food Technology School of Enviromental and Biological Sciences New Brunswick, NJ 08903 FTR 216 Defense Logistics Agency...specification for four sided seal tester as function of confinement plate distance” The following modifications were issued :  Jul 18, 2007 0013/01

  20. Transformer and Meter Tester

    Science.gov (United States)

    Stoms, R. M.

    1984-01-01

    Numerically-controlled 5-axis machine tool uses transformer and meter to determine and indicate whether tool is in home position, but lacks built-in test mode to check them. Tester makes possible test, and repair of components at machine rather then replace them when operation seems suspect.

  1. Inspection tester for explosives

    Science.gov (United States)

    Haas, Jeffrey S.; Simpson, Randall L.; Satcher, Joe H.

    2007-11-13

    An inspection tester that can be used anywhere as a primary screening tool by non-technical personnel to determine whether a surface contains explosives. It includes a body with a sample pad. First and second explosives detecting reagent holders and dispensers are operatively connected to the body and the sample pad. The first and second explosives detecting reagent holders and dispensers are positioned to deliver the explosives detecting reagents to the sample pad. A is heater operatively connected to the sample pad.

  2. Advanced TCA Backplane Tester

    CERN Document Server

    Oltean, Alexandra Dana

    2004-01-01

    At the beginning of 2003, the PICMG group adopted the AdvancedTCA (Advanced Telecom Computing Architecture) standard. The 10Gb/s backplane of the AdvancedTCA chassis is well specified in the standard but it remains however a high end product, which can be itself subject to printed circuit board manufacturing control problems that could greatly affect its quality control. In order to study the practical aspects of high speed Ethernet switching at 10Gb/s and to validate the signal integrity of the AdvancedTCA backplane, we developed a Backplane Tester. The tester system is able of running monitored PRBS traffic at 3.125Gb/s over every link on the AdvancedTCA backplane simultaneously and to monitor any possible connectivity failure immediately in terms of link and slot position inside the chassis. The present report presents the architectural hardware design, the control structure and software aspects of the AdvancedTCA Backplane Tester design.

  3. Single wheel testers, single track testers, and instrumented tractors

    Science.gov (United States)

    Single wheel testers and single track testers are used for determining tractive performance characteristics of tires and tracks. Instrumented tractors are useful in determining the tractive performance of tractors. These machines are also used for determining soil-tire and soil-track interactions,...

  4. Advanced TCA BAckplane Tester

    CERN Document Server

    Oltean, Alexandra Dana; PGNet2005

    2005-01-01

    The “Advanced Telecom Computing Architecture” (AdvancedTCA) is a modular standard chassis based system designed to support the needs of carrier class telecommunication applications. It is defined by a set of industry standards under the direction of the PICMG group. One early deployment of the standard technology has been a 10 Gigabit Ethernet switch developed in the framework of the EU funded ESTA project. In order to study the practical aspects of high speed Ethernet switching at 10 Gigabit and above and to validate the signal integrity of the AdvancedTCA backplane, we developed a Backplane Tester. This system is able to run pseudo-random bit sequence (PRBS) traffic at 3.125 Gbps over every link on the AdvancedTCA backplane simultaneously, and to monitor any possible connectivity failure immediately in terms of the link and slot positions inside the chassis. In this paper, we describe the design and the practical architectural hardware and software aspects of the AdvancedTCA Backplane Tester. We also pr...

  5. Determination of Vickers microhardness on porous silicon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Masis, M. [Department of Physics, Wright State University, Dayton OH 45435 (United States); Ramirez-Porras, A. [Centro de Investigacion en Ciencia e Ingenieria de Materiales (CICIMA) and Escuela de Fisica, Universidad de Costa Rica, San Pedro de Montes de Oca 2060 (Costa Rica)], E-mail: aramirez@fisica.ucr.ac.cr

    2008-02-29

    The Vickers microhardness values of two different sets of porous silicon layers were determined at applied load of 98 mN. The sets consisted of Boron-doped substrates anodized at diverse current densities for two different amounts of hydrofluoric acid (HF) in the etching solution. We found that the microhardness of the samples with lower content of HF at the anodization process showed higher values, whereas the Vickers parameter diminishes consistently for higher current densities. A possible explanation of this behavior is proposed.

  6. Comparative effect of different polymerization techniques on residual monomer and hardness properties of PMMA-based denture resins.

    Science.gov (United States)

    Ayaz, Elif Aydogan; Durkan, Rukiye; Koroglu, Ayşegul; Bagis, Bora

    2014-12-30

    The aim of this study was to compare the residual monomer and microhardness of poly(methyl methacrylate) (PMMA)-based denture resins processed by using autoclave and conventional water bath techniques. To determine the amount of residual methyl methacrylate (MMA) monomer, disk-shaped specimens (n=5) were prepared from 3 different acrylic resins (Meliodent, Paladent and Qc-20). Control groups were polymerized in water bath for 30 minutes at 100°C. The study groups were prepared in an autoclave device for 60°C/30 min followed 130°C/10 min and the other group for 60°C/30 min followed by 130°C/20 min. According to standard calibration curves, ultraviolet spectrophotometry at 230 nm was used to determine the residual monomer. For the Vickers hardness measurements, disk-shaped specimens (n=5) were prepared for each test group. Hardness measurements were performed with a Vickers hardness tester under a 4.91-N press load for a 30 seconds, after immersion in distilled water at 37ºC for 48 hours. The data were analyzed by ANOVA and Tukey HSD test (phardness for all resin groups (p0.05). The autoclave polymerization technique exhibited significantly lower residual monomer content and greater hardness than conventional heat polymerization.

  7. In Vitro Comparative Study of Two Different Bleaching Agents on Micro-hardness Dental Enamel.

    Science.gov (United States)

    Fatima, Nazish; Ali Abidi, Syed Yawar; Meo, Ashraf Ali

    2016-02-01

    To evaluate the effect of home-use bleaching agent containing 16% Carbamide Peroxide (CP) and in-office bleaching agent containing 38% Hydrogen Peroxide (HP) on enamel micro-hardness. An in vitroexperimental study. Department of Operative Dentistry and Science of Dental Materials at Dr. Ishrat-ul-Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences and Material Engineering Department of NED University of Engineering and Technology, Karachi, from July to December 2014. Atotal of 90 enamel slabs from 45 sound human 3rd molar were randomly divided into 3 groups. Each group contained 30 specimens (n=30). Group 1 was kept in artificial saliva at 37°C in incubator during the whole experiment. However, Groups 2 and 3 were treated with power whitening gel and tooth whitening pen respectively. After bleaching session, specimens were thoroughly rinsed with deionized water again for 10 seconds and then stored in artificial saliva at 37°C in incubator. Artificial saliva was changed after every 2 days. The Vickers hardness tester (Wolpert 402 MVD, Germany) was adjusted to a load of 0.1 kg (100 gm) and dwell time of 5 seconds. Three Vickers were performed on each specimen using a hardness tester according to the ISO 6507-3:1998 specification. Micro-hardness measurements were performed before and after bleaching at day 1, 7 and 14. In the control group, the baseline micro-hardness was 181.1 ±9.3 which was reduced after the storage on day 1, 7 and 14 (p = 0.104). In Group 2, baseline micro-hardness was 180.4 ±10.1 which was reduced to 179.79 ±10.0 units after day 1. Whereas, on day 7 and 14, the values of micro-hardness were 179.8 ±10 and 179.7 ±10.29, respectively (p=0.091). Furthermore, the baseline micro-hardness in Group 3 was 174.0 ±22.9 units which was reduced to 173 ±23 on day 1, 170 ±30 on day 7 and 173 ±23 on day 14 (p = 0.256). The statistically insignificant difference was found among micro-hardness values of different bleaching

  8. Evaluation of Polymerization Efficacy in Composite Resins via FT-IR Spectroscopy and Vickers Microhardness Test.

    Science.gov (United States)

    Jafarzadeh, Tahereh-Sadat; Erfan, Mohammad; Behroozibakhsh, Marjan; Fatemi, Mostafa; Masaeli, Reza; Rezaei, Yashar; Bagheri, Hossein; Erfan, Yasaman

    2015-01-01

    Background and aims. Polymerization efficacy affects the properties and performance of composite resin restorations.The purpose of this study was to evaluate the effectiveness of polymerization of two micro-hybrid, two nano-hybrid and one nano-filled ormocer-based composite resins, cured by two different light-curing systems, using Fourier transformation infrared (FT-IR) spectroscopy and Vickers microhardness testing at two different depths (top surface, 2 mm). Materials and methods. For FT-IR spectrometry, five cylindrical specimens (5mm in diameter × 2 mm in length) were prepared from each composite resin using Teflon molds and polymerized for 20 seconds. Then, 70-μm wafers were sectioned at the top surface and at2mm from the top surface. The degree of conversion for each sample was calculated using FT-IR spectroscopy. For Vickers micro-hardness testing, three cylindrical specimens were prepared from each composite resin and polymerized for 20 seconds. The Vickers microhardness test (Shimadzu, Type M, Japan) was performed at the top and bottom (depth=2 mm) surfaces of each specimen. Three-way ANOVA with independent variables and Tukey tests were performed at 95% significance level. Results. No significant differences were detected in degree of conversion and microhardness between LED and QTH light-curing units except for the ormocer-based specimen, CeramX, which exhibited significantly higher DC by LED. All the composite resins showed a significantly higher degree of conversion at the surface. Microhardness was not significantly affected by depth, except for Herculite XRV Ultra and CeramX, which showed higher values at the surface. Conclusion. Composite resins containing nano-particles generally exhibited more variations in degree of conversion and microhardness.

  9. Evaluation of Polymerization Efficacy in Composite Resins via FT-IR Spectroscopy and Vickers Microhardness Test

    Science.gov (United States)

    Jafarzadeh, Tahereh-Sadat; Erfan, Mohammad; Behroozibakhsh, Marjan; Fatemi, Mostafa; Masaeli, Reza; Rezaei, Yashar; Bagheri, Hossein; Erfan, Yasaman

    2015-01-01

    Background and aims. Polymerization efficacy affects the properties and performance of composite resin restorations.The purpose of this study was to evaluate the effectiveness of polymerization of two micro-hybrid, two nano-hybrid and one nano-filled ormocer-based composite resins, cured by two different light-curing systems, using Fourier transformation infrared (FT-IR) spectroscopy and Vickers microhardness testing at two different depths (top surface, 2 mm). Materials and methods. For FT-IR spectrometry, five cylindrical specimens (5mm in diameter × 2 mm in length) were prepared from each composite resin using Teflon molds and polymerized for 20 seconds. Then, 70-μm wafers were sectioned at the top surface and at2mm from the top surface. The degree of conversion for each sample was calculated using FT-IR spectroscopy. For Vickers micro-hardness testing, three cylindrical specimens were prepared from each composite resin and polymerized for 20 seconds. The Vickers microhardness test (Shimadzu, Type M, Japan) was performed at the top and bottom (depth=2 mm) surfaces of each specimen. Three-way ANOVA with independent variables and Tukey tests were performed at 95% significance level. Results. No significant differences were detected in degree of conversion and microhardness between LED and QTH light-curing units except for the ormocer-based specimen, CeramX, which exhibited significantly higher DC by LED. All the composite resins showed a significantly higher degree of conversion at the surface. Microhardness was not significantly affected by depth, except for Herculite XRV Ultra and CeramX, which showed higher values at the surface. Conclusion. Composite resins containing nano-particles generally exhibited more variations in degree of conversion and microhardness. PMID:26889359

  10. Evaluation of Polymerization Efficacy in Composite Resins via FT-IR Spectroscopy and Vickers Microhardness Test

    Directory of Open Access Journals (Sweden)

    Tahereh-Sadat Jafarzadeh

    2015-12-01

    Full Text Available Background and aims. Polymerization efficacy affects the properties and performance of composite resin restorations.The purpose of this study was to evaluate the effectiveness of polymerization of two micro-hybrid, two nano-hybrid and one nano-filled ormocer-based composite resins, cured by two different light-curing systems, using Fourier transformation infrared (FT-IR spectroscopy and Vickers microhardness testing at two different depths (top surface, 2 mm. Materials and methods. For FT-IR spectrometry, five cylindrical specimens (5mm in diameter × 2 mm in length were prepared from each composite resin using Teflon molds and polymerized for 20 seconds. Then, 70-μm wafers were sectioned at the top surface and at2mm from the top surface. The degree of conversion for each sample was calculated using FT-IR spectroscopy. For Vickers micro-hardness testing, three cylindrical specimens were prepared from each composite resin and polymerized for 20 seconds. The Vickers microhardness test (Shimadzu, Type M, Japan was performed at the top and bottom (depth=2 mm surfaces of each specimen. Three-way ANOVA with independent variables and Tukey tests were performed at 95% significance level. Results. No significant differences were detected in degree of conversion and microhardness between LED and QTH light-curing units except for the ormocer-based specimen, CeramX, which exhibited significantly higher DC by LED. All the composite resins showed a significantly higher degree of conversion at the surface. Microhardness was not significantly affected by depth, except for Herculite XRV Ultra and CeramX, which showed higher values at the surface. Conclusion. Composite resins containing nano-particles generally exhibited more variations in degree of conversion and microhardness.

  11. Spring performance tester for miniature extension springs

    Science.gov (United States)

    Salzbrenner, Bradley; Boyce, Brad

    2017-05-16

    A spring performance tester and method of testing a spring are disclosed that has improved accuracy and precision over prior art spring testers. The tester can perform static and cyclic testing. The spring tester can provide validation for product acceptance as well as test for cyclic degradation of springs, such as the change in the spring rate and fatigue failure.

  12. The effects of a K2SO4 solution on the surface hardness of gypsum type III

    Science.gov (United States)

    Permana, B. N.; Triaminingsih, S.; Indrani, D. J.

    2017-08-01

    Gypsum type III is commonly used for working models and as a tool for restorations or dentures manufacturing in the laboratory. K2SO4 solution is recommended to be added to gypsum type III because it can accelerate the setting time. The aim of this study was to identify the effects of a K2SO4 solution on the surface hardness of gypsum type III. The surface hardness was tested using a Vickers Hardness Tester with a load of 500 gf. The results were analyzed using a one-way ANOVA. The surface hardness of gypsum type III manipulated using a 1.5% K2SO4 solution was higher than the surface hardness of gypsum type III manipulated without K2SO4 but lower than the surface hardness of gypsum type IV. Therefore, the use of a 1.5% K2SO4 solution can increase the hardness of gypsum type III but not enough to make it equivalent to the surface hardness of gypsum type IV.

  13. Non-Intrusive Cable Tester

    Science.gov (United States)

    Medelius, Pedro J. (Inventor); Simpson, Howard J. (Inventor)

    1999-01-01

    A cable tester is described for low frequency testing of a cable for faults. The tester allows for testing a cable beyond a point where a signal conditioner is installed, minimizing the number of connections which have to be disconnected. A magnetic pickup coil is described for detecting a test signal injected into the cable. A narrow bandpass filter is described for increasing detection of the test signal. The bandpass filter reduces noise so that a high gain amplifier provided for detecting a test signal is not completely saturate by noise. To further increase the accuracy of the cable tester, processing gain is achieved by comparing the signal from the amplifier with at least one reference signal emulating the low frequency input signal injected into the cable. Different processing techniques are described evaluating a detected signal.

  14. Multimodal Friction Ignition Tester

    Science.gov (United States)

    Davis, Eddie; Howard, Bill; Herald, Stephen

    2009-01-01

    The multimodal friction ignition tester (MFIT) is a testbed for experiments on the thermal and mechanical effects of friction on material specimens in pressurized, oxygen-rich atmospheres. In simplest terms, a test involves recording sensory data while rubbing two specimens against each other at a controlled normal force, with either a random stroke or a sinusoidal stroke having controlled amplitude and frequency. The term multimodal in the full name of the apparatus refers to a capability for imposing any combination of widely ranging values of the atmospheric pressure, atmospheric oxygen content, stroke length, stroke frequency, and normal force. The MFIT was designed especially for studying the tendency toward heating and combustion of nonmetallic composite materials and the fretting of metals subjected to dynamic (vibrational) friction forces in the presence of liquid oxygen or pressurized gaseous oxygen test conditions approximating conditions expected to be encountered in proposed composite material oxygen tanks aboard aircraft and spacecraft in flight. The MFIT includes a stainless-steel pressure vessel capable of retaining the required test atmosphere. Mounted atop the vessel is a pneumatic cylinder containing a piston for exerting the specified normal force between the two specimens. Through a shaft seal, the piston shaft extends downward into the vessel. One of the specimens is mounted on a block, denoted the pressure block, at the lower end of the piston shaft. This specimen is pressed down against the other specimen, which is mounted in a recess in another block, denoted the slip block, that can be moved horizontally but not vertically. The slip block is driven in reciprocating horizontal motion by an electrodynamic vibration exciter outside the pressure vessel. The armature of the electrodynamic exciter is connected to the slip block via a horizontal shaft that extends into the pressure vessel via a second shaft seal. The reciprocating horizontal

  15. Hydrogen fracture toughness tester completion

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, Michael J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-09-30

    The Hydrogen Fracture Toughness Tester (HFTT) is a mechanical testing machine designed for conducting fracture mechanics tests on materials in high-pressure hydrogen gas. The tester is needed for evaluating the effects of hydrogen on the cracking properties of tritium reservoir materials. It consists of an Instron Model 8862 Electromechanical Test Frame; an Autoclave Engineering Pressure Vessel, an Electric Potential Drop Crack Length Measurement System, associated computer control and data acquisition systems, and a high-pressure hydrogen gas manifold and handling system.

  16. The variation in surface morphology and hardness of human deciduous teeth samples after laser irradiation

    Science.gov (United States)

    Khalid, Arooj; Bashir, Shazia; Akram, Mahreen; Salman Ahmed, Qazi

    2017-11-01

    The variation in surface morphology and hardness of human deciduous teeth samples has been investigated after laser irradiation at different wavelengths and energies. Nd:YAG was employed as a source of irradiation for IR (1064 nm) and visible (532 nm) radiation, whereas an excimer laser was used as the source of UV (248 nm) radiation. Scanning electron microscope (SEM) analysis was carried out to reveal the surface morphological evolution of teeth samples. Vickers microhardness tester was employed to investigate the modifications in the hardness of the laser-treated samples. It is observed from SEM analysis that IR wavelength is responsible for ablation of collagen matrix and intertubular dentine. For visible radiation, the ablation of collagen along with hydroxypatite is observed. With UV radiation, the ablation of peritubular dentine is dominant and is responsible for the sealing of tubules. The decrease in hardness at lower energy for both wavelengths is due to the evaporation of carbon content. With increasing energy, evaporation of water along with carbon content, and resolidification and re-organization of inorganic content causes the increase in hardness of the treated dentine. SEM as well as microhardness analyses reveal that laser wavelengths and energy of laser radiation significantly influence the surface morphology and hardness of samples.

  17. Hardness of CaF2 and BaF2 solid lubricants at 25 to 670 deg C

    Science.gov (United States)

    Deadmore, Daniel L.; Sliney, Harold E.

    1987-01-01

    Plastic deformation is a prominent factor in determining the lubricating value of solid lubricants. Little information is available and its direct measurement is difficult so hardness, which is an indirect measure of this property was determined for fluoride solid lubricant compositions. The Vickers hardness of BaF2 and CaF2 single crystals was measured up to 670 C in a vacuum. The orientation of the BaF2 was near the (013) plane and the CaF2 was about 16 degrees from the degrees from the (1'11) plane. The BaF2 has a hardness of 83 kg/sq mm at the 25 C and 9 at the 600 C. The CaF2 is 170 at 25 C and 13 at 670 C. The decrease in hardness in the temperature range of 25 to 100 C is very rapid and amounts to 40% for both materials. Melts of BaF2 and CaF2 were made in a platinum crucible in ambient air with compositions of 50 to 100 wt% BaF2. The Vickers hardness of these polycrystalline binary compositions at 25 C increased with increasing CaF2 reaching a maximum of 150 kn/sq mm near the eutectic. The polycrystalline CaF2 was 14% softer than that of the single crystal surface and BsF2 was 30% harder than the single crystal surface. It is estimated that the brittle to ductile transition temperature for CaF2 and BaF2 is less than 100 C for the conditions present in the hardness tester.

  18. Rapport Pitfalls of Beginning Testers.

    Science.gov (United States)

    Teglasi, Hedwig; Freeman, Robert W.

    1983-01-01

    Uses verbatim examples from observation notes to describe common pitfalls of beginning testers in the area of rapport with children. Concluded that trainees in testing often cannot translate guidelines in the literature into effective rapport in the testing session. Observation of test administration in a realistic setting is essential. (JAC)

  19. Systematic hardness studies on lithium niobate crystals

    Indian Academy of Sciences (India)

    Unknown

    1975) made Knoop hardness ... mentioned that Knoop and Vickers hardness values generally agree to within 5% (Mott 1956). Brown et al ... In the present communication, we report a detailed study of the load-dependence of hardness on two ...

  20. Finger wear detection for production line battery tester

    Science.gov (United States)

    Depiante, Eduardo V.

    1997-01-01

    A method for detecting wear in a battery tester probe. The method includes providing a battery tester unit having at least one tester finger, generating a tester signal using the tester fingers and battery tester unit with the signal characteristic of the electrochemical condition of the battery and the tester finger, applying wavelet transformation to the tester signal including computing a mother wavelet to produce finger wear indicator signals, analyzing the signals to create a finger wear index, comparing the wear index for the tester finger with the index for a new tester finger and generating a tester finger signal change signal to indicate achieving a threshold wear change.

  1. 21 CFR 872.1720 - Pulp tester.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pulp tester. 872.1720 Section 872.1720 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.1720 Pulp tester. (a) Identification. A pulp tester is an AC or...

  2. 24 CFR 125.107 - Testers.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Testers. 125.107 Section 125.107... INITIATIVES PROGRAM § 125.107 Testers. The following requirements apply to testing activities funded under the FHIP: (a) Testers must not have prior felony convictions or convictions of crimes involving fraud or...

  3. 21 CFR 870.5325 - Defibrillator tester.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Defibrillator tester. 870.5325 Section 870.5325...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Therapeutic Devices § 870.5325 Defibrillator tester. (a) Identification. A defibrillator tester is a device that is connected to the output of a...

  4. Hard superconducting nitrides

    Science.gov (United States)

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

    2005-01-01

    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 δ-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

  5. Effects of sour curry temperature with fermented shrimp paste on surface hardness of tooth enamel

    Directory of Open Access Journals (Sweden)

    Pojjanut Benjakul

    2011-08-01

    Full Text Available The aim of this study was to evaluate the effect of temperature of Thai sour curry with and without fermented shrimppaste (Kapi on enamel hardness. The pH and the titratable acidity of the assigned food were determined for Kangsom withKapi and Kangsom without Kapi at 25C, 37C and 55C. Thirty six enamel specimens were randomly assigned into 6 groups.Each group was exposed to the assigned foods at 25C, 37C and 55C at 15 min interval for 3 periods and the last intervalsat 60 min. The enamel surface hardness was evaluated by a Vickers microhardness tester. Increasing the temperature of thefood resulted in a decreasing pH and a slightly increased titratable acidity content. The hardness values of enamel exposurefor Kangsom with Kapi and Kangsom without Kapi were significantly different for all temperatures. The hardness value ofenamel exposure for Kangsom with Kapi at 55C was higher than that for exposure at 25C and 37C. In contrast, the hardnessvalue of enamel exposure for Kangsom without Kapi at 55oC was significant lower than that for exposure at 25C and37C. The temperature of Kangsom had an effect on enamel softening and Kangsom without Kapi had higher erosive potentialthan Kangsom with Kapi.

  6. Instrumented Pneumatic-Impact Tester

    Science.gov (United States)

    Shelley, Richard M.; Armendariz, Norman

    1993-01-01

    Pneumatic-impact tester is small pressure chamber equipped with specimen holder and optical port. Device designed to test susceptibility of polymeric material to ignition by "pneumatic impact" in high-pressure gaseous oxygen. Used to determine differences among susceptibilities to ignition of different materials and of different batches of nominally same material proposed for use in systems containing pressurized oxygen. Also used to show characteristics of ignition and combustion.

  7. Effects of thermal cycling on surface roughness, hardness and flexural strength of polymethylmethacrylate and polyamide denture base resins.

    Science.gov (United States)

    Ayaz, Elif Aydoğan; Bağış, Bora; Turgut, Sedanur

    2015-10-16

    The purpose of this study was to evaluate the effects of thermal cycling on the surface roughness, hardness and flexural strength of denture resins. Polyamide (PA; Deflex and Valplast) and polymethylmethacrylate (PMMA; QC-20 and Acron MC) denture materials were selected. A total of 180 specimens were fabricated and then divided into 3 groups. The first group (group 1) acted as a control and was not thermocycled. The second group (group 2) was subjected to thermocycling for 10,000 cycles in artificial saliva and 5,000 cycles in distilled water. The last group (group 3) was thermocycled for 20,000 cycles in artificial saliva and 10,000 cycles in distilled water. The surface roughness were measured with a profilometer. The hardness of the resins were measured with a Vickers Hardness Tester using a 100-gf load. The flexural strength test was performed using the universal test machine with a crosshead speed of 5 mm/min. Data were analyzed using statistical software. The results of the measurements in the 3 different tests were analyzed by Kruskal-Wallis test with Bonferroni correction. Multiple comparisons were made by Conover and Wilcoxon tests. There was a significant difference between the PMMA and PA groups in terms of surface roughness, hardness and transverse strength before and after thermal cycling (p<0.001). Thermal cycling did not change the surface roughness, hardness and flexural strength values of either the PMMA or PA group (p>0.001).

  8. Enhanced Master Controller Unit Tester

    Science.gov (United States)

    Benson, Patricia; Johnson, Yvette; Johnson, Brian; Williams, Philip; Burton, Geoffrey; McCoy, Anthony

    2007-01-01

    The Enhanced Master Controller Unit Tester (EMUT) software is a tool for development and testing of software for a master controller (MC) flight computer. The primary function of the EMUT software is to simulate interfaces between the MC computer and external analog and digital circuitry (including other computers) in a rack of equipment to be used in scientific experiments. The simulations span the range of nominal, off-nominal, and erroneous operational conditions, enabling the testing of MC software before all the equipment becomes available.

  9. Development of the tyre tester

    CSIR Research Space (South Africa)

    Kuduntwane, P

    2012-10-01

    Full Text Available and analysing a vehicle?s performance. Therefore, accurate and effi cient tyre models for off-road vehicles are needed. But to get that, we need a tyre tester for adjustable slip, camber and caster angles for improved tyre lateral data. OBJECTIVE..., it should be modified to have the necessary wheel orientation, especially for proper vehicle handling, and then to improve the lateral test data. We also need to measure the effect of camber on lateral forces, as well as the effect of caster on lateral...

  10. Influence of polymerization time and depth of cure of resin composites determined by Vickers hardness

    Directory of Open Access Journals (Sweden)

    Marco Lombardini

    2012-01-01

    Conclusion: Among the materials tested, the nanofilled and the nanohybrid resin composites were rather insensible to thickness variations. Miicrohybrid composites, instead, had features different from one another.

  11. The characterization of Vicker`s microhardness indentations and pile-up profiles as a strain-hardening microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Santos, C. Jr. [Nuclear Regulatory Commission, Washington, DC (United States). Div. of Engineering Technology; Odette, G.R.; Lucas, G.E.; Schroeter, B.; Klinginsmith, D. [California Univ., Santa Barbara, CA (United States). Dept. of Mechanical Engineering; Yamamoto, T. [Tohoku Univ., Sendai (Japan)

    1998-04-01

    Microhardness measurements have long been used to examine strength properties and changes in strength properties in metals, for example, as induced by irradiation. Microhardness affords a relatively simple test that can be applied to very small volumes of material. Microhardness is nominally related to the flow stress of the material at a fixed level of plastic strain. Further, the geometry of the pile-up of material around the indentation is related to the strain-hardening behavior of a material; steeper pile-ups correspond to smaller strain-hardening rates. In this study the relationship between pile-up profiles and strain hardening is examined using both experimental and analytical methods. Vickers microhardness tests have been performed on a variety of metal alloys including low alloy, high Cr and austenitic stainless steels. The pile-up topology around the indentations has been quantified using confocal microscopy techniques. In addition, the indentation and pile-up geometry has been simulated using finite element method techniques. These results have been used to develop an improved quantification of the relationship between the pile-up geometry and the strain-hardening constitutive behavior of the test material.

  12. The ATLAS RunTimeTester

    CERN Document Server

    The ATLAS collaboration

    2016-01-01

    The ATLAS RunTimeTester is a job based software test system. The RunTimeTester runs jobs, and optional tests on the job outputs. Job and test results are reported via a web site. The system currently runs $\\approx$ 8000 jobs daily, and the web site receives $\\approx$ 25K hits a week. This note provides an overview of the system.

  13. Tester-assisted built in test

    Science.gov (United States)

    Guntheroth, Kurt

    It is noted that board makers invest considerable time and money writing extensive self-tests and that this investment can be multiplied by selecting ATE (automatic test equipment) that complements and extends the power of the self-test. The tester can diagnose boards in situations where a fault prevents the self-test from running. If the tester monitors such resources as processor, memory, and I/O, confidence in test results is improved. The tester can be used during development of the self-test and to turn on prototypes before the self-test is complete. The author argues that emulative functional testers outperform other types of ATE on boards with BIST (built-in self-test) and lists features of emulative functional testers that are most important to users of BIST.

  14. The effects of Exposure Times and Light Curing Sources on Surface Micro-Hardness of a Resin Modified Glass Ionomer

    Directory of Open Access Journals (Sweden)

    Iman Parisay

    2014-06-01

    Full Text Available Introduction: The aim of this study was to evaluate the influenceof different light curing systems and curing times on the micro-hardness of aresin modified glass ionomer. Methods: Forty two samples of ResinModified Glass Ionomer (RMGI were prepared using stainless steel cylindrical mold(8 × 2 mm and randomly divided into six groups of seven. Three groups werecured with a Quartz Tungsten Halogen (QTH light cure unit and the other threegroups were polymerized with LED unit for 20, 30 and 40 seconds. All sampleswere stored in distilled water for 24 hours. The micro-hardness was measured onthe top and bottom surfaces of the samples by Vickers hardness tester. Datawere analyzed by two–way ANOVA and Tukey’s post-hoc tests. Results: Two-wayANOVA showed that QTH light-cure unit had higher percentage in depth of curethan LED light-curing unit in both surfaces; whereas, the application time hasno significant effect on it. There was no interaction between two variables. Inboth light-curing groups, the values of top and bottom surfaces micro-hardnesswere increased as the application time increased, but there was not anystatistically significant difference among these groups except for 40-second groupof LED light-curing unit which was significantly higher than 20-second and30-second groups (P

  15. Fabrication and characterization of Ti-Nb-HA alloy by mechanical alloying and spark plasma sintering for hard tissue replacements

    Science.gov (United States)

    Singh, Ramandeep; Pal Singh, Bhupinder; Gupta, Anjali; Prakash, Chander

    2017-08-01

    In the present research work, a β-type Ti-35Nb-10HA alloy was successfully fabricated by mechanical alloying of titanium (Ti), niobium (Nb), and hydroxyaptite (HA) powders followed by consolidation using Spark Plasma Sintering technique. The effect of HA on the microstructure and mechanical properties were studied. The microstructure, surface topography, and element composition of the Ti-Nb-HA alloy was investigated using optical microscope, field-emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The micro-hardness of the specimens was measured on a Vickers hardness tester. The microstructure examination of the compact revealed that the alloy distinctly shows the primary grain boundaries along with secondary grain boundary. It was observed that complex reactions between HA and alloy elements occurred during the sintering process of Ti-35Nb-10HA alloy and biocompatible phases [Ca3(PO4)2, CaTiO3, Nb8P5, CaO, TiP, Nb4O5, and TiO2] were generated in the compact, which is beneficial to form apatite and improved the bioactivity of the alloy for osseiointegartion. The fabricated Ti-35Nb-15HA alloy exhibits maximum micro-hardness (∼786 HV), which is very high value as compared to the alloys reported in literature. Based on these above observations, it is expected that the as-fabricated Ti-35Nb-10HA alloy is suggested for dental and orthopaedic applications.

  16. FPGA-based Bit-Error-Rate Tester for SEU-hardened Optical Links

    CERN Document Server

    Detraz, S; Moreira, P; Papadopoulos, S; Papakonstantinou, I; Seif El Nasr, S; Sigaud, C; Soos, C; Stejskal, P; Troska, J; Versmissen, H

    2009-01-01

    The next generation of optical links for future High-Energy Physics experiments will require components qualified for use in radiation-hard environments. To cope with radiation induced single-event upsets, the physical layer protocol will include Forward Error Correction (FEC). Bit-Error-Rate (BER) testing is a widely used method to characterize digital transmission systems. In order to measure the BER with and without the proposed FEC, simultaneously on several devices, a multi-channel BER tester has been developed. This paper describes the architecture of the tester, its implementation in a Xilinx Virtex-5 FPGA device and discusses the experimental results.

  17. Tester akumulátorů

    OpenAIRE

    Pisca, Marek

    2014-01-01

    Predložená diplomová práca sa zaoberá teóriou Li-ion akumulátorov a ich nabíjaním. V práci bol navrhnutý tester akumulátorov pre automatické nabíjanie a vybíjanie Li-ion akumulátorov. Tento tester je riadený pomocou mikroprocesora. This master´s thesis is dealing with the theory of Li-ion accumulators and theirs charching. In this thesis has been designed accumulator tester for automatic charging and discharging of Li-ion accumulator. This tester is controlled by microprocessor. E...

  18. Rolling and Annealing Effects on Microstructure and Hardness of Commercial 405 Stainless Steel

    Directory of Open Access Journals (Sweden)

    A.K. Jahja

    2007-07-01

    Full Text Available The "cold-rolling" experiments for several values of true strain namely 5 percent, 10 percent, and 15 percent respectively have been carried out on commercial SS-405 steel samples at 350oC; the as-rolled samples were cut into several pieces in size of 10 x 10 x 5 mm3, and some pieces were annealed to 550oC for 24 hours. All samples were then mounted and polished before etching in order to observe the grain boundaries. The microstructure observation on all samples was carried out by using optical microscope (MO, meanwhile X-ray diffraction technique was employed in order to support the identification of the existing phases and to verify changes with respect to crystal orientation; the hardness tests were carried out by using Vickers micro hardness tester. The microstructure observation supported by X-ray diffraction results shows that the phase grains of rolled sample tends to take the oblong-shape, accompanied by a preferred orientation predominantly inclined toward the (110 plane. The microhardness testing results show that there has been an increase in the hardness of the as-rolled samples; Mainly because of the nearly negligible thickness of the original sample (being only 5 mm in size, the 15 percent as-rolled samples exhibits only a slight reduction in hardness compared to the 10 percent as-rolled samples; The main cause of this effect is the movement of some dislocations infiltrating the surface resulting in the reduction of the inner-stress in the bulk of the samples. In the rolled-annealed samples there is a very significant reduction in hardness compared to the as-rolled samples. Here the main cause is the recrystallization process taking place during annealing, which tends to significantly reduce the dislocations.

  19. A comparison of damage profiling of automated tap testers on aircraft CFRP panel

    Science.gov (United States)

    Mohd Aris, K. D.; Shariff, M. F.; Abd Latif, B. R.; Mohd Haris, M. Y.; Baidzawi, I. J.

    2017-12-01

    The use of composite materials nevertheless is getting more prominent. The combination of reinforcing fibers and matrices will produce the desired strength orientation, tailorability and not to mention the complex shape that is hard to form on metallic structure. The weight percentage of composite materials used in aerospace, civil, marine etc. has increased tremendously. Since composite are stacked together, the possibility of delamination and/disbond defects are highly present either in the monolithic or sandwich structures. Tap test is the cheapest form of nondestructive test to identify the presence of this damage. However, its inconsistency and wide area of coverage can reduce its effectivity since it is carried out manually. The indigenous automated tap tester known as KETOK was used to detect the damage due to trapped voids and air pockets. The mechanism of detection is through controlling the tapping on the surface automatically at a constant rate. Another manual tap tester RD-3 from Wichitech Industries Inc. was used as reference. The acquired data was translated into damage profiling and both results were compared. The results have shown that the indigenous automated tester can profile the damage better when compared with the existing tap tester. As a conclusion, the indigenous automated tap tester has a potential to be used as an IN-SITU damage detection tool to detect delamination and disbond damage on composite panel. However, more conclusive tests need to be done in order to make the unit available to conventional users.

  20. The relationship between vickers microhardness and compressive strength of functional surface geopolymers

    Science.gov (United States)

    Subaer, Ekaputri, Januari Jaya; Fansuri, Hamzah; Abdullah, Mustafa Al Bakri

    2017-09-01

    An experimental study to investigate the relationship between Vickers microhardness and compressive strength of geopolymers made from metakaolin has been conducted. Samples were prepared by using metakaolin activated with a sodium silicate solution at a different ratio of Si to Al and Na to Al and cured at 70oC for one hour. The resulting geopolymers were stored in an open air for 28 days before conducting any measurement. Bulk density and apparent porosity of the samples were measured by using Archimedes's method. Vickers microhardness measurements were performed on a polished surface of geopolymers with a load ranging from 0.3 - 1.0 kg. The topographic of indented samples were examined by using scanning electron microscopy (SEM). Compressive strength of the resulting geopolymers was measured on the cylindrical samples with a ratio of height to the diameter was 2:1. The results showed that the molar ratios of geopolymers compositions play important roles in the magnitude of bulk density, porosity, Vickers's microhardness as well as the compressive strength. The porosity reduced exponentially the magnitude of the strength of geopolymers. It was found that the relationship between Vickers microhardness and compressive strength was linear. At the request of all authors and with the approval of the proceedings editor, article 020188 titled, "The relationship between vickers microhardness and compressive strength of functional surface geopolymers," is being retracted from the public record due to the fact that it is a duplication of article 020170 published in the same volume.

  1. Defining Assessment Literacy: Is it Different for Language Testers and Non-Language Testers?

    Science.gov (United States)

    Jeong, Heejeong

    2013-01-01

    Language assessment courses (LACs) are taught by professionals who have majored in the area of language testing (language testers or LTs), but also by others who come from different language-related majors (non-language testers, non-LTs). Different language assessment courses may be developed, depending on who teaches the course and the…

  2. Push Tester For Laminated Films

    Science.gov (United States)

    Sugimura, Russell S.

    1991-01-01

    Small instrument used to measure brittleness of polymer film adhesively bonded to hard substrate. Penlike instrument has microball tip. Small pointer in slot on side of instrument used to calibrate and indicate spring force applied by point. Microball dents only small area of specimen. Such measurements used to measure rates of embrittlement in environmental tests of candidate laminated-film covers for photovoltaic modules. Not limited to transparent films; also used on opaque laminated films on back panels of photovoltaic modules.

  3. Microstructure and hardness investigation of 17-4PH stainless steel by laser quenching

    Energy Technology Data Exchange (ETDEWEB)

    Chen Zhaoyun, E-mail: zhaoyunchenlaoshi@126.com [College of Materials Science and Chemical Engineering, Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University, Nantong ST 145, Harbin 150001 (China); Zhou Guijuan, E-mail: zgjghpx@126.com [College of Materials Science and Chemical Engineering, Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University, Nantong ST 145, Harbin 150001 (China); Chen Zhonghua, E-mail: jickdahua@163.com [College of Materials Science and Chemical Engineering, Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University, Nantong ST 145, Harbin 150001 (China)

    2012-02-01

    Highlights: Black-Right-Pointing-Pointer Surface hardening of 17-4PH is highly achieved by laser transformation hardening. Black-Right-Pointing-Pointer A hardened layer with a thickness of 1.75 mm is formed. Black-Right-Pointing-Pointer The phase similar to {epsilon}-Cu precipitates re-segregation after dissolved. Black-Right-Pointing-Pointer The strengthening phase is composed of classic lath martensite, coarse NbC and a lot of finer fcc copper-rich phases. - Abstract: Surface hardening of 17-4PH was achieved by laser transformation hardening using 5 kW continuous wave CO{sub 2} laser system. The microstructure of the laser-quenched sample was investigated by optical microscopy, transmission electron microscope and {sup 57}Fe Moessbauer spectrometer. The hardness profile was determined by a Vickers hardness tester. The hardened layer with a thickness of 1.75 mm was formed, and it was composed of classic lath martensite, coarse NbC and a lot of finer fcc copper-rich phases which were similar to {epsilon}-Cu precipitates. The maximal hardness value of hardened zone is 446 HV which is 50 HV higher than that of the substrate (386-397 HV). The higher hardness in laser transformation layer of the 17-4PH steel could be attributed to the following aspects: the matrix with a high dislocation density; the fine microstructure; the finer fcc copper-rich phases that were similar to the {epsilon}-Cu precipitates as well as the transforming of retained austenite into lath martensite.

  4. (Quickly) Testing the Tester via Path Coverage

    Science.gov (United States)

    Groce, Alex

    2009-01-01

    The configuration complexity and code size of an automated testing framework may grow to a point that the tester itself becomes a significant software artifact, prone to poor configuration and implementation errors. Unfortunately, testing the tester by using old versions of the software under test (SUT) may be impractical or impossible: test framework changes may have been motivated by interface changes in the tested system, or fault detection may become too expensive in terms of computing time to justify running until errors are detected on older versions of the software. We propose the use of path coverage measures as a "quick and dirty" method for detecting many faults in complex test frameworks. We also note the possibility of using techniques developed to diversify state-space searches in model checking to diversify test focus, and an associated classification of tester changes into focus-changing and non-focus-changing modifications.

  5. Analysis of hardness of nanocrystalline coatings of aluminum-rich ...

    Indian Academy of Sciences (India)

    The Vicker hardness was obtained by the effective model of indentation. It was observed that the hardness of the coatings decreases from 22.8–9.5 GPa with an increased nitrogen content from 1.5–4.5 sccm. Subsequently, the hardness increased to 22.1 GPa by increasing nitrogen to 6 sccm. The behavior of hardness with ...

  6. The comparison of the effects of different whitening toothpastes on the micro hardness of a nano hybrid composite resin

    Science.gov (United States)

    Nainan, Mohan Thomas; Balan, Ashok Kalappurakkal; Sharma, Roshni; Thomas, Sabeena Susan; Deveerappa, Santhosh B

    2014-01-01

    Aim: The aim of this study was to compare the micro hardness of a nanohybrid composite resin after brushing with two herbal and one non-herbal whitening toothpastes. Materials and Methods: We divided Eighty disk-shaped specimens of a nanohybrid composite (Tetric N Ceram, Ivoclar Vivadent, Asia) into 4 groups of 20 specimens each: Groups A, B, C, and D. Group A was control, Group B was brushed with Colgate total advanced whitening (Colgate-Palmolive (India) Limited), Group C with Salt and Lemon, Dabur (Dabur International Limited, Dubai, UAE), and Group D with HiOra Shine, Himalaya (The Himalaya Drug Company, India). The specimens were polished using medium, fine, and superfine discs (Sof-lex, 3M, ESPE, USA) and subsequently placed at 37°C in distilled water. They were brushed for 2 minutes twice daily with a soft motorized toothbrush (Colgate 360 sonic power battery-operated tooth brush, Colgate Palmolive, India) for 30 days. The samples were rinsed under running water to remove the toothpaste and stored in distilled water at 37°C until the readout was taken on the Vickers's hardness tester for microhardness. Results: The results revealed that the difference among the groups was statistically significant (P toothpaste had a greater impact on the microhardness of nanohybrid resin composite than herbal whitening toothpastes. PMID:25506143

  7. The comparison of the effects of different whitening toothpastes on the micro hardness of a nano hybrid composite resin.

    Science.gov (United States)

    Nainan, Mohan Thomas; Balan, Ashok Kalappurakkal; Sharma, Roshni; Thomas, Sabeena Susan; Deveerappa, Santhosh B

    2014-11-01

    The aim of this study was to compare the micro hardness of a nanohybrid composite resin after brushing with two herbal and one non-herbal whitening toothpastes. We divided Eighty disk-shaped specimens of a nanohybrid composite (Tetric N Ceram, Ivoclar Vivadent, Asia) into 4 groups of 20 specimens each: Groups A, B, C, and D. Group A was control, Group B was brushed with Colgate total advanced whitening (Colgate-Palmolive (India) Limited), Group C with Salt and Lemon, Dabur (Dabur International Limited, Dubai, UAE), and Group D with HiOra Shine, Himalaya (The Himalaya Drug Company, India). The specimens were polished using medium, fine, and superfine discs (Sof-lex, 3M, ESPE, USA) and subsequently placed at 37°C in distilled water. They were brushed for 2 minutes twice daily with a soft motorized toothbrush (Colgate 360 sonic power battery-operated tooth brush, Colgate Palmolive, India) for 30 days. The samples were rinsed under running water to remove the toothpaste and stored in distilled water at 37°C until the readout was taken on the Vickers's hardness tester for microhardness. The results revealed that the difference among the groups was statistically significant (P whitening toothpaste had a greater impact on the microhardness of nanohybrid resin composite than herbal whitening toothpastes.

  8. Armstrong Laboratory Space Visual Function Tester Program

    Science.gov (United States)

    Oneal, Melvin R.; Task, H. Lee; Gleason, Gerald A.

    1992-01-01

    Viewgraphs on space visual function tester program are presented. Many astronauts and cosmonauts have commented on apparent changes in their vision while on-orbit. Comments have included descriptions of earth features and objects that would suggest enhanced distance visual acuity. In contrast, some cosmonaut observations suggest a slight loss in their object discrimination during initial space flight. Astronauts have also mentioned a decreased near vision capability that did not recover to normal until return to earth. Duntley space vision experiment, USSR space vision experiments, and visual function testers are described.

  9. Comparative investigations of tablet crushing force testers

    DEFF Research Database (Denmark)

    Sonnergaard, Jørn; Jensen, C.G.; Poulsen, L.

    2005-01-01

    the speed of platens on the mean values or the variability was observed. It is concluded that, compared to other quality methodologies of solid dosage forms with a suspected variability, there is generally no reason to question the standard and performance of the breaking force testers used today...

  10. 21 CFR 870.3720 - Pacemaker electrode function tester.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker electrode function tester. 870.3720 Section 870.3720 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... electrode function tester. (a) Identification. A pacemaker electrode function tester is a device which is...

  11. 21 CFR 882.1410 - Electroencephalograph electrode/lead tester.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electroencephalograph electrode/lead tester. 882.1410 Section 882.1410 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Electroencephalograph electrode/lead tester. (a) Identification. An electroencephalograph electrode/lead tester is a...

  12. 21 CFR 886.1170 - Color vision tester.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Color vision tester. 886.1170 Section 886.1170...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1170 Color vision tester. (a) Identification. A color vision tester is a device that consists of various colored materials, such as colored yarns...

  13. 21 CFR 874.1090 - Auditory impedance tester.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Auditory impedance tester. 874.1090 Section 874...) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1090 Auditory impedance tester. (a) Identification. An auditory impedance tester is a device that is intended to change the air pressure in the...

  14. 21 CFR 870.2370 - Electrocardiograph surface electrode tester.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electrocardiograph surface electrode tester. 870.2370 Section 870.2370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Electrocardiograph surface electrode tester. (a) Identification. An electrocardiograph surface electrode tester is a...

  15. 21 CFR 872.1730 - Electrode gel for pulp testers.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electrode gel for pulp testers. 872.1730 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.1730 Electrode gel for pulp testers. (a) Identification. An electrode gel for pulp testers is a device intended to be applied to the surface of a tooth...

  16. 7 CFR 801.4 - Tolerances for dockage testers.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Tolerances for dockage testers. 801.4 Section 801.4... FOR GRAIN INSPECTION EQUIPMENT § 801.4 Tolerances for dockage testers. The maintenance tolerances for dockage testers used in performing official inspection services shall be: Item Tolerance Air separation ±0...

  17. Evaluation of Fracture Toughness of Tantalum Carbide Ceramic Layer: A Vickers Indentation Method

    Science.gov (United States)

    Song, Ke; Xu, Yunhua; Zhao, Nana; Zhong, Lisheng; Shang, Zhao; Shen, Liuliu; Wang, Juan

    2016-07-01

    A tantalum carbide (TaC) ceramic layer was produced on gray cast iron matrix by in situ technique comprising a casting process and a subsequent heat treatment at 1135 °C for 45 min. Indentation fracture toughness in TaC ceramic layer was determined by the Vickers indentation test for various loads. A Niihara approach was chosen to assess the fracture toughness of TaC ceramic layer under condition of the Palmqvist mode in the experiment. The results reveal that K IC evaluation of TaC ceramic layer by the Vickers indentation method strongly depends on the selection of crack system and K IC equations. The critical indentation load for Vickers crack initiation in TaC ceramic layer lies between 1 and 2 N and the cracks show typical intergranular fracture characteristics. Indentation fracture toughness calculated by the indentation method is independent of the indentation load on the specimen. The fracture toughness of TaC ceramic layer is 6.63 ± 0.34 MPa m1/2, and the toughening mechanism is mainly crack deflection.

  18. A new technique to make transparent teeth without decalcifying: description of the methodology and micro-hardness assessment.

    Science.gov (United States)

    Malentacca, Augusto; Lajolo, Carlo

    2015-01-01

    Diaphanisation and other in vitro endodontic models (i.e., plastic blocks, micro-CT reconstruction, computerised models) do not recreate real root canal working conditions: a more realistic endodontic model is essential for testing endodontic devices and teaching purposes. The aim of this study was to describe a new technique to construct transparent teeth without decalcifying and evaluate the micro-hardness of so treated teeth. Thirty freshly extracted teeth were randomly divided into three groups as follows: 10 non-treated teeth (4 molars, 3 premolars, 3 incisors; control group - G1), 10 teeth were diaphanised (4 molars, 4 premolars, 2 incisors - G2) and 10 teeth were treated with the new proposed technique (2 molars, 6 premolars, 2 incisors - G3). Vickers hardness tester (MHT-4 and AxioVision microscope, Carl Zeiss, 37030 Gottingen, Germany - load=50 g, dwell time=20s, slope=5, 50× magnification) was used to determine microhardness (Vickers Hardness Number - VHN). Statistical analysis was performed using the Intercooled Stata 8.0 software (Stata Corporation, College Station, TX, USA). Only groups 1 and 3 could be tested for hardness because diaphanised teeth were too tender and elastic. Differences in enamel VHN were observed between G1 (mean 304.29; DS=10.44; range 283-321) and G3 (mean 318.51; DS=14.36; range 295.5-339.2) - (p<0.05); differences in dentine VHN were observed between G1 (mean 74.73; DS=6.62; range 63.9-88.1) and G3 (mean 64.54; DS=5.55; range 51.2-72.3) - (p<0.05). G3 teeth presented a slightly lower VHN compared to G1, probably due to some little structural differences among groups, and were dramatically harder than the diaphanised teeth. The described technique, thus, can be considered ideal for testing endodontic instruments and for teaching purposes. Copyright © 2014 Elsevier GmbH. All rights reserved.

  19. Small-Bolt Torque-Tension Tester

    Science.gov (United States)

    Posey, Alan J.

    2009-01-01

    The device described here measures the torque-tension relationship for fasteners as small as #0. The small-bolt tester consists of a plate of high-strength steel into which three miniature load cells are recessed. The depth of the recess is sized so that the three load cells can be shimmed, the optimum height depending upon the test hardware. The three miniature load cells are arranged in an equilateral triangular configuration with the test bolt aligned with the centroid of the three. This is a kinematic arrangement.

  20. Portable computerized tester improves flight-line maintenance

    Science.gov (United States)

    Grinberg, Y.

    1985-11-01

    The present general purpose and portable Computerized Organizational Level Tester (COLT) for the flight-line maintenance of advanced weapons systems is in effect a fully functioning replica of contemporary automated test equipment architectures previously available only in laboratory test installations. The COLT's automated equipment architecture has been scaled down to a ruggedized, portable, suitcase-sized field tester for both analog and digital equipment. Tester software is designed to minimize programming effort, and possesses a real time executive kernel which transparently interfaces high level user commands with tester hardware. Automatic software-generation tools are incorporated.

  1. Intra-tester and inter-tester reliability of chest expansion measurement in clients with ankylosing spondylitis and healthy individuals.

    Science.gov (United States)

    Sharma, Jagannath; Senjyu, Hideaki; Williams, Linda; White, Colin

    2004-01-01

    The purpose of this study was to examine the intra-tester and inter-tester reliability of chest expansion (CE) using a tape measure, in people with ankylosing spondylitis (AS) and healthy subjects. Twenty-two subjects with AS with a mean age of 41.4 years and 25 healthy subjects with a mean age of 41.0 years were tested in two arm positions: hands on head and arms at the sides, the tape measure being placed at the level of xiphisternum. There were three testers for subjects with AS and two testers for healthy subjects. Three trials in both arm positions were recorded by each tester on two separate occasions which were 10 minutes apart. Results showed intraclass correlation coefficients (ICC) for intra-tester reliability good (0.85 to 0.97) across the occasions. Intraclass correlation coefficients for inter-tester reliability were also very good (0.93 to 0.97). As reliability is good it is suggested that CE can be used for monitoring disease progression and efficacy of intervention with confidence within tester and between testers.

  2. Vickers microhardness comparison of 4 composite resins with different types of filler.

    Directory of Open Access Journals (Sweden)

    René García-Contreras

    2015-10-01

    Full Text Available Composite resins are the material of choice to restore minimal invasive cavities; conversely, it is important to explore the mechanical properties of commercially available dental materials. Objective: To compare the Vickers microhardness (VHN of four available commercial composite resins using standardized samples and methods. Methodology: Composite cylinders were manufactured in a Teflon mould. We used the follow composite resins (n=4/gp: Microhybrid resins [Feeling Lux (Viarden and Amelogen Plus (Ultradent], Hybrid resin [Te-Econom Plus (Ivoclar] and Nanohybrid resin [Filtek Z350 (3M ESPE]. All samples were incubated in distilled water at 37ºC for five days. The test was carried out with microhardness indenter at 10 N, and a dwelling time of 10 s for 9 indentations across the specimens resulting in a total of 36 indentations for each group. Data were subjected to Kolmogorov-Smirnov normality test and ANOVA (post-hoc Tukey test. Results: The VHN mean values ranged from harder to softer as follows: Filtek Z350 (71.96±6.44 (p Amelogen Plus (59.90±4.40 (p Feeling lux (53.52±5.72> Te-Econom Plus (53.26±5.19. Conclusion: According to our results, the microhardness of the evaluated conventional composite resins can withstand the masticatory forces; however nanohybrid composite resins showed better Vickers microhardness and therefore are a more clinically suitable option for minimal invasion treatments.

  3. Ny generasjon HPV-tester på vent

    OpenAIRE

    Sørbye, Sveinung Wergeland; Gutteberg, Tore Jarl; Vintermyr, Olav Karsten

    2010-01-01

    Ny forskning viser at gentester for humant papillomvirus (HPV) siler ut de behandlingstrengende i langt større grad enn celleprøver. Samtidig er det grunn til å tro at mRNA-tester bør velges fremfor DNA-tester.

  4. Systematic hardness measurements on CsClxBr(1–x) and ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Vickers hardness measurements have been made on polycrystalline blanks of CsClxBr(1–x) and single crystals of NH4ClxBr(1–x). The composition dependence of hardness is highly nonlinear in both systems and follows an empirical model that includes a lattice contribution and a disorder contribution.

  5. An investigation to examine the inter-tester and intra-tester reliability of the Rolimeter ® knee tester, and its sensitivity in identifying knee joint laxity

    National Research Council Canada - National Science Library

    Hatcher, Alison; Hatcher, Julian; Arbuthnot, Jamie; McNicholas, Mike

    2005-01-01

    The purpose of this study is to evaluate the Rolimeter knee tester (Aircast, Europe) as reliable and clinically sensitive tool for identifying and quantifying knee joint laxity utilising a sample of both known ACLD and normal knees...

  6. Operating manual for the miniservo-control tester

    Science.gov (United States)

    Rapp, W.L.

    1986-01-01

    Ever since the implementation of servo-control units (regular and minimodels) with manometers at U. S. Geological Survey streamflow stations, the need for an effective and efficient servo-control unit tester has been paramount among field personnel. In numerous cases, servo-control unit failures were blamed on battery failures and vice versa. There was no valid instrument to definitively identify cause of failure, let alone properly diagnose the servo-control/manometer system. In 1983, two servo-control unit testers were developed and fabricated. One was mechanical in fabrication, operation, and serviceability; the other was electronic. The testers were extensively used and evaluated in Maine, Ohio, Kansas, and Louisiana under a wide range of environmental conditions. The consensus to integrate the best aspects of both testers into one instrument allowed the Survey to finally solve its long-time need for an effective, efficient servo-control unit tester. (USGS)

  7. Assessment of elemental composition, microstructure, and hardness of stainless steel endodontic files and reamers.

    Science.gov (United States)

    Darabara, Myrsini; Bourithis, Lefteris; Zinelis, Spiros; Papadimitriou, George D

    2004-07-01

    The purpose of this study was to determine the elemental composition, microstructure, and hardness of commercially available reamers, K files, and H files. Five instruments of each type from different manufacturers (Antaeos, FKG, Maillefer, Mani, and Micromega) were embedded in epoxy resin along their longitudinal axis. After metallographic grinding and polishing, the specimens were chemically etched and their microstructure investigated under an incident light microscope. The specimens were studied under a scanning electron microscope, and their elemental compositions were determined by energy dispersive X-ray microanalysis. The same surfaces were repolished and X-ray diffraction was performed. The same specimen surface was used for the assessment of the Vickers hardness (HV200) by using a microhardness tester with a 200-g load and 20-s contact time. The hardness results were statistically analyzed with two-way ANOVA and Tukey's test (a = 0.05). All files demonstrated extensively elongated grains parallel to longitudinal file axis because of cold drawing. The elemental composition of Maillefer and Mani reamers, Antaeos K files, and Mani H files were found in the range of AISI 303 SS, whereas all the rest were determined as AISI 304 SS. Two different phases (austenite SSt and martensite SSt) were identified with X-ray diffraction for all files tested. The results of hardness classified reamers in the following decreasing order (HMV200): Micromega = 673 +/- 29, Mani = 662 +/- 24, Maillefer = 601 +/- 34, Antaeos = 586 +/- 18, FKG = 557 +/- 19, and the K files (HV200): FKG = 673 +/- 16, Mani = 647 +/- 19, Maillefer = 603 +/- 41, Antaeos = 566 +/- 21, Micromega = 555 +/- 15, and the H files (HMV200): Mani = 640 +/- 12, FKG = 583 +/- 31, Maillefer = 581 +/- 5, Antaeos = 573 +/- 3, Micromega = 546 +/- 14. Although only two stainless steel alloys were used for the production of endodontic files, the differences in hardness are independent to the alloys used, implying that

  8. An investigation to examine the inter-tester and intra-tester reliability of the Rolimeter knee tester, and its sensitivity in identifying knee joint laxity.

    Science.gov (United States)

    Hatcher, Julian; Hatcher, Alison; Arbuthnot, Jamie; McNicholas, Mike

    2005-11-01

    The purpose of this study is to evaluate the Rolimeter knee tester (Aircast, Europe) as reliable and clinically sensitive tool for identifying and quantifying knee joint laxity utilising a sample of both known ACLD and normal knees. Thirty matched subjects (15 known ACLD and 15 normal subjects) were tested for knee joint laxity using the Rolimeter. Each subject was measured at both 90 degrees and 30 degrees of knee flexion, by each of the six investigators. This was then repeated again by all six investigators so that inter-tester and intra-tester reliability could be examined. Results showed that there was good reliability between testers, and intra-tester reliability was good for both left and right knees in both 90 degrees and 30 degrees of flexion. Results also demonstrated a high level of sensitivity for determining knee joint laxity in ACLD compared to normal knees. The Rolimeter knee tester is a reliable device for quantifying knee joint laxity, and is sensitive enough to identify anterior cruciate ligament deficiency.

  9. Sixty-four-Channel Inline Cable Tester

    Science.gov (United States)

    2008-01-01

    Faults in wiring are a serious concern for the aerospace and aeronautics (commercial, military, and civil) industries. A number of accidents have occurred because faulty wiring created shorts or opens that resulted in the loss of control of the aircraft or because arcing led to fires and explosions. Some of these accidents have resulted in the massive loss of lives (such as in the TWA Flight 800 accident). Circuits on the Space Shuttle have also failed because of faulty insulation on wiring. STS-93 lost power when a primary power circuit in one engine failed and a second engine had a backup power circuit fault. Cables are usually tested on the ground after the crew reports a fault encountered during flight. Often such failures result from vibration and cannot be replicated while the aircraft is stationary. It is therefore important to monitor faults while the aircraft is in operation, when cables are more likely to fail. Work is in progress to develop a cable fault tester capable of monitoring up to 64 individual wires simultaneously. Faults can be monitored either inline or offline. In the inline mode of operation, the monitoring is performed without disturbing the normal operation of the wires under test. That is, the operations are performed unintrusively and are essentially undetectable for the test signal levels are below the noise floor. A cable can be monitored several times per second in the offline mode and once a second in the inline mode. The 64-channel inline cable tester not only detects the occurrence of a fault, but also determines the type of fault (short/open) and the location of the fault. This will enable the detection of intermittent faults that can be repaired before they become serious problems.

  10. Hardness of basaltic glass-ceramics

    DEFF Research Database (Denmark)

    Jensen, Martin; Smedskjær, Morten Mattrup; Estrup, Maja

    2009-01-01

    The dependence of the hardness of basaltic glass-ceramics on their degree of crystallisation has been explored by means of differential scanning calorimetry, optical microscopy, x-ray diffraction, and Vickers indentation. Different degrees of crystallisation in the basaltic glasses were achieved...... by varying the temperature of heat treatment. The predominant crystalline phase in the glass was identified as augite. It was found that the hardness of the glass phase decreased slightly with an increase in the degree of crystallisation, while that of the augite phase drastically decreased....

  11. Dynamic tester for rotor seals and bearings

    Science.gov (United States)

    Vonpragenau, George L. (Inventor)

    1993-01-01

    A dynamic tester for testing vibration damping seals and bearings is constructed having a hollow shaft extending through the seal or bearing, with the shaft internally supported at each end by fluid bearings on hollow bosses connected to an interior of an enclosure, with no rolling members connected to the shaft is described. A high pressure working fluid is forced through the hollow bosses to operate the bearings. Additionally, the shaft is provided with a reaction turbine that angularly vents a portion of the high pressure working fluid in order to rotate the shaft at high speed, up to 40,000 rpm. The seal or bearing is mounted in a bushing, in turn supported by rods to a shaking device that vibrates the seal or bearing as the shaft is rotated. A plurality of proximity sensors are mounted from outside the enclosure to sense shaft and seal bushing vibrations, and a plurality of pressure ports are disposed in the enclosure to allow sensing of dynamic and static pressures of the testing apparatus.

  12. Influence of 1,3,6 naphthalene trisulfonic acid on microstructure & hardness in electrodeposited Ni-layers

    DEFF Research Database (Denmark)

    Rasmussen, Anette Alsted; Møller, Per; Somers, Marcel A. J.

    2002-01-01

    The influence of the additive 1,3,6 naphthalene trisulfonic acid on the microstructure and hardness of electrodeposited nickel layers was investigated. The microstructure was characterized using transmission electron microscopy; the Vickers hardness was measured in cross sections. The additive wa...

  13. A new approach to the estimation of surface free energy based on Vickers microhardness data

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available A relation between surface free energy (σMHV and Meyer’s lines cut-values has been established using Vickers microhardness (MHV method and empirical physical laws. This relation allows the calculation of σMHV only from MHV data. The parameters required are Meyer’s lines cut-values and the mean value of diagonal length of the impression at different loads applied (drealmean. Our study of 12 samples of ultra high molecular weight polyethylene (PE-UHMW showed that the new approach is applicable when the slope value of Meyer’s lines equals 2 (i.e. n = 2. A γ-60Co source was used for the irradiation of 11 samples (one of the samples investigated is un-irradiated at room temperature in air. Doses of 1, 2, 5, 10, 20, 50, 100, 200, 500, 1000 and 1500 kGy were applied. The values of σMHV obtained are in a good agreement with the literature. The dependence of σMHV on the dose applied strictly corresponds to the radiation effects theory. MHV was measured at seven different loads – 0.0123, 0.0245, 0.049, 0.098, 0.196, 0.392, 0.785 N at a loading time of 30 s.

  14. Evaluation by Vickers indentation of fracture toughness of a phosphate biodegradable glass.

    Science.gov (United States)

    Clément, J; Torres, P; Gil, F J; Planell, J A; Terradas, R; Martinez, S

    1999-07-01

    Indentation tests are commonly used for the evaluation of fracture toughness of brittle materials, particularly glasses and ceramics, because this technique requires only a small polished area on the specimen surface from which a large number of data points can be generated rapidly. However, a wide variety of equations for the calculation of fracture toughness of ceramic materials by means of Vickers indentation are available. Such equations are obtained phenomenologically and their parameters adjusted in such a way that the KIC values obtained are in good agreement with those obtained by conventional methods. This is the reason why it is necessary to check which type of equation reproduces more accurately the results obtained by means of conventional methods for the material which is going to be investigated. In the present work seven different fracture toughness equations widely used in glass and ceramic studies are considered and the results are compared with those obtained by conventional methods, such as single-edge notch beam (SENB) specimens tested in three-point bending. The role played by the applied indentation load is considered. Copyright 1999 Kluwer Academic Publishers

  15. CONDENSED MATTER: STRUCTURE, MECHANICAL AND THERMAL PROPERTIES: Theoretical Hardness of Wurtzite-Structured Semiconductors

    Science.gov (United States)

    Guo, Xiao-Ju; Xu, Bo; Liu, Zhong-Yuan; Yu, Dong-Li; He, Ju-Long; Guo, Li-Cong

    2008-06-01

    Vickers hardness calculations of eleven wurtzite-structured semiconductors are performed based on the microscopic hardness model. All the parameters are obtained from first-principles calculations. There are two types of chemical bonds in wurtzite-structured crystals. The overlap populations of the two types of chemical bonds in lonsdaleite are chosen as Pc for wurtzite structure. The calculated bond ionicity values of the wurtzite-structured semiconductors are in good agreement with the ionicities from the dielectric definition. When the hardness of wurtzite-structured crystal is higher than 20GPa, our calculated Vickers hardness is within 10% accuracy. Therefore, the hardness of novel wurtzite-structured crystal could be estimated from first-principles calculations.

  16. Prediction of the Vickers Microhardness and Ultimate Tensile Strength of AA5754 H111 Friction Stir Welding Butt Joints Using Artificial Neural Network.

    Science.gov (United States)

    De Filippis, Luigi Alberto Ciro; Serio, Livia Maria; Facchini, Francesco; Mummolo, Giovanni; Ludovico, Antonio Domenico

    2016-11-10

    A simulation model was developed for the monitoring, controlling and optimization of the Friction Stir Welding (FSW) process. This approach, using the FSW technique, allows identifying the correlation between the process parameters (input variable) and the mechanical properties (output responses) of the welded AA5754 H111 aluminum plates. The optimization of technological parameters is a basic requirement for increasing the seam quality, since it promotes a stable and defect-free process. Both the tool rotation and the travel speed, the position of the samples extracted from the weld bead and the thermal data, detected with thermographic techniques for on-line control of the joints, were varied to build the experimental plans. The quality of joints was evaluated through destructive and non-destructive tests (visual tests, macro graphic analysis, tensile tests, indentation Vickers hardness tests and t thermographic controls). The simulation model was based on the adoption of the Artificial Neural Networks (ANNs) characterized by back-propagation learning algorithm with different types of architecture, which were able to predict with good reliability the FSW process parameters for the welding of the AA5754 H111 aluminum plates in Butt-Joint configuration.

  17. Prediction of the Vickers Microhardness and Ultimate Tensile Strength of AA5754 H111 Friction Stir Welding Butt Joints Using Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Luigi Alberto Ciro De Filippis

    2016-11-01

    Full Text Available A simulation model was developed for the monitoring, controlling and optimization of the Friction Stir Welding (FSW process. This approach, using the FSW technique, allows identifying the correlation between the process parameters (input variable and the mechanical properties (output responses of the welded AA5754 H111 aluminum plates. The optimization of technological parameters is a basic requirement for increasing the seam quality, since it promotes a stable and defect-free process. Both the tool rotation and the travel speed, the position of the samples extracted from the weld bead and the thermal data, detected with thermographic techniques for on-line control of the joints, were varied to build the experimental plans. The quality of joints was evaluated through destructive and non-destructive tests (visual tests, macro graphic analysis, tensile tests, indentation Vickers hardness tests and t thermographic controls. The simulation model was based on the adoption of the Artificial Neural Networks (ANNs characterized by back-propagation learning algorithm with different types of architecture, which were able to predict with good reliability the FSW process parameters for the welding of the AA5754 H111 aluminum plates in Butt-Joint configuration.

  18. Prediction of the Vickers Microhardness and Ultimate Tensile Strength of AA5754 H111 Friction Stir Welding Butt Joints Using Artificial Neural Network

    Science.gov (United States)

    De Filippis, Luigi Alberto Ciro; Serio, Livia Maria; Facchini, Francesco; Mummolo, Giovanni; Ludovico, Antonio Domenico

    2016-01-01

    A simulation model was developed for the monitoring, controlling and optimization of the Friction Stir Welding (FSW) process. This approach, using the FSW technique, allows identifying the correlation between the process parameters (input variable) and the mechanical properties (output responses) of the welded AA5754 H111 aluminum plates. The optimization of technological parameters is a basic requirement for increasing the seam quality, since it promotes a stable and defect-free process. Both the tool rotation and the travel speed, the position of the samples extracted from the weld bead and the thermal data, detected with thermographic techniques for on-line control of the joints, were varied to build the experimental plans. The quality of joints was evaluated through destructive and non-destructive tests (visual tests, macro graphic analysis, tensile tests, indentation Vickers hardness tests and t thermographic controls). The simulation model was based on the adoption of the Artificial Neural Networks (ANNs) characterized by back-propagation learning algorithm with different types of architecture, which were able to predict with good reliability the FSW process parameters for the welding of the AA5754 H111 aluminum plates in Butt-Joint configuration. PMID:28774035

  19. Synthesis, growth, optical, mechanical and electrical properties of L ...

    Indian Academy of Sciences (India)

    Ne laser source. Mechanical property of the crystal was determined by Vickers hardness tester. The frequency and temperature dependence of dielectric constant (r), dielectric loss (tan ) and a.c. conductivity (ac) were also measured.

  20. Control of the valve system of multicyclic bed testers

    Energy Technology Data Exchange (ETDEWEB)

    Lopatkin, O.P.; Varlamov, P.S.

    1980-01-01

    It has been established that in testing beds with the help of multicyclic testers in twisted wells, the height of lifting the pipes for closure of the valve should be determined with regard for the resistance forces during movement of the drilling pipe string. A plan is presented for the pipe shaft with lowered drilling string after installation of the packer. The technique developed in the North Caucasus Scientific Research and Planning Institute of the Oil Industry will make it possible to determine for deep twisted wells the height of lifting of the string drilling pipes needed to close the safety valve of the multicyclic bed tester.

  1. Identification of the chromosomes of the rye translocation tester set.

    Science.gov (United States)

    Sybenga, J; van Eden, J; van der Meijs, Q G; Roeterdink, B W

    1985-05-01

    Intercrossing the Wageningen translocation tester set of rye and the series of 'Imperial' rye additions to 'Chinese Spring' wheat of Sears yielded 29 chromosome disomic translocation hybrids. Observation of trivalents led to the identification of the chromosomes of the tester set in terms of the terminology system used in the Triticinae. The analysis was complicated by very low chiasma frequencies in some short chromosome segments in the hybrids. Nevertheless, it could be safely concluded that 1R=VII; 2R=III; 3R=II; 4R=IV; 5R=VI; 6R=V; 7R=I, which deviates slightly from previous classifications based on other methods.

  2. Etiske utfordringer med non-invasive prenatale tester (NIPT)

    OpenAIRE

    Bjørn Hofmann

    2014-01-01

    Analyser av cellefritt DNA fra foster i gravide kvinners blod gir nye muligheter innen fosterdiagnostikk: Testene er bedre enn eksisterende tester, de reduserer risikoen og er billigere. Flere land har tatt i bruk disse testene, og Helsedirektoratet i Norge har mottatt søknad om å ta i bruk en test som erstatter tidlig ultralyd og blodprøver. Likevel nøler norske myndigheter. Hvorfor gjør de det? Ett av svarene er at non-invasive prenatale tester fører med seg en rekke faglige og moralske spø...

  3. Influence of temperature, grain size and cobalt content on the hardness of WC-Co alloys

    CSIR Research Space (South Africa)

    Milman, YV

    1999-01-01

    Full Text Available The Vickers hardness of WC-Co alloys has been measured at temperatures ranging from -196 to 900 degrees C. The cobalt content of the alloys ranged from 10 to 24 vol% and the grain size from 0.5 to 2.3 um. It was found that, at all cobalt contents...

  4. Crystallographic Analysis of Nucleation at Hardness Indentations in High-Purity Aluminum

    DEFF Research Database (Denmark)

    Xu, Chaoling; Zhang, Yubin; Lin, Fengxiang

    2016-01-01

    Nucleation at Vickers hardness indentations has been studied in high-purity aluminum cold-rolled 12 pct. Electron channeling contrast was used to measure the size of the indentations and to detect nuclei, while electron backscattering diffraction was used to determine crystallographic orientation...

  5. Software testing an ISTQB-BCS certified tester foundation guide

    CERN Document Server

    Hambling, Brian; Samaroo, Angelina; Thompson, Geoff; Williams, Peter; Hambling, Brian

    2015-01-01

    This practical guide provides insight into software testing, explaining the basics of the testing process and how to perform effective tests. It provides an overview of different techniques and how to apply them. It is the best-selling official textbook of the ISTQB-BCS Certified Tester Foundation Level.

  6. In vitro laxity-testers for knee joints of mice

    NARCIS (Netherlands)

    Blankevoort, L.; van Osch, G. J.; Janssen, B.; Hekman, E. E.

    1996-01-01

    The knee joints of mice can be used as a model for studying the effects of interventions on knee laxity. The goal of this study was to quantify knee joint laxity in vitro. Three devices were developed: a positioning- and cementing device, an anterior-posterior (AP) laxity tester and a varus-valgus

  7. An automated data collection system for a Charpy impact tester

    Science.gov (United States)

    Weigman, Bernard J.; Spiegel, F. Xavier

    1993-01-01

    A method for automated data collection has been developed for a Charpy impact tester. A potentiometer is connected to the pivot point of the hammer and measures the angular displacement of the hammer. This data is collected with a computer and, through appropriate software, accurately records the energy absorbed by the specimen. The device can be easily calibrated with minimal effort.

  8. Colour of Tester Effects on Children's Expressed Attitudes.

    Science.gov (United States)

    Thomas, K. C.

    1978-01-01

    Discusses a study of student attitudes, preferences, and stereotyping among White Britons and West Indian students in an English secondary school. Findings indicated that factors such as the race of the tester influenced the test situation. For journal availability, see SO 506 785. (DB)

  9. Role of elastic deformation in determining the mixed alkaline earth effect of hardness in silicate glasses

    DEFF Research Database (Denmark)

    Kjeldsen, Jonas; Smedskjær, Morten Mattrup; Potuzak, M.

    2015-01-01

    Glasses deform permanently as a result of indentation and the total resistance to deformation consists of three individual resistances, i.e., those to elastic deformation, densification, and plastic flow. The link between Vickers hardness and the resistances to densification and plastic flow has...... been investigated previously, but the link between the resistance to elastic deformation and hardness has not yet been studied. In this work, we investigate the link between elastic deformation during indentation and Vickers hardness in a series of mixed magnesium-barium boroaluminosilicate glasses. We...... show that the mixed alkaline earth effect manifests itself as deviations from linearity in shear modulus, Poisson’s ratio, glass transition temperature, liquid fragility index, hardness, volume of densification, and volume of plastic flow. We find no correlation between the elastic part...

  10. 77 FR 64588 - Highway Safety Programs; Conforming Products List of Calibrating Units for Breath Alcohol Testers

    Science.gov (United States)

    2012-10-22

    ... of Calibrating Units for Breath Alcohol Testers AGENCY: National Highway Traffic Safety... conform to the Model Specifications for Calibrating Units for Breath Alcohol Tester (CUs) dated, June 25...) published a standard for Calibrating Units for Breath Alcohol Testers. A Qualified Products List of...

  11. 49 CFR 180.409 - Minimum qualifications for inspectors and testers.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Minimum qualifications for inspectors and testers... Minimum qualifications for inspectors and testers. (a) Except as otherwise provided in this section, any... employer retains a copy of the tester's qualifications with the documents required by § 180.417(b). [Amdt...

  12. Limestone Powders Yielding and Steady State Resistance under shearing with different testers

    NARCIS (Netherlands)

    Shi, Hao; Luding, Stefan; Magnanimo, Vanessa

    2016-01-01

    We study the effect of both particle size and shear testers on the failure (yielding) and the steady state shear strength of granular materials. Physical experiments are carried out on four fine limestone powders using a geotechnical direct shear tester and the standard Schulze ring shear tester to

  13. The structure and hardness of the highest boride of tungsten, a borophene-based compound.

    Science.gov (United States)

    Gonzalez Szwacki, Nevill

    2017-06-22

    Two-dimensional systems have strengthened their position as a key materials for novel applications. Very recently, boron joined the distinguished group of elements confirmed to possess 2D allotropes, named borophenes. In this work, we explore the stability and hardness of the highest borides of tungsten, which are built of borophenes separated by metal atoms. We show that the WB3+x compounds have Vickers hardnesses approaching 40 GPa only for small values of x. The insertion of extra boron atoms is, in general, detrimental to the hardness of WB3 because it leads to the formation of quasi-planar boron sheets that are less tightly connected with the adjacent tungsten layers. Very high concentrations of boron (x ≈ 1), give rise to a soft (Vickers hardness of ~8 GPa) and unstable hP20-WB4 structure that can be considered to be built of quasi-planar boron α-sheets separated by graphitic tungsten layers. By contrast, we show that the formation of tungsten vacancies leads to structures, e.g. W0.75B3+x , with Vickers hardnesses that are not only similar in value to the experimentally reported load-independent hardnesses greater than 20 GPa, but are also less sensitive to variations in the boron content.

  14. Hardness and incipient plasticity in silicate glasses

    DEFF Research Database (Denmark)

    Kjeldsen, Jonas; Smedskjær, Morten Mattrup; Mauro, John C.

    2014-01-01

    The scaling of Vickers hardness (Hv) in oxide glasses with varying network modifier/modifier ratio is manifested as either a positive or negative deviation from linearity with a maximum deviation at the ratio of about 1:1. In an earlier study [J. Kjeldsen et al., J. Non-Cryst. Solids 369,61(2013)......The scaling of Vickers hardness (Hv) in oxide glasses with varying network modifier/modifier ratio is manifested as either a positive or negative deviation from linearity with a maximum deviation at the ratio of about 1:1. In an earlier study [J. Kjeldsen et al., J. Non-Cryst. Solids 369......,61(2013)], we observed a minimum ofHv in CaO/MgO sodium aluminosilicate glasses at CaO/MgO = 1:1 and postulated that this minimum is linked to a maximum in plastic flow. However, the origin of this link has not been experimentally verified. In this work, we attempt to do so by exploring the links among Hv......, volume recovery ratio (VR), and plastic deformation volume (VP) under indentation, glass transition temperature (Tg), Young’s modulus (E), and liquid fragility index (m) in CaO/MgO and CaO/Li2O sodium aluminosilicate glasses. We confirm the negative deviations from linearity and find that the maximum...

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

    Energy Technology Data Exchange (ETDEWEB)

    Manika, Ilze; Maniks, Janis [Institute of Solid State Physics, University of Latvia, 8 Kengaraga Str., Riga LV1063 (Latvia)], E-mail: manik@latnet.lv

    2008-04-07

    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 h{sub c}, below which the substrate has a negligible effect on the hardness, was estimated from the experimentally obtained hardness versus indentation depth curves. The results show a marked effect of the coating structure on the size of the influence zone beneath the indenter. The indentation depth limits were found to increase in the row of single crystal {yields} polycrystalline {yields} amorphous coatings. The obtained indentation depth criteria are compared with the reference data obtained by using finite element and kinematic calculations.

  16. Non-Intrusive Impedance-Based Cable Tester

    Science.gov (United States)

    Medelius, Pedro J. (Inventor); Simpson, Howard J. (Inventor)

    1999-01-01

    A non-intrusive electrical cable tester determines the nature and location of a discontinuity in a cable through application of an oscillating signal to one end of the cable. The frequency of the oscillating signal is varied in increments until a minimum, close to zero voltage is measured at a signal injection point which is indicative of a minimum impedance at that point. The frequency of the test signal at which the minimum impedance occurs is then employed to determine the distance to the discontinuity by employing a formula which relates this distance to the signal frequency and the velocity factor of the cable. A numerically controlled oscillator is provided to generate the oscillating signal, and a microcontroller automatically controls operation of the cable tester to make the desired measurements and display the results. The device is contained in a portable housing which may be hand held to facilitate convenient use of the device in difficult to access locations.

  17. RETROFIT OF A ROLLER BRAKE TESTER AT FAMENA

    OpenAIRE

    Božić, Mladen; Vučetić, Ante; Ilinčić, Petar; Lulić, Zoran

    2014-01-01

    The vehicle brake tester described in this paper is placed in the Laboratory for IC Engines and Motor Vehicles at the Faculty of Mechanical Engineering and Naval Architecture (FAMENA) in Zagreb. As the device, built in 1983, was inoperative, a decision was made for retrofit rather than repair. The retrofit included a reconstruction of some parts and modification of the braking force measurement. Adaptation of monitoring and control was made on electronic components that control the roller set...

  18. In-Place Filter Tester Instrument for Nuclear Material Containers.

    Science.gov (United States)

    Brown, Austin D; Moore, Murray E; Runnels, Joel T; Reeves, Kirk

    2016-05-01

    A portable instrument was developed to determine filter clogging and container leakage of in-place nuclear material storage canisters. This paper describes the development of an in-place filter tester for determining the "as found" condition of unopened canisters. The U.S. Department of Energy uses several thousand canisters for nuclear material storage, and air filters in the canister lids allow gases to escape while maintaining an equilibrated pressure without release of radioactive contamination. Diagnosing the filter condition and canister integrity is important for ensuring worker and public safety. Customized canister interfaces were developed for suction clamping (during tests) to two of the canister types in use at Los Alamos National Laboratory. Experimental leakage scenarios included: O-rings fouled with dust, cracked O-rings, and loose canister lids. The prototype tester has a measurement range for air leakage rates from 8.2 × 10 mL s up to 3.0 × 10 mL s. This is sufficient to measure a leak rate of 3.4 × 10 mL s, which is the Los Alamos helium leak criterion for post-drop tested canisters. The In-Place-Filter-Tester cannot measure to the lower value of the helium leak criterion for pre-drop tested canisters (1.0 × 10 mL s). However, helium leak testing requires canister disassembly, while the new in-place filter tester is able to assess the assembled condition of as-found and in-situ canisters.

  19. Computational Fluid Dynamics Analysis of the Venturi Dustiness Tester.

    Science.gov (United States)

    Dubey, Prahit; Ghia, Urmila; Turkevich, Leonid A

    2017-05-01

    Dustiness quantifies the propensity of a finely divided solid to be aerosolized by a prescribed mechanical stimulus. Dustiness is relevant wherever powders are mixed, transferred or handled, and is important in the control of hazardous exposures and the prevention of dust explosions and product loss. Limited quantities of active pharmaceutical powders available for testing led to the development (at University of North Carolina) of a Venturi-driven dustiness tester. The powder is turbulently injected at high speed (Re ~ 2 × 104) into a glass chamber; the aerosol is then gently sampled (Re ~ 2 × 103) through two filters located at the top of the chamber; the dustiness index is the ratio of sampled to injected mass of powder. Injection is activated by suction at an Extraction Port at the top of the chamber; loss of powder during injection compromises the sampled dustiness. The present work analyzes the flow inside the Venturi Dustiness Tester, using an Unsteady Reynolds-Averaged Navier-Stokes formulation with the k-ω Shear Stress Transport turbulence model. The simulation considers single-phase flow, valid for small particles (Stokes number Stk tester before the Sampling Phase begins. Dispersion of the powder during the Injection Phase results in a uniform aerosol inside the tester, even for inhomogeneous injections, satisfying a necessary condition for the accurate evaluation of dustiness. Simulations are also performed under the conditions of reduced Extraction-Port flow; results confirm the importance of high Extraction-Port flow rate (standard operation) for uniform distribution of fluid tracers. Simulations are also performed under the conditions of delayed powder injection; results show that a uniform aerosol is still achieved provided 0.5 s elapses between powder injection and sampling.

  20. Design and development of seal components fatigue tester

    OpenAIRE

    P. Czop; D. Sławik; G. Wszołek; M. Związek

    2008-01-01

    Purpose: The aim of the paper is research and development concerning a fatigue tester of shock absorber seal systems.Design/methodology/approach: Analytical approach has been applied to get an understanding of a heat exchange process. The mathematical model has been formulated and validated based on the available measurements. Numerical simulation has been carried out to illustrate a heat exchange process performance.Findings: It is possible to control a seal temperat...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-12-31

    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.

  2. DETERMINATION OF VICKERS MICROHARDNESS IN β-Ga2O3 SINGLE CRYSTALS GROWN FROM THEIR OWN MELT

    Directory of Open Access Journals (Sweden)

    L. I. Guzilova

    2015-05-01

    Full Text Available The results of microhardness measurements of β-Ga2O3 single crystals for (001 crystallographic face are reported. The crystals were grown by the free crystallization with the "Garnet-2M" equipment. Microhardness values ​​ were determined by the Vickers method at varying loads. A four-sided diamond pyramid was used as an indenter. The average value of gallium oxide microhardness was equal to 8.91 GPa. We have carried out comparison of the values ​​obtained with the microhardness for the other wide bandgap semiconductors - epitaxial GaN layers grown on 6H-SiC and GaP layers grown on GaP:S. The findings are usable for machining process development of β-Ga2O3 single crystal substrates. In particular, silicon carbide and electrocorundum may be recommended for β-Ga2O3 machine processing.

  3. Is osmium diboride an ultra-hard material?

    Science.gov (United States)

    Yang, Jun; Sun, Hong; Chen, Changfeng

    2008-06-11

    We report first-principles calculations of ideal tensile and shear strength for the recently synthesized orthorhombic OsB2 that is a primary example of a new class of ultra-hard materials synthesized by combining small, light, and covalent elements with large, electron-rich transition metals. Our calculations show that the shear strength on the (001) plane is highly anisotropic with a low peak stress of 9.1 GPa in the (001)[010] shear direction but a much higher peak stress of 26.9 GPa in the (001)[100] direction. The strong resistance against (001)[100] shear deformation prevents the indenter from making a deep imprint, giving rise to a high Vickers hardness on the (001) plane, despite the weak shear strength in the (001)[010] shear direction. The calculated peak stress of 26.9 GPa in the (001)[100] shear direction agrees well with the 30 GPa Vickers hardness observed experimentally on the (001) plane in OsB2. However, the weak shear strength (9.1 GPa) in the (001)[010] shear direction severely limits its application as abrasives and cutting tools for ferrous metals as well as scratch-resistance coatings. Our results highlight the importance of understanding atomistic deformation modes under various loading conditions in designing new ultra-hard materials.

  4. Hardness-based plasticity and fracture model for quench-hardenable boron steel (22MnB5)

    OpenAIRE

    Greve, L.; Eller, Tom; Medricky, M; Andres, M.T.

    2013-01-01

    A comprehensive strain hardening and fracture characterization of different grades of boron steel blanks has been performed, providing the foundation for the implementation into the modular material model (MMM) framework developed by Volkswagen Group Research for an explicit crash code. Due to the introduction of hardness-based interpolation rules for the characterized main grades, the hardening and fracture behavior is solely described by the underlying Vickers hardness. In other words, know...

  5. The Theoretical Analysis of Test Result’s Errors for the Roller Type Automobile Brake Tester

    OpenAIRE

    Li, Jun; Zha, Xiaojing; Wu, Dongsheng

    2010-01-01

    International audience; The main testing parameter of the roller brake tester is the braking force. Actually, there are some differences in results even if the same vehicle is tested on the same tester. So it will bring trouble to evaluate the braking performance accurately. Based on force analysis, the mathematical model of the roller opposite force type automobile brake tester is built in this article. And then the factors of influencing braking force value will be analyzed by theoretical c...

  6. Remote use of an Electron Beam Tester (EBT)

    Science.gov (United States)

    Baille, G.; Conquet, F.; Devautour, B.; Gouyon, T.

    1988-10-01

    The first remote use of the TIM3 experimental electron beam tester is described. Thanks to modern lines, it is possible to manage the TESSIE exerciser from any remote terminal. The test pattern memory can be loaded, dumped or modified. The output pattern memory (analysis) can be loaded with circuit truth tables or with the answers given by a golden chip, dumped in a file for future use. Other remote management possibilities are described. Future developments such as transmission of images, simulation and test tool techniques are outlined.

  7. Optical properties and indentation hardness of thin-film acrylated epoxidized oil

    Science.gov (United States)

    Rahman, Mohammad Syuhaimi Ab.; Shaktur, Khaled Mohamed; Mohammad, Rahmah; Zalikha, Wan Aimi; Nawi, Norwimie; Mohd, Ahmad Faiza

    2012-02-01

    Epoxy acrylate has been widely used as optical resin for applications such as cladding, the core of a waveguide, and other photonic devices. In this study, sustainable resin from edible oil was used as an alternative to epoxy acrylate. Structural features and the transmission of planar thin-film resin from an ultraviolet-visible spectroscopy (UV-VIS) spectrometer were investigated upon UV exposure. It was found that high transmission still persists for all samples with and without an UV absorber for exposed and unexposed samples. The film was found to absorb strongly below 400 nm. A change in the cut-off wavelength was observed upon exposure. Thin-film hardness and its dynamic indentation in the load-unload mode with different test forces were evaluated. Vickers hardness and the elastic modulus were determined for unacrylated epoxidized soybean oil (ESO) and acrylated epoxidized soybean oil (AESO). It was found that the AESO has a higher Vickers hardness and elastic modulus than those of unacrylated thin film. The Vickers hardness and elastic modulus were found to increase as the applied test force increased. The refractive index, thickness, and modes present were characterized from a spin-coated planar thin film. The refractive index in the transverse electric mode (TE) and transverse magnetic mode (TM) were determined and compared for unacrylated and acrylated epoxidized oil.

  8. submitter Test strategies for industrial testers for converter controls equipment

    CERN Document Server

    Oleniuk, P; Kasampalis, V; Nisbet, D; Todd, B; Uznański, S

    2017-01-01

    Power converters and their controls electronics are key elements for the operation of the CERN accelerator complex, having a direct impact on its availability. To prevent early-life failures and provide means to verify electronics, a set of industrial testers is used throughout the converters controls electronics' life cycle. The roles of the testers are to validate mass production during the manufacturing phase and to provide means to diagnose and repair failed modules that are brought back from operation. In the converter controls electronics section of the power converters group in the technology department of CERN (TE/EPC/CCE), two main test platforms have been adopted: a PXI platform for mixed analogue-digital functional tests and a JTAG Boundary-Scan platform for digital interconnection and functional tests. Depending on the functionality of the device under test, the appropriate test platforms are chosen. This paper is a follow-up to results presented at the TWEPP 2015 conference, adding the boundary s...

  9. The MSP430-based control system for automatic ELISA tester

    Science.gov (United States)

    Zhao, Xinghua; Zhu, Lianqing; Dong, Mingli; Lin, Ting; Niu, Shouwei

    2006-11-01

    This paper introduces the scheme of a control system for a fully automatic ELISA (Enzyme-linked Immunosorbent Assay) tester. This tester is designed to realize the movement and positioning of the robotic arms and the pipettors and to complete the functions of pumping, reading, washing, incubating and so on. It is based on a MSP430 flash chip, a 16-bit MCU manufactured by TI Co, with very low power consumption and powerful functions. This chip is adopted in all devices of the workstation to run the controlling program, to store involved parameters and data, and to drive stepper motors. To the MCUs, motors, sensors, valves and fans are extended. A personal computer (PC) is employed to communicate with the instrument through an interface board. Relevant hardware circuits are provided. Two programs, one running in PC performs users' operation about assay options and results, the other running in MCU initiates the system and waits for commands to drive the mechanisms, are developed. Through various examinations, this control system is proved to be reliable, efficient and flexible.

  10. Portable tester for determining gas content within a core sample

    Science.gov (United States)

    Garcia, Jr., Fred; Schatzel, Steven J.

    1998-01-01

    A portable tester is provided for reading and displaying the pressure of a gas released from a rock core sample stored within a sealed container and for taking a sample of the released pressurized gas for chemical analysis thereof for subsequent use in a modified direct method test which determines the volume of gas and specific type of gas contained within the core sample. The portable tester includes a pair of low and high range electrical pressure transducers for detecting a gas pressure; a pair of low and high range display units for displaying the pressure of the detected gas- a selector valve connected to the low and high range pressure transducers, a selector knob for selecting gas flow to one of the flow paths; control valve having an inlet connection to the sealed container, and outlets connected to: a sample gas canister, a second outlet port connected to the selector valve means for reading the pressure of the gas from the sealed container to either the low range or high range pressure transducers, and a connection for venting gas contained within the sealed container to the atmosphere. A battery is electrically connected to and supplies the power for operating the unit. The pressure transducers, display units, selector and control valve means and the battery is mounted to and housed within a protective casing for portable transport and use.

  11. Test strategies for industrial testers for converter controls equipment

    Science.gov (United States)

    Oleniuk, P.; Di Cosmo, M.; Kasampalis, V.; Nisbet, D.; Todd, B.; Uznański, S.

    2017-04-01

    Power converters and their controls electronics are key elements for the operation of the CERN accelerator complex, having a direct impact on its availability. To prevent early-life failures and provide means to verify electronics, a set of industrial testers is used throughout the converters controls electronics' life cycle. The roles of the testers are to validate mass production during the manufacturing phase and to provide means to diagnose and repair failed modules that are brought back from operation. In the converter controls electronics section of the power converters group in the technology department of CERN (TE/EPC/CCE), two main test platforms have been adopted: a PXI platform for mixed analogue-digital functional tests and a JTAG Boundary-Scan platform for digital interconnection and functional tests. Depending on the functionality of the device under test, the appropriate test platforms are chosen. This paper is a follow-up to results presented at the TWEPP 2015 conference, adding the boundary scan test platform and the first results from exploitation of the test system. This paper reports on the test software, hardware design and test strategy applied for a number of devices that has resulted in maximizing test coverage and minimizing test design effort.

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

    CERN Document Server

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

    2007-01-01

    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.

  13. Inter-tester and intra-tester reliability of ultrasound imaging measurements of abdominal muscles in adolescents with and without idiopathic scoliosis: a case-controlled study.

    Science.gov (United States)

    Yang, Hoe S; Yoo, Ji W; Lee, Bo A; Choi, Chang K; You, Joshua H

    2014-01-01

    The present study established inter-tester and intra-tester reliabilities of ultrasound imaging and diagnostically differentiated muscle imbalances in lateral abdominal muscle sizes between normal adolescents and adolescents with idiopathic scoliosis (AIS). Fifteen adolescents with AIS were age- and gender-matched with 15 normal adolescents. There was no significant difference between bilateral abdominal muscles in normal adolescents, but there was a significant difference between bilateral abdominal muscles in adolescents with AIS (Ptester and intra-tester reliabilities in normal and AIS adolescents ranged from 0.801-0.984. This novel study shows that using ultrasound imaging to measure lateral abdominal muscle thickness is: (1) highly reliable between and within the testers; and (2) capable of distinguishing between subjects with and without pathological muscle morphology due to AIS.

  14. Intra-tester and inter-tester reliability of post-occlusive reactive hyperaemia measurement at the hallux.

    Science.gov (United States)

    Barwick, Alex; Lanting, Sean; Chuter, Vivienne

    2015-05-01

    Post-occlusive reactive hyperaemia (PORH) is a measurement of the vasodilatory capacity of the microvasculature that is associated with cardiovascular disease, peripheral arterial disease and foot ulceration. The reliability of its measurement in the hallux (great toe) for clinical and research purposes has not been adequately assessed. This study assesses both the intra-tester reliability and inter-tester reliability of four methods of assessing PORH in the hallux. A within-subject repeated measures design was used. Forty-two participants underwent PORH testing using four methods: pressure measurement with photoplethysmography; an automated laser Doppler technique with local heating; an automated laser Doppler technique without local heating; and a manual laser Doppler technique. Participants underwent testing on two occasions with a three to 14 day interval. Laser Doppler measurement with a heating probe was found to be the most reliable method of PORH measurement. The index of the area under the curve pre- and post-occlusion and peak perfusion as a percentage of baseline were the most reliable variables. PORH can be reliably measured using laser Doppler when combined with a heating probe. Further research is required to determine the clinical utility of photoplethysmography in the measurement of PORH. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Hand-Drawn Resistors and a Simple Tester Using a Light-Emitting Diode

    Science.gov (United States)

    Kamata, Masahiro; Abe, Mayumi

    2012-01-01

    A thick line drawn on a sheet of paper with a 6B pencil is electrically conductive and its resistance can be roughly estimated using a simple tester made of a light-emitting diode (LED) and a lithium coin-type cell. Using this hand-drawn resistor and the LED tester, we developed teaching materials that help students to understand how electrical…

  16. LINE X TESTER ANALYSIS IN COMBINING ABILITIES ESTIMATION OF SUNFLOWER OIL CONTENT

    Directory of Open Access Journals (Sweden)

    Ivica Liović

    2012-12-01

    Full Text Available Results of line x tester analysis for 15 sunflower genotypes of the Agricultural Institute Osijek are presented in this paper. Three A lines (cms and three Rf testers with different oil content level (low, medium, high in all combinations (nine crosses were crossed in 2010. In 2011, the lines, testers and their crosses were sown in field trials at two locations (Karanac and Osijek. The oil content was determined after harvesting, whereas line x tester analysis was conducted based on the obtained results. Variance of lines and testers, which refers to the general combining ability (GCA was much higher than the variance of line x tester, related to specific combining ability (SCA. It showed on dominant role of the additive component of genetic variance in the inheritance of oil content. Statistically significant differences were not determined between the GCA and SCA effects. The highest values of GCA for oil content had line 2 (medium oil content and tester 6 (high oil content at both locations. The largest contribution for oil content had lines (57.81 and 51.28 % followed by testers (28.88 and 26.27 % and the lowest accounts for interaction (13.31 and 22.45 % at both locations (Karanac and Osijek.

  17. 16 CFR Figure 3 to Subpart A of... - Flooring Radiant Tester Schematic Side Elevation

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Flooring Radiant Tester Schematic Side Elevation 3 Figure 3 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION.... 1209, Subpt. A, Fig. 3 Figure 3 to Subpart A of Part 1209—Flooring Radiant Tester Schematic Side...

  18. Hardness and dielectric characteristics of flux grown terbium aluminate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, K.K.; Kotru, P.N. [Jammu Univ. (India). Dept. of Physics; Tandon, R.P. [National Physical Laboratory, New Delhi (India); Wanklyn, B.M. [Clarendon Laboratory, University of Oxford, Oxford (United Kingdom)

    1999-01-29

    Results of indentation induced Vickers hardness testing and dielectric studies conducted on flux-grown terbium aluminate crystals are presented. It is shown that the Vickers hardness value (H{sub v}) is independent of indentation time, but depends on the applied load. Applying the concept of Hays and Kendall, the load independent values are estimated for (110) and (001) planes. Differential behaviour in the crack formation of two different planes (110) and (001) is observed, while (001) plane develops Palmqvist cracks in the whole load range of 10-100 g, (110) plane shows a transition from Palmqvist to median cracks at 70 g. The fracture toughness, brittleness index and yield strength are determined for both the planes. The hardness anisotropy is reported. The dielectric constant, dielectric loss and conductivity are shown to be dependent on temperature and frequency of the applied a.c. field. The dielectric constant versus temperature shows a transition peak at 230 C, which remains independent of the frequency of the applied a.c. field in the range 1 kHz-13 MHz. (orig.) 36 refs.

  19. The Automated Bicron Tester: Automated electronic instrument diagnostic, testing, and alignment system with records generation

    Energy Technology Data Exchange (ETDEWEB)

    Rao, G.S.; Maddox, S.R.; Turner, G.W.; Vandermolen, R.I.

    1995-11-01

    The Bicron Surveyor MX is a portable radiation monitoring instrument used by the Office of Radiation Protection at Oak Ridge National Laboratory. This instrument must be calibrated in order to assure reliable operation. A manual calibration procedure was developed, but it was time consuming and repetitive. Therefore, an automated tester station that would allow the technicians to calibrate the instruments faster and more reliably was developed. With the automated tester station, calibration records and accountability could be generated and maintained automatically. This allows the technicians to concentrate on repairing defective units. The Automated Bicron Tester consists of an operator interface, an analog board, and a digital controller board. The panel is the user interface that allows the technician to communicate with the tester. The analog board has an analog-to-digital converter (ADC) that converts the signals from the instrument into digital data that the tester can manipulate. The digital controller board contains the circuitry to perform the test and to communicate the results to the host personal computer (PC). The tester station is connected to the unit under test through a special test harness that attaches to a header on the Bicron. The tester sends pulse trains to the Bicron and measures the resulting meter output. This is done to determine if the unit is functioning properly. The testers are connected to the host PC through an RS-485 serial line. The host PC polls all the tester stations that are connected to it and collects data from those that have completed a calibration. It logs these data and stores the record in a format ready for export to the Maintenance, Accountability, Jobs, and Inventory Control (MAJIC) database. It also prints a report. The programs for the Automated Bicron Tester and the host are written in the C language.

  20. DESIGN AND FABRICATION OF A LOW SPEED IMPACT TESTER

    Directory of Open Access Journals (Sweden)

    M. Navarrete

    2004-12-01

    Full Text Available The impact response of sandwich panels with an improved structure to increase their impact resistance isinvestigated. In order to compare the impact performance of sandwich structures, a specific and instrumenteddrop-weight impact tester was designed and developed. The experimental part of this work is an evaluation oncomposite sandwich panels behavior used in the manufacturing of the UNAM Electrobús chassis. Two differentsandwich structures are analyzed: the first type is a structure composed by a glass fiber-polyester matrix compositefacesheets and a polyethylene honeycomb core. The second one consists of facesheets made from a glass fiberepoxymatrix composite laminate and core formed by internal phenolic honeycomb structure. The first structurewas specifically designed to improve crashworthiness for transport applications. The main results of this study areevaluated from the absorbed energy performance of the sandwich structures subjected to a single impact, and thedevelopment of useful criteria for materials selection.

  1. A portable fracture toughness tester for biological materials

    Science.gov (United States)

    Darvell, B. W.; Lee, P. K. D.; Yuen, T. D. B.; Lucas, P. W.

    1996-06-01

    A portable mechanical tester is described which is both lightweight and cheap to produce. The machine is simple and convenient to operate and requires only a minimum of personnel training. It can be used to measure the fundamental mechanical properties of pliant solids, particularly toughness (in the sense of `work of fracture') using either scissors or wedge tests. This is achieved through a novel hardware integration technique. The circuits are described. The use of the machine does not require a chart recorder but it can be linked to a personal computer, either to show force - displacement relationships or for data storage. The design allows the use of any relatively `soft' mechanical test, i.e. tests in which the deformability of the frame of the machine and its load cell do not introduce significant errors into the results. Examples of its use in measuring the toughness of biomaterials by scissors (paper, wood) and wedges (mung bean starch gels) are given.

  2. Heat flux measurement in SSME turbine blade tester

    Science.gov (United States)

    Liebert, Curt H.

    1990-01-01

    Surface heat flux values were measured in the turbine blade thermal cycling tester located at NASA-Marshall. This is the first time heat flux has been measured in a space shuttle main engine turbopump environment. Plots of transient and quasi-steady state heat flux data over a range of about 0 to 15 MW/sq m are presented. Data were obtained with a miniature heat flux gage device developed at NASA-Lewis. The results from these tests are being incorporated into turbine design models. Also, these gages are being considered for airfoil surface heat flux measurement on turbine vanes mounted in SSME turbopump test bed engine nozzles at Marshall. Heat flux effects that might be observed on degraded vanes are discussed.

  3. A multicommutated tester of bioreactors for flow analysis.

    Science.gov (United States)

    Pokrzywnicka, Marta; Kamiński, Jacek; Michalec, Michał; Koncki, Robert; Tymecki, Łukasz

    2016-11-01

    Enzymes are often used in the modern analytical procedures allowing selective recognition and conversion of target analytes into easily detected products. In flow analysis systems, enzymes are predominantly applied in the immobilized forms as flow-through bioreactors. In this research the multicommutated flow analysis (MCFA) system for evaluation and comparison of analytical parameters of bioreactors has been developed. The MCFA manifold allows simultaneous testing up to four bioreactors, but if necessary their number can be easily increased. The system allows comparison of several parameters of tested bioreactors including activity, repeatability, reproducibility, operational and storage stability. The performance of developed bioreactor tester is presented using urea-urease model system based on plastic open-tubular bioreactor with covalently immobilized enzyme. Product of enzymatic reaction is detected using two different chemical methods and by dedicated optoelectronic ammonium detectors. Moreover, the utility of developed MCFA manifold for evaluation of other enzyme bioreactors is demonstrated. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Initial Development of an Electronic Testis Rigidity Tester

    Directory of Open Access Journals (Sweden)

    Petros Mirilas

    2011-01-01

    Full Text Available We aimed to develop our previously presented mechanical device, the Testis Rigidity Tester (TRT, into an electronic system (Electronic Testis Rigidity Tester, ETRT by applying tactile imaging, which has been used successfully with other solid organs. A measuring device, located at the front end of the ETRT incorporates a tactile sensor comprising an array of microsensors. By application of a predetermined deformation of 2 mm, increased pressure alters linearly the resistance of each microsensor, producing changes of voltage. These signals were amplified, filtered, and digitized, and then processed by an electronic collector system, which presented them as a color-filled contour plot of the area of the testis coming into contact with the sensor. Testis models of different rigidity served for initial evaluation of ETRT; their evacuated central spaces contained different, increasing glue masses. An independent method of rigidity measurement, using an electric weight scale and a micrometer, showed that the more the glue injected, the greater the force needed for a 2-mm deformation. In a preliminary test, a single sensor connected to a multimeter showed similar force measurement for the same deformation in these phantoms. For each of the testis models compressed in the same manner, the ETRT system offered a map of pressures, represented by a color scale within the contour plot of the contact area with the sensor. ETRT found certain differences in rigidity between models that had escaped detection by a blind observer. ETRT is easy to use and provides a color-coded “insight“ of the testis internal structure. After experimental testing, it could be valuable in intraoperative evaluation of testes, so that the surgeon can decide about orchectomy or orcheopexy.

  5. Effect of Preoperative Occlusal Matrices on the Vickers Microhardness of Composite Disks Polymerized with QTH and LED Lamps.

    Science.gov (United States)

    Castillo-Oyagüe, Raquel; Milward, Paul J; Martín-Cerrato, Alicia; Lynch, Christopher D

    2015-01-01

    This study aimed to assess the reliability of the preoperative occlusal matrix technique in terms of the surface Vickers microhardness (VMH) of the underlying composite restorative material. Two hundred microhybrid composite cylinders were built up and light-cured in a single-layer step, forming two experimental groups (N = 100) according to their heights (1.5 mm/2 mm). Each group was divided into five subgroups (N = 20) depending on the matrix thickness (no matrix/0.5 mm/1 mm/2 mm/3 mm). Half the specimens per subgroup (N = 10) were randomly polymerized with a quartz-tungsten-halogen (QTH) light-curing unit (LCU). The remaining half were cured using a light-emitting diode lamp. The top and bottom samples' sides were tested for VMH at 1 hour and 24 hours post-curing using a universal VMH machine. A multiple analysis of variance with repeated measurements for the "surface" factor and the Student-Newman-Keuls test were run (α = 0.05). Bottom/top microhardness ratios were compared with the empirically accepted limit (0.8). Surface topography was analyzed under a scanning electron microscope. The thinnest matrices provided the significantly best VMH values. LCU, disc height, and time also contributed to VMH. At 24 hours, 2-mm high discs polymerized with QTH resulted in inadequate microhardness ratios when 1-mm thick to 3-mm thick matrices were used. The thinnest matrices are the most recommendable ones. The esthetics and occlusal reproducibility achieved with customized occlusal matrices fabricated before cavity preparation have been widely demonstrated. However, their effect on the physical properties of the restorations deserves further investigation. Although more studies are necessary, the thinnest matrices seem to be the most suitable to preserve the composite surface VMH and the curing depth. © 2015 Wiley Periodicals, Inc.

  6. Microindentation Hardness of Protein Crystals under Controlled Relative Humidity

    Directory of Open Access Journals (Sweden)

    Takeharu Kishi

    2017-11-01

    Full Text Available Vickers microindentation hardness of protein crystals was investigated on the (110 habit plane of tetragonal hen egg-white lysozyme crystals containing intracrystalline water at controlled relative humidity. The time evolution of the hardness of the crystals exposed to air with different humidities exhibits three stages such as the incubation, transition, and saturation stages. The hardness in the incubation stage keeps a constant value of 16 MPa, which is independent of the humidity. The incubation hardness can correspond to the intrinsic one in the wet condition. The increase of the hardness in the transition and saturation stages is well fitted with the single exponential curve, and is correlated with the reduction of water content in the crystal by the evaporation. The saturated maximum hardness also strongly depends on the water content equilibrated with the humidity. The slip traces corresponding to the (11 ̅0[110] slip system around the indentation marks are observed in not only incubation but also saturation stages. It is suggested that the plastic deformation in protein crystals by the indentation can be attributed to dislocation multiplication and motion inducing the slip. The indentation hardness in protein crystals is discussed in light of dislocation mechanism with Peierls stress and intracrystalline water.

  7. Intra and inter-tester reliability of the tuck jump assessment.

    Science.gov (United States)

    Herrington, Lee; Myer, Gregory D; Munro, Allan

    2013-08-01

    To assess the inter-tester and intra-tester reliability of the tuck jump test. Repeated measures. University Human Performance laboratory. Five male and 5 female athletes undertook the Tuck jump test which was then assessed by two independent assessors. Score from the video assessment of the tuck jump test by two independent assessors on two separate occasions. Average percentage of exact agreement (PEA) between the two testers across all scoring criteria for all subjects was 93% (range 80-100%). Both testers were in absolute 100% agreement in 5 out of 10 subjects for all of the scoring criteria. The kappa measure of agreement was k = 0.88 which is very good/excellent. The intra-tester PEA ranged 87.2%-100%, with kappa values of k = 0.86-1.0. The study showed very good-excellent intra-tester and inter-tester reliability for both examiners when comparing their individual scores of the tuck jump test across two analysis sessions. These findings indicate that the proposed tuck jump assessment is reliable to identify abnormal landing mechanics. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Tester Board for testing mass-produced SMB modules for CMS Preshower

    CERN Document Server

    Velikzhanin, Yu S; Hsiung, Y B; Lee, Y J; Shiu, J G; Sun, C D; Wang, Y Z

    2007-01-01

    We have developed a Tester Board to test the electrical characteristics of the System Motherboard (SMB) for the CMS Preshower detector at CERN. The board is designed to test input resistances, output resistances, connections, interconnections and possible short- circuits of a module having up to 640 connector pins. The Tester Board is general-purpose in nature: it could be used to test any electronic module or cable by using dedicated cable sets. The module can detect a variety of problems not detected by either functional tests or the "flying probes" technique. The design, algorithms and results of using the Tester Board during mass production of CMS Preshower SMBs are presented.

  9. The hardness of synthetic products obtained from cooled and crystallized basaltic melts (in Romanian

    Directory of Open Access Journals (Sweden)

    Daniela Ogrean

    2001-04-01

    Full Text Available The Hardness of Synthetic Products Obtained from Cooled and Crystallized Basaltic Melts. Hardness is one of the main properties of the products obtained from cooled and crystallized basaltic melts under a controlled thermal regime. It influences the abrasion tear resistance of the resulted material. The microhardness measurements on the samples (bricks, boards, gutters, armour plates, tubes indicated Vickers hardness value between 757–926 for the materials obtained from Şanovita basalts (Timiş district and between 539–958 respectively, in case of the Racoş basalts (Braşov district. There is a certain variation of the hardness within the same sample, in various measurement points, within the theoretical limits of the hardnesses of the pyroxenes and that of the spinels.

  10. Reliability of knee joint range of motion and circumference measurements after total knee arthroplasty: does tester experience matter?

    DEFF Research Database (Denmark)

    Jakobsen, Thomas Linding; Christensen, Malene; Christensen, Stine Sommer

    2010-01-01

    BACKGROUND AND PURPOSE: Two of the most utilized outcome measures to assess knee joint range of motion (ROM) and intra-articular effusion are goniometry and circumference, respectively. Neither goniometry nor circumference of the knee joint have been examined for both intra-tester and inter......-tester in patients with total knee arthroplasty (TKA). The purpose of this study was to determine the intra-tester and inter-tester reliability of active and passive knee joint ROM and circumference in patients with TKA when administered by physiotherapists (testers) with different clinical experience. METHOD......: The design was an intra-tester, inter-tester and intra-day reliability study. Nineteen outpatients (10 females) having received a TKA were examined by an inexperienced and an experienced physiotherapist. Following a standardized protocol, active and passive knee joint ROM and circumference measurements were...

  11. Pulse shaping techniques for a high-g shock tester based on collision principle.

    Science.gov (United States)

    Duan, Zhengyong; Tang, Chuansheng; Li, Yang; Han, Junliang; Wu, Guoxiong

    2016-09-01

    Pulse shaping techniques are discussed in this paper for the practicability of a developed high-g shock tester. The tester is based on collision principle where there is a one-level velocity amplifier. A theoretical and experimental study of pulse shaping techniques is presented. A model was built and theoretical formulae were deduced for the shock peak acceleration and its duration. Then theoretical analysis and some experiments were conducted. The test results verify the validity of theoretical model and show that the shock tester can generate the expected high-g shock pulses by integrated usage of different impact velocities and pulse shapers made from different materials. This is important in practical applications where the items under test can be shown to excite specific resonances at predetermined acceleration levels using the shock tester.

  12. Instruction manual for installation, operation, and maintenance of the Q-250 LLNL filter-life tester

    Energy Technology Data Exchange (ETDEWEB)

    Foote, K.L.; da Roza, R.A.

    1990-12-21

    This manual describes the installation, operation, and maintenance of the LLNL, filter-life tester Q-250. This apparatus is designed to determined the gas life of a variety of chemical filters, such as M10-A1, M11, M13-A2, C2, and similar filters. The LLNL filter-life tester can generate isopropymethylphosphonoflouridate (GB) or dimethyl methylphosphonate (DMMP) vapors in air at flow rates of up to 50 1pm. These filters and their specifications are listed in Appendix A. CAUTION: Personnel performing operations with this tester must be completely familiar with the contents of this manual, knowledgeable in system operation, and knowledgeable of materials used in operation of the LLNL filter-life tester.

  13. Evaluation of disintegration properties of orally rapidly disintegrating tablets using a novel disintegration tester.

    Science.gov (United States)

    Kondo, Keita; Niwa, Toshiyuki; Danjo, Kazumi

    2012-01-01

    This report describes a new disintegration tester that can determine not only the disintegration time of orally rapidly disintegrating tablets (ODT), but also the disintegration behavior and mechanism. Using the tester, the disintegration properties of the tablets prepared in a previous study were examined. The purpose of this study is to confirm the utility of the tester as an instrument for evaluating the disintegration properties of ODT and determine relations among time, behavior and mechanism of the disintegration. Results demonstrated that in vitro disintegration time in the tester is similar to that in the commercial disintegration tester for ODT and is highly correlated with oral disintegration time. Observations of disintegration process revealed that a difference in disintegration behavior between tablets compressed at 50-75 MPa and 100 MPa; the disintegration behavior of the tablets were designated immediate disintegrating type and gradual disintegrating type, respectively. The dynamic swelling profile and water absorption profile indicated that the disintegration mechanism of the tablets involved wicking action induced by swelling of the disintegrant; the disintegration time was closely related to the initial rates of swelling and water absorption. Furthermore, the mechanism of water absorption of tablets compressed at 50-75 MPa and 100 MPa shows anomalous diffusion and case-II transport, respectively. The shift in this mechanism is consistent with differences in disintegration time and behavior between the tablets. These findings suggest that information on disintegration properties obtained by our tester is useful for understanding of disintegration phenomena of ODT.

  14. On the interpretation of the indentation size effect (ISE) through gradient theory for Vickers and Berkovich indenters

    Science.gov (United States)

    Kampouris, Asterios K.; Konstantinidis, Avraam A.

    2016-12-01

    The so-called indentation size effect (ISE) observed mainly in nanoindentation measurements with prismatic tips, is theoretically modeled in this article with the use of gradient theory. It is shown that the ISE, i.e. the dependence of the calculated hardness value on the indentation depth, is rather an artifact of the geometry of the tip used, than a phenomenon related to the material tested. The model predictions are compared with nanoindentation measurements of Al specimens.

  15. Etiske utfordringer med non-invasive prenatale tester (NIPT

    Directory of Open Access Journals (Sweden)

    Bjørn Hofmann

    2014-05-01

    Full Text Available Analyser av cellefritt DNA fra foster i gravide kvinners blod gir nye muligheter innen fosterdiagnostikk: Testene er bedre enn eksisterende tester, de reduserer risikoen og er billigere. Flere land har tatt i bruk disse testene, og Helsedirektoratet i Norge har mottatt søknad om å ta i bruk en test som erstatter tidlig ultralyd og blodprøver. Likevel nøler norske myndigheter. Hvorfor gjør de det? Ett av svarene er at non-invasive prenatale tester fører med seg en rekke faglige og moralske spørsmål og gir flere grunnleggende etiske utfordringer. Denne artikkelen gjennomgår et bredt knippe av de utfordringene som NIPT reiser. Hensikten er å synliggjøre hvorfor NIPT påkaller etisk refleksjon og å bidra til en åpen debatt og en transparent beslutningsprosess. Artikkelen identifiserer fem sentrale og konkrete spørsmål for vurderingen av NIPT.Nøkkelord: non-invasiv prenatal diagnostikk, testing, fravalg, foster, blodprøve, ekspressivisme, statsliberalt dilemma, dilemma, abort, retten til ikke å viteEnglish summary: Ethical challenges with non-invasive prenatal tests (NIPTNon-invasive prenatal testing (NIPT performed with the use of massively parallel sequencing of cell-free DNA (cfDNA testing in maternal plasma gives extended possibilities in prenatal screening. The tests are claimed to be better than existing alternative tests, they reduce the risk, and it is claimed they are cheaper. They have been used in several countries since 2012, and the University Hospital of North Norway has applied to the Directorate of Health to replace first trimester ultrasound and plasma screening with NIPT. The Directorate of Health is reluctant to reply. Why is this? One of the answers may be that NIPT raises a series of professional and moral questions, and poses profound ethical challenges. This article reviews a series of the challenges with NIPT. The aim is to highlight why NIPT calls for ethical reflection and to contribute to an open debate

  16. Hardness-based plasticity and fracture model for quench-hardenable boron steel (22MnB5)

    Energy Technology Data Exchange (ETDEWEB)

    Greve, L., E-mail: lars.greve@volkswagen.de; Medricky, M., E-mail: miloslav.medricky@volkswagen.de; Andres, M., E-mail: miloslav.medricky@volkswagen.de [Volkswagen AG, Letter Box 1777, Wolfsburg, 38436 (Germany); Eller, T. K., E-mail: tom.karl.eller@volkswagen.de [Volkswagen AG, Letter Box 1777, Wolfsburg, 38436, Germany, and University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)

    2013-12-16

    A comprehensive strain hardening and fracture characterization of different grades of boron steel blanks has been performed, providing the foundation for the implementation into the modular material model (MMM) framework developed by Volkswagen Group Research for an explicit crash code. Due to the introduction of hardness-based interpolation rules for the characterized main grades, the hardening and fracture behavior is solely described by the underlying Vickers hardness. In other words, knowledge of the hardness distribution within a hot-formed component is enough to set up the newly developed computational model. The hardness distribution can be easily introduced via an experimentally measured hardness curve or via hardness mapping from a corresponding hot-forming simulation. For industrial application using rather coarse and computationally inexpensive shell element meshes, the user material model has been extended by a necking/post-necking model with reduced mesh-dependency as an additional failure mode. The present paper mainly addresses the necking/post-necking model.

  17. Hardness-based plasticity and fracture model for quench-hardenable boron steel (22MnB5)

    Science.gov (United States)

    Greve, L.; Eller, T. K.; Medricky, M.; Andres, M.

    2013-12-01

    A comprehensive strain hardening and fracture characterization of different grades of boron steel blanks has been performed, providing the foundation for the implementation into the modular material model (MMM) framework developed by Volkswagen Group Research for an explicit crash code. Due to the introduction of hardness-based interpolation rules for the characterized main grades, the hardening and fracture behavior is solely described by the underlying Vickers hardness. In other words, knowledge of the hardness distribution within a hot-formed component is enough to set up the newly developed computational model. The hardness distribution can be easily introduced via an experimentally measured hardness curve or via hardness mapping from a corresponding hot-forming simulation. For industrial application using rather coarse and computationally inexpensive shell element meshes, the user material model has been extended by a necking/post-necking model with reduced mesh-dependency as an additional failure mode. The present paper mainly addresses the necking/post-necking model.

  18. Analysis of surface hardness of artificially aged resin composites

    Directory of Open Access Journals (Sweden)

    Denise Cremonezzi Tornavoi

    2012-02-01

    Full Text Available This study evaluated the effect of artificially accelerated aging (AAA on the surface hardness of eight composite resins: Filtek Z250, Filtek Supreme, 4 Seasons, Herculite, P60, Tetric Ceram, Charisma, and Filtek Z100. Sixteen specimens were made from the test piece of each material, using an 8.0 × 2.0 mm teflon matrix. After 24 hours, eight specimens from each material were submitted to three surface hardness readings using a Shimadzu Microhardness Tester for 5 seconds at a load of 50 gf. The other eight specimens remained in the artificially accelerated aging machine for 382 hours and were submitted to the same surface hardness analysis. The means of each test specimen were submitted to the Kolmogorov-Smirnov test (p > 0.05, ANOVA and Tukey test (p < 0.05. With regard to hardness (F = 86.74, p < 0.0001 the analysis showed significant differences among the resin composite brands. But aging did not influence the hardness of any of the resin composites (F = 0.39, p = 0.53. In this study, there was interaction between the resin composite brand and the aging factors (F = 4.51, p < 0.0002. It was concluded that notwithstanding the type of resin, AAA did not influence surface hardness. However, with regard to hardness there was a significant difference among the resin brands.

  19. The reliability of the newly developed bending tester for the measurement of flexural rigidity of textile materials

    Science.gov (United States)

    Haji Musa, A. Binti; Malengier, B.; Van Langenhove, L.; Stevens, C.

    2017-10-01

    A new automated bending tester was developed in Ghent University, Belgium to reduce the human interference in the bending measurement. This paper reports the investigations made on the tester in order to confirm the reliability of its measurement. For that, 11 types of fabrics with different construction parameters were tested for their bending length and flexural rigidity using the new bending tester and the results were compared with that of the standard or manual bending tester, which were conducted in accordance with BS 3356:1990 standard method. Statistical analysis confirms that both measurements are strongly correlated with Pearson’s R≥ 0.90 for all the measurements made. It means that the results from the new automated tester show good correlations with the standard measurement. Nevertheless, this prototype version of the new tester still needs to be adjusted to optimise the functionality of it and further investigations should be done to justify the robustness of the results.

  20. Evaluation of hardness and wear resistance of interim restorative materials.

    Science.gov (United States)

    Savabi, Omid; Nejatidanesh, Farahnaz; Fathi, Mohamad Hossein; Navabi, Amir Arsalan; Savabi, Ghazal

    2013-03-01

    The interim restorative materials should have certain mechanical properties to withstand in oral cavity. The aim of this study was to evaluate the hardness and wear resistance of interim restorative materials. Fifteen identical rectangular shape specimens with dimensions of 2 mm × 10 mm × 30 mm were made from 7 interim materials (TempSpan, Protemp 3 Garant, Revotek, Unifast LC, Tempron, Duralay, and Acropars). The Vickers hardness and abrasive wear of specimens were tested in dry conditions and after 1 week storage in artificial saliva. The depth of wear was measured using surface roughness inspection device. Data were subjected to Kruskal-Wallis and Mann-Whitney tests. The Pearson correlation coefficient was used to determine the relationship between hardness and wear (α =0.05). TempSpan had the highest hardness. The wear resistance of TempSpan (in dry condition) and Revotek (after conditioning in artificial saliva) was significantly higher (P materials (P = 0.281, r = -0.31). Hardness and wear resistance of interim resins are material related rather than category specified.

  1. Effect of Crystallisation Degree on Hardness of Basaltic Glass-Ceramics

    DEFF Research Database (Denmark)

    Jensen, Martin; Smedskjær, Morten Mattrup; Yue, Yuanzheng

    The dependence of hardness of basaltic glass-ceramics on their crystallisation degree has been explored by means of differential scanning calorimetry, optical microscopy, X-ray diffraction, and Vickers indentation. Different degrees of crystallisation in the basaltic glasses have been obtained...... by varying the temperature of heat treatment. The change of the relative degree of crystallisation with the heat treatment temperature can be described by an empirical model established in this work. The predominant crystalline phase in the glass has been identified as the pyroxene augite. The hardness...... of the augite crystals is in the range of the hardness of a similar pyroxene, i.e., a pure diopside crystal. The hardness of diopside has been both measured and calculated. The calculation has been done by considering the strength of each individual bond and the amount of bonds per volume, i.e., by using first...

  2. Comparing Variability of Parameters between Roller Bed Brakes Testers and Dynamometric Platform of Ministry Of Transport Facilities

    OpenAIRE

    Senabre C; Valero S; Velasco E

    2015-01-01

    This study gives a comparison between which parameters may vary when braking on two different Ministry of Transport (MOT) brake testers, such as roller bed brake tester and dynamometric platform. A comparative study between both types of brake testers have been carried out by the mechanical engineering staffs at the mechanical laboratory at the Miguel Hernández University in Elche to determinate which parameters can vary the result of the test.

  3. Comparing Variability of Parameters between Roller Bed Brakes Testers and Dynamometric Platform of Ministry Of Transport Facilities

    Directory of Open Access Journals (Sweden)

    Senabre C

    2015-01-01

    Full Text Available This study gives a comparison between which parameters may vary when braking on two different Ministry of Transport (MOT brake testers, such as roller bed brake tester and dynamometric platform. A comparative study between both types of brake testers have been carried out by the mechanical engineering staffs at the mechanical laboratory at the Miguel Hernández University in Elche to determinate which parameters can vary the result of the test.

  4. Does tester experience influence the reliability with which 3D gait kinematics are collected in healthy adults?

    Science.gov (United States)

    Leigh, Ryan J; Pohl, Michael B; Ferber, Reed

    2014-05-01

    To determine whether tester experience influences the reliability of three-dimensional gait collections. Reliability study. Ten healthy subjects visited a university gait laboratory on two separate days and underwent a walking gait analysis. During each visit, kinematic data were collected by a biomechanist with 8 years of 3D gait analysis experience (EXP) and a physical therapist with no previous 3D gait analysis experience (NOV). Joint kinematic angles were calculated using either a functional or predictive joint identification method. Within-tester and between-tester measures of reliability were determined by calculating the root mean square error (RMS) and coefficient of multiple correlations (CMC). Within-tester RMS and CMC values were not significantly different (P > 0.05) between the EXP and NOV testers using either a functional or predictive joint approach. Within-tester CMC values exceeded 0.90 for both testers across all kinematic variables. Between-tester CMC reliability values were greater than 0.85 for all variables measured. Following basic training, a physiotherapy clinician with no previous 3D gait experience is as reliable as an experienced gait biomechanist with respect to marker placement accuracy. In addition, reliability comparisons between an experienced and novice tester appear independent of the joint identification method chosen. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Forces applied with a hoof tester to cadaver feet vary widely between users.

    Science.gov (United States)

    Arndt, J L; Pfau, T; Day, P; Pardoe, C; Bolt, D M; Weller, R

    2013-02-16

    Hoof testers are commonly used in equine practice. In this study, we determined the intraoperator and interoperator reliability of force application with hoof testers for different groups: experienced veterinarians, novices and farriers. For this purpose, we have developed and validated an instrumented hoof tester. Forces varied significantly between the different regions of the foot for experienced operators applying the highest forces to the heels, then the frog, then the toe, and the lowest forces to the quarters. Novices applied significantly more force to the toe versus the frog. Intraoperator reliability varied significantly between regions and operators. Novices had the narrowest width of limits of agreement for the frog and heel, but the widest for the toe and the quarters, whereas farriers had the narrowest width of agreement for the toe and quarter. Force application differed significantly between groups for the frog and heel regions, but not the toe and quarters. Veterinarians applied higher forces to the frog compared with farriers and novices, and higher forces to the heel compared with novices. This study showed that hoof tester forces vary widely within and between operators, and standardisation of hoof tester use is needed to make this diagnostic test more reliable.

  6. Evaluating the importance of the convex hull in solving the Euclidean version of the traveling salesperson problem: reply to Lee and Vickers (2000).

    Science.gov (United States)

    MacGregor, J N; Ormerod, T C

    2000-10-01

    Lee and Vickers (2000) suggest that the results of MacGregor and Ormerod (1996), showing that the response uncertainty to traveling salesperson problems (TSPs) increases with increasing numbers of nonboundary points, may have resulted as an artifact of constraints imposed in the construction of stimuli. The fact that similar patterns of results have been obtained for our "constrained" stimuli, for a stimulus constructed under different constraints, for 13 randomly generated stimuli, and for random and patterned 48-point problems provides empirical evidence that the results are not artifactual. Lee and Vickers further suggest that, even if not artifactual, the results are in principle limited to arrays of fewer than 50 points and that, beyond this, the total number of points and number of nonboundary points are "diagnostically equivalent." This claim seems to us incorrect, since arrays of any size can be constructed that will permit experimental tests of whether problem difficulty is influenced by the number of nonboundary points, or the total number of points, or both. We present a reanalysis of our original data using hierarchical regression analysis which indicates that both factors may influence problem complexity.

  7. System architecture of a gallium arsenide one-gigahertz digital IC tester

    Science.gov (United States)

    Fouts, Douglas J.; Johnson, John M.; Butner, Steven E.; Long, Stephen I.

    1987-01-01

    The design for a 1-GHz digital integrated circuit tester for the evaluation of custom GaAs chips and subsystems is discussed. Technology-related problems affecting the design of a GaAs computer are discussed, with emphasis on the problems introduced by long printed-circuit-board interconnect. High-speed interface modules provide a link between the low-speed microprocessor and the chip under test. Memory-multiplexer and memory-shift register architectures for the storage of test vectors are described in addition to an architecture for local data storage consisting of a long chain of GaAs shift registers. The tester is constructed around a VME system card cage and backplane, and very little high-speed interconnect exists between boards. The tester has a three part self-test consisting of a CPU board confidence test, a main memory confidence test, and a high-speed interface module functional test.

  8. Design of generated axial force measurement tester for tripod constant velocity joints under shudder condition

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kwang Hee; Lee, Deuk Won; Chung, Jin Ho; Lee, Chul Hee [Inha University, Incheon (Korea, Republic of); Cho, Won Oh [ChangAm LS, Asan (Korea, Republic of)

    2014-10-15

    Generated axial force (GAF) induced by internal friction in a tripod constant velocity (CV) joint causes shudder, which is related to lateral vibration in a vehicle. GAF is produced by tripod dynamics in the CV joint, and its magnitude is related to an applied torque and articulation angle. GAF provides periodic frictional force, owing to its kinematics, and causes take-off shudder that occurs when a vehicle abruptly accelerates from a stop position. Therefore, accurately estimating the GAF in a CV joint is necessary. A non-rotating type GAF measurement tester is developed to measure GAF more accurately, considering the shudder condition. Results of GAF measurements are compared with those obtained using an existing rotating-type tester. The developed tester provides linear results regardless of test conditions; thus, it can be used to estimate the magnitude of GAF and evaluate the friction performance of grease.

  9. Effect of acidic food and drinks on surface hardness of enamel, dentine, and tooth-coloured filling materials.

    Science.gov (United States)

    Wongkhantee, S; Patanapiradej, V; Maneenut, C; Tantbirojn, D

    2006-03-01

    The purpose of this study was to determine the effect of acidic food and drinks (Cola soft drink, drinking yogurt, orange juice, sports drink, Tom-yum soup) on surface hardness of various substrates (enamel, dentine, universal composite, microfilled composite, conventional glass ionomer, resin-modified glass ionomer, polyacid-modified resin composite). Specimens (n = 10) were alternately immersed, 5 s each, in food or drinks and in artificial saliva for 10 cycles. Baseline and post-immersion Vickers hardness were compared using paired t-test. The difference in hardness between the groups was analysed with one-way ANOVA followed by a least significant different (LSD) test. Cola soft drink significantly reduced surface hardness of enamel, dentine, microfilled composite, and resin modified glass ionomer (p Tom-yum soup did not reduce surface hardness of any substrate. This in vitro study confirms the erosive potential of certain acidic food and drinks that public should be aware of.

  10. Inter-tester reliability of non-invasive technique for measurement of innominate motion.

    Science.gov (United States)

    Adhia, Divya Bharatkumar; Bussey, Melanie D; Mani, Ramakrishnan; Jayakaran, Prasath; Aldabe, Daniela; Milosavljevic, Stephan

    2012-02-01

    Although the complex anatomical orientation and position of the sacroiliac joints (SIJ) has rendered their 3D kinematic evaluation difficult, recent techniques of palpation-digitization of pelvic landmarks using electromagnetic tracking device have been able to accurately and non-invasively quantify the subtle SIJ kinematics. While this technique demonstrates radiographic validity and high test-retest reliability, it is yet to be assessed with regards to inter-tester and trial-to-trial reliability. A single-group repeated measure design using 4 testers was conducted to evaluate the inter-tester and trial-to-trial reliability of palpation-digitization technique for innominate vector length measurements using the Polhemus electromagnetic tracking device. Fourteen young, healthy adults between the ages of 18-40 years participated in the study. The innominate vector length was calculated from 3D co-ordinates of palpated and digitized pelvic landmarks in two test positions of hip. A sensitivity analysis was conducted to determine how palpation-digitization errors for pelvic landmarks impacts on innominate angle calculation. Reliability indexes of Intraclass correlation coefficient (ICC) (≥0.97) and Standard error of measurement (SEM) (≤2.02 mm) demonstrated very high inter-tester and trial-to-trial reliability and accuracy of palpation-digitization technique for innominate vector length measurements, irrespective of the two test positions. A higher consistency of measurements was obtained within-testers as compared to between testers, and sensitivity analysis demonstrated a negligible influence of palpation-digitization errors on the innominate angle measurements. The results support clinical and research utility of this technique for non-invasive kinematic evaluation of SIJ motion for this population. Further research on the use of this palpation-digitization technique in symptomatic population is warranted. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. A simply constructed but efficacious shock tester for high-g level shock simulation.

    Science.gov (United States)

    Duan, Zhengyong; Zhao, Yulong; Liang, Jing

    2012-07-01

    A simply constructed shock tester, different from existing drop table machines, is developed for high-g level shock environment simulation. The theoretical model, structure design, and working principle of the drop tester are described. A prototype device is set up, where a carbon fiber reinforced polymer with a high specific modulus is used. Using a Brüel & Kjær high-g accelerometer, experiments to verify the validity of the design are carried out and results are given. The maximum acceleration level is in excess of 60,000 g, limited only by the manual driving force.

  12. Neural-network-based single-sided non-enwrapping power loss tester

    CERN Document Server

    Passadis, K; Beckley, P

    2003-01-01

    It is preferable to be able to assess the power loss of electrical steels during production. When a single-sided tester is used, flux sensing is undertaken from one side only and hence some leakage flux above the strip may not captured by the sensing coils. Therefore, the disadvantage of a single-sided non-enwrapping tester lies in the measurement of the flux density in the material. A neural network was successfully used to 'predict' the correct level of flux density for accurate assessment of power loss.

  13. A scaling rule of indentation hardness of semiconductors

    Science.gov (United States)

    Yonenaga, Ichiro; Suzuki, Takayoshi

    2003-03-01

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

  14. 16 CFR Figure 4 to Subpart A of... - Flooring Radiant Panel Tester Schematic Low Flux End, Elevation

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Flooring Radiant Panel Tester Schematic Low Flux End, Elevation 4 Figure 4 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY... Standard Pt. 1209, Subpt. A, Fig. 4 Figure 4 to Subpart A of Part 1209—Flooring Radiant Panel Tester...

  15. Thermodynamic hardness and the maximum hardness principle

    Science.gov (United States)

    Franco-Pérez, Marco; Gázquez, José L.; Ayers, Paul W.; Vela, Alberto

    2017-08-01

    An alternative definition of hardness (called the thermodynamic hardness) within the grand canonical ensemble formalism is proposed in terms of the partial derivative of the electronic chemical potential with respect to the thermodynamic chemical potential of the reservoir, keeping the temperature and the external potential constant. This temperature dependent definition may be interpreted as a measure of the propensity of a system to go through a charge transfer process when it interacts with other species, and thus it keeps the philosophy of the original definition. When the derivative is expressed in terms of the three-state ensemble model, in the regime of low temperatures and up to temperatures of chemical interest, one finds that for zero fractional charge, the thermodynamic hardness is proportional to T-1(I -A ) , where I is the first ionization potential, A is the electron affinity, and T is the temperature. However, the thermodynamic hardness is nearly zero when the fractional charge is different from zero. Thus, through the present definition, one avoids the presence of the Dirac delta function. We show that the chemical hardness defined in this way provides meaningful and discernible information about the hardness properties of a chemical species exhibiting integer or a fractional average number of electrons, and this analysis allowed us to establish a link between the maximum possible value of the hardness here defined, with the minimum softness principle, showing that both principles are related to minimum fractional charge and maximum stability conditions.

  16. The relative effectiveness of testers during field surveillance for bovine tuberculosis in unrestricted low-risk herds in Ireland.

    Science.gov (United States)

    Clegg, T A; Duignan, A; More, S J

    2015-04-01

    In Ireland, new bovine tuberculosis (bTB) cases are detected using both field and abattoir surveillance. Field surveillance is conducted on all cattle annually using the single intradermal comparative tuberculin test (SICTT). Testing is reliant on the skills and experience of the tester and a broad range of factors may adversely affect test accuracy. There is considerable emphasis on quality control (QC) within the national programme and field inspection of testers has been conducted in Ireland for many years. Since 2008, inspection has been supplemented with quantitative performance reports, enabling testers to be evaluated and ranked using a range of performance indicators. The objectives of this study were first, to quantify the relative effectiveness of testers during field surveillance and, second, to assess whether there has been any change in the performance of testers between 2008 and 2011. Mixed logistic regression was used to assess the relative effectiveness of testers. The study population included all testers who carried out at least ten eligible tests in Ireland during 2008 or 2011. The outcome measure was a herd restriction at the eligible test. Results from the mixed model indicated that the variation by tester had significantly (p=0.039) decreased from 0.589 in 2008 to 0.426 in 2011, indicating an increase in consistency of testing, after accounting for other known risk factors. This study provides objective data on the variation in tester performance over time and the relative performance of testers during field surveillance in Ireland. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Reliability of knee joint range of motion and circumference measurements after total knee arthroplasty: does tester experience matter?

    Science.gov (United States)

    Jakobsen, Thomas Linding; Christensen, Malene; Christensen, Stine Sommer; Olsen, Marie; Bandholm, Thomas

    2010-09-01

    Two of the most utilized outcome measures to assess knee joint range of motion (ROM) and intra-articular effusion are goniometry and circumference, respectively. Neither goniometry nor circumference of the knee joint have been examined for both intra-tester and inter-tester in patients with total knee arthroplasty (TKA). The purpose of this study was to determine the intra-tester and inter-tester reliability of active and passive knee joint ROM and circumference in patients with TKA when administered by physiotherapists (testers) with different clinical experience. The design was an intra-tester, inter-tester and intra-day reliability study. Nineteen outpatients (10 females) having received a TKA were examined by an inexperienced and an experienced physiotherapist. Following a standardized protocol, active and passive knee joint ROM and circumference measurements were obtained using a universal goniometer and a tape measure, respectively. To establish reliability, intraclass correlation coefficients (ICC(2,1)) and smallest real difference (SRD) were calculated. The knee joint ROM and circumference measurements were generally reliable (ICC > 0.8) within and between physiotherapists (except passive knee extension). Changes in knee joint ROM of more than 6.6 degrees and 10 degrees (except active knee flexion) and knee joint circumference of more than 1.0 cm and 1.63 cm represent a real clinical improvement (SRD) or deterioration for a single individual within and between physiotherapists, respectively. Generally, the experienced tester recorded larger knee joint ROM and lower circumference values than that of the inexperienced tester. In clinical practice, we suggest that repeated knee goniometric and circumferential measurements should be recorded by the same physiotherapist in individual patients with TKA. Tester experience appears not to influence the degree of reliability. (c) 2009 John Wiley & Sons, Ltd.

  18. Effect of heat-treatment on the hardness and mechanical properties of Boron Alloyed Steel

    Directory of Open Access Journals (Sweden)

    bin Khiyon Mohammad Raffik

    2017-01-01

    Full Text Available In an automotive industry, hot stamped, die quenched structural components have been widely used to provide extra protection against crash intrusion. Boron alloyed steel exhibit limited ductility, but it also promotes improvement in impact performance. This study analyzed the effect of cooling rate on the hardness and energy absorption. Self-quenched specimens were heated to 850°C and cooled in air of room temperature, water at room temperature and cold water. Vickers hardness test and tensile test was then carried out to analyze the effect of different quenching rate. Self-quenched specimens were compared to the properties of the die-quenched specimens obtained from commercial automobile body. Result shows that boron steel with the highest cooling rate has the highest value of hardness but low in strength.

  19. High inter-tester reliability of the new mobility score in patients with hip fracture

    DEFF Research Database (Denmark)

    Kristensen, M.T.; Bandholm, T.; Foss, N.B.

    2008-01-01

    at the orthopaedic ward. Inter-tester reliability was evaluated using the intraclass correlation coefficient (ICC1.1) and the standard error of measurement (SEM). RESULTS: The ICC between the 2 physiotherapists was 0.98, 95% confidence interval (CI) 0.96-0.99 and the SEM was 0.42, 95% CI -0.40-1.24 New Mobility...

  20. High inter-tester reliability of the new mobility score in patients with hip fracture.

    Science.gov (United States)

    Kristensen, Morten Tange; Bandholm, Thomas; Foss, Nicolai Bang; Ekdahl, Charlotte; Kehlet, Henrik

    2008-07-01

    To assess the inter-tester reliability of the New Mobility Score in patients with acute hip fracture. An inter-tester reliability study. Forty-eight consecutive patients with acute hip fracture at a median age of 84 (interquartile range, 76-89) years; 40 admitted from their own home and 8 from nursing homes to an acute orthopaedic hip fracture unit at a university hospital. The New Mobility Score, which evaluates the prefracture functional level with a score from 0 (not able to walk at all) to 9 (fully independent), was assessed by 2 independent physiotherapists at the orthopaedic ward. Inter-tester reliability was evaluated using the intraclass correlation coefficient (ICC1.1) and the standard error of measurement (SEM). The ICC between the 2 physiotherapists was 0.98, 95% confidence interval (CI) 0.96-0.99 and the SEM was 0.42, 95% CI -0.40-1.24 New Mobility Score points. No systematic between-rater bias was observed (p>0.05). Patients who were scored differently by the 2 physiotherapists had significantly lower mental scores (p=0.02). The inter-tester reliability of the New Mobility Score is very high and can be recommended to evaluate the prefracture functional level in patients with acute hip fracture.

  1. Dynamic simulation of a displacement-controlled total knee replacement wear tester.

    Science.gov (United States)

    Lanovaz, J L; Ellis, R E

    2008-07-01

    This paper presents a dynamic finite element method (FEM) model of a commercial displacement-controlled total knee replacement (TKR) wear tester. The first goal of the study was to validate the model, which included both the wear tester and the TKR components. Convergence simulations and experimental testing were performed. These included a novel experimental determination of the coefficient of friction and an evaluation of predicted joint contact areas by comparing simulation results with experimental data collected using pressure-sensitive film. The second goal of this study was to develop a procedure for implementing force-based testing protocols on a displacement-controlled TKR wear tester. A standard force-based cyclic wear-testing protocol was simulated using the FEM model and resulting displacement waveforms were extracted. These were used as control inputs to the physical wear tester and an experimental wear test was performed. Reaction loads on the tibial components were measured and compared with the simulated results. The model was capable of accurately predicting the tibial loads throughout the test cycle, verifying the model's contact mechanics. The study demonstrated the use of computational modelling to convert a force-based testing protocol into displacement-based control parameters for use in a displacement-controlled mechanical testing system.

  2. Homemade abrasion tester and its application for abrasion resistance testing of crease points on down fabrics

    Directory of Open Access Journals (Sweden)

    Yidie GUAN

    2017-02-01

    Full Text Available In order to explore a new method for testing the fabric abrasion resistance, a homemade abrasion tester is designed and manufactured. The principle, structure and test method of the homemade abrasion tester are introduced. The crease points on fabrics are rubbed using the abrasion tester under certain air pressure and the abrasion of fabrics is reflected on real time through the change of gas flow. The change of gas flow is converted into equivalent aperture by Bernoulli equation and the equivalent aperture is used to evaluate the abrasion resistance of the crease point on fabric. Three measuring parameters of friction velocity, gas pressure and fabric thickness influencing on the abrasion resistance of crease point on down fabrics are tested by orthogonal experiment. The influence of the three elements on the abrasion resistance is analyzed. The results show that the homemade abrasion tester can represent the abrasion resistance of crease point under certain conditions. The gas pressure and fabric thickness have significant influence on the abrasion resistance, but the influence of friction velocity is not significant. Above all, the gas pressure has the most high influence. The research result prevides reference for improving the abrasion resistance of crease points on down fabrics.

  3. An innovative tester system for measuring mechanical property of foundry molding sand

    Directory of Open Access Journals (Sweden)

    Zuxi XIE

    2004-11-01

    Full Text Available A new intelligent tester system for measuring multiple mechanical properties of foundry molding sand is introduced and has been patented for the invention in China. The testing process can be simutaneosly controlled wth a build-in chip microcomputer communicating with a PC through a serial port. The testing system pplies dynamic testing technology. During the measurement for compression, relaxation, shearing and tensile processes of sand specimens, the corresponding characteristic curves and eight mechanical property parameters can be obtained in a short time, simply by consecutively testing on four sand specimens. The properties and parameters to be measurable by the tester include compressive strength, elastic modulus, plastic deformation threshold, springback potential, shear strength, shear deformation limit, toughness and tensile strength. These properties and parameters for sand specimens can be defined as the corresponding characteristic curves with precise physical meanings, carried out by the tester. Two of them, namely plastic deformation threshold and springback potential, as well as their testing methods, have been invented for the first time. The testing system applying advanced data measurement technology as well as performing excellent functions is an important breakthrough and creativity in foundry molding sand property testing field. The parameters acquired by the testing system are stable, accurate and reliable. The test data can be instantly diaplayed or printed out or stored in the PC. As evidence, many experimental data obtained by the tester practically from bth laboratory and foundry floor tests indicate that the testr system can be widely applied in foundry industry.

  4. Sensitivity of Turbutester and Accuhaler tester in asthmatic children and adolescents.

    Science.gov (United States)

    Manuyakorn, Wiparat; Direkwattanachai, Chalerat; Benjaponpitak, Suwat; Kamchaisatian, Wasu; Sasisakulporn, Cherapat; Teawsomboonkit, Wanlapa

    2010-02-01

    Dry powder inhalers (DPI) are alternative devices for delivering medication for treatment of asthma. The amount of drug delivery to the lungs is directly influenced by peak inspiratory flow rate (PIFR). A minimum PIFR of -30 L/min is needed for the Turbuhaler and Accuhaler. In order to evaluate the sensitivity of the Turbutester and Accuhaler tester in detecting the minimum and optimum PIFR for the Turbuhaler and Accuhaler in asthmatic children, PIFR was measured using the In-Check Dial through the internal resistance of the Turbuhaler and Accuhaler and compared according to the child's ability to make a whistle sound via both testers. A total of 259 asthmatic children were studied: 20 pre-school children, aged 5-6 years; 174 school-age children, aged 7-12 years; and 65 adolescents, aged 13-18 years. The sensitivity of the Turbutester and Accuhaler tester to detect optimum PIFR were 98.40% and 97.2%, respectively. In the comparison among age groups, the sensitivity of the Accuhaler tester to detect optimum or minimum PIFR for the Accuhaler was 95%, 97.7% and 95.4%, respectively. The sensitivity of the Turbutester to detect optimum PIFR for the Turbuhaler was 94.4%, 98.8% and 98.5%, respectively. The sensitivity of the Turbutester to detect minimum PIFR for the Turbuhaler was 94.7%, 100% and 100%, respectively. There were no significant differences in percentage of having optimum or minimum PIFR among asthma severity and current device usage in all age groups. Most children aged at least 5 years could generate enough PIFR to use dry powder inhaler devices. Both the Turbutester and Accuhaler tester were found to have high sensitivity in detecting optimum and minimum required PIFR.

  5. Tensile properties and hardness of two types of 11Cr-ferritic/martensitic steel after aging up to 45,000 h

    Directory of Open Access Journals (Sweden)

    Y. Yano

    2016-12-01

    Full Text Available The relationship among tensile strength, Vickers hardness and dislocation density for two types of 11Cr-ferritic/martensitic steel (PNC-FMS was investigated after aging at temperatures between 400 and 800°C up to 45,000h and after neutron irradiation. A correlation between tensile strength and Vickers hardness was expressed empirically. The linear relationship for PNC-FMS wrapper material was observed between yield stress and the square of dislocation density at RT and aging temperature according to Bailey–Hirsch relation. Therefore, it was clarified that the correlation among dislocation density, tensile strength and Vickers hardness to aging temperature was in good agreement. On the other hand, the relationship between tensile strength ratio when materials were tested at aging temperature and Larson–Miller parameter was also in excellent agreement with aging data between 400 and 700°C. It was suggested that this correlation could use quantitatively for separately evaluating irradiation effects from neutron irradiation data containing both irradiation and aging effects.

  6. Measurement Performance Assessment: Dynamic Calibration Compared with Static Calibration Method for Roller Tester of Vehicle Brake Force

    Directory of Open Access Journals (Sweden)

    Guan Xu

    2014-05-01

    Full Text Available The measurement performance of the roller tester for the vehicle brake force is evaluated by both proposed dynamic calibration and traditional static calibration to find an effective way for ensuring the vehicle safety. Three static parameters, brake force error of a single bench, difference of the left and right benches, and measurement repeatability, are verified to be eligible in the experiments. However, the experimental results of the dynamic calibration prove that the same brake tester fails on the repeatability with a 10.4% error. The dynamic calibration method improves the measurement performance of the brake tester in practical applications.

  7. Tooth enamel surface micro-hardness with dual species Streptococcus biofilm after exposure to Java turmeric (Curcuma xanthorrhiza Roxb.) extract

    Science.gov (United States)

    Isjwara, F. R. G.; Hasanah, S. N.; Utami, Sri; Suniarti, D. F.

    2017-08-01

    Streptococcus biofilm on tooth surfaces can decrease mouth environment pH, thus causing enamel demineralization that can lead to dental caries. Java Turmeric extract has excellent antibacterial effects and can maintain S. mutans biofilm pH at neutral levels for 4 hours. To analyze the effect of Java Turmeric extract on tooth enamel micro-hardness, the Java Turmeric extract was added on enamel tooth samples with Streptococcus dual species biofilm (S. sanguinis and S. mutans). The micro-hardness of enamel was measured by Knoop Hardness Tester. Results showed that Curcuma xanthorrhiza Roxb. could not maintain tooth enamel surface micro-hardness. It is concluded that Java Turmeric extract ethanol could not inhibit the hardness of enamel with Streptococcus dual species biofilm.

  8. Kinetics of borided gear steels

    Indian Academy of Sciences (India)

    The boride layer was characterized by optical microscopy, X-ray diffraction technique and microVickers hardness tester. X-ray diffraction analysis of boride layers on the surface of the steels revealed the existence of FeB, Fe2B, CrB and Cr2B compounds. The thickness of the boride layer increases by increasing boriding ...

  9. Evaluation of WC-9Co-4Cr laser surface alloyed coatings on stainless steel

    CSIR Research Space (South Africa)

    Obadele, A

    2011-07-01

    Full Text Available spectrometer (EDS), while the phase changed were observed using x-ray diffraction (XRD). The surface hardness was determined using the Vickers microhardness tester. The decomposition of WC-9Co-4Cr into W2C, C and W is as a result of low heat of formation of WC...

  10. Mechanical characterization of microwave sintered zinc oxide

    Indian Academy of Sciences (India)

    Unknown

    II, Echo Ultrasound, USA). A 15 MHz transducer was used for this purpose. For each sintering condition, at least three to five samples were used to obtain the average data. The hardness data was obtained for the load range. (0⋅1–20 N) using a microhardness tester fitted with a. Vicker's square pyramidal indenter. Similarly ...

  11. Modular, capacitive voltage tester for MV switching systems; Modulares, kapazitives Spannungspruefsystem fuer MS-Schaltanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Ader, T. [ABB Calor Emag Mittelspannung GmbH (Germany); Jenke, G. [Georg Jordan GmbH, Siegburg (Germany)

    2001-10-01

    Capacitive voltage testers are reliable, indispensable components of MV switching systems. New designs and automatic operation make new demands. The contribution shows practical solutions and outlines future trends. [German] Kapazitive Spannungspruefsysteme haben sich seit vielen Jahren als zuverlaessige, unverzichtbare Komponenten in Mittelspannungsschaltanlagen erwiesen. Weiterentwicklungen des Schaltanlagendesigns sowie eine zunehmende Automatisierung der Betriebsfuehrung stellen neue Forderungen an diese Spannungspruefsysteme. Der Beitrag zeigt praxisnah Loesungsmoeglichkeiten zur Umsetzung dieser Forderungen auf und liefert einen Ausblick auf zukuenftige Entwicklungen. (orig.)

  12. Review of LOX Bearing and Seal Materials Tester (BSMT) radial load system

    Science.gov (United States)

    Dufrane, K. F.; Kannel, J. W.

    1984-01-01

    Problems concerning the bearings in the high pressure oxygen turbopumps (HPOTP) were investigated. The tasks involved: failure analyses, bearing dynamics calculations, lubrication studies, wear studies, and analyses of thermal transients. The radial load system on MSFC's bearing and seal tester used to study components for the HPOTP in liquid oxygen (LOX) is analyzed and the wear behavior of AISI 440C steel with polytetrafluoroethylene (PTFE) lubrication is studied.

  13. An automated digital data collection and analysis system for the Charpy Impact Tester

    Science.gov (United States)

    Kohne, Glenn S.; Spiegel, F. Xavier

    1994-01-01

    The standard Charpy Impact Tester has been modified by the addition of a system of hardware and software to improve the accuracy and consistency of measurements made during specimen fracturing experiments. An optical disc, light source, and detector generate signals that indicate the pendulum position as a function of time. These signals are used by a computer to calculate the velocity and kinetic energy of the pendulum as a function of its position.

  14. Comparison of testers in the selection of S3 families obtained from the UENF-14 variety of popcorn

    Directory of Open Access Journals (Sweden)

    Guilherme Ferreira Pena

    2016-01-01

    Full Text Available ABSTRACT The use of topcross has proven to be an interesting option for the maize crop; however, for the popcorn, there is little information about the choice of the appropriate tester. In this context, this study aimed to analyze four testers including two open pollinated varieties(BRS Angela and UENF-14, one topcross hybrid (IAC125 and a line (P2, to evaluate the combining ability of 50 S3 families of popcorn, obtained from the UENF-14 variety. Popcorn families were evaluated for grain yield (GY and popping expansion (PE. The estimates of general and specific combining abilities were obtained and the discrimination of each tester through differentiation index was carried out. The testers BRS Angela (for GY and IAC 125 (for PE were the most adequate, when combined with the best S3 families derived from UENF-14, for the production of popcorn hybrids for the Northern and Northwestern Fluminense Regions.

  15. Trial manufacture of rotary friction tester and frictional force measurement of metals

    CERN Document Server

    Abe, T; Kanari, M; Tanzawa, S

    2002-01-01

    In the plasma confinement type fusion reactor, in-vessel structures such as a blanket module slide at the joints each other when plasma disruption occurs, and then frictional heat is generated there. Therefore, for the selection of material and the use as the design data, it is important to understand the frictional characteristics of metals and ceramic films in the vacuum. In the present study, we have manufactured a prototype of rotary friction tester and examined the performances of the tester. The frictional characteristics of metals in the room air was measured using the friction tester, and the results obtained are as follows. A drifting friction force for a constant time and a friction force during the idling were 98 mN and 225 mN, respectively. These values were sufficiently small as compared to pressing load (9.8 - 57.8 N) used in the friction test. In a friction force measurement of stainless steel, dynamic friction force obeyed Amontons' law which indicated that dynamic friction force is not depend...

  16. Gas-pressurized dispersive powder flow tester for low volume sample characterization.

    Science.gov (United States)

    Majid, Ainnur Marlyana Abd; Wong, Tin Wui

    2013-05-01

    The conventional powder flow testers require sample volumes larger than 40g and are met with experimental hiccups due to powder cohesion. This study designed a gas-pressurized dispersive powder flow tester where a high velocity air is used to disaggregate powder (9g) and eliminate its cohesion. The pressurized gas entrained solid particles leaving an orifice where the distance, surface area, width and weight of particle dispersion thereafter are determined as flow index. The flow indices of seven lactose grades with varying size, size distribution, shape, morphology, bulk and tapped densities characteristics were examined. They were compared against Hausner ratio and Carr's index parameters of the same powder mass. Both distance and surface area attributes of particle dispersion had significant negative correlations with Hausner ratio and Carr's index values of lactose. The distance, surface area and ease of particle dispersion varied proportionately with circular equivalent, surface weighted mean and volume weighted mean diameters of lactose, and inversely related to their specific surface area and elongation characteristics. Unlike insensitive Hausner ratio and Carr's index, an increase in elongation property of lactose particles was detectable through reduced powder weight loss from gas-pressurized dispersion as a result of susceptible particle blockage at orifice. The gas-pressurized dispersive tester is a useful alternative flowability measurement device for low volume and cohesive powder. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Quantitative assessment of increased sensitivity of chronic laminitic horses to hoof tester evoked pain.

    Science.gov (United States)

    Viñuela-Fernandez, I; Jones, E; McKendrick, I J; Molony, V

    2011-01-01

    To evaluate quantitative sensory testing (QST) of the feet of laminitic horses using a power-assisted hoof tester. Hoof Compression Thresholds (HCTs) can be measured reliably and are consistently lower in horses with chronic laminitis than in normal horses. HCTs of chronic laminitic (n=7) and normal horses (n=7) were repeatedly measured using a hydraulically powered and feedback controlled hoof tester. Data from 2 tests, at 3 sites in both forefeet, during 3 sessions were collected and statistically analysed using linear mixed models. The mean±s.e. HCT for the laminitic horses was 29.6±3.5 kg/cm2 and for horses in the normal group was 59.8±4.3 kg/cm2. Residual variance was the largest of the error components and was greater (Ptester. The level of variability found indicates that, under these conditions, treatments may need to produce at least a 40% improvement to be detected. Simplification of the hoof tester, training of the horse and repeated testing may permit the method to be used clinically to detect changes in the HCTs of individual laminitic horses but these potential improvements will require further investigation. Measurement of HCTs can provide an additional means for assessing the effectiveness of treatments for alleviation of chronic equine laminitis. © 2010 EVJ Ltd.

  18. A dynamic tester to evaluate the thermal and moisture behaviour of the surface of textiles.

    Science.gov (United States)

    Li, Wenbin; Xu, Weilin; Wang, Hao; Wang, Xin

    2016-01-01

    The thermal and moisture behaviour of the microclimate of textiles is crucial in determining the physiological comfort of apparel, but it has not been investigated sufficiently due to the lack of particular evaluation techniques. Based on sensing, temperature controlling and wireless communicating technology, a specially designed tester has been developed in this study to evaluate the thermal and moisture behaviour of the surface of textiles in moving status. A temperature acquisition system and a temperature controllable hotplate have been established to test temperature and simulate the heat of human body, respectively. Relative humidity of the surface of fabric in the dynamic process has been successfully tested through sensing. Meanwhile, wireless communication technology was applied to transport the acquired data of temperature and humidity to computer for further processing. Continuous power supply was achieved by intensive contact between an elastic copper plate and copper ring on the rotating shaft. This tester provides the platform to evaluate the thermal and moisture behaviour of textiles. It enables users to conduct a dynamic analysis on the temperature and humidity together with the thermal and moisture transport behaviour of the surface of fabric in moving condition. Development of this tester opens the door of investigation on the micro-climate of textiles in real time service, and eventually benefits the understanding of the sensation comfort and wellbeing of apparel wearers. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Tester og testtilbakemeldinger som direkte bidragsytere til dypere læring blant studenter

    Directory of Open Access Journals (Sweden)

    Henrik Herrebrøden

    2014-11-01

    Full Text Available Denne artikkelen diskuterer forskning som tilsier at tester og testtilbakemeldinger kan bidra til dypere læring blant studenter. Testing har vist seg å forbedre langtidshukommelsen av innlært kunnskap sammenlignet med repetert lesing, noe som kalles for testeffekten. For at testeffekten skal optimaliseres, bør tester utformes med mål om å bidra til dyp prosessering av innlært kunnskap. Testtilbakemeldingers rolle i utdanning kan være å bidra til økt metakognitiv selvregulering blant studenter. For at selvregulering skal promoteres best mulig, bør testtilbakemeldinger inneholde utdypende informasjon. Samlet ser tester og testtilbakemeldinger ut til å være nyttige læringsverktøy og potensielle bidragsytere til dypere læring blant studenter.AbstractThis article discusses research supporting that tests and test feedback are learning tools that may promote deeper learning among students. Testing improves long-term retention of knowledge compared to repeated study, a phenomenon known as the testing effect. In order to promote the testing effect, tests should facilitate deep processing of knowledge among students. Test feedback has the potential to increase students’ metacognitive self-regulation. For this type of metacognition to be enhanced, feedback should contain elaborate information. Conclusively, tests and test feedback appear to be valuable learning tools and potential promoters of deeper learning.

  20. Measurement Performance Assessment: Dynamic Calibration Compared with Static Calibration Method for Roller Tester of Vehicle Brake Force

    OpenAIRE

    Guan Xu; Jian Su; Rong Chen; Hongda Pan; Libin Zhang; Xing Wang

    2014-01-01

    The measurement performance of the roller tester for the vehicle brake force is evaluated by both proposed dynamic calibration and traditional static calibration to find an effective way for ensuring the vehicle safety. Three static parameters, brake force error of a single bench, difference of the left and right benches, and measurement repeatability, are verified to be eligible in the experiments. However, the experimental results of the dynamic calibration prove that the same brake tester ...

  1. Comprehensive hard materials

    CERN Document Server

    2014-01-01

    Comprehensive Hard Materials deals with the production, uses and properties of the carbides, nitrides and borides of these metals and those of titanium, as well as tools of ceramics, the superhard boron nitrides and diamond and related compounds. Articles include the technologies of powder production (including their precursor materials), milling, granulation, cold and hot compaction, sintering, hot isostatic pressing, hot-pressing, injection moulding, as well as on the coating technologies for refractory metals, hard metals and hard materials. The characterization, testing, quality assurance and applications are also covered. Comprehensive Hard Materials provides meaningful insights on materials at the leading edge of technology. It aids continued research and development of these materials and as such it is a critical information resource to academics and industry professionals facing the technological challenges of the future. Hard materials operate at the leading edge of technology, and continued res...

  2. Age-related changes in hardness and modulus of elasticity of dentine.

    Science.gov (United States)

    Senawongse, Pisol; Otsuki, Masayuki; Tagami, Junji; Mjör, Ivar

    2006-06-01

    Little knowledge has been clarified about the relationship between the morphological and physical changes of dentine during aging. The purpose of this study was to clarify the modulus of elasticity and hardness related to the morphological changes of dentine by aging using a transmitted light microscope (TLM) and a nano-hardness tester (NHT). Aged human molars and young third molars were used. The dentine morphology was observed under a TLM. The hardness and Young's modulus of elasticity related to the morphologic study were evaluated with an NHT. The thickness of mantle dentine and globular dentine of aged teeth were less than that of young teeth. Transparent dentine was observed only underneath the attrition of young teeth. Reactionary tertiary dentine formed and a "dark zone" was found at the junction between physiologic secondary and reactionary dentine only in aged teeth. At the mantle dentine, hardness and modulus of elasticity of aged dentine were higher than those of young dentine. The reactionary dentine in aged teeth and newly developed secondary dentine in young teeth demonstrated lower modulus of elasticity and hardness than those of other circumpulpal dentine. Relatively low modulus of elasticity and hardness were observed at the zone between secondary and reactionary dentine. Changes in dentine due to aging resulted in transformation of morphological features causing changes to their hardness and modulus of elasticity at the explicit areas such as the increase of hardness and modulus of elasticity at mantle dentin and the reduction of these properties at the "dark zone" that found in aged teeth.

  3. Comparison of a saliva wetness tester and a moisture-checking device in patients with maxillary obturator prostheses.

    Science.gov (United States)

    Murakami, Mamoru; Nishi, Yasuhiro; Kamashita, Yuji; Nagaoka, Eiichi

    2014-06-01

    Examination of dry mouth in postoperative oral tumour patients should ideally be performed simply and quickly at the chair side. Moisture-checking devices and saliva wetness testers are available for such moisture measurement. Previous studies have reported that moisture-checking devices are useful to examine dry mouth in patients with maxillary obturator prostheses. However, because the measurement principles of saliva wetness testers differ from those of moisture-checking devices, diagnosis by the two devices may result in diagnostic disagreement. The purpose of the present study was to compare the usefulness of a saliva wetness tester with a moisture-checking device for patients with maxillary obturator prostheses. Oral moisture was measured with a moisture-checking device and a saliva wetness tester in 30 subjects with maxillary obturator prostheses. These measurements were performed five times at the lingual mucosa, and mean values of each measurement were calculated. The reference value for moisture measurements with the moisture-checking device was 29%, and that with the saliva wetness tester was 3 mm. Subjects were classified as having dry mouth when their moisture measurements were less than the reference values. The diagnostic results of the saliva wetness tester were in agreement with those of the moisture-checking device. The respective moisture measurements showed a significant positive correlation (r=0.88, ptesters are as useful as moisture-checking devices to examine dry mouth in patients with maxillary obturator prostheses. © 2013 The Gerodontology Society and John Wiley & Sons A/S.

  4. Patient perceptions and expectations of an anticoagulation service: a quantitative comparison study of clinic-based testers and patient self-testers.

    Science.gov (United States)

    Money, Arthur G; Barnett, Julie; Kuljis, Jasna; Duffin, Debbie

    2015-12-01

    Government initiatives see the provision of technology-assisted self-care as one of the key areas in which there is capacity for improving quality of care whilst reducing costs. However, levels of patient engagement in self-testing and management (STM) remain low. Little emphasis has been placed on understanding the patients' perspectives of the reasons for this limited engagement. Typically, patient engagement in STM is achieved via the provision of patient education programmes, which aim to enable patients to make the changes necessary to become competent self-carers. However, placing the onus to change on the individual patient is unrealistic. If levels of patient engagement are to be improved, patient needs and expectations of clinical services must be better understood and service provision must be adapted accordingly. Explore patient perceptions and expectations of clinical service provision and their views of having and making choices about care. Participants [N = 191, 103 patient self-tester managers (PSTMs) and 87 clinic-based testers (CBTs)] completed the SERVQUAL and ChQ instruments to capture perspectives on service quality and choice, respectively. A comparative statistical analysis explored the similarities and differences between PSTMs' and CBTs' responses. Clinic-based testers' perceptions of service quality were significantly more positive than PSTMs', as were their expectations of the 'tangible' aspects of service delivery. PSTMs' expectations of service quality were significantly higher than their perceptions. PSTMs attributed significantly more value to making choices compared with CBTs. To close the gap between PSTMs expectations and perceptions of service quality and better cater for their choice preferences, service providers may benefit from taking into account the following practice considerations: maintain frequent, timely, personalised and direct interactions with PSTMs; prioritise investment in resources to facilitate patient

  5. Analysis of residual stress and hardness in regions of pre-manufactured and manual bends in fixation plates for maxillary advancement.

    Science.gov (United States)

    Araújo, Marcelo Marotta; Lauria, Andrezza; Mendes, Marcelo Breno Meneses; Claro, Ana Paula Rosifini Alves; Claro, Cristiane Aparecida de Assis; Moreira, Roger William Fernandes

    2015-12-01

    The aim of this study was to analyze, through Vickers hardness test and photoelasticity analysis, pre-bent areas, manually bent areas, and areas without bends of 10-mm advancement pre-bent titanium plates (Leibinger system). The work was divided into three groups: group I-region without bend, group II-region of 90° manual bend, and group III-region of 90° pre-fabricated bends. All the materials were evaluated through hardness analysis by the Vickers hardness test, stress analysis by residual images obtained in a polariscope, and photoelastic analysis by reflection during the manual bending. The data obtained from the hardness tests were statistically analyzed using ANOVA and Tukey's tests at a significance level of 5 %. The pre-bent plate (group III) showed hardness means statistically significantly higher (P < 0.05) than those of the other groups (I-region without bends, II-90° manually bent region). Through the study of photoelastic reflection, it was possible to identify that the stress gradually increased, reaching a pink color (1.81 δ / λ), as the bending was performed. A general analysis of the results showed that the bent plate region of pre-bent titanium presented the best results.

  6. Hardness loss and microstructure evolution of 90% hot-rolled pure tungsten at 1200-1350°C

    DEFF Research Database (Denmark)

    Yu, Ming; Wang, Kang; Zan, Xiang

    2017-01-01

    Tungsten is a promising plasma-facing material because of its low sputtering yield, high melting point and high thermal conductivity. The hardness loss and microstructure evolution of pure tungsten hot-rolled to 90% thickness reduction is investigated by isothermal annealing at temperature range...... of 1200-1350°C. Changes in the mechanical properties caused by recovery and recrystallization during heat treatment are detected by Vickers hardness measurements. Additionally, the microstructural evolution is analyzed with light optical microscopy and X-ray diffraction. The results indicate...... that the hardness evolution can be divided into two stages: recovery and recrystallization. Recrystallization of W90 in the temperature range of 1200 to1350°C is governed by the same activation energy as grain boundary diffusion. The average recrystallized grain size is larger for lower annealing temperatures....

  7. Hardness and Second Phase Percentage of Ni-Ti-Hf Compounds After Heat Treatment at 700C

    Science.gov (United States)

    Stanford, Malcolm K.

    2017-01-01

    The Vickers hardness and second phase precipitation of three ternary intermetallic Ni-Ti-Hf compounds containing either 1, 3 or 5 at.% Hf were compared to 60-Nitinol (55 at.% Ni - 45 at.% Ti). Heat treatment either at 700 C or with a subsequent aging step, hardened the 3 and 5 at.% Hf-containing ternaries to approximately 620 HV (56 HRC). Heat treatment increased the hardness of the 1 at.% Hf compound by more than 25 percent. Average hardness of the 3 and 5 at.% Hf ternaries, though higher than that of the binary Ni-Ti or the Ni-Ti-Hf compound containing 1 at.% Hf, appeared to be fairly insensitive to the different heat treatments. There was a drastic reduction of fatigue-enhancing second phase precipitates for the 5 at.% Hf ternaries compared to the other compounds. These results should guide materials selection for development of aerospace componentry.

  8. Hardness Evaluation of Composite Resins Cured with QTH and LED

    Directory of Open Access Journals (Sweden)

    Behnaz Esmaeili

    2014-03-01

    Full Text Available Background and aims. Today light cured composites are widely used. Physical and mechanical properties of composites are related to the degree of conversion. Light curing unit (LCU is an important factor for composite polymerization. Aim of this study is evaluation of composite resins hardness using halogen and LED light curing units. Materials and methods. In this study, 30 samples of Filtek Z250 and C-Fill composite resins were provided. Samples were light cured with Ultralume2, Valo and Astralis7. Vickers hardness number (VHN was measured in 0, 1, 2 mm depth. Statistical analysis used: Data were analysed by SPSS software and compared with each other by T-test, one-way and twoway ANOVA and Post-hoc Tukey test. Results. In Filtek Z250, at top surface, VHN of Ultralume2 was higher than VHN of Valo (P = 0.02 and Astralis7 (P = 0.04, but in depth of 1, 2 mm, VHN of Ultralume2 and Astralis7 were almost the same and both LCUs were more than Valo which the difference between Ultralume2 and Valo was significant in depth of 1mm (0.05 and 2mm (0.02. In C-Fill composite, at top surface, Astralis7 showed higher VHN, but in depth of 2 mm, performance of all devices were rather similar. Conclusion. In Z250, which contains camphorquinone initiator, light cure LED Ultra-lume2 with narrow wavelength showed higher hardness number than Valo. In C-fill, in top surface, Astralis7 with more exposure time, resulted higher VHN. But In depth of 2 mm, various light curing devices had rather similar hardness number.

  9. Effects of hardness and test temperature on the stress-corrosion cracking susceptibility of carbon steel in simulated BWR environment; Koon koatsu sui kankyo ni okeru tansoko no oryoku fushokuware kanjusei ni oyobosu kodo, oyobi shiken ondo no eikyo hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, G.; Akashi, M. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    1998-03-15

    An SSRT test and a CBB test were carried out on carbon steel and heat treated materials applied with bead welding of single pass simulating fillet welding in oxygen-enriched high-temperature water environment, and the stress-corrosion cracking susceptibility was evaluated. Highly hard welding heat affected zones with Vickers hardness of more than 400 have grain boundary stress-corrosion cracking susceptibility. However, a structure whose high hardness has been realized by tempering treatment has no grain boundary stress-corrosion cracking susceptibility. In the SSRT test, stress-corrosion cracking fractured face rate rises with rising test temperature, resulting in stress-corrosion cracking susceptibility shown even at lower hardness. On the other hand in the CBB test, a large number of relatively shallow cracks are generated down to low hardness at temperatures below 190 degC, while the number of cracking occurrence decreases as the temperature rises. However, deep cracks increase. In the CBB test on tempered heat treatment materials, the fact that stress-corrosion cracking can occur in test pieces with Vickers hardness of 165, which is nearly the same as that for the base material, proves that no lower limit hardness exists practically in occurrence of stress-corrosion cracking in carbon steel. 13 refs., 12 figs., 2 tabs.

  10. Hard probes 2006 Asilomar

    CERN Multimedia

    2006-01-01

    "The second international conference on hard and electromagnetic probes of high-energy nuclear collisions was held June 9 to 16, 2006 at the Asilomar Conference grounds in Pacific Grove, California" (photo and 1/2 page)

  11. Crystal Indentation Hardness

    Directory of Open Access Journals (Sweden)

    Ronald W. Armstrong

    2017-01-01

    Full Text Available There is expanded interest in the long-standing subject of the hardness properties of materials. A major part of such interest is due to the advent of nanoindentation hardness testing systems which have made available orders of magnitude increases in load and displacement measuring capabilities achieved in a continuously recorded test procedure. The new results have been smoothly merged with other advances in conventional hardness testing and with parallel developments in improved model descriptions of both elastic contact mechanics and dislocation mechanisms operative in the understanding of crystal plasticity and fracturing behaviors. No crystal is either too soft or too hard to prevent the determination of its elastic, plastic and cracking properties under a suitable probing indenter. A sampling of the wealth of measurements and reported analyses associated with the topic on a wide variety of materials are presented in the current Special Issue.

  12. Assessment of the hardness of different orthodontic wires and brackets produced by metal injection molding and conventional methods.

    Science.gov (United States)

    Alavi, Shiva; Kachuie, Marzie

    2017-01-01

    This study was conducted to assess the hardness of orthodontic brackets produced by metal injection molding (MIM) and conventional methods and different orthodontic wires (stainless steel, nickel-titanium [Ni-Ti], and beta-titanium alloys) for better clinical results. A total of 15 specimens from each brand of orthodontic brackets and wires were examined. The brackets (Elite Opti-Mim which is produced by MIM process and Ultratrimm which is produced by conventional brazing method) and the wires (stainless steel, Ni-Ti, and beta-titanium) were embedded in epoxy resin, followed by grinding, polishing, and coating. Then, X-ray energy dispersive spectroscopy (EDS) microanalysis was applied to assess their elemental composition. The same specimen surfaces were repolished and used for Vickers microhardness assessment. Hardness was statistically analyzed with Kruskal-Wallis test, followed by Mann-Whitney test at the 0.05 level of significance. The X-ray EDS analysis revealed different ferrous or co-based alloys in each bracket. The maximum mean hardness values of the wires were achieved for stainless steel (SS) (529.85 Vickers hardness [VHN]) versus the minimum values for beta-titanium (334.65 VHN). Among the brackets, Elite Opti-Mim exhibited significantly higher VHN values (262.66 VHN) compared to Ultratrimm (206.59 VHN). VHN values of wire alloys were significantly higher than those of the brackets. MIM orthodontic brackets exhibited hardness values much lower than those of SS orthodontic archwires and were more compatible with NiTi and beta-titanium archwires. A wide range of microhardness values has been reported for conventional orthodontic brackets and it should be considered that the manufacturing method might be only one of the factors affecting the mechanical properties of orthodontic brackets including hardness.

  13. Hardness amplification in nondeterministic logspace

    OpenAIRE

    Gupta, Sushmita

    2007-01-01

    A hard problem is one which cannot be easily computed by efficient algorithms. Hardness amplification is a procedure which takes as input a problem of mild hardness and returns a problem of higher hardness. This is closely related to the task of decoding certain error-correcting codes. We show amplification from mild average case hardness to higher average case hardness for nondeterministic logspace and worst-to-average amplification for nondeterministic linspace. Finally we explore possible ...

  14. Inter-and intra-tester reliability of a battery of cervical movement control dysfunction tests.

    Science.gov (United States)

    Segarra, V; Dueñas, L; Torres, R; Falla, D; Jull, G; Lluch, E

    2015-08-01

    Apart from the cranio-cervical flexion test and the deep neck flexor endurance test, evidence related to reliability of cervical movement control dysfunction tests is lacking. This study investigated the inter- and intra-tester reliability of a battery of cervical movement control dysfunction tests and the effect of clinician experience on reliability in 15 patients with chronic neck pain and 17 non-neck pain controls. In addition, it explored whether impaired performance on this battery of tests was more frequently observed in the neck pain group. Inter and intra-tester reliability study. Participants were videotaped while performing a battery of nine active cervical movement control dysfunction tests. Two physiotherapists, with different levels of experience, independently rated all tests on two occasions two weeks apart. They were masked to participants' neck pain or non-neck pain status. Inter-tester reliability for the complete battery of tests was substantial (κ = 0.69; 95% CI: 0.62, 0.76). Intra-rater reliability values for the expert (κ = 0.86; 95% CI: 0.79, 0.92) and novice (κ = 0.76; 95% confidence intervals (CI): 0.68, 0.84) were overall comparable suggesting that novices can achieve good accuracy with the battery of tests if trained. The frequency of impaired performances in cervical movement control dysfunction tests was low and comparable between groups. Only two tests achieved a greater number of impaired ratings in the patient group. Although reliable, further research in larger neck pain populations is required to explore this battery of tests, in order to establish their diagnostic accuracy for identifying clinically relevant cervical movement control dysfunction. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Minimal phototoxic dose (MPD) measurements for topical photochemotherapy using a semiautomated MPD tester.

    Science.gov (United States)

    Al-Ismail, D; Edwards, C; Al-Ofi, O; Anstey, A V

    2013-09-01

    The traditional method of assessing minimal phototoxic dose (MPD) prior to photochemotherapy with psoralen-ultraviolet A (PUVA) is inconvenient and cannot directly determine PUVA start doses. A handheld minimal erythema dose UVB tester can be modified by fitting a TL-10 UVA compact fluorescence lamp (CFL). To determine whether MPD testing is possible with a CFL and to calculate a fixed factor to convert observed MPD to PUVA-equivalent MPD. Patients had two sets of MPD tests performed on symmetrical, contralateral sites on the lower back. MPD test results from a panel of PUVA lamps were compared with MPD from the modified handheld tester. Additionally, a questionnaire survey was completed by 43 U.K. phototherapy units to assess routine practice concerning MPD testing prior to PUVA therapy. Thirty-seven patients with psoriasis were recruited. Boston phototypes in the 31 with conclusive MPD reactions were: I, four; II, 11; III, 12; and IV, four. The handheld MPD results were linearly related to the PUVA panel MPD results as follows: PUVA MPD = 0·48 × handheld MPD + 0·17 J cm(-2). The measured PUVA MPD was 0·48 of the handheld MPD, not 0·15 as predicted by the published PUVA action spectrum. The modified MPD tester is a convenient and safe method for PUVA MPD testing, overcoming many problems of the 'traditional method'. The difference between the PUVA and TL-10 lamps was lower than predicted from published studies. This suggests that formal re-evaluation of the erythema action spectrum for PUVA is now needed. © 2013 British Association of Dermatologists.

  16. Seeding Cracks Using a Fatigue Tester for Accelerated Gear Tooth Breaking

    Science.gov (United States)

    Nenadic, Nenad G.; Wodenscheck, Joseph A.; Thurston, Michael G.; Lewicki, David G.

    2011-01-01

    This report describes fatigue-induced seeded cracks in spur gears and compares them to cracks created using a more traditional seeding method, notching. Finite element analysis (FEA) compares the effective compliance of a cracked tooth to the effective compliance of a notched tooth where the crack and the notch are of the same depth. In this analysis, cracks are propagated to the desired depth using FRANC2D and effective compliances are computed in ANSYS. A compliance-based feature for detecting cracks on the fatigue tester is described. The initiated cracks are examined using both nondestructive and destructive methods. The destructive examination reveals variability in the shape of crack surfaces.

  17. Identification of rye chromosomes: the Giemsa banding pattern and the translocation tester set.

    Science.gov (United States)

    de Vries, J M; Sybenga, J

    1976-01-01

    The Giemsa banding pattern is given for eleven reciprocal translocations of rye, Secale cereale L., together involving all chromosomes at least once, and one telocentric substitution. It is possible to correlate the identification system based on the Giemsa pattern with that based on the translocation tester set. The location of the translocation break points could be determined very exactly for a number of translocations, somewhat less exactly for others. The variations in the banding pattern, resulting from genetic, environmental and technical variation, make definite identification with the nomenclature system of the different rye additions to wheat difficult. An attempt is made, but some caution is necessary.

  18. Effect of radiant heat and ultrasound on fluoride release and surface hardness of glass ionomer cements.

    Science.gov (United States)

    Tolidis, Kosmas; Dionysopoulos, Dimitrios; Gerasimou, Paris; Sfeikos, Thrasyvoulos

    2016-11-02

    The purpose of this investigation was to evaluate the influence of radiant heat and ultrasound on fluoride release and surface hardness of 3 glass ionomer cements (GICs). There were 3 experimental groups for each GIC; in group 1, the specimens were left to set without any treatment; in group 2, the specimens were irradiated for 2 minutes using a LED unit; and in group 3, ultrasound was applied using a scaler for 55 seconds on the specimen surface. Fluoride release measurements were performed daily for 7 days and at days 14 and 28. Surface hardness of the tested GICs was determined using Vickers method. The measurements were performed 24 hours and 7 days after mixing. Statistical analysis of the data was made using 1-way ANOVA and Tukey's and Bonferroni post hoc tests (α = 0.05). Radiant heat during setting reduced the fluoride release and increased the surface hardness of GICs (p<0.05). Ultrasonic treatment also reduced the fluoride release and increased the surface hardness (p<0.05) of GICs but in lower extent. Among the GICs there were differences in fluoride release and surface hardness properties depending on their composition (p<0.05). Radiant heat and ultrasonic treatments may be useful methods for GIC restorations in order to achieve faster adequate initial mechanical properties.

  19. Hardness of model dental composites - the effect of filler volume fraction and silanation.

    Science.gov (United States)

    McCabe, J F; Wassell, R W

    1999-05-01

    The relationship between structure and mechanical properties for dental composites has often proved difficult to determine due to the use of commercially available materials having a number of differences in composition i.e. different type of resin, different type of filler, etc. This makes a scientific study of any one variable such as filler content difficult if not impossible. In the current study it was the aim to test the hypothesis that hardness measurements of dental composites could be used to monitor the status of the resin-filler interface and to determine the efficacy of any particle silanation process. Ten model composites formulated from a single batch of resin and containing a common type of glass filler were formulated to contain varying amounts of filler. Some materials contained silanated filler, others contained unsilanated filler. Specimens were prepared and stored in water and hardness (Vickers') was determined at 24 h using loads of 50, 100, 200 and 300 g. Composites containing silanated fillers were significantly harder than materials containing unsilanated fillers. For unsilanated products hardness was independent of applied load and in this respect they behaved like homogeneous materials. For composites containing silanated fillers there was a marked increase in measured hardness as applied load was increased. This suggests that the hardness-load profile could be used to monitor the status of the resin-filler interface. Copyright 1999 Kluwer Academic Publishers

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

    Science.gov (United States)

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

    2012-07-01

    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 °C, 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.

  1. Effect of quenching rate on hardness and microstructure of hot-stamped steel

    Energy Technology Data Exchange (ETDEWEB)

    Nishibata, Toshinobu, E-mail: nishibat-tsn@sumitomometals.co.jp [Corporate R and D Labs., Sumitomo Metal Industries Ltd., 1-8 Fuso-Cho, Amagasaki, Hyogo 660-0891 (Japan); Kojima, Nobusato, E-mail: kojima-nbs@sumitomometals.co.jp [Corporate R and D Labs., Sumitomo Metal Industries Ltd., 1-8 Fuso-Cho, Amagasaki, Hyogo 660-0891 (Japan)

    2013-11-15

    Highlights: ► The hot-stamped specimens had an auto-tempered martensite microstructure. ► Below the M{sub s} point, reducing the cooling rate significantly reduces the hardness in the hot-stamped-specimens. ► The major factor that causes the reduction in hardness in hot-stamping is auto-tempering. -- Abstract: The effect of the cooling rate on the hardness and microstructure of the hot-stamped boron steel containing 0.2 mass% carbon was investigated. Sheets with thicknesses of 1.6 and 1.2 mm were heated to 900 °C for 4 min. They were then press formed and simultaneously quench hardened with dies or water quenched. Simulated hot-stamping tests were also performed at various cooling rates. The Vickers hardnesses of the quenched specimens were measured and their cross-sections were observed by optical microscopy and transmission electron microscopy. The hot-stamped specimens had an auto-tempered martensite microstructure and they were softer than the water-quenched specimens, which consisted of lath-martensite. Tempered martensite was distinguished from bainite by observing cementite precipitation. Below the M{sub s} temperature, reducing the cooling rate significantly reduces the hardness, even when the cooling rate is higher than the upper critical cooling rate.

  2. The effect of long-term disinfection procedures on hardness property of resin denture teeth.

    Science.gov (United States)

    Campanha, Nara Hellen; Pavarina, Ana Cláudia; Jorge, Janaina Habib; Vergani, Carlos Eduardo; Machado, Ana Lucia; Giampaolo, Eunice Teresinha

    2012-06-01

    The aim of the study was to evaluate the effect of long-term disinfection procedures on the Vickers hardness (VHN) of acrylic resin denture teeth. Five acrylic resin denture teeth (Vipi Dent Plus-V, Trilux-T, Biolux-B, Postaris-P and Artiplus-A) and one composite resin denture teeth (SR-Orthosit-O) were embedded in heat-polymerised acrylic resin within polyvinylchloride tubes. Specimens were stored in distilled water at 37°C for 48 h. Measurements of hardness were taken after the following disinfection procedures: immersion for 7 days in 4% chlorhexidine gluconate or in 1% sodium hypochlorite (CIm and HIm group, respectively) and seven daily cycles of microwave sterilisation at 650 W for 6 min (MwS group). In the WIm group, specimens were maintained in water during the time used to perform the disinfection procedures (7 days). Data were analysed with anova followed by the Bonferroni procedure (α = 0.01). Microwave disinfection decreased the hardness of all acrylic resin denture teeth (p acrylic resin denture teeth A (p disinfection procedures decrease the hardness of the composite resin denture teeth (p Disinfection procedures changed the hardness of resin denture teeth. © 2011 The Gerodontology Society and John Wiley & Sons A/S.

  3. Evaluation of surface roughness and hardness of different glass ionomer cements

    Science.gov (United States)

    Bala, Oya; Arisu, Hacer Deniz; Yikilgan, Ihsan; Arslan, Seda; Gullu, Abdulkadir

    2012-01-01

    Objectives: The aim of this study was to evaluate surface roughness and hardness of a nanofiller GIC, a resin-modified GIC, three conventional GICs, and a silver-reinforced GIC. Methods: For each material, 11 spcecimens were prepared and then stored in distilled water at 37 °C for 24 h. The surface roughness of 5 specimens was measured using a surface profilometer before polishing and after polishing with coarse, medium, fine, superfine aluminum oxide abrasive Sof-Lex discs respectively. The hardness of the upper surfaces of the remaining 6 specimens was measured with a Vickers microhardness measuring instrument. Results: All tested GICs showed lower surface roughness values after the polishing procedure. Surface finish of nanofiller GIC was smoother than the other tested GICs after polishing. This was followed by resin-modified GIC, Fuji II LC; then silver-reinforced GIC, Argion Molar, conventional GICs, Aqua Ionofil Plus, Fuji IX, and Ionofil Molar, respectively. The result of the hardness test indicated that the microhardness value of silver-reinforced GIC was greater than that of the other GICs. When the hardness values of all tested GICs were compared, the differences between materials (except Aqua Ionofil Plus with Ionofil Molar and Ketac N100 with Fuji II LC (P>.05)) were found statistically significant (P<.05). Conclusions: According to the results of this study, it can be concluded that the differences in the composition of GICs may affect their surface roughness and hardness. PMID:22229011

  4. Analysis of the relationship between the surface hardness and wear resistance of indirect composites used as veneer materials.

    Science.gov (United States)

    Faria, Adriana Cláudia Lapria; Benassi, Ubiratan Menezes; Rodrigues, Renata Cristina Silveira; Ribeiro, Ricardo Faria; Mattos, Maria da Gloria Chiarello de

    2007-01-01

    This study evaluated the surface hardness and wear resistance of indirect composites (Artglass and Solidex) and the existence of a correlation between these properties. Twenty-four specimens (12 per material) were fabricated using a polytetrafluoroethylene matrix (5.0 mm in diameter; 7.0 mm high) following an incremental technique. Polymerization was done with a xenon stroboscopic light curing unit. After polishing, the specimens were stored in water at 37 degrees C during either 1 day (n=6 per material) or 55 days (n=6 per material), after which Vickers surface hardness and wear resistance were assessed. Data were analyzed statistically by unpaired Student t-test, two-way ANOVA and Tukey's test. SURFACE HARDNESS: Artglass had higher surface hardness than Solidex after 1-day immersion period (pmaterials (p>0.05). Comparing the materials at both periods, Artglass means differed significantly to each other (p0.05). WEAR RESISTANCE: Solidex had higher wear than Artglass after 1-day immersion period (pmaterials after 55 days (p>0.05). Comparing the materials at both periods, Artglass means differed significantly to each other (p0.05). These results suggest that Artglass was better than Solidex in terms of hardness and wear resistance after 1-day water immersion. However, it was more susceptible to degradation, showing greater wear after 55 days. In conclusion, there was an inverse correlation between surface hardness and wear resistance for both Artglass and Solidex indirect composites, that is the higher the hardness, the lower the wear.

  5. Ablation of human carious dentin with a nanosecond pulsed laser at a wavelength of 5.85 μm: relationship between hardness and ablation depth

    Science.gov (United States)

    Ishii, Katsunori; Kita, Tetsuya; Yoshikawa, Kazushi; Yasuo, Kenzo; Yamamoto, Kazuyo; Awazu, Kunio

    2014-02-01

    Less invasive treatment and preservation of teeth, referred to as minimal intervention, are strong requirements in dentistry. In our previous study, the fundamental ablation properties of human dentin at wavelengths around 5.8 μm were investigated, and the results indicated that the wavelength of 5.85 μm was optimal for selective removal of carious dentin with less damage to normal dentin. The purpose of this study was to investigate the relationship between the ablation depth and hardness of human dentin including carious lesion. A nanosecond pulsed laser produced by difference-frequency generation was used for irradiations to human carious dentin. It was observed that correlation between ablation depth and Vickers hardness after 2 s laser irradiation at the wavelength of 5.85 μm and the average power density of 30 W/cm2. On the other hand, ablations did not depend on Vickers hardness at the wavelength of 6.00 μm. A nanosecond pulsed laser with the wavelength at 5.85 μm is useful for selective ablation of human carious dentin in accordance with the hardness.

  6. Combining Ability in Wheat for Seedling Traits by Line X Tester Analysis Under Saline Conditions

    Directory of Open Access Journals (Sweden)

    Muhammad Osaf

    Full Text Available A line × tester analysis involving five varieties SQ-26, SQ-77, GH-10, 8670, PARC-N2 (lines and three varieties 8721, SARC-5 and DN-4 (testers were crossed to study some hydroponics growing characters. In controlled conditions SQ-26 exhibited the highest positive GCA effects on Shoot length, Shoot fresh weight, Na+ and K+ concentrations, while SQ-77 showed maximum GCA effects on Root length, Root fresh weight and Shoot dry weight in females and in males and both DN-4 and SARC-5 showed the highest GCA effects. Under high saline concentration female SQ-77 showed the maximum positive effects on all characters but on shoot length and Na concentration while male SARC-5 exhibited the highest positive GCA effects on all characters. Under high saline level, the cross combination SQ-26 × 8721 showed SCA effects for shoot length, whereas 8670 x 8721 showed the same effects for shoot fresh weight, root fresh weight and root dry weight. For Na+ and K+ concentrations, the cross combination GH-10 × DN-4 showed then highest SCA effects, whereas for shoot dry weight and root length, the cross combinations GH-10 × SARC-5 and PARC-N2 × 8721 showed the highest SCA effects, respectively.

  7. A low-volume tester for the thrombogenic potential of mechanical heart valve prostheses.

    Science.gov (United States)

    Linde, Torsten; Hamilton, Kathrin F; Timms, Daniel L; Schmitz-Rode, Thomas; Steinseifer, Ulrich

    2011-09-01

    During the development of a mechanical heart valve prosthesis, many studies are conducted to guarantee its correct function. Currently, investigations into the thrombogenic potential of a valve after its replacement are conducted with expensive and time-consuming chronic animal trials. Hence, the study aim was to develop and test an alternative system to resolve such thrombogenic issues. The Thrombosis Tester of the Helmholtz Institute Aachen (THIA II) has a reasonably small priming volume (220-270 ml) that allows analysis of the thrombogenic potential of two valves, using one human blood bottle. Hydrodynamic evaluation demonstrated an absolutely stable physiological pressure and flow progression at the aortic and pulmonary positions. A sinus geometry of the human aortic root is implemented downstream of the valve in order to guarantee physiological leaflet motion. The tester remained absolutely thrombus-free during several tests carried out with minimally anticoagulated porcine blood, while the valves showed reproducible thrombus formation in reasonable locations. Tests with fully heparinized porcine blood showed that a soft silicon fixture for the valve could reduce hemolysis in the THIA II. This in-vitro test protocol can enable the optimization of a valve design during the early stages of its research and development. The system can provide a unique and suitable supplement to animal trials for testing thrombogenic performance, under constant and reproducible boundary conditions, including considerable physiological and pathological circumstances such as the influence of valve position (aortic, pulmonic), and a comparison of different valve types.

  8. [Design of the psychology tester based on ZigBee technology].

    Science.gov (United States)

    Zhong, Tianping; Tang, Liming

    2012-09-01

    To design a psychological state tester based on ZigBee wireless technology. Through analog circuit preprocessing, the heartbeat collected by the pulse sensor will be transformed into digital signal from analog signal, and then can be processed and displayed after transported to the personal computer through the Zigbee wireless communicate units. The data will be retrieval and playback for the measurement of psychology. The experiments show that the device is able to acquire the pulse wave of the human body in real-time, at the same time, through the ZigBee wireless network, it can accomplish real-time, secure and reliable communications, and it also can be used in the research of testing the mental state of the individual. Through the application of the ZigBee communicate technology; the psychology tester can collect the pulse signal to reflect the individual's mental state in different conditions. So it will be applicable to a wide range of psychology measurement and other areas.

  9. Inter-tester reproducibility of tumour change in small cell lung cancer patients undergoing chemoradiotherapy.

    Science.gov (United States)

    Ellegaard, Mai-Britt Bjørklund; Knap, Marianne Marquard; Hoffmann, Lone

    2013-10-01

    Tumour volume change during delivery of chemoradiotherapy is observed in small cell lung cancer (SCLC) patients. In this study, we have compared tumour volume and anatomical changes, e.g. atelectasis or pleural effusions determined by three different methods. A total of 37 SCLC patients undergoing thoracic radiotherapy during 2010-2011 were included. The patients were treated based on a daily three-dimensional (3D) cone beam computed tomography (CBCT) bony anatomy registration. The CBCT scans were retrospectively reviewed visually by a radiation therapist (Visual-RTT) in order to register tumour volume changes. Furthermore, the tumour volume changes were obtained by either deformable image registration (DIR) or delineation by a radiation oncologist (RO). Kappa (κ) statistics and paired t-tests were used for evaluation of the inter-tester agreement. The tumour volume change between the Visual-RTT, the DIR and the RO assessments obtained 84-97% agreement (κ = 0.68-0.95). Furthermore, there was no statistically significant difference between the tumour change assessment of the RO (mean 13.6 ml) and the DIR (mean 14.5 ml), p = 0.59. Tumour shrinkage was observed in 15 (41%) patients and anatomical changes in seven (19%) patients. The inter-tester reproducibility of tumour volume change between the three methods is excellent. Visual-RTT on-line inspection may be used to determine tumour shrinkage and anatomical changes as atelectasis or pleural effusions during the radiotherapy course by use of daily CBCT scans.

  10. Interference of apex locator, pulp tester and diathermy on pacemaker function.

    Science.gov (United States)

    Sriman, Narayanan; Prabhakar, V; Bhuvaneswaran, J S; Subha, N

    2015-01-01

    The purpose of this study was to evaluate the effects of three electronic apex locators (EAL), electric pulp tester (EPT) and diathermy on pacemaker function in vitro. Three EALs: Root ZX (J. Morita Co., Tustin, CA, U.S.A.), Propex (Dentsply), Mini Apex locator (SybronEndo, Anaheim, CA, USA), EPT (Parkell pulp vitality tester Farmingdale, NY, USA) and Diathermy (Neomed 250 B) were tested for any interference with one pacemaker (A medtronic kappa KVDD901-serial number: PLE734632S). Directly connecting the pacemaker lead with the EAL/EPT/diathermy operating on a flat bench top, the telemetry wand was held directly over the pacemaker to monitor the pacing pattern for a period of 30 s. Pacemaker activity was continuously recorded on the telemetric programmer and electro gram (EGM) readings examined for pacer inhibition, noise reversion or inappropriate pacemaker pulses. All the three apex locators showed no pacing interference or background noise during its function or at rest. The EGM readings of EPT showed varying levels of background noise in between pacing however, this did not affect the normal pacing pattern and the pacing interval remained constant. EGM readings of diathermy showed an increase in the pacing interval (irregular pacing pattern) followed by complete inhibition of the pacing system. The tested EALs do not interfere with cardiac pacemaker function. The tested EPT showed varying levels of background noise but does not interfere with cardiac pacemaker function. Use of Diathermy interfered with the normal pacing, leading to complete inhibition of the pacing system.

  11. Development of a tester for evaluation of prototype thermal cells and batteries

    Science.gov (United States)

    Guidotti, Ronald A.

    A tester was developed to evaluate prototype thermal cells and batteries--especially high-voltage units--under a wide range of constant-current and constant-resistance discharge conditions. Programming of the steady-state and pulsing conditions was by software control or by hardware control via an external pulse generator. The tester was assembled from primarily Hewlett-Packard (H-P) instrumentation and was operated under H-P's Rocky Mountain Basic (RMB). Constant-current electronic loads rated up to 4 kW (400 V at up to 100 A) were successfully used with the setup. For testing under constant-resistance conditions, power metal-oxide field-effect transistors (MOSFET's) controlled by a programmable pulse generator were used to switch between steady-state and pulse loads. The pulses were digitized at up to a 50 kHz rate (20 microseconds/pt) using high-speed DVM's; steady-state voltages were monitored with standard DVM's. This paper describes several of the test configurations used and discusses the limitations of each. Representative data are presented for a number of the test conditions.

  12. From Playroom to Lab: Tough Stretchable Electronics Analyzed with a Tabletop Tensile Tester Made from Toy-Bricks.

    Science.gov (United States)

    Moser, Richard; Kettlgruber, Gerald; Siket, Christian M; Drack, Michael; Graz, Ingrid M; Cakmak, Umut; Major, Zoltan; Kaltenbrunner, Martin; Bauer, Siegfried

    2016-04-01

    Toy bricks are an ideal platform for the cost-effective rapid prototyping of a tabletop tensile tester with measurement accuracy on par with expensive, commercially available laboratory equipment. Here, a tester is presented that is not only a versatile demonstration device in mechanics, electronics, and physics education and an eye-catcher on exhibitions, but also a powerful tool for stretchable electronics research. Following the "open-source movement" the build-up of the tester is described and all the details for easy reproduction are disclosed. A a new design of highly conformable all-elastomer based graded rigid island printed circuit boards is developed. Tough bonded to this elastomer substrate are imperceptible electronic foils bearing conductors and off-the-shelf microelectronics, paving the way for next generation smart electronic appliances.

  13. From Playroom to Lab: Tough Stretchable Electronics Analyzed with a Tabletop Tensile Tester Made from Toy‐Bricks

    Science.gov (United States)

    Kettlgruber, Gerald; Siket, Christian M.; Drack, Michael; Graz, Ingrid M.; Cakmak, Umut; Major, Zoltan; Kaltenbrunner, Martin; Bauer, Siegfried

    2016-01-01

    Toy bricks are an ideal platform for the cost‐effective rapid prototyping of a tabletop tensile tester with measurement accuracy on par with expensive, commercially available laboratory equipment. Here, a tester is presented that is not only a versatile demonstration device in mechanics, electronics, and physics education and an eye‐catcher on exhibitions, but also a powerful tool for stretchable electronics research. Following the “open‐source movement” the build‐up of the tester is described and all the details for easy reproduction are disclosed. A a new design of highly conformable all‐elastomer based graded rigid island printed circuit boards is developed. Tough bonded to this elastomer substrate are imperceptible electronic foils bearing conductors and off‐the‐shelf microelectronics, paving the way for next generation smart electronic appliances. PMID:27588259

  14. Hardness as a modification index for malting red and white sorghum (kaffir) grains.

    Science.gov (United States)

    Uvere, Peter O; Ngoddy, Patrick O; Nwankwo, Chibuzo S

    2014-03-30

    This study investigated changes in the resistance to fracture of malting red and white sorghum grains using a hardness tester as another method for monitoring grain modification. Grain hardness decreased progressively from 134.35 N and 137.29 N in malting red and white sorghums and levelled off after 120 h at 76.98 N and 69.14 N. In the red grain malts traditionally used for burukutu production, moisture content (r = -0.983), dhurrinase activity (r = -0.981), malting loss (r = -0.981), free amino nitrogen (r = -0.909) and cold water extract (r = -0.908) were better indicators of grain hardness than root length (r = -0.89). In the white sorghum malts, malting loss (r = -0.988), dhurrinase activity (r = -0.954) and diastatic activity (r = -0.936) were better indicators of grain modification than root length (r = -0.916). The soluble nitrogen ratio at the end of malting was lower in the red (0.049) compared with the white (0.0548). Grain hardness using a hand-held tester is a simple, fast and good index of modification of malting red and white sorghum grains. Oven-dried red and white sorghum malts could be considered to be well modified at hardness values/indices below 77 N/0.5730 and 72 N/0.5036, respectively. © 2013 Society of Chemical Industry.

  15. Session: Hard Rock Penetration

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-01-01

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

  16. Hard-hat day

    CERN Multimedia

    2003-01-01

    CERN will be organizing a special information day on Friday, 27th June, designed to promote the wearing of hard hats and ensure that they are worn correctly. A new prevention campaign will also be launched.The event will take place in the hall of the Main Building from 11.30 a.m. to 2.00 p.m., when you will be able to come and try on various models of hard hat, including some of the very latest innovative designs, ask questions and pass on any comments and suggestions.

  17. Hip strength assessment using handheld dynamometry is subject to intertester bias when testers are of different sex and strength

    DEFF Research Database (Denmark)

    Thorborg, K; Bandholm, T; Schick, M

    2013-01-01

    of this study was to examine the intertester reliability concerning strength assessments of hip abduction, adduction, external and internal rotation, flexion and extension using HHD, and to test whether systematic differences in test values exist between testers of different upper-extremity strength. Fifty...... healthy individuals (29 women), aged 25 ± 5 years were included. Two physiotherapist students (one female, one male) of different upper-extremity strength performed the measurements. The tester order and strength test order were randomized. Intraclass correlation coefficients were used to quantify...

  18. The difference nanocomposite hardness level using LED photoactivation based on curing period variations

    Directory of Open Access Journals (Sweden)

    Hasiana Tatian

    2011-03-01

    Full Text Available Polimerizatian is the critical stage to determine the quality of composites resin, this involves isolated monomer carbon double bonds being converted to an extended network of single bonds. Physical and mechanical properties of composites are influenced by the level of conversion attained during polymerization. An adequate light intensity and light curing time are important to obtain the degree of polymerization. The objective of this study is to evaluate the difference of the hardness nanocomposites which activated by LED LCU based on the variation of curing times. This study is a true experimental research. The samples were made from nanocomposites material with cylinder form of 4 mm in depth, 6 mm in diameter. This samples divided into 3 groups of curing times. Group, I was cured for 20's curing time as a control due to manufactory recommended; Group II was cured for 30's, and Group III was cured for 40's and the hardness (Rebound hardness tester was determined using Rebound scale (RS and converted by Mohs scale (MS. There was a very significant level of hardness rate from each group using ANOVA test. The result of the study concludes that there were the differences on the nanocomposites hardness level cured under different curing times 20, 30 and 40 sec. The longer of curing times, the higher level of hardness.

  19. Effect of ethanol in mouthwashes on the surface hardness of a dental resin composite material

    Directory of Open Access Journals (Sweden)

    Decky J. Indrani

    2009-03-01

    Full Text Available The previous study has shown that dental resins exhibited changes in the surface hardness when soaked in alcoholic beverages. As ethanol was one of the components contained in some commercial mouthwashes, therefore, the present study aimed at the effect of ethanol in some mouthwashes on the surface hardness of a dental resin composite. Specimens were prepared from a light cured dental resin composite. The specimens were then immersed in some commercial mouthwashes for periods up to 14 days. The surface hardness of the specimens was then measured using a Microhardness tester. The results displayed reductions in surface hardness (p<0,01, upon one day of immersing the specimens in Bactidol®, Listerine® or Minosepe® mouthwash, respectively. The surface hardness curves from each mouthwash demonstrated a similar pattern which approached a plateau near 2 weeks. It can be concluded that the ethanol-containing mouthwashes appeared to have more implication on surface hardness of the dental resin composite and the effect of immersing in the mouthwashes was time-dependent; it decreased sharply on the first day of immersion, however, further changes, did not exist.

  20. Hardness and excitation energy

    Indian Academy of Sciences (India)

    It is shown that the first excitation energy can be given by the Kohn-Sham hardness (i.e. the energy difference of the ground-state lowest unoccupied and highest occupied levels) plus an extra term coming from the partial derivative of the ensemble exchange-correlation energy with respect to the weighting factor in the ...

  1. Hard Probes at ATLAS

    CERN Document Server

    Citron, Z; The ATLAS collaboration

    2014-01-01

    The ATLAS collaboration has measured several hard probe observables in Pb+Pb and p+Pb collisions at the LHC. These measurements include jets which show modification in the hot dense medium of heavy ion collisions as well as color neutral electro-weak bosons. Together, they elucidate the nature of heavy ion collisions.

  2. Hardness of metallic crystals

    Indian Academy of Sciences (India)

    Administrator

    where H is the hardness, k the coefficient, G the shear modulus, ν the Poisson's ratio, η a function of the radius of an atom (r) and the electron density at the atom interface (n). The formula will not only be used to testify the critical grain size with stable dislocations, but also play an important role in the understanding of ...

  3. Running in Hard Times

    Science.gov (United States)

    Berry, John N., III

    2009-01-01

    Roberta Stevens and Kent Oliver are campaigning hard for the presidency of the American Library Association (ALA). Stevens is outreach projects and partnerships officer at the Library of Congress. Oliver is executive director of the Stark County District Library in Canton, Ohio. They have debated, discussed, and posted web sites, Facebook pages,…

  4. CSI: Hard Drive

    Science.gov (United States)

    Sturgeon, Julie

    2008-01-01

    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.…

  5. Hard and Soft Governance

    DEFF Research Database (Denmark)

    Moos, Lejf

    2009-01-01

    The governance and leadership at transnational, national and school level seem to be converging into a number of isomorphic forms as we see a tendency towards substituting 'hard' forms of governance, that are legally binding, with 'soft' forms based on persuasion and advice. This article analyses...

  6. Hardness and excitation energy

    Indian Academy of Sciences (India)

    Unknown

    form a new species leading to a single electronegativity or chemical potential (the same way as in ordinary thermodynamics). The hardness η of an electronic system is ..... Technological Innovation Foundation and the Minis- try of Science and Technology. This work was also supported by the grant OTKA No. T042505.

  7. The analysis of effect of heat treatment temperature on micro structure, crystal structure and hardness material on alloy Zr 96,2 Sn 2,3Nb1.1 Fe0,4

    Science.gov (United States)

    Saing, Bungaran; Budiarto

    2017-09-01

    The effect of heat treatment temperature (in 500 0C, 600 0C, and 700 0C) from Zr 96,2 Sn 2,3Nb1.1 Fe0,4 as fuel cladding material candidate’s reactor nuclear power plant; for microstructure, crystal structure, and hardness has been carried out. Several characteristic was conducted by using an optical microscope, x-ray diffractometer and Vickers method. The result showed the crystalline characteristic peaks by a tendency to a single crystal formation and microstructure is getting better with less precipitation and the hardness of the alloy is 329.6 4.5 HVN after the homogenization process.

  8. Influence of ion-irradiation on hardness change in type 304 stainless steel weldment containing delta({delta}) ferrite

    Energy Technology Data Exchange (ETDEWEB)

    Chi, Se-Hwan; Kim, Gen-Chan; Hong, Jun-Hwa [Korea Atomic Energy Research Institute, Nuclear Materials Development Team, Taejon (Korea); Shin, Yong-Kwan [Hyundai Power Tech., Transmission Production Team, Chungnam (Korea); Kim, Young-Jig [Sungkyunkwan Univ., Dept. of Advanced Materials Engineering, Kyonggi-do (Korea)

    2002-04-01

    Differences of high energy-ion induced microstructure of bcc {delta}-ferrite and fcc austenite matrix, and the effects of {delta}-ferrite on the Vickers micro-hardness (Hv) after irradiation were investigated for Type 304 stainless steel weldments containing two different {delta}-ferrite contents: ferrite number (FN) 5.5 and 8.5, respectively. Specimens were irradiated to 1.5 dpa with 8 MeV Fe{sup +4} ions using a Tandem Vande-Graff accelerator (flux: 4.3 x 10{sup 10} ion/cm{sup 2}{center_dot}s, fluence: 0.83 x 10{sup 15} ion/cm{sup 2}) at below 60 degC. Calculations TRIM 95 showed that a peak damage appeared at 1.5 {mu}m in depth with 0.7 {mu}m full width at half maximum (FWHM). These results on irradiation-induced defects (IIDs) distribution were confirmed by TEM. Clear differences for the size and number density of IIDs as black dots (size: 5-10 nm) and loops observed in both the austenitic matrix and {delta}-ferrite, where the size of IIDs was far larger in the fcc matrix than the bcc {delta}-ferrite. Hv test results showed that the irradiation hardening of {delta}-ferrite was about 1.5 times larger than the austenitic matrix. From microstructural observation the increase of the higher Vickers micro-hardness was explained. (author)

  9. Evaluation of the Hamburg Rut Tester and Moisture Induced Stress Test (MIST) for field control of hot mix asphalt (HMA) in Oklahoma : final report.

    Science.gov (United States)

    2013-03-01

    This report covers the evaluation of the Hamburg Loaded Wheel Rut Tester (OHD L-55) and the : Moisture Induced Stress Tester (MIST) for field control of Oklahoma HMA mixtures. OHD L-55 : was evaluated as a possible replacement for AASHTO T 283 and fo...

  10. An in vitro investigation of wear resistance and hardness of composite resins.

    Science.gov (United States)

    Cao, Liqun; Zhao, Xinyi; Gong, Xu; Zhao, Shouliang

    2013-01-01

    The aim of the present study was to investigate the wear resistance and hardness of five kinds of composite resins. Sixty-five specimens were fabricated with one nano-hybrid (Charisma Diamond), two micro-hybrid (3MZ250, Clearfil AP-X) and two packable (3MP60, Surefil) composite resins, according to a randomized complete block design (n=13, 8 for wear test; 5 for hardness test). The composites were filled in a rectangular mold, and light polymerization. After storage in 37°C deionized water for 24h, all specimens were tested with a custom-made toothbrush machine with a stainless-steel ball as antagonist (3N loads, 1Hz, 6×10(5) cycles) immersed in calcium fluoride slurry. Wear volume, hardness and surface structure of each tested material was examined by a three-dimensional non-contact optical profilometer, Vickers indentation technique and scanning electron microscope. The volume loss ranked from least to most as follows: Charisma Diamond, P60, Z250, Clearfil AP-X and Surefil. Regarding hardness, the rank from highest to lowest as follows: Clearfil AP-X, P60, Surefil, Z250, Charisma Diamond. The interactions between wear resistance and microhardness were not significant. The custom-made machine is considered suitable to simulate sliding of an antagonist cusp on an opposing occlusal composite restoration. Nanofilled composite may have superior wear compared to other composite resins.

  11. Hardness changes and substructural degradation during creep of a Mod.9Cr-1Mo steel

    Energy Technology Data Exchange (ETDEWEB)

    Endo, T.; Park, K.S. [Yokohama National Univ. (Japan). Dept. of Materials Engineering; Masuyama, F. [Mitsubishi Heavy Industries Ltd. (Japan). Nagasaki Research and Development Center

    2002-07-01

    In order to investigate the structural degradation during creep, interrupted creep tests were conducted of a Mod.9Cr-1Mo steel in the range of stress and temperature from 71 to 167 MPa and 873 to 923 K. The change of hardness and tempered martensitic lath width were measured in grip and gauge parts of interrupted specimens. The lath structure was thermally stable in static conditions, however, it was not stable during creep and the structural change was enhanced by creep strain. The relation between the change in lath width and strain was described quantitatively. The change in Vickers hardness was expressed by a single valued function of creep life consumption ratio. Based on the empirical relation between strain and lath width, a model was proposed to describe the relation between change in hardness and creep life consumption ratio. The comparison of the model with the empirical relation suggests that about 65% of hardness loss is due to the decrease of dislocation density accompanied by the movement of lath boundaries. The role of precipitates on subboundaries was discussed in connection with the abnormal subgrain growth appearing in low stress regime. (orig.)

  12. Effects of the bleaching procedures on enamel micro-hardness: Plasma Arc and diode laser comparison.

    Science.gov (United States)

    Nematianaraki, Saeid; Fekrazad, Reza; Naghibi, Nasim; Kalhori, Katayoun Am; Junior, Aldo Brugnera

    2015-10-02

    One of the major side effects of vital bleaching is the reduction of enamel micro-hardness. The purpose of this study was to evaluate the influence of two different bleaching systems, Plasma Arc and GaAlAs laser, on the enamel micro-hardness. 15 freshly extracted human third molars were sectioned to prepare 30 enamel blocks (5×5 mm). These samples were then randomly divided into 2 groups of 15 each (n=15): a plasma arc bleaching group (: 350-700 nm) + 35% Hydrogen Peroxide whitening gel and a laser bleaching group (GaAlAs laser, λ: 810 nm, P: 10 W, CW, Special Tip) + 35% Hydrogen Peroxide whitening gel. Samples were subjected to the Vickers micro-hardness test (VHN) at a load of 50 g for 15s before and after treatment. Data were statistically analyzed by a Mann-Whitney test (p≤0.05). In the GaAlAs laser group, the enamel micro-hardness was 618.2 before and was reduced to 544.6 after bleaching procedures. In the plasma arc group, the enamel micro-hardness was 644.8 before and 498.9 after bleaching. Although both techniques significantly reduced VHN, plasma arc bleaching resulted in a 22.62% reduction in VHN for enamel micro-hardness, whereas an 11.89% reduction in VHN was observed for laser bleaching; this difference is statistically significant (pplasma arc. Therefore GaAlAs laser bleaching has fewer harmful effects than plasma arc in respect to enamel micro-hardness reduction.

  13. Determination of the penetration hardness and analysis of stainless steel alloys by means of Laser Induced Breakdown Spectroscopy (LIBS

    Directory of Open Access Journals (Sweden)

    mohamad Vahid Dastjerdi

    2017-11-01

    Full Text Available A significant feature of alloys is the surfaces hardness that is always accompanied by challenges when it’s measured by common mechanical techniques. In this investigation, we used Laser Induced Breakdown Spectroscopy (LIBS as a replacement method for common mechanical techniques to measure the surfaces hardness of different alloys. After recording the spectrum of alloy samples in order to identify the surface hardness of analyzed sample, K-Nearest Neighbors method (KNN was used and obtained results showed that the LIBS-KNN method can separate and identify the surfaces hardness of samples with precision of 93.3%. In addition, in order to identify the percentage of constituent elements of alloys and their hardness, calibration approach was investigated that showed there is an appropriate linear relation between recorded emission lines from the LIB spectra of sample alloys and the percentage of their constituent elements and also their Vickers hardness numbers. Therefore, According to exclusive advantages of LIBS technique i.e. high speed analysis, non-destructive analysis and being portable, some of available difficulties in conventional mechanical techniques can be removed.

  14. Effect of conventional and sugar free pediatric syrup formulations on primary tooth enamel hardness: An in vitro study.

    Science.gov (United States)

    Mali, Gaurao Vasant; Dodamani, Arun Suresh; Karibasappa, Gundabaktha Nagappa; Kumar, Prashanth Vishwakarma; Jain, Vardhaman Mulchand

    2015-01-01

    To assess and compare the effect of conventional and sugar free pediatric syrup formulations on primary tooth enamel hardness over a period of 14 days. An in vitro study was done on 40 noncarious deciduous teeth. 10 teeth in each group were dipped in 4 pediatric medicinal syrups (1 sugarfree and 3 conventional) for 1 min thrice daily for 14 days and the enamel surface micro hardness was checked at baseline, 7 th day and 14 th day by Vickers hardness testing machine. The pH, titratable acidity and buffering capacity of the syrups were assessed. The pH of syrups were above critical pH for demineralization of the tooth but tiratable acidity and buffering capacity differed. ANOVA test indicated that the reduction in mean micro hardness was maximum in Group D (Conventional Analgesic syrup) and least in Group A (Sugarfree cough syrup) on 7 th and 14 th day. On intergroup comparison there was no difference (P > 0.05) in micro hardness between Group B (Conventional Cough syrup) and Group C (Conventional Antibiotic). However, highly significant (P hardness on 14 th day was maximum for Group D (24.4 ± 2.2) and minimum for Group A (14.0 ± 1.3) which was statistically significant (P < 0.01). Sugar free pediatric medicines can be effective in reducing dental erosion and efforts should be made to incorporate sugar substitutes in formulation of pediatric medicines.

  15. Hardness and surface roughness of enamel and base layers of resin denture teeth after long-term repeated chemical disinfection.

    Science.gov (United States)

    Neppelenbroek, Karin Hermana; Kurokawa, Luciana Ayumi; Procópio, Andréa Lemos Falcão; Pegoraro, Thiago Amadei; Hotta, Juliana; Mello Lima, Jozely Francisca; Urban, Vanessa Migliorini

    2015-01-01

    To evaluate the effect of successive cycles of disinfection in different denture cleansers on the surface roughness and the Vickers hardness of two layers of acrylic resin (base-BL and enamel-EL) of two commercial cross-linked artificial teeth. The occlusal surfaces of 60 acrylic resin denture posterior teeth (Trilux-TLX and SR Orthosit PE-SRO) embedded in autopolymerizing acrylic resin were ground fat with 1200-grit silicon carbide paper. Specimens were stored in distilled water at 37°C and then submitted to the microhardness (VHN) and roughness (μm) tests. Specimens were stored in distilled water at 37°C for 90 days and submitted to 720 disinfection cycles in sodium hypochlorite at 0.5%, 30% vinegar solution or distilled water (control). Afterward, micro-hardness and roughness tests were again performed. Data were analyzed using two-way ANOVA and Tukey's test (α=0.05). Hypochlorite immersion decreased the hardness of BL and EL of SRO teeth, with an average reduction of 10.11% (p0.37). Hypochlorite promoted deleterious effects on the hardness of both layers of the artificial teeth tested. Immersion in vinegar and water also resulted in reduction of hardness of TLX teeth. The surface hardness of the different layers of cross-linked artificial teeth can be altered by daily disinfection in denture cleansers commonly indicated for removable dentures.

  16. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHN V. VICKERS in the Bering Sea, North Pacific Ocean and South Pacific Ocean from 1992-08-16 to 1992-10-21 (NODC Accession 0115003)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115003 includes chemical, discrete sample, physical and profile data collected from JOHN V. VICKERS in the Bering Sea, North Pacific Ocean and South...

  17. Magnetic properties measurement of soft magnetic composite material (SOMALOY 700) by using 3-D tester

    Science.gov (United States)

    Asari, Ashraf; Guo, Youguang; Zhu, Jianguo

    2017-08-01

    Core losses of rotating electrical machine can be predicted by identifying the magnetic properties of the magnetic material. The magnetic properties should be properly measured since there are some variations of vector flux density in the rotating machine. In this paper, the SOMALOY 700 material has been measured under x, y and z- axes flux density penetration by using the 3-D tester. The calibrated sensing coils are used in detecting the flux densities which have been generated by the Labview software. The measured sensing voltages are used in obtaining the magnetic properties of the sample such as magnetic flux density B, magnetic field strength H, hysteresis loop which can be used to calculate the total core loss of the sample. The results of the measurement are analyzed by using the Mathcad software before being compared to another material.

  18. Automated Coverage Tester for the Oracle Archiver of WinCC OA

    CERN Document Server

    Voitier, A; Gonzalez-Berges, M

    2011-01-01

    A large number of control systems at CERN are built with the commercial SCADA tool WinCC OA (formerly PVSS) [1]. They cover projects in the experiments, accelerators and infrastructure. An important component is the Oracle archiver used for long term storage of process data (events) and alarms. The archived data provide feedback to the operators and experts about how the system was behaving at particular moment in the past. In addition a subset of these data is used for offline physics analysis (conditions data). Large volumes of data are produced by the different facilities at CERN (several Terabytes per year). The consistency of the archived data has to be ensured from writing to reading as well as throughout updates of the control systems. The complexity of the archiving subsystem comes from the multiplicity of data types, required performance and other factors such as operating system, environment variables or versions of the different software components. Therefore an automatic tester has been implemente...

  19. Analysis of Material Sample Heated by Impinging Hot Hydrogen Jet in a Non-Nuclear Tester

    Science.gov (United States)

    Wang, Ten-See; Foote, John; Litchford, Ron

    2006-01-01

    A computational conjugate heat transfer methodology was developed and anchored with data obtained from a hot-hydrogen jet heated, non-nuclear materials tester, as a first step towards developing an efficient and accurate multiphysics, thermo-fluid computational methodology to predict environments for hypothetical solid-core, nuclear thermal engine thrust chamber. The computational methodology is based on a multidimensional, finite-volume, turbulent, chemically reacting, thermally radiating, unstructured-grid, and pressure-based formulation. The multiphysics invoked in this study include hydrogen dissociation kinetics and thermodynamics, turbulent flow, convective and thermal radiative, and conjugate heat transfers. Predicted hot hydrogen jet and material surface temperatures were compared with those of measurement. Predicted solid temperatures were compared with those obtained with a standard heat transfer code. The interrogation of physics revealed that reactions of hydrogen dissociation and recombination are highly correlated with local temperature and are necessary for accurate prediction of the hot-hydrogen jet temperature.

  20. Inter- and intra-tester reliability of sensibility testing in digital nerve repair.

    Science.gov (United States)

    Bulut, T; Akgun, U; Ozcan, C; Unver, B; Sener, M

    2016-07-01

    The aim of this study was to investigate the inter- and intra-tester reliability of the static two-point discrimination and Semmes-Weinstein monofilament tests in digital nerve repair. A total of 100 digital nerves from 67 patients were included into the study. An experienced orthopaedic surgeon and a physiotherapist examined the sensory nerve recovery. The reproducibility score of both tests was at a poor level, but the reliability of the Semmes-Weinstein monofilament test was higher than the static two-point discrimination test. These tests should not be used alone in the quantitative monitoring of sensory recovery, but should be interpreted with the clinical findings.Level 3 non-randomized controlled study. © The Author(s) 2015.

  1. Glitch Game Testers: The Design and Study of a Learning Environment for Computational Production with Young African American Males

    Science.gov (United States)

    DiSalvo, Elizabeth Betsy

    2012-01-01

    The implementation of a learning environment for young African American males, called the Glitch Game Testers, was launched in 2009. The development of this program was based on formative work that looked at the contrasting use of digital games between young African American males and individuals who chose to become computer science majors.…

  2. Inter- and intra-tester reliability of the acute brain injury physiotherapy assessment (ABIPA) in patients with acquired brain injury.

    Science.gov (United States)

    Gesch, Janelle M; Low Choy, Nancy L; Weeks, Benjamin K; Nascimento, Margarida; Steele, Michael; Kuys, Suzanne S

    2017-01-01

    The Acute Brain Injury Physiotherapy Assessment (ABIPA) is a new outcome measure with face validity and sensitivity to change in the early stages of neuromotor recovery after acquired brain injury (ABI). Reliability of physiotherapists using the tool has not been established. Determine inter- and intra-tester reliability of physiotherapists using the ABIPA. An observational study using video-recorded assessments of patient performance (n = 7) was undertaken with two cohorts of physiotherapists: those receiving training (n = 23) and those provided with guidelines only (n = 7) to administer the ABIPA. Across all physiotherapists (n = 30), inter-tester reliability was excellent (α ≥ 0.9) for total ABIPA score. All individual items, except trunk alignment in supine (α = 0.5), showed excellent or good internal consistency (α ≥ 0.7). For intra-tester reliability, substantial or perfect agreement was achieved for eight items (weighted Kappa Kw ≥ 0.6), moderate agreement for four items (Kw = 0.4-0.6) and three items achieved fair agreement (alignment head supine: Kw = 0.289; alignment trunk supine: Kw = 0.387 and tone left upper limb: Kw = 0.366). Physiotherapists are highly consistent using the ABIPA but several items may need revision to improve intra-tester reliability.

  3. Evaluation of a New Controlled Point Source LED Glare Tester for Disability Glare Detection in Participants With and Without Cataracts.

    Science.gov (United States)

    Epitropoulos, Alice T; Fram, Nicole R; Masket, Samuel; Price, Francis W; Snyder, Michael E; Stulting, R Doyle

    2015-03-01

    To determine glare-induced change during visual acuity testing in patients with and without cataract using the controlled point source light-emitting diode (LED) glare tester (EpiGlare Tester; Epico, LLC, Columbus, OH), a new medical device for identification of glare disability. This prospective, multicenter study enrolled 40 patients (80 eyes with cataracts) and 49 control subjects (98 eyes without cataracts). Corrected distance visual acuity (CDVA) was measured with and without glare using the EpiGlare Tester as a glare source. Functional visual ability was evaluated using driving and glare subscales from the Refractive Status Vision Profile questionnaire. The primary efficacy measure was change in CDVA measurement with and without glare in patients with senile cataract compared to participants without cataract. Secondary efficacy measures included correlation of the CDVA change caused by functional glare disability and subjective patient and investigator assessments. CDVA reduction was greater for patients with cataract, with a mean reduction of -0.49 ± 0.3 logMAR, than for participants without cataracts at -0.13 ± 0.2 logMAR (P tester demonstrated the adverse effect on visual acuity due to glare in patients with cataract, accurately simulated night driving glare issues for patients with cataracts, and was rated as easy to use and useful by investigators. Copyright 2015, SLACK Incorporated.

  4. The validity and intra-tester reliability of markerless motion capture to analyse kinematics of the BMX Supercross gate start.

    Science.gov (United States)

    Grigg, Josephine; Haakonssen, Eric; Rathbone, Evelyne; Orr, Robin; Keogh, Justin W L

    2017-11-13

    The aim of this study was to quantify the validity and intra-tester reliability of a novel method of kinematic measurement. The measurement target was the joint angles of an athlete performing a BMX Supercross (SX) gate start action through the first 1.2 s of movement in situ on a BMX SX ramp using a standard gate start procedure. The method employed GoPro® Hero 4 Silver (GoPro Inc., USA) cameras capturing data at 120 fps 720 p on a 'normal' lens setting. Kinovea 0.8.15 (Kinovea.org, France) was used for analysis. Tracking data was exported and angles computed in Matlab (Mathworks®, USA). The gold standard 3D method for joint angle measurement could not safely be employed in this environment, so a rigid angle was used. Validity was measured to be within 2°. Intra-tester reliability was measured by the same tester performing the analysis twice with an average of 55 days between analyses. Intra-tester reliability was high, with an absolute error <6° and <9 frames (0.075 s) across all angles and time points for key positions, respectively. The methodology is valid within 2° and reliable within 6° for the calculation of joint angles in the first ~1.25 s.

  5. Self-Assessment and Tutor Assessment in Online Language Learning Materials: InGenio FCE Online Course and Tester

    Science.gov (United States)

    Sevilla-Pavón, Ana; Martínez-Sáez, Antonio; Macario Siqueira, José

    2011-01-01

    This chapter addresses different modalities of assessment, provides an overview of the assessment processes of the basic skills (reading, writing, listening and speaking) tested by the Cambridge First Certificate in English (FCE) examination, and explores the ways in which the FCE Online Course and Tester--the resources provided through the…

  6. SUPER HARD SURFACED POLYMERS

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-01

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

  7. Hard Probes at RHIC

    Directory of Open Access Journals (Sweden)

    Bielčíková Jana

    2014-04-01

    Full Text Available Measurements of jets and heavy flavour, the so called hard probes, play a crucial role in understanding properties of hot and dense nuclear matter created in high energy heavy-ion collisions. The measurements at the Relativistic Heavy Ion Collider (RHIC showed that in central Au+Au collisons at RHIC energy ( √sNN = 200 GeV the nuclear matter created has properties close to those of perfect liquid, manifests partonic degrees of freedom and is opaque to hard probes. In order to draw quantitative conclusions on properties of this hot and dense nuclear matter reference measurements in proton-proton collisions and d+Au collisions are essential to estimate cold nuclear matter effects. In this proceedings a review of recent results on hard probes measurements in p+p, d+Au and A+A collisions as well as of beam energy dependence of jet quenching from STAR and PHENIX experiments at RHIC is presented.

  8. Novel in situ mechanical testers to enable integrated metal surface micro-machines.

    Energy Technology Data Exchange (ETDEWEB)

    Follstaedt, David Martin; de Boer, Maarten Pieter; Kotula, Paul Gabriel; Hearne, Sean Joseph; Foiles, Stephen Martin; Buchheit, Thomas Edward; Dyck, Christopher William

    2005-10-01

    The ability to integrate metal and semiconductor micro-systems to perform highly complex functions, such as RF-MEMS, will depend on developing freestanding metal structures that offer improved conductivity, reflectivity, and mechanical properties. Three issues have prevented the proliferation of these systems: (1) warpage of active components due to through-thickness stress gradients, (2) limited component lifetimes due to fatigue, and (3) low yield strength. To address these issues, we focus on developing and implementing techniques to enable the direct study of the stress and microstructural evolution during electrodeposition and mechanical loading. The study of stress during electrodeposition of metal thin films is being accomplished by integrating a multi-beam optical stress sensor into an electrodeposition chamber. By coupling the in-situ stress information with ex-situ microstructural analysis, a scientific understanding of the sources of stress during electrodeposition will be obtained. These results are providing a foundation upon which to develop a stress-gradient-free thin film directly applicable to the production of freestanding metal structures. The issues of fatigue and yield strength are being addressed by developing novel surface micromachined tensile and bend testers, by interferometry, and by TEM analysis. The MEMS tensile tester has a ''Bosch'' etched hole to allow for direct viewing of the microstructure in a TEM before, during, and after loading. This approach allows for the quantitative measurements of stress-strain relations while imaging dislocation motion, and determination of fracture nucleation in samples with well-known fatigue/strain histories. This technique facilitates the determination of the limits for classical deformation mechanisms and helps to formulate a new understanding of the mechanical response as the grain sizes are refined to a nanometer scale. Together, these studies will result in a science

  9. Inter-tester reliability of selected clinical tests for long-lasting temporomandibular disorders.

    Science.gov (United States)

    Julsvoll, Elisabeth Heggem; Vøllestad, Nina Køpke; Opseth, Gro; Robinson, Hilde Stendal

    2017-09-01

    Clinical tests used to examine patients with temporomandibular disorders vary in methodological quality, and some are not tested for reliability. The purpose of this cross-sectional study was to evaluate inter-tester reliability of clinical tests and a cluster of tests used to examine patients with long-lasting temporomandibular disorders. Forty patients with pain in the temporomandibular area treated by health-professionals were included. They were between 18-70 years, had 65 symptomatic (33 right/32 left) and 15 asymptomatic joints. Two manual therapists examined all participants with selected tests. Percentage agreement and the kappa coefficient ( k ) with 95% confidence interval (CI) were used to evaluate the tests with categorical outcomes. For tests with continuous outcomes, the relative inter-tester reliability was assessed by the intraclass-correlation-coefficient (ICC 3,1 , 95% CI) and the absolute reliability was calculated by the smallest detectable change (SDC). The best reliability among single tests was found for the dental stick test, the joint-sound test ( k  = 0.80-1.0) and range of mouth-opening (ICC 3,1 (95% CI) = 0.97 (0.95-0.98) and SDC = 4 mm). The reliability of cluster of tests was excellent with both four and five positive tests out of seven. The reliability was good to excellent for the clinical tests and the cluster of tests when performed by experienced therapists. The tests are feasible for use in the clinical setting. They require no advanced equipment and are easy to perform.

  10. Investigation of dentin hardness in roots exhibiting the butterfly effect.

    Science.gov (United States)

    Russell, Assil A; Chris He, Li Hong; Chandler, Nicholas P

    2014-06-01

    Most vertical root fractures occur in root canal treated teeth, and they usually run in a buccolingual direction. The butterfly effect is an optical phenomenon seen in some sections of tooth roots. The aim was to investigate the microhardness of dentin in mesiodistal and buccolingual cross sections of roots exhibiting the effect. Thirty extracted single-rooted teeth were allocated according to patient age: group 1, 15-24 years; group 2, 25-44 years; and group 3, 45 years and older. Roots were embedded in acrylic and cut into ten 1-mm-thick cross sections. Sections were viewed under a light microscope and coded (1 or 2) according to presence or absence of the butterfly effect. A root scored 20 when all levels featured the butterfly appearance. The 2 teeth with the highest score from each group and 2 control teeth with the minimum score (10) were selected. Two adjacent, consecutive cross sections were chosen from the middle of the roots. Vickers microhardness testing was carried out on the dentin walls. Mean hardness scores were highest mesiodistally (83.7 kgf/mm(2)) and lowest buccolingually (56.4 kgf/mm(2)), a significant difference (P = .028). This trend was found across all age groups. Root sections with the butterfly effect are harder mesiodistally. This might explain the high prevalence of vertical root fractures that run buccolingually. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  11. Hardness evolution of AZ80 magnesium alloy processed by HPT at different temperatures

    Directory of Open Access Journals (Sweden)

    Saad A. Alsubaie

    2017-10-01

    Full Text Available Discs of an extruded AZ80 magnesium alloy were processed by high-pressure torsion (HPT using 6.0 GPa up to 10 turns at different temperatures (296 K and 473 K. The disc surfaces and cross-sectional planes were examined before and after processing using scanning electron microscopy (SEM and Vickers microhardness (Hv. The microhardness results at the surface show differences in the strength of the material as a function of distance from the disc centres up to saturation, as well as a function of distance from the bottom to the surface in the cross-sectional plane. This study analyses the effect of processing temperature on the evolution of microhardness in the AZ80 magnesium alloy processed by high-pressure torsion. Keywords: Hardness, High-pressure torsion, Magnesium alloy, Severe plastic deformation

  12. Intermittent chaos and sliding window symbol sequence statistics-based early fault diagnosis for hydraulic pump on hydraulic tube tester

    Science.gov (United States)

    Zhao, Zhen; Jia, Mingxing; Wang, Fuli; Wang, Shu

    2009-07-01

    To ensure the safety, continuity of production, make a reasonable maintenance plan, save the cost of maintenance for hydraulic tube tester, it is needed to quickly identify an assignable cause of a fault. This paper is concerned with early fault diagnosis of hydraulic pump which are the heart of hydraulic tube tester. Considering that the signal of the hydraulic pump early fault is a periodic weak signal, an intermittent chaos, sliding window symbol sequence statistics-based method is proposed to detect the early fault of one single piston loose shoes of hydraulic pump on a hydraulic tube tester. The approach presented is based on the insight that the phase transition of chaos oscillator, for example, the Duffing oscillator, is very sensitive to a periodic weak signal having little angular frequency difference with the referential signal of the oscillator. While observing the intermittent chaos phenomenon through figure is not easy for computer, a sliding window symbol sequence statistics is developed to realize real-time computer observation of this phenomenon. Rather more, this paper takes a trick to decreasing the computational complexity of the sliding window symbol sequence statistics method, also analyzes the influences of different window size, depths of the symbol tree on the information entropy. At last, a control limit is introduced to realize automatic early fault alarm. The resultant approach is experimented with data simulated from an AMESim model of hydraulic tube tester. The results indicate that the proposed approach is capable of detecting the signal of hydraulic pump early fault on hydraulic tube tester.

  13. Effect of antibacterial agents on the surface hardness of a conventional glass-ionomer cement

    Science.gov (United States)

    TÜZÜNER, Tamer; ULUSU, Tezer

    2012-01-01

    In atraumatic restorative treatment (ART), caries removal with hand excavation instruments is not as efficient as that with rotary burs in eliminating bacteria under the glass ionomer cements (GICs). Thus, different antibacterial agents have been used in recent studies to enhance the antibacterial properties of the GICs, without jeopardizing their basic physical properties. Objective The objective of this study was to evaluate the effect of antibacterial agents on the surface hardness of a conventional GIC (Fuji IX) using Vickers microhardness [Vickers hardness number (VHN)] test. Material and Methods Cetrimide (CT), cetylpyridinium chloride (CPC) and chlorhexidine (CHX) were added to the powder and benzalkonium chloride (BC) was added to the liquid of Fuji IX in concentrations of 1% and 2%, and served as the experimental groups. A control group containing no additive was also prepared. After the completion of setting reaction, VHN measurements were recorded at 1, 7, 15, 30, 60, and 90 days after storage in 37ºC distilled water. A one-way ANOVA was performed followed by a Dunnett t test and Tamhane T2 tests and also repeated measurements ANOVA was used for multiple comparisons in 95% confidence interval. Results VHN results showed significant differences between the control and the experimental groups at all time periods (phardness of set cements. Conclusions Despite the decreased microhardness values in all experimental groups compared to the controls after 7 up to 90 days, incorporating certain antibacterial agents into Fuji IX GIC showed tolerable microhardness alterations within the limitations of this in vitro study. PMID:22437677

  14. Effect of beverages and mouthwashes on the hardness of polymers used in intraoral prostheses.

    Science.gov (United States)

    Goiato, Marcelo Coelho; Dos Santos, Daniela Micheline; Andreotti, Agda Marobo; Nobrega, Adhara Smith; Moreno, Amalia; Haddad, Marcela Filié; Pesqueira, Aldiéris Alves

    2014-10-01

    The mechanical properties of acrylic resins used in intraoral prostheses may be altered by frequent exposure to liquids such as beverages and mouthwashes. This study aimed to evaluate the effect of thermocycling and liquid immersion on the hardness of four brands of acrylic resins commonly used in removable prostheses (Onda Cryl, QC-20, Clássico, Lucitone). For each brand of resin, seven specimens were immersed in each of six solutions (coffee, cola, red wine, Plax-Colgate, Listerine [LI], Oral B), and seven more were placed in artificial saliva (control). The hardness was tested using a microhardness tester before and after 5000 thermocycles and after 1, 3, 24, 48, and 96 hours of immersion. The results were analyzed using three-way repeated-measures ANOVA and Tukey's test (p hardness of the resins decreased following thermocycling and immersion in the solutions. Specimens immersed in cola and wine exhibited significant decreases in hardness after immersion for 96 hours, although the greatest significant decrease in hardness occurred in specimens immersed in LI. However, according to American Dental Association specification 12, the Knoop hardness of acrylic resins for intraoral prostheses should not be below 15. Thus, the median values of superficial hardness observed in most of the acrylic resins in this study are considered clinically acceptable. The microhardness of polymers used for intraoral prostheses decreases following thermocycling. Among specimens immersed in beverages, those immersed in cola or wine experienced the greatest decrease in microhardness. Immersion of acrylic resins in LI significantly decreased the microhardness in relation to the initial value. Among the resins assessed, QC-20 exhibited the lowest initial hardness. © 2014 by the American College of Prosthodontists.

  15. Evaluation of methods to predict safe welding conditions and maximum HAZ hardness in steel welding

    Energy Technology Data Exchange (ETDEWEB)

    Tronskar, J.P. [Det Norske Veritas Industri Norge AS, Oslo (Norway)

    1993-12-31

    During the last ten years new structural steels of improved weldability have been introduced. In particular structural steels for the fabrication of offshore structures have been greatly improved in this respect throughout this period. These steels have lean chemical compositions which are generally outside the range for which the existing HAZ hardness criteria and the International Institute of Welding carbon equivalent (CEIIW) formula were originally developed. However, there are indications that the BS 5135:1984 method is not satisfactory for low carbon low CEIIW carbon equivalent steels. This paper presents the results from investigations of the weldability of three normalized (R{sub e min} 350 MPa) and three quenched and tempered (R{sub e min} 500 MPa) offshore structural steels. Weldability testing was conducted to study the relative performance of the different steels and to obtain a comparison between the capability of the different methods to predict safe welding conditions to avoid cold cracking in steel welding. Maximum HAZ hardness restrictions are often a point of contention between fabricators and their clients due to the difficulties often experienced in meeting these hardness requirements. Problems meeting maximum HAZ hardness requirements have been encountered for applications where NACE maximum hardness HRC 22 or Vickers HV10 260 have been imposed for materials exposed to sour service in oil and gas production, processing and transportation. Many attempts have been made to develop empirical formulae for the estimation of maximum HAZ hardnesses. This paper presents some of the more successful approaches proposed to date and compares their performance.

  16. Hardness of heat-polymerized acrylic resins after disinfection and long-term water immersion.

    Science.gov (United States)

    Neppelenbroek, Karin Hermana; Pavarina, Ana Cláudia; Vergani, Carlos Eduardo; Giampaolo, Eunice Teresinha

    2005-02-01

    In selecting a disinfectant for dental prostheses, compatibility between the disinfectant and the type of denture base material must be considered to avoid adverse effects on the hardness of the acrylic resin. This study investigated the hardness of 2 denture base resins after disinfection and long-term water immersion. Thirty-two disk-shaped specimens (13 mm in diameter and 8 mm thick) were fabricated from each resin (Lucitone 550 and QC-20), polished, stored in water at 37 degrees C for 48 hours, and submitted to hardness tests (Vickers hardness number [VHN]) before disinfection. Disinfection methods included scrubbing with 4% chlorhexidine gluconate for 1 minute, immersion for 10 minutes in 1 of the tested disinfectant solutions (n=8) (3.78% sodium perborate, 4% chlorhexidine gluconate, or 1% sodium hypochorite), and immersion in water for 3 minutes. The disinfection procedures were repeated 4 times, and 12 hardness measurements were made on each specimen. Control specimens (not disinfected) were stored in water for 56 minutes. Hardness tests (VHN) were also performed after 15, 30, 60, 90, and 120 days of storage in water. Statistical analyses of data were conducted with a repeated measures 3-way analysis of variance (ANOVA) and Tukey post-hoc test (alpha=.05). Mean values +/- SD for Lucitone 550 (16.52 +/- 0.94 VHN) and QC-20 (9.61 +/- 0.62 VHN) demonstrated a significant (P disinfection, regardless of material and disinfectant solutions used (Lucitone 550: 15.25 +/- 0.74; QC-20: 8.09 +/- 0.39). However, this effect was reversed after 15 days of storage in water. Both materials exhibited a continuous increase (P disinfection regardless of the disinfectant solution used.

  17. HIV prevalence and high-risk sexual behaviours among MSM repeat and first-time testers in China: implications for HIV prevention

    Directory of Open Access Journals (Sweden)

    Xue Bai

    2014-07-01

    Full Text Available Introduction: Little is known about HIV testing, HIV infection and sexual behaviour among bathhouse patrons in China. This study aims to assess differences in HIV prevalence and high-risk sexual behaviours between repeat and first-time testers among men who have sex with men (MSM attending bathhouse in Tianjin, China. Methods: Between March 2011 and September 2012, a HIV voluntary counselling and testing station was established in a gay bathhouse, which provided HIV testing and conducted a survey among participants recruited through snowball sampling. Differences in demographic and high-risk sexual behaviours between repeat and first-time testers were assessed using the chi-square test. Univariate and multivariate logistic regression analyses were conducted to identify predictors for HIV infection. Results: Of the 1642 respondents, 699 (42.6% were repeat testers and 943 (57.4% were first-time testers. Among repeat testers, a higher proportion were men aged 18 to 25, single, better educated, had a history of STIs and worked as male sex workers or “money boys” (MBs. Repeat testers were less likely to report having unprotected anal intercourse in the past six months. The overall HIV prevalence was 12.4% (203/1642. There was no difference in HIV prevalence between repeat (11.2%, 78/699 and first-time (13.3%, 125/943 testers. The HIV prevalence increased with age among first-time testers (χ 2 trend=9.816, p=0.002. First-time MB testers had the highest HIV prevalence of 34.5%. Conclusions: MSM attending bathhouse had an alarmingly high HIV infection rate, particularly in MB. Targeted interventions are urgently needed especially focusing on older MSM and MBs.

  18. Revisiting the definition of local hardness and hardness kernel.

    Science.gov (United States)

    Polanco-Ramírez, Carlos A; Franco-Pérez, Marco; Carmona-Espíndola, Javier; Gázquez, José L; Ayers, Paul W

    2017-05-17

    An analysis of the hardness kernel and local hardness is performed to propose new definitions for these quantities that follow a similar pattern to the one that characterizes the quantities associated with softness, that is, we have derived new definitions for which the integral of the hardness kernel over the whole space of one of the variables leads to local hardness, and the integral of local hardness over the whole space leads to global hardness. A basic aspect of the present approach is that global hardness keeps its identity as the second derivative of energy with respect to the number of electrons. Local hardness thus obtained depends on the first and second derivatives of energy and electron density with respect to the number of electrons. When these derivatives are approximated by a smooth quadratic interpolation of energy, the expression for local hardness reduces to the one intuitively proposed by Meneses, Tiznado, Contreras and Fuentealba. However, when one combines the first directional derivatives with smooth second derivatives one finds additional terms that allow one to differentiate local hardness for electrophilic attack from the one for nucleophilic attack. Numerical results related to electrophilic attacks on substituted pyridines, substituted benzenes and substituted ethenes are presented to show the overall performance of the new definition.

  19. Hardness and Wear Resistance of TiC-Fe-Cr Locally Reinforcement Produced in Cast Steel

    Directory of Open Access Journals (Sweden)

    Olejnik E.

    2016-06-01

    Full Text Available In order to increase wear resistance cast steel casting the TiC-Fe-Cr type composite zones were fabricated. These zones were obtained by means of in situ synthesis of substrates of the reaction TiC with a moderator of a chemical composition of white cast iron with nickel of the Ni-Hard type 4. The synthesis was carried out directly in the mould cavity. The moderator was applied to control the reactive infiltration occurring during the TiC synthesis. The microstructure of composite zones was investigated by electron scanning microscopy, using the backscattered electron mode. The structure of composite zones was verified by the X-ray diffraction method. The hardness of composite zones, cast steel base alloy and the reference samples such as white chromium cast iron with 14 % Cr and 20 % Cr, manganese cast steel 18 % Mn was measured by Vickers test. The wear resistance of the composite zone and the reference samples examined by ball-on-disc wear test. Dimensionally stable composite zones were obtained containing submicron sizes TiC particles uniformly distributed in the matrix. The macro and microstructure of the composite zone ensured three times hardness increase in comparison to the cast steel base alloy and one and a half times increase in comparison to the white chromium cast iron 20 % Cr. Finally ball-on-disc wear rate of the composite zone was five times lower than chromium white cast iron containing 20 % Cr.

  20. Synergetic effect of additives on the hardness and adhesion of thin electrodeposited copper films

    Directory of Open Access Journals (Sweden)

    Mladenović Ivana

    2017-01-01

    Full Text Available Thin copper films were electrodeposited on a polycrystalline coldrolled copper substrate. The composition of the laboratory-made copper sulphate electrolyte was changed by the addition of various additives. The influence of chloride ion (Cl-, polyethylene glycol (PEG and 3-mercapto-1-propane sulfonic acid (MPSA on mechanical and adhesion properties of the electrodeposited copper films was investigated using Vickers microindentation technique. Calculations of the film hardness and adhesion were carried out using composite hardness models of Korsunsky and Chen-Gao. The hardness of the composite system is influenced by the adhesion of the copper film to the substrate. Increasing adhesion corresponds to increasing values of the calculated adhesion parameter b, named the critical reduced depth. When additives are added to a plating solution, the copper deposition mechanism is changed and fine-grained microstructure without the formation of microscopic nodules is obtained. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR 32008, Grant no. TR 34011 and Grant no. III 45019

  1. Hard photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Klasen, M. [Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier / CNRS-IN2P3, 53 Avenue des Martyrs, F-38026 Grenoble (France)

    2007-07-01

    In view of possible photoproduction studies in ultra-peripheral heavy-ion collisions at the LHC, we briefly review the present theoretical understanding of photons and hard photoproduction processes at HERA, discussing the production of jets, light and heavy hadrons, quarkonia, and prompt photons. We address in particular the extraction of the strong coupling constant from photon structure function and inclusive jet measurements, the infrared safety and computing time of jet definitions, the sensitivity of di-jet cross sections on the parton densities in the photon, factorization breaking in diffractive di-jet production, the treatment of the heavy-quark mass in charm production, the relevance of the color-octet mechanism for quarkonium production, and isolation criteria for prompt photons. (author)

  2. Pengaruh Ball Peening terhadap Kekerasan Baja Tahan Karat AISI 316L

    Directory of Open Access Journals (Sweden)

    Teguh Dwi Widodo

    2017-03-01

    Full Text Available In this work, ball peening was performed in order to evaluate its effect on the AISI 316L hardness. The process was conducted by employing AISI E52100 Chrome Steel ball which has hardness 752 HVN as bomber. In this research ball peening process was performed at three different nozzle pressure (6, 7, and 8 bar for 5 minutes. Vickers Micro Hardness Tester and Digital Optical Microscope was used to characterize the samples hardness and grains structure respectively. The results showed that the hardness of AISI 316L was improved. It may due to plastic deformation which toke places on its grains.

  3. Intra-tester reproducibility of pressure biofeedback in measurement of transversus abdominis function.

    Science.gov (United States)

    Storheim, Kjersti; Bø, Kari; Pederstad, Olav; Jahnsen, Reidun

    2002-01-01

    Strength, co-ordination and timing of transversus abdominis muscle contraction may be important in stabilizing the low back, and contraction of this particular abdominal muscle may be one factor capable of preventing and reducing low back pain in sport and in activities of daily living. The function and strength of the transversus abdominis muscle is difficult to measure. The pressure biofeedback unit (PBU) is a device designed to teach and measure transversus abdominis muscle function. The purpose of the present study was to evaluate intra-tester reproducibility of the PBU. The study used a test-retest design. Fifteen healthy subjects (mean age 22.2 years, range 19-28 years) with no history of low back pain participated in the study. After two sessions of practising transversus abdominis muscle contraction, its function was measured in prone position with the PBU device placed over the transversus abdominis muscle. Subjects were instructed to draw in the abdominal wall (for example, lifting it away from the device) after a standardized procedure. Two tests were conducted on two different days, with a seven-day interval in between. Coefficient of variance (CV) was 21.0% and the standard deviation (SD) of delta was 1.59. The use of the PBU should be improved for scientific purposes. However, the device may have a role in providing biofeedback to assist in the instruction of correct transversus abdominis muscle contraction.

  4. Ignition delay times of Gasoline Distillation Cuts measured with Ignition Quality Tester

    KAUST Repository

    Naser, Nimal

    2017-04-21

    Tailoring fuel properties to maximize the efficiency of internal combustion engines is a way towards achieving cleaner combustion systems. In this work, the ignition properties of various gasoline fuel distillation cuts are analyzed to better understand fuel properties of the full boiling range fuel. An advanced distillation column (ADC) provides a more realistic representation of volatility characteristics, which can be modeled using equilibrium thermodynamic methods. The temperature reported is that of the liquid, as opposed to the vapor temperature in conventional ASTM D86 distillation standard. Various FACE (fuels for advanced combustion engines) gasolines were distilled and various cuts were obtained. The separated fractions were then tested in an ignition quality tester (IQT) to see the effect of chemical composition of different fractions on their ignition delay time. Fuels with lower aromatic content showed decreasing ignition delay time with increasing boiling point (i.e., molecular weight). However, fuels with higher aromatic content showed an initial decrease in ignition delay time with increasing boiling point, followed by drastic increase in ignition delay time due to fractions containing aromatics. This study also provides an understanding on contribution of different fractions to the ignition delay time of the fuel, which provides insights into fuel stratification utilized in gasoline compression ignition (GCI) engines to tailor heat release rates.

  5. Quantifying effects of particulate properties on powder flow properties using a ring shear tester.

    Science.gov (United States)

    Hou, Hao; Sun, Changquan Calvin

    2008-09-01

    Effects of particle size, morphology, particle density, and surface silicification, on powder flow properties were investigated using a ring shear tester. Flow properties were quantified by flow function (FF), that is, unconfined yield strength, f(c), as a function of major principal stress. A total of 11 powders from three series of microcrystalline cellulose (MCC): Avicel (regular MCC, elongated particles), Prosolv (silicified MCC, elongated particles), and Celphere (spherical MCC), were studied. Particle size distribution in each type of MCC was systematically different. Within each series, smaller particles always led to poorer powder flow properties. The slope of FF line was correlated to degree of powder consolidation by external stress. A key mechanism of the detrimental effect of particle size reduction on flow properties was the larger powder specific surface area. Flow properties of Celphere were significantly better than Avicel of comparable particles size, suggesting spherical morphology promoted better powder flow properties. Flow properties of powders different in densities but similar in particle size, shape, and surface properties were similar. When corrected for density effect, higher particle density corresponded to better flow behavior. Surface silicification significantly improved flow properties of finer MCC, but did not improve those of coarser.

  6. Calibrators measurement system for headlamp tester of motor vehicle base on machine vision

    Science.gov (United States)

    Pan, Yue; Zhang, Fan; Xu, Xi-ping; Zheng, Zhe

    2014-09-01

    With the development of photoelectric detection technology, machine vision has a wider use in the field of industry. The paper mainly introduces auto lamps tester calibrator measuring system, of which CCD image sampling system is the core. Also, it shows the measuring principle of optical axial angle and light intensity, and proves the linear relationship between calibrator's facula illumination and image plane illumination. The paper provides an important specification of CCD imaging system. Image processing by MATLAB can get flare's geometric midpoint and average gray level. By fitting the statistics via the method of the least square, we can get regression equation of illumination and gray level. It analyzes the error of experimental result of measurement system, and gives the standard uncertainty of synthesis and the resource of optical axial angle. Optical axial angle's average measuring accuracy is controlled within 40''. The whole testing process uses digital means instead of artificial factors, which has higher accuracy, more repeatability and better mentality than any other measuring systems.

  7. Bit error rate tester using fast parallel generation of linear recurring sequences

    Science.gov (United States)

    Pierson, Lyndon G.; Witzke, Edward L.; Maestas, Joseph H.

    2003-05-06

    A fast method for generating linear recurring sequences by parallel linear recurring sequence generators (LRSGs) with a feedback circuit optimized to balance minimum propagation delay against maximal sequence period. Parallel generation of linear recurring sequences requires decimating the sequence (creating small contiguous sections of the sequence in each LRSG). A companion matrix form is selected depending on whether the LFSR is right-shifting or left-shifting. The companion matrix is completed by selecting a primitive irreducible polynomial with 1's most closely grouped in a corner of the companion matrix. A decimation matrix is created by raising the companion matrix to the (n*k).sup.th power, where k is the number of parallel LRSGs and n is the number of bits to be generated at a time by each LRSG. Companion matrices with 1's closely grouped in a corner will yield sparse decimation matrices. A feedback circuit comprised of XOR logic gates implements the decimation matrix in hardware. Sparse decimation matrices can be implemented with minimum number of XOR gates, and therefore a minimum propagation delay through the feedback circuit. The LRSG of the invention is particularly well suited to use as a bit error rate tester on high speed communication lines because it permits the receiver to synchronize to the transmitted pattern within 2n bits.

  8. Development of output signal-to-noise ratio tester for microchannel plate and fluorescent screen component

    Science.gov (United States)

    Wu, Xinglin; Qiu, Yafeng; Zhou, Jin; Qian, Yunsheng

    The core components of Image intensifier is microchannel plate (MCP) and fluorescent screen component. The present paper deeply studies output signal-to-noise ratio (SNR) characteristics of MCP and fluorescent screen component. A tester system using to the evaluation of characteristics of the output SNR of MCP and fluorescent screen component, consists of a vacuum system, a surface electron source, mechanical mechanism components ,a high-voltage power supply system, a signal processing system, communication interfaces, a data acquisition and control system, computer system, and testing software. a hot cathode used as an electron source, generates a surface electron flow to provide the input signal. A photomultiplier tube is used to detection faceplate output brightness of the light spot. Then, the output SNR of MCP and fluorescent screen component is processed with a combination of methods of the hardware filter and digital filtering software. The output SNR of MCP and fluorescent screen component is measured under different conditions, and the results are analyzed. This test system Provide a technical to promote the image intensifier research, and experience to testing other parameters or in other areas of research.

  9. ON/OFF POWER SWITCH DAN REMOTE CONTROL BERBASIS MICROCONTROLLER ATMEGA8 SEBAGAI RELIABILITY TESTER CRT DANLCD TV

    Directory of Open Access Journals (Sweden)

    Fina Supegina

    2013-10-01

    Full Text Available Mikrokontroler sebagai suatu terobosan teknologi mikroprosesor dan mikrokomputer, hadir memenuhi kebutuhan pasar dan teknologi baru. Sebagai teknologi baru, yaitu teknologi semikonduktor dengan kandungan transistor yang lebih banyak namun hanya membutuhkan ruang yang lebih kecil serta dapat diproduksi secara masal sehingga harganya menjadi lebih murah (dibandingkan dengan mikroprosesor. Sebagai kebutuhan pasar, mikrokontroler hadir untuk memenuhi selera industri dan para konsumen akan kebutuhan dan keinginan alat-alat bantu yang lebih baik dan canggih. Quality Engineering merupakan bagian dari Departemen Quality Assurance yang melakukan proses studi dan menganalisa semua produk baru sebelum diproduksi secara masal (Mass production dan sebelum dijual ke pasaran lokal maupun ekspor, pada bagian ini dilakukan proses pembelajaran dan penganalisaan secara detail kemampuan komponen pada CRT TV dan LCD TV yang dapat mempengaruhi kinerja dari produk itu sendiri. Disamping itu juga dilakukanlah pengetesan terhadap reliability (ketahanan suatu produk baru ini salah satu dengan cara menghidupkan dan mematikan power switch dan juga melalui remote kontrolnya. Pada saat melakukan pengetesan reliability ini terasa sangat membosankan, melelahkan karena dilakukan secara manual, jadi dengan kondisi seperti ini cukup menyita waktu dan menghambat bagi seorang engineer dalam mempelajari dan menganalisa dari produk baru lebih lanjut. Solusi dari masalah yang ada dihadapi oleh engineer untuk menunjang dan mengetahui kemampuan komponen yang dipakai CRT TV dan LCD TV adalah dengan dibuatnya sebuah alat Reliability Tester Otomatic yang memanfaatkan sebuah IC Mikrokontroler ATmega8 sebagai otak pengendalinya. Dengan adanya sebuah Reliability Tester Otomatic tersebut, dapat mengetahui ketahanan dari produk televisi baik CRT TV juga LCD TV saat dihidupkan dan dimatikan secara berulang-ulang, sebelum dipergunakan oleh konsumen. Efektivitas kerja seorang engineer yang

  10. Blinded Comparison between an In-Air Reverberation Method and an Electronic Probe Tester in the Detection of Ultrasound Probe Faults.

    Science.gov (United States)

    Dudley, Nicholas J; Woolley, Darren J

    2017-12-01

    The aim of this study was to perform a blinded trial, comparing the results of a visual inspection of the in-air reverberation pattern with the results of an electronic probe tester in detecting ultrasound probe faults. Sixty-two probes were tested. A total of 28 faults were found, 3 only by in-air reverberation assessment and 2 only by the electronic probe tester. The electronic probe tester provided additional information regarding the location of the fault in 74% of the cases in which both methods detected a fault. It is possible to detect the majority of probe faults by visual inspection and in-air reverberation assessment. The latter provides an excellent first-line test, easily performed on a daily basis by equipment users. An electronic probe tester is required if detailed evaluation of faults is necessary. Copyright © 2017 World Federation for Ultrasound in Medicine and Biology. All rights reserved.

  11. Janka hardness using nonstandard specimens

    Science.gov (United States)

    David W. Green; Marshall Begel; William Nelson

    2006-01-01

    Janka hardness determined on 1.5- by 3.5-in. specimens (2×4s) was found to be equivalent to that determined using the 2- by 2-in. specimen specified in ASTM D 143. Data are presented on the relationship between Janka hardness and the strength of clear wood. Analysis of historical data determined using standard specimens indicated no difference between side hardness...

  12. Combining ability of S3 progenies for key agronomic traits in popcorn: comparison of testers in top-crosses.

    Science.gov (United States)

    de Lima, V J; do Amaral Junior, A T; Kamphorst, S H; Pena, G F; Leite, J T; Schmitt, K F M; Vittorazzi, C; de Almeida Filho, J E; Mora, F

    2016-12-02

    The successful development of hybrid cultivars depends on the reliability of estimated combining ability of the parent lines. The objectives of this study were to assess the combining ability of partially inbred S3 families of popcorn derived from the open-pollinated variety UENF 14, via top-crosses with four testers, and to compare the testers for their ability to discriminate the S3 progenies. The experiment was conducted in the 2015/2016 crop season, in an incomplete-block (Lattice) design with three replications. The following agronomic traits were evaluated: average plant height, grain yield (GY), popping expansion (PE), and expanded popcorn volume per hectare. The top-cross hybrid, originating from the BRS-Angela vs S3 progeny 10 combination, was indicated as promising, showing high values for specific combining ability for GY and PE. For the S3 progenies that showed high and positive GCA values for GY and PE, the continuity of the breeding program is recommended, with the advance of self-pollination generations. Fasoulas' differentiation index discriminated the BRS-Angela tester as the most suitable for identifying the superior progenies.

  13. Scheduling Semiconductor Multihead Testers Using Metaheuristic Techniques Embedded with Lot-Specific and Configuration-Specific Information

    Directory of Open Access Journals (Sweden)

    Yi-Feng Hung

    2013-01-01

    Full Text Available In the semiconductor back-end manufacturing, the device test central processing unit (CPU is most costly and is typically the bottleneck machine at the test plant. A multihead tester contains a CPU and several test heads, each of which can be connected to a handler that processes one lot of the same device. The residence time of a lot is closely related to the product mix on test heads, which increases the complexity of this problem. It is critical for the test scheduling problem to reduce CPU's idle time and to increase tester utilization. In this paper, a multihead tester scheduling problem is formulated as an identical parallel machine scheduling problem with the objective of minimizing makespan. A heuristic grouping method is developed to obtain a good initial solution in a short time. Three metaheuristic techniques, using lot-specific and configuration-specific information, are proposed to receive a near-optimum and are compared to traditional approaches. Computational experiments show that a tabu search with lot-specific information outperforms all other competing approaches.

  14. 2TB hard disk drive

    CERN Multimedia

    This particular object was used up until 2012 in the Data Centre. It slots into one of the Disk Server trays. Hard disks were invented in the 1950s. They started as large disks up to 20 inches in diameter holding just a few megabytes (link is external). They were originally called "fixed disks" or "Winchesters" (a code name used for a popular IBM product). They later became known as "hard disks" to distinguish them from "floppy disks (link is external)." Hard disks have a hard platter that holds the magnetic medium, as opposed to the flexible plastic film found in tapes and floppies.

  15. The influence of topical application of grapeseed extract gel on enamel surface hardness after demineralization

    Science.gov (United States)

    Saragih, D. A.; Herda, E.; Triaminingsih, S.

    2017-08-01

    The aim of this study was to analyze the influence of topical application of 6.5% and 12.5% grapeseed extract gels for duration of application 16 and 32 minutes on the enamel surface hardness following tooth demineralization by an energy drink. The samples were 21 bovine teeth that underwent demineralization by immersion in the energy drink for 5 minutes in an incubator at 37°C. The demineralized specimens were randomly divided into a control group and 2 treatment groups. The control group was immersed in artificial saliva for 6 hours at 37°C, whereas the treatment groups were treated with topical 6.5% and 12.5% grapeseed extract gels for durations of 16 and 32 minutes and then immersed in artificial saliva for 6 hours at 37°C. The hardness was measured with a Knoop hardness tester. Statistical analysis by repeated ANOVA and one-way ANOVA revealed a significant increase in the enamel hardness value (p0.05).

  16. Inter- and intra-tester reliability of clinical measurement to determine medio-lateral patellar position using a pachymeter or visual assessment.

    Science.gov (United States)

    Sacco, I C N; Onodera, A N; Butugan, M K; Taddei, U T; Mendes, Y C; Galhardo, B; Padua, M; Dreyer, S H; Lobo, R A S; Aliberti, S

    2010-01-01

    The aim was to investigate inter-tester and intra-tester reliability and parallel reliability between a visual assessment method and a method using a pachymeter for locating the mid-point of the patella in determining the medial/lateral patella orientation. Fifteen asymptomatic subjects were assessed and the mid-point of the patella was determined by both methods on two separate occasions two weeks apart. Inter-tester reliability was obtained by ANOVA and by intraclass correlation coefficient (ICC); intra-tester reliability was obtained by a paired t-test and ICC; and parallel reliability was obtained by Pearson's Correlation and ICC, for the measurement on the first and second evaluations. There was acceptable inter-tester agreement (p=0.490) and reliability for the visual inspection (ICC=0.747) and for the pachymeter (ICC=0.716) at the second evaluation. The inter-tester reliability in the first evaluation was unacceptable (visual ICC=0.604; pachymeter ICC=0.612). Although there was statistical similarity between measurements for the first and second evaluations for all testers, intra-tester reliability was not acceptable for both methods: visual (examiner 1 ICC=0.175; examiner 2 ICC=0.189; examiner 3 ICC=0.155) and pachymeter (examiner 1 ICC=0.214; examiner 2 ICC=0.246; examiner 3 ICC=0.069). Parallel reliability gave a perfect correlation at the first evaluation (r=0.828; p<0.001) and at the second (r=0.756; p<0.001) and reliability was between acceptable and very good (ICC=[0.748-0.813]). Both visual and pachymeter methods provide reliable and similar medial/lateral patella orientation and are reliable between different examiners, but the results between the two assessments at 2 weeks' interval demonstrated an unacceptable reliability.

  17. Influence of light-curing units and restorative materials on the micro hardness of resin cements

    Directory of Open Access Journals (Sweden)

    Kuguimiya Rosiane

    2010-01-01

    Full Text Available Aim: The aim of this study was to evaluate the effect of indirect restorative materials (IRMs and light-curing units (LCUs on the micro hardness of dual-cured resin cement. Materials and Methods: A total of 36 cylindrical samples (2 mm thick were prepared with dual-cured resin cement (Relyx ARC photo-activated with either a QTH (Optilight Plus for 40s or a LED (Radii light-curing unit for 65s. Photo-activation was performed through the 2-mm- thick IRMs and the samples were divided into six groups (n=6 according to the combination of veneering materials (without, ceramic and indirect resin and LCUs (QTH and LED. In the control group, the samples were light-cured with a QTH unit without the interposition of any restorative material. Vickers micro hardness test was performed on the top and bottom surfaces of each sample (load of 50 g for 15 secs. The data were statistically analyzed using a three-way ANOVA followed by Tukey x s post-hoc test ( P < 0.05. Results: There were no statistically significant differences on the top surface between the light curing-units ( P > 0.05; however, the LED provided greater hardness on the bottom surface when a ceramic material was used ( P < 0.05. The mean hardness in photo-activated samples, in which there was no interposition of indirect materials, was significantly greater ( P < 0.01. Conclusions: It may be concluded that the interposition of the restorative material decreased the micro hardness in the deeper cement layer. Such decrease, however, was lower when the ceramic was interposed and the cement light-cured with LED.

  18. Inter-tester Reliability of the Hand-held dynamometer and the Leg Extensor Power Rig applied on Patients after Total Hip Arthroplasty

    DEFF Research Database (Denmark)

    Mikkelsen, Lone Ramer; Mechlenburg, Inger; Petersen, Annemette Krintel

    strength and Leg Extensor Power Rig (LEPR) is a tool for measuring muscle power. OBJECTIVES: To test the inter-tester reliability of the HHD in hip abduction and the LEPR in Total Hip Arthroplasty (THA) patients. METHODS: Two groups each consisting 20 subjects were included. Mean age was 68.4 years. All...... subjects had THA surgery three months prior to testing. The subjects conducted two test sessions with HHD and LEPR, with two different testers, separated by a break of 1½ hour. We assessed the relative inter-tester reliability with Intraclass Correlation Coefficient (ICC) and the absolute reliability...... with Limits of Agreement (LOA). RESULTS: Inter-tester reliability for the HHD: There was no significant difference between the two testers (p=0.66) and the two tests (0.41); ICC=0.94 (95% CI: 0.86;0.97) ; LOA=±18 Newton. Inter-tester reliability for the LEPR: There was no significant difference between...

  19. Inter-tester Reliability of the Hand-held dynamometer and the Leg Extensor Power Rig applied on Patients after Total Hip Arthroplasty

    DEFF Research Database (Denmark)

    Mikkelsen, Lone Ramer; Petersen, Annemette Krintel; Mikkelsen, Søren Søndergaard

    and Leg Extensor Power Rig (LEPR) is a tool for measuring muscle power. Purpose / Aim of Study: To test the inter-tester reliability of the HHD and the LEPR in Total Hip Arthroplasty (THA) patients. Materials and Methods: Two groups each consisting 20 subjects were included. Mean age was 68.4 years. All...... subjects had THA surgery three months prior to testing. The subjects conducted two test sessions with HHD and LEPR, with two different testers, separated by a break of 1½ hour. We assessed the relative inter-tester reliability with Intraclass Correlation Coefficient (ICC) and the absolute reliability...... with Limits of Agreement (LOA). Findings / Results: Inter-tester reliability for the HHD: There was no significant difference between the two testers (p=0.66) and the two tests (0.41); ICC=0.94 (95% CI: 0.86;0.97) ; LOA=±18 Newton. Inter-tester reliability for the LEPR: There was no significant difference...

  20. A study on hardness behavior of geopolymer paste in different condition

    Science.gov (United States)

    Zainal, Farah Farhana; Hussin, Kamarudin; Rahmat, Azmi; Abdullah, Mohd Mustafa Al Bakri; Shamsudin, Shaiful Rizam

    2016-07-01

    This study has been conducted to understand the hardness behavior of geopolymer paste in different conditions; with and without being immersed in water. Geopolymer paste has been used nowadays as an alternative way to reduce global warming pollution by carbon dioxide (CO2) released to the air caused from the production of Ordinary Portland Cement (OPC). Geopolymer has many advantages such as high compressive strength, lower water absorption and lower porosity. Geopolymer paste in this study was made from a mixture of fly ash and alkaline activators. The alkaline activators that have been used were sodium hydroxide (NaOH) solution and sodium silicate (Na2SiO3) solution. Then the mixture was allowed to harden for 24hrs at ambient temperature and then placed in the oven for 24hrs with 60°C for the curing process. The hardness testing was conducted after a few months when the samples already achieved the optimum design. The samples were divided to two conditions; without immersion which was placed at ambient temperature (S1) and immersed in water for one week (S2). The samples then are divided into two at the center and testing was conducted into 4 parts which are part 1, part 2, part 3 and part 4. Various methods of non-destructively testing concrete and mortar have been in use for many years such as Vickers hardness test, Rockwell hardness test, Brinell hardness test and many more. The Rockwell hardness test method as defined in ASTM E-18 is the most commonly used hardness test method which is also used in this study. From the results, S1 has higher hardness value than S2 for all parts with the maximum value of S1 is 118.6 and the minimum value is 71.8. The maximum value of S2 is 114.4 and the minimum value is 0. The central part of the geopolymer paste also showed greater hardness values than the edge area of the samples.

  1. Hard coal; Steinkohle

    Energy Technology Data Exchange (ETDEWEB)

    Loo, Kai van de; Sitte, Andreas-Peter [Gesamtverband Steinkohle e.V. (GVSt), Herne (Germany)

    2015-07-01

    International the coal market in 2014 was the first time in a long time in a period of stagnation. In Germany, the coal consumption decreased even significantly, mainly due to the decrease in power generation. Here the national energy transition has now been noticable affected negative for coal use. The political guidances can expect a further significant downward movement for the future. In the present phase-out process of the German hard coal industry with still three active mines there was in 2014 no decommissioning. But the next is at the end of 2015, and the plans for the time after mining have been continued. [German] International war der Markt fuer Steinkohle 2014 erstmals seit langem wieder von einer Stagnation gekennzeichnet. In Deutschland ging der Steinkohlenverbrauch sogar deutlich zurueck, vor allem wegen des Rueckgangs in der Stromerzeugung. Hier hat sich die nationale Energiewende nun spuerbar und fuer die Steinkohlennutzung negativ ausgewirkt. Die politischen Weichenstellungen lassen fuer die Zukunft eine weitere erhebliche Abwaertsbewegung erwarten. Bei dem im Auslaufprozess befindlichen deutschen Steinkohlenbergbau mit noch drei aktiven Bergwerken gab es 2014 keine Stilllegung. Doch die naechste steht zum Jahresende 2015 an, und die Planungen fuer die Zeit nach dem Bergbau sind fortgefuehrt worden.

  2. The Effect of Mouthwashes on Surface Hardness of Dental Ceramics

    Directory of Open Access Journals (Sweden)

    Jafari K

    2014-09-01

    Full Text Available Statement of problem: The effect of different mouthrinses on the surface characteristics of ceramic materials is not documented. Objectives: The aim of this study was to determine the effect of three mouthrinses, containing either alcohol, hydrogen peroxide or fluoride, on microhardness of two dental ceramics, (Duceram love, IPS e.max Ceram. Materials and Methods: Eighty cylindrical disks were prepared and divided into eight experimental groups (n=10 for each group according to the ceramic material and storage solutions. The microhardness of each sample in all groups was recorded prior to testing. For each ceramic, three groups were immersed in one of the three mouthrinses for a total of 24 and 96 hours. The fourth group was immersed in distilled water as the control. At the end the specimens were taken out, rinsed, dried and tested using microhardness tester. Results: The results of the two-way ANOVA indicated that there was no interaction between media, time and materials (P>0.05. Microhardness of the ceramics was not adversely affected by immersion in the studied mouthrinses. Conclusions: The patients with porcelain restorations should be assured that using mouthrinses containing hydrogen peroxide, alcohol or fluoride do not damage the surface hardness of the porcelain.

  3. EFFECT OF Nb ELEMENT CONTENT IN U-Zr ALLOY ON HARDNESS, MICROSTRUCTURE AND PHASE FORMATION

    Directory of Open Access Journals (Sweden)

    Masrukan Masrukan

    2015-07-01

    Full Text Available EFFECT OF Nb ELEMENT CONTENT IN U-Zr-Nb ALLOY ON HARDNESS, MICROSTRUCTURE AND PHASE FORMATION. Experiments to determine the effect of Nb element in the U-Zr alloys on hardness, microstructure and phase formation has been done. The addition of Nb element would effect the hardness, microstructure and phase which formed. The U-Zr-Nb alloy was made with the variation of Nb 2%, 5% and 8% by melting in an electric arc melting furnace that equipped with water cooling and the argon atmosphere. The U-Zr-Nb alloy to be cut divided to some testing, such as hardness test, microstructure, and phase analysis. Hardness testing was done by Vickers hardness testing equipment, microstructure by an optical microscope, and diffraction pattern by XRD and phase analysis was done by GSAS. Hardness testing results showed that the addition of 2% to 5% Nb element in U-Zr alloys will increased in hardness, but the addition of Nb element over 5% the hardness was decreased. Observations the microstructure showed that the addition of 2% to 5%Nb element, grains were formed from fine into coarse. Phase analysis for diffraction pattern showed that the phase changed from αU and γU (Zr,Nbat 2% Nb to be αU, γU (Zr,Nb and δ1 (UZr2 phase at 5% and 8% Nb. Phase changes was followed by changes in its compositions. The composition of αU at 2% Nb was 40% increased to 81% at 5% Nb and decreased to 3.9% at 8% Nb. The composition of γU decreased from 59,86% to 14,91% with increased Nb from 2% to 5% and further increased to 52,74% at 8% Nb.   PENGARUH KADAR UNSUR Nb PADA PADUAN U-Zr-Nb TERHADAP SIFAT MEKANIK, MIKROSTRUKTUR DAN PEMBENTUKAN FASA. Percobaan untuk mengtahui pengaruh kadar Nb pada paduan U-Zr-Nb terhadap sifat mekanik, mikrostruktur dan pembentukan fasa telah dilakukan. Penambahan unsur Nb diduga akan mempengaruhi sifat mekanik, mikrosruktur, ketahanan korosi dan fasa yang terbentuk. Penambahan unsur Nb ke dalam paduan U-Zr dimaksudkan untuk memperluas daerah fasa gamma

  4. Correlation of impression removal force with elastomeric impression material rigidity and hardness.

    Science.gov (United States)

    Walker, Mary P; Alderman, Nick; Petrie, Cynthia S; Melander, Jennifer; McGuire, Jacob

    2013-07-01

    Difficult impression removal has been linked to high rigidity and hardness of elastomeric impression materials. In response to this concern, manufacturers have reformulated their materials to reduce rigidity and hardness to decrease removal difficulty; however, the relationship between impression removal and rigidity or hardness has not been evaluated. The purpose of this study was to determine if there is a positive correlation between impression removal difficulty and rigidity or hardness of current elastomeric impression materials. Light- and medium-body polyether (PE), vinylpolysiloxane (VPS), and hybrid vinyl polyether siloxane (VPES) impression materials were tested (n = 5 for each material/consistency/test method). Rigidity (elastic modulus) was measured via tensile testing of dumbbell-shaped specimens (Die C, ASTM D412). Shore A hardness was measured using disc specimens according to ASTM D2240-05 test specifications. Impressions were also made of a custom stainless steel model using a custom metal tray that could be attached to a universal tester to measure associated removal force. Within each impression material consistency, one-factor ANOVA and Tukey's post hoc analyses (α = 0.05) were used to compare rigidity, hardness, and removal force of the three types of impression materials. A Pearson's correlation (α = 0.05) was used to evaluate the association between impression removal force and rigidity or hardness. With medium-body materials, VPS exhibited significantly higher (p ≤ 0.05) rigidity and hardness than VPES or PE, while PE impressions required significantly higher (p ≤ 0.05) removal force than VPS or VPES impressions. With light-body materials, VPS again demonstrated significantly higher (p ≤ 0.05) hardness than VPES or PE, while the rigidity of the light-body materials did not significantly differ between materials (p > 0.05); however, just as with the medium-body materials, light-body PE impressions required significantly higher (p

  5. A new ankle laxity tester and its use in the measurement of the effectiveness of taping.

    Science.gov (United States)

    Kirk, T; Saha, S; Bowman, L S

    2000-12-01

    Damage to the lateral ligaments of the ankle, namely the anterior talofibular (ATFL) and the calcaneofibular (CFL) ligaments, is a frequently reported sports injury. The anterior drawer test is generally used to evaluate whether the ATFL has been torn, while the talar tilt test is used to determine if the CFL has been injured. Although these two manual tests are often utilized for quick diagnosis, they have been criticized because of their subjective nature and their inability to produce quantitative and reproducible results. A prototype ankle tester was manufactured that could measure the input force and torque, as well as the linear and angular deprivations for the anterior drawer test and the talar tilt test, respectively. This device was used to take readings on 10 human volunteers of a mean age of 21.6 years. This device was X-ray compatible, adjustable for varying patient sizes, relatively small, portable, and easy to operate. Testing was performed to determine how the stiffness of the ankle would respond to taping, and the effect of walking on the taped ankle. The overall mean anterior drawer was 5.93 mm and the mean talar tilt was 51.6 degrees for bare ankles using a force of 111 N (25 lbs) for the drawer and a torque of 16 N m for the tilt. Taping provided an average increase in stiffness of 11.3%, demonstrating that it did provide increased stability. However, statistically significant (Pmeasurements, and results show that the increase in stiffness due to taping did decrease after a short period of time.

  6. Intra-tester Reliability and Construct Validity of a Hip Abductor Eccentric Strength Test.

    Science.gov (United States)

    Brindle, Richard A; Ebaugh, D David; Milner, Clare E

    2017-11-15

    Side-lying hip abductor strength tests are commonly used to evaluate muscle strength. In a 'break' test the tester applies sufficient force to lower the limb to the table while the patient resists. The peak force is postulated to occur while the leg is lowering, thus representing the participant's eccentric muscle strength. However, it is unclear whether peak force occurs before or after the leg begins to lower. To determine intra-rater reliability and construct validity of a hip abductor eccentric strength test. Intra-rater reliability and construct validity study. Twenty healthy adults (26 ±6 years; 1.66 ±0.06 m; 62.2 ±8.0 kg) made two visits to the laboratory at least one week apart. During the hip abductor eccentric strength test, a hand-held dynamometer recorded peak force and time to peak force and limb position was recorded via a motion capture system. Intra-rater reliability was determined using intra-class correlation (ICC), standard error of measurement (SEM), and minimal detectable difference (MDD). Construct validity was assessed by determining if peak force occurred after the start of the lowering phase using a one-sample t-test. The hip abductor eccentric strength test had substantial intra-rater reliability (ICC(3,3) = 0.88; 95% confidence interval: 0.65-0.95), SEM of 0.9%BWh, and a MDD of 2.5%BWh. Construct validity was established as peak force occurred 2.1s (±0.6s; range 0.7s to 3.7s) after the start of the lowering phase of the test (p ≤ 0.001). The hip abductor eccentric strength test is a valid and reliable measure of eccentric muscle strength. This test may be used clinically to assess changes in eccentric muscle strength over time.

  7. Evaluation of light curing distance and mylar strips color on surface hardness of two different dental composite resins.

    Science.gov (United States)

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

    2014-01-01

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

  8. An Evaluation of Mechanical Properties with the Hardness of Building Steel Structural Members for Reuse by NDT

    Directory of Open Access Journals (Sweden)

    Masanori Fujita

    2016-10-01

    Full Text Available The reuse system proposed by the authors is one method to reduce the environmental burden in the structural field. As for reusable members, we take up building steel structures used for plants and warehouses. These buildings are assumed to be demolished within approximately 30 years or more for physical, architectural, economic, or social reasons in Japan. In this paper, the performance of steel structural members of a gable frame is evaluated with a non-destructive test for reuse. First, the flow to estimate mechanical properties of steel structural members such as tensile strength, yield strength, and elongation is shown via a non-destructive test. Next, tensile strength, yield strength, and elongation of steel structural members are estimated, with hardness measured with a portable ultrasonic hardness tester. Finally, the mechanical properties of steel structural members for reuse are estimated based on the proposed flow.

  9. A hard oxide semiconductor with a direct and narrow bandgap and switchable p-n electrical conduction.

    Science.gov (United States)

    Ovsyannikov, Sergey V; Karkin, Alexander E; Morozova, Natalia V; Shchennikov, Vladimir V; Bykova, Elena; Abakumov, Artem M; Tsirlin, Alexander A; Glazyrin, Konstantin V; Dubrovinsky, Leonid

    2014-12-23

    An oxide semiconductor (perovskite-type Mn2 O3 ) is reported which has a narrow and direct bandgap of 0.45 eV and a high Vickers hardness of 15 GPa. All the known materials with similar electronic band structures (e.g., InSb, PbTe, PbSe, PbS, and InAs) play crucial roles in the semiconductor industry. The perovskite-type Mn2 O3 described is much stronger than the above semiconductors and may find useful applications in different semiconductor devices, e.g., in IR detectors. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Research results of hard photon technology have been summarized as a part of novel technology development highly utilizing the quantum nature of photon. Hard photon technology refers to photon beam technologies which use photon in the 0.1 to 200 nm wavelength region. Hard photon has not been used in industry due to the lack of suitable photon sources and optical devices. However, hard photon in this wavelength region is expected to bring about innovations in such areas as ultrafine processing and material synthesis due to its atom selective reaction, inner shell excitation reaction, and spatially high resolution. Then, technological themes and possibility have been surveyed. Although there are principle proposes and their verification of individual technologies for the technologies of hard photon generation, regulation and utilization, they are still far from the practical applications. For the photon source technology, the laser diode pumped driver laser technology, laser plasma photon source technology, synchrotron radiation photon source technology, and vacuum ultraviolet photon source technology are presented. For the optical device technology, the multi-layer film technology for beam mirrors and the non-spherical lens processing technology are introduced. Also are described the reduction lithography technology, hard photon excitation process, and methods of analysis and measurement. 430 refs., 165 figs., 23 tabs.

  11. Growth kinetics of boride layers formed on 99.0% purity nickel

    Indian Academy of Sciences (India)

    The boride layer was characterized by optical microscopy, X-ray diffraction technique and micro-Vickers hardness tester. X-ray diffraction analysis revealed the existence of NiB, Ni2B, Ni3B and Ni4B3 compounds at the surface of borided Nickel 201 alloy. The thickness of the boride layer increased with an increase in the ...

  12. Investigation of diffusion kinetics of plasma paste borided AISI 8620 ...

    Indian Academy of Sciences (India)

    ... diffraction, Vickers micro-hardness tester and the growth kinetics of the boride layers. X-ray diffraction analysis of boride layers on the surface of the steel revealed FeB and Fe2B phases. Depending on temperature and layer thickness, the activation energies of boron in steel were found to be 124.7 kJ/mol for 100% B2O3.

  13. Manganese mono-boride, an inexpensive room temperature ferromagnetic hard material

    Science.gov (United States)

    Ma, Shuailing; Bao, Kuo; Tao, Qiang; Zhu, Pinwen; Ma, Teng; Liu, Bo; Liu, Yazhou; Cui, Tian

    2017-03-01

    We synthesized orthorhombic FeB-type MnB (space group: Pnma) with high pressure and high temperature method. MnB is a promising soft magnetic material, which is ferromagnetic with Curie temperature as high as 546.3 K, and high magnetization value up to 155.5 emu/g, and comparatively low coercive field. The strong room temperature ferromagnetic properties stem from the positive exchange-correlation between manganese atoms and the large number of unpaired Mn 3d electrons. The asymptotic Vickers hardness (AVH) is 15.7 GPa which is far higher than that of traditional ferromagnetic materials. The high hardness is ascribed to the zigzag boron chains running through manganese lattice, as unraveled by X-ray photoelectron spectroscopy result and first principle calculations. This exploration opens a new class of materials with the integration of superior mechanical properties, lower cost, electrical conductivity, and fantastic soft magnetic properties which will be significant for scientific research and industrial application as advanced structural and functional materials.

  14. Manganese mono-boride, an inexpensive room temperature ferromagnetic hard material.

    Science.gov (United States)

    Ma, Shuailing; Bao, Kuo; Tao, Qiang; Zhu, Pinwen; Ma, Teng; Liu, Bo; Liu, Yazhou; Cui, Tian

    2017-03-06

    We synthesized orthorhombic FeB-type MnB (space group: Pnma) with high pressure and high temperature method. MnB is a promising soft magnetic material, which is ferromagnetic with Curie temperature as high as 546.3 K, and high magnetization value up to 155.5 emu/g, and comparatively low coercive field. The strong room temperature ferromagnetic properties stem from the positive exchange-correlation between manganese atoms and the large number of unpaired Mn 3d electrons. The asymptotic Vickers hardness (AVH) is 15.7 GPa which is far higher than that of traditional ferromagnetic materials. The high hardness is ascribed to the zigzag boron chains running through manganese lattice, as unraveled by X-ray photoelectron spectroscopy result and first principle calculations. This exploration opens a new class of materials with the integration of superior mechanical properties, lower cost, electrical conductivity, and fantastic soft magnetic properties which will be significant for scientific research and industrial application as advanced structural and functional materials.

  15. Microstructural and hardness behavior of graphene-nanoplatelets/aluminum composites synthesized by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Pérez-Bustamante, R. [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes No. 120, C.P. 31109 Chihuahua, Chih. (Mexico); Bolaños-Morales, D.; Bonilla-Martínez, J. [Universidad Autónoma de Chihuahua (UACH), Facultad de Ingeniería, Circuito No. 1 Nuevo Campus Universitario, C.P. 31125 Chihuahua, Chih. (Mexico); Estrada-Guel, I. [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes No. 120, C.P. 31109 Chihuahua, Chih. (Mexico); Martínez-Sánchez, R., E-mail: roberto.martinez@cimav.edu.mx [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes No. 120, C.P. 31109 Chihuahua, Chih. (Mexico)

    2014-12-05

    Highlights: • Pure aluminum was reinforced with graphene-platelets by using mechanical milling. • The composites were studied after sintering condition. • Milling time and graphene-platelet enhance the mechanical behavior of the composites. - Abstract: Graphene can be considered as an ideal reinforcement for the production of composites due to its outstanding mechanical properties. These characteristics offer an increased opportunity for their study in the production of metal matrix composites (MMCs). In this research, the studied composites were produced by mechanical alloying (MA). The employed milling times were of 1, 3 and 5 h. GNPs were added in 0.25, 0.50 and 1.0 wt% into an aluminum powder matrix. Milled powders were cold consolidated and subsequently sintered. Composites were microstructurally characterized with Raman spectroscopy and electron microscopy and X-ray diffraction. The hardness behavior in composites was evaluated with a Vickers micro-hardness test. A homogeneous dispersion of graphene during MA and the proper selection of sintering conditions were considered to produce optimized composites. The obtained results with electron microscopy indicate a homogeneous dispersion of GNPs into the aluminum matrix. Analyses showed GNPs edges where the structure of the graphene layers conserved after MA is observed.

  16. Effect of solution treatment on microstructure and hardness of rheo-forming AZ91-Y alloy

    Directory of Open Access Journals (Sweden)

    Zhi-wei Wang

    2016-11-01

    Full Text Available The microstructure and hardness of rheo-forming AZ91-Y alloy before and after solution treatment (ST have been investigated by means of optical microscope (OM, scanning electron microscope (SEM equipped with energy dispersive spectroscopy (EDS, X-ray diffraction (XRD and Vickers. The experimental results showed that the β-Mg17Al12 phase of alloy was nearly dissolved after ST for 5 min. With the increasing of ST duration to 28 h, both the primary and secondarily solidified α-Mg grains faded away. At the same time, the alloy exhibited a much smoother surface due to the diffusion of solute atoms (Al. During ST, the thermal stable phase of Al2Y produced by ultrasonic vibration retained its size and morphology. As the ST duration was increased, the alloy hardness decreased sharply at first, and then gradually reached a minimum level. The alloy’s appropriate ST duration at 410 °C was approximately 28 h.

  17. Surface roughness and hardness of a composite resin: influence of finishing and polishing and immersion methods

    Directory of Open Access Journals (Sweden)

    Ana Luísa Botta Martins de Oliveira

    2010-09-01

    Full Text Available This study evaluated the finishing and polishing effect on the surface roughness and hardness of the Filtek Supreme XT, in fluoride solutions. Specimens were prepared (n = 140 with half of the samples finished and polished with Super-Snap® disks. The experimental groups were divided according to the presence or absence of finishing and polishing and immersion solutions (artificial saliva, sodium fluoride solution at 0.05% - manipulated, Fluordent Reach, Oral B, Fluorgard. The specimens remained immersed in artificial saliva for 24 hours and were then subjected to initial analysis (baseline of surface roughness and Vickers microhardness. Next, they were immersed in different fluoride solutions for 1 min/day, for 60 days. Afterwards, a new surface roughness and microhardness reading was conducted. The data were submitted to a two-way ANOVA and Tukey's test (5% significance level. For the comparison of mean roughness and hardness at baseline and after 60 days, the paired Student t test was used. The results showed that the surface roughness and microhardness of the Filtek Supreme XT were influenced by the finishing and polishing procedure, independently of the immersion methods.

  18. Effect of light-curing method and indirect veneering materials on the Knoop hardness of a resin cement

    Directory of Open Access Journals (Sweden)

    Nelson Tetsu Iriyama

    2009-06-01

    Full Text Available This study evaluated the Knoop hardness of a dual-cured resin cement (Rely-X ARC activated solely by chemical reaction (control group or by chemical / physical mode, light-cured through a 1.5 mm thick ceramic (HeraCeram or composite (Artglass disc. Light curing was carried out using conventional halogen light (XL2500 for 40 s (QTH; light emitting diodes (Ultrablue Is for 40 s (LED; and Xenon plasma arc (Apollo 95E for 3 s (PAC. Bovine incisors had their buccal face flattened and hybridized. On this surface a rubber mold (5 mm in diameter and 1 mm in height was bulk filled with the resin cement. A polyester strip was seated for direct light curing or through the discs of veneering materials. After dry storage in the dark (24 h 37°C, the samples (n = 5 were sectioned for hardness (KHN measurements, taken in a microhardness tester (50 gF load 15 s. The data were statistically analyzed by ANOVA and Tukey's test (α = 0.05. The cement presented higher Knoop hardness values with Artglass for QTH and LED, compared to HeraCeram. The control group and the PAC/Artglass group showed lower hardness values compared to the groups light-cured with QTH and LED. PAC/HeraCeram resulted in the worst combination for cement hardness values.

  19. Scheduling Semiconductor Multihead Testers Using Metaheuristic Techniques Embedded with Lot-Specific and Configuration-Specific Information

    OpenAIRE

    Yi-Feng Hung; Chi-Chung Wang; Gen-Han Wu

    2013-01-01

    In the semiconductor back-end manufacturing, the device test central processing unit (CPU) is most costly and is typically the bottleneck machine at the test plant. A multihead tester contains a CPU and several test heads, each of which can be connected to a handler that processes one lot of the same device. The residence time of a lot is closely related to the product mix on test heads, which increases the complexity of this problem. It is critical for the test scheduling problem to reduce C...

  20. Evaluation of hardness and surface roughness of two maxillofacial silicones following disinfection

    Directory of Open Access Journals (Sweden)

    Marcelo Coelho Goiato

    2009-03-01

    Full Text Available The purpose of this study was to evaluate the Shore A hardness and surface roughness of two silicones for maxillofacial prosthetic treatment, under the influence of chemical disinfection and storage. Twenty-eight specimens were obtained, half of which were made of Silastic MDX 4-4210 silicone and, the other half were made of Silastic 732 RTV silicone. The specimens were divided into four groups: Silastic 732 RTV and MDX 4-4210 with disinfection 3 times a week with Efferdent tablets and the same materials without disinfection. The hardness of the materials was analyzed with a Shore A Durometer. The surface roughness was established by a digital portable roughness tester, initially and 2 months after the confection of the specimens. A variance test was applied (2-way ANOVA, followed by Tukey test (the level of significance was set at 1%. The storage time factor statistically influenced (p < 0.01 the materials' properties of hardness and roughness. MDX 4-4210 (28.59 Shore A, 0.789 Ra presented higher values than Silastic 732 RTV (18.08 Shore A, 0.656 Ra for both properties. Regarding the disinfection period, there was no significant difference in any of the materials tested.

  1. Tactile Perception of Roughness and Hardness to Discriminate Materials by Friction-Induced Vibration.

    Science.gov (United States)

    Ding, Shuyang; Pan, Yunlu; Tong, Mingsi; Zhao, Xuezeng

    2017-11-28

    The human fingertip is an exquisitely powerful bio-tactile sensor in perceiving different materials based on various highly-sensitive mechanoreceptors distributed all over the skin. The tactile perception of surface roughness and material hardness can be estimated by skin vibrations generated during a fingertip stroking of a surface instead of being maintained in a static position. Moreover, reciprocating sliding with increasing velocities and pressures are two common behaviors in humans to discriminate different materials, but the question remains as to what the correlation of the sliding velocity and normal load on the tactile perceptions of surface roughness and hardness is for material discrimination. In order to investigate this correlation, a finger-inspired crossed-I beam structure tactile tester has been designed to mimic the anthropic tactile discrimination behaviors. A novel method of characterizing the fast Fourier transform integral (FFT) slope of the vibration acceleration signal generated from fingertip rubbing on surfaces at increasing sliding velocity and normal load, respectively, are defined as k v and k w , and is proposed to discriminate the surface roughness and hardness of different materials. Over eight types of materials were tested, and they proved the capability and advantages of this high tactile-discriminating method. Our study may find applications in investigating humanoid robot perceptual abilities.

  2. Tactile Perception of Roughness and Hardness to Discriminate Materials by Friction-Induced Vibration

    Directory of Open Access Journals (Sweden)

    Shuyang Ding

    2017-11-01

    Full Text Available The human fingertip is an exquisitely powerful bio-tactile sensor in perceiving different materials based on various highly-sensitive mechanoreceptors distributed all over the skin. The tactile perception of surface roughness and material hardness can be estimated by skin vibrations generated during a fingertip stroking of a surface instead of being maintained in a static position. Moreover, reciprocating sliding with increasing velocities and pressures are two common behaviors in humans to discriminate different materials, but the question remains as to what the correlation of the sliding velocity and normal load on the tactile perceptions of surface roughness and hardness is for material discrimination. In order to investigate this correlation, a finger-inspired crossed-I beam structure tactile tester has been designed to mimic the anthropic tactile discrimination behaviors. A novel method of characterizing the fast Fourier transform integral (FFT slope of the vibration acceleration signal generated from fingertip rubbing on surfaces at increasing sliding velocity and normal load, respectively, are defined as kv and kw, and is proposed to discriminate the surface roughness and hardness of different materials. Over eight types of materials were tested, and they proved the capability and advantages of this high tactile-discriminating method. Our study may find applications in investigating humanoid robot perceptual abilities.

  3. Composition, microstructure, hardness, and wear properties of high-speed steel rolls

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.W.; Lee, H.C. [Kangwon Industries, Ltd., Pohang (Korea, Republic of). Roll Mfg. Div.; Lee, S. [Pohang Univ. of Science and Technology (Korea, Republic of). Center for Advanced Aerospace Materials

    1999-02-01

    The effects of alloying elements on the microstructural factors, hardness, and wear properties of four high-speed steel (HSS) rolls fabricated by centrifugal casting were investigated. A hot-rolling simulation test was carried out using a high-temperature wear tester capable of controlling speed, load, and temperature. The test results revealed that the HSS roll containing a larger amount of vanadium showed the best wear resistance because it contained a number of hard MC-type carbides. However, it showed a very rough roll surface because of cracking along cell boundaries, the preferential removal of the matrix, and the sticking of the rolled material onto the roll surface during the wear process, thereby leading to an increase in the friction coefficient and rolling force. In order to improve wear resistance with consideration to surface roughness, it is suggested that a reduction in the vanadium content, an increase in solid-solution hardening by adding alloying elements, an increase in secondary hardening by precipitation of fine carbides in the matrix, and formation of refined prior austenite grains by preaustenitization treatment be employed to strengthen the matrix, which can hold hard carbides in it.

  4. Hard-phase engineering in hard/soft nanocomposite magnets

    Science.gov (United States)

    Poudyal, Narayan; Rong, Chuanbing; Vuong Nguyen, Van; Liu, J. Ping

    2014-03-01

    Bulk SmCo/Fe(Co) based hard/soft nanocomposite magnets with different hard phases (1:5, 2:17, 2:7 and 1:3 types) were fabricated by high-energy ball-milling followed by a warm compaction process. Microstructural studies revealed a homogeneous distribution of bcc-Fe(Co) phase in the matrix of hard magnetic Sm-Co phase with grain size ⩽20 nm after severe plastic deformation and compaction. The small grain size leads to effective inter-phase exchange coupling as shown by the single-phase-like demagnetization behavior with enhanced remanence and energy product. Among the different hard phases investigated, it was found that the Sm2Co7-based nanocomposites can incorporate a higher soft phase content, and thus a larger reduction in rare-earth content compared with the 2:17, 1:5 and 1:3 phase-based nanocomposite with similar properties. (BH)max up to 17.6 MGOe was obtained for isotropic Sm2Co7/FeCo nanocomposite magnets with 40 wt% of the soft phase which is about 300% higher than the single-phase counterpart prepared under the same conditions. The results show that hard-phase engineering in nanocomposite magnets is an alternative approach to fabrication of high-strength nanocomposite magnets with reduced rare-earth content.

  5. Effect of disinfectants on the hardness and roughness of reline acrylic resins.

    Science.gov (United States)

    Azevedo, Andrea; Machado, Ana Lucia; Vergani, Carlos Eduardo; Giampaolo, Eunice Teresinha; Pavarina, Ana Cláudia; Magnani, Romeo

    2006-01-01

    Potential effects on hardness and roughness of a necessary and effective disinfecting regimen (1% sodium hypocholorite and 4% chlorhexidine) were investigated for two hard chairside reline resins versus a heat-polymerizing denture base acrylic resin. Two standard hard chairside reliners (Kooliner and Duraliner II), one heat-treated chairside reliner (Duraliner II +10 minutes in water at 55 degrees C), and one standard denture base material (Lucitone 550) were exposed to two disinfecting solutions (1% sodium hypochlorite; 4% chlorhexidine gluconate), and tested for two surface properties [Vickers hardness number (VHN, kg/mm(2)); Roughness (Ra, microm)] for different times and conditions (1 hour after production, after 48 hours at 37 +/- 2 degrees C in water, after two disinfection cycles, after 7 days in disinfection solutions, after 7 days in water only). For each experimental condition, eight specimens were made from each material. Data were analyzed by analysis of variance followed by Tukey's test, and Student's t-test (p= 0.05). For Kooliner (from 6.2 +/- 0.3 to 6.5 +/- 0.5 VHN) and Lucitone 550 (from 16.5 +/- 0.4 to 18.4 +/- 1.7 VHN), no significant changes in hardness were observed either after the disinfection or after 7 days of immersion, regardless of the disinfectant solution used. For Duraliner II (from 4.0 +/- 0.1 to 4.2 +/- 0.1 VHN), with and without heat treatment, a small but significant increase in hardness was observed for the specimens immersed in the disinfectant solutions for 7 days (from 4.3 +/- 0.2 to 4.8 +/- 0.5 VHN). All materials showed no significant change in roughness (Kooliner: from 0.13 +/- 0.05 to 0.48 +/- 0.24 microm; Duraliner II, with and without heat treatment: from 0.15 +/- 0.04 to 0.29 +/- 0.07 microm; Lucitone 550: from 0.44 +/- 0.19 to 0.49 +/- 0.15 microm) after disinfection and after storage in water for 7 days. The disinfectant solutions, 1% sodium hypochlorite and 4% chlorhexidine gluconate, caused no apparent damage on

  6. Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period.

    Science.gov (United States)

    Erdemir, Ugur; Yildiz, Esra; Eren, Meltem Mert; Ozel, Sevda

    2013-01-01

    This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group). For the control groups, the specimens were stored in distilled water for 24 hours at 37°C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05). Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (psports and energy drinks after a 1-month evaluation period (psports and energy drinks on the surface hardness of a restorative material depends on the duration of exposure time, and the composition of the material.

  7. Relating the octane numbers of fuels to ignition delay times measured in an ignition quality tester (IQT)

    KAUST Repository

    Naser, Nimal

    2016-09-21

    A methodology for estimating the octane index (OI), the research octane number (RON) and the motor octane number (MON) using ignition delay times from a constant volume combustion chamber with liquid fuel injection is proposed by adopting an ignition quality tester. A baseline data of ignition delay times were determined using an ignition quality tester at a charge pressure of 21.3 bar between 770 and 850 K and an equivalence ratio of 0.7 for various primary reference fuels (PRFs, mixtures of isooctane and n-heptane). Our methodology was developed using ignition delay times for toluene reference fuels (mixtures of toluene and n-heptane). A correlation between the OI and the ignition delay time at the initial charge temperature enabled the OI of non-PRFs to be predicted at specified temperatures. The methodology was validated using ignition delay times for toluene primary reference fuels (ternary mixtures of toluene, iso-octane, and n-heptane), fuels for advanced combustion engines (FACE) gasolines, and certification gasolines. Using this methodology, the RON, the MON, and the octane sensitivity were estimated in agreement with values obtained from standard test methods. A correlation between derived cetane number and RON is also provided. (C) 2016 Elsevier Ltd. All rights reserved.

  8. Assessing the viscoelastic properties of upper trapezius muscle: Intra- and inter-tester reliability and the effect of shoulder elevation.

    Science.gov (United States)

    Liu, C L; Feng, Y N; Zhang, H Q; Li, Y P; Zhu, Y; Zhang, Z J

    2017-10-19

    Increasing stiffness in the upper trapezius muscle may contribute to imbalance of scapular motion, and result in shoulder and neck discomfort during shoulder flexion. Therefore, it is essential to quantify upper trapezius stiffness in various shoulder positions in order to aid in the prevention of these disorders and to optimize rehabilitation. The objectives of the present study were to examine the intra and inter-tester reliability of MyotonPRO device in measuring upper trapezius stiffness and its ability to determine changes in stiffness during shoulder flexion. Twenty healthy male subjects (mean age: 28.3±4.8 years) were studied. The stiffness of upper trapezius was quantified using the MyotonPRO device. The results revealed excellent intra and inter-tester reliability for measuring upper trapezius stiffness with the shoulder in a neutral position, and also found a 14.2% increase in stiffness upon shoulder flexion between 0° and 60° of flexion. Minimal detectable change (MDC) was 26.3 N/m. Our findings indicate that MyotonPRO device is a feasible tool to quantify upper trapezius stiffness as well as changes in muscle stiffness. Thus, it is important to assess the changes in upper trapezius muscle stiffness due to pathology or treatments for future studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Change detection technique for muscle tone during static stretching by continuous muscle viscoelasticity monitoring using wearable indentation tester.

    Science.gov (United States)

    Okamura, Naomi; Kobayashi, Yo; Sugano, Shigeki; Fujie, Masakatsu G

    2017-07-01

    Static stretching is widely performed to decrease muscle tone as a part of rehabilitation protocols. Finding out the optimal duration of static stretching is important to minimize the time required for rehabilitation therapy and it would be helpful for maintaining the patient's motivation towards daily rehabilitation tasks. Several studies have been conducted for the evaluation of static stretching; however, the recommended duration of static stretching varies widely between 15-30 s in general, because the traditional methods for the assessment of muscle tone do not monitor the continuous change in the target muscle's state. We have developed a method to monitor the viscoelasticity of one muscle continuously during static stretching, using a wearable indentation tester. In this study, we investigated a suitable signal processing method to detect the time required to change the muscle tone, utilizing the data collected using a wearable indentation tester. By calculating a viscoelastic index with a certain time window, we confirmed that the stretching duration required to bring about a decrease in muscle tone could be obtained with an accuracy in the order of 1 s.

  10. Effect of sintering temperature on physical properties & hardness of CoCrMo alloys fabricated by metal injection moulding process

    Science.gov (United States)

    Ridhwan Abdullah, Ahmad; Aidah Nabihah Dandang, Nur; Zalikha Khalil, Nur; Harun, Wan Sharuzi Wan

    2017-10-01

    Metal Injection Moulding (MIM) process is one of the Powder Metallurgy manufacturing techniques utilised to produce Cobalt Chromium Molybdenum (CoCrMo) compacts. The objective of this study is to determine physical properties and hardness of CoCrMo alloy compact sintered at three different sintering temperature at the similar soaking time. At the beginning, sample were fabricated by using Injection Moulding machine. Cobalt Chrome Molybdenum (CoCrMo) metal powder was selected for this study. A morphological study was conducted using optical microscope (OM) and micro-Vickers hardness testing. From the result obtained, it shows upward trend either on the hardness or physical properties of the samples. CoCrMo sintered compact become harder and volume of pores on surface become less due to the increase on sintering temperature. However, effect of increasing sintering temperature shows significant shrinkage of the sample, beginning losses in dimensional accuracy. It is discovered that a little change in sintering temperature gives significant impact on the microstructure, physical, mechanical of the alloy.

  11. Continuous FEM simulation of the nanoindentation. Actual indenter tip geometries, material elastoplastic deformation laws and universal hardness

    Energy Technology Data Exchange (ETDEWEB)

    Bouzakis, K.D.; Michailidis, N.; Hadjiyiannis, S.; Skordaris, G. [Mechanical Engineering Dept., Aristoteles Univ. of Thessaloniki (Greece); Erkens, G. [CemeCon AG, Wuerselen (Germany)

    2002-09-01

    The precise knowledge of materials mechanical properties is always a core issue in every technical application. Through a developed finite elements method (FEM) continuous simulation of the nanoindentation, the applied force course versus the penetration depth is adequately simulated during the loading and unloading phases of this test, and the corresponding material stress-strain curves, as well as the universal hardness, are stepwise defined. Furthermore, the actual tip geometries of various indenters are approached and through equivalent magnitudes described. The results show that the defined material elastoplastic deformation characteristics are independent of the indenter type, as Vickers or Berkovich, since the existing indenter tip form deviations from their ideal geometry are considered. Furthermore, using the developed FEM-based nanoindentation simulation, the influence of the indenter tip geometry on the defined constitutive laws and the universal hardness is sufficiently elucidated. Various materials stress-strain curves and universal hardness courses versus the indentation depth, determined by means of the developed procedure, are presented. (orig.)

  12. Comparative study on the lateral run-out of friction surfaces measurement of brake discs using a brake roller tester and a dial gauge

    Directory of Open Access Journals (Sweden)

    Toma Marius

    2017-01-01

    Full Text Available Brake system diagnosis is one of the most common and necessary technical operations applied to the car, regardless of its type and operating phases. Measuring the diagnostic parameters on a roller brake tester is a fast operation with no disassembly necessary. Measuring the run-out of friction surfaces of brake discs with a dial gauge is an action that requires more extensive preparatory operations but it offers a high accuracy of the results. The paper aims to analyze the correlation between the dial gauge measured values and the diagnostic obtained using the brake roller tester.

  13. Chemical hardness and density functional theory

    Indian Academy of Sciences (India)

    Keywords. Hardness; softness; hard & soft acids bases (HSAB); principle of maximum hardness (PMH) density functional theory (DFT). Abstract. The concept of chemical hardness is reviewed from a personal point of view. Author Affiliations. Ralph G Pearson1. Chemistry Department, University of California, Santa Barbara, ...

  14. The effect of human blood on the setting and surface micro-hardness of calcium silicate cements.

    Science.gov (United States)

    Song, Minju; Yue, Wonyoung; Kim, Soyeon; Kim, Wooksung; Kim, Yaelim; Kim, Jeong-Woong; Kim, Euiseong

    2016-11-01

    The purpose of the present study was to evaluate the effects of human blood on the setting and microhardness of calcium silicate cements. Three types of silicate-based cements were used: ProRoot MTA (PMTA), OrthoMTA (OMTA), and RetroMTA (RMTA). Mixed cement was placed into polyethylene molds with lengths of 2 and 4 mm. After storage for 4 days under three different storage conditions, i.e., saline, saline after 5 min of human blood, and human blood, the polyethylene molds were removed. With the specimens set, the surface microhardness was measured using a Vickers microhardness tester, crystalline structure was analyzed with X-ray diffraction (XRD), and the surface characteristics were examined with scanning electron microscopy (SEM). All specimens of 4 mm in length were set with all materials, and the blood groups exhibited lower microhardnesses than did the saline groups (p blood, the numbers of specimens that set were significantly different across the materials (p blood group exhibited reduced microhardness. XRD showed changes of crystalline structure in the PMTA and OMTA blood group, whereas RMTA did not. SEM analysis revealed more rounded and homogeneous structures and demonstrated a clear lack of acicular or needle-like crystals in the PMTA and OMTA blood groups, while RMTA did not reveal substantial differences between the saline- and blood-stored groups. Blood contamination detrimentally affected the surface microhardnesses of all materials; furthermore, among the 2-mm specimens, blood contamination interfered with normal setting. Therefore, RMTA might be a more suitable choice when blood contamination is unavoidable due to limited depth. Clinical relevance RetroMTA might be a more suitable choice in situations in which blood contamination is unavoidable.

  15. The remineralization potential of cocoa (Theobroma cacao bean extract to increase the enamel micro hardness

    Directory of Open Access Journals (Sweden)

    Sulistianingsih Sulistianingsih

    2017-08-01

    Full Text Available Introduction: Remineralization is the process of returning mineral ions into a hydroxyapatite structure characterized by mineral deposition on the enamel surface. The presence of mineral deposition would affect the micro hardness of tooth enamel. The use of fluorine as remineralization agent with side effects such as fluorosis. Cocoa bean extract contains theobromin that can be used as an alternative remineralization ingredients. The objectives was to determine micro hardness email after remineralization using cocoa bean extract as natural material and to compare with fluorine use as synthetic material. Methods: Thirty-six maxillary first premolar tooth crown was cut and planted in the epoxy resin. Teeth were then immersed in demineralization solution at pH 4 for 6 hours. The sample were divided into 2 groups, 18 for the fluorine group and the remaining group of cocoa extract. Vickers microhardness test was used before treatment, after demineralized and after remineralization. Results: Enamel microhardness value before treatment in the fluorine group average value was 376.17 VHN and the cocoa extract group was 357.33 VHN. After demineralization in fluorine group was 268,13 VHN and cocoa extract group was 235,93 VHN. After remineralization in fluorine group was 321,08 VHN and cocoa extract group was 293,86 VHN. The results of the analysis showed that the level of micro hardness email after remineralization was not significantly different in two groups (p > 0.05. Conclusions: Cocoa extract is able to increase the microhardness of enamel so it can act as a substitution for fluorine remineralization.

  16. Hardness and surface roughness of reline and denture base acrylic resins after repeated disinfection procedures.

    Science.gov (United States)

    Machado, Ana Lucia; Breeding, Larry C; Vergani, Carlos Eduardo; da Cruz Perez, Luciano Elias

    2009-08-01

    Microwave irradiation and immersion in chemical solutions have been recommended for denture disinfection. However, the effect of these procedures on the surface characteristics of denture base and reline resins has not been completely evaluated. The purpose of this study was to evaluate the effect of microwave and chemical disinfection on the Vickers hardness (VHN) and surface roughness (Ra, microm) of 2 hard chairside reline resins (Kooliner, DuraLiner II), and 1 heat-polymerizing denture base resin (Lucitone 550). Specimens (12 x 12 x 3 mm) were divided into 2 control and 4 test groups (n=8). Hardness and roughness measurements were performed after: polymerization and immersion in water (37 degrees C) for 7 days (controls), or repeated exposure to disinfection by immersion in sodium perborate (50 degrees C/10 min) or microwave irradiation (650 W/6 min). Measurements of surface roughness (Ra, microm) and hardness (kg/mm(2)) were analyzed using 3-way ANOVA and Tukey's Honestly Significant Difference (HSD) test (alpha=.05). Microwave and chemical disinfection increased the mean (SD) hardness of Kooliner (from 4.1 to 7.5 kg/mm(2)) and DuraLiner II (from 2.6 to 5.6 kg/mm(2)), whereas Lucitone 550 (14.4 kg/mm(2)) remained unaffected. Disinfection by immersion in sodium perborate increased the surface roughness of DuraLiner II (from 0.13 to 0.26 microm) and Kooliner (from 0.16 to 0.26 microm), regardless of the number of cycles. For Lucitone 550, an increase in roughness was observed after 2 cycles of chemical disinfection (from 0.12 to 0.26 microm). Two cycles of microwave disinfection increased the roughness of both reline resins (DuraLiner II: from 0.13 to 0.22 microm; Kooliner: from 0.16 to 0.24 microm), whereas repeated microwave disinfection increased the roughness of DuraLiner II (from 0.11 to 0.25 microm). Disinfection by immersion in sodium perborate or microwave irradiation did not adversely affect the hardness of all materials evaluated. The effect of both

  17. Differences between micro-hardness affected dentin after mechanical or chemo-mechanical infected dentin disposal (laboratory experiment)

    Science.gov (United States)

    Ihsani, V.; Nursasongko, B.; Djauharie, N.

    2017-08-01

    The concept of conserving healthy tooth structures during cavity preparation has gained popularity with chemo-mechanical caries removal. This study compared three methods of caries removal using: a chemo-mechanical caries removal papain gel; Papacarie® (these contain natural ingredients, mainly papain enzyme); and mechanical preparation with a bur rotary instrument. The purpose of this study was to compare affected dentin micro-hardness after removal of infected dentin with mechanical and chemo-mechanical techniques. Twenty-seven permanent molar teeth were randomly divided into three groups receiving removal of infected dentin. These were: Group 1: chemo-mechanical technique using papain gel; Group 2: chemo-mechanical technique using Papacarie® Group 3: mechanical technique using a bur rotary instrument. Each group was tested using Knoop Micro-hardness tester, and the data were submitted to one way ANOVA and Post-hoc Tukey test. There is a significant difference between Groups 1 and 3, and Groups 2 and 3, p = 0.000. However, there is no significant difference between Groups 1 and 2, p = 1.000. Affected dentin micro-hardness after removal of infected dentin with a bur rotary tool is higher than after use of the papain gel or Papacarie®. Affected dentin micro-hardness after removal of infected dentin with Papacarie® and papain gel give almost the same result.

  18. Effect of heat treatments on hardness and precipitation in 2.25Cr-1Mo-NiNb stabilized ferritic steel

    Energy Technology Data Exchange (ETDEWEB)

    Akhter, J.I.; Ahmad, M.; Shaikh, M.A. [Paakistan inst. of Nuclear Science and Technology, Islamabad (pakistan). Nuclear Physics Div.; Ehrlich, K. [Kernforschungszentrum Karlsruhe GmbH (Germany). Inst. fuer Material- und Festkoerperforschung 1 - Teilinstitut Kernbrennstoffe

    1996-05-15

    Investigations have been carried out in order to specify a heat treatment for the Nb stabilised 2.25Cr-1Mo steel and to study the effects of aging at 475{sup o}C, the temperature at which embrittlement occurs in the unstabilised material. Samples were austenised at temperatures over the range 950-1150{sup o}C for 1hr and 10hrs and then air cooled; tempering was carried out in the range 470-800{sup o}C for 1-100hrs and aging at 475{sup o}C for up to 1000hrs. Electron micrographs and summarised results of grain size measurements, Vicker`s hardness, and quantitative analyses of precipitates are presented. No segregation was observed of those trace elements such as P and S which cause embrittlement in the unstabilised material. Segregation might occur, however, with longer aging and a higher temperature, as has been observed by previous authors in 2.25Cr-1Mo-V steel. (UK).

  19. Effect of storage in water and thermocycling on hardness and roughness of resin materials for temporary restorations

    Directory of Open Access Journals (Sweden)

    Jerusa Cleci de Oliveira

    2010-09-01

    Full Text Available PURPOSE: This study evaluated the effect of storage in water and thermocycling on hardness and roughness of resin materials for temporary restorations. MATERIAL AND METHODS: Three acrylic resins (Dencor-De, Duralay-Du, and Vipi Cor-VC were selected and one composite resin (Opallis-Op was used as a parameter for comparison. The materials were prepared according to the manufacturers' instructions and were placed in stainless steel moulds (20 mm in diameter and 5 mm thick. Thirty samples of each resin were made and divided into three groups (n = 10 according to the moment of Vickers hardness (VHN and roughness (Ra analyses: C (control group: immediately after specimen preparation; Sw: after storage in distilled water at 37 °C for 24 hours; Tc: after thermocycling (3000 cycles; 5-55 °C, 30 seconds dwell time. Data were submitted to 2-way ANOVA followed by Tukey's test (α = 0.05. RESULTS: Op resin had higher surface hardness values (p 0.05 in roughness among materials (De = 0.31 ± 0.07; Du = 0.51 ± 0.20; VC = 0.41 ± 0.15; Op = 0.42 ± 0.18. Storage in water did not change hardness and roughness of the tested materials (p > 0.05. There was a significant increase in roughness after thermocycling (p < 0.05, except for material Du, which showed no significant change in roughness in any evaluated period (p = 0.99. CONCLUSION: Thermocycling increased the roughness in most tested materials without affecting hardness, while storage in water had no significant effect in the evaluated properties.

  20. Objective Assessment of Knot-Tying Proficiency With the Fundamentals of Arthroscopic Surgery Training Program Workstation and Knot Tester.

    Science.gov (United States)

    Pedowitz, Robert A; Nicandri, Gregg T; Angelo, Richard L; Ryu, Richard K N; Gallagher, Anthony G

    2015-10-01

    To assess a new method for biomechanical assessment of arthroscopic knots and to establish proficiency benchmarks using the Fundamentals of Arthroscopic Surgery Training (FAST) Program workstation and knot tester. The first study group included 20 faculty at an Arthroscopy Association of North America resident arthroscopy course (19.9 ± 8.25 years in practice). The second group comprised 30 experienced surgeons attending an Arthroscopy Association of North America fall course (17.1 ± 19.3 years in practice). The training group included 44 postgraduate year 4 or 5 orthopaedic residents in a randomized, prospective study of proficiency-based training, with 3 subgroups: group A, standard training (n = 14); group B, workstation practice (n = 14); and group C, proficiency-based progression using the knot tester (n = 16). Each subject tied 5 arthroscopic knots backed up by 3 reversed hitches on alternating posts. Knots were tied under video control around a metal mandrel through a cannula within an opaque dome (FAST workstation). Each suture loop was stressed statically at 15 lb for 15 seconds. A calibrated sizer measured loop expansion. Knot failure was defined as 3 mm of loop expansion or greater. In the faculty group, 24% of knots "failed" under load. Performance was inconsistent: 12 faculty had all knots pass, whereas 2 had all knots fail. In the second group of practicing surgeons, 21% of the knots failed under load. Overall, 56 of 250 knots (22%) tied by experienced surgeons failed. For the postgraduate year 4 or 5 residents, the aggregate knot failure rate was 26% for the 220 knots tied. Group C residents had an 11% knot failure rate (half the overall faculty rate, P = .013). The FAST workstation and knot tester offer a simple and reproducible educational approach for enhancement of arthroscopic knot-tying skills. Our data suggest that there is significant room for improvement in the quality and consistency of these important arthroscopic skills, even for

  1. Stress in hard metal films

    NARCIS (Netherlands)

    Janssen, G.C.A.M.; Kamminga, J.D.

    2004-01-01

    In the absence of thermal stress, tensile stress in hard metal films is caused by grain boundary shrinkage and compressive stress is caused by ion peening. It is shown that the two contributions are additive. Moreover tensile stress generated at the grain boundaries does not relax by ion

  2. Inclusive Hard Diffraction at HERA

    CERN Document Server

    Proskuryakov, Alexander

    2010-01-01

    Recent data from the H1 and ZEUS experiments on hard inclusive diffraction are discussed. Results of QCD analyses of the diffractive deep-inelastic scattering processes are reported. Predictions based on the extracted parton densities are compared to diffractive dijet measurements.

  3. Hard processes in hadronic interactions

    Energy Technology Data Exchange (ETDEWEB)

    Satz, H. [CERN, Geneva (Switzerland)]|[Universitat Bielefeld (Germany); Wang, X.N. [Lawrence Berkeley Lab., CA (United States)

    1995-07-01

    Quantum chromodynamics is today accepted as the fundamental theory of strong interactions, even though most hadronic collisions lead to final states for which quantitative QCD predictions are still lacking. It therefore seems worthwhile to take stock of where we stand today and to what extent the presently available data on hard processes in hadronic collisions can be accounted for in terms of QCD. This is one reason for this work. The second reason - and in fact its original trigger - is the search for the quark-gluon plasma in high energy nuclear collisions. The hard processes to be considered here are the production of prompt photons, Drell-Yan dileptons, open charm, quarkonium states, and hard jets. For each of these, we discuss the present theoretical understanding, compare the resulting predictions to available data, and then show what behaviour it leads to at RHIC and LHC energies. All of these processes have the structure mentioned above: they contain a hard partonic interaction, calculable perturbatively, but also the non-perturbative parton distribution within a hadron. These parton distributions, however, can be studied theoretically in terms of counting rule arguments, and they can be checked independently by measurements of the parton structure functions in deep inelastic lepton-hadron scattering. The present volume is the work of Hard Probe Collaboration, a group of theorists who are interested in the problem and were willing to dedicate a considerable amount of their time and work on it. The necessary preparation, planning and coordination of the project were carried out in two workshops of two weeks` duration each, in February 1994 at CERn in Geneva andin July 1994 at LBL in Berkeley.

  4. Neoplasms of the hard palate.

    Science.gov (United States)

    Aydil, Utku; Kızıl, Yusuf; Bakkal, Faruk Kadri; Köybaşıoğlu, Ahmet; Uslu, Sabri

    2014-03-01

    Although the most common neoplastic lesion of the oral cavity is squamous cell carcinoma (SCC), primary neoplastic lesions of the hard palate have not been systematically reviewed to date. The aim of this study was to determine the histopathologic composition and characteristics of neoplasms of the hard palate. A retrospective analysis of 66 patients with a primary neoplasm of the hard palate managed at the authors' institution from 1985 through 2012 was performed. Demographic features, malignancy rate, histopathologic characteristics and distribution, TNM staging results, metastasis patterns, and management strategies were investigated. The sample was composed of 66 patients (mean age, 45.0 yr; 57.6% men). Neoplasms were benign in 57.6% of cases and malignant in 42.4%. Epithelial neoplasms and mesenchymal neoplasms were encountered in 52 patients (78.8%) and 14 patients (21.2%), respectively. Minor salivary gland tumors (MSGTs) were the most common histopathologic group (60.6%), followed by benign mesenchymal tumors (15.2%), SCCs (12.1%), malignant melanomas (6.1%), lymphomas (3.0%), and sarcomas (3.0%). Although 75.0% of malignant epithelial neoplasms were at an advanced stage, there were no pN+ SCC or malignant MSGT cases at presentation. The most common neoplasms of the hard palate were MSGTs. SCCs were relatively rare in this series. Although three-fourths of neoplasms were at an advanced stage, neck metastasis was not a characteristic of malignant epithelial neoplasms located in the hard palate. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  5. A measurement method of the magnetic properties of magnetic sheet by means of a single sheet tester at audio frequency

    Energy Technology Data Exchange (ETDEWEB)

    Takara, Yusuke; Fujiwara, Koji; Ishihara, Yoshiyuki [Department of Electrical Engineering, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe, Kyoto 610-0321 (Japan); Todaka, Toshiyuki [Department of Electrical Engineering, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe, Kyoto 610-0321 (Japan)], E-mail: yishihar@mail.doshisha.ac.jp

    2008-10-15

    A single sheet tester (SST) for audio frequency of 400 Hz-10 kHz was made experimentally and the magnetizing winding can get the nearly uniform distribution of flux density of a specimen in the longitudinal direction at the frequency up to 10 kHz. The flux densities at various positions of strips measured by the Epstein method were detected by search coils wound on strips at 400 Hz and 1.0 T. They have large discrepancy. However, the magnetic properties obtained from both methods have a little discrepancy. Although the uniformity of flux distribution in the Epstein frame is not sufficient, the average is fairly effective because the magnetic properties can be assumed to be locally linear within the small deviation of flux density.

  6. Nintendo® Wii Fit based sleepiness tester detects impairment of postural steadiness due to 24 h of wakefulness.

    Science.gov (United States)

    Tietäväinen, Aino; Gates, Fred K; Meriläinen, Antti; Mandel, Jeff E; Hæggström, Edward

    2013-12-01

    A field-usable sleepiness tester could reduce sleepiness related accidents. 15 subjects' postural steadiness was measured with a Nintendo(®) Wii Fit balance board every hour for 24 h. Body sway was quantified with complexity index, CI, and the correlation between CI and alertness predicted by a three-process model of sleepiness was calculated. The CI group average was 8.9 ± 1.3 for alert and 7.9 ± 1.4 for sleep deprived subjects (p < 0.001, ρ = 0.94). The Wii Fit board detects the impairment of postural steadiness. This may allow large scale sleepiness testing outside the laboratory setting. Copyright © 2013 IPEM. All rights reserved.

  7. The Effect of Geographical Separation, Mediated Communications, and Culture, on Tester Team Member Trust of Other Information Technology Virtual Project Team Members

    Science.gov (United States)

    Wise, Thomas P.

    2012-01-01

    The purpose of this study was to find evidence that employees in the project role of systems and software tester may experience less effect on their trust of team members in other project roles when working in a virtual team setting. In this study, the independent variables of geographic proximity, culture, and communications were studied as…

  8. Line × Tester Mating Design Analysis for Grain Yield and Yield Related Traits in Bread Wheat (Triticum aestivum L.

    Directory of Open Access Journals (Sweden)

    Zine El Abidine Fellahi

    2013-01-01

    Full Text Available Nine bread wheat (Triticum aestivum L. genotypes were crossed in a line × tester mating design. The 20 F1's and their parents were evaluated in a randomized complete block design with three replications at the Field Crop Institute-Agricultural Experimental Station of Setif (Algeria during the 2011/2012 cropping season. The results indicated that sufficient genetic variability was observed for all characters studied. A899 × Rmada, A899 × Wifak, and A1135 × Wifak hybrids had greater grain yield mean than the parents. A901 line and the tester Wifak were good combiners for the number of grains per spike. MD is a good combiner for 1000-kernel weight and number of fertile tillers. HD1220 is a good general combiner to reduce plant height; Rmada is a good general combiner to shorten the duration of the vegetative growth period. A901 × Wifak is a best specific combiner to reduce plant height, to increase 1000-kernel weight and number of grains per spike. AA × MD is a best specific combiner to reduce duration of the vegetative period, plant height and to increase the number of kernels per spike. A899 × Wifak showed the highest heterosis for grain yield, accompanied with positive heterosis for the number of fertile tillers and spike length, and negative heterosis for 1000-kernel weight and the number of days to heading. σgca2/σsca2,  (σD2/σA21/2 low ratios and low to intermediate estimates of h2ns supported the involvement of both additive and nonadditive gene effects. The preponderance of non-additive type of gene actions clearly indicated that selection of superior plants should be postponed to later generation.

  9. Neck motion kinematics: an inter-tester reliability study using an interactive neck VR assessment in asymptomatic individuals.

    Science.gov (United States)

    Sarig Bahat, Hilla; Sprecher, Elliot; Sela, Itamar; Treleaven, Julia

    2016-07-01

    The use of virtual reality (VR) for assessment and intervention of neck pain has previously been used and shown reliable for cervical range of motion measures. Neck VR enables analysis of task-oriented neck movement by stimulating responsive movements to external stimuli. Therefore, the purpose of this study was to establish inter-tester reliability of neck kinematic measures so that it can be used as a reliable assessment and treatment tool between clinicians. This reliability study included 46 asymptomatic participants, who were assessed using the neck VR system which displayed an interactive VR scenario via a head-mounted device, controlled by neck movements. The objective of the interactive assessment was to hit 16 targets, randomly appearing in four directions, as fast as possible. Each participant was tested twice by two different testers. Good reliability was found of neck motion kinematic measures in flexion, extension, and rotation (0.64-0.93 inter-class correlation). High reliability was shown for peak velocity globally (0.93), in left rotation (0.9), right rotation and extension (0.88), and flexion (0.86). Mean velocity had a good global reliability (0.84), except for left rotation directed movement with moderate reliability (0.68). Minimal detectable change for peak velocity ranged from 41 to 53 °/s, while mean velocity ranged from 20 to 25 °/s. The results suggest high reliability for peak and mean velocity as measured by the interactive Neck VR assessment of neck motion kinematics. VR appears to provide a reliable and more ecologically valid method of cervical motion evaluation than previous conventional methodologies.

  10. Synthesis and characterisation of ultra-hard and lightweight AlMgB14–xTiB2 composites for wear-resistance and ballistic protection

    Directory of Open Access Journals (Sweden)

    Varužan Kevorkijan

    2015-03-01

    Full Text Available As an alternative to mechanical alloying, high temperature synthesis (HTS of ultra-hard, super-abrasive AlMgB14 was performed under normal pressure. The reaction mixture consisted of elemental Al and B, whereas Mg was added in the form of a Mgprecursor which liberates elemental magnesium approximately 400 ºC above the melting point of Mg, in this way reducing its evaporation during heating-up. 95 wt % conversion to AlMgB14 and 5 wt % to MgAl2O4 was achieved. The synthesized AlMgB14 baseline powder, as well as mixtures of AlMgB14 consisting of 30, 50 and 70 wt% of TiB2, were hot pressed to near theoretical density. The various samples produced were characterized for microstructure and hardness. A microhardness of 29.4GPa in hot pressed AlMgB14 and a maximum Vickers hardness of 30.2 GPa in hot pressed samples of AlMgB14 reinforced with 70 wt% of TiB2 particles (d50=4,1µm was achieved. Future project milestones necessary for achieving a higher AlMgB14 reaction yield, reducing the MgAl2O4 content and producing sinter-active AlMgB14 powder, as well as hot pressed composites processing improvement for gaining maximum hardness are also presented.

  11. MC-TESTER: a universal tool for comparisons of Monte Carlo predictions for particle decays in high energy physics

    Science.gov (United States)

    Golonka, P.; Pierzchała, T.; Waş, Z.

    2004-02-01

    Theoretical predictions in high energy physics are routinely provided in the form of Monte Carlo generators. Comparisons of predictions from different programs and/or different initialization set-ups are often necessary. MC-TESTER can be used for such tests of decays of intermediate states (particles or resonances) in a semi-automated way. Our test consists of two steps. Different Monte Carlo programs are run; events with decays of a chosen particle are searched, decay trees are analyzed and appropriate information is stored. Then, at the analysis step, a list of all found decay modes is defined and branching ratios are calculated for both runs. Histograms of all scalar Lorentz-invariant masses constructed from the decay products are plotted and compared for each decay mode found in both runs. For each plot a measure of the difference of the distributions is calculated and its maximal value over all histograms for each decay channel is printed in a summary table. As an example of MC-TESTER application, we include a test with the τ lepton decay Monte Carlo generators, TAUOLA and PYTHIA. The HEPEVT (or LUJETS) common block is used as exclusive source of information on the generated events. Program summaryTitle of the program:MC-TESTER, version 1.1 Catalogue identifier: ADSM Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADSM Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Computer: PC, two Intel Xeon 2.0 GHz processors, 512MB RAM Operating system: Linux Red Hat 6.1, 7.2, and also 8.0 Programming language used:C++, FORTRAN77: gcc 2.96 or 2.95.2 (also 3.2) compiler suite with g++ and g77 Size of the package: 7.3 MB directory including example programs (2 MB compressed distribution archive), without ROOT libraries (additional 43 MB). No. of bytes in distributed program, including test data, etc.: 2 024 425 Distribution format: tar gzip file Additional disk space required: Depends on the analyzed particle: 40 MB in the case

  12. Effect of different hardness nanoparticles on friction properties of magnetorheological fluids

    Science.gov (United States)

    Zhao, Mingmei; Zhang, Jinqiu; Yao, Jun

    2017-10-01

    Magnetorheological fluids (MRFs) exhibit different wear performance when nanoparticles with different hardness are added. In this study, three solid particles with different hardness are considered to study the variation in MRF performance. The friction and wear properties of the MRF are measured by using a four-ball friction and wear tester, and the surface of the steel ball was observed using a three-dimensional white light interferometer. Also, the rheological properties of MRF are tested by using an Anton-Paar rheometer. The results show that the addition of graphite yields a stable friction process and does not degrade the rheological properties of MRF. Nano-diamond increases the shear yield strength and reduces the wall slip to a greater extent. However, the wear is more serious in this case. Copper particles are unstable, and their surface activity is too high to get adsorbed on the surface of iron powder aggravating the settlement rate. The above three MRFs with different kinds of nano-particles present a more regular grinding spot, and the nano-particles have a certain repair function to the surface.

  13. Super hard WC-Cr composite coatings. An approach to potential wear applications

    Energy Technology Data Exchange (ETDEWEB)

    Sancakoglu, Orkut; Celik, Erdal [Dokuz Eylul Univ., Izmir (Turkey). Dept. of Metallurgy and Materials Engineering

    2016-11-01

    In this study, submicron (APS = 200 nm) tungsten carbide (WC) ceramic particles were co-deposited with chromium metal (Cr) via electro-co-deposition system to fabricate WC-Cr metal matrix composite coatings. Instead of traditional electrodeposition cells, a new system was designed and coatings were fabricated using this system. Phase identifications of the coatings were performed by X-ray diffractometry (XRD) and surface morphologies were investigated using energy dispersive X-ray spectroscopy (EDS) with attached scanning electron microscope (SEM). Hardness values of the coatings were performed under 980.7 mN applied load using a microhardness tester. It was concluded that WC ceramic particles were physically adsorbed on the cathode surface and formed a composite structure with metal Cr and co-deposition of submicron sized ceramic particles with metals via electrodeposition system was strictly successful. In addition, with respect to the reference coatings, WC reinforced composite coatings depict an increased hardness up to twice its value. Frequency, as a parameter of pulse current, is determined as an effective parameter in co-deposition.

  14. Evaluating the Effect of Hardness on Erosion Characteristics of Aluminum and Steels

    Science.gov (United States)

    Malik, J.; Toor, I. H.; Ahmed, W. H.; Gasem, Z. M.; Habib, M. A.; Ben-Mansour, R.; Badr, H. M.

    2014-06-01

    In this paper, the erosion behavior of commonly used stainless steels (AISI 310S, AISI 316), carbon steel (AISI 1020), and Aluminum 6060 were experimentally investigated. The effect of hardness on erosion rates and on the morphologies of eroded surfaces has been evaluated. The experiments were carried out using an air jet erosion tester and utilizing angular alumina as erodent with 50 µm particle size. The samples were tested at six different impact angles (15°, 30°, 45°, 60°, 75°, and 90°) using three different impact velocities (30, 60, and 100 m/s). The eroded surfaces were analyzed using a scanning electron microscope (SEM) for the evaluation of material degradation. The erosion rates were found to increase with the increase of the alloy bulk hardness and Aluminum 6060 showed maximum erosion resistance. For all specimens, the erosion rates were found to increase with the increase of impact velocity and the maximum erosion rate was found to occur between 15° and 30° impact angles. The obtained results were found to correlate very well with Oka et al. (Wear, 259:95-101, 2005) erosion model.

  15. Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period

    Directory of Open Access Journals (Sweden)

    Ugur Erdemir

    2013-04-01

    Full Text Available Objectives: This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. Material and Methods: A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group. For the control groups, the specimens were stored in distilled water for 24 hours at 37°C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05. Results: Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (p<0.001 in different solutions (p<0.001. The effect of different solutions on the surface hardness values of the restorative materials was tested using Bonferroni's multiple comparison tests, and it was observed that specimens stored in distilled water demonstrated statistically significant lower mean surface hardness reductions when compared to the specimens immersed in sports and energy drinks after a 1-month evaluation period (p<0.001. The compomer was the most affected by an acidic environment, whereas the composite resin materials were the least affected materials. Conclusions: The effect of sports and energy drinks on the surface hardness of a restorative material depends on the duration of exposure time, and the composition of the material.

  16. Hip- and knee-strength assessments using a hand-held dynamometer with external belt-fixation are inter-tester reliable.

    Science.gov (United States)

    Thorborg, Kristian; Bandholm, Thomas; Hölmich, Per

    2013-03-01

    In football, ice-hockey, and track and field, injuries have been predicted, and hip- and knee-strength deficits quantified using hand-held dynamometry (HHD). However, systematic bias exists when testers of different sex and strength perform the measurements. Belt-fixation of the dynamometer may resolve this. The aim of the present study was therefore to examine the inter-tester reliability concerning strength assessments of isometric hip abduction, adduction, flexion, extension and knee-flexion strength, using HHD with external belt-fixation. Twenty-one healthy athletes (6 women), 30 (8.6) (mean (SD)) years of age, were included. Two physiotherapy students (1 female and 1 male) performed all the measurements after careful instruction and procedure training. Isometric hip abduction, adduction, flexion, extension, and knee-flexion strength were tested. The tester-order and hip-action order were randomised. No systematic between-tester differences (bias) were observed for any of the hip or knee actions. The intra-class correlation coefficients (ICC 2.1) ranged from 0.76 to 0.95. Furthermore, standard errors of measurement in per cent (SEM %) ranged from 5 to 11 %, and minimal detectable change in per cent (MDC %) from 14 to 29 % for the different hip and knee actions. The present study shows that isometric hip- and knee-strength measurements have acceptable inter-tester reliability at the group level, when testing strong individuals, using HHD with belt-fixation. This procedure is therefore perfectly suited for the evaluation and monitoring of strong athletes with hip, groin and hamstring injuries, some of the most common and troublesome injuries in sports. Diagnostic, Level III.

  17. CMS results on hard diffraction

    CERN Document Server

    INSPIRE-00107098

    2013-01-01

    In these proceedings we present CMS results on hard diffraction. Diffractive dijet production in pp collisions at $\\sqrt{s}$=7 TeV is discussed. The cross section for dijet production is presented as a function of $\\tilde{\\xi}$, representing the fractional momentum loss of the scattered proton in single-diffractive events. The observation of W and Z boson production in events with a large pseudo-rapidity gap is also presented.

  18. Playing Moderately Hard to Get

    Directory of Open Access Journals (Sweden)

    Stephen Reysen

    2013-12-01

    Full Text Available In two studies, we examined the effect of different degrees of attraction reciprocation on ratings of attraction toward a potential romantic partner. Undergraduate college student participants imagined a potential romantic partner who reciprocated a low (reciprocating attraction one day a week, moderate (reciprocating attraction three days a week, high (reciprocating attraction five days a week, or unspecified degree of attraction (no mention of reciprocation. Participants then rated their degree of attraction toward the potential partner. The results of Study 1 provided only partial support for Brehm’s emotion intensity theory. However, after revising the high reciprocation condition vignette in Study 2, supporting Brehm’s emotion intensity theory, results show that a potential partners’ display of reciprocation of attraction acted as a deterrent to participants’ intensity of experienced attraction to the potential partner. The results support the notion that playing moderately hard to get elicits more intense feelings of attraction from potential suitors than playing too easy or too hard to get. Discussion of previous research examining playing hard to get is also re-examined through an emotion intensity theory theoretical lens.

  19. Effect of Ball Milling Time on Microstructure and Hardness of Porous Magnesium/Carbon Nanofiber Composites

    Science.gov (United States)

    Xu, Huiru; Zou, Ning; Li, Qizhen

    2017-07-01

    Porous magnesium/carbon nanofiber composites were produced using a powder metallurgic method to study the effect of ball milling time on their microstructure and hardness. Three ball milling times (240 min, 320 min, and 480 min) and two carbon nanofiber concentrations (0.05% and 1%) were utilized in the production of these porous composites. The increase of ball milling time led to the gradual decrease of the average size of magnesium powders from the initial 40 µm to about 26 µm after 480 min of ball milling. The powder size range first increased with the increase of ball milling time from 240 min to 320 min, and then decreased with the further increase of ball milling time to 480 min. Among the three ball milling times, the produced porous composites from the powders after 320 min of ball milling have the largest average pore size. With the increase of ball milling time from 240 min to 320 min and then to 480 min, the average Vickers microhardness data first decreased and then increased for Mg-1%C porous composites along the cross-sections parallel to the compact processing direction, increased for the cross-sections perpendicular to the compact processing direction for Mg-1%C porous composites, first increased and then decreased for the cross-sections parallel to the compact processing direction for Mg-0.05%C porous composites, and slightly decreased for the cross-sections perpendicular to the compact processing direction for Mg-0.05%C porous composites.

  20. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... Quitting drugs is hard because addiction is a brain disease. Your brain is like a control tower that sends out ... and choices. Addiction changes the signals in your brain and makes it hard to feel OK without ...

  1. Hardness of Potable Water in Southwestern Skane

    OpenAIRE

    Kos, Z.

    1982-01-01

    This paper is concerned with water hardness in the municipal water supply systems. After a general overview of the health aspects of water hardness, this issue is discussed in the specific context of Southwestern Skane, Sweden.

  2. The effect of Coca-Cola and fruit juices on the surface hardness of glass-ionomers and 'compomers'.

    Science.gov (United States)

    Aliping-McKenzie, M; Linden, R W A; Nicholson, J W

    2004-11-01

    The interaction of tooth-coloured dental restorative materials (a conventional glass-ionomer, two resin-modified glass-ionomers and two compomers) with acidic beverages has been studied with the aim of investigating how long-term contact affects solution pH and specimen surface hardness. For each material (ChemFil Superior, ChemFlex, Vitremer Core Build-Up/Restorative, Fuji II LC, Dyract AP and F2000) disc-shaped specimens were prepared and stored in sets of six in the following storage media: 0.9% NaCl (control), Coca-Cola, apple juice and orange juice. After time intervals of 1 day, 1 week, 1 month, 3 months, 4 months, 6 months and 1 year, solution pH and Vickers Hardness Number were determined for each individual specimen. Differences were analysed by anova followed by Student-Newman-Keuls post hoc analysis. All materials were found to reduce the pH of the 0.9% NaCl, but to increase the pH of the acidic beverages. The conventional glass-ionomers dissolved completely in apple juice and orange juice, but survived in Coca-Cola, albeit with a significantly reduced hardness after 1 year. The other materials survived in apple juice and orange juice, but showed greater reductions in surface hardness in these beverages than in Coca-Cola. Fruit juices were thus shown to pose a greater erosive threat to tooth coloured materials than Coca-Cola, a finding which is similar to those concerning dentine and enamel towards these drinks.

  3. Structural stability and hardness of carburized surfaces of 316 stainless steel after welding and after neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Farrell, K. [Metals and Ceramics Division, Oak Ridge National Laboratory, P.O. Box 2008, MS-6151, Oak Ridge, TN 37831 (United States)]. E-mail: p-k-f@comcast.net; Byun, T.S. [Metals and Ceramics Division, Oak Ridge National Laboratory, P.O. Box 2008, MS-6151, Oak Ridge, TN 37831 (United States)

    2006-09-15

    Surface hardening treatments offer promise of mitigating the threat of liquid cavitation pitting erosion at the interior surfaces of the austenitic 316 stainless steel vessel that will hold the liquid mercury target of the Spallation Neutron Source. One treatment is a commercial carburization process in which carbon is impregnated at low temperature at concentrations up to 6 wt% in supersaturated solid solution to depths of about 33 {mu}m. The surface hardness of 316L steel is raised from 150 to 200HV{sub 0.05} (micro-Vickers hardness number at a 50 g load) to 1000-1200HV{sub 0.05}. It is shown that during subsequent electron beam welding the supersaturated carburized layer in the heat affected zone decomposes to a tiered microstructure of carbide phases in austenite. The hardness of this complex decomposition microstructure is in the range 530-1200HV{sub 0.05}, depending on the exposure temperature, the local carbon level, and the size of the carbide particles. To test whether the carburized solid solution layer would break down under atomic displacements from proton and neutron irradiation in service, specimens of annealed and 20% cold-rolled 316LN steel were neutron irradiated to 1 dpa at 60-100 deg. C. No softening of the layer was detected. Rather, the hardness of the layers was increased by 2-12%, compared to increases of 81% and 43% for the annealed and 20% cold rolled substrate materials, respectively. Optical microscopy examinations of the surfaces of the as-carburized-and-irradiated specimens revealed no sign of decomposition attributable to irradiation.

  4. Influences of multiple firings and aging on surface roughness, strength and hardness of veneering ceramics for zirconia frameworks.

    Science.gov (United States)

    Tang, Xuehua; Luo, Huinan; Bai, Yang; Tang, Hui; Nakamura, Takashi; Yatani, Hirofumi

    2015-09-01

    To evaluate the effects of multiple firings and aging on surface roughness, strength, and hardness of veneering ceramics for zirconia frameworks. Five different veneering ceramics for zirconia frameworks were used: Vintage ZR (ZR), Cerabien ZR (CZR), VitaVM9 (VM9), Cercon ceram KISS (KISS), and IPS e.max ceram (e.max). Specimens were fired 2 or 10 times in order to accelerate aging. Surface roughness was evaluated using laser profilometry. Flexural strength and Vickers hardness were also measured. Surface topography was observed using scanning electron microscopy. After accelerated aging, the surface roughness of all specimens fired 10 times was significantly lower than that of the same specimens fired 2 times (P=0.000). Except for VM9, the flexural strength of all specimens fired 10 times was greater than that of the same specimens fired 2 times, and the differences were significant for ZR and CZR (Phardness of ZR and VM9 fired 10 times was significantly higher than that of the same specimens fired 2 times (Phardness of many aged veneering ceramics used for zirconia restorations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Hardness Optimization for Al6061-MWCNT Nanocomposite Prepared by Mechanical Alloying Using Artificial Neural Networks and Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Mehrdad Mahdavi Jafari

    2017-06-01

    Full Text Available Among artificial intelligence approaches, artificial neural networks (ANNs and genetic algorithm (GA are widely applied for modification of materials property in engineering science in large scale modeling. In this work artificial neural network (ANN and genetic algorithm (GA were applied to find the optimal conditions for achieving the maximum hardness of Al6061 reinforced by multiwall carbon nanotubes (MWCNTs through modeling of nanocomposite characteristics. After examination the different ANN architectures an optimal structure of the model, i.e. 6-18-1, is obtained with 1.52% mean absolute error and R2 = 0.987. The proposed structure was used as fitting function for genetic algorithm. The results of GA simulation predicted that the combination sintering temperature 346 °C, sintering time 0.33 h, compact pressure 284.82 MPa, milling time 19.66 h and vial speed 310.5 rpm give the optimum hardness, (i.e., 87.5 micro Vickers in the composite with 0.53 wt% CNT. Also, sensitivity analysis shows that the sintering time, milling time, compact pressure, vial speed and amount of MWCNT are the significant parameter and sintering time is the most important parameter. Comparison of the predicted values with the experimental data revealed that the GA–ANN model is a powerful method to find the optimal conditions for preparing of Al6061-MWCNT.

  6. Contact Allergy To Hard Contact Lens

    Directory of Open Access Journals (Sweden)

    J S Pasricha

    1985-01-01

    Full Text Available Three patients developed recurrent irritation, redness and watery discharge from their eyes after using hard contact lens. Patch tests were positive with the material of the hard contact lens and negative with teepol, sodium lauryl sulphate and material of the soft contact lens. All the three patients became alright after they stopped,using hard contact lens.

  7. 7 CFR 201.30 - Hard seed.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Hard seed. 201.30 Section 201.30 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Vegetable Seeds § 201.30 Hard seed. The label shall show the percentage of hard seed, if...

  8. 7 CFR 201.21 - Hard seed.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Hard seed. 201.21 Section 201.21 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.21 Hard seed. The label shall show the percentage of hard seed...

  9. Systematic hardness studies on lithium niobate crystals

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 23; Issue 2. Systematic hardness studies on lithium niobate crystals ... In view of discrepancies in the available information on the hardness of lithium niobate, a systematic study of the hardness has been carried out. Measurements have been made on two pure lithium ...

  10. 7 CFR 201.57 - Hard seeds.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Hard seeds. 201.57 Section 201.57 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Germination Tests in the Administration of the Act § 201.57 Hard seeds. Seeds which remain hard at...

  11. Microstructure and mechanical properties of a microalloyed steel after thermal treatments

    Directory of Open Access Journals (Sweden)

    André Barros Cota

    2003-06-01

    Full Text Available The properties of a microalloyed steel, with Nb and V in its composition, were studied, after different intercritical thermal treatments and at different austenitizing and tempering temperatures. The mechanical properties of the specimens were measured in a Vickers hardness tester, and their microstructures were analyzed by optical microscopy, with the aid of a digital image processor. After austenitizing at 1100 °C and tempering at 625 °C, the samples showed significantly higher tempering resistance, reflected by their retention of high hardness, which may be associated with a secondary hardening precipitation of Nb carbon nitrides. In the sample with dual-phase microstructure, the martensite volume fraction varied from 18.2 to 26.3% and the ferrite grain size remained unchanged, upon the variation of the time length of the intercritical treatments. Tempered samples showed Vickers hardness (HVN varying from 327 to 399, and dual-phase samples showed HVN from 362 to 429.

  12. Radiation Hardness Assurance (RHA) Guideline

    Science.gov (United States)

    Campola, Michael J.

    2016-01-01

    Radiation Hardness Assurance (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 mission space environment. The subset of interests for NEPP and the REAG, are EEE parts. It is important to register that all of these undertakings are in a feedback loop and require constant iteration and updating throughout the mission life. More detail can be found in the reference materials on applicable test data for usage on parts.

  13. Carbon Equivalent and Maximum Hardness

    OpenAIRE

    Haruyoshi, Suzuki; Head Office, Nippon Steel Corporation

    1984-01-01

    The accuracy of formulae for estimating the maximum hardness values of the HAZ from chemical composition and cooling time for welds in high strength steel is discussed and a new formula. NSC-S, is proposed which uses only C%, Pcm% and cooling time for the purpose of satisfactory accuracy. IIW CE and Ito-Bessyo Pcm carbon equivalent alone are not satisfactory in establishing Hmax values. The former is good only for slow cooling, t8/5 longer than 10 seconds, while the latter is good only for fa...

  14. Hard Identity and Soft Identity

    Directory of Open Access Journals (Sweden)

    Hassan Rachik

    2006-04-01

    Full Text Available Often collective identities are classified depending on their contents and rarely depending on their forms. Differentiation between soft identity and hard identity is applied to diverse collective identities: religious, political, national, tribal ones, etc. This classification is made following the principal dimensions of collective identities: type of classification (univocal and exclusive or relative and contextual, the absence or presence of conflictsof loyalty, selective or totalitarian, objective or subjective conception, among others. The different characteristics analysed contribute to outlining an increasingly frequent type of identity: the authoritarian identity.

  15. Hip- and knee-strength assessments using a hand-held dynamometer with external belt-fixation are inter-tester reliable

    DEFF Research Database (Denmark)

    Thorborg, Kristian; Bandholm, Thomas; Hölmich, Per

    2013-01-01

    PURPOSE: In football, ice-hockey, and track and field, injuries have been predicted, and hip- and knee-strength deficits quantified using hand-held dynamometry (HHD). However, systematic bias exists when testers of different sex and strength perform the measurements. Belt-fixation of the dynamome......PURPOSE: In football, ice-hockey, and track and field, injuries have been predicted, and hip- and knee-strength deficits quantified using hand-held dynamometry (HHD). However, systematic bias exists when testers of different sex and strength perform the measurements. Belt......-fixation. This procedure is therefore perfectly suited for the evaluation and monitoring of strong athletes with hip, groin and hamstring injuries, some of the most common and troublesome injuries in sports. LEVELS OF EVIDENCE: Diagnostic, Level III....

  16. Parallel processing multitemperature robotic tester and burn-in oven for InGaAsP lasers

    Science.gov (United States)

    Gazier, Michael A.; Leung, Ming; Cremer, Ed; Hess, Dave; Volkmer, Frank

    1994-06-01

    Coolerless lasers meeting Bellcore technical advisory TA-TSY-000983 are needed for access applications. To this end, a parallel processing multi-temperature robotic tester (MTRT) for high volume dc characterization of semiconductor lasers over the temperature range -40 degree(s)C to +85 degree(s)C is presented. The cartridge based system is fully integrated with the device burn-in oven, allowing for automated testing and handling. The robot picks devices from a cartridge and places them in one of seven test pods, each independently temperature controlled and serviced by a stage with a photodetector, movable polarizer, and a fiber. The test pods measure dc, pulsed, polarized and non-polarized L/Is, V/Is, and optical spectrums of the devices at each temperature. The test software is multi- threaded and includes a custom task scheduler and mailbox system. This C software is three- tiered with a user-interface process, a test system process, and a database link process. All test specifications, device specifications, and device data are acquired from and stored back onto a remote database for data analysis and reporting. The database is also accessed via a 4GL user- friendly interface. An independent cartridge-based burn-in performs the automatic current control (ACC) burn-in cycles between tests and integrates into the robotic test system equipment. Together, the robot and the burn-in oven perform all process steps required between the post-bond and final test manufacturing stages.

  17. Glitch game testers: The design and study of a learning environment for computational production with young African American males

    Science.gov (United States)

    DiSalvo, Elizabeth Betsy

    The implementation of a learning environment for young African American males, called the Glitch Game Testers, was launched in 2009. The development of this program was based on formative work that looked at the contrasting use of digital games between young African American males and individuals who chose to become computer science majors. Through analysis of cultural values and digital game play practices, the program was designed to intertwine authentic game development practices and computer science learning. The resulting program employed 25 African American male high school students to test pre-release digital games full-time in the summer and part-time in the school year, with an hour of each day dedicated to learning introductory computer science. Outcomes for persisting in computer science education are remarkable; of the 16 participants who had graduated from high school as of 2012, 12 have gone on to school in computing-related majors. These outcomes, and the participants' enthusiasm for engaging in computing, are in sharp contrast to the crisis in African American male education and learning motivation. The research presented in this dissertation discusses the formative research that shaped the design of Glitch, the evaluation of the implementation of Glitch, and a theoretical investigation of the way in which participants navigated conflicting motivations in learning environments.

  18. Evolution of the microstructure of unmodified and polymer modified asphalt binders with aging in an accelerated weathering tester.

    Science.gov (United States)

    Menapace, Ilaria; Masad, Eyad

    2016-09-01

    This paper presents findings on the evolution of the surface microstructure of two asphalt binders, one unmodified and one polymer modified, directly exposed to aging agents with increasing durations. The aging is performed using an accelerated weathering tester, where ultraviolet radiation, oxygen and an increased temperature are applied to the asphalt binder surface. Ultraviolet and dark cycles, which simulated the succession of day and night, alternated during the aging process, and also the temperature varied, which corresponded to typical summer day and night temperatures registered in the state of Qatar. Direct aging of an exposed binder surface is more effective in showing microstructural modifications than previously applied protocols, which involved the heat treatment of binders previously aged with standardized methods. With the new protocol, any molecular rearrangements in the binder surface after aging induced by the heat treatment is prevented. Optical photos show the rippling and degradation of the binder surface due to aging. Microstructure images obtained by means of atomic force microscopy show gradual alteration of the surface due to aging. The original relatively flat microstructure was substituted with a profoundly different microstructure, which significantly protrudes from the surface, and is characterized by various shapes, such as rods, round structures and finally 'flower' or 'leaf' structures. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

  19. Design and analysis of a toroidal tester for the measurement of core losses under axial compressive stress

    Science.gov (United States)

    Alatawneh, Natheer; Rahman, Tanvir; Lowther, David A.; Chromik, Richard

    2017-06-01

    Electric machine cores are subjected to mechanical stresses due to manufacturing processes. These stresses include radial, circumferential and axial components that may have significant influences on the magnetic properties of the electrical steel and hence, on the output and efficiencies of electrical machines. Previously, most studies of iron losses due to mechanical stress have considered only radial and circumferential components. In this work, an improved toroidal tester has been designed and developed to measure the core losses and the magnetic properties of electrical steel under a compressive axial stress. The shape of the toroidal ring has been verified using 3D stress analysis. Also, 3D electromagnetic simulations show a uniform flux density distribution in the specimen with a variation of 0.03 T and a maximum average induction level of 1.5 T. The developed design has been prototyped, and measurements were carried out using a steel sample of grade 35WW300. Measurements show that applying small mechanical stresses normal to the sample thickness rises the delivered core losses, then the losses decrease continuously as the stress increases. However, the drop in core losses at high stresses does not go lower than the free-stress condition. Physical explanations for the observed trend of core losses as a function of stress are provided based on core loss separation to the hysteresis and eddy current loss components. The experimental results show that the effect of axial compressive stress on magnetic properties of electrical steel at high level of inductions becomes less pronounced.

  20. Comparative study on the lateral run-out of friction surfaces measurement of brake discs using a brake roller tester and a dial gauge

    OpenAIRE

    Toma Marius; Andreescu Cristian; Micu Dan

    2017-01-01

    Brake system diagnosis is one of the most common and necessary technical operations applied to the car, regardless of its type and operating phases. Measuring the diagnostic parameters on a roller brake tester is a fast operation with no disassembly necessary. Measuring the run-out of friction surfaces of brake discs with a dial gauge is an action that requires more extensive preparatory operations but it offers a high accuracy of the results. The paper aims to analyze the correlation between...

  1. Annealing for plant life management: hardness, tensile and Charpy toughness properties of irradiated, annealed and re-irradiated mock-up low alloy nuclear pressure vessel steel

    Energy Technology Data Exchange (ETDEWEB)

    Tipping, Philip; Cripps, Robin (Paul Scherrer Inst. (PSI), Villigen (Switzerland))

    1994-01-01

    Hardness, tensile and Charpy properties of an irradiated (I) and irradiated-annealed-reirradiated (IAR) mock-up pressure vessel steel are presented. Spectrum tailored pressurized light water reactor (PWR) irradiation at 290[sup o]C by fast neutrons up to nominal fluences of 5 x 10[sup 19]/cm[sup 2] (E [>=] 1 MeV) in a swimming pool type reactor caused the hardness, tensile yield stress and tensile strength to increase. Embrittlement also occurred as indicated by Charpy toughness tests. The optimum annealing heat treatment for the main program was determined using isochronal and isothermal runs on the material and measuring the Vickers microhardness. The response to an intermediate annealing treatment (460[sup o]C for 18 h), when 50% of the target fluence has been reached and then irradiating to the required end fluence (IAR condition) was then monitored further by Charpy and tensile mechanical properties. Annealing was beneficial in mitigating overall hardening or embrittlement effects. The rate of re-embrittlement after annealing and re-irradiating was no faster than when no annealing had been performed. Annealing temperatures below 440[sup o]C were indicated as requiring relatively long times, i.e. [>=] 168 h to achieve some reduction in radiation induced hardness for example. (Author).

  2. Performance of testers with different genetic structure for evaluation of maize inbred lines Desempenho de testadores com diferentes estruturas genéticas para avaliação de linhagens endogâmicas de milho

    Directory of Open Access Journals (Sweden)

    Lauro José Moreira Guimarães

    2012-05-01

    Full Text Available The objective of this study was to evaluate four maize testers for identification of superior inbreed lines in testcross. The four testers evaluated are cultivars with narrow or wide genetic base (single-cross hybrids and open pollinated varieties and two kernel types (flint or dent. SynD and SynF testers are open pollinated varieties with dent and flint kernels, respectively, and FSH and DSH testers are single-cross hybrids with flint and dent kernels, respectively. SynD tester showed the biggest genetic variance among the maize inbreed lines in crosses. The effects of general combining ability (GCA for lines and specific combining ability (SCA for lines x testers were significant, whereas GCA effects for testers were not significant. SynD and SynF testers identified the largest number of lines with higher GCA. The DSH and FSH testers showed suitable to identify lines with high SCA. It was concluded that SynD and SynF testers are adequate to identify inbreed lines with high GCA effects, and it's possible to identify new lines with high heterotic potential in each one of the four testers.O objetivo deste estudo foi avaliar quatro testadores de milho quanto à capacidade de identificar linhagens superiores em testcross. Os quatro testadores avaliados são cultivares com base genética ampla (variedades de polinização aberta e estreita (híbridos simples e dois tipos de grãos (duro e dentado. Os testadores SynD e SynF são populações de milho de polinização aberta com grãos dentados e duros, respectivamente, e FSH e DSH são híbridos simples com grãos duros e dentados, respectivamente. O testador SynD possibilitou a maior expressão de variância genética entre os cruzamentos com as linhagens. A capacidade geral de combinação (CGC das linhagens e a capacidade específica de combinação (CEC entre linhagens e testadores foram significativas, enquanto que os efeitos de CGC dos testadores foram não significativos. Concluiu-se que os

  3. Elastic modulus of hard tissues.

    Science.gov (United States)

    Bar-On, Benny; Wagner, H Daniel

    2012-02-23

    This work aims at evaluating the elastic modulus of hard biological tissues by considering their staggered platelet micro-structure. An analytical expression for the effective modulus along the stagger direction is formulated using three non-dimensional structural variables. Structures with a single staggered hierarchy (e.g. collagen fibril) are first studied and predictions are compared with the experimental results and finite element simulations from the literature. A more complicated configuration, such as an array of fibrils, is analyzed next. Finally, a mechanical model is proposed for tooth dentin, in which variations in the multi-scale structural hierarchy are shown to significantly affect the macroscopic mechanical properties. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Infinite hard-sphere system

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, R.K.

    1975-09-01

    The time-evolution for the system of infinitely many particles in space interacting by a hard-sphere potential is constructed. Examples abound of configurations of the infinite system having more than one solution to the Newtonian equations of motion. A regularity condition is imposed on the solutions sought, which limits the growth of velocities and of the length of chains of particles close together as absolute value x ..-->.. infinity; it is proven that through any point of the phase space there passes at most one regular solution. Every point in a subset X bar of the phase space X is the initial point of a regular solution which is defined for all time. The subset X bar is of full measure for every Gibbs state and is invariant under the one-parameter group T/sup t/ of shifts along solution trajectories. Moreover, the flow T/sup t/ leaves every Gibbs state invariant. The solutions constructed are limits, as R ..-->.. infinity, of motions in which particles inside the sphere of radius R are elastically reflected from its boundary while those outside remain fixed. For this reason, one also studies the motion of finite systems. For finitely many hard-sphere particles in a region of space with piecewise smooth boundary, the set of points of the phase space through which solutions exist for all time without triple or grazing collisions, are of full Lebesgue measure and are residual in the sense of Baire. Liouville's Theorem holds for the one-parameter group of shift-transformations T/sup t/. Finally, we give examples in which a single billiard moving in the plane is reflected infinitely often from a boundary curve in finite time, and necessary conditions for such singularities to occur are established.

  5. INFLUENCE OF ELECTRIC SPARK ON HARDNESS OF CARBON STEEL

    Directory of Open Access Journals (Sweden)

    I. O. Vakulenko

    2014-03-01

    Full Text Available Purpose. The purpose of work is an estimation of influence of an electric spark treatment on the state of mouldable superficial coverage of carbon steel. Methodology. The steel of fragment of railway wheel rim served as material for research with chemical composition 0.65% С, 0.67% Mn, 0.3% Si, 0.027% P, 0.028% S. Structural researches were conducted with the use of light microscopy and methods of quantitative metallography. The structural state of the probed steel corresponded to the state after hot plastic deformation. The analysis of hardness distribution in the micro volumes of cathode metal was carried out with the use of microhardness tester of type of PMT-3. An electric spark treatment of carbon steel surface was executed with the use of equipment type of EFI-25M. Findings. After electric spark treatment of specimen surface from carbon steel the forming of multi-layered coverage was observed. The analysis of microstructure found out the existence of high-quality distinctions in the internal structure of coverage metal, depending on the probed area. The results obtained in the process are confirmed by the well-known theses, that forming of superficial coverage according to technology of electric spark is determined by the terms of transfer and crystallization of metal. The gradient of structures on the coverage thickness largely depends on development of structural transformation processes similar to the thermal character influence. Originality. As a result of electric spark treatment on the condition of identical metal of anode and cathode, the first formed layer of coverage corresponds to the monophase state according to external signs. In the volume of coverage metal, the appearance of carbide phase particles is accompanied by the decrease of microhardness values. Practical value. Forming of multi-layered superficial coverage during electric spark treatment is accompanied by the origin of structure gradient on a thickness. The effect

  6. Flexural strength and hardness of resins for interim fixed partial dentures

    Directory of Open Access Journals (Sweden)

    Liju Jacob Jo

    2011-01-01

    Full Text Available Context: Materials used for the fabrication of interim restorations must satisfy biological, esthetic, and functional needs. Strength and wear resistance are two important physical properties contributing to clinical efficiency. Aim: The objective of this in vitro study was to evaluate and compare the flexural strength and hardness of five resins used for the fabrication of interim fixed partial dentures. Materials and Methods: Five groups containing ten specimens of each material were fabricated in customized brass split molds with dimensions 65×10×2.5 mm. The materials subjected to this study were Revotek LC™ (group RLC, Protemp II™ (group PSC, Acry-lux V™ with regular monomer (group AHC, Acry-lux V™ with self-cure monomer (group ASC, DPI™ self-cure tooth molding powder (group DSC. The specimens were polymerized according to the manufacturers′ instructions and were evaluated for flexural strength using a universal testing machine and for hardness using a microhardness tester. Statistical Analysis: The mean of the five groups was compared using one way analysis of variance (ANOVA and pair-wise comparison was done using Tukeys honesty significance difference (HSD test. P≤.05 was considered to be statistically significant. Results: Flexural test results showed that group AHC (79.8950 MPa had the highest flexural strength followed, in descending order, by group PSC (77.9700 MPa, group ASC (63.7150 MPa, group RLC (58.8110 MPa, and group DSC (51.9840 MPa. Statistically, the difference was found to be highly significant among all the groups. The hardness tests showed that group AHC (17.6900 KHN had the highest hardness value followed, in descending order, by group PSC (15.9400 KHN, group RLC (12.6000 KHN, group ASC (11.2500 KHN, and group DSC (8.7700 KHN. Statistically, the difference was found to be highly significant among all the groups. Conclusion: Group AHC, representing a heat-polymerizing resin, showed the highest flexural

  7. A new approach to local hardness

    CERN Document Server

    Gal, T; De Proft, F; Torrent-Sucarrat, M

    2011-01-01

    The applicability of the local hardness as defined by the derivative of the chemical potential with respect to the electron density is undermined by an essential ambiguity arising from this definition. Further, the local quantity defined in this way does not integrate to the (global) hardness - in contrast with the local softness, which integrates to the softness. It has also been shown recently that with the conventional formulae, the largest values of local hardness do not necessarily correspond to the hardest regions of a molecule. Here, in an attempt to fix these drawbacks, we propose a new approach to define and evaluate the local hardness. We define a local chemical potential, utilizing the fact that the chemical potential emerges as the additive constant term in the number-conserving functional derivative of the energy density functional. Then, differentiation of this local chemical potential with respect to the number of electrons leads to a local hardness that integrates to the hardness, and possesse...

  8. Advances in hard nucleus cataract surgery

    Directory of Open Access Journals (Sweden)

    Wei Cui

    2013-11-01

    Full Text Available Security and perfect vision and fewer complications are our goals in cataract surgery, and hard-nucleus cataract surgery is always a difficulty one. Many new studies indicate that micro-incision phacoemulsification in treating hard nucleus cataract is obviously effective. This article reviews the evolution process of hard nuclear cataract surgery, the new progress in the research of artificial intraocular lens for microincision, and analyse advantages and disadvantages of various surgical methods.

  9. Comparative efficiency of plasma and halogen light sources on composite micro-hardness in different curing conditions.

    Science.gov (United States)

    Dietschi, D; Marret, N; Krejci, I

    2003-09-01

    Recent developments have led to the introduction of high power curing lights, which are claimed to greatly reduce the total curing time. This study evaluated the effectiveness of a plasma-curing device (Apollo 95 E) and a halogen device (Heliolux DLX), in different curing conditions. Vicker's micro-hardness values were performed on 1 and 2 mm thick composite discs cured in a natural tooth mold by direct irradiation or indirect irradiation through composite material (2 or 4 mm) and dental tissues (1 mm enamel or 2 mm enamel-dentin). Measures were, respectively, performed after a 1, 3, 6 s (SC, step curing mode) or 18 s (3xSC) exposure to the plasma light, and a 5, 10, 20 or 40 s exposure to the halogen light. With the PAC light used, a 3 s irradiation in the direct curing condition was necessary to reach hardness values similar to those obtained after a 40 s exposure to the halogen light. Using the indirect curing condition, hardness values reached after an 18 s exposure (3xSC mode) with the plasma light were either equivalent or inferior to those obtained with 40 s halogen irradiation. Direct polymerization with the plasma light used requires longer exposure times than those initially proposed by the manufacturer. The effectiveness of plasma generated light was lowered by composite or natural tissues, and therefore requires an important increase in the irradiation time when applied to indirect polymerization. The practical advantage of this polymerization method is less than expected, when compared to traditional halogen curing.

  10. Effects of alpha radiation on hardness and toughness of the borosilicate glass applied to radioactive wastes immobilization; Efectos de la radiacion alfa en la dureza y tenacidad de un vidrio borosilicato utilizado para inmovilizacion de residuos nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Prado, Miguel Oscar; Bernasconi, Norma B. Messi de; Bevilacqua, Arturo Miguel; Arribere, Maria Angelica; Heredia, Arturo D.; Sanfilippo, Miguel [Comision Nacional de Energia Atomica, San Carlos de Bariloche (Argentina). Centro Atomico Bariloche

    1999-11-01

    Borosilicate german glass SG7 samples, obtained by frit sintering, were irradiated with different fluences of thermal neutrons in the nucleus of a nuclear reactor. The nuclear reaction {sup 10} B(n,{alpha}){sup 7} Li, where the {sup 10} B isotope is one of the natural glass components, was used to generate alpha particles throughout the glass volume. The maximum alpha disintegration per unit volume achieved was equivalent to that accumulated in a borosilicate glass with nuclear wastes after 3.8 million years. Through Vickers indentations values for microhardness, stress for 50% fracture probability (Weibull statistics) and estimation of the toughness were obtained as a function of alpha radiation dose. Two counterbalanced effects were found: that due to the disorder created by the alpha particles in the glass and that due to the annealing during irradiation (temperature below 240 deg C). Considering the alpha radiation effect, glasses tend decrease Vickers hardness, and to increase thr 50% fracture probability stress with the dose increase. (author) 11 refs., 6 figs., 2 tabs.

  11. Kekerasan mikro enamel gigi permanen muda setelah aplikasi bahan pemutih gigi dan pasta remineralisasi (Enamel micro hardness of young permanent tooth after bleaching and remineralization paste application

    Directory of Open Access Journals (Sweden)

    Budianto Liwang

    2014-12-01

    Full Text Available Background: Studies showed that bleaching agent had demineralization effect to enamel, and encourage use of remineralization paste after bleaching treatment especially in young permanent tooth which in post-eruptive enamel maturation. Purpose: The study ere aimed to determine the bleaching agent effect on enamel surface micro hardness, and to determine the effect of remineralization paste application on enamel surface micro hardness of young permanent tooth after bleaching treatment. Methods: Fourteen young permanent teeth were placed in a block of resin with a window on the buccal surface enamel. The initial enamel surface hardness was measured using Microvickers Hardness Tester. Then the application of hydrogen peroxide bleaching materials 30% was done three times for 15 minutes and followed by surface hardness of enamel measurement. Samples were divided into 2 groups; the first group was applied paste of Hydroxy apatite + NaF 1450ppm , and the second group was applied paste of CPP–ACP + NaF 900ppm. Each paste was applied for 30 minutes for 7 days, then the enamel surface hardness of samples were measured. Results: The enamel surface micro hardness decreased after bleaching from 333.09 ± 10.49 VHN to 299.15±5.70 VHN. Micro hardness after application of Hidroxy apatite + NaF 1450ppm was 316.61±5.87 VHN and after application of CPP-ACP + NaF 900ppm was 319.94±3.25 VHN, however the micro hardness still lower than initial micro hardness. Conclusion: Tooth bleaching agent caused a decrease of enamel surface micro hardness in young permanent tooth. The use of remineralization paste enabled to increase the enamel surface micro hardness young permanent tooth.Latar belakang: Penelitian-penelitian sebelumnya menunjukkan bahwa produk pemutih gigi memiliki efek demineralisasi enamel gigi, dan mendorong penggunaan pasta remineralisasi setelah pemutihan gigi terutama di gigi muda permanen yang enamelnya masih dalam proses maturasi pasca-erupsi. Tujuan

  12. Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period

    Science.gov (United States)

    ERDEMİR, Ugur; YİLDİZ, Esra; EREN, Meltem Mert; OZEL, Sevda

    2013-01-01

    Objectives: This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. Material and Methods: A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group). For the control groups, the specimens were stored in distilled water for 24 hours at 37º C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05). Results: Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (phardness values of the restorative materials was tested using Bonferroni's multiple comparison tests, and it was observed that specimens stored in distilled water demonstrated statistically significant lower mean surface hardness reductions when compared to the specimens immersed in sports and energy drinks after a 1-month evaluation period (phardness of a restorative material depends on the duration of exposure time, and the composition of the material. PMID:23739850

  13. 30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Distinctively colored hard hats, or hard caps... STANDARDS-UNDERGROUND COAL MINES Miscellaneous § 75.1720-1 Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

  14. 30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Distinctively colored hard hats or hard caps... Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color from those worn by experienced miners shall be worn at...

  15. Application specific Tester-On-a-Resident-Chip (TORCH{trademark}) - innovation in the area of semiconductor testing

    Energy Technology Data Exchange (ETDEWEB)

    Bowles, M. [L& M Technologies, Albuquerque, NM (United States); Peterson, T. [New Mexico Highlands Univ., Las Vegas, NM (United States); Savignon, D.; Campbell, D. [Sandia National Labs., Albuquerque, NM (United States)

    1997-12-01

    Manufacturers widely recognize testing as a major factor in the cost, producability, and delivery of product in the $100 billion integrated circuit business: {open_quotes}The rapid development of VLSI using sub-micron CMOS technology has suddenly exposed traditional test techniques as a major cost factor that could restrict the development of VLSI devices exceeding 512 pins an operating frequencies above 200 MHz.{close_quotes} -- 1994 Semiconductor Industry Association Roadmap, Design and Test, Summary, pg. 43. This problem increases dramatically for stockpile electronics, where small production quantities make it difficult to amortize the cost of increasingly expensive testers. Application of multiple ICs in Multi-Chip Modules (MCM) greatly multiplies testing problems for commercial and defense users alike. By traditional test methods, each new design requires custom test hardware and software and often dedicated testing equipment costing millions of dollars. Also, physical properties of traditional test systems often dedicated testing equipment costing millions of dollars. Also, physical properties of traditional test systems limit capabilities in testing at-speed (>200 MHz), high-impedance, and high-accuracy analog signals. This project proposed a revolutionary approach to these problems: replace the multi-million dollar external test system with an inexpensive test system integrated onto the product wafer. Such a methodology enables testing functions otherwise unachievable by conventional means, particularly in the areas of high-frequency, at-speed testing, high impedance analog circuits, and known good die assessment. The techniques apply specifically to low volume applications, typical of Defense Programs, where testing costs represent an unusually high proportional of product costs, not easily amortized.

  16. Investigation of Genetic Control of Traits Related to Salinity Tolerance in Rice Seedling Using Line × Tester Method

    Directory of Open Access Journals (Sweden)

    H. Sabouri

    2011-05-01

    Full Text Available After wheat, rice is the second most important cereal grown in Iran that improvement of its economical characteristics always has important role in the rice breeding programs. In order to estimate the genetic parameters and identify salt-tolerant varieties and hybrids in seedling stage, seven female parents (Shah-pasand, Gharib, Tarom Mahalli, Ahlami Tarom, Hashemi and Dom Sepid and four male parents (Khazar, Sepidroud, Dorfak and IR28 were crossed in a Line × tester mating design and their progenies were evaluated for traits related to salinity tolerance in Physiology Laboratory of Gonbad Kavous University. These traits include genetic code, chlorophyll content, root and shoot length, dry weight of root and shoot, sodium and potassium percentage in roots and shoots, ratio of sodium to potassium in roots and shoots and the percentage of seedlings’ stand. The results showed both additive and non-additive effects are involved in seedlings’ traits under salinity condition but non-additive effects play more important role in the genetic control of the traits. In this study, it was found that varieties of Hashemi (-0.101, Gharib (-0.284, Tarom Mahalli (-0.326, Sepidroud (-0.562 and Dorfak (-0.164 which possess good general combining ability are suitable for transferring more desirable genetic code and the higher percentage of seedlings stand and could be used in breeding programs to reduce the genetic code and increase the seedlings’ stand under salinity stress. In addition, investigation of specific combining ability for morphological and physiological characteristics showed that among the 28 crosses, three hybrids of Sepidroud×Ahlami Tarom, Dorfak×Hashemi and Dorfak×Sepidroud could be suitable for the breeding programs of salinity tolerance in seedling stage.

  17. Tale of two hard Pomerons

    CERN Document Server

    Berera, A

    2000-01-01

    Two mechanisms are examined for hard double "pomeron" exchange dijet production, the factorized model of Ingelman-Schlein, and the nonfactorized model of lossless jet production which exhibits the Collins-Frankfurt-Strikman mechanism. Comparisons between these two mechanisms are made of the total cross section, E/sub T/ spectra, and mean rapidity spectra. For both mechanisms, several specific models are examined with the cuts of the collider detector at Fermilab (CDF) , DOE, and representative cuts of CERN LHC. Distinct qualitative differences are predicted by the two mechanisms for the CDF y/sub +/ spectra and for the E/sub T/ spectra for all three experimental cuts. The preliminary CDF and DOE experimental data for this process are interpreted in terms of these two mechanisms. The y/sub +/ spectra of the CDF data are suggestive of domination by the factorized Ingelman- Schlein mechanism, whereas the DOE data show no greater preference for either mechanism. An inconsistency is found among all the theoretical...

  18. CAPSULE REPORT: HARD CHROME FUME ...

    Science.gov (United States)

    All existing information which includes the information extrapolated from the Hard Chrome Pollution Prevention Demonstration Project(s) and other sources derived from plating facilities and industry contacts, will be condensed and featured in this document. At least five chromium emission prevention/control devices have been tested covering a wide spectrum of techniques currently in use at small and large-sized chrome metal plating shops. The goal for limiting chromium emissions to levels specified in the MACT Standards are: (1) 0.030 milligrams per dry standard cubic meter of air (mg/dscm) for small facilities with existing tanks, (2) 0.015 mg/dscm for small facilities with new tanks or large facilities with existing or new tanks. It should be emphasized that chemical mist suppressants still have quality issues and work practices that need to be addressed when they are used. Some of the mist suppressants currently in use are: one-, two-, and three-stage mesh pad mist eliminators; composite mesh pad mist eliminators; packed-bed scrubbers and polyballs. This capsule report should, redominantly, emphasize pollution prevention techniques and include, but not be restricted to, the afore-mentioned devices. Information

  19. Hard disks with SCSI interface

    CERN Document Server

    Denisov, O Yu

    1999-01-01

    The testing of 20 models of hard SCSI-disks is carried out: the Fujitsu MAE3091LP; the IBM DDRS-39130, DGHS-318220, DNES-318350, DRHS-36V and DRVS-18V; the Quantum Atlas VI 18.2; the Viking 11 9.1; the Seagate ST118202LW, ST118273LW, ST118273W, ST318203LW, ST318275LW, ST34520W, ST39140LW and ST39173W; and the Western Digital WDE9100-0007, WDE9100-AV0016, WDE9100-AV0030 and WDE9180-0048. All tests ran under the Windows NT 4.0 workstation operating system with Service Pack 4, under video mode with 1024*768 pixel resolution, 32- bit colour depth and V-frequency equal to 85 Hz. The detailed description and characteristics of SCSI stores are presented. Test results (ZD Winstone 99 and ZD WinBench 99 tests) are given in both table and diagram (disk transfer rate) forms. (0 refs).

  20. ERRATUM: Work smart, wear your hard hat

    CERN Multimedia

    2003-01-01

    An error appeared in the article «Work smart, wear your hard hat» published in Weekly Bulletin 27/2003, page 5. The impact which pierced a hole in the hard hat worn by Gerd Fetchenhauer was the equivalent of a box weighing 5 kg and not 50 kg.

  1. Retraction of Hard, Lozano, and Tversky (2006)

    Science.gov (United States)

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

    2008-01-01

    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…

  2. 21 CFR 133.150 - Hard cheeses.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Hard cheeses. 133.150 Section 133.150 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... or plant origin capable of aiding in the curing or development of flavor of hard cheese may be added...

  3. The effectiveness of betel leaf (Piper betle Linn extract gel and cocoa bean (Theobroma cacao L extract gel application against the hardness of enamel surface in vitro.

    Directory of Open Access Journals (Sweden)

    Juni Jekti Nugroho

    2017-04-01

    Full Text Available Objective : Nowadays several ways  have been evolved  to increase the hardness of the enamel surface as an effort to prevent caries. One of the alternatives that can be used is application of gel with herbal basic material. Material and Methods : The use of herbal basic material is preferred by people because the side effects are relatively small compared to synthetic drugs. Piper betle and cocoa beans are medicinal plants that is often used by people to inhibit caries. This is because piper betle and cocoa beans contain hardness that may influence the enamel surface. The purpose of this research was to determine the effect of piper betle extract gel and cocoa bean extract gel against the hardness of enamel surface. The samples, maxillary first premolar teeth, which has been extracted and does not have caries, were divided into 3 treatment groups: piper betle extract gel, cocoa bean extract gel, and distilled water as a negative control. Each treatment group consisted of 8 samples. The samples are decoronated in cemento-enamel junction (CEJ areas and planted on orthoplast blocks with labial surface facing up. Samples were applied in labial enamel surface to 5, 15 and 35 minutes period times. Samples before and after the application in each treatment group were measured using Universal Hardness Tester. Data were collected and analyzed using ANNOVA Repeated test. Results : Showed there were significant differences (p 0.05 of enamel surface hardness before and after the application of piper betel extract gel and distilled water. Conclusion : Therefore it can be concluded that cocoa been extract gel is more effective to increase the hardness of email surface.

  4. Assessing Hepatitis C Burden and Treatment Effectiveness through the British Columbia Hepatitis Testers Cohort (BC-HTC: Design and Characteristics of Linked and Unlinked Participants.

    Directory of Open Access Journals (Sweden)

    Naveed Zafar Janjua

    Full Text Available The British Columbia (BC Hepatitis Testers Cohort (BC-HTC was established to assess and monitor hepatitis C (HCV epidemiology, cost of illness and treatment effectiveness in BC, Canada. In this paper, we describe the cohort construction, data linkage process, linkage yields, and comparison of the characteristics of linked and unlinked individuals.The BC-HTC includes all individuals tested for HCV and/or HIV or reported as a case of HCV, hepatitis B (HBV, HIV or active tuberculosis (TB in BC linked with the provincial health insurance client roster, medical visits, hospitalizations, drug prescriptions, the cancer registry and mortality data using unique personal health numbers. The cohort includes data since inception (1990/1992 of each database until 2012/2013 with plans for annual updates. We computed linkage rates by year and compared the characteristics of linked and unlinked individuals.Of 2,656,323 unique individuals available in the laboratory and surveillance data, 1,427,917(54% were included in the final linked cohort, including about 1.15 million tested for HCV and about 1.02 million tested for HIV. The linkage rate was 86% for HCV tests, 89% for HCV cases, 95% for active TB cases, 48% for HIV tests and 36% for HIV cases. Linkage rates increased from 40% for HCV negatives and 70% for HCV positives in 1992 to ~90% after 2005. Linkage rates were lower for males, younger age at testing, and those with unknown residence location. Linkage rates for HCV testers co-infected with HIV, HBV or TB were very high (90-100%.Linkage rates increased over time related to improvements in completeness of identifiers in laboratory, surveillance, and registry databases. Linkage rates were higher for HCV than HIV testers, those testing positive, older individuals, and females. Data from the cohort provide essential information to support the development of prevention, care and treatment initiatives for those infected with HCV.

  5. Assessing Hepatitis C Burden and Treatment Effectiveness through the British Columbia Hepatitis Testers Cohort (BC-HTC): Design and Characteristics of Linked and Unlinked Participants.

    Science.gov (United States)

    Janjua, Naveed Zafar; Kuo, Margot; Chong, Mei; Yu, Amanda; Alvarez, Maria; Cook, Darrel; Armour, Rosemary; Aiken, Ciaran; Li, Karen; Mussavi Rizi, Seyed Ali; Woods, Ryan; Godfrey, David; Wong, Jason; Gilbert, Mark; Tyndall, Mark W; Krajden, Mel

    2016-01-01

    The British Columbia (BC) Hepatitis Testers Cohort (BC-HTC) was established to assess and monitor hepatitis C (HCV) epidemiology, cost of illness and treatment effectiveness in BC, Canada. In this paper, we describe the cohort construction, data linkage process, linkage yields, and comparison of the characteristics of linked and unlinked individuals. The BC-HTC includes all individuals tested for HCV and/or HIV or reported as a case of HCV, hepatitis B (HBV), HIV or active tuberculosis (TB) in BC linked with the provincial health insurance client roster, medical visits, hospitalizations, drug prescriptions, the cancer registry and mortality data using unique personal health numbers. The cohort includes data since inception (1990/1992) of each database until 2012/2013 with plans for annual updates. We computed linkage rates by year and compared the characteristics of linked and unlinked individuals. Of 2,656,323 unique individuals available in the laboratory and surveillance data, 1,427,917(54%) were included in the final linked cohort, including about 1.15 million tested for HCV and about 1.02 million tested for HIV. The linkage rate was 86% for HCV tests, 89% for HCV cases, 95% for active TB cases, 48% for HIV tests and 36% for HIV cases. Linkage rates increased from 40% for HCV negatives and 70% for HCV positives in 1992 to ~90% after 2005. Linkage rates were lower for males, younger age at testing, and those with unknown residence location. Linkage rates for HCV testers co-infected with HIV, HBV or TB were very high (90-100%). Linkage rates increased over time related to improvements in completeness of identifiers in laboratory, surveillance, and registry databases. Linkage rates were higher for HCV than HIV testers, those testing positive, older individuals, and females. Data from the cohort provide essential information to support the development of prevention, care and treatment initiatives for those infected with HCV.

  6. Behavioral intention to take up different types of HIV testing among men who have sex with men who were never-testers in Hong Kong.

    Science.gov (United States)

    Wang, Zixin; Lau, Joseph T F; She, Rui; Ip, Mary; Jiang, Hui; Ho, Shara P Y; Yang, XueYing

    2018-01-01

    Human immunodeficiency virus (HIV) testing is an important global prevention strategy but underutilized by local men who have sex with men (MSM). This study investigated the prevalence of behavioral intention to take up HIV testing (specific or any type), in the next six months among MSM who had not been tested for HIV in the last three years (never-testers) in Hong Kong. The data was based on 141 never-testers of 430 MSM who completed the anonymous baseline telephone survey of an ongoing randomized controlled trial from January 2015 to August 2015. Only 17.7% of them showed strong intention to take up any type of HIV testing in the next six months. Adjusted analysis showed that perceived benefit of HIV testing (adjusted odds ratio [AOR]: 1.29, 95% confidence interval [CI]: 1.01, 1.66), perceived psychological barriers of HIV testing (AOR: 0.85, 95%CI: 0.73, 1.00), and perceived self-efficacy in taking up HIV testing (AOR: 1.28, 95%CI: 1.07, 1.52) were significantly associated with behavioral intention to take up any HIV testing. Perceived cue to action from non-governmental organization staff was positively associated with a marginal p-value of 0.077 (AOR: 2.37, 95%CI: 0.97, 5.77). It is warranted to strengthen perceived benefit, remove psychological barriers, and increase perceived self-efficacy related to HIV testing. Innovative and effective health promotions are greatly needed to increase HIV testing coverage among never-testers.

  7. Measurement of local strain-induced martensitic phase transformation by micro-hardness; Bisho kodo wo mochiita kyokusho hizumi yuki martensite hentai tokusei no sokutei

    Energy Technology Data Exchange (ETDEWEB)

    Shibutani, Y.; Taniyama, A.; Tomita, Y.; Adachi, T. [Kobe University, Kobe (Japan). Faculty of Engineering

    1997-08-15

    By the duplex effect produced by two kinds of phases of austenite and martensite, the transformation-induced plasticity (TRIP) steel is improved in ductility and fracture toughness. The strain-induced martensitic phase transformation could be associated with the strain localization behavior. Accordingly, the measurement of the amount of local transformation is necessary in order to construct a more physical evolution model in the constitutive equation. In this study, a new measurement system using a micro-hardness tester is proposed to obtain a volume fraction map of the martensitic phase expanding in the neighbor of strain localization. Then the system is applied to investigate the inhomogenous transformation behavior around the notch root of SUS 304 stainless steel bar under uniaxial tension. 27 refs., 11 figs., 1 tab.

  8. [Influence of different ultrasonic irrigation solutions after root canal preparation with ProTaper by machine on micro-hardness of root canal dentin].

    Science.gov (United States)

    Guo, Jiang-li; Zhang, Yan; Zhen, Lei

    2015-08-01

    To develope the influence of different ultrasonic irrigations after root canal preparation with nickel titanium ProTaper on micro-hardness of root canal dentin. Sixty of maxillary anterior teeth with single-canal were collected and randomly divided into 6 groups. Group A was control group, group B was prepared to F3 with nickel titanium ProTaper by machine, group C was ultrasonic irrigated with 3% hydrogen peroxide solution for 1 minute after preparation, group D was ultrasonic irrigated with koutai mouthwash for 1 minute after preparation, group E was ultrasonic irrigated with 17% EDTA solution for 1 minute after preparation, group F was ultrasonic irrigated with distilled water for 1 minute after preparation. The roots were then sectioned horizontally into 3 parts, split longitudinally into halves and examined under a micro Vickers hardness test machine. The data was analyzed by one-way ANOVA and t test with SPSS 17.0 software package. The micro-hardness of group A was (52.66 ± 1.64) HV,(52.08 ± 1.53) HV and (51.47 ± 2.53) HV. There was no significant difference in all parts of the root canal in group A (P>0.05). The micro-hardness of the apical third of root canal was lower than that of the cervical and middle of root canal in the other groups (Phardness of group E was (44.65 ± 1.33) HV and(42.55 ± 1.12) HV, and there were statistical significances between group E and the other groups (Phardness of group E was (37.82 ± 1.60) HV, and group C was (44.14±1.73) HV, both of the comparative differences with other groups were statistically significant (P0.05). Root canal preparation to F3 with nickel titanium ProTaper by machine can make the micro-hardness of the apical third of root canal decrease. Ultrasonic irrigation with 17% EDTA solution for 1 minute can make the micro-hardness of the root canal decrease ultrasonic irrigation with. Ultrasonic irrigation with 3% hydrogen peroxide can make the micro-hardness of the apical third of root canal decrease

  9. Sheet electron beam tester

    Science.gov (United States)

    Spear, Alexander Grenbeaux

    The DARPA HiFIVE project uses a pulsed electron sheet beam gun to power a traveling wave tube amplifier operating at 220 GHz. Presented is a method for characterizing the high current density 0.1 mm by 1 mm sheet electron beam. A tungsten tipped probe was scanned through the cross section of the sheet electron beam inside of a vacuum vessel. The probe was controlled with sub-micron precision using stepper motors and LabView computer control while boxcar averaging hardware sampled the pulsed beam. Matlab algorithms were used to interpret the data, calculate beam dimensions and current density, and create 2-dimensional cross section images. Full characterization of two separate HiFIVE sheet electron guns was accomplished and is also presented.

  10. Hearing Aid Tester

    Science.gov (United States)

    1978-01-01

    Hearing aids often develop malfunctions that are not detected by the wearer. This is particularly true when the wearers are school-age children. Studies of selected groups showed that from 30 to more than 50 percent of school children were not getting adequate benefit from their hearing aids because of unrecognized malfunctions, usually low or dead batteries. This can be serious because hearing impairment retards a child's educational progress. NASA technology incorporated in the Hearing Aid Malfunction Detection Unit (HAMDU), the device pictured, is expected to provide an effective countermeasure to the childrens' hearing aid problem. A patent license has been awarded to a minority-owned firm, Hopkins International Company, a subsidiary of H. H. Aerospace Design Co., Inc., Elmford, New York. The company plans early commercial availability of its version of the device.

  11. Hearing-aid tester

    Science.gov (United States)

    Kessinger, R.; Polhemus, J. T.; Waring, J. G.

    1977-01-01

    Hearing aids are automatically checked by circuit that applies half-second test signal every thirty minutes. If hearing-aid output is distorted, too small, or if battery is too low, a warning lamp is activated. Test circuit is incorporated directly into hearing-aid package.

  12. Trust in Testers

    Science.gov (United States)

    White, John

    2013-01-01

    It is time to replace the examination regime at 16 and 18 by something more appropriate. The coalition government has been solidifying its place by its Baccalaureate reforms at both ages, but this is a move in quite the wrong direction. Whatever the wider purposes that the examination system may serve, its core aim is to find out how well students…

  13. DEFLECTION PRESSURE TESTER

    Science.gov (United States)

    Cooper, C.M.

    1961-01-01

    A method and apparatus for determining whether the jacket of a nuclear- fuel slug has a leak are described. The region of the jacket to be leak-tested is sealed off, and gas under pressure is applied thereto. If there is an imperfection, the gas will enter the jacket and bulge another region of the jacket. The bulge occurring is measured by a gage.

  14. Electrical Circuit Tester

    Science.gov (United States)

    Love, Frank

    2006-04-18

    An electrical circuit testing device is provided, comprising a case, a digital voltage level testing circuit with a display means, a switch to initiate measurement using the device, a non-shorting switching means for selecting pre-determined electrical wiring configurations to be tested in an outlet, a terminal block, a five-pole electrical plug mounted on the case surface and a set of adapters that can be used for various multiple-pronged electrical outlet configurations for voltages from 100 600 VAC from 50 100 Hz.

  15. Two-stage Lagrangian modeling of ignition processes in ignition quality tester and constant volume combustion chambers

    KAUST Repository

    Alfazazi, Adamu

    2016-08-10

    The ignition characteristics of isooctane and n-heptane in an ignition quality tester (IQT) were simulated using a two-stage Lagrangian (TSL) model, which is a zero-dimensional (0-D) reactor network method. The TSL model was also used to simulate the ignition delay of n-dodecane and n-heptane in a constant volume combustion chamber (CVCC), which is archived in the engine combustion network (ECN) library (http://www.ca.sandia.gov/ecn). A detailed chemical kinetic model for gasoline surrogates from the Lawrence Livermore National Laboratory (LLNL) was utilized for the simulation of n-heptane and isooctane. Additional simulations were performed using an optimized gasoline surrogate mechanism from RWTH Aachen University. Validations of the simulated data were also performed with experimental results from an IQT at KAUST. For simulation of n-dodecane in the CVCC, two n-dodecane kinetic models from the literature were utilized. The primary aim of this study is to test the ability of TSL to replicate ignition timings in the IQT and the CVCC. The agreement between the model and the experiment is acceptable except for isooctane in the IQT and n-heptane and n-dodecane in the CVCC. The ability of the simulations to replicate observable trends in ignition delay times with regard to changes in ambient temperature and pressure allows the model to provide insights into the reactions contributing towards ignition. Thus, the TSL model was further employed to investigate the physical and chemical processes responsible for controlling the overall ignition under various conditions. The effects of exothermicity, ambient pressure, and ambient oxygen concentration on first stage ignition were also studied. Increasing ambient pressure and oxygen concentration was found to shorten the overall ignition delay time, but does not affect the timing of the first stage ignition. Additionally, the temperature at the end of the first stage ignition was found to increase at higher ambient pressure

  16. Inter-tester reproducibility and inter-method agreement of two variations of the Beighton test for determining Generalised Joint Hypermobility in primary school children.

    Science.gov (United States)

    Junge, Tina; Jespersen, Eva; Wedderkopp, Niels; Juul-Kristensen, Birgit

    2013-12-21

    The assessment of Generalised Joint Hypermobility (GJH) is usually based on the Beighton tests, which consist of a series of nine tests. Possible methodological shortcomings can arise, as the tests do not include detailed descriptions of performance, interpretation nor classification of GJH. The purpose of this study was, among children aged 7-8 and 10-12 years, to evaluate: 1) the inter-tester reproducibility of the tests and criteria for classification of GJH for 2 variations of the Beighton test battery (Methods A and B) with a variation in starting positions and benchmarks between methods, and 2) the inter-method agreement for the two batteries. A standardised three-phase protocol for clinical reproducibility studies was followed including a training phase, an overall agreement phase and a study phase. The number of participants in the three phases was 10, 70 and 39 respectively. For the inter-method study a total of 103 children participated. Two testers judged each test battery. A score of ≥ 5 was set as the cut-off level for GJH. Cohen's kappa statistics and McNemar's test were used to test for agreement and significant differences. Kappa values for GJH (≥ 5) were 0.64 (Method A, prevalence 0.42) and 0.59 (Method B, prevalence 0.46), with no difference between testers in Method A (p = 0.45) and B (p = 0.29). Prevalence of GJH in the inter-method study was 31% (A) and 35% (B) with no difference between methods (p = 0.54). Inter-tester reproducibility of Methods A and B was moderate to substantial, when following a standardised study protocol. Both test batteries can be used in the same children population, as there was no difference in prevalence of GJH at cut point 5, when applying method A and B. However, both methods need to be tested for their predictive validity at higher cut-off levels, e.g. ≥ 6 and ≥ 7.

  17. Analysis of Hard Thin Film Coating

    Science.gov (United States)

    Shen, Dashen

    1998-01-01

    MSFC is interested in developing hard thin film coating for bearings. The wearing of the bearing is an important problem for space flight engine. Hard thin film coating can drastically improve the surface of the bearing and improve the wear-endurance of the bearing. However, many fundamental problems in surface physics, plasma deposition, etc, need further research. The approach is using electron cyclotron resonance chemical vapor deposition (ECRCVD) to deposit hard thin film an stainless steel bearing. The thin films in consideration include SiC, SiN and other materials. An ECRCVD deposition system is being assembled at MSFC.

  18. Radiation Hard High Performance Optoelectronic Devices Project

    Data.gov (United States)

    National Aeronautics and Space Administration — High-performance, radiation-hard, widely-tunable integrated laser/modulator chip and large-area avalanche photodetectors (APDs) are key components of optical...

  19. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... Drugs So Hard to Quit? National Institute on Drug Abuse (NIDA/NIH) Loading... Unsubscribe from National Institute on Drug Abuse (NIDA/NIH)? Cancel Unsubscribe Working... Subscribe Subscribed Unsubscribe ...

  20. Why Are Drugs So Hard to Quit?

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    Full Text Available ... it free Find out why Close Why Are Drugs So Hard to Quit? National Institute on Drug Abuse (NIDA/NIH) Loading... Unsubscribe from National Institute on Drug Abuse (NIDA/NIH)? Cancel Unsubscribe Working... Subscribe Subscribed ...

  1. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... drugs is hard because addiction is a brain disease. Your brain is like a control tower that ... 3:46 Dr. Nora Volkow on Addiction: A Disease of Free Will - Duration: 21:12. National Institute ...

  2. Macroindentation hardness measurement-Modernization and applications.

    Science.gov (United States)

    Patel, Sarsvat; Sun, Changquan Calvin

    2016-06-15

    In this study, we first developed a modernized indentation technique for measuring tablet hardness. This technique is featured by rapid digital image capture, using a calibrated light microscope, and precise area-determination. We then systematically studied effects of key experimental parameters, including indentation force, speed, and holding time, on measured hardness of a very soft material, hydroxypropyl cellulose, and a very hard material, dibasic calcium phosphate, to cover a wide range of material properties. Based on the results, a holding period of 3min at the peak indentation load is recommended to minimize the effect of testing speed on H. Using this method, we show that an exponential decay function well describes the relationship between tablet hardness and porosity for seven commonly used pharmaceutical powders investigated in this work. We propose that H and H at zero porosity may be used to quantify the tablet deformability and powder plasticity, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... navigation Sign in Search Loading... Close Yeah, keep it Undo Close This video is unavailable. Watch Queue ... changes the signals in your brain and makes it hard to feel OK without the drug. This ...

  4. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... now. Please try again later. Published on Feb 7, 2012 Quitting drugs is hard because addiction is ... is wrong | Johann Hari - Duration: 14:43. TED 3,569,239 views 14:43 Addiction - Duration: 5: ...

  5. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... Search Loading... Close Yeah, keep it Undo Close This video is unavailable. Watch Queue Queue Watch Queue Queue Remove ... Queue __count__/__total__ Find out why Close Why Are Drugs So Hard to Quit? National Institute on ...

  6. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... Close Yeah, keep it Undo Close This video is unavailable. Watch Queue Queue Watch Queue Queue Remove ... total__ Find out why Close Why Are Drugs So Hard to Quit? National Institute on Drug Abuse ( ...

  7. Why Are Drugs So Hard to Quit?

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    Full Text Available ... out why Close Why Are Drugs So Hard to Quit? National Institute on Drug Abuse (NIDA/NIH) ... Unsubscribe 6K Loading... Loading... Working... Add to Want to watch this again later? Sign in to add ...

  8. Optical waveguides in hard crystalline materials

    NARCIS (Netherlands)

    Pollnau, Markus

    2005-01-01

    The recent results of our research group and collaborators in the field of fabrication, characterization, and applications of optical waveguides in hard crystalline materials, specifically in sapphire and Ti:sapphire, are reviewed.

  9. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... later? Sign in to add this video to a playlist. Sign in Share More Report Need to ... 2012 Quitting drugs is hard because addiction is a brain disease. Your brain is like a control ...

  10. Why Are Drugs So Hard to Quit?

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    Full Text Available ... out why Close Why Are Drugs So Hard to Quit? National Institute on Drug Abuse (NIDA/NIH) ... 6.2K Loading... Loading... Working... Add to Want to watch this again later? Sign in to add ...

  11. Double hard scattering without double counting

    Science.gov (United States)

    Diehl, Markus; Gaunt, Jonathan R.; Schönwald, Kay

    2017-06-01

    Double parton scattering in proton-proton collisions includes kinematic regions in which two partons inside a proton originate from the perturbative splitting of a single parton. This leads to a double counting problem between single and double hard scattering. We present a solution to this problem, which allows for the definition of double parton distributions as operator matrix elements in a proton, and which can be used at higher orders in perturbation theory. We show how the evaluation of double hard scattering in this framework can provide a rough estimate for the size of the higher-order contributions to single hard scattering that are affected by double counting. In a numeric study, we identify situations in which these higher-order contributions must be explicitly calculated and included if one wants to attain an accuracy at which double hard scattering becomes relevant, and other situations where such contributions may be neglected.

  12. Double hard scattering without double counting

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, Markus [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Gaunt, Jonathan R. [VU Univ. Amsterdam (Netherlands). NIKHEF Theory Group; Schoenwald, Kay [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2017-02-15

    Double parton scattering in proton-proton collisions includes kinematic regions in which two partons inside a proton originate from the perturbative splitting of a single parton. This leads to a double counting problem between single and double hard scattering. We present a solution to this problem, which allows for the definition of double parton distributions as operator matrix elements in a proton, and which can be used at higher orders in perturbation theory. We show how the evaluation of double hard scattering in this framework can provide a rough estimate for the size of the higher-order contributions to single hard scattering that are affected by double counting. In a numeric study, we identify situations in which these higher-order contributions must be explicitly calculated and included if one wants to attain an accuracy at which double hard scattering becomes relevant, and other situations where such contributions may be neglected.

  13. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... Feb 7, 2012 Quitting drugs is hard because addiction is a brain disease. Your brain is like ... out signals to direct your actions and choices. Addiction changes the signals in your brain and makes ...

  14. Laser Ablatin of Dental Hard Tissue

    Energy Technology Data Exchange (ETDEWEB)

    Seka, W.; Rechmann, P.; Featherstone, J.D.B.; Fried, D.

    2007-07-31

    This paper discusses ablation of dental hard tissue using pulsed lasers. It focuses particularly on the relevant tissue and laser parameters and some of the basic ablation processes that are likely to occur. The importance of interstitial water and its phase transitions is discussed in some detail along with the ablation processes that may or may not directly involve water. The interplay between tissue parameters and laser parameters in the outcome of the removal of dental hard tissue is discussed in detail.

  15. Soft versus hard nanoparticles in the delivery of aromatic ...

    African Journals Online (AJOL)

    McRoy

    coated hard nanoparticles). E) Nanoparticles with compact core covered by a porous material with the photosensitisers covalently bonded (hybrid nanoparticles and silica-coated hard nanoparticles). The first attempt to target hard nanoparticles.

  16. Standard test methods for rockwell hardness of metallic materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 These test methods cover the determination of the Rockwell hardness and the Rockwell superficial hardness of metallic materials by the Rockwell indentation hardness principle. This standard provides the requirements for Rockwell hardness machines and the procedures for performing Rockwell hardness tests. 1.2 This standard includes additional requirements in annexes: Verification of Rockwell Hardness Testing Machines Annex A1 Rockwell Hardness Standardizing Machines Annex A2 Standardization of Rockwell Indenters Annex A3 Standardization of Rockwell Hardness Test Blocks Annex A4 Guidelines for Determining the Minimum Thickness of a Test Piece Annex A5 Hardness Value Corrections When Testing on Convex Cylindrical Surfaces Annex A6 1.3 This standard includes nonmandatory information in appendixes which relates to the Rockwell hardness test. List of ASTM Standards Giving Hardness Values Corresponding to Tensile Strength Appendix X1 Examples of Procedures for Determining Rockwell Hardness Uncertainty Appendix X...

  17. Standard test methods for rockwell hardness of metallic materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 These test methods cover the determination of the Rockwell hardness and the Rockwell superficial hardness of metallic materials by the Rockwell indentation hardness principle. This standard provides the requirements for Rockwell hardness machines and the procedures for performing Rockwell hardness tests. 1.2 This standard includes additional requirements in annexes: Verification of Rockwell Hardness Testing Machines Annex A1 Rockwell Hardness Standardizing Machines Annex A2 Standardization of Rockwell Indenters Annex A3 Standardization of Rockwell Hardness Test Blocks Annex A4 Guidelines for Determining the Minimum Thickness of a Test Piece Annex A5 Hardness Value Corrections When Testing on Convex Cylindrical Surfaces Annex A6 1.3 This standard includes nonmandatory information in appendixes which relates to the Rockwell hardness test. List of ASTM Standards Giving Hardness Values Corresponding to Tensile Strength Appendix X1 Examples of Procedures for Determining Rockwell Hardness Uncertainty Appendix X...

  18. Evaluation of the surface hardness of composite resins before and after polishing at different times Avaliação da dureza superficial de resinas compostas antes e após o polimento em diferentes tempos

    Directory of Open Access Journals (Sweden)

    Michelle Alexandra Chinelatti

    2006-06-01

    Full Text Available PURPOSE: The aim of this study was to evaluate the surface hardness of six composite resins: Revolution, Natural Flow, Fill Magic Flow, Flow-it! (flowables, Silux Plus (microfilled and Z100 (minifilled before and after polishing at different times. MATERIALS AND METHODS: For this purpose, 240 specimens (5mm diameter, 1.4mm high were prepared. Vickers hardness was determined before and after polishing at different times: immediately, 24h, 7 and 21 days after preparation of the samples. Statistical analysis was performed by ANOVA and Tukey test. RESULTS: There was no difference in the hardness of flowable resins, which had lower hardness than the minifilled resin. The minifilled resin showed the highest surface hardness as compared to the other materials (pPROPOSIÇÃO: O objetivo deste estudo foi avaliar a dureza superficial de seis resinas compostas - Revolution, Natural Flow, Fill Magic Flow, Flow-it! (flowables, Silux Plus (micropartículas e Z100 (híbrida - antes e após o polimento realizado em diferentes tempos. MATERIAL E MÉTODO: Foram confeccionados 240 corpos-de-prova circulares (5mm de diâmetro e 1,4mm de altura. A dureza Vickers foi obtida antes e após o polimento realizado em diferentes tempos: imediatamente, 24 horas, 7 dias e 21 dias após a confecção do corpo-de-prova. Os dados foram analisados estatisticamente por meio da ANOVA e do Teste de Tukey. RESULTADOS: Não houve diferença entre as resinas compostas flowable, as quais apresentaram os menores valores de dureza. A resina composta híbrida demonstrou os melhores resultados. Todos os materiais exibiram aumento de dureza após a realização do polimento, que foi mais evidente após 7 dias. CONCLUSÃO: Pôde-se concluir que, independente do tipo de resina composta, a dureza superficial foi consideravelmente maior quando o polimento foi realizado 1 semana após a confecção dos corpos-de-prova.

  19. Hardness and elasticity of caries-affected and sound primary tooth dentin bonded with 4-META one-step self-etch adhesives

    Science.gov (United States)

    Hosoya, Yumiko; Tay, Franklin R.; Miyakoshi, Shoichi; Pashley, David H.

    2013-01-01

    Purpose This study evaluated the quality of the interface of sound and carious primary tooth dentin bonded with two 4-META one-step self-etch adhesives. Methods Twelve sound and twelve carious primary molars were bonded with AQ Bond Plus (AQBP; Sun Medical) or Hybrid Bond (HB; Sun Medical) and restored with Clearfil Protect Liner F (Kuraray Medical Inc.). After 24 hours of water immersion, the teeth were sectioned and polished. Resin-dentin interfaces were measured with a nano-indentation tester and hardness and Young’s modulus were calculated. Data were analyzed using one-way or two-ways ANOVA and Fisher’s PLSD test with α=0.05. Resin-dentin interfaces were also observed with SEM and TEM. Ammoniacal silver nitrate was used as a tracer for TEM observation. Results Hardness and Young’s modulus of the interfacial dentin were significantly lower than the underlying intact dentin except for the carious-AQBP group. However, there was no significant difference of hardness and Young's moduli of the interfacial dentin among all groups. TEM revealed extensive interfacial nanoleakage in sound dentin bonded with either AQBP or HB. For the carious teeth, nanoleakage was absent in the hybrid layers bonded with the two adhesives. However, extensive silver deposits were identified from the subsurface, porous caries-affected dentin. PMID:18795517

  20. Inter-tester Reliability in Classifying Acute and Subacute Low Back Pain Patients into Clinical Subgroups: A Comparison of Specialists and Non-Specialists. A Pilot Study.

    Science.gov (United States)

    Paatelma, Markku; Karvqnen, Eira; Heinqnen, Ari

    2009-01-01

    Many systems have been suggested for classifying low back pain (LBP); the most commonly used among physiotherapists involves a pathoanatomical/pathophysiological tissue classification system. Few studies have examined whether this form of classification of LBP disorders can be performed in a reliable manner between specialists with advanced training, or between specialists with advanced training and non-specialists who lack advanced training. The purpose of this paper was to examine the inter-tester reliability of two specialists, and the ability of a specialist and non-specialist to independently classify patients with LBP, utilizing clinical tests and history-based classification methods after a short educational course on the classification system. Subjects were acute or sub-acute patients with LBP who visited their occupational healthcare or municipal healthcare center. Inter-tester reliability between the specialist and non-specialists was at almost the same level: overall Kappa 0.60 (95%CI; 0.40 to 0.85), overall agreement 70%, as between the two specialists: overall Kappa 0.65 (95%CI; 0.33-0.86), overall agreement 77%. The findings suggest that a short educational course can provide rather reliable examination tools to allow non-specialized physiotherapists to classify patients according to tissue origination.

  1. Computational Fluid Dynamics Simulation of Hydrodynamics and Stresses in the PhEur/USP Disintegration Tester Under Fed and Fasted Fluid Characteristics.

    Science.gov (United States)

    Kindgen, Sarah; Wachtel, Herbert; Abrahamsson, Bertil; Langguth, Peter

    2015-09-01

    Disintegration of oral solid dosage forms is a prerequisite for drug dissolution and absorption and is to a large extent dependent on the pressures and hydrodynamic conditions in the solution that the dosage form is exposed to. In this work, the hydrodynamics in the PhEur/USP disintegration tester were investigated using computational fluid dynamics (CFD). Particle image velocimetry was used to validate the CFD predictions. The CFD simulations were performed with different Newtonian and non-Newtonian fluids, representing fasted and fed states. The results indicate that the current design and operating conditions of the disintegration test device, given by the pharmacopoeias, are not reproducing the in vivo situation. This holds true for the hydrodynamics in the disintegration tester that generates Reynolds numbers dissimilar to the reported in vivo situation. Also, when using homogenized US FDA meal, representing the fed state, too high viscosities and relative pressures are generated. The forces acting on the dosage form are too small for all fluids compared to the in vivo situation. The lack of peristaltic contractions, which generate hydrodynamics and shear stress in vivo, might be the major drawback of the compendial device resulting in the observed differences between predicted and in vivo measured hydrodynamics. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  2. Developing and Studying the Methods of Hard-Facing with Heat-Resisting High-Hardness Steels

    Science.gov (United States)

    Malushin, N. N.; Kovalev, A. P.; Valuev, D. V.; Shats, E. A.; Borovikov, I. F.

    2016-08-01

    The authors develop the methods of hard-facing of mining-metallurgic equipment parts with heat-resisting high-hardness steels on the base of plasma-jet hard-facing in the shielding-alloying nitrogen atmosphere.

  3. In vitro Comparison of the Effct Cola Beverage on Surface Hardness of Siloran-Based (p90 and Methyl Methacrylate-Based (p60 Composites

    Directory of Open Access Journals (Sweden)

    Z.Khamverdi

    2016-11-01

    Full Text Available Introduction: Th characteristics of a suitable restoration material is having acceptable mechanical properties, protecting teeth against decay and ease of use in clinics. Diet can affct properties of restorative materials in the mouth. Since amongst important properties of composite restorations are mechanical properties such as hardness, the aim of this study was evaluation of the effct of Coca-Cola Beverages on surface hardness of a silorane based p90( and methyl methacrylate p60( composites. Methods: In this experimental study, thirty disc-shaped specimens 5 × 2 mm( of each of methyl methacrylate based Filtek p60, 3M Dental Products, USA( and a silorane based Filtek p90, 3M Dental Products, USA( composite resins were prepared, according to manufacturers' instructions. Specimens were randomly divided to four groups as follows N = 15(: G1: Filtek p90 without exposure to Coca-Cola, G2: Filtek p90 with exposure to Coca-Cola, G3: Filtek p60 without expure to Coca-Cola, G4: Filtek p60 with expure to Coca-Cola. Th specimens were exposed to regular sof drinks Coca-Cola, Khoshgovar, Tehran, Iran( at room temperature for seven days with a frequency of three times daily for 20 minutes at a time. In the remaining times of the day, they were kept in distilled water. Thn, micro hardness measurements were made for each specimen with a Vickers hardness testing machine Buehler, Lake Bluff IL, USA( under 500 g of force for 15 seconds. Data were analyzed using SPSS 18 and independent t-test at a signifiance level of 0.05. Results: Micro hardness values of four groups were G1: 68.28 ± 2.65; G2:59.56 ± 6.61; G3: 93.5 ± 2.38; and G4:86.76 ± 5.47, respectively. Th results of this study showed that Coca-Cola reduces the surface hardness of the two composite materials P > 0.05(. Conclusions: Th results showed the hardness of both Filtek p90 and Filtek p60 composite signifiantly decreases with Coca-Cola but the reduction was equal.

  4. Preparation and Properties of Ti-TiN-Zr-ZrN Multilayer Films on Titanium Alloy Surface

    Directory of Open Access Journals (Sweden)

    LIN Song-sheng

    2017-06-01

    Full Text Available 24 cycles Ti-TiN-Zr-ZrN soft-hard alternating multilayer film was deposited on TC11 titanium alloy by vacuum cathodic arc deposition method. The structure and performance of the multilayer film, especially wear and sand erosion resistance were investigated by various analytical methods including pin on disc wear tester, sand erosion tester, 3D surface topography instrument, scanning electron microscopy (SEM, X-ray diffraction(XRD, micro-hardness tester and scratch adhesion tester. The results indicate that the Vickers-hardness of the multilayer film with thickness of 5.8μm can reach up to 28.10GPa. The adhesive strength of these coatings can be as high as 56N. Wear rate of the multilayer coated alloy is one order of magnitude smaller than bare one, which decreased from 7.06×10-13 m3·N-1·m-1 to 3.03×10-14m3·N-1·m-1. Multilayer films can play the role in hindering the extension of cracks, and thus sand erosion properties of the TC11 titanium alloy substrates are improved.

  5. Hardness and microstructural characterization of API 5L X70 steel pipes welded by HF/ERW process; Caracterizacao microestrutural e de dureza em tubos de aco API 5L X70 soldados pelo processo HF/ERW

    Energy Technology Data Exchange (ETDEWEB)

    Calcada, Mauricio Vieira; Voorwald, Herman Jacobus Cornelis; Nascimento, Marcelino Pereira do [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia

    2010-07-01

    The materials that stand in the manufacture of steel pipes are called API, that should have, high mechanical resistance, high corrosion resistance, high fatigue resistance, good weldability, and other properties. Thus, the purpose of this project was to evaluate the microstructure and hardness of welded joints by the HF/ERW process of API 5L X70 steel pipes. The microstructural analysis was performed using a surface finish with grit sizes from 220 to 25 {mu}m e polishing with diamond paste from 9 {mu}m to 0.05 {mu}m; the revelation was made with 3% Nital attack. The Vickers hardness was performed across the welded joint by 33 points to indentation. The results were: 80.5 {+-} 3.4% of ferrite and 19.5 {+-} 3.4% of perlite for microanalysis. As for hardness, the values were: 215.69 HV10 for weld line, 218.65 HV10 for ZTA and 218.95 HV10 for base metal. (author)

  6. On the linear hard sphere chain fluids

    Science.gov (United States)

    Chamoux, Antoine; Perera, Aurelien

    The thermodynamic and structural properties of linear hard sphere chain fluids are studied using geometrical properties of the single chain. This is an extension of the method recently proposed by the authors to study convex particle fluids. The validity of this application to non-convex particles is tested against other theories and the integral equations PY and HNC for which a new simpler solution method is proposed also. The cases of both tangent and fused hard sphere chains are examined. An accurate equation of state is proposed which is valid for both linear tangent hard spheres and fused hard spheres. A semi-analytical expression for the Ornstein-Zernike direct correlation function is proposed which compares well with PY and HNC numerical results. The orientational instabiilty of the isotropic fluid is examined for several cases. In particular the Flory conjecture for linear N -tangent hard sphere fluid which predicts the isotropic-nematic transition around N = 7 is confirmed by the integral equations results for the orientational instability criteria, whereas the present theory predicts an instability for smaller aspect ratio. The influence of chain flexibility on the equation of state is discussed, mainly in the context of very long chains. In particular, it is found that the expressions for the pressure proposed here can be valid also for fully flexible long chains.

  7. Escherichia coli MTC, a human NADPH P450 reductase competent mutagenicity tester strain for the expression of human cytochrome P450 isoforms 1A1, 1A2, 2A6, 3A4, or 3A5: catalytic activities and mutagenicity studies.

    NARCIS (Netherlands)

    Kranendonk, M.; Carreira, F.; Theisen, P.; Laires, A.; Fischer, C.W.; Rueff, J.; Estabrook, R.W.; Vermeulen, N.P.E.; Roda, R.

    1999-01-01

    We report here on the genetic engineering of four new Escherichia coli tester bacteria, coexpressing human CYP1A1, CYP2A6, CYP3A4 or CYP3A5 with human NADPH cytochrome P450 reductase (RED) by a biplasmid coexpression system, recently developed to express human CYP1A2 in the tester strain MTC. The

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

    Science.gov (United States)

    Mendick, Heather; Allen, Kim; Harvey, Laura

    2015-01-01

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

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

    Science.gov (United States)

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

    2005-01-01

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

  10. Polynomial algorithms that prove an NP-hard hypothesis implies an NP-hard conclusion

    NARCIS (Netherlands)

    Bauer, D.; Broersma, Haitze J.; Morgana, A.; Schmeichel, E.

    1999-01-01

    A number of results in Hamiltonian graph theory are of the form $\\mathcal{P}$$_{1}$ implies $\\mathcal{P}$$_{2}$, where $\\mathcal{P}$$_{1}$ is a property of graphs that is NP-hard and $\\mathcal{P}$$_{2}$ is a cycle structure property of graphs that is also NP-hard. Such a theorem is the well-known

  11. Radiation hardness of mass produced PWO crystals

    CERN Document Server

    Drobychev, G Yu; Auffray, Etiennette; Borisevich, A E; Lecoq, P; Ligun, V; Korzhik, M; Peigneux, J P; Singovsky, A V; Skadorov, V V

    2000-01-01

    The studies of the distribution of the induced absorption in the spectral region of scintillations for mass produced PWO crystals and kinetics recovery have been made at the Bogoroditsk Techno-Chemical Plant (BTCP) using a specially developed rapid analysis method and at CERN by tests at various facilities easy to compare with electrons beam damages easy to access in a close vicinity. A probability for crystals with poor radiation hardness to be installed into calorimeter and a probability for crystals with good radiation hardness to be rejected during certification are estimated. It is shown that instead of measurements of the loss of light yield transmitted through PWO crystals under the electron beam irradiation, it is possible to use a sampling based measurements method of radiation induced absorption of crystals, i.e. to control the PWO crystals distribution by their radiation hardness. 8 Refs.

  12. Potential health impacts of hard water

    Directory of Open Access Journals (Sweden)

    Pallav Sengupta

    2013-01-01

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

  13. Potential Health Impacts of Hard Water

    Science.gov (United States)

    Sengupta, Pallav

    2013-01-01

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

  14. Hard template synthesis of metal nanowires

    Directory of Open Access Journals (Sweden)

    Go eKawamura

    2014-11-01

    Full Text Available 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.

  15. Rad Hard Active Media For Calorimeters

    CERN Document Server

    Norbeck, E; Möller, A; Onel, Y

    2006-01-01

    Zero-degree calorimeters have limited space and extreme levels of radiation. A simple, low cost, radiation hard design uses tungstenmetal as the absorber and a suitable liquid as the ˇCerenkov radiator. In other applications a PPAC (Parallel Plate Avalanche Counter) operatingwith a suitable atmosphericpressure gas is an attractive active material for a calorimeter. It can be made radiation hard and has sufficient gain in the gas that no electronic components are needed near the detector. It works well even with the highest concentration of shower particles. For this pressure range, R134A (used in auto air conditioners) has many desirable features.

  16. Effects of aging temperature on electrical conductivity and hardness of Cu-3 at. pct Ti alloy aged in a hydrogen atmosphere

    KAUST Repository

    Semboshi, S.

    2011-08-01

    To improve the balance of the electrical conductivity and mechanical strength for dilute Cu-Ti alloys by aging in a hydrogen atmosphere, the influence of aging temperature ranging from 673 K to 773 K (400 °C to 500 °C) on the properties of Cu-3 at. pct Ti alloy was studied. The Vickers hardness increases steadily with aging time and starts to fall at 3 hours at 773 K (500 °C), 10 hours at 723 K (450 °C), or over 620 hours at 673 K (400 °C), which is the same as the case of conventional aging in vacuum. The maximum hardness increases from 220 to 236 with the decrease of aging temperature, which is slightly lower than aging at the same temperature in vacuum. The electrical conductivity at the maximum hardness also increases from 18 to 32 pct of pure copper with the decrease of the temperature, which is enhanced by a factor of 1.3 to 1.5 in comparison to aging in vacuum. Thus, aging at 673 K (400 °C) in a hydrogen atmosphere renders fairly good balance of strength and conductivity, although it takes nearly a month to achieve. The microstructural changes during aging were examined by transmission electron microscopy (TEM) and atom-probe tomography (APT), it was confirmed that precipitation of the Cu4Ti phase occurs first and then particles of TiH2 form as the third phase, thereby efficiently removing the Ti solutes in the matrix.

  17. Remodelación del probador de aceites WPOT 0.25/75; Remodelig of the WPOT0.25/75 oil tester

    Directory of Open Access Journals (Sweden)

    Ignat Pérez Almirall

    2011-02-01

    Full Text Available El objetivo fundamental de este trabajo es el rediseño del probador de aceites WPOT 0.25/75. Para estofue necesario rediseñar completamente todo su sistema de control y de protección pues el original ademásde estar constituido sobre la base de válvulas de vacío, no funcionaba ya que presentaba fallas en lossoportes aislantes de las mismas, fallas de dichas válvulas y fallas en la placa aislante que sirve desoporte a los componentes de los mecanismos de protección y control. Para solucionar estos problemasse diseñó un sistema de control con tiristores para la protección del equipo sustituyéndose por completoel obsoleto sistema de control a válvulas, lográndose un sistema de control seguro, confiable y de fáciloperación como para ser operado por personal con pocas habilidades.  The main objective of this paper is to remodel the WPOT 0.25/75 oil tester equipment. The originalequipment was made with vacuum valves, coupled on an insulated support. This equipment presentedseveral electrical failures on the insulated support and in the vacuum valves. In order to solve this problem,a new control and protecting system, using tiristor,  was designed . With this new design it was possibleto use this oil tester again. Moreover, the design offers better and new operating options useful for somespecial interesting tests.

  18. A novel sample selection strategy by near-infrared spectroscopy-based high throughput tablet tester for content uniformity in early-phase pharmaceutical product development.

    Science.gov (United States)

    Shi, Zhenqi; Hermiller, James G; Gunter, Thomas Z; Zhang, Xiaoyu; Reed, Dave E

    2012-07-01

    This article proposes a new sample selection strategy to simplify the traditional content uniformity (CU) test in early research and development (R&D) with improved statistical confidence. This strategy originated from the prescreening of a large amount of tablets by a near-infrared spectroscopy (NIRS)-based high-volume tablet tester to the selection of extreme tablets with highest, medium, and lowest content of active pharmaceutical ingredient (API) for further high-performance liquid chromatography (HPLC) test. The NIRS-based high-volume tablet tester was equipped with an internally developed and integrated automated bagging and labeling system, allowing the traceability of every individual tablet by its measured physical and chemical signatures. A qualitative NIR model was used to translate spectral information to a concentration-related metric, that is scores, which allowed the selection of those extreme tablets. This sample selection strategy of extreme tablets was shown to provide equivalent representation of CU in the process compared with the traditional CU test using a large number of random samples. Because it only requires reference tests on three extreme samples per stratified location, the time- and labor-saving nature of this strategy is advantageous for CU test in early R&D. The extreme sampling approach is also shown to outperform random sampling with respect to statistical confidence for representing the process variation. In addition, a chemometric approach, which utilizes only pure component raw materials to develop an NIRS model sensitive to API concentration, is discussed with the advantage that it does not require tablets at multiple API levels. Prospective applications of this sample selection strategy are also addressed. Copyright © 2012 Wiley Periodicals, Inc.

  19. Remember Hard but Think Softly: Metaphorical Effects of Hardness/Softness on Cognitive Functions

    Directory of Open Access Journals (Sweden)

    Jiushu Xie

    2016-09-01

    Full Text Available Previous studies have found that bodily stimulation, such as hardness, biases social judgment and evaluation via metaphorical association; however, it remains unclear whether bodily stimulation also affects cognitive functions, such as memory and creativity. The current study used metaphorical associations between hard and rigid and between soft and flexible in Chinese, to investigate whether the experience of hardness affected cognitive functions requiring either rigidity (memory or flexibility (creativity. In Experiment 1, we found that Chinese-speaking participants performed better at recalling previously memorized words while sitting on a hard-surface stool (the hard condition than a cushioned one (the soft condition. In Experiment 2, participants sitting on a cushioned stool outperformed those sitting on a hard-surface stool on a Chinese riddle task, which required creative/flexible thinking, but not on an analogical reasoning task, which required both rigid and flexible thinking. The results suggest the hardness experience affects cognitive functions that are metaphorically associated with rigidity and flexibility. They support the embodiment proposition that cognitive functions and representations could be grounded via metaphorical association in bodily states.

  20. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... loaded. Loading... Loading... Rating is available when the video has been rented. This feature is not available right now. Please try again later. Published on Feb 7, 2012 Quitting drugs is hard because addiction is a brain disease. Your brain is like a control tower that ...

  1. Hardness of approximation for Knapsack problems

    NARCIS (Netherlands)

    Buhrman, H.; Loff, B.; Torenvliet, L.

    2015-01-01

    We show various hardness results for knapsack and related problems; in particular we will show that unless the Exponential-Time Hypothesis is false, subset-sum cannot be approximated any better than with an FPTAS. We also provide new unconditional lower bounds for approximating knapsack in Ketan

  2. Systematic hardness measurements on single crystals and ...

    Indian Academy of Sciences (India)

    Unknown

    Indian Academy of Sciences. 203. Systematic hardness measurements on single crystals and polycrystalline blanks of cesium halides. D B SIRDESHMUKH*, P GEETA KRISHNA and K G SUBHADRA. Department of Physics, Kakatiya University, Warangal 506 009, India. MS received 1 June 2001; revised 29 March 2002.

  3. Hardness of approximation for strip packing

    DEFF Research Database (Denmark)

    Adamaszek, Anna Maria; Kociumaka, Tomasz; Pilipczuk, Marcin

    2017-01-01

    -dimensional knapsack. In this article, we answer this question in negative by proving that it is NP-hard to approximate strip packing within a factor better than 12/11, even when restricted to polynomially bounded input data. In particular, this shows that the strip packing problem admits no quasi-polynomial time...

  4. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... drugs is hard because addiction is a brain disease. Your brain is like a control tower that ... views 5:42 Wait21 -- Understanding Addiction as a Disease - Duration: 3:41. TheNABCA 17,946 views 3: ...

  5. Registration of 'Sunshine' Hard White Winter Wheat

    Science.gov (United States)

    ’Sunshine’ (Reg. No. CV-XXXX, PI 674741) hard white winter wheat (Triticum aestivum L.) was developed by the Colorado Agricultural Experiment Station and released in August 2014 through a marketing agreement with the Colorado Wheat Research Foundation. In addition to researchers at Colorado State Un...

  6. Registration of 'Prevail' hard red spring wheat

    Science.gov (United States)

    Grower and end-user acceptance of new Hard Red Spring Wheat (HRSW; Triticum aestivum L.) cultivars is largely contingent upon satisfactory agronomic performance, end-use quality potential, and disease resistance levels. Additional characteristics, such as desirable plant height, can also contribute...

  7. "Work smart, wear your hard hat"

    CERN Multimedia

    2003-01-01

    Falling objects and collisions are frequent occurrences in work sites and hazardous areas. Hard hats can help prevent many types of accident and can even save lives. Just imagine an 800 g spanner falling from a 13 m high scaffold onto the head of someone standing below - a nightmare scenario! The impact to the head is equivalent to that of a 5 kg weight falling from 2 metres. That is just what happened to Gerd Fetchenhauer when he was working on the UA1 experiment. Fortunately, he was wearing a hard hat at the time. "That hat saved my life," he explains. "It punched a hole right through the hat and I was a bit dazed for a couple of hours but otherwise I was OK." Since that day, Gerd Fetchenhauer, now working on CMS, is never seen on a work site without his hard hat on. Work sites have proliferated at CERN with the construction of the LHC and its detectors, and the wearing of hard hats is compulsory (not to mention life-saving). In the underground caverns and experiment halls, where gantry cranes and other h...

  8. Thermalizing nuclear matter probed by hard photons

    NARCIS (Netherlands)

    Schutz, Y

    1998-01-01

    The hard photon spectrum emitted in heavy-ion collisions is analyzed in the light of dynamical phase-space considerations to infer information on the thermodynamical properties of hot and dense nuclear matter. Energy spectrum, angular distribution and two-photon interference pattern converge to

  9. Second virial coefficients of dipolar hard spheres

    NARCIS (Netherlands)

    Philipse, A.P.; Kuipers, B.W.M.

    2010-01-01

    An asymptotic formula is reported for the second virial coefficient B2 of a dipolar hard-sphere (DHS) fluid, in zero external field, for strongly coupled dipolar interactions. This simple formula, together with the one for the weak-coupling B2, provides an accurate prediction of the second virial

  10. Parallel Narrative Structure in Paul Harding's "Tinkers"

    Science.gov (United States)

    Çirakli, Mustafa Zeki

    2014-01-01

    The present paper explores the implications of parallel narrative structure in Paul Harding's "Tinkers" (2009). Besides primarily recounting the two sets of parallel narratives, "Tinkers" also comprises of seemingly unrelated fragments such as excerpts from clock repair manuals and diaries. The main stories, however, told…

  11. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... drugs is hard because addiction is a brain disease. Your brain is like a control tower that ... views 6:13 Wait21 -- Understanding Addiction as a Disease - Duration: 3:41. TheNABCA 17,728 views 3: ...

  12. Locating phase transitions in computationally hard problems

    Indian Academy of Sciences (India)

    Treating the computational time, value and utility functions involved in the search results in analogy with quantities in statistical physics, we indicate how the onset of a computationally hard regime can be detected and the transit to higher quality solutions be quantified by an appropriate response function. The existence of a ...

  13. The phase behavior of linear and partially flexible hard-sphere chain fluids and the solubility of hard spheres in hard-sphere chain fluids

    NARCIS (Netherlands)

    Oyarzun, B.A.; Van Westen, T.; Vlugt, T.J.H.

    2013-01-01

    he liquid crystal phase behavior of linear and partially flexible hard-sphere chain fluids and the solubility of hard spheres in hard-sphere chain fluids are studied by constant pressure Monte Carlo simulations. An extensive study on the phase behavior of linear fluids with a length of 7, 8, 9, 10,

  14. Microbiological quality of soft, semi-hard and hard cheeses during the shelf-life

    Directory of Open Access Journals (Sweden)

    Josip Vrdoljak

    2016-03-01

    Full Text Available Cheeses as ready-to-eat food should be considered as a potential source of foodborne pathogens, primarily Listeria monocytogenes. The aim of present study was to determine the microbiological quality of soft, semi-hard and hard cheeses during the shelf-life, with particular reference to L. monocytogenes. Five types of cheeses were sampled at different timepoints during the cold storage and analyzed for presence of Salmonella and L. monocytogenes, as well as lactic acid bacteria, Escherichia coli, coagulase-positive staphylococci, yeasts, molds, sulfite-reducing clostridia and L. monocytogenes counts. Water activity, pH and NaCl content were monitored in order to evaluate the possibility of L. monocytogenes growth. Challenge test for L. monocytogenes was performed in soft whey cheese, to determine the growth potential of pathogen during the shelf-life of product. All analyzed cheeses were compliant with microbiological criteria during the shelf-life. In soft cheeses, lactic acid bacteria increased in the course of the shelf-life period (1.2-2.6 log increase, while in semi-hard and hard cheeses it decreased (1.6 and 5.2 log decrease, respectively. Soft cheeses support the growth of L. monocytogenes according to determined pH values (5.8-6.5, water activity (0.99-0.94, and NaCl content (0.3-1.2%. Challenge test showed that L. monocytogenes growth potential in selected soft cheese was 0.43 log10 cfu/g during 8 days at 4°C. Water activity in semi-hard and hard cheeses was a limiting factor for Listeria growth during the shelf-life. Soft, semi-hard and hard cheeses were microbiologically stable during their defined shelf-life. Good manufacturing and hygienic practices must be strictly followed in the production of soft cheeses as Listeria-supporting food and be focused on preventing (recontamination.

  15. Further links between the maximum hardness principle and the hard/soft acid/base principle: insights from hard/soft exchange reactions.

    Science.gov (United States)

    Chattaraj, Pratim K; Ayers, Paul W; Melin, Junia

    2007-08-07

    Ayers, Parr, and Pearson recently showed that insight into the hard/soft acid/base (HSAB) principle could be obtained by analyzing the energy of reactions in hard/soft exchange reactions, i.e., reactions in which a soft acid replaces a hard acid or a soft base replaces a hard base [J. Chem. Phys., 2006, 124, 194107]. We show, in accord with the maximum hardness principle, that the hardness increases for favorable hard/soft exchange reactions and decreases when the HSAB principle indicates that hard/soft exchange reactions are unfavorable. This extends the previous work of the authors, which treated only the "double hard/soft exchange" reaction [P. K. Chattaraj and P. W. Ayers, J. Chem. Phys., 2005, 123, 086101]. We also discuss two different approaches to computing the hardness of molecules from the hardness of the composing fragments, and explain how the results differ. In the present context, it seems that the arithmetic mean of fragment softnesses is the preferable definition.

  16. Is hyper-hardness more chemically relevant than expected?

    Science.gov (United States)

    Morell, Christophe; Grand, André; Toro-Labbé, Alejandro; Chermette, Henry

    2013-07-01

    In this work, the third derivative of the energy with respect to the number of electrons, the so-called hyper-hardness, is investigated to assess whether this quantity has a chemical meaning. To achieve this goal a new working expression for hyper-hardness is developed and analyzed. It transpired from this analysis that hyper-hardness, just like hardness, can measure the reactivity or the stability of electron systems. Interestingly, positive values of hyper-hardness point to quite stable species such as noble gases and molecules. On the other hand, radicals almost always display large negative values of hyper-hardness.

  17. Hard-on-hard lubrication in the artificial hip under dynamic loading conditions.

    Directory of Open Access Journals (Sweden)

    Robert Sonntag

    Full Text Available 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.

  18. Developing very hard nanostructured bainitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Amel-Farzad, H., E-mail: hh_amel@yahoo.com [Department of Materials Engineering and Metallurgy, Faculty of Engineering, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of); Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Faridi, H.R., E-mail: faridihr@yahoo.com [Department of Materials Engineering and Metallurgy, Hamedan University of Technology, Hamedan (Iran, Islamic Republic of); Rajabpour, F.; Abolhasani, A.; Kazemi, Sh.; Khaledzadeh, Y. [Department of Materials Engineering and Metallurgy, Faculty of Engineering, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of)

    2013-01-01

    Novel nanostructured high carbon high silicon, carbide-free bainitic steels with very high strength and good ductility have been developed in the recent decade. In this work, an alloy with a high carbon content and no manganese was designed and cast. The prepared samples were heat treated through an austempering process in the range 200-350 Degree-Sign C. Optical and scanning electron microscopes and XRD were used to analyze the microstructures precisely. Bainitic ferrite plates of just a few tens of nanometer thickness were obtained with the hardness of 697{+-}6 HV. It is reasonable to say that the unprecedented hardness values obtained in this work are mostly caused by the extraordinary carbon content of the alloy.

  19. Hardness/intensity correlations among BATSE bursts

    Science.gov (United States)

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

    1992-01-01

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

  20. Hard exclusive reactions and generalized parton distributions

    Directory of Open Access Journals (Sweden)

    Hayrapetyan Avetik

    2015-01-01

    Full Text Available The recently developed formalism of Generalized Parton Distributions (GPDs allows connecting the experimental information of hard exclusive reactions to the spin contribution and even to the angular momentum contribution of quarks in the nucleon. By selecting different quantum numbers of the final state in exclusive productions, different GPDs can be addressed separately. The HERMES experiment at the HERA ring at DESY (Hamburg made pioneering contributions and first constraints to Generalized Parton Distributions (GPDs, using hard exclusive vector meson production (EVMP and Deeply Virtual Compton Scattering (DVCS. Using a novel recoil detector, HERMES managed to measure DVCS and EVMP free of any significant background. Selected results are highlighted and discussed in this paper.