WorldWideScience

Sample records for nanoindentation specimen holder

  1. Specimen Holder For Flammability Tests

    Science.gov (United States)

    Rucker, Michelle A.

    1992-01-01

    Fixture holds sheet specimens for flammability tests. Frame and clamps designed to minimize local overstress on specimen. Heat capacity of fixture low, interfering less with interpretation of results of test by drawing less heat away from specimen. Accepts films, fabrics, foams, and other sheets, rigid or flexible. Specimens thin or thick, or of variable thickness. Bent to accommodate curved rigid specimens. Also used for such other tests as particle-impact tests.

  2. 16 CFR Figure 3 to Part 1610 - Specimen Holder Supported in Specimen Rack

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Specimen Holder Supported in Specimen Rack 3 Figure 3 to Part 1610 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FLAMMABLE FABRICS ACT... Holder Supported in Specimen Rack ER25MR08.002...

  3. Mode-II-Fracture Specimen And Holder

    Science.gov (United States)

    Buzzard, Robert J.; Ghosn, Louis; Succop, George

    1991-01-01

    Test specimen and loading frame developed for fatigue and fracture testing of materials under mode-II (sliding-mode) loading. Assembly placed in compression-testing machine. Loads directed oppositely along centerline cause self-similar crack to propagate. Enables consistently accurate alignment of specimens before insertion of specimen/frame assemblies into compression-testing machine. Makes design attractive for testing in hostile environments in which access to machine or furnace limited. Additional feature, with little or no modification, placed horizontally into impact testing machine and subjected to loading at high speeds.

  4. A cylindrical specimen holder for electron cryo-tomography

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, Colin M., E-mail: cpalmer@mrc-lmb.cam.ac.uk; Löwe, Jan, E-mail: jyl@mrc-lmb.cam.ac.uk

    2014-02-01

    The use of slab-like flat specimens for electron cryo-tomography restricts the range of viewing angles that can be used. This leads to the “missing wedge” problem, which causes artefacts and anisotropic resolution in reconstructed tomograms. Cylindrical specimens provide a way to eliminate the problem, since they allow imaging from a full range of viewing angles around the tilt axis. Such specimens have been used before for tomography of radiation-insensitive samples at room temperature, but never for frozen-hydrated specimens. Here, we demonstrate the use of thin-walled carbon tubes as specimen holders, allowing the preparation of cylindrical frozen-hydrated samples of ribosomes, liposomes and whole bacterial cells. Images acquired from these cylinders have equal quality at all viewing angles, and the accessible tilt range is restricted only by the physical limits of the microscope. Tomographic reconstructions of these specimens demonstrate that the effects of the missing wedge are substantially reduced, and could be completely eliminated if a full tilt range was used. The overall quality of these tomograms is still lower than that obtained by existing methods, but improvements are likely in future. - Highlights: • The missing wedge is a serious problem for electron cryo-tomography. • Cylindrical specimens allow the missing wedge to be eliminated. • Carbon nanopipettes can be used as cylindrical holders for tomography of frozen-hydrated specimens. • Cryo-tomography of cylindrical biological samples demonstrates a reduction of deleterious effects associated with the missing wedge.

  5. 16 CFR Figure 6 to Subpart A of... - Dummy Specimen in Specimen Holder

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Dummy Specimen in Specimen Holder 6 Figure 6 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS INTERIM SAFETY STANDARD FOR CELLULOSE INSULATION The Standard Pt. 1209, Subpt. A...

  6. Multifunctional TEM-specimen holder equipped with a piezodriving probe and an electron irradiation port.

    Science.gov (United States)

    Shindo, Daisuke; Suzuki, Satoshi; Sato, Kuniaki; Akase, Zentaro; Murakami, Yasukazu; Yamazaki, Kazuya; Ikeda, Yuuta; Fukuda, Tomohisa

    2013-08-01

    The charging effect due to electron irradiation in an electron microscope has been studied so far with incident electrons. Here we report on a new specimen holder to control the charging effect by using electrons emitted from an irradiation port in the holder while maintaining a constant intensity of the incident electron beam. Details of the charging effect, such as electric field variation, are expected to be investigated by electron holography. The new specimen holder was developed by modifying a double-probe piezodriving specimen holder to introduce an electron irradiation port in one of its two arms. As a result, the new modified specimen holder consists of a piezodriving probe and an electron irradiation port, both of which can be controlled in three dimensions, using piezoelectric elements and micrometers. We demonstrate that variations in the charging effect for epoxy resin and surface contamination can be observed by electron holography.

  7. A combined environmental straining specimen holder for high-voltage electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Yoshimasa, E-mail: yoshim.takahashi@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Tanaka, Masaki; Higashida, Kenji [Department of Materials Science and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Yasuda, Kazuhiro; Matsumura, Syo [Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Noguchi, Hiroshi [Department of Mechanical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2010-10-15

    A novel specimen holder that enables in situ observation of crack-tip deformation and/or fracture under a controlled environment is developed for a high-voltage electron microscope (HVEM). A window-type environmental cell (EC) that incorporates a uniaxial straining apparatus is built into a side-entry-type single-tilt specimen holder. The gas control in EC, straining apparatus design, limited field of view for crack-tip observation, and specimen preparation for the specimen holder are presented in detail. Experimental results successfully demonstrate that the developed specimen holder is quite useful for the dynamic observation of crack-tip deformation and/or fracture subjected to a hostile environment, such as hydrogen gas.

  8. Low specimen drift holder, cooler and heat flow reductor for use in microscopy

    NARCIS (Netherlands)

    Zandbergen, H.W.

    2015-01-01

    The present invention is in the field of a low specimen drift holder and cooler for use in microscopy, and a microscope comprising said holder. The present invention is in the field of microscopy, specifically in the field of electron and focused ion beam mi- croscopy (EM and FIB). However it applic

  9. A simple cryo-holder facilitates specimen observation under a conventional scanning electron microscope.

    Science.gov (United States)

    Tang, Chih-Yuan; Huang, Rong-Nan; Kuo-Huang, Ling-Long; Kuo, Tai-Chih; Yang, Ya-Yun; Lin, Ching-Yeh; Jane, Wann-Neng; Chen, Shiang-Jiuun

    2012-02-01

    A pre-cryogenic holder (cryo-holder) facilitating cryo-specimen observation under a conventional scanning electron microscope (SEM) is described. This cryo-holder includes a specimen-holding unit (the stub) and a cryogenic energy-storing unit (a composite of three cylinders assembled with a screw). After cooling, the cryo-holder can continue supplying cryogenic energy to extend the observation time for the specimen in a conventional SEM. Moreover, the cryogenic energy-storing unit could retain appropriate liquid nitrogen that can evaporate to prevent frost deposition on the surface of the specimen. This device is proved feasible for various tissues and cells, and can be applied to the fields of both biology and material science. We have employed this novel cryo-holder for observation of yeast cells, trichome, and epidermal cells in the leaf of Arabidopsis thaliana, compound eyes of insects, red blood cells, filiform papillae on the surface of rat tongue, agar medium, water molecules, penicillium, etc. All results suggested that the newly designed cryo-holder is applicable for cryo-specimen observation under a conventional SEM without cooling system. Most importantly, the design of this cryo-holder is simple and easy to operate and could adapt a conventional SEM to a plain type cryo-SEM affordable for most laboratories.

  10. Specimen holder for an electron microscope, and method for reducing thermal drift in a microscope

    NARCIS (Netherlands)

    Zandbergen, H.W.

    2004-01-01

    A specimen holder for an electron microscope, comprising a rod-shaped part, which is provided near one end with a tip, which tip is arranged to receive a specimen, the rod-shaped part, in use, extending with at least the tip into the electron microscope, held by clamping means present in the electro

  11. Development of a versatile TEM specimen holder for the characterization of photocatalytic materials

    DEFF Research Database (Denmark)

    Cavalca, Filippo; Langhammer, C.; Hansen, Thomas Willum

    2011-01-01

    electrical, pressure and temperature measurements as well as to power custom MEMS-based in situ heaters. It can be used inside an ETEM allowing specimens to be analysed in a controlled gas atmosphere during biasing and illuminating experiments. A second, more advanced version of the holder has also been....../on nanomaterials and thin films. We present results from combined ETEM-LSPR studies of thermally-induced catalytic phenomena and on metal nanoparticle sintering, an important process in catalysis, which we study in situ in both real and model systems by means of indirect nanoplasmonic sensing and ETEM....

  12. Specimen Size Effects on Zr-Based Bulk Metallic Glasses Investigated by Uniaxial Compression and Spherical Nanoindentation

    Science.gov (United States)

    Bei, H.; Lu, Z. P.; Shim, S.; Chen, G.; George, E. P.

    2010-07-01

    Specimen size effects on the mechanical behavior of Zr-based bulk metallic glasses (BMGs) were investigated by compression and nanoindentation tests. In compression, even at the 1- to 10-mm scale, stable shear band propagation and extensive plastic deformation can be achieved in small (2 mm) specimens, in contrast to large (6.5 mm) specimens, which fail catastrophically after limited plastic deformation. The yield strength is independent of specimen size in this range, and plastic deformation remains highly localized in a few shear bands even in those specimens that exhibit stable shear sliding. The fracture surfaces of small specimens are smooth, without the vein patterns normally observed as characteristic features on the fracture surfaces of BMGs. During spherical nanoindentation, it is found that the upper bound of the maximum shear stress to initiate plasticity (yielding) in a Zr-based BMG is almost constant for indenter radii smaller than ~90 µm. However, the lower bound of this maximum shear stress decreases with increasing indenter radius, probably due to the increased probability of finding defects underneath larger indenters.

  13. High-angle triple-axis specimen holder for three-dimensional diffraction contrast imaging in transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hata, S., E-mail: hata.satoshi.207@m.kyushu-u.ac.jp [Department of Electrical and Materials Science, Kyushu University, Kasuga, 6-1 Kasugakoen, Kasuga, Fukuoka 816-8580 (Japan); Miyazaki, H. [Mel-Build, Nishi-ku, Fukuoka 819-0052 (Japan); Miyazaki, S. [FEI Company Japan Ltd., Minato-ku, Tokyo 108-0075 (Japan); Mitsuhara, M. [Department of Electrical and Materials Science, Kyushu University, Kasuga, 6-1 Kasugakoen, Kasuga, Fukuoka 816-8580 (Japan); Tanaka, M.; Kaneko, K.; Higashida, K. [Department of Materials Science and Engineering, Kyushu University, Nishi-ku, Fukuoka 819-0395 (Japan); Ikeda, K.; Nakashima, H. [Department of Electrical and Materials Science, Kyushu University, Kasuga, 6-1 Kasugakoen, Kasuga, Fukuoka 816-8580 (Japan); Matsumura, S. [Department of Applied Physics and Nuclear Engineering, Kyushu University, Nishi-ku, Fukuoka 819-0395 (Japan); Barnard, J.S. [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); Sharp, J.H. [Department of Materials Science and Engineering, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD (United Kingdom); Midgley, P.A. [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom)

    2011-07-15

    Electron tomography requires a wide angular range of specimen-tilt for a reliable three-dimensional (3D) reconstruction. Although specimen holders are commercially available for tomography, they have several limitations, including tilting capability in only one or two axes at most, e.g. tilt-rotate. For amorphous specimens, the image contrast depends on mass and thickness only and the single-tilt holder is adequate for most tomographic image acquisitions. On the other hand, for crystalline materials where image contrast is strongly dependent on diffraction conditions, current commercially available tomography holders are inadequate, because they lack tilt capability in all three orthogonal axes needed to maintain a constant diffraction condition over the whole tilt range. We have developed a high-angle triple-axis (HATA) tomography specimen holder capable of high-angle tilting for the primary horizontal axis with tilting capability in the other (orthogonal) horizontal and vertical axes. This allows the user to trim the specimen tilt to obtain the desired diffraction condition over the whole tilt range of the tomography series. To demonstrate its capabilities, we have used this triple-axis tomography holder with a dual-axis tilt series (the specimen was rotated by 90{sup o} ex-situ between series) to obtain tomographic reconstructions of dislocation arrangements in plastically deformed austenitic steel foils. -- Highlights: {yields} A double tilt-rotate specimen holder for diffraction contrast imaging in electron tomography. {yields} Precise alignment of a diffraction condition for tilt-series acquisition of TEM/STEM images. {yields} Complete visualization of 3D dislocation arrangements by dual-axis STEM tomography.

  14. Electrical and Thermal View Points for Designing Conduction-Cooled Specimen Holder for Short Sample Testing

    Science.gov (United States)

    Järvelä, J.; Stenvall, A.; Mikkonen, R.

    Theelectrical and stabilitypropertiesof superconductivestrandsareoftencharacterizedby short sample testing.These tests are often done in a measurement system where the sample is cooled by liquid cryogen or cold gas flow. In both approaches, the sample temperature during a measurement is stabilized by the abundance of available cooling power. This also helps to protect the sample during a thermal runaway i.e. quench. However, in some characterizations, e.g. minimum quench energy testing, the cooling conditions can have a significant effect on the results. Therefore a more adiabatic solution is prefer able as iten able seasier comparison of the results from different measurement stations. One solution to achieving the desired adiabacy is to use conduction-cooling and vacuum insulation. As there is no cooling fluidtorelyon, as cheme for sample protection has to be implemented. Inaconduction-cooled setup, one way to protect the sampleis to use an active protection system in conjunction with aproperly designed sample holder. In this publication, we present an electrical and thermal analysis of a conduction-cooled sample holder suitable for both critical current and minimum quench energy measurements. A coupled electro-thermal finite element method model was constructed to study the sample holder performance during measurement. For our application, the performance is defined by the ohmic losses in the holder component sand by the recovery time from as amplequench.

  15. A novel and compact nanoindentation device for in situ nanoindentation tests inside the scanning electron microscope

    Directory of Open Access Journals (Sweden)

    Hu Huang

    2012-03-01

    Full Text Available In situ nanomechanical tests provide a unique insight into mechanical behaviors of materials, such as fracture onset and crack propagation, shear band formation and so on. This paper presents a novel in situ nanoindentation device with dimensions of 103mm×74mm×60mm. Integrating the stepper motor, the piezoelectric actuator and the flexure hinge, the device can realize coarse adjustment of the specimen and precision loading and unloading of the indenter automatically. A novel indenter holder was designed to guarantee that the indenter penetrates into and withdraws from the specimen surface vertically. Closed-loop control of the indentation process was established to solve the problem of nonlinearity of the piezoelectric actuator and to enrich the loading modes. The in situ indentation test of Indium Phosphide (InP inside the scanning electron microscope (SEM was carried out and the experimental result indicates the feasibility of the developed device.

  16. Tomographic Heating Holder for In Situ TEM

    DEFF Research Database (Denmark)

    Gontard, Lionel C.; Dunin-Borkowski, Rafal E.; Fernández, Asunción

    2014-01-01

    A tomographic heating holder for transmission electron microscopy that can be used to study supported catalysts at temperatures of up to ~1,500°C is described. The specimen is placed in direct thermal contact with a tungsten filament that is oriented perpendicular to the axis of the holder withou...

  17. Atomistic simulations of nanoindentation

    Directory of Open Access Journals (Sweden)

    Izabela Szlufarska

    2006-05-01

    Full Text Available Our understanding of mechanics is pushed to its limit when the functionality of devices is controlled at the nanometer scale. A fundamental understanding of nanomechanics is needed to design materials with optimum properties. Atomistic simulations can bring an important insight into nanostructure-property relations and, when combined with experiments, they become a powerful tool to move nanomechanics from basic science to the application area. Nanoindentation is a well-established technique for studying mechanical response. We review recent advances in modeling (atomistic and beyond of nanoindentation and discuss how they have contributed to our current state of knowledge.

  18. Specimen loading list for the varying temperature experiment

    Energy Technology Data Exchange (ETDEWEB)

    Qualls, A.L.; Sitterson, R.G. [Oak Ridge National Lab., TN (United States)

    1998-09-01

    The varying temperature experiment HFIR-RB-13J has been assembled and inserted in the reactor. Approximately 5300 specimens were cleaned, inspected, matched, and loaded into four specimen holders. A listing of each specimen loaded into the steady temperature holder, its position in the capsule, and the identification of the corresponding specimen loaded into the varying temperature holder is presented in this report.

  19. A novel sample preparation method to avoid influence of embedding medium during nano-indentation

    Science.gov (United States)

    Yujie Meng; Siqun Wang; Zhiyong Cai; Timothy M. Young; Guanben Du; Yanjun Li

    2012-01-01

    The effect of the embedding medium on the nano-indentation measurements of lignocellulosic materials was investigated experimentally using nano-indentation. Both the reduced elastic modulus and the hardness of nonembedded cell walls were found to be lower than those of the embedded samples, proving that the embedding medium used for specimen preparation on cellulosic...

  20. Modeling and Simulation of Nanoindentation

    Science.gov (United States)

    Huang, Sixie; Zhou, Caizhi

    2017-08-01

    Nanoindentation is a hardness test method applied to small volumes of material which can provide some unique effects and spark many related research activities. To fully understand the phenomena observed during nanoindentation tests, modeling and simulation methods have been developed to predict the mechanical response of materials during nanoindentation. However, challenges remain with those computational approaches, because of their length scale, predictive capability, and accuracy. This article reviews recent progress and challenges for modeling and simulation of nanoindentation, including an overview of molecular dynamics, the quasicontinuum method, discrete dislocation dynamics, and the crystal plasticity finite element method, and discusses how to integrate multiscale modeling approaches seamlessly with experimental studies to understand the length-scale effects and microstructure evolution during nanoindentation tests, creating a unique opportunity to establish new calibration procedures for the nanoindentation technique.

  1. Flame Holder System

    Science.gov (United States)

    Haskin, Henry H. (Inventor); Vasquez, Peter (Inventor)

    2013-01-01

    A flame holder system includes a modified torch body and a ceramic flame holder. Catch pin(s) are coupled to and extend radially out from the torch body. The ceramic flame holder has groove(s) formed in its inner wall that correspond in number and positioning to the catch pin(s). Each groove starts at one end of the flame holder and can be shaped to define at least two 90.degree.turns. Each groove is sized to receive one catch pin therein when the flame holder is fitted over the end of the torch body. The flame holder is then manipulated until the catch pin(s) butt up against the end of the groove(s).

  2. ADJUSTABLE CHIP HOLDER

    DEFF Research Database (Denmark)

    2009-01-01

    An adjustable microchip holder for holding a microchip is provided having a plurality of displaceable interconnection pads for connecting the connection holes of a microchip with one or more external devices or equipment. The adjustable microchip holder can fit different sizes of microchips with ...

  3. Nanoindentation of biological composites

    Science.gov (United States)

    Dickinson, M.

    2009-08-01

    This investigation studied the effect of storage conditions on the mechanical properties as measured by nanoindentation of mineralised tissue samples. The three storage solutions were Hanks balanced salt solution, phosphate buffered saline and deionised water and all had a significant effect on the surface properties, namely hardness and modulus of enamel, dentin and bone tested. The effect was significant with a greater than 70% reduction in surface mechanical properties after 8 days immersion in the solutions. This study highlights the importance of testing biological tissues immediately after extraction, and the possible structural and chemistry changes that may occur by artificially storing the tissues.

  4. Development of a novel straining holder for transmission electron microscopy compatible with single tilt-axis electron tomography.

    Science.gov (United States)

    Sato, K; Miyazaki, H; Gondo, T; Miyazaki, S; Murayama, M; Hata, S

    2015-10-01

    We have developed a newly designed straining specimen holder for in situ transmission electron microscopy (TEM) compatible with high-angle single tilt-axis electron tomography. The holder can deform a TEM specimen under tensile stress with the strain rate between 1.5 × 10(-6) and 5.2 × 10(-3) s(-1). We have also confirmed that the maximum tilt angle of the specimen holder reaches ±60° with a rectangular shape aluminum specimen. The new specimen holder, termed as 'straining and tomography holder', will have wide range potential applications in materials science.

  5. [Phantom holder of CT couch].

    Science.gov (United States)

    Zhang, Ruixia; Zhan, Hongyu; Wang, Di

    2014-03-01

    This article describes a phantom holder in CT couch which adjusted easily and accurately, installed easily. The holder mainly include removing and locking equipment between phantom holder and table top, move horizontally equipment between left and right, rotating equipment between left and right. After holder and table top fixed one part, holder with phantom can move horizontally, front and back, rotate between left and right in a small angle, in order to make operator test phantoms accurately and easily. At the same time, this phantom holder realized free adjustment after first adjustments, which shortened operator work time.

  6. Improvement of effective solid angle using virtual-pivot holder and large EDS detector.

    Science.gov (United States)

    Koshiya, Shogo; Kimoto, Koji

    2017-02-01

    This paper describes the effective solid angle improvement achieved using a large-area silicon drift detector together with a virtual-pivot double-tilt specimen holder. The virtual-pivot mechanism enables various designs of specimen-retaining and can reduce the shadowing effect. Energy-dispersive X-ray spectra were measured and converted into effective solid angles using different types of specimen holders and specimens. The investigated shadowing-free mechanical system yielded effective solid angles approaching the nominal solid angle of 0.464sr. In addition, we have demonstrated the availability of the plastic (polyetheretherketone) specimen holder for low system noise.

  7. Double acting bit holder

    Science.gov (United States)

    Morrell, Roger J.; Larson, David A.; Ruzzi, Peter L.

    1994-01-01

    A double acting bit holder that permits bits held in it to be resharpened during cutting action to increase energy efficiency by reducing the amount of small chips produced. The holder consist of: a stationary base portion capable of being fixed to a cutter head of an excavation machine and having an integral extension therefrom with a bore hole therethrough to accommodate a pin shaft; a movable portion coextensive with the base having a pin shaft integrally extending therefrom that is insertable in the bore hole of the base member to permit the moveable portion to rotate about the axis of the pin shaft; a recess in the movable portion of the holder to accommodate a shank of a bit; and a biased spring disposed in adjoining openings in the base and moveable portions of the holder to permit the moveable portion to pivot around the pin shaft during cutting action of a bit fixed in a turret to allow front, mid and back positions of the bit during cutting to lessen creation of small chip amounts and resharpen the bit during excavation use.

  8. Development of a precision nanoindentation platform

    Science.gov (United States)

    Nowakowski, B. K.; Smith, D. T.; Smith, S. T.; Correa, L. F.; Cook, R. F.

    2013-07-01

    The design, construction, and performance of a surface-referenced nanoindentation instrument, termed a precision nanoindentation platform (PNP), are presented. The PNP is a symmetrically designed instrument with a centrally located indenter tip attached to a force cell for measuring the forces between the tip and a specimen. Penetration of the indenter tip into the specimen surface is measured using two proximity sensors placed symmetrically about the indenter. Each proximity sensor is attached to a piezoelectric actuator that is servo controlled to maintain the sensor and the reference frame to which it is attached at a constant height relative to the specimen surface. As the indenter tip penetrates the specimen surface, the movement of the tip relative to the two surface reference frames is measured using capacitance gauges and the average of these displacements is used as a measure of penetration depth. The current indenter is capable of applying indentation forces of up to 150 mN with a noise floor below 2 μN rms for a sampling rate of 1 kHz, and measuring displacement with 0.4 nm rms noise for the same sampling rate. The proximity sensors are capable of maintaining surface height variations of less than 1.0 nm with penetration depths of up to 10 μm. Long-term stability tests indicate a total uncertainty in indentation depth less than 10 nm for periods as long as 12 h. To demonstrate instrument accuracy, repeated indention cycles were performed on a fused silica specimen using incrementally increasing indention force. From this test, an average value of 72 GPa ± 1.5 GPa for the Young's modulus was obtained from the elastic unloading curves for 10 measurements ranging in maximum force from 5 mN to 50 mN. To demonstrate longer-term instrument stability, a poly(methyl methacrylate) specimen was subjected to a fixed 5 mN indentation force for 4 h; two distinct creep-like mechanisms were observed.

  9. Development of a precision nanoindentation platform.

    Science.gov (United States)

    Nowakowski, B K; Smith, D T; Smith, S T; Correa, L F; Cook, R F

    2013-07-01

    The design, construction, and performance of a surface-referenced nanoindentation instrument, termed a precision nanoindentation platform (PNP), are presented. The PNP is a symmetrically designed instrument with a centrally located indenter tip attached to a force cell for measuring the forces between the tip and a specimen. Penetration of the indenter tip into the specimen surface is measured using two proximity sensors placed symmetrically about the indenter. Each proximity sensor is attached to a piezoelectric actuator that is servo controlled to maintain the sensor and the reference frame to which it is attached at a constant height relative to the specimen surface. As the indenter tip penetrates the specimen surface, the movement of the tip relative to the two surface reference frames is measured using capacitance gauges and the average of these displacements is used as a measure of penetration depth. The current indenter is capable of applying indentation forces of up to 150 mN with a noise floor below 2 μN rms for a sampling rate of 1 kHz, and measuring displacement with 0.4 nm rms noise for the same sampling rate. The proximity sensors are capable of maintaining surface height variations of less than 1.0 nm with penetration depths of up to 10 μm. Long-term stability tests indicate a total uncertainty in indentation depth less than 10 nm for periods as long as 12 h. To demonstrate instrument accuracy, repeated indention cycles were performed on a fused silica specimen using incrementally increasing indention force. From this test, an average value of 72 GPa ± 1.5 GPa for the Young's modulus was obtained from the elastic unloading curves for 10 measurements ranging in maximum force from 5 mN to 50 mN. To demonstrate longer-term instrument stability, a poly(methyl methacrylate) specimen was subjected to a fixed 5 mN indentation force for 4 h; two distinct creep-like mechanisms were observed.

  10. Jointed Holder For Welding Electrodes

    Science.gov (United States)

    Gilbert, Jeffrey L.

    1991-01-01

    Adjustable-angle holder enables use of standard straight electrode with custom-fabricated bent gas cup for welding in difficult-to-reach places. Electrode replaced easily, without removing cup, with aid of tool loosening miniature collet nut on holder. Consumes fewer electrodes for given amount of welding. Angle of holder continuously adjustable to fit angle of gas cup or geometry of part welded. Holder made double-jointed to accommodate gas cup having compound angles.

  11. Interfacial modulus mapping of layered dental ceramics using nanoindentation

    Science.gov (United States)

    Bushby, Andrew J; P'ng, Ken MY; Wilson, Rory M

    2016-01-01

    PURPOSE The aim of this study was to test the modulus of elasticity (E) across the interfaces of yttria stabilized zirconia (YTZP) / veneer multilayers using nanoindentation. MATERIALS AND METHODS YTZP core material (KaVo-Everest, Germany) specimens were either coated with a liner (IPS e.max ZirLiner, Ivoclar-Vivadent) (Type-1) or left as-sintered (Type-2) and subsequently veneered with a pressable glass-ceramic (IPS e.max ZirPress, Ivoclar-Vivadent). A 5 µm (nominal tip diameter) spherical indenter was used with a UMIS CSIRO 2000 (ASI, Canberra, Australia) nanoindenter system to test E across the exposed and polished interfaces of both specimen types. The multiple point load – partial unload method was used for E determination. All materials used were characterized using Scanning Electron Microscopy (SEM) and X – ray powder diffraction (XRD). E mappings of the areas tested were produced from the nanoindentation data. RESULTS A significantly (P<.05) lower E value between Type-1 and Type-2 specimens at a distance of 40 µm in the veneer material was associated with the liner. XRD and SEM characterization of the zirconia sample showed a fine grained bulk tetragonal phase. IPS e-max ZirPress and IPS e-max ZirLiner materials were characterized as amorphous. CONCLUSION The liner between the YTZP core and the heat pressed veneer may act as a weak link in this dental multilayer due to its significantly (P<.05) lower E. The present study has shown nanoindentation using spherical indentation and the multiple point load - partial unload method to be reliable predictors of E and useful evaluation tools for layered dental ceramic interfaces. PMID:28018566

  12. Determination of the mechanical behavior of lithium disilicate glass ceramics by nanoindentation and scanning probe microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Calvin M. [Matter and Materials, College of Science, Technology and Engineering, James Cook University, James Cook Drive, Townsville, QLD 4811 (Australia); Jiang, Danyu [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Gong, Jianghong [Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Yin, Ling, E-mail: ling.yin@jcu.edu.au [Matter and Materials, College of Science, Technology and Engineering, James Cook University, James Cook Drive, Townsville, QLD 4811 (Australia)

    2014-12-15

    This paper reports on the mechanical behavior of high-strength dental ceramics, lithium disilicate glass ceramics (LDGC) using nanoindentation and in situ scanning probe microscopy (SPM). The nanoindentation hardness and Young's moduli of LDGC were measured as a function of the applied indentation load. The indentation load/size effect (ISE) was analyzed for both measured nanoindentation hardness and Young's moduli. The true hardness, i.e., the load-independent hardness, was determined based on the proportional specimen resistance (PSR) model. Nanoindentation-induced plasticity in LDGC was characterized by in situ SPM imaging of the indented volumes and by measuring pile-up heights of indented cross-sections. The results show that both nanoindentation hardness and Young's modulus are load-dependent following the expended Meyer's law using a power series. At the nanoindentation loads, indented LDGC can be mainly plastically deformed by limiting cracking events. This unusual behavior, for nominally brittle materials, influences the mode of contact damage in applications such as machining, polishing, wear, impact damage and hardness testing for dental restorations. - Highlights: • Both hardness and Young's modulus of LDGC were load-dependent following the expended Meyer's law. • The true hardness of LDGC was determined based on the proportional specimen resistance (PSR) model. • Nanoindentation-induced plasticity in LDGC was characterized by in situ SPM imaging. • At low nanoindentation loads, indented LDGC can be mainly plastically deformed by limiting cracking events.

  13. Sample holder with optical features

    Science.gov (United States)

    Milas, Mirko; Zhu, Yimei; Rameau, Jonathan David

    2013-07-30

    A sample holder for holding a sample to be observed for research purposes, particularly in a transmission electron microscope (TEM), generally includes an external alignment part for directing a light beam in a predetermined beam direction, a sample holder body in optical communication with the external alignment part and a sample support member disposed at a distal end of the sample holder body opposite the external alignment part for holding a sample to be analyzed. The sample holder body defines an internal conduit for the light beam and the sample support member includes a light beam positioner for directing the light beam between the sample holder body and the sample held by the sample support member.

  14. Nanoindentation as a composition microprobe for nanolayer composites

    Energy Technology Data Exchange (ETDEWEB)

    Tambwe, M.F.; Stone, D.S. [Univ. of Wisconsin, Madison, WI (United States); Hirvonen, J.P.; Hannula, S.P. [VTT Manufacturing Technology, Espoo (Finland); Suni, I. [VTT Electronics, Espoo (Finland)

    1997-11-01

    Aluminum and tungsten differ by a factor of about 6 in Young`s modulus. For this reason, modulus measurements made by nanoindentation are sensitive to small variations in the relative amounts of aluminum and tungsten that make up the laminate composites. The volume fractions of the layers estimated based on the elasticity model for indentation of a transversely isotropic film on substrate agree well with the compositions measured by Rutherford Backscattering (RBS) except for the 3 nm (nominal) specimen, which, the authors have reason to believe based on x-ray diffraction measurements, contains intermetallic compounds.

  15. Probing the mechanical properties of dental porcelain through nanoindentation

    Science.gov (United States)

    Manda, Marianthi; Moschakis, Nikolaos; Konstantinidis, Avraam; Christophilos, Demetrios; Papadopoulou, Lambrini; Koidis, Petros; Aifantis, Elias

    2012-11-01

    The purpose of this short communication is to report on some micro/nanoscale aspects of the mechanical behavior of dental porcelain. Specimens were characterized by micro-Raman spectroscopy and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). Massive nanoindentation experiments on the surface of the specimens were performed, and typical load-displacement or load-depth (P-h) curves were obtained, which in turn were used to determine the Young modulus (E) and nanoindentation hardness (n-H), based on the Oliver-Pharr method [1]. Statistical analyses were carried out to determine the Spearman’s rank correlation coefficient (Spearman’s ρ), along with non-parametric linear regression analysis by employing Kolmogorov-Smirnov and Two-Step Cluster tests. Densification due to grain boundary diffusion and open-pore elimination was revealed by SEM. EDS analysis indicated a leucite-dispersed silicate glass matrix, as well as its contamination by traces of other minerals. Raman spectroscopy supported the EDS assignments. The P-h curves suggested that inelastic deformation and material flow increases at larger depths. Spearman’s ρ value showed strong dependence of E and n-H on h, indicating the occurrence of a size effect. The logarithmic data of E and n-H as functions of h were fitted by using linear regression analysis. The data did not obey a normal distribution (as the Kolmogorov-Smirnov test showed) due to the chemical heterogeneity involved. The Two-Step Cluster analysis indicated clustering in four groups associated with the chemical heterogeneity of the surface. Similar works using nanoindentation to determine the mechanical properties of dental materials can be found, for example, in [2, 3]. Corresponding methods for extracting the values of E and n-H from P-h experimental curves can be found, for example, in [4-6].

  16. The Applications of Modern Nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Van Buskirk, Caleb Griffith [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-16

    The TI-950 TriboIndenter is a nanoindentation device that obtains nanometer resolution material topography images using Scanning Probe Microscopy (SPM), modulus maps of material using nano-Dynamic Mechanical Analysis, and provides hardness measurements with a resolution of 0.2 nm. The instrument applies a force to a material through a sharp tip and used a transducer to measure the force a material applies back to the tip to derive information about the material. The information can be used to study the homogeneity of material surfaces as well as the homogeneity of the material as a function of depth and can lead to important information on the aging of the material as well as the consistency of the production of the material.

  17. In situ nanoindentation in a transmission electron microscope

    Science.gov (United States)

    Minor, Andrew Murphy

    This dissertation presents the development of the novel mechanical testing technique of in situ nanoindentation in a transmission electron microscope (TEM). This technique makes it possible to simultaneously observe and quantify the mechanical behavior of nano-scale volumes of solids. Chapter 2 details the unique specimen preparation techniques employed to meet the geometrical constraints of the in situ experiments. These techniques include bulk silicon micromachining and the use of a focused ion beam. In section 2.4 a method of voltage-controlled mechanical testing is derived theoretically and proven experimentally. This method enables the quantification of the mechanical behavior during in situ nanoindentation experiments. Three classes of material systems were studied with this new technique: (1) bulk single crystal, (2) a soft thin film on a harder substrate and (3) a hard thin film on a softer substrate. Section 3.2 provides the first direct evidence of dislocation nucleation in single crystal silicon at room temperature. In contrast to the observation of phase transformations during conventional indentation experiments, the unique geometry employed for the in situ experiments resulted in dislocation plasticity. In section 3.3 results from in situ nanoindentation of Al films on Si substrates are presented. These results include the correlation of the microstructural deformation behavior with load vs. displacement data. It is shown that a sharp change in the force-displacement response at the elastic-to-plastic transition signifies the nucleation of dislocations. Additionally, the softening of sub-micron grains with size is observed. Section 3.4 discussed the influence of the substrate on the indentation response of two thin film/substrate systems where the films were harder than the substrate. Amorphous diamond on Si and epitaxial TiN on MgO (001) systems were studied. It was found that the deformation in the harder films was controlled by the deformation in

  18. A versatile sample holder for single plane illumination microscopy.

    Science.gov (United States)

    Desmaison, Annaïck; Lorenzo, Corinne; Rouquette, Jacques; Ducommun, Bernard; Lobjois, Valérie

    2013-08-01

    Single Plane Illumination Microscopy is an emerging and powerful technology for live imaging of whole living organisms. However, sample handling that relies on specimen embedding in agarose or gel is often a key limitation, especially for time-lapse monitoring. To address this issue, we developed a new concept for a holder device allowing us to prepare a sample container made of hydrogel. The production process of this holder is based on 3D printing of both a frame and casting devices. The simplicity of production and the advantages of this versatile new sample holder are shown with time-lapse recording of multicellular tumour spheroid growth. More importantly, we also show that cell division is not impaired in contrast to what is observed with gel embedding. The benefit of this new holder for other sample types, applications and experiments remains to be evaluated, but this innovative concept of fully customizable sample holder preparation potentially represents a major step forward to facilitate the large diffusion of single plane illumination microscopy technology.

  19. Deformation Twinning During Nanoindentation of Nanocrystalline Ta

    OpenAIRE

    Wang, Y. M.; Hodge, A. M.; Biener, J.; Hamza, A.V.; Barnes, D E; Liu, Kai; Nieh, T. G.

    2005-01-01

    The deformation mechanism of body-centered cubic (bcc) nanocrystalline tantalum with grain sizes of 10–30 nm is investigated by nanoindentation, scanning electron microscopy and high-resolution transmission electron microscopy. In a deviation from molecular dynamics simulations and existing experimental observations on other bcc nanocrystalline metals, the plastic deformation of nanocrystalline Ta during nanoindentation is controlled by deformation twinning. The observation of multiple twin i...

  20. Creep characterization of solder bumps using nanoindentation

    Science.gov (United States)

    Du, Yingjie; Liu, Xiao Hu; Fu, Boshen; Shaw, Thomas M.; Lu, Minhua; Wassick, Thomas A.; Bonilla, Griselda; Lu, Hongbing

    2017-08-01

    Current nanoindentation techniques for the measurement of creep properties are applicable to viscoplastic materials with negligible elastic deformations. A new technique for characterization of creep behavior is needed for situations where the elastic deformation plays a significant role. In this paper, the effect of elastic deformation on the determination of creep parameters using nanoindentation with a self-similar nanoindenter tip is evaluated using finite element analysis (FEA). It is found that the creep exponent measured from nanoindentation without taking into account of the contribution of elastic deformation tends to be higher than the actual value. An effective correction method is developed to consider the elastic deformation in the calculation of creep parameters. FEA shows that this method provides accurate creep exponent. The creep parameters, namely the creep exponent and activation energy, were measured for three types of reflowed solder bumps using the nanoindentation method. The measured parameters were verified using FEA. The results show that the new correction approach allows extraction of creep parameters with precision from nanoindentation data.

  1. Holder for rotating glass body

    Science.gov (United States)

    Kolleck, Floyd W.

    1978-04-04

    A device is provided for holding and centering a rotating glass body such as a rod or tube. The device includes a tubular tip holder which may be held in a lathe chuck. The device can utilize a variety of centering tips each adapted for a particular configuration, such as a glass O-ring joint or semi-ball joint.

  2. Freeze Protection in Gas Holders

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Duursma, Gail

    In cold weather, the water seals of gasholders need protection from freez- ing to avoid compromising the seal. These holders have a large reservoir of “tank water” at the base which is below ground. At present freeze- protection is achieved by external heating of the seal water which is in a slot...

  3. Working electrode holder and electrochemical cell

    DEFF Research Database (Denmark)

    2016-01-01

    The present disclosure relates to a holder for a test object, more specifically to a holder for measuring electrochemical properties of the test object. One embodiment relates to a working electrode holder for measuring electrochemical properties of a front surface of a test object in a liquid...... in the bottom surface and configured for passage of said liquid, such that liquid is able to pass onto the electrically contacted front surface. The holder may be used in an electrochemical cell....

  4. 7 CFR 1401.8 - Subsequent holders.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Subsequent holders. 1401.8 Section 1401.8 Agriculture... PAYMENT § 1401.8 Subsequent holders. (a) General. A person who acquires a commodity certificate from another person shall be considered to be a “subsequent holder” of the certificate. Subsequent holders...

  5. Sample holder support for microscopes

    Science.gov (United States)

    Berry, Anthony (Inventor); Nerren, Billy H. (Inventor)

    1991-01-01

    A sample filter holder is disclosed for use with a microscope for holding the filter in a planar condition on the stage of the microscope so that automatic focusing of the microscope can be performed on particle samples dispersed on the filter. The holder includes a base having a well that communicates with an inlet port which is connected to a suction pump. A screen assembly is positioned within the well. The screen assembly includes a disk having a screen positioned on its top surface and secured to the disk at the peripheral edge of the screen. Small bores allow the outer surface of the screen to communicate with the well. The filter is placed on the screen and is held in a flat disposition by the suction forces.

  6. Nanoindentation: Toward the sensing of atomic interactions

    Science.gov (United States)

    Fraxedas, J.; Garcia-Manyes, S.; Gorostiza, P.; Sanz, F.

    2002-04-01

    The mechanical properties of surfaces of layered materials (highly oriented pyrolytic graphite, InSe, and GaSe) and single-crystal ionic materials (NaCl, KBr, and KCl) have been investigated at the nanometer scale by using nanoindentations produced with an atomic force microscope with ultrasharp tips. Special attention has been devoted to the elastic response of the materials before the onset of plastic yield. A new model based on an equivalent spring constant that takes into account the changes in in-plane interactions on nanoindentation is proposed. The results of this model are well correlated with those obtained by using the Debye model of solid vibrations.

  7. Development of a new endoscope holder for head and neck surgery--from the technical design concept to implementation.

    Science.gov (United States)

    Kristin, Julia; Kolmer, Armin; Kraus, Peter; Geiger, Robert; Klenzner, Thomas

    2015-05-01

    Endoscope holders are utilized by a variety of surgeons but are not commonplace in head and neck surgery. The SOLOASSIST active camera holder, which is currently used for abdominal surgery, will soon be adapted for head and neck surgery in collaboration with AKTORmed GmbH SOLO SURGERY (Barbing, Germany). In our pre-feasibility study, we analyzed the use of the existing endoscope holder on anatomical specimens during head and neck surgery. Based on these results, we are proceeding towards the development of a new endoscope holder for head and neck surgery. First, we drafted the technical concepts and discussed the advantages and disadvantages of the system. Then, we used anatomic specimens to measure the forces that occur intraoperatively during sinus surgery. Next, we designed a computer-aided design (CAD) model. Finally, we developed the first production prototype and used it for a frontal skull base procedure on an anatomical specimen. We present the three most promising concepts for a new holder. The resulting total force (F res = √(X (2) + Y (2) + Z (2))) was calculated to be 3.2 N during sinus surgery. We could observe all necessary intraoperative landmarks with the endoscope and its holder in a sinus and frontal skull base surgery. We developed a production prototype of a new endoscope holder and demonstrate satisfactory results in the use of anatomic specimens for skull base surgery.

  8. SQUID holder with high magnetic shielding

    Science.gov (United States)

    Rigby, K. W.; Marek, D.; Chui, T. C. P.

    1990-01-01

    A SQUID holder designed for high magnetic shielding is discussed. It is shown how to estimate the attenuation of the magnetic field from the normal magnetic modes for an approximate geometry. The estimate agrees satisfactorily with the attenuation measured with a commercial RF SQUID installed in the holder. The holder attenuates external magnetic fields by more than 10 to the 9th at the SQUID input. With the SQUID input shorted, the response to external fields is 0.00001 Phi(0)/G.

  9. Solid-state-laser-rod holder

    Science.gov (United States)

    Gettemy, D.J.; Barnes, N.P.; Griggs, J.E.

    1981-08-11

    The disclosure relates to a solid state laser rod holder comprising Invar, copper tubing, and epoxy joints. Materials and coefficients of expansion of the components of the holder combine with the rod to produce a joint which will give before the rod itself will. The rod may be lased at about 70 to 80/sup 0/K and returned from such a temperature to room temperature repeatedly without its or the holder's destruction.

  10. Comparative study of helium effects on EU-ODS EUROFER and EUROFER97 by nanoindentation and TEM

    Energy Technology Data Exchange (ETDEWEB)

    Roldán, M., E-mail: marcelo.roldan@ciemat.es [National Fusion Laboratory – CIEMAT, Avda. Complutense, 40, 28040 Madrid (Spain); Fernández, P. [National Fusion Laboratory – CIEMAT, Avda. Complutense, 40, 28040 Madrid (Spain); Rams, J. [Departamento de Matemática Aplicada, Ciencia e Ingeniería de Materiales y Tecnología Electrónica, ESCET, Universidad Rey Juan Carlos, C/Tulipán s/n, Móstoles, Madrid 28933 (Spain); Jiménez-Rey, D. [Centre for Micro-Analysis of Materials (CMAM, UAM), C/Faraday 3, 28049 Madrid (Spain); Materna-Morris, E.; Klimenkov, M. [Karlsruhe Institute of Technology (KIT), Institute for Advanced Materials (IAM-AWP), Hermann-von-Helmholtz-Platz, 1, 76344 Eggenstein-Leopoldshafen, Karlsruhe (Germany)

    2015-05-15

    Highlights: • EU-ODS EUROFER has been studied before and after He implantation by nanoindentation. • Specimens implanted in stair-like profile from 15 to 2 MeV (750 to 350 appm He). • Exhaustive comparison of nanoindentation results with EUROFER97 is presented. • TEM on EUROFER97 and EU-ODSEUROFER to correlate microstructure with hardness results. - Abstract: Helium effects on EU-ODS EUROFER were studied by means of nanoindentation and TEM. The results were compared with those of EUROFER97. Both steels were implanted in a stair-like profile configuration using energies from 2 MeV (maximum He content ∼750 appm He) to 15 MeV (minimum He ∼350 appm He) at room temperature. The nanoindentation tests on He implanted samples showed a hardness increase that depended on the He concentration. The maximum hardness increase observed at 5 mN was 21% in EU-ODS EUROFER and 41% in EUROFER97; it corresponded with the zone with the highest He concentration which was around 750 appm, according to MARLOWE simulation. In addition, FIB lamellae were prepared from EUROFER97 and EU-ODS EUROFER containing the aforementioned zones with maximum (750 appm) and minimum (300 appm) He. TEM investigations carried out showed small and homogeneously distributed He nanobubbles on both alloys in the zone corresponding with maximum He content. These microstructural features seem to be the cause of the hardness increase measured by nanoindentation.

  11. Durability of crystalline phase in concrete microstructure modified by the mineral powders: evaluation by nanoindentation tests

    Directory of Open Access Journals (Sweden)

    Rajczakowska Magdalena

    2016-03-01

    Full Text Available This paper presents the nanoindentation investigation of the evolution of concrete microstructure modified by the Internal Crystallization Technology mineral powders. The samples under study were retrieved from a fragment of a circular concrete lining of the vertical mine shaft at a depth of approximately 1,000 m. Due to the aggressive environment and exposure to contaminated water, the internal surface of the structure was deteriorated, decreasing its strength significantly. The mineral powders were applied directly on the surface lining. The specimens were investigated one month, three months and one year after the application of the aforementioned substance in order to verify the time dependence of the strengthening processes and durability of the crystalline phase. The microstructural changes of concrete were assessed with the use of nanoindentation technique. The testing procedure involved including the previously cut specimens in the epoxy resin and grinding and polishing in order to reduce the surface roughness. As a result of the nanoindentation tests the hardness as well as Young’s modulus of the material were evaluated. The results were then compared and statistically analyzed. As a consequence, the disintegration time of the crystalline network in the pores of concrete was identified.

  12. 3D print customized sample holders for live light sheet microscopy.

    Science.gov (United States)

    Jeandupeux, Emeric; Lobjois, Valérie; Ducommun, Bernard

    2015-08-01

    A major hurdle to the widespread application of light sheet microscopy is the lack of versatile and non-intrusive sample holders that are adaptable to a variety of biological samples for live imaging. To overcome this limitation, we present herein the application of 3D printing to the fabrication of a fully customizable casting kit. 3D printing enables facile preparation of hydrogel sample holders adaptable to any shape and number of specimen. As an example, we present the use of this device to produce a four-sample holder adapted to parallel live monitoring of multicellular tumor spheroid growth. To share our solution with the light sheet microscopy community, all files necessary to produce or customize sample holders are freely available online.

  13. Influence of bowl shaped substrate holder on growth of polymeric DLC film in a microwave plasma CVD reactor

    Indian Academy of Sciences (India)

    Sambita Sahoo; S K Pradhan; Venkateswarlu Bhavanasi; Swati S Pradhan; S N Sarangi; P K Barhai

    2012-12-01

    The properties of diamond like carbon (DLC) films grown in modified microwave plasma CVD reactor is presented in this paper. By using bowl shaped steel substrate holder in a MW plasma CVD reactor (without ECR), films have been grown at relatively high pressure (20Torr) and at low temperature (without heating). The input microwave power was about 300W. Earlier, under the same growth conditions, no deposition was achieved when flat molybdenum/steel substrate holders were used. In this study, two different designs of bowl shaped steel substrate holder at different bias have been experimented. Raman spectra confirm the DLC characteristics of the films. FTIR results indicate that the carbon is bonded in the 3 form with hydrogen, and this characteristic is more pronounced when smaller holder is used. UV-visible spectra show high visible transmittance (∼85%) for films grown in both the holders. The nanoindentation hardness of the films have a wide range, about 4–16GPa. Field emission scanning electron microscope (FESEM) images reveal that the films have featureless and smooth surface morphology. These films are polymeric in nature with moderately high hardness, which may be useful as anti-scratch and anti-corrosive coatings.

  14. On the Nanoindentation of the Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Petre P. Teodorescu

    2010-01-01

    Full Text Available A new inverse approach is proposed in this paper, which combines elements of nonlocal theory and molecular mechanics, based on the experimental results available in the nanoindentation literature. The effect of the inlayer van der Waals atomistic interactions for carbon nanotubes with multiple walls (MWCNT is included by means of the Brenner-Tersoff potential and experimental results. The neighboring walls of MWCNT are coupled through van der Waals interactions, and the shell buckling would initiate in the outermost shell, when nanotubes are short. The nanoindentation technique is simulated for the axially compressed of individual nanotubes, in order to evaluate the load-unloaded-displacement, the curve critical buckling and the appropriate values for local Lamé constants.

  15. Interfacial diffusion aided deformation during nanoindentation

    Science.gov (United States)

    Samanta, Amit; E, Weinan

    2016-07-01

    Nanoindentation is commonly used to quantify the mechanical response of material surfaces. Despite its widespread use, a detailed understanding of the deformation mechanisms responsible for plasticity during these experiments has remained elusive. Nanoindentation measurements often show stress values close to a material's ideal strength which suggests that dislocation nucleation and subsequent dislocation activity dominates the deformation. However, low strain-rate exponents and small activation volumes have also been reported which indicates high temperature sensitivity of the deformation processes. Using an order parameter aided temperature accelerated sampling technique called adiabatic free energy dynamics [J. B. Abrams and M. E. Tuckerman, J. Phys. Chem. B, 112, 15742 (2008)], and molecular dynamics we have probed the diffusive mode of deformation during nanoindentation. Localized processes such as surface vacancy and ad-atom pair formation, vacancy diffusion are found to play an important role during indentation. Our analysis suggests a change in the dominant deformation mode from dislocation mediated plasticity to diffusional flow at high temperatures, slow indentation rates and small indenter tip radii.

  16. Freeze Protection in Gas Holders

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Duursma, Gail

    In cold weather, the water seals of gasholders need protection from freez- ing to avoid compromising the seal. These holders have a large reservoir of “tank water” at the base which is below ground. At present freeze- protection is achieved by external heating of the seal water which...... is in a slotted channel called a cup. Electrical heating or circulation of heated tank water to the cup are examples of systems presently used. The tank water has a large thermal capacity and National Grid wishes to inves- tigate whether circulation of the tank water without external heating could provide...... sufficient energy input to avoid freezing. Only tanks in which the tank water is below ground are investigated in the report. The soil temperature under the reservoir at depth of 10m and lower is almost constant....

  17. 7 CFR 930.60 - Equity holders.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Equity holders. 930.60 Section 930.60 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Regulations § 930.60 Equity holders. (a) Inventory reserve ownership. The inventory reserve shall be the...

  18. Plastic zone size for nanoindentation of irradiated Fesbnd 9%Cr ODS

    Science.gov (United States)

    Dolph, Corey K.; da Silva, Douglas J.; Swenson, Matthew J.; Wharry, Janelle P.

    2016-12-01

    The objective of this study is to determine irradiation effects on the nanoindentation plastic zone morphology in a model Fe-9%Cr ODS alloy. Specimens are irradiated to 50 displacements per atom at 400°C with Fe++ self-ions or to 3 dpa at 500°C with neutrons. The as-received specimen is also studied as a control. The nanoindentation plastic zone size is calculated using two approaches: (1) an analytical model based on the expanding spherical cavity analogy, and (2) finite element modeling (FEM). Plastic zones in all specimen conditions extend radially outward from the indenter, ∼4-5 times the tip radius, indicative of fully plastic contact. Non-negligible plastic flow in the radial direction requires the experimentalist to consider the plastic zone morphology when nanoindenting ion-irradiated specimens; a single nanoindent may sample non-uniform irradiation damage, regardless of whether the indent is made top-down or in cross-section. Finally, true stress-strain curves are generated.

  19. Virtual Specimens

    Science.gov (United States)

    de Paor, D. G.

    2009-12-01

    Virtual Field Trips have been around almost as long as the Worldwide Web itself yet virtual explorers do not generally return to their desktops with folders full of virtual hand specimens. Collection of real specimens on fields trips for later analysis in the lab (or at least in the pub) has been an important part of classical field geoscience education and research for generations but concern for the landscape and for preservation of key outcrops from wanton destruction has lead to many restrictions. One of the author’s favorite outcrops was recently vandalized presumably by a geologist who felt the need to bash some of the world’s most spectacular buckle folds with a rock sledge. It is not surprising, therefore, that geologists sometimes leave fragile localities out of field trip itineraries. Once analyzed, most specimens repose in drawers or bins, never to be seen again. Some end up in teaching collections but recent pedagogical research shows that undergraduate students have difficulty relating specimens both to their collection location and ultimate provenance in the lithosphere. Virtual specimens can be created using 3D modeling software and imported into virtual globes such as Google Earth (GE) where, they may be linked to virtual field trip stops or restored to their source localities on the paleo-globe. Sensitive localities may be protected by placemark approximation. The GE application program interface (API) has a distinct advantage over the stand-alone GE application when it comes to viewing and manipulating virtual specimens. When instances of the virtual globe are embedded in web pages using the GE plug-in, Collada models of specimens can be manipulated with javascript controls residing in the enclosing HTML, permitting specimens to be magnified, rotated in 3D, and sliced. Associated analytical data may be linked into javascript and localities for comparison at various points on the globe referenced by ‘fetching’ KML. Virtual specimens open up

  20. Evaluation of the degradation of plasma sprayed thermal barrier coatings using nano-indentation.

    Science.gov (United States)

    Kim, Dae-Jin; Cho, Sung-Keun; Choi, Jung-Hun; Koo, Jae-Mean; Seok, Chang-Sung; Kim, Moon-Young

    2009-12-01

    In this study, the disk type of a thermal barrier coating (TBC) system for a gas turbine blade was isothermally aged at 1100 degrees C for various times up to 400 hours. For each aging condition, the thickness of the thermally grown oxide (TGO) was measured by optical microscope and mechanical properties such as the elastic modulus and hardness were measured by micro-indentation and nano-indentation on the cross-section of a coating specimen. In the case of micro-indentation, the mechanical properties of a Ni-base superalloy substrate and MCrAlY bond coat material did not significantly change with an increase in exposure time. In the case of nano-indentation, the gamma-Ni phase and beta-NiAl phase in the bond coat and top coat material show no significant change in their properties. However, the elastic modulus and the hardness of TGO show a remarkable decrease from 100 h to 200 h then remain nearly constant after 200 h due to the internal delamination of TBC. It has been confirmed that the nano-indentation technique is a very effective way to evaluate the degradation of a thermal barrier coating system.

  1. Hardening by twin boundary during nanoindentation in nanocrystals.

    Science.gov (United States)

    Qu, Shaoxing; Zhou, Haofei

    2010-08-20

    The atomistic deformation processes of nanocrystals embedded with nanoscale twin boundaries during nanoindentation are studied by molecular dynamics simulations. Load-displacement curves are obtained and the hardening mechanisms associated with the nanoscale twin boundaries are revealed. Johnson's theoretical indentation model is adopted to estimate the elastic stage of the nanoindentation. In addition, twin boundary-mediated dislocation nucleation is observed and analyzed.

  2. Evaluation of irradiation hardening of proton irradiated stainless steels by nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Yabuuchi, Kiyohiro, E-mail: kiyohiro.yabuuchi@qse.tohoku.ac.jp [Graduate School of Engineering, Tohoku University, 6-6-01-2 Aramaki-Aza-Aoba, Aobaku, Sendai, Miyagi 980-8579 (Japan); Kuribayashi, Yutaka [Graduate School of Engineering, Tohoku University, 6-6-01-2 Aramaki-Aza-Aoba, Aobaku, Sendai, Miyagi 980-8579 (Japan); Nogami, Shuhei, E-mail: shuhei.nogami@qse.tohoku.ac.jp [Graduate School of Engineering, Tohoku University, 6-6-01-2 Aramaki-Aza-Aoba, Aobaku, Sendai, Miyagi 980-8579 (Japan); Kasada, Ryuta, E-mail: r-kasada@iae.kyoto-u.ac.jp [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Hasegawa, Akira, E-mail: akira.hasegawa@qse.tohoku.ac.jp [Graduate School of Engineering, Tohoku University, 6-6-01-2 Aramaki-Aza-Aoba, Aobaku, Sendai, Miyagi 980-8579 (Japan)

    2014-03-15

    Ion irradiation experiments are useful for investigating irradiation damage. However, estimating the irradiation hardening of ion-irradiated materials is challenging because of the shallow damage induced region. Therefore, the purpose of this study is to prove usefulness of nanoindentation technique for estimation of irradiation hardening for ion-irradiated materials. SUS316L austenitic stainless steel was used and it was irradiated by 1 MeV H{sup +} ions to a nominal displacement damage of 0.1, 0.3, 1, and 8 dpa at 573 K. The irradiation hardness of the irradiated specimens were measured and analyzed by Nix–Gao model. The indentation size effect was observed in both unirradiated and irradiated specimens. The hardness of the irradiated specimens changed significantly at certain indentation depths. The depth at which the hardness varied indicated that the region deformed by the indenter had reached the boundary between the irradiated and unirradiated regions. The hardness of the irradiated region was proportional to the inverse of the indentation depth in the Nix–Gao plot. The bulk hardness of the irradiated region, H{sub 0}, estimated by the Nix–Gao plot and Vickers hardness were found to be related to each other, and the relationship could be described by the equation, HV = 0.76H{sub 0}. Thus, the nanoindentation technique demonstrated in this study is valuable for measuring irradiation hardening in ion-irradiated materials.

  3. EBSD and Nanoindentation-Correlated Study of Delamination Fracture in Al-Li Alloy 2090

    Science.gov (United States)

    Tayon, Wesley A.; Crooks, Roy E.; Domack, Marcia S.; Wagner, John A.; Elmustafa, A. A.

    2008-01-01

    Al-Li alloys offer attractive combinations of high strength and low density. However, a tendency for delamination fracture has limited their use. A better understanding of the delamination mechanisms may identify methods to control delaminations through processing modifications. A combination of new techniques has been used to evaluate delamination fracture in Al-Li alloys. Both high quality electron backscattered diffraction (EBSD) information and valid nanoindentation measurements were obtained from fractured test specimens. Correlations were drawn between nano-scale hardness variations and local texture along delaminating boundaries. Intriguing findings were observed for delamination fracture through the combined analysis of grain orientation, Taylor factor, and kernel average misorientation.

  4. Elastic constants determined by nanoindentation for p-type thermoelectric half-Heusler

    Energy Technology Data Exchange (ETDEWEB)

    Gahlawat, S.; Wheeler, L.; White, K. W., E-mail: zren@uh.edu, E-mail: kwwhite@uh.edu [Department of Mechanical Engineering, University of Houston, Houston, Texas 77204 (United States); He, R.; Chen, S.; Ren, Z. F., E-mail: zren@uh.edu, E-mail: kwwhite@uh.edu [Department of Physics and TcSUH, University of Houston, Houston, Texas 77204 (United States)

    2014-08-28

    This paper presents a study of the elastic properties of the p-type thermoelectric half-Heusler material, Hf{sub 0.44}Zr{sub 0.44}Ti{sub 0.12}CoSb{sub 0.8}Sn{sub 0.2}, using nanoindentation. Large grain-sized polycrystalline specimens were fabricated for these measurements, providing sufficient indentation targets within single grains. Electron Backscatter Diffraction methods indexed the target grains for the correlation needed for our elastic analysis of individual single crystals for this cubic thermoelectric material. Elastic properties, including the Zener ratio and the Poisson ratio, obtained from the elasticity tensor are also reported.

  5. Deformation Mechanisms of Gum Metals Under Nanoindentation

    Science.gov (United States)

    Sankaran, Rohini Priya

    defect structures to applied loading, we perform ex-situ nanoindentation. Nanoindentation is a convenient method as the plastic deformation is localized and probes a nominally defect free volume of the material. We subsequently characterize the defect structures in these alloys with both conventional TEM and advanced techniques such as HAADF HRSTEM and nanoprobe diffraction. These advanced techniques allow for a more thorough understanding of the observed deformation features. The main findings from this investigation are as follows. As expected we observe that a non-equilibrium phase, o, is present in the leaner beta-stabilized alloy, ST Ref-1. We do not find any direct evidence of secondary phases in STGM, and we find the beta phase in CWGM, along with lath microstructure with subgrain structure consisting of dislocation cell networks. Upon nanoindentation, we find twinning accompanied by beta nucleation on the twin boundary in ST Ref-1 samples. This result is consistent with previous findings and is reasonable considering the alloy is unstable with respect to beta transformation. We find deformation nanotwinning in cold worked gum metals under nanoindentation, which is initially surprising. We argue that when viewed as a nanocrystalline material, such a deformation mechanism is consistent with previous work, and furthermore, a deformation nanotwinned structure does not preclude an ideal shear mechanism from operating in the alloy. Lastly, we observe continuous lattice rotations in STGM under nanoindentation via nanoprobe diffraction. With this technique, for the first time we can demonstrate that the lattice rotations are truly continuous at the nanoscale. We can quantify this lattice rotation, and find that even though the rotation is large, it may be mediated by a reasonable geometrically necessary dislocation density, and note that similar rotations are typically observed in other materials under nanoindentation. HRSTEM and conventional TEM data confirm the

  6. Silicon Holder For Molecular-Beam Epitaxy

    Science.gov (United States)

    Hoenk, Michael E.; Grunthaner, Paula J.; Grunthaner, Frank J.

    1993-01-01

    Simple assembly of silicon wafers holds silicon-based charge-coupled device (CCD) during postprocessing in which silicon deposited by molecular-beam epitaxy. Attains temperatures similar to CCD, so hotspots suppressed. Coefficients of thermal expansion of holder and CCD equal, so thermal stresses caused by differential thermal expansion and contraction do not develop. Holder readily fabricated, by standard silicon processing techniques, to accommodate various CCD geometries. Silicon does not contaminate CCD or molecular-beam-epitaxy vacuum chamber.

  7. Bone properties by nanoindentation in mild and severe osteogenesis imperfecta.

    Science.gov (United States)

    Albert, Carolyne; Jameson, John; Toth, Jeffrey M; Smith, Peter; Harris, Gerald

    2013-01-01

    Osteogenesis imperfecta is a heterogeneous genetic disorder characterized by bone fragility. Previous research suggests that impaired collagen network and abnormal mineralization affect bone tissue properties, however, little data is yet available to describe bone material properties in individuals with this disorder. Bone material properties have not been characterized in individuals with the most common form of osteogenesis imperfecta, type I. Bone tissue elastic modulus and hardness were measured by nanoindentation in eleven osteotomy specimens that were harvested from children with osteogenesis imperfecta during routine surgeries. These properties were compared between osteogenesis imperfecta types I (mild, n=6) and III (severe, n=5), as well as between interstitial and osteonal microstructural regions using linear mixed model analysis. Disease severity type had a small but statistically significant effect on modulus (7%, P=0.02) and hardness (8%, Posteogenesis imperfecta type I had higher modulus and hardness than did those with type III. Overall, mean modulus and hardness values were 13% greater in interstitial lamellar bone regions than in osteonal regions (Posteogenesis imperfecta, i.e., type I. Results indicate that intrinsic bone tissue properties are affected by phenotype. Knowledge of the material properties of bones in osteogenesis imperfecta will contribute to the ability to develop models to assist in predicting fracture risk. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Fracture toughness of bleached enamel: Effect of applying three different nanobiomaterials by nanoindentation test

    Directory of Open Access Journals (Sweden)

    Maryam Khoroushi

    2016-01-01

    Full Text Available Background: Despite the absence of dispute about the efficacy of bleaching agents, a prime concern is about their compromising effect on the enamel structure. This in vitro study investigated whether the addition of three different biomaterials, including nano-bioactive glass (n-BG/nano-hydroxy apetite (n-HA/nano-amorphous calcium phosphate (n-ACP, to bleaching agents can affect the fracture toughness (FT and vickers hardness number (VHN of bovine enamel. Materials and Methods: The crowns of the newly extracted permanent bovine incisors teeth were separated from the root and sectioned along their central line; one half serving as the control specimen and the other half as the test specimen. After mounting and polishing procedure, all the control specimens (C were subjected to nano-indentation test to obtain the baseline values of FT. Then, the control specimens were exposed to a 38% hydrogen peroxide for four times, each time for 10 min. The test specimens were divided into three groups and treated as follows, with the same protocol used for the control specimens: Group 1; ACP + hydrogen peroxide (HP mixed gel; Group 2 BG + HP mixed gel; and Group 3 HA + HP mixed gel. FT measurements with nano-indentation were carried out subsequent to bleaching experiments. Data were analyzed using SPSS and Kruskal–Wallis test (α = 0.05. Results: A significant difference in young's modulus (YM, VHN, and FT at baseline and subsequent to bleaching in control group was observed. However, no significant differences were found in YM, VHN, and FT between the test groups, compared to the respective baseline values. Conclusion: Under the limitations of the current study, it can be concluded that the n-HA, n-ACP, and n-BG could be potential biomaterials used to reduce the adverse effects of tooth bleaching.

  9. Report on the Installation and Preparedness of a Protochips Fusion in-situ Heating Holder for TEM

    Energy Technology Data Exchange (ETDEWEB)

    Edmondson, Philip D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-03-01

    This brief report documents the procurement and installation of a Protochips Fusion (formerly Aduro) high-temperature, high stability transmission electron microscopy (TEM) specimen holder that allows for the high spatial resolution characterization of material specimens at high temperature in situ of an electron microscope. This specimen holder was specifically procured for use with The FEI Talos F200X Scanning/Transmission Electron Microscope (STEM) in Oak Ridge National Laboratory’s (ORNL’s) Low Activation Materials Development and Analysis (LAMDA) Laboratory. The Protochips Fusion holder will enable high-resolution structural and chemical analysis of irradiated materials at high temperature, becoming a unique capability worldwide, and would encourage high-quality in situ experiments to be conducted on irradiated materials.

  10. 14 CFR 183.57 - Responsibilities of an ODA Holder.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Responsibilities of an ODA Holder. 183.57... Authorization § 183.57 Responsibilities of an ODA Holder. The ODA Holder must— (a) Comply with the procedures... performance of oversight of the ODA Holder and the ODA Unit. (e) Notify the Administrator of any change...

  11. 38 CFR 36.4341 - Death or insolvency of holder.

    Science.gov (United States)

    2010-07-01

    ... holder. 36.4341 Section 36.4341 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS... Death or insolvency of holder. (a) Immediately upon the death of the holder and without the necessity of... any unpaid taxes, insurance premiums, ground rents, or advances may be paid by the holder of...

  12. 40 CFR 85.1507 - Maintenance of certificate holder's records.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Maintenance of certificate holder's... Vehicle Engines § 85.1507 Maintenance of certificate holder's records. (a) The certificate holder subject... date of entry of a nonconforming vehicle or engine imported by the certificate holder,...

  13. 19 CFR 10.7 - Substantial containers or holders.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Substantial containers or holders. 10.7 Section 10... Exported and Returned § 10.7 Substantial containers or holders. (a) Substantial containers or holders... domestic products exported and returned. When such containers or holders are imported not containing...

  14. 17 CFR 229.507 - (Item 507) Selling security holders.

    Science.gov (United States)

    2010-04-01

    ... holders. 229.507 Section 229.507 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION... Provisions § 229.507 (Item 507) Selling security holders. If any of the securities to be registered are to be offered for the account of security holders, name each such security holder, indicate the nature of...

  15. Nano-Indentation of Anisotropic Material: Numerical Approaches to Extract Elasticities from Nano-Indentation

    OpenAIRE

    Sveaass, Tore

    2013-01-01

    Division of Biomechanics participates in a project together with Department of Cancer Research and Molecular Medicine, NTNU, on effects of proton pump inhibitor medication on bone quality. This common anti-stomach acid medication seems to result in an increased bone fragility in humans. As a step towards comparing mechanical properties at micro level, between sick and healthy bone tissue, mice femur have been tested at micro level using the increasingly popular tool, nanoindentation. Futher, ...

  16. Nano-Indentation of Anisotropic Material: Numerical Approaches to Extract Elasticities from Nano-Indentation

    OpenAIRE

    Sveaass, Tore

    2013-01-01

    Division of Biomechanics participates in a project together with Department of Cancer Research and Molecular Medicine, NTNU, on effects of proton pump inhibitor medication on bone quality. This common anti-stomach acid medication seems to result in an increased bone fragility in humans. As a step towards comparing mechanical properties at micro level, between sick and healthy bone tissue, mice femur have been tested at micro level using the increasingly popular tool, nanoindentation. Futher, ...

  17. Fracture Toughness Properties of Three Different Biomaterials Measured by Nanoindentation

    Institute of Scientific and Technical Information of China (English)

    Ji-yu Sun; Jin Tong

    2007-01-01

    The fracture toughness of hard biomaterials,such as nacre,bovine hoof wall and beetle cuticle,is associated with fibrous or lamellar structures that deflect or stop growing cracks.Their hardness and reduced modulus were measured by using a nanoindenter in this paper.Micro/nanoscale cracks were generated by nanoindentation using a Berkovich tip.Nanoindentation of nacre and bovine hoof wall resulted in pile-up around the indent.It was found that the fracture toughness(Kc)of bovine hoof wall is the maximum,the second is nacre,and the elytra cuticle of dung beetle is the least one.

  18. Nanoindentation shape effect: experiments, simulations and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Calabri, L [CNR-INFM-National Research Center on nanoStructures and bioSystems at Surfaces (S3), Via Campi 213/a, 41100 Modena (Italy); Pugno, N [Department of Structural Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin (Italy); Rota, A [CNR-INFM-National Research Center on nanoStructures and bioSystems at Surfaces (S3), Via Campi 213/a, 41100 Modena (Italy); Marchetto, D [CNR-INFM-National Research Center on nanoStructures and bioSystems at Surfaces (S3), Via Campi 213/a, 41100 Modena (Italy); Valeri, S [CNR-INFM-National Research Center on nanoStructures and bioSystems at Surfaces (S3), Via Campi 213/a, 41100 Modena (Italy)

    2007-10-03

    AFM nanoindentation is nowadays commonly used for the study of mechanical properties of materials at the nanoscale. The investigation of surface hardness of a material using AFM means that the probe has to be able to indent the surface, but also to image it. Usually standard indenters are not sharp enough to obtain high-resolution images, but on the other hand measuring the hardness behaviour of a material with a non-standard sharp indenter gives only comparative results affected by a significant deviation from the commonly used hardness scales. In this paper we try to understand how the shape of the indenter affects the hardness measurement, in order to find a relationship between the measured hardness of a material and the corner angle of a pyramidal indenter. To achieve this we performed a full experimental campaign, indenting the same material with three focused ion beam (FIB) nanofabricated probes with a highly altered corner angle. We then compared the results obtained experimentally with those obtained by numerical simulations, using the finite element method (FEM), and by theoretical models, using a general scaling law for nanoindentation available for indenters with a variable size and shape. The comparison between these three approaches (experimental, numerical and theoretical approaches) reveals a good agreement and allowed us to find a theoretical relationship which links the measured hardness value with the shape of the indenter. The same theoretical approach has also been used to fit the hardness experimental results considering the indentation size effect. In this case we compare the measured data, changing the applied load.

  19. Diabetes management in Commercial Driver License holders.

    Science.gov (United States)

    Kerr, Jessica L; Frichtl, Kelsey D; Behnen, Erin M

    2015-04-01

    The purpose of this study is to evaluate diabetes management in Commercial Driver License (CDL) holders, how prescribing habits change when treating this patient population, and health care providers' knowledge of regulations concerning insulin use in CDL holders. A survey was posted on the American Association of Diabetes Educators (AADE) Communities of Interest websites and was open for 2 weeks. The anonymous survey collected demographic data and evaluated the perspectives of health care providers on diabetes management in CDL holders. Descriptive statistics were used to analyze the survey results. A total of 139 AADE members responded to the survey, and 22.2% were prescribing providers. Findings from the survey indicated an overall lack of knowledge by health care professionals regarding the current laws affecting diabetes management in CDL holders. Most participants emphasized the need for making decisions on CDL suspension on a case-by-case basis, and some expressed concern that current laws may not be appropriate. Additional diabetes education for health care providers who treat CDL holders is warranted as many health care providers were not familiar with current regulations and management strategies. © 2015 The Author(s).

  20. The effectiveness of an endotracheal tube holder

    Directory of Open Access Journals (Sweden)

    Byung Gun Lim

    2016-01-01

    Full Text Available The security of the endotracheal tube (ETT is important in the anesthesia and intensive care settings. Recently, an ETT holder instead of an adhesive tape is frequently used to provide the fixation of the ETT. There are some studies that focused on the effectiveness of the ETT holder in preventing displacement of ETT compared to an adhesive tape (1, 2. I have experienced the use of an ETT holder (E-holder, KS medical, Bucheon, Korea in many different anesthesia settings and recognized its usefulness and convenience other than ETT security in the following specific settings.  Firstly, the ETT holder is definitely effective for patients undergoing procedures that frequently require the adjustment of ETT (or double lumen tube location including thoracic surgery. The location of double lumen tube needed for lung separation can be modified for effective ventilation during anesthetic induction or surgery, and after position changes. The tube can be easily relocated to the proper place for lung separation and effective ventilation by unlocking/relocking the button of the ETT holder under flexible bronchoscopic guidance (Fig. 1A, which can facilitate the operative procedure to be performed easily and quickly. Secondly, the ETT holder can be useful in procedures requiring the prone position (3. Especially, it is useful in all circumstances requiring the adjustment of ETT in the prone position. For instance, it is definitely useful for patients with Duchene muscular dystrophy undergoing scoliosis surgery under prone position. Adolescent patients with Duchene muscular dystrophy frequently have tracheobronchial malacia. If so, the airway pressure can be elevated due to the narrowing of the lesion of malacia when changed to the prone position (4. To overcome this problem, a reinforced ETT should be relocated so that it passes the narrowed tracheal lesion under flexible bronchoscopic guidance (Fig. 1B. However, the approach for this management is somewhat

  1. Characterization of multi-layered fish scales (Atractosteus spatula) using nanoindentation, X-ray CT, FTIR, and SEM.

    Science.gov (United States)

    Allison, Paul G; Rodriguez, Rogie I; Moser, Robert D; Williams, Brett A; Poda, Aimee R; Seiter, Jennifer M; Lafferty, Brandon J; Kennedy, Alan J; Chandler, Mei Q

    2014-07-10

    The hierarchical architecture of protective biological materials such as mineralized fish scales, gastropod shells, ram's horn, antlers, and turtle shells provides unique design principles with potentials for guiding the design of protective materials and systems in the future. Understanding the structure-property relationships for these material systems at the microscale and nanoscale where failure initiates is essential. Currently, experimental techniques such as nanoindentation, X-ray CT, and SEM provide researchers with a way to correlate the mechanical behavior with hierarchical microstructures of these material systems1-6. However, a well-defined standard procedure for specimen preparation of mineralized biomaterials is not currently available. In this study, the methods for probing spatially correlated chemical, structural, and mechanical properties of the multilayered scale of A. spatula using nanoindentation, FTIR, SEM, with energy-dispersive X-ray (EDX) microanalysis, and X-ray CT are presented.

  2. Spherical nanoindentation stress-strain analysis, Version 1

    Energy Technology Data Exchange (ETDEWEB)

    2016-11-07

    Nanoindentation is a tool that allows the mechanical response of a variety of materials at the nano to micron length scale to be measured. Recent advances in spherical nanoindentation techniques have allowed for a more reliable and meaningful characterization of the mechanical response from nanoindentation experiments in the form on an indentation stress-strain curve. This code base, Spin, is written in MATLAB (The Mathworks, Inc.) and based on the analysis protocols developed by S.R. Kalidindi and S. Pathak [1, 2]. The inputs include the displacement, load, harmonic contact stiffness, harmonic displacement, and harmonic load from spherical nanoindentation tests in the form of an Excel (Microsoft) spreadsheet. The outputs include indentation stress-strain curves and indentation properties as well their variance due to the uncertainty of the zero-point correction in the form of MATLAB data (.mat) and figures (.png). [1] S. Pathak, S.R. Kalidindi. Spherical nanoindentation stress–strain curves, Mater. Sci. Eng R-Rep 91 (2015). [2] S.R. Kalidindi, S. Pathak. Determination of the effective zero-point and the extraction of spherical nanoindentation stress-strain curves, Acta Materialia 56 (2008) 3523-3532.

  3. Nanoindentation creep versus bulk compressive creep of dental resin-composites.

    Science.gov (United States)

    El-Safty, S; Silikas, N; Akhtar, R; Watts, D C

    2012-11-01

    To evaluate nanoindentation as an experimental tool for characterizing the viscoelastic time-dependent creep of resin-composites and to compare the resulting parameters with those obtained by bulk compressive creep. Ten dental resin-composites: five conventional, three bulk-fill and two flowable were investigated using both nanoindentation creep and bulk compressive creep methods. For nano creep, disc specimens (15mm×2mm) were prepared from each material by first injecting the resin-composite paste into metallic molds. Specimens were irradiated from top and bottom surfaces in multiple overlapping points to ensure optimal polymerization using a visible light curing unit with output irradiance of 650mW/cm(2). Specimens then were mounted in 3cm diameter phenolic ring forms and embedded in a self-curing polystyrene resin. Following grinding and polishing, specimens were stored in distilled water at 37°C for 24h. Using an Agilent Technologies XP nanoindenter equipped with a Berkovich diamond tip (100nm radius), the nano creep was measured at a maximum load of 10mN and the creep recovery was determined when each specimen was unloaded to 1mN. For bulk compressive creep, stainless steel split molds (4mm×6mm) were used to prepare cylindrical specimens which were thoroughly irradiated at 650mW/cm(2) from multiple directions and stored in distilled water at 37°C for 24h. Specimens were loaded (20MPa) for 2h and unloaded for 2h. One-way ANOVA, Levene's test for homogeneity of variance and the Bonferroni post hoc test (all at p≤0.05), plus regression plots, were used for statistical analysis. Dependent on the type of resin-composite material and the loading/unloading parameters, nanoindentation creep ranged from 29.58nm to 90.99nm and permanent set ranged from 8.96nm to 30.65nm. Bulk compressive creep ranged from 0.47% to 1.24% and permanent set ranged from 0.09% to 0.38%. There was a significant (p=0.001) strong positive non-linear correlation (r(2)=0.97) between bulk

  4. QUASICONTINUUM SIMULATION OF NANOINDENTATION OF NICKEL FILM

    Institute of Scientific and Technical Information of China (English)

    Zeng Fanlin; Sun Yi

    2006-01-01

    A large-scale atom simulation of nanoindentation into a thin nickel film using the quasicontinuum method was performed. The initial stages of the plasticity deformation of nickel were studied. Several useful results were obtained as follows: (1) The response of the load versus indentation depth - on the load versus indentation depth curve, besides the straight parts corresponding to the elastic property of nickel, the sudden drop of the load occurred several times;(2) The phenomena of dislocation nucleation - the dislocation nucleation took place when the load descended, which makes it clear that dislocation nucleation causes the drop of the load; (3)The mechanism of the dislocation emission - the Peierls-Nabarro dislocation model and a powerful criterion were used to analyze the dislocation emission. And the computational value was in good agreement with the predict value; (4) The density of geometrically necessary dislocations.A simple model was used to obtain the density of geometrically necessary dislocations beneath the indenter. Furthermore, the influence of the boundary conditions on the simulation results was discussed.

  5. Twinning anisotropy of tantalum during nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Goel, Saurav, E-mail: S.GOEL@qub.ac.uk [School of Mechanical and Aerospace Engineering, Queen' s University, Belfast, BT9 5AH (United Kingdom); Beake, Ben [Micro Materials Limited, Willow House, Yale Business Village, Ellice Way, Wrexham LL13 7YL (United Kingdom); Dalton Research Institute, Manchester Metropolitan University, Manchester, M15GD (United Kingdom); Chan, Chi-Wai [School of Mechanical and Aerospace Engineering, Queen' s University, Belfast, BT9 5AH (United Kingdom); Haque Faisal, Nadimul [School of Engineering, Robert Gordon University, Garthdee Road, Aberdeen AB10 7GJ (United Kingdom); Dunne, Nicholas [School of Mechanical and Aerospace Engineering, Queen' s University, Belfast, BT9 5AH (United Kingdom)

    2015-03-11

    Unlike other BCC metals, the plastic deformation of nanocrystalline Tantalum (Ta) during compression is regulated by deformation twinning. Whether or not this twinning exhibits anisotropy was investigated through simulation of displacement-controlled nanoindentation test using molecular dynamics (MD) simulation. MD data was found to correlate well with the experimental data in terms of surface topography and hardness measurements. The mechanism of the transport of material was identified due to the formation and motion of prismatic dislocations loops (edge dislocations) belonging to the 1/2〈111〉 type and 〈100〉 type Burgers vector family. Further analysis of crystal defects using a fully automated dislocation extraction algorithm (DXA) illuminated formation and migration of twin boundaries on the (110) and (111) orientation but not on the (010) orientation and most importantly after retraction all the dislocations disappeared on the (110) orientation suggesting twinning to dominate dislocation nucleation in driving plasticity in tantalum. A significant finding was that the maximum shear stress (critical Tresca stress) in the deformation zone exceeded the theoretical shear strength of Ta (Shear modulus/2π~10.03 GPa) on the (010) orientation but was lower than it on the (110) and the (111) orientations. In light of this, the conventional lore of assuming the maximum shear stress being 0.465 times the mean contact pressure was found to break down at atomic scale.

  6. Nanoindentation of Chitosan Doped with Silver Nanoparticles

    Science.gov (United States)

    Palumbo, Matthew; Teklu, Alem; Kuthirummal, Narayanan; Levi-Polyachenko, Nicole; Department of Physics; Astronomy, College of Charleston Collaboration; Department of Plastic; Reconstructive Surgery, Wake Forest University Health Sciences Collaboration

    Imaging and spectroscopic analysis via nanoindentation was performed with the Nanosurf EasyScan2 AFM on the pure and silver doped chitosan samples allowing for a more localized determination of their stiffness, hardness, and reduced Young's modulus. The pure chitosan sample was tested to have a stiffness of 0.367 N/m, a hardness of 1.12 GPa, and a reduced Young's modulus of 30.5 MPa. The film with 5mg Ag nanoparticle per gram of chitosan was tested on the boundaries between the chitosan and Ag nanoparticles to show an increase in stiffness of about 4.6% at 0.384 N/m, an increase in hardness of about 5.4% at 1.18 GPa, and an increase in the reduced Young's modulus of about 5.0% at 3.2 MPa in comparison to the pure chitosan sample. On the other hand, upon increasing the doping to 10mg Ag nanoparticle per gram of chitosan showed a decrease in stiffness of about 6.3% at 0.344 N/m, a decrease in hardness of about 27.0% at 0.820 GPa, and a decrease in the reduced Young's modulus of about 6.0% at 28.7 MPa in comparison to the pure chitosan sample. Obviously, films doped with 5mg Ag nanoparicle per gram of chitosan provided the composites with improved mechanical strength compared to chitosan alone.

  7. Understanding pop-ins in spherical nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Pathak, Siddhartha, E-mail: pathak@lanl.gov, E-mail: siddharthapathak@gmail.com [MPA-CINT Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Riesterer, Jessica L.; Michler, Johann [Empa, Swiss Federal Laboratory for Materials Testing and Research, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkerstrasse 39, Thun 3602 (Switzerland); Kalidindi, Surya R. [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

    2014-10-20

    Pop-ins, or sudden displacement-bursts at constant load in a nanoindentation test, are typically attributed to the difficulty of setting up potent dislocation sources in the very small indentation zones in these experiments. Such displacement (and strain) bursts would intuitively indicate a sharp drop in stress during the pop-in event itself. However, spherical indentation stress-strain curves routinely exhibit a high and stable indentation stress value during the pop-in, and the indentation stresses decrease only after a further finite amount of additional indentation displacement has been applied. In order to understand this discrepancy, we utilize a combination of interrupted spherical indentation tests along with depth profiling of the residual indentation surfaces using in-situ atomic force microscopy (AFM) to study pop-ins. The AFM surface profile maps show that there is an asymmetric profile change over a limited region around the indentation contact area for a single pop-in; the asymmetry disappears upon further loading beyond the pop-in. A plausible sequence of physical processes (related to metal plasticity) occurring underneath the indenter during and immediately after the occurrence of the pop-in is proposed to explain these observations.

  8. Determination of Young's modulus by nanoindentation

    Institute of Scientific and Technical Information of China (English)

    MA Dejun; Chung Wo Ong; LIU Jianmin; HE Jiawen

    2004-01-01

    A methodology for determining Young's modulus of materials by non-ideally sharp indentation has been developed. According to the principle of the same area-to-depth ratio, a non-ideally pyramidal indenter like a Berkovich one can be approximated by a non-ideally conical indenter with a spherical cap at the tip. By applying dimensional and finite element analysis to the non-ideally conical indentation, a set of approximate one-to-one relationships between the ratio of nominal hardness/reduced Young's modulus and the ratio of elastic work/total work, which correspond to different tip bluntness, have been revealed. The nominal hardness is defined as the maximum indentation load divided by the cross-section area of the conical indenter specified at the maximum indentation depth. As a consequence, Young's modulus can be determined from a nanoindentation test only using the maximum indentation load and depth, and the work done during loading and unloading processes. The new method for determining Young's modulus is referred to as "pure energy method". The validity of the method was examined by performing indentation tests on five materials. The experimental results and the standard reference values are in good agreement, indicating that the proposed pure energy method is a promising substitution for the most widely used analysis models at present.

  9. Nanoindentation of Electropolished FeCrAl Alloy Welds

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, Jordan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Aydogan, Eda [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mara, Nathan Allan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Maloy, Stuart Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-13

    The present report summarizes Berkovich nanoindentation modulus and hardness measurements on two candidate FeCrAl alloys (C35M and C37M) on as-received (AR) and welded samples. In addition, spherical nanoindentation stress-strain measurements were performed on individual grains to provide further information and demonstrate the applicability of these protocols to mechanically characterizing welds in FeCrAl alloys. The indentation results are compared against the reported tensile properties for these alloys to provide relationships between nanoindentation and tensile tests and insight into weldsoftening for these FeCrAl alloys. Hardness measurements revealed weld-softening for both alloys in good agreement with tensile test results. C35M showed a larger reduction in hardness at the weld center from the AR material compared to C37M; this is also consistent with tensile tests. In general, nanohardness was shown to be a good predictor of tensile yield strength and ultimate tensile stress for FeCrAl alloys. Spherical nanoindentation measurements revealed that the fusion zone (FZ) + heat affected zone (HAZ) has a very low defect density typical of well-annealed metals as indicated by the frequent pop-in events. Spherical nanoindentation yield strength, Berkovich hardness, and tensile yield strength measurements on the welded material all show that the C37M welded material has a higher strength than C35M welded material. From the comparison of nanoindentation and tensile tests, EBSD microstructure analysis, and information on the processing history, it can be deduced that the primary driver for weld-softening is a change in the defect structure at the grain-scale between the AR and welded material. These measurements serve as baseline data for utilizing nanoindentation for studying the effects of radiation damage on these alloys.

  10. Manipulator for rotating and translating a sample holder

    Science.gov (United States)

    van de Water, Jeroen; van den Oetelaar, Johannes; Wagner, Raymond; Slingerland, Hendrik Nicolaas; Bruggers, Jan Willem; Ottevanger, Adriaan Huibert Dirk; Schmid, Andreas; Olson, Eric A.; Petrov, Ivan G.; Donchev, Todor I.; Duden, Thomas

    2011-02-08

    A manipulator for use in e.g. a Transmission Electron Microscope (TEM) is described, said manipulator capable of rotating and translating a sample holder (4). The manipulator clasps the round sample holder between two members (3A, 3B), said members mounted on actuators (2A, 2B). Moving the actuators in the same direction results in a translation of the sample holder, while moving the actuators in opposite directions results in a rotation of the sample holder.

  11. Lexan Linear Shaped Charge Holder with Magnets and Backing Plate

    Science.gov (United States)

    Maples, Matthew W.; Dutton, Maureen L.; Hacker, Scott C.; Dean, Richard J.; Kidd, Nicholas; Long, Chris; Hicks, Robert C.

    2013-01-01

    A method was developed for cutting a fabric structural member in an inflatable module, without damaging the internal structure of the module, using linear shaped charge. Lexan and magnets are used in a charge holder to precisely position the linear shaped charge over the desired cut area. Two types of charge holders have been designed, each with its own backing plate. One holder cuts fabric straps in the vertical configuration, and the other charge holder cuts fabric straps in the horizontal configuration.

  12. 7 CFR 1463.107 - Payment to eligible quota holders.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Payment to eligible quota holders. 1463.107 Section... PROGRAM Tobacco Transition Payment Program § 1463.107 Payment to eligible quota holders. (a) The total amount of contract payments that may be made to an eligible quota holder shall be the product obtained...

  13. 21 CFR 880.5680 - Pediatric position holder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pediatric position holder. 880.5680 Section 880.5680 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Devices § 880.5680 Pediatric position holder. (a) Identification. A pediatric position holder is a...

  14. 21 CFR 892.1920 - Radiographic head holder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic head holder. 892.1920 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1920 Radiographic head holder. (a) Identification. A radiographic head holder is a device intended to position the patient's head during...

  15. 7 CFR 1463.103 - Eligible quota holder.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Eligible quota holder. 1463.103 Section 1463.103... Transition Payment Program § 1463.103 Eligible quota holder. (a) CCC will make a payment under this subpart to a person determined by CCC to be an eligible quota holder, as defined in § 1463.102. (b)...

  16. 14 CFR 21.165 - Responsibility of holder.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Responsibility of holder. 21.165 Section 21... CERTIFICATION PROCEDURES FOR PRODUCTS AND PARTS Production Certificates § 21.165 Responsibility of holder. The holder of a production certificate shall— (a) Maintain the quality control system in conformity with...

  17. 14 CFR 21.316 - Responsibility of holder.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Responsibility of holder. 21.316 Section 21.316 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Responsibility of holder. Each holder of a PMA must— (a) Amend the document required by § 21.305 as necessary...

  18. 21 CFR 882.4460 - Neurosurgical head holder (skull clamp).

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Neurosurgical head holder (skull clamp). 882.4460 Section 882.4460 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... holder (skull clamp). (a) Identification. A neurosurgical head holder (skull clamp) is a device used...

  19. 10 CFR 72.160 - Licensee and certificate holder inspection.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Licensee and certificate holder inspection. 72.160 Section... WASTE Quality Assurance § 72.160 Licensee and certificate holder inspection. The licensee, applicant for a license, certificate holder, and applicant for a CoC shall establish and execute a program...

  20. 7 CFR 4280.137 - Repurchase from holder.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Repurchase from holder. 4280.137 Section 4280.137... Efficiency Improvements Program Section B. Guaranteed Loans § 4280.137 Repurchase from holder. Any repurchase from a holder must be in accordance with § 4279.78 of this chapter....

  1. 14 CFR 125.243 - Certificate holder's responsibilities.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Certificate holder's responsibilities. 125... Certificate holder's responsibilities. (a) With regard to airplanes, including airframes, aircraft engines, propellers, appliances, and survival and emergency equipment, operated by a certificate holder,...

  2. 21 CFR 870.3935 - Prosthetic heart valve holder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Prosthetic heart valve holder. 870.3935 Section 870.3935 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... heart valve holder. (a) Identification. A prosthetic heart valve holder is a device used to hold...

  3. Zaria Universal Oxygenator Holder phase I

    Directory of Open Access Journals (Sweden)

    Sunday Adoga Edaigbini

    2014-01-01

    Full Text Available Introduction: The conduct of cardiopulmonary bypass surgery requires the use of equipment and devices like the oxygenator. The oxygenator comes in different makes and each manufacturer customizes the carrier or ′holder′ of this device specific to their design. Aim: This paper presents an innovation designed to overcome the need to purchase a different holder for every oxygenator thereby cutting the cost. Materials and Methods: A sheet of iron measuring 1.9 cm (width × 0.1 cm (thickness was used to design the holder circular main frame. Another sheet measuring 2 cm (width × 0.6 cm (thickness × 24 cm (length was used to construct a V-shaped handle with the arms of the V attached to the main frame 7 cm apart. At the narrow base of the handle is a latch requiring two 13-gauge screws to attach the holder to the heart-lung machine. Within the circumference of the main frame are four T-shaped side arms which grip the oxygenator; located at 2, 5, 7 and 11 O′clock positions. The stem of the T consist of a 0.6 cm (thickness × 13 cm (length rod drilled through the main frame. The cross of the T consists of variable lengths of the same sheet as the mainframe attached to the stem by a screw mechanism. At the base of the T, is attached a circular handle (4 cm in diameter made of 0.4 cm iron rod. Result: An oxygenator holder which weighs 1.75 kg with a total length of 54 cm (the diameter of the mainframe is 30 cm. Its advantages include (i affordability, (ii materials are locally accessible, (iii versatility (iv reproducibility. The disadvantages include, (i it requires some time to fit, (ii caution is required in fitting the oxygenator to avoid breakage, (iii a spanner is required to lock the latch. Conclusion: The concept of a universal holder is pertinent, especially in resource poor environments to avoid purchasing a new holder whenever the usual oxygenator common to the centre is unavailable. This device is amenable to further modifications to

  4. The evolution of machining-induced surface of single-crystal FCC copper via nanoindentation.

    Science.gov (United States)

    Zhang, Lin; Huang, Hu; Zhao, Hongwei; Ma, Zhichao; Yang, Yihan; Hu, Xiaoli

    2013-05-04

    The physical properties of the machining-induced new surface depend on the performance of the initial defect surface and deformed layer in the subsurface of the bulk material. In this paper, three-dimensional molecular dynamics simulations of nanoindentation are preformed on the single-point diamond turning surface of single-crystal copper comparing with that of pristine single-crystal face-centered cubic copper. The simulation results indicate that the nucleation of dislocations in the nanoindentation test on the machining-induced surface and pristine single-crystal copper is different. The dislocation embryos are gradually developed from the sites of homogeneous random nucleation around the indenter in the pristine single-crystal specimen, while the dislocation embryos derived from the vacancy-related defects are distributed in the damage layer of the subsurface beneath the machining-induced surface. The results show that the hardness of the machining-induced surface is softer than that of pristine single-crystal copper. Then, the nanocutting simulations are performed along different crystal orientations on the same crystal surface. It is shown that the crystal orientation directly influences the dislocation formation and distribution of the machining-induced surface. The crystal orientation of nanocutting is further verified to affect both residual defect generations and their propagation directions which are important in assessing the change of mechanical properties, such as hardness and Young's modulus, after nanocutting process.

  5. Moment Inequality and Holder Inequality for BSDEs

    Institute of Scientific and Technical Information of China (English)

    Sheng-jun Fan

    2009-01-01

    Under the Lipschitz and square integrable assumptions on the generator g of BSDEs,this paper proves that if g is positively homogeneous in(y,z)and is decreasing in y,then the Moment inequality for BSDEs with generator g holds in general,and if g is positively homogeneous and sub-additive in(y,z),then the Holder inequality and Minkowski inequality for BSDEs with generator g hold in general.

  6. Sample holder for X-ray diffractometry

    Science.gov (United States)

    Hesch, Victor L.

    1992-01-01

    A sample holder for use with X-ray diffractometers with the capability to rotate the sample, as well as to adjust the position of the sample in the x, y, and z directions. Adjustment in the x direction is accomplished through loosening set screws, moving a platform, and retightening the set screws. Motion translators are used for adjustment in the y and z directions. An electric motor rotates the sample, and receives power from the diffractometer.

  7. Non-contemporaneous variations and Holder's principle

    Institute of Scientific and Technical Information of China (English)

    LIANG; Lifu(梁立孚); HU; Haichang; (胡海昌); LIU; Shiquan; (刘石泉)

    2003-01-01

    In the process of deducing the Holder principle, a key step is to use the concept of non-contemporaneous variations. In this paper, whether starting from analytic method or from graphic solution method, the authors prove that the expression formula of non-contemporaneous variations is incorrect when the variable functions have zero-order nearness degree, and obtain a new expression. From the view of calculus of variations and differential calculus, the non-contemporaneous variations are studied. The study result shows that the concept of non-contemporaneous variations is a combination of the concept of variations and the concept of differentiation. The authors prove that the new expression is correct and obtain an equivalent expression of it. By means of this equivalent expression, this paper proves that the above expression formula of non-contemporaneous variations is correct when the variable functions have one-order nearness degree. Further study shows that, in the process of deducing Holder's principle, there is an implicit expression. Whether starting from analytic method or from graphic solution method, the authors discovered that the implicit expression of non-contemporaneous variations is incorrect when the variable functions have zero-order nearness degree and have one-order nearness degree. This paper proves that the implicit expression of non-contemporaneous variations is correct when the variable functions have two-order nearness degree. Further study shows that Holder's principle is tenable when the variable functions have two-order nearness degree.

  8. Implementation of a Light Source in a TEM Sample Holder for In-situ Studies of Photocatalytic Materials

    DEFF Research Database (Denmark)

    Cavalca, Filippo; Hansen, Thomas Willum; Wagner, Jakob Birkedal

    constructed a specimen holder capable of shining light onto samples inside the TEM. The holder contains a laser diode and an optical system that guides light onto a sample with maximum power transmission. The source can be changed and tuned, in principle spanning the whole visible and UV spectrum. The device...... metal nanoparticle photodeposition, light-driven particle discharging and photodegradation. We concentrate on phase transitions of Cu2O nanocubes under visible light exposure in the presence of water vapor, which we study in situ. Cu2O is an active photocatalyst for water splitting under visible light...

  9. Tomographic heating holder for in situ TEM: study of Pt/C and PtPd/Al2O3 catalysts as a function of temperature.

    Science.gov (United States)

    Gontard, Lionel C; Dunin-Borkowski, Rafal E; Fernández, Asunción; Ozkaya, Dogan; Kasama, Takeshi

    2014-06-01

    A tomographic heating holder for transmission electron microscopy that can be used to study supported catalysts at temperatures of up to ~1,500°C is described. The specimen is placed in direct thermal contact with a tungsten filament that is oriented perpendicular to the axis of the holder without using a support film, allowing tomographic image acquisition at high specimen tilt angles with minimum optical shadowing. We use the holder to illustrate the evolution of the active phases of Pt nanoparticles on carbon black and PtPd nanoparticles on γ-alumina with temperature. Particle size distributions and changes in active surface area are quantified from tilt series of images acquired after subjecting the specimens to increasing temperatures. The porosity of the alumina support and the sintering mechanisms of the catalysts are shown to depend on distance from the heating filament.

  10. In situ nanoindentation in a transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Minor, Andrew M. [Univ. of California, Berkeley, CA (United States)

    2002-01-01

    This dissertation presents the development of the novel mechanical testing technique of in situ nanoindentation in a transmission electron microscope (TEM). This technique makes it possible to simultaneously observe and quantify the mechanical behavior of nano-scale volumes of solids.

  11. Serrated plastic flow during nanoindentation of a bulk metallic glass

    NARCIS (Netherlands)

    Golovin, YI; Ivolgin, [No Value; Khonik, VA; Kitagawa, K; Tyurin, AI

    2001-01-01

    The results of nanoindentation tests of bulk glassy Pd40CU30Ni10P20 using a specially designed instrument with high time and spatial resolution are presented. Pronounced serrations of the indenter penetration depth are observed. The parameters of serrated flow (the number of serrations, their amplit

  12. Thermomechanical Characterization of Shape Memory Polymers using High Temperature Nanoindentation

    Science.gov (United States)

    2010-01-01

    spherical indenter with a tip radius of 100 mmwas used in the present experiments. The latest tips provided by the manufacturer had all been brazed onto the...Nanoindentation of Au and Pt/ Cu thin films at elevated temperatures. J. Mater. Res. 19 (9) (2004) 2650–2657. [19] A. Sawant, S. Tin, High temperature

  13. An international round-robin calibration protocol for nanoindentation measurements.

    Science.gov (United States)

    Cabibbo, M; Ricci, P; Cecchini, R; Rymuza, Z; Sullivan, J; Dub, S; Cohen, S

    2012-02-01

    Nanoindentation has become a common technique for measuring the hardness and elastic-plastic properties of materials, including coatings and thin films. In recent years, different nanoindenter instruments have been commercialised and used for this purpose. Each instrument is equipped with its own analysis software for the derivation of the hardness and reduced Young's modulus from the raw data. These data are mostly analysed through the Oliver and Pharr method. In all cases, the calibration of compliance and area function is mandatory. The present work illustrates and describes a calibration procedure and an approach to raw data analysis carried out for six different nanoindentation instruments through several round-robin experiments. Three different indenters were used, Berkovich, cube corner, spherical, and three standardised reference samples were chosen, hard fused quartz, soft polycarbonate, and sapphire. It was clearly shown that the use of these common procedures consistently limited the hardness and reduced the Young's modulus data spread compared to the same measurements performed using instrument-specific procedures. The following recommendations for nanoindentation calibration must be followed: (a) use only sharp indenters, (b) set an upper cut-off value for the penetration depth below which measurements must be considered unreliable, (c) perform nanoindentation measurements with limited thermal drift, (d) ensure that the load-displacement curves are as smooth as possible, (e) perform stiffness measurements specific to each instrument/indenter couple, (f) use Fq and Sa as calibration reference samples for stiffness and area function determination, (g) use a function, rather than a single value, for the stiffness and (h) adopt a unique protocol and software for raw data analysis in order to limit the data spread related to the instruments (i.e. the level of drift or noise, defects of a given probe) and to make the H and E(r) data intercomparable.

  14. Effect of blank holder pressure on viscous pressure forming aluminum alloy ladder parts

    Institute of Scientific and Technical Information of China (English)

    王忠金; 王新云; 王仲仁

    2002-01-01

    Viscous pressure forming (VPF), is suitable for forming difficult-to-form sheet metal parts. An investigation in the effect of blank holder pressure (BHP) on VPF aluminum alloy ladder parts was conducted. Based on experimental and numerical simulation results of the effect of BHP on dimensional accuracy, wall-thickness reduction, forming pressure, material flow and defects (such as wrinkling and fracture) of specimens, the effect patterns of BHP load path on VPF ladder parts were explained. The limits of BHP corresponding to specimens with no defect and with wrinkling or fracture defect were determined. In the limits of formable BHP, the variable load path of BHP was beneficial to drawing blank into the die and decreasing wall-thickness reduction of specimens. The experimental results show that the ladder parts of good surface fineness and high dimensional accuracy can be obtained by variable load paths of BHP.

  15. Urine culture - catheterized specimen

    Science.gov (United States)

    Culture - urine - catheterized specimen; Urine culture - catheterization; Catheterized urine specimen culture ... urinary tract infections may be found in the culture. This is called a contaminant. You may not ...

  16. 75 FR 59711 - Audit Program for Texas Flexible Permit Holders

    Science.gov (United States)

    2010-09-28

    ... waiver of the gravity component of any penalties resulting from noncompliance uncovered by the Audit... on the Audit Program for Texas flexible permit holders, please contact Mr. John Jones, Air...). EPA is proposing the Audit Program as a mechanism for Texas Flexible Permit holders to transition...

  17. 38 CFR 36.4278 - Servicing procedures for holders.

    Science.gov (United States)

    2010-07-01

    ... evaluation of delinquency and foreclosure rates on loans in its portfolio which are guaranteed by the Secretary. As part of its evaluation of delinquency and foreclosure rates, the holder shall: (1) Collect and... such efforts and the holder's evaluation of the reason for the default and prospects for resolution...

  18. Filter holder assembly having extended collar spacer ring

    Science.gov (United States)

    Alvin, Mary Anne; Bruck, Gerald J.

    2002-01-01

    A filter holder assembly is provided that utilizes a fail-safe regenerator unit with an annular spacer ring having an extended metal collar for containment and positioning of a compliant ceramic gasket used in the assembly. The filter holder assembly is disclosed for use with advanced composite, filament wound, and metal candle filters.

  19. 32 CFR 2001.41 - Responsibilities of holders.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Responsibilities of holders. 2001.41 Section 2001.41 National Defense Other Regulations Relating to National Defense INFORMATION SECURITY OVERSIGHT... Safeguarding § 2001.41 Responsibilities of holders. Authorized persons who have access to...

  20. Filter holder and gasket assembly for candle or tube filters

    Science.gov (United States)

    Lippert, Thomas Edwin; Alvin, Mary Anne; Bruck, Gerald Joseph; Smeltzer, Eugene E.

    1999-03-02

    A filter holder and gasket assembly for holding a candle filter element within a hot gas cleanup system pressure vessel. The filter holder and gasket assembly includes a filter housing, an annular spacer ring securely attached within the filter housing, a gasket sock, a top gasket, a middle gasket and a cast nut.

  1. Invited Article: Indenter materials for high temperature nanoindentation.

    Science.gov (United States)

    Wheeler, J M; Michler, J

    2013-10-01

    As nanoindentation at high temperatures becomes increasingly popular, a review of indenter materials for usage at high temperatures is instructive for identifying appropriate indenter-sample materials combinations to prevent indenter loss or failure due to chemical reactions or wear during indentation. This is an important consideration for nanoindentation as extremely small volumes of reacted indenter material will have a significant effect on measurements. The high temperature hardness, elastic modulus, thermal properties, and chemical reactivities of diamond, boron carbide, silicon carbide, tungsten carbide, cubic boron nitride, and sapphire are discussed. Diamond and boron carbide show the best elevated temperature hardness, while tungsten carbide demonstrates the lowest chemical reactivity with the widest array of elements.

  2. Transmission electron microscope sample holder with optical features

    Science.gov (United States)

    Milas, Mirko [Port Jefferson, NY; Zhu, Yimei [Stony Brook, NY; Rameau, Jonathan David [Coram, NY

    2012-03-27

    A sample holder for holding a sample to be observed for research purposes, particularly in a transmission electron microscope (TEM), generally includes an external alignment part for directing a light beam in a predetermined beam direction, a sample holder body in optical communication with the external alignment part and a sample support member disposed at a distal end of the sample holder body opposite the external alignment part for holding a sample to be analyzed. The sample holder body defines an internal conduit for the light beam and the sample support member includes a light beam positioner for directing the light beam between the sample holder body and the sample held by the sample support member.

  3. Thin film adhesion by nanoindentation-induced superlayers. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Gerberich, William W.; Volinsky, A.A.

    2001-06-01

    This work has analyzed the key variables of indentation tip radius, contact radius, delamination radius, residual stress and superlayer/film/interlayer properties on nanoindentation measurements of adhesion. The goal to connect practical works of adhesion for very thin films to true works of adhesion has been achieved. A review of this work titled ''Interfacial toughness measurements of thin metal films,'' which has been submitted to Acta Materialia, is included.

  4. Nanoindentation investigation of creep properties of calcium silicate hydrates

    OpenAIRE

    Vandamme, Matthieu; ULM, Franz Josef

    2013-01-01

    The creep properties of calcium silicate hydrates (C-S-H) are assessed by means of nanoindentation creep experiments on a wide range of substoichiometric cement pastes. We observe that, after a few seconds, the measured creep compliance of C-S-H is very well captured by a logarithmic time function. The rate of the logarithmic creep is found to scale in a unique manner with indentation modulus, indentation hardness, and packing density, independent of processing, mix proportions, indenter geom...

  5. Nanoindentation hardness and elastic modulus of nano-grained titanium produced by asymmetric and symmetric rolling.

    Science.gov (United States)

    Li, Zhiming; Fu, Liming; Fu, Bin; Yang, Xiaoping; Shan, Aidang

    2014-10-01

    To understand the nanomechanical properties of nano-grained (NG) Ti produced by combination of asymmetric and symmetric rolling, nanoindentation hardness (H(n)) and elastic modulus (E(n)) of different planes within the NG Ti specimens were measured using continuous stiffness measurement mode at room temperature. For comparison, the nanomechanical properties of the as-received hot-rolled coarse-grained (CG) Ti and ultrafine-grained (UFG) Ti with only asymmetric rolling process were also investigated. It was found that H(n) of the Ti samples increased significantly with the decrease of grain sizes, while E(n) exhibited a slight decrease as the grain sizes decreased from CG to NG regime. The increase of H(n) was expected to be caused by higher density of dislocations and finer grains attained by severer plastic deformation, while the slight decrease of E(n) was considered as a result of the increased density of lattice defects and volume fraction of the grain boundary atoms. Furthermore, the nanomechanical properties of different planes of the Ti specimen exhibited a little difference which can be expressed as H(n(RD-TD)) > H(n(N-RD)) > H(n(TD-ND)) and E(n(RD-TD)) > E(n(ND-RD)) > E(n(TD-ND)). These differences were ascribed to crystallographic textures formed by rolling deformation.

  6. Comparison of dentin hardness between conventional drill and chemomechanical methods in primary and permanent dentition using nanoindenter

    Directory of Open Access Journals (Sweden)

    M Kruthika

    2016-01-01

    Full Text Available Introduction: Latest theories regarding the rationale of carious dentin removal are beginning to question the amount of tissue that needs to be excavated to successfully treat a carious tooth. It is not always easy to make a decision at which point to stop excavation because there is an apparent lack of objective clinical markers. However, hardness of dentin might be a useful marker in this respect. Nanoindentation test is a variety of indentation hardness test applied to small volumes such as teeth which contain nanosized structures. Aims: To compare and evaluate the nanohardness of dentin after chemomechanical (Carie-care method of caries removal with the conventional (rotary instrument method of caries removal in primary and permanent teeth using nanoindenter. Materials and Methods: An in vitro randomized controlled trial was conducted using fifteen primary and fifteen permanent extracted molars with active carious lesion extending into the dentin. The primary and permanent molars were further randomly divided into two subgroups by sectioning the samples into two halves. Caries removal was done using conventional drill (CD and chemomechanical caries removal (CMCR (Carie-care methods. Following the caries removal, the test specimens were subjected for evaluation of nanohardness of dentin using nanoindenter. Student's t-test, analysis of variance, and Bonferroni test were used. Results: Statistically significant difference between the 4 groups with a P < 0.05 was obtained. Conclusions: After caries removal, the hardness of remaining dentin was found to be harder after CMCR method than with the CD method in both primary and permanent teeth, and the remaining dentin of the permanent teeth was found to be harder than the primary teeth after caries removal.

  7. Practical aspects of the use of the X(2) holder for HRTEM-quality TEM sample preparation by FIB.

    Science.gov (United States)

    van Mierlo, Willem; Geiger, Dorin; Robins, Alan; Stumpf, Matthias; Ray, Mary Louise; Fischione, Paul; Kaiser, Ute

    2014-12-01

    The X(2) holder enables the effective production of thin, electron transparent samples for high-resolution transmission electron microscopy (HRTEM). Improvements to the X(2) holder for high-quality transmission electron microscopy (TEM) sample preparation are presented in this paper. We discuss the influence of backscattered electrons (BSE) from the sample holder in determining the lamella thickness in situ and demonstrate that a significant improvement in thickness determination can be achieved by comparatively simple means using the relative BSE intensity. We show (using Monte Carlo simulations) that by taking into account the finite collection angle of the electron backscatter detector, an approximately 20% underestimation of the lamella thickness in a silicon sample can be avoided. However, a correct thickness determination for light-element lamellas still remains a problem with the backscatter method; we introduce a more accurate method using the energy dispersive X-ray spectroscopy (EDX) signal for in situ thickness determination. Finally, we demonstrate how to produce a thin lamella with a nearly damage-free surface using the X(2) holder in combination with sub-kV polishing in the Fischione Instruments׳ NanoMill(®) TEM specimen preparation system.

  8. Darfur and the flaws of Holder v HLP

    Directory of Open Access Journals (Sweden)

    Christopher Thornton

    2011-03-01

    Full Text Available When US Chief Justice Roberts handed down the judgment in Holder v Humanitarian Law Project, he revealed the Supreme Court’s tragic under-estimation of the potential of engagement with non-state armed groups....

  9. Cryogel micromechanics unraveled by atomic force microscopy-based nanoindentation.

    Science.gov (United States)

    Welzel, Petra B; Friedrichs, Jens; Grimmer, Milauscha; Vogler, Steffen; Freudenberg, Uwe; Werner, Carsten

    2014-11-01

    Cell-instructive physical characteristics of macroporous scaffolds, developed for tissue engineering applications, often remain difficult to assess. Here, an atomic force microscopy-based nanoindentation approach is adapted to quantify the local mechanical properties of biohybrid glycosaminoglycan-poly(ethylene glycol) cryogels. Resulting from cryoconcentration effects upon gel formation, cryogel struts are observed to feature a higher stiffness compared to the corresponding bulk hydrogel materials. Local Young's moduli, porosity, and integral moduli of the cryogel scaffolds are compared in dependence on gel formation parameters. The results provide valuable insights into the cryogelation process and a base for adjusting physical characteristics of the obtained cryogel scaffolds, which can critically influence the cellular response.

  10. Theoretical modeling developed to evaluate the hardness and reduced modulus for the C/a-Si composite film using nanoindentation tests.

    Science.gov (United States)

    Han, Chang-Fu; Wu, Bo-Hsiung; Lin, Jen-Fin; Chung, Chen-Kuei

    2008-08-13

    A general mechanical model, which is composed of the mechanical models employed to describe the contact behaviors and deformations arising in all layers (including the substrate), is successfully developed in the present study for multilayer specimens in order to evaluate the contact projected area by a theoretical model, and thus the hardness and reduced modulus, using nanoindentation tests. The governing differential equations for the depth solutions of the indenter tip formed at all layers of the specimen under their contact load are developed individually. The influence of the material properties of the substrate on a multilayer specimen's hardness and reduced modulus at various indentation depths can thus be evaluated. Transition and pop-in occurred at depths near, but still before, the C (top layer)/a-Si (buffer layer) interface and the a-Si/Si (substrate) interface, respectively. Using the present analysis, the depths corresponding to the transition and pop-in behaviors can be predicted effectively.

  11. 10 CFR 39.43 - Inspection, maintenance, and opening of a source or source holder.

    Science.gov (United States)

    2010-01-01

    ... holder. 39.43 Section 39.43 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY... holder. (a) Each licensee shall visually check source holders, logging tools, and source handling tools... holders, logging tools, injection tools, source handling tools, storage containers, transport...

  12. 49 CFR 192.175 - Pipe-type and bottle-type holders.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Pipe-type and bottle-type holders. 192.175 Section....175 Pipe-type and bottle-type holders. (a) Each pipe-type and bottle-type holder must be designed so as to prevent the accumulation of liquids in the holder, in connecting pipe, or in...

  13. 46 CFR 10.233 - Obligations of the holder of a merchant mariner credential.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Obligations of the holder of a merchant mariner... § 10.233 Obligations of the holder of a merchant mariner credential. (a) The holder of a credential may... credential. If the holder violates this section, the Coast Guard may pursue suspension or revocation of...

  14. 7 CFR 762.144 - Repurchase of guaranteed portion from a secondary market holder.

    Science.gov (United States)

    2010-01-01

    ... market holder. 762.144 Section 762.144 Agriculture Regulations of the Department of Agriculture... Repurchase of guaranteed portion from a secondary market holder. (a) Request for repurchase. The holder may... failed to remit to the holder its pro-rata share of any payment made by the borrower within 30 days...

  15. 42 CFR 60.31 - The application to be a HEAL lender or holder.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false The application to be a HEAL lender or holder. 60... HEALTH EDUCATION ASSISTANCE LOAN PROGRAM The Lender and Holder § 60.31 The application to be a HEAL lender or holder. (a) In order to be a HEAL lender or holder, an eligible organization must submit...

  16. 42 CFR 60.32 - The HEAL lender or holder insurance contract.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false The HEAL lender or holder insurance contract. 60.32... EDUCATION ASSISTANCE LOAN PROGRAM The Lender and Holder § 60.32 The HEAL lender or holder insurance contract. (a)(1) If the Secretary approves an application to be a HEAL lender or holder, the Secretary and...

  17. Multi-field nanoindentation apparatus for measuring local mechanical properties of materials in external magnetic and electric fields

    CERN Document Server

    Zhou, Hao; Huang, Hu; Zhao, Hongwei; Li, Faxin; Fang, Daining

    2013-01-01

    Nano/micro-scale mechanical properties of multiferroic materials can be controlled by the external magnetic or electric field due to the coupling interaction. For the first time, a modularized multi-field nanoindentation apparatus for carrying out testing on materials in external magnetostatic/electrostatic field is constructed. Technical issues, such as the application of magnetic/electric field and the processes to diminish the interference between external fields and the other parts of the apparatus, are addressed. Tests on calibration specimen indicate the feasibility of the apparatus. The load-displacement curves of ferromagnetic, ferroelectric and magnetoelectric materials in the presence/absence of external fields reveal the small-scale magnetomechanical and electromechanical coupling, showing as the Delta-E and Delta-H effects, i.e. the magnetic/electric field induced changes in the apparent elastic modulus and indentation hardness.

  18. Cross-Sectional Residual Stresses in Thermal Spray Coatings Measured by Moiré Interferometry and Nanoindentation Technique

    Science.gov (United States)

    Zhu, Jianguo; Xie, Huimin; Hu, Zhenxing; Chen, Pengwan; Zhang, Qingming

    2012-09-01

    A plasma-sprayed thermal barrier coating (TBC) was deposited on a stainless steel substrate. The residual stresses were firstly measured by moiré interferometry combined with a cutting relaxation method. The fringe patterns in the cross-section of the specimen clearly demonstrate the deformation caused by the residual stress in thermal spray coatings. However, restricted by the sensitivity of moiré interferometry, there are few fringes in the top coat, and large errors may exist in evaluating the residual stress in the top coat. Then, the nanoindentation technique was used to estimate the residual stresses across the coating thickness. The stress/depth profile shows that the process-induced stresses after thermal spray are compressive in the top coat and a tendency to a more compressive state toward the interface. In addition, the stress gradient in the substrate is nonlinear, and tensile and compressive stresses appear simultaneously for self-equilibrium in the cross-section.

  19. WRINKLE LIMIT BLANK HOLDER FORCE MODELS IN SQUARE-BOX DEEP DRAWING WITH VARIABLE SEGMENT BLANK-HOLDERS

    Institute of Scientific and Technical Information of China (English)

    LEI Kun; ZHANG Kaifeng; WANG Zhongqi

    2006-01-01

    Constituting the reasonable control models of the wrinkle limit blank holder forces is the sticking point of the processes of the deep drawing with variable blank-holder forces, especially in the square-box forming. To begin with, a mode of segmenting flange of the square-box into eight zones is put forward according to the fact that the uniformity of flange deforming can be improved by controlling segment blank-holders. Considering the integral influence of shear stress, a new concept, strain relaxation factor is defined. Hereby, the law of distribution of stress and stain in the deforming flange of square-box is achieved. Then based on these mechanical analysis models and the energy principle,the wrinkling flexivity functions of the straight flange and the circle flange are given, and the corresponding formulae of wrinkling limit blank-holder force in these two situations are also educed. In these processes, ply-anisotropy, strain hardening, thickness and friction are considered. In the end, a calculating example is designed to validate the rationality of the formulae of wrinkling limit blank-holder force, at the same time, the influences of the ply-anisotropy exponent and the strain hardening exponent on the wrinkle limit blank holder forces are also analyzed.

  20. Berkovich Nanoindentation on AlN Thin Films

    Directory of Open Access Journals (Sweden)

    Jian Sheng-Rui

    2010-01-01

    Full Text Available Abstract Berkovich nanoindentation-induced mechanical deformation mechanisms of AlN thin films have been investigated by using atomic force microscopy (AFM and cross-sectional transmission electron microscopy (XTEM techniques. AlN thin films are deposited on the metal-organic chemical-vapor deposition (MOCVD derived Si-doped (2 × 1017 cm−3 GaN template by using the helicon sputtering system. The XTEM samples were prepared by means of focused ion beam (FIB milling to accurately position the cross-section of the nanoindented area. The hardness and Young’s modulus of AlN thin films were measured by a Berkovich nanoindenter operated with the continuous contact stiffness measurements (CSM option. The obtained values of the hardness and Young’s modulus are 22 and 332 GPa, respectively. The XTEM images taken in the vicinity regions just underneath the indenter tip revealed that the multiple “pop-ins” observed in the load–displacement curve during loading are due primarily to the activities of dislocation nucleation and propagation. The absence of discontinuities in the unloading segments of load–displacement curve suggests that no pressure-induced phase transition was involved. Results obtained in this study may also have technological implications for estimating possible mechanical damages induced by the fabrication processes of making the AlN-based devices.

  1. Nano-indentation of Polycarbonate and Diamine Blends

    Science.gov (United States)

    Ahuja, Suresh

    2012-02-01

    Nanoindentation of complex surfaces is of great interest from academic and industrial point of view. There are unique properties such as indentation effects resulting in strain softening and strain hardening. There is a differentiation in structure with the depth exhibited with variation of Tg. Hertzian and non-linear deformation models including usage of FEM offer opportunity in analyzing nano-indentation. In polycarbonate, the effective elastic modulus and the hardness decreases as the applied load is increased. As the hold time was increased, the effective elastic modulus and the hardness also decreased. The contact stress increases as the contact strain rate is increased. Presence of diamine(MTBD) in polycarbonate results in making the surface and bulk brittle and acts as an anti-plasticizer by increasing it modulus and reducing yield stress (hardness) and strain to break. Data on modulus and hardness of polycarbonate and blends of diamine as function of depth (strain) and strain rate are presented and compared with those of composites with silica.

  2. New Insights into Nanoindentation-Based Adhesion Testing

    Science.gov (United States)

    Kleinbichler, A.; Pfeifenberger, M. J.; Zechner, J.; Moody, N. R.; Bahr, D. F.; Cordill, M. J.

    2017-08-01

    Nanoindentation, or instrumented indentation, is a versatile technique that is most often used to measure the elastic modulus and hardness of thin film systems. It can also be employed to measure thin film adhesion energies by producing well-defined areas of delamination. When combined with the proper mechanics-based model and characterization of the failing interfaces, nanoindentation-induced delamination is a powerful tool to quantify interfacial fracture. This article highlights new improvements to the technique that build off the work of Marshall and Evans in the 1980s. Indentation-induced delamination in systems with brittle films or substrates can be a balance between causing delamination and causing through-thickness or bulk fracture. Focused ion beam cross-sectioning and confocal laser scanning microscopy were used to characterize failing interfaces, additional fracture events were observed in the load-displacement curves, and the adhesion energy was determined using not only symmetric, ideally shaped buckles, but also irregular-shaped and half-delaminated buckles.

  3. 37 CFR 2.59 - Filing substitute specimen(s).

    Science.gov (United States)

    2010-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Filing substitute specimen(s..., DEPARTMENT OF COMMERCE RULES OF PRACTICE IN TRADEMARK CASES Drawing § 2.59 Filing substitute specimen(s). (a... specimen(s), the applicant must: (1) For an amendment to allege use under § 2.76, verify by affidavit...

  4. Correction of the post -- necking true stress -- strain data using instrumented nanoindentation

    Science.gov (United States)

    Romero Fonseca, Ivan Dario

    The study of large plastic deformations has been the focus of numerous studies particularly in the metal forming processes and fracture mechanics fields. A good understanding of the plastic flow properties of metallic alloys and the true stresses and true strains induced during plastic deformation is crucial to optimize the aforementioned processes, and to predict ductile failure in fracture mechanics analyzes. Knowledge of stresses and strains is extracted from the true stress-strain curve of the material from the uniaxial tensile test. In addition, stress triaxiality is manifested by the neck developed during the last stage of a tensile test performed on a ductile material. This necking phenomenon is the factor responsible for deviating from uniaxial state into a triaxial one, then, providing an inaccurate description of the material's behavior after the onset of necking. The research of this dissertation is aimed at the development of a correction method for the nonuniform plastic deformation (post-necking) portion of the true stress-strain curve. The correction proposed is based on the well-known relationship between hardness and flow (yield) stress, except that instrumented nanoindentation hardness is utilized rather than conventional macro or micro hardness. Three metals with different combinations of strain hardening behavior and crystal structure were subjected to quasi-static tensile tests: power-law strain hardening low carbon G10180 steel (BCC) and electrolytic tough pitch copper C11000 (FCC), and linear strain hardening austenitic stainless steel S30400 (FCC). Nanoindentation hardness values, measured on the broken tensile specimen, were converted into flow stress values by means of the constraint factor C from Tabor's, the representative plastic strainepsilonr and the post-test true plastic strains measured. Micro Vickers hardness testing was carried out on the sample as well. The constraint factors were 5.5, 4.5 and 4.5 and the representative plastic

  5. Fabrication and characterization of baghdadite nanostructured scaffolds by space holder method.

    Science.gov (United States)

    Sadeghzade, Sorour; Shamoradi, Fateme; Emadi, Rahmatollah; Tavangarian, Fariborz

    2017-01-24

    Porous baghdadite scaffold has received great attention as a candidate for bone tissue engineering application due to its remarkable bioactivity, biocompatibility, and good bone formation ability. A few studies have been focused on improving the mechanical properties of baghdadite scaffolds. Recently, space holder method has been introduced as a new and viable technique to prepare bioceramic scaffolds with interconnected pores and suitable mechanical properties. In this study, for the first time, 3D baghdadite scaffolds with interconnected porosity were produced using space holder method. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were utilized to characterize various specimens. The baghdadite scaffolds were sintered at various temperatures in the range of 1250-1350°C for 3h. The compressive strength and compressive modulus measured to be in the range of 0.05-0.52MPa and 2.1-121.5MPa, respectively. The results showed that nanostructured baghdadite scaffolds with a crystallite size of about 32nm, 75% porosity and pores size in the range of 200-500µm can be successfully fabricated after sintering at 1350°C for 3h. Simulated body fluid (SBF) was used to evaluate the apatite formation ability of the scaffolds. The results showed the formation of an apatite layer on the scaffold surface which can be considered as a bioactivity criterion.

  6. TARGET DETECTION USING MULTI-RESOLUTION ANALYSIS AND HOLDER CONSTANT

    Institute of Scientific and Technical Information of China (English)

    Liu Wenyu; Li Hua; Zhu Guangxi

    2001-01-01

    Through analyzing the different height parameter of 3D surface between the artificial target and complex background based on the description of average Holder constant of fractional Brownian motion, a novel method of target detection based on wavelet transformation and Holder constant is proposed. The wavelet Holder constants are calculated and linearly interpolated in a series of images, the target is detected by testing the linearity errof The more accurate localization can be achieved using two images of the same region but with difIerent scaling parameters.The application results of this algorithm for target detection are also given, and show that this method has good performance of noise immunity. This method is also suitable for identifying specific targets in complex background.

  7. Broadband sample holder for microwave spectroscopy of superconducting qubits.

    Science.gov (United States)

    Averkin, A S; Karpov, A; Shulga, K; Glushkov, E; Abramov, N; Huebner, U; Il'ichev, E; Ustinov, A V

    2014-10-01

    We present a practical design and implementation of a broadband sample holder suitable for microwave experiments with superconducting integrated circuits at millikelvin temperatures. Proposed design can be easily integrated in standard dilution cryostats, has flat pass band response in a frequency range from 0 to 32 GHz, allowing the RF testing of the samples with substrate size up to 4 × 4 mm(2). The parasitic higher modes interference in the holder structure is analyzed and prevented via design considerations. The developed setup can be used for characterization of superconducting parametric amplifiers, bolometers, and qubits. We tested the designed sample holder by characterizing of a superconducting flux qubit at 20 mK temperature.

  8. Nonlinear Finite Element Analysis of Nanoindentation of Viral Capsids

    CERN Document Server

    Gibbons, M M; Gibbons, Melissa M.; Klug, William S.

    2006-01-01

    Recent Atomic Force Microscope (AFM) nanoindentation experiments measuring mechanical response of the protein shells of viruses have provided a quantitative description of their strength and elasticity. To better understand and interpret these measurements, and to elucidate the underlying mechanisms, this paper adopts a course-grained modeling approach within the framework of three-dimensional nonlinear continuum elasticity. Homogeneous, isotropic, elastic, thick shell models are proposed for two capsids: the spherical Cowpea Chlorotic Mottle Virus (CCMV), and the ellipsocylindrical bacteriophage $\\phi 29$. As analyzed by the finite element method, these models enable parametric characterization of the effects of AFM tip geometry, capsid dimensions, and capsid constitutive descriptions. The generally nonlinear force response of capsids to indentation is shown to be insensitive to constitutive details, and greatly influenced by geometry. Nonlinear stiffening and softening of the force response is dependent on ...

  9. Nanoindentation Studies of TNZ and Ti2448 Biomaterials After Magnetoelectropolishing

    Directory of Open Access Journals (Sweden)

    Hryniewicz T.

    2014-10-01

    Full Text Available This work presents the nanoindentation results of two newly developed titanium alloy biomaterials, TNZ and Ti2448, after different surface treatments. The investigations were performed on the samples, AR – as received, MP – after abrasive polishing, EP – after a standard electropolshing, and MEP – after magnetoelectropolishing. The electropolishing processes, both EP and MEP, were conducted in the same proprietary electrolyte based on concentrated sulfuric acid. The mechanical properties of the titanium alloys biomaterials demonstrated an evident dependence on the surface treatment method, with MEP samples revealing extremely different behaviour and mechanical properties. Such a different mechanical behaviour may mean completely different composition and thickness of the surface film formed on the studied samples after MEP

  10. Probing the cerium/cerium hydride interface using nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Brierley, Martin, E-mail: martin.brierley@awe.co.uk [Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR (United Kingdom); University of Manchester, Manchester M13 9PL (United Kingdom); Knowles, John, E-mail: john.knowles@awe.co.uk [Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR (United Kingdom)

    2015-10-05

    Highlights: • A disparity exists between the minimum energy and actual shape of a cerium hydride. • Cerium hydride is found to be harder than cerium metal by a ratio of 1.7:1. • A zone of material under compressive stress was identified surrounding the hydride. • No distribution of hardness was apparent within the hydride. - Abstract: A cerium hydride site was sectioned and the mechanical properties of the exposed phases (cerium metal, cerium hydride, oxidised cerium hydride) were measured using nanoindentation. An interfacial region under compressive stress was observed in the cerium metal surrounding a surface hydride that formed as a consequence of strain energy generated by the volume expansion associated with precipitation of the hydride phase.

  11. Adjustable Sample Holder With Pressure Contacts for Photoconductivity Measurement

    Directory of Open Access Journals (Sweden)

    Sanjeev Kumar

    2011-07-01

    Full Text Available A sample holder is designed to hold and apply pressure contacts on the electrodes of the photoconducting material to study the photoresponse transient. The sample holder is assembled on an aluminium base plate. The needle pointed probes are constrained to move under the spring action to provide the pressure contacts. One of the probes is provided with the facility of ± x directional movement to provide contacts on the samples having different spacing between the electrodes. The setup is simple in design and could find applications for the electrical measurements like dc conductivity and photoconductivity of semiconducting samples and can easily be assembled with scarp materials available in laboratories.

  12. MULTIPOINT BLANK HOLDER FORCE CONTROL IN HYDROFORMING OF FUEL TANK

    Institute of Scientific and Technical Information of China (English)

    WU Yousheng; WANG Xinyun; XIA Juchen; HU Guoan; SUN Yousong; YANG Lin

    2006-01-01

    The study of multipoint blank holder force(BHF) control is carried out for hydroforming a complicated shape motorcycle fuel tank. By finite element method (FEM) simulation, the configuration of multipoint blank holder cylinders and the setting of local BHF are optimized, and the influences of the multipoint BHF on the hydromechanical deep drawing and conventional hydroforming processes are studied. The desired fluid pressure and whole BHF are predicted for hydromechanical deep drawing process. Finally, simulation results are testified by forming experiment, and they are in agreement very well.

  13. Controlled Environment Specimen Transfer

    DEFF Research Database (Denmark)

    Damsgaard, Christian Danvad; Zandbergen, Henny W.; Hansen, Thomas Willum

    2014-01-01

    Specimen transfer under controlled environment conditions, such as temperature, pressure, and gas composition, is necessary to conduct successive complementary in situ characterization of materials sensitive to ambient conditions. The in situ transfer concept is introduced by linking an environme...

  14. Molten metal holder furnace and casting system incorporating the molten metal holder furnace

    Science.gov (United States)

    Kinosz, Michael J.; Meyer, Thomas N.

    2003-02-11

    A bottom heated holder furnace (12) for containing a supply of molten metal includes a storage vessel (30) having sidewalls (32) and a bottom wall (34) defining a molten metal receiving chamber (36). A furnace insulating layer (42) lines the molten metal receiving chamber (36). A thermally conductive heat exchanger block (54) is located at the bottom of the molten metal receiving chamber (36) for heating the supply of molten metal. The heat exchanger block (54) includes a bottom face (65), side faces (66), and a top face (67). The heat exchanger block (54) includes a plurality of electrical heaters (70) extending therein and projecting outward from at least one of the faces of the heat exchanger block (54), and further extending through the furnace insulating layer (42) and one of the sidewalls (32) of the storage vessel (30) for connection to a source of electrical power. A sealing layer (50) covers the bottom face (65) and side faces (66) of the heat exchanger block (54) such that the heat exchanger block (54) is substantially separated from contact with the furnace insulating layer (42).

  15. 12 CFR 563b.355 - What subscription rights must I give to each eligible account holder and each supplemental...

    Science.gov (United States)

    2010-01-01

    ... eligible account holder and each supplemental eligible account holder? 563b.355 Section 563b.355 Banks and... eligible account holder and each supplemental eligible account holder? (a) You must give each eligible account holder subscription rights to purchase conversion shares in an amount equal to the greater of:...

  16. On the phase transformation of single-crystal 4H-SiC during nanoindentation

    Science.gov (United States)

    Matsumoto, Mitsuhiro; Huang, Hu; Harada, Hirofumi; Kakimoto, Koichi; Yan, Jiwang

    2017-07-01

    Microstructural changes of single-crystal 4H silicon carbide (SiC) induced by nanoindentation under various conditions were investigated. It was found that nanoindentation at different crystal orientations induced different Raman spectroscopic characteristics. Cross-sectional observation by transmission electron microscopy indicated that a very deep subsurface damage region was formed where dislocations occurring along the basal planes, crystal grains rotation and micro-cracks were observed. The microstructures of the damage regions were strongly affected by the nanoindentation conditions. Coupled analysis of lattice fringes and Raman spectra indicated that a phase transformation from 4H-SiC to 3C-SiC occurred during nanoindentation, which has never been reported before. Furthermore, the 4H to 3C phase transformation strongly depended on the indenter orientation with respect to the SiC crystal. These findings are meaningful for low-damage precision machining of SiC substrates.

  17. Examination of Cast Iron Material Properties by Means of the Nanoindentation Method

    Directory of Open Access Journals (Sweden)

    Trytek A.

    2012-12-01

    Full Text Available The paper presents results of examination of material parameters of cast iron with structure obtained under rapid resolidification conditions carried out by means of the nanoindentation method.

  18. Examination of Cast Iron Material Properties by Means of the Nanoindentation Method

    Directory of Open Access Journals (Sweden)

    A. Trytek

    2012-12-01

    Full Text Available The paper presents results of examination of material parameters of cast iron with structure obtained under rapid resolidification conditions carried out by means of the nanoindentation method.

  19. Development of a novel nanoindentation technique by utilizing a dual-probe AFM system.

    Science.gov (United States)

    Cinar, Eyup; Sahin, Ferat; Yablon, Dalia

    2015-01-01

    A novel instrumentation approach to nanoindentation is described that exhibits improved resolution and depth sensing. The approach is based on a multi-probe scanning probe microscopy (SPM) tool that utilizes tuning-fork based probes for both indentation and depth sensing. Unlike nanoindentation experiments performed with conventional AFM systems using beam-bounce technology, this technique incorporates a second probe system with an ultra-high resolution for depth sensing. The additional second probe measures only the vertical movement of the straight indenter attached to a tuning-fork probe with a high spring constant and it can also be used for AFM scanning to obtain an accurate profiling. Nanoindentation results are demonstrated on silicon, fused silica, and Corning Eagle Glass. The results show that this new approach is viable in terms of accurately characterizing mechanical properties of materials through nanoindentation with high accuracy, and it opens doors to many other exciting applications in the field of nanomechanical characterization.

  20. Development of a novel nanoindentation technique by utilizing a dual-probe AFM system

    Directory of Open Access Journals (Sweden)

    Eyup Cinar

    2015-10-01

    Full Text Available A novel instrumentation approach to nanoindentation is described that exhibits improved resolution and depth sensing. The approach is based on a multi-probe scanning probe microscopy (SPM tool that utilizes tuning-fork based probes for both indentation and depth sensing. Unlike nanoindentation experiments performed with conventional AFM systems using beam-bounce technology, this technique incorporates a second probe system with an ultra-high resolution for depth sensing. The additional second probe measures only the vertical movement of the straight indenter attached to a tuning-fork probe with a high spring constant and it can also be used for AFM scanning to obtain an accurate profiling. Nanoindentation results are demonstrated on silicon, fused silica, and Corning Eagle Glass. The results show that this new approach is viable in terms of accurately characterizing mechanical properties of materials through nanoindentation with high accuracy, and it opens doors to many other exciting applications in the field of nanomechanical characterization.

  1. H\\"older continuity for Trudinger's equation in measure spaces

    CERN Document Server

    Kuusi, Tuomo; Siljander, Juhana; Urbano, José Miguel

    2011-01-01

    We complete the study of the regularity for Trudinger's equation by proving that weak solutions are H\\"older continuous also in the singular case. The setting is that of a measure space with a doubling non-trivial Borel measure supporting a Poincar\\'e inequality. The proof uses the Harnack inequality and intrinsic scaling.

  2. 38 CFR 36.4350 - Servicing procedures for holders.

    Science.gov (United States)

    2010-07-01

    ... providing needed information. (2) All borrowers must be informed of the system available for obtaining... the system at least annually. (c) Statement for income tax purposes. Before February 1st of each... administered by the Department of Housing and Urban Development. (e) Escrow accounts. A holder of a loan...

  3. 75 FR 34445 - Audit Program for Texas Flexible Permit Holders

    Science.gov (United States)

    2010-06-17

    ... regulatory stability for holders of Texas flexible permits. EPA is requesting informal comment on the Audit... implementation of the Audit Program at its discretion, as warranted. DATES: All comments should be submitted by...: Submit comments on the Audit Program, identified by Docket ID No. EPA-R06-OAR-2010-0510, by one of the...

  4. 24 CFR 401.556 - Leasing units to voucher holders.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Leasing units to voucher holders. 401.556 Section 401.556 Housing and Urban Development Regulations Relating to Housing and Urban... PROGRAM (MARK-TO-MARKET) Implementation of the Restructuring Plan After Closing § 401.556 Leasing units...

  5. 7 CFR 4279.78 - Repurchase from holder.

    Science.gov (United States)

    2010-01-01

    ... request by the Agency, the lender will furnish a current statement certified by an appropriate authorized... purposes to further its own financial gain. Any repurchase must only be made after the lender obtains the... from holder. (a) Repurchase by lender. A lender has the option to repurchase the unpaid...

  6. Test results of high-precision large cryogenic lens holders

    Science.gov (United States)

    Gal, C.; Reutlinger, A.; Boesz, A.; Leberle, T.; Mottaghibonab, A.; Eckert, P.; Dubowy, M.; Gebler, H.; Grupp, F.; Geis, N.; Bode, A.; Katterloher, R.; Bender, R.

    2012-09-01

    For the Euclid mission a Pre-Development phase is implemented to prove feasibility of individual components of the system [1]. The Near Infrared Spectrometer and Photometer (NISP) of EUCLID requires high precision large lens holders (?170 mm) at cryogenic temperatures (150K). The four lenses of the optical system are made of different materials: fused silica, CaF2, and LF5G15 that are mounted in a separate lens barrel design. Each lens has its separate mechanical interface to the lens barrel, the so called adaption ring. The performance of the lens holder design is verified by adapted test equipment and test facility including an optical metrology system. The characterization of the lens deformation and displacement (decenter, tilt) due to mechanical loads of the holder itself as well as thermally induced loads are driven by the required submicron precision range and the operational thermal condition. The surface deformation of the lens and its holder is verified by interferometric measurements, while tilt and position accuracy are measured by in-situ fibre based distance sensors. The selected distance measurement sensors have the capability to measure in a few mm range with submicron resolution in ultra high vacuum, in vibration environments and at liquid nitrogen temperatures and below. The calibration of the measurement system is of crucial importance: impacts such as temperature fluctuation, surface roughness, surface reflectivity, straylight effects, etc. on the measured distance are carefully calibrated. Inbuilt thermal expansion effects of the fibre sensors are characterized and proven with lens dummy with quasi zero CTE. The paper presents the test results and measured performance of the high precision large cryogenic lens holders attained by the metrology system. These results are presented on behalf of the EUCLID consortium.

  7. Dynamical approach to displacement jumps in nanoindentation experiments

    Science.gov (United States)

    K, Srikanth; Ananthakrishna, G.

    2017-01-01

    The load-controlled mode is routinely used in nanoindentation experiments. Yet there are no simulations or models that predict the generic features of force-displacement F -z curves, in particular, the existence of several displacement jumps of decreasing magnitude. Here, we show that the recently developed dislocation dynamical model predicts all the generic features when the model is appropriately coupled to an equation defining the load rate. Since jumps in the indentation depth result from the plastic deformation occurring inside the sample, we devise a method for calculating this contribution by setting up a system of coupled nonlinear time evolution equations for the mobile and forest dislocation densities. The equations are then coupled to the force rate equation. We include nucleation, multiplication, and propagation threshold mechanisms for the mobile dislocations apart from other well known dislocation transformation mechanisms between the mobile and forest dislocations. The commonly used Berkovitch indenter is considered. The ability of the approach is illustrated by adopting experimental parameters such as the indentation rate, the geometrical quantities defining the Berkovitch indenter including the nominal tip radius, and other parameters. We identify specific dislocation mechanisms contributing to different regions of the F -z curve as a first step for obtaining a good fit to a given experimental F -z curve. This is done by studying the influence of the parameters on the model F -z curves. In addition, the study demonstrates that the model predicts all the generic features of nanoindentation such as the existence of an initial elastic branch followed by several displacement jumps of decreasing magnitude, and residual plasticity after unloading for a range of model parameter values. Further, an optimized set of parameter values can be easily determined that gives a good fit to the experimental force-displacement curve for Al single crystals of (110

  8. Genomics and museum specimens.

    Science.gov (United States)

    Nachman, Michael W

    2013-12-01

    Nearly 25 years ago, Allan Wilson and colleagues isolated DNA sequences from museum specimens of kangaroo rats (Dipodomys panamintinus) and compared these sequences with those from freshly collected animals (Thomas et al. 1990). The museum specimens had been collected up to 78 years earlier, so the two samples provided a direct temporal comparison of patterns of genetic variation. This was not the first time DNA sequences had been isolated from preserved material, but it was the first time it had been carried out with a population sample. Population geneticists often try to make inferences about the influence of historical processes such as selection, drift, mutation and migration on patterns of genetic variation in the present. The work of Wilson and colleagues was important in part because it suggested a way in which population geneticists could actually study genetic change in natural populations through time, much the same way that experimentalists can do with artificial populations in the laboratory. Indeed, the work of Thomas et al. (1990) spawned dozens of studies in which museum specimens were used to compare historical and present-day genetic diversity (reviewed in Wandeler et al. 2007). All of these studies, however, were limited by the same fundamental problem: old DNA is degraded into short fragments. As a consequence, these studies mostly involved PCR amplification of short templates, usually short stretches of mitochondrial DNA or microsatellites. In this issue, Bi et al. (2013) report a breakthrough that should open the door to studies of genomic variation in museum specimens. They used target enrichment (exon capture) and next-generation (Illumina) sequencing to compare patterns of genetic variation in historic and present-day population samples of alpine chipmunks (Tamias alpinus) (Fig. 1). The historic samples came from specimens collected in 1915, so the temporal span of this comparison is nearly 100 years.

  9. 75 FR 62345 - Minimum Balance Requirement and Automatic Replenishment Option for Deposit Account Holders

    Science.gov (United States)

    2010-10-08

    ...-4] Minimum Balance Requirement and Automatic Replenishment Option for Deposit Account Holders AGENCY... account holders the option of automatic replenishment of their account via their bank account or credit... notify the account holder that replenishment of the account is needed, and places the pending...

  10. 10 CFR 1016.5 - Submission of procedures by access permit holder.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Submission of procedures by access permit holder. 1016.5 Section 1016.5 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) SAFEGUARDING OF RESTRICTED DATA General Provisions § 1016.5 Submission of procedures by access permit holder. No access permit holder shall...

  11. 13 CFR 120.651 - Claim to FTA by Registered Holder to replace Certificate.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Claim to FTA by Registered Holder... Holder to replace Certificate. (a) To replace a Certificate because of loss, theft, destruction, mutilation, or defacement, the Registered Holder must: (1) Give the FTA information about the Certificate...

  12. 27 CFR 13.76 - Service on applicant or certificate holder.

    Science.gov (United States)

    2010-04-01

    ... certificate holder. 13.76 Section 13.76 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND... applicant or certificate holder. (a) Method of service. TTB must serve notices of denial on an applicant by... revocation on a certificate holder by certified mail, return receipt requested, by a commercial...

  13. 14 CFR 119.43 - Certificate holder's duty to maintain operations specifications.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Certificate holder's duty to maintain... Chapter § 119.43 Certificate holder's duty to maintain operations specifications. (a) Each certificate holder shall maintain a complete and separate set of its operations specifications at its principal...

  14. 21 CFR 892.1880 - Wall-mounted radiographic cassette holder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Wall-mounted radiographic cassette holder. 892.1880 Section 892.1880 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... radiographic cassette holder. (a) Identification. A wall-mounted radiographic cassette holder is a device...

  15. 76 FR 61999 - Policy Statement: Inappropriate Design Approval Holder (DAH) Restrictions on the Use and...

    Science.gov (United States)

    2011-10-06

    ... Federal Aviation Administration 14 CFR Part 21 Policy Statement: Inappropriate Design Approval Holder (DAH... the proposed policy statement addressing the action taken by some Design Approval Holders (DAH...(b) requires the holder of a design approval to furnish at least one set of complete Instructions...

  16. 50 CFR 300.183 - Permit holder reporting and recordkeeping requirements.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Permit holder reporting and recordkeeping... Species § 300.183 Permit holder reporting and recordkeeping requirements. (a) Biweekly reports. Any person..., retained, or submitted pursuant to this subpart. A permit holder must allow NMFS or an authorized person...

  17. 32 CFR 767.9 - Content of permit holder's final report.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 5 2010-07-01 2010-07-01 false Content of permit holder's final report. 767.9... JURISDICATION OF THE DEPARTMENT OF THE NAVY Permit Guidelines § 767.9 Content of permit holder's final report. The permit holder's final report shall include the following: (a) A site history and a...

  18. 19 CFR 10.41b - Clearance of serially numbered substantial holders or outer containers.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Clearance of serially numbered substantial holders or outer containers. 10.41b Section 10.41b Customs Duties U.S. CUSTOMS AND BORDER PROTECTION... holders or outer containers. (a) The holders and containers described in this section may be...

  19. Reducing the nucleation barrier in magnetocaloric Heusler alloys by nanoindentation

    Directory of Open Access Journals (Sweden)

    R. Niemann

    2016-06-01

    Full Text Available Magnetocaloric materials are promising as solid state refrigerants for more efficient and environmentally friendly cooling devices. The highest effects have been observed in materials that exhibit a first-order phase transition. These transformations proceed by nucleation and growth which lead to a hysteresis. Such irreversible processes are undesired since they heat up the material and reduce the efficiency of any cooling application. In this article, we demonstrate an approach to decrease the hysteresis by locally changing the nucleation barrier. We created artificial nucleation sites and analyzed the nucleation and growth processes in their proximity. We use Ni-Mn-Ga, a shape memory alloy that exhibits a martensitic transformation. Epitaxial films serve as a model system, but their high surface-to-volume ratio also allows for a fast heat transfer which is beneficial for a magnetocaloric regenerator geometry. Nanoindentation is used to create a well-defined defect. We quantify the austenite phase fraction in its proximity as a function of temperature which allows us to determine the influence of the defect on the transformation.

  20. Reducing the nucleation barrier in magnetocaloric Heusler alloys by nanoindentation

    Science.gov (United States)

    Niemann, R.; Hahn, S.; Diestel, A.; Backen, A.; Schultz, L.; Nielsch, K.; Wagner, M. F.-X.; Fähler, S.

    2016-06-01

    Magnetocaloric materials are promising as solid state refrigerants for more efficient and environmentally friendly cooling devices. The highest effects have been observed in materials that exhibit a first-order phase transition. These transformations proceed by nucleation and growth which lead to a hysteresis. Such irreversible processes are undesired since they heat up the material and reduce the efficiency of any cooling application. In this article, we demonstrate an approach to decrease the hysteresis by locally changing the nucleation barrier. We created artificial nucleation sites and analyzed the nucleation and growth processes in their proximity. We use Ni-Mn-Ga, a shape memory alloy that exhibits a martensitic transformation. Epitaxial films serve as a model system, but their high surface-to-volume ratio also allows for a fast heat transfer which is beneficial for a magnetocaloric regenerator geometry. Nanoindentation is used to create a well-defined defect. We quantify the austenite phase fraction in its proximity as a function of temperature which allows us to determine the influence of the defect on the transformation.

  1. Mechanical properties of hyaline and repair cartilage studied by nanoindentation.

    Science.gov (United States)

    Franke, O; Durst, K; Maier, V; Göken, M; Birkholz, T; Schneider, H; Hennig, F; Gelse, K

    2007-11-01

    Articular cartilage is a highly organized tissue that is well adapted to the functional demands in joints but difficult to replicate via tissue engineering or regeneration. Its viscoelastic properties allow cartilage to adapt to both slow and rapid mechanical loading. Several cartilage repair strategies that aim to restore tissue and protect it from further degeneration have been introduced. The key to their success is the quality of the newly formed tissue. In this study, periosteal cells loaded on a scaffold were used to repair large partial-thickness cartilage defects in the knee joint of miniature pigs. The repair cartilage was analyzed 26 weeks after surgery and compared both morphologically and mechanically with healthy hyaline cartilage. Contact stiffness, reduced modulus and hardness as key mechanical properties were examined in vitro by nanoindentation in phosphate-buffered saline at room temperature. In addition, the influence of tissue fixation with paraformaldehyde on the biomechanical properties was investigated. Although the repair process resulted in the formation of a stable fibrocartilaginous tissue, its contact stiffness was lower than that of hyaline cartilage by a factor of 10. Fixation with paraformaldehyde significantly increased the stiffness of cartilaginous tissue by one order of magnitude, and therefore, should not be used when studying biomechanical properties of cartilage. Our study suggests a sensitive method for measuring the contact stiffness of articular cartilage and demonstrates the importance of mechanical analysis for proper evaluation of the success of cartilage repair strategies.

  2. Viscous-elastic-plastic behavior of bone using Berkovich nanoindentation

    Science.gov (United States)

    Olesiak, Sara E.; Oyen, Michelle L.; Ferguson, Virginia L.

    2010-05-01

    A series viscous-elastic-plastic (VEP) indentation model was expanded to include analysis of the common trapezoidal testing condition, consisting of constant loading—and unloading—rates with an intervening creep hold period. This full VEP model was applied to analyze nanoindentation test of three polymers and five different types of bone. The full VEP solution allows for direct determination of the viscous term as calculated from the creep hold, while the elastic and plastic material parameters were determined from a non-linear curve-fit of the unloading displacement-time data. Additionally, the use of the trapezoidal loading procedure permitted analysis of the unloading load-displacement data with traditional Oliver-Pharr analysis; the material properties from this analysis compared well with those obtained with VEP analysis. Using the full VEP solution and fitted material constants the loading and creep hold displacement-time curves were simulated and matched well to both polymer and bone experimental data. The full VEP solution shows great promise in for obtaining material parameters for many viscoelastic materials such as hydrated bone, polymers, and other biological tissues.

  3. Nanoindentation on the doubler plane of KDP single crystal

    Institute of Scientific and Technical Information of China (English)

    Guo Xiaoguang; Zhang Xiaoji; Tang Xianzhao; Guo Dongming; Gao Hang; Teng Xiaoji

    2013-01-01

    The nanohardness is from 1.44 to 2.61 GPa,the Vickers hardness is from 127 to 252 Vickers,and elastic modulus is from 52 to 123 GPa by the nanoindentation experiments on the doubler plane of KDP crystal.An indentation size effect is observed on the doubler plane in the test as the nanohardness and elastic modulus decreases with the increase of the maximum load.Slippage is identified as the major mode of plastic deformation,and pop-in events are attributed to the initiation of slippage.And the variation of unloading curve end is the result of stick effects between the indenter and the contact surface.The depth of the elastic deformation,which is between 40 and 75 nm,is responsible for the elastic deformation.The doubler plane of KDP crystal has anisotropy,and the relative anisotropy ofnanohardness is 8.2% and the relative anisotropy of elastic modulus is 8.0%.

  4. Nanoindentation and Adhesion Properties of Ta Thin Films

    Directory of Open Access Journals (Sweden)

    Yuan-Tsung Chen

    2013-01-01

    Full Text Available Ta films were sputtered onto a glass substrate with thicknesses from 500 Å to 1500 Å under the following conditions: (a as-deposited films were maintained at room temperature (RT, (b films were postannealed at TA=150°C for 1 h, and (c films were postannealed at TA=250°C for 1 h. X-ray diffraction (XRD results revealed that the Ta films had a body-centered cubic (BCC structure. Postannealing conditions and thicker Ta films exhibited a stronger Ta (110 crystallization than as-deposited and thinner films. The nanoindention results revealed that Ta thin films are sensitive to mean grain size, including a valuable hardness (H and Young’s modulus (E. High nanomechanical properties of as-deposited and thinner films can be investigated by grain refinement, which is consistent with the Hall-Petch effect. The surface energy of as-deposited Ta films was higher than that in postannealing treatments. The adhesion of as-deposited Ta films was stronger than postannealing treatments because of crystalline degree effect. The maximal H and E and the optimal adhesion of an as-deposited 500-Å-thick Ta film were 15.6 GPa, 180 GPa, and 51.56 mJ/mm2, respectively, suggesting that a 500-Å-thick Ta thin film can be used in seed and protective layer applications.

  5. Vision-Augmented Molecular Dynamics Simulation of Nanoindentation

    Directory of Open Access Journals (Sweden)

    Rajab Al-Sayegh

    2015-01-01

    Full Text Available We present a user-friendly vision-augmented technique to carry out atomic simulation using hand gestures. The system is novel in its concept as it enables the user to directly manipulate the atomic structures on the screen, in 3D space using hand gestures, allowing the exploration and visualisation of molecular interactions at different relative conformations. The hand gestures are used to pick and place atoms on the screen allowing thereby the ease of carrying out molecular dynamics simulation in a more efficient way. The end result is that users with limited expertise in developing molecular structures can now do so easily and intuitively by the use of body gestures to interact with the simulator to study the system in question. The proposed system was tested by simulating the crystal anisotropy of crystalline silicon during nanoindentation. A long-range (Screened bond order Tersoff potential energy function was used during the simulation which revealed the value of hardness and elastic modulus being similar to what has been found previously from the experiments. We anticipate that our proposed system will open up new horizons to the current methods on how an MD simulation is designed and executed.

  6. Mechanical characterization of cellulosic thecal plates in dinoflagellates by nanoindentation.

    Science.gov (United States)

    Lau, Ringo K L; Kwok, Alvin C M; Chan, W K; Zhang, T Y; Wong, Joseph T Y

    2007-02-01

    Dinoflagellates constitute an important group of microorganisms. Symbiotic dinoflagellates are responsible for the primary production of coral reef ecosystems and the phenomenon of their demise is known as "coral bleaching." Blooming of the planktonic dinoflagellates is the major cause of "red tides." Many dinoflagellates have prominent membrane-bound thecal plates at their cell cortices. These thecal plates have high cellulose content and are biologically fabricated into various shapes. However, the mechanical properties of theca have not previously been characterized; understanding these properties, including hardness and elastic modulus, will give insights into the ecological significance and biotechnological potential of bio-fabricated structures. A series of nanoindentation tests were performed on various locations of cellulosic thecal plates isolated from the dinoflagellates Alexandrium catenella and Lingulodinium polyedrum. Despite having transparent properties, thecal plates possess mechanical properties comparable to softwood cell walls, implicating their role as a protective cell covering. Consistent measurements were obtained when indentation was performed at various locations, which contrasts with the high variability of cellulose microfibers from plant sources. The present study demonstrated the novel properties of this potential new source of cellulose.

  7. Design of Injection Mold for the HOLDER-GEL Part in CD Writer%刻录机中HOLDER-GEL零件的注射模设计

    Institute of Scientific and Technical Information of China (English)

    许冬梅; 林充素; 王孙炫

    2009-01-01

    分析了刻录机中HOLDER-GEL零件的注射成型原理、注射工艺和其相关的工艺参数,论述了HOLDER-GEL零件的生产工艺,论证HOLDER-GEL零件的注射成型技术,阐述了该零件质量检验的意义和方法.

  8. Book Holder And Page Turner For The Elderly And Handicapped

    Science.gov (United States)

    Kerley, James; Eklund, Wayne

    1993-01-01

    Device holds reading matter and facilitates page turning for person not having use of arms and hands. Accommodates variety of publication formats, whether book, magazine, or newspaper. Holder sits on hospital-bed table and adjusted to convenient viewing angle. Includes flat upright back support for reading matter, hinged base, and main bracket with bent-wire page holders. Top support on back extended for such large items as newspapers. Wings on back support extended for oversize materials. Reader turns page by gripping special rod via mouthpiece, applying friction cup at its tip to page, and manipulating rod. Mouthpiece wide and tapered so user grips with teeth and uses jaws to move it, rather than using tongue or lips. Helpful to older people, whose facial and mouth muscles weak.

  9. Biaxial Creep Specimen Fabrication

    Energy Technology Data Exchange (ETDEWEB)

    JL Bump; RF Luther

    2006-02-09

    This report documents the results of the weld development and abbreviated weld qualification efforts performed by Pacific Northwest National Laboratory (PNNL) for refractory metal and superalloy biaxial creep specimens. Biaxial creep specimens were to be assembled, electron beam welded, laser-seal welded, and pressurized at PNNL for both in-pile (JOYO reactor, O-arai, Japan) and out-of-pile creep testing. The objective of this test campaign was to evaluate the creep behavior of primary cladding and structural alloys under consideration for the Prometheus space reactor. PNNL successfully developed electron beam weld parameters for six of these materials prior to the termination of the Naval Reactors program effort to deliver a space reactor for Project Prometheus. These materials were FS-85, ASTAR-811C, T-111, Alloy 617, Haynes 230, and Nirnonic PE16. Early termination of the NR space program precluded the development of laser welding parameters for post-pressurization seal weldments.

  10. Local H\\"older continuity for doubly nonlinear parabolic equations

    CERN Document Server

    Kuusi, Tuomo; Urbano, José Miguel

    2010-01-01

    We give a proof of the H\\"older continuity of weak solutions of certain degenerate doubly nonlinear parabolic equations in measure spaces. We only assume the measure to be a doubling non-trivial Borel measure which supports a Poincar\\'e inequality. The proof discriminates between large scales, for which a Harnack inequality is used, and small scales, that require intrinsic scaling methods.

  11. A Generalization of Holder's Inequality and Some Probability Inequalities

    OpenAIRE

    1992-01-01

    The main result of this article is a generalization of the generalized Holder inequality for functions or random variables defined on lower-dimensional subspaces of $n$-dimensional product spaces. It will be seen that various other inequalities are included in this approach. For example, it allows the calculation of upper bounds for the product measure of $n$-dimensional sets with the help of product measures of lower-dimensional marginal sets. Furthermore, it yields an interesting inequality...

  12. 关于Holder不等式%On Holder Inequality

    Institute of Scientific and Technical Information of China (English)

    何瑞强

    2012-01-01

    Famous Holder inequality plays an important role in the study of some disciplines such as mathematical analysis, harmonic analysis, functional analysis and partial differential equations. Not only its tips for using are flexibly, but also the results are very impressive. In this paper,a new method to prove Holder inequality on the basis of measurable functions was given. And generalized Holder inequality is given using mathematical induction forms. Last two important conclusions based on Holder inequality were got. These eonelusions lays the foundation for the equality's researches and applica- tions in the wider mathematics areas.%著名的Holder不等式在数学分析、调和分析、泛函分析以及偏微分方程等学科的研究中发挥着重要作用.该不等式不仅使用技巧灵活,而且得到的结果极其深刻.本文首先在可测函数论的基础上,给出Holder不等式的一种新的证明方法,然后利用数学归纳法导出Holder不等式的推广形式,最后应用Holder不等式得出两个重要结论,为该不等式在更广数学领域的研究和应用奠定了基础.

  13. Optimization of the blank holder force in cup drawing

    OpenAIRE

    Gharib, H.; A.S. Wifi,; M. Younan; Nassef, A

    2006-01-01

    Purpose: Develop an optimization strategy for the cup drawing process in order to produce a defect free deepdrawn cup.Design/methodology/approach: An optimization strategy for the blank holder force (BHF) scheme is proposedwhich searches for the BHF scheme that minimizes the maximum punch force and avoids process limits. Thisstrategy is applied to the linearly varying BHF scheme and compared to the constant BHF.Findings: The optimized linear BHF scheme resulted in an improved cup forming when...

  14. [Blood Count Specimen].

    Science.gov (United States)

    Tamura, Takako

    2015-12-01

    The circulating blood volume accounts for 8% of the body weight, of which 45% comprises cellular components (blood cells) and 55% liquid components. We can measure the number and morphological features of blood cells (leukocytes, red blood cells, platelets), or count the amount of hemoglobin in a complete blood count: (CBC). Blood counts are often used to detect inflammatory diseases such as infection, anemia, a bleeding tendency, and abnormal cell screening of blood disease. This count is widely used as a basic data item of health examination. In recent years, clinical tests before consultation have become common among outpatient clinics, and the influence of laboratory values on consultation has grown. CBC, which is intended to count the number of raw cells and to check morphological features, is easily influenced by the environment, techniques, etc., during specimen collection procedures and transportation. Therefore, special attention is necessary to read laboratory data. Providing correct test values that accurately reflect a patient's condition from the laboratory to clinical side is crucial. Inappropriate medical treatment caused by erroneous values resulting from altered specimens should be avoided. In order to provide correct test values, the daily management of devices is a matter of course, and comprehending data variables and positively providing information to the clinical side are important. In this chapter, concerning sampling collection, blood collection tubes, dealing with specimens, transportation, and storage, I will discuss their effects on CBC, along with management or handling methods.

  15. Compatibility of reduced activation ferritic/martensitic steel specimens with liquid Na and NaK in irradiation rig of IFMIF

    OpenAIRE

    2005-01-01

    In the high flux region of the International Fusion Materials Irradiation Facility (IFMIF), the neutron irradiation damage for iron-based alloys will exceed 20 dpa/ year. An accurate specimen temperature measurement under a large amount of nuclear heating is a key issue but the change of heat transfer of gap between irradiation specimens and specimen holder during irradiation test is inevitable, if gap is filled with an inert gas and temperature is monitored by a thermocouple buried in the sp...

  16. Molecular dynamics simulation of structural change at metal/semiconductor interface induced by nanoindenter

    Science.gov (United States)

    Zhao, Bing-Bing; Wang, Ying; Liu, Chang; Wang, Xiao-Chun

    2016-11-01

    The structures of the Si/Cu heterogenous interface impacted by a nanoindenter with different incident angles and depths are investigated in detail using molecular dynamics simulation. The simulation results suggest that for certain incident angles, the nanoindenter with increasing depth can firstly increase the stress of each atom at the interface and it then introduces more serious structural deformation of the Si/Cu heterogenous interface. A nanoindenter with increasing incident angle (absolute value) can increase the length of the Si or Cu extended atom layer. It is worth mentioning that when the incident angle of the nanoindenter is between -45° and 45°, these Si or Cu atoms near the nanoindenter reach a stable state, which has a lower stress and a shorter length of the Si or Cu extended atom layer than those of the other incident angles. This may give a direction to the planarizing process of very large scale integration circuits manufacture. Project supported by the Tribology Science Fund of State Key Laboratory of Tribology, China (Grant No. SKLTKF12A01), the National Natural Science Foundation of China (Grant No. 11474123), the Natural Science Foundation of Jilin Province of China (Grant No. 20130101011JC), and the Fundamental Research Funds for Central Universities at Jilin University, China.

  17. Structure-property-glass transition relationships in non-isocyanate polyurethanes investigated by dynamic nanoindentation

    Science.gov (United States)

    Weyand, Stephan; Blattmann, Hannes; Schimpf, Vitalij; Mülhaupt, Rolf; Schwaiger, Ruth

    2016-07-01

    Newly developed green-chemistry approaches towards the synthesis of non-isocyanate polyurethane (NIPU) systems represent a promising alternative to polyurethanes (PU) eliminating the need for harmful ingredients. A series of NIPU systems were studied using different nanoindentation techniques in order to understand the influence of molecular parameters on the mechanical behavior. Nanoindentation revealed a unique characteristic feature of those materials, i.e. stiffening with increasing deformation. It is argued that the origin of this observed stiffening is a consequence of the thermodynamic state of the polymer network, the molecular characteristics of the chemical building blocks and resulting anisotropic elastic response of the network structure. Flat-punch nanoindentation was applied in order to characterize the constitutive viscoelastic nature of the materials. The complex modulus shows distinct changes as a function of the NIPU network topology illustrating the influence of the chemical building blocks. The reproducibility of the data indicates that the materials are homogeneous over the volumes sampled by nanoindentation. Our study demonstrates that nanoindentation is very well-suited to investigate the molecular characteristics of NIPU materials that cannot be quantified in conventional experiments. Moreover, the technique provides insight into the functional significance of complex molecular architectures thereby supporting the development of NIPU materials with tailored properties.

  18. Hydrogen embrittlement, revisited by in situ electrochemical nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Barnoush, Afrooz

    2007-07-01

    The fine scale mechanical probing capability of NI-AFM was used to examine hydrogen interaction with plasticity. To realize this, an electrochemical three electrode setup was incorporated into the NI-AFM. The developed ECNI-AFM is capable of performing nanoindentation as well as imaging surfaces inside electrolytes. The developed ECNI-AFM setup was used to examine the effect of cathodically charged hydrogen on dislocation nucleation in pure metals and alloys. It was shown that hydrogen reduces the pop-in load in all of the tested materials except Cu. The reduced pop-in load can be interpreted as the HELP mechanism. Classical dislocation theory was used to model the homogeneous dislocation nucleation and it was shown that H reduces the activation energy for dislocation nucleation in H sensitive metals which are not undergoing a phase transformation. The activation energy for dislocation nucleation is related to the material specific parameters; shear modulus {mu}, dislocation core radius {rho} and in the case of partial dislocation nucleation, stacking fault energy {gamma}. These material properties can be influenced by H resulting in a reduced activation energy for dislocation nucleation. The universality of cohesion in bulk metals relates the reduction of the shear modulus to the reduction of the cohesion, meaning HEDE mechanism. The increase in the core radius of a dislocation due to H is a direct evidence of decrease in dislocation line energy and H segregation on the dislocation line. In the case of partial dislocations, the H can segregate on to the stacking fault ribbon and decrease {gamma}. This inhibits the cross slip process and enhances the slip planarity. Thus, HELP and HEDE are the two sides of a coin resulting in H embrittlement. However depending on the experimental approach utilized to probe the H effect, either HELP or HEDE can be observed. In this study, however, by utilizing a proper experimental approach, it was possible to resolve the

  19. NASA Biological Specimen Repository

    Science.gov (United States)

    McMonigal, K. A.; Pietrzyk, R. A.; Sams, C. F.; Johnson, M. A.

    2010-01-01

    The NASA Biological Specimen Repository (NBSR) was established in 2006 to collect, process, preserve and distribute spaceflight-related biological specimens from long duration ISS astronauts. This repository provides unique opportunities to study longitudinal changes in human physiology spanning may missions. The NBSR collects blood and urine samples from all participating ISS crewmembers who have provided informed consent. These biological samples are collected once before flight, during flight scheduled on flight days 15, 30, 60, 120 and within 2 weeks of landing. Postflight sessions are conducted 3 and 30 days after landing. The number of in-flight sessions is dependent on the duration of the mission. Specimens are maintained under optimal storage conditions in a manner that will maximize their integrity and viability for future research The repository operates under the authority of the NASA/JSC Committee for the Protection of Human Subjects to support scientific discovery that contributes to our fundamental knowledge in the area of human physiological changes and adaptation to a microgravity environment. The NBSR will institute guidelines for the solicitation, review and sample distribution process through establishment of the NBSR Advisory Board. The Advisory Board will be composed of representatives of all participating space agencies to evaluate each request from investigators for use of the samples. This process will be consistent with ethical principles, protection of crewmember confidentiality, prevailing laws and regulations, intellectual property policies, and consent form language. Operations supporting the NBSR are scheduled to continue until the end of U.S. presence on the ISS. Sample distribution is proposed to begin with selections on investigations beginning in 2017. The availability of the NBSR will contribute to the body of knowledge about the diverse factors of spaceflight on human physiology.

  20. Modelling of Specimen Fracture

    Science.gov (United States)

    2013-09-23

    the plate center. An end load of 1.0 MPa was applied. 1 2 3 Modelling of Specimen Fracture – Final Report 11 TR-13-47 Figure 2.5: Crack Geometry Figure...Christopher Bayley DRDC Atlantic Dockyard Laboratory Pacific CFB Esquimalt, Building 199 PO Box 17000, Station Forces Victoria, British Columbia Canada...q The weighting function, q , can be any arbitrary function within the J-integral domain, and must be zero on the domain boundary . An easy function

  1. Labeling of Patient Specimens

    Science.gov (United States)

    2011-01-26

    noted during the event that the actu.al number of near miss incidmts reported monthly was low due to laboratory personnel performing rounds each...specimens never leaves label and if moved it is labeled), All orders in system and all near misses and errors reported to patient safety Purchase/Install...Meeting 14 Aug 09, 1400 in lab break room thru out Develop TICK sheet to track near misses .JDI Ms. Clark Clinics will provide toPS 1st working day of

  2. Deformation behavior of Fe-based bulk metallic glass during nanoindentation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Fe-based bulk metallic glasses (BMGs) normally exhibit super high strength but significant brittleness at ambient temperature. Therefore,it is difficult to investigate the plastic deformation behavior and mechanism in these alloys through conven-tional tensile and compressive tests due to lack of distinct macroscopic plastic strain. In this work,the deformation behavior of Fe52Cr15Mo9Er3C15B6 BMG was in-vestigated through instrumented nanoindentation and uniaxial compressive tests. The results show that serrated flow,the typical plastic deformation feature of BMGs,could not be found in as-cast and partially crystallized samples during nanoinden-tation. In addition,the deformation behavior and mechanical properties of the alloy are insensitive to the applied loading rate. The mechanism for the appearance of the peculiar deformation behavior in the Fe-based BMG is discussed in terms of the temporal and spatial characteristics of shear banding during nanoindentation.

  3. Deformation behavior of Fe-based bulk metallic glass during nanoindentation

    Institute of Scientific and Technical Information of China (English)

    LI Lei; LIU Yuan; ZHANG TaiHua; GU JianSheng; WEI BingChen

    2008-01-01

    Fe-based bulk metallic glasses (BMGs) normally exhibit super high strength but significant brittleness at ambient temperature. Therefore, it is difficult to investigate the plastic deformation behavior and mechanism in these alloys through conven-tional tensile and compressive tests due to lack of distinct macroscopic plastic strain. In this work, the deformation behavior of Fe52Cr15Mo9Er3C15B6 BMG was in-vestigated through instrumented nanoindentation and uniaxial compressive tests. The results show that serrated flow, the typical plastic deformation feature of BMGs, could not be found in as-cast and partially crystallized samples during nanoinden-tation. In addition, the deformation behavior and mechanical properties of the alloy are insensitive to the applied loading rate. The mechanism for the appearance of the peculiar deformation behavior in the Fe-based BMG is discussed in terms of the temporal and spatial characteristics of shear banding during nanoindentation.

  4. 25 CFR 179.202 - May the holder of a life estate without regard to waste deplete the resources?

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false May the holder of a life estate without regard to waste... the holder of a life estate without regard to waste deplete the resources? Yes. The holder of a life... resources. However, a holder of a life estate without regard to waste may not cause or allow damage to...

  5. Influence of strain gradients on lattice rotation in nano-indentation experiments: A numerical study

    KAUST Repository

    Demiral, Murat

    2014-07-01

    In this paper the texture evolution in nano-indentation experiments was investigated numerically. To achieve this, a three-dimensional implicit finite-element model incorporating a strain-gradient crystal-plasticity theory was developed to represent accurately the deformation of a body-centred cubic metallic material. A hardening model was implemented to account for strain hardening of the involved slip systems. The surface topography around indents in different crystallographic orientations was compared to corresponding lattice rotations. The influence of strain gradients on the prediction of lattice rotations in nano-indentation was critically assessed. © 2014 Elsevier B.V..

  6. Molecular Dynamics Simulation of Nanoindentation-induced Mechanical Deformation and Phase Transformation in Monocrystalline Silicon

    Directory of Open Access Journals (Sweden)

    Jian Sheng-Rui

    2008-01-01

    Full Text Available AbstractThis work presents the molecular dynamics approach toward mechanical deformation and phase transformation mechanisms of monocrystalline Si(100 subjected to nanoindentation. We demonstrate phase distributions during loading and unloading stages of both spherical and Berkovich nanoindentations. By searching the presence of the fifth neighboring atom within a non-bonding length, Si-III and Si-XII have been successfully distinguished from Si-I. Crystallinity of this mixed-phase was further identified by radial distribution functions.

  7. Multiscale simulation and nanoindentation experimental study of initial plasticity of Fe single crystal

    Institute of Scientific and Technical Information of China (English)

    YUAN Lin; SHAN De-bin; GUO Bin

    2009-01-01

    It is very important to understand the initial plastic behavior of metals at microscale. In order to research the initial plasticity of body centered cubic metals in micro-/nano-scale, the multiscale simulation method and experimental study were used to study the nanoindentation process of Fe single crystal. The results show that the first abruption of load-displacement curve in nanoindentation of Fe single crystal can be attributed to the first transition from elastic to plastic deformation characterized by the dislocation emission.

  8. Type specimen studies in Pleurotus

    NARCIS (Netherlands)

    Petersen, Ronald H.; Krisai-Greilhuber, Irmgard

    1999-01-01

    An epitype specimen is designated for Pleurotus cornucopiae. Morphological examination of Mexican material and the type specimen of P. opuntiae showed that the distribution of this species includes North Africa and the highlands of Mexico. The type specimen of Lentinus (Pleurotus) eugrammus reveals

  9. 21 CFR 872.1905 - Dental x-ray film holder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental x-ray film holder. 872.1905 Section 872...) MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.1905 Dental x-ray film holder. (a) Identification. A dental x-ray film holder is a device intended to position and to hold x-ray film inside the...

  10. Nitrocellulose membrane sample holder using for terahertz time domain spectroscopy

    Science.gov (United States)

    Zhao, Xiaojing; Liu, Shangjian; Wang, Cuicui; Zuo, Jian; Zhang, Cunlin

    2016-11-01

    Terahertz (THz) technology has promising applications for the detection and identification of materials because it has a great advantage in measuring material fingerprint spectrum. Terahertz time-domain spectroscopy (THz-TDS) is a key technique that is applied to spectroscopic measurement of materials. However, it is difficult to press a pellet with small mass of sample and a bulking medium such as polyethylene (PE) powder usually need to be added. Characteristic absorption peaks of the solution in liquid cell is hard to be observed due to the interaction between materials and water molecules. Therefore, one method using the hydrophilic nitrocellulose (NC) membrane as a sample holder was applied to detect samples in an aqueous medium by THz-TDS. In this study, the α-lactose samples were mixed with 20 μl of deionized water and then applied directly onto the double-layered NC membrane sample holder. This mixture is located on the gap of two piece of NC membranes. Firstly the NC membranes with different pore sizes were tested in the experiment. And then the α-lactose solutions with different concentrations were measured on the NC with different pore sizes. Consequently, the small mass of samples can be detected and the characteristic absorption peaks become stronger with the increase of NC pore size. Moreover, compared to the traditional pellet-making and liquid cell detection, this membrane method is more convenient and easy to operate.

  11. INTERNATIONAL MOBILITY OF SPANISH MEN AND WOMEN DOCTORATE HOLDERS

    Directory of Open Access Journals (Sweden)

    Ana M. González Ramos

    2013-10-01

    Full Text Available Scientists are faced with many challenges along their international trajectory as they balance professional and family goals. Certain theoretical frameworks support the concept that career paths are shaped by social and institutional forces in science, whereas other theories point to family constraint factors as the reasoning behind scientists’ decisions to either go abroad or return home. Commonly, women scientists report many challenges when deciding to move internationally. In this paper we aim to exploit data from the Survey on Human Resources in Science and Technology, carried out by the Spanish Statistical Office in 2010, by analysing the life course of 4,123 Spanish doctorate holders. The results indicate there is a strong influence of institutional forces constituting a scientific culture which promotes rules and certain habits about how scientists should progress in their careers. Such forces lead to increasing rates of international mobility. At the same time, the data reveal that decisions about leaving and returning depend on the life course of the doctorate holder, and usually involve some family and personal considerations. Women have adopted a similar career track to men regarding international mobility, although women with children present low rates of high mobility and, by contrast, childless women present higher rates of high mobility than childless men.

  12. A cheap and quickly adaptable in situ electrical contacting TEM sample holder design.

    Science.gov (United States)

    Börrnert, Felix; Voigtländer, Ralf; Rellinghaus, Bernd; Büchner, Bernd; Rümmeli, Mark H; Lichte, Hannes

    2014-04-01

    In situ electrical characterization of nanostructures inside a transmission electron microscope provides crucial insight into the mechanisms of functioning micro- and nano-electronic devices. For such in situ investigations specialized sample holders are necessary. A simple and affordable but flexible design is important, especially, when sample geometries change, a holder should be adaptable with minimum effort. Atomic resolution imaging is standard nowadays, so a sample holder must ensure this capability. A sample holder design for on-chip samples is presented that fulfils these requisites. On-chip sample devices have the advantage that they can be manufactured via standard fabrication routes.

  13. Nanoscale piezoelectric response of ZnO nanowires measured using a nanoindentation technique.

    Science.gov (United States)

    Broitman, Esteban; Soomro, Muhammad Yousuf; Lu, Jun; Willander, Magnus; Hultman, Lars

    2013-07-14

    We report the piezoelectric properties of ZnO nanowires (NWs) obtained by using a nanoindenter with a conductive boron-doped diamond tip. The direct piezoelectric effect was measured by performing nanoindentations under load control, and the generated piezoelectric voltage was characterized as a function of the applied loads in the range 0.2-6 mN. The converse piezoelectric effect was measured by applying a DC voltage to the sample while there was a low applied force to allow the tip being always in physical contact with the NWs. Vertically aligned ZnO NWs were grown on inexpensive, flexible, and disposable paper substrates using a template-free low temperature aqueous chemical growth method. When using the nanoindenter to measure the direct piezoelectric effect, piezopotential values of up to 26 mV were generated. Corresponding measurement of the converse piezoelectric effect gave an effective piezoelectric coefficient d33(eff) of ∼9.2 pm V(-1). The ZnO NWs were also characterized using scanning electron microscopy, X-ray diffraction, and high-resolution transmission electron microscopy. The new nanoindentation approach provides a straightforward method to characterize piezoelectric material deposited on flexible and disposable substrates for the next generation of nanodevices.

  14. Multimillion atom simulation of materials on parallel computers — nanopixel, interfacial fracture, nanoindentation, and oxidation

    Science.gov (United States)

    Vashishta, Priya; Bachlechner, Martina; Nakano, Aiichiro; Campbell, Timothy J.; Kalia, Rajiv K.; Kodiyalam, Sanjay; Ogata, Shuji; Shimojo, Fuyuki; Walsh, Phillip

    2001-10-01

    We have developed scalable space-time multiresolution algorithms to enable molecular dynamics simulations involving up to a billion atoms on massively parallel computers. Large-scale molecular dynamics simulations have been used to study stress domains and interfacial fracture in semiconductor/dielectric nanopixels, nanoindentation, and oxidation of metallic nanoparticles.

  15. Combination of Instrumented Nanoindentation and Scanning Probe Microscopy for Adequate Mechanical Surface Testing

    Institute of Scientific and Technical Information of China (English)

    Enrico Tam; Mikhail Petrzhik; Dmitry Shtansky; Marie-Paule Delplancke-Ogletree

    2009-01-01

    The elastic indentation modulus and hardness of standard bulk materials and advanced thin films were deter-mined by using the nanoindentation technique followed by the Oliver- Pharr post-treatment. After measure-ments with different loading/unloading schemes on chemically polished bulk titanium a substantial decrease of both modulus and hardness vs an increasing loading time was found, Then, hard nanostructured TiBN and TiCrBN thin films deposited by magnetron sputtering (using multiphase targets) on substrates of high roughness (sintered hard metal) and low roughness (silicon) were studied. Experimental modulus and hardness characterized by using two different nanoindenter tools were within the limits of standard deviation. However, a strong effect of roughness on the spread of the experimental values was observed and it was found that hard-ness and elastic indentation modulus obeyed a Gaussian distribution. The experimental data were discussed together with scanning probe microscopy (SPM) images of typical imprints taken after the nanoindentation tests and the local topography's strong correlation with the results of nanoindentation was described.

  16. A nanoindentation study of magnetron co-sputtered nanocrystalline ternary nitride coatings

    Directory of Open Access Journals (Sweden)

    Yeung W.Y.

    2006-01-01

    Full Text Available Nanoindentation testing was used to determine the hardness, elastic modulus and plasticity parameter of three newly developed ternary nitride coatings with nano-sized grains. With decreasing nitrogen deposition pressure, grain diameter of the coatings decreases that leads to both higher nanohardness and elastic modulus with conservation of satisfactory values of plasticity characteristic.

  17. Cross sectional TEM observation and nanoindentation study of multilayered nanocomposite coatings

    NARCIS (Netherlands)

    Chen, C. Q.; Pei, Y. T.; Shaha, K. P.; De Hosson, J. Th. M.; Fan, JH; Chen, HB

    2008-01-01

    Combined nanoindentation and XTEM investigations were carried out on TiC/a-C nanocomposite coatings. The most striking findings related to the deformation and toughening mechanisms are: firstly, multiple shear bands delocalizing shear deformation and secondly nanoparticles flow and reordering in the

  18. Nanomechanical assessment of human and murine collagen fibrils via atomic force microscopy cantilever-based nanoindentation.

    Science.gov (United States)

    Andriotis, Orestis G; Manuyakorn, Wiparat; Zekonyte, Jurgita; Katsamenis, Orestis L; Fabri, Sebastien; Howarth, Peter H; Davies, Donna E; Thurner, Philipp J

    2014-11-01

    The nanomechanical assessment of collagen fibrils via atomic force microscopy (AFM) is of increasing interest within the biomedical research community. In contrast to conventional nanoindentation there exists no common standard for conducting experiments and analysis of data. Currently used analysis approaches vary between studies and validation of quantitative results is usually not performed, which makes comparison of data from different studies difficult. Also there are no recommendations with regards to the maximum indentation depth that should not be exceeded to avoid substrate effects. Here we present a methodology and analysis approach for AFM cantilever-based nanoindentation experiments that allows efficient use of captured data and relying on a reference sample for determination of tip shape. Further we show experimental evidence that maximum indentation depth on collagen fibrils should be lower than 10-15% of the height of the fibril to avoid substrate effects and we show comparisons between our and other approaches used in previous works. While our analysis approach yields similar values for indentation modulus compared to the Oliver-Pharr method we found that Hertzian analysis yielded significantly lower values. Applying our approach we successfully and efficiently indented collagen fibrils from human bronchi, which were about 30 nm in size, considerably smaller compared to collagen fibrils obtained from murine tail-tendon. In addition, derived mechanical parameters of collagen fibrils are in agreement with data previously published. To establish a quantitative validation we compared indentation results from conventional and AFM cantilever-based nanoindentation on polymeric samples with known mechanical properties. Importantly we can show that our approach yields similar results when compared to conventional nanoindentation on polymer samples. Introducing an approach that is reliable, efficient and taking into account the AFM tip shape, we anticipate

  19. Electrode holder useful in a corrosion testing device

    Science.gov (United States)

    Murphy, Jr., Robert J.; Jamison, Dale E.

    1986-01-01

    The present invention is directed to an apparatus and method for holding one or more test electrodes of precisely known exposed surface area. The present invention is particularly useful in a device for determining the corrosion properties of the materials from which the test electrodes have been formed. The present invention relates to a device and method for holding the described electrodes wherein the exposed surface area of the electrodes is only infinitesimally decreased. Further, in the present invention the exposed, electrically conductive surface area of the contact devices is small relative to the test electrode surface area. The holder of the present invention conveniently comprises a device for contacting and engaging each test electrode at two point contacts infinitesimally small in relation to the exposed surface area of the electrodes.

  20. Application of Thermal Tool Holder in Mechanical Engineering

    Science.gov (United States)

    Kunstfeld, Jaroslav; Hajnyš, Jiří; Brychta, Josef; Hemžský, Pavel; Nicielnik, Henryk

    2016-10-01

    The paper is focused on testing the thermal tool holder during milling operation from the point of view shimmy and roughness machined surface of the equipped tool. Experimental work will include testing of surface roughness parameters of the machined surface structural steel 1.0553 (Fe510C1) in combination with the monolith three-lips cutter Kennametal F3AU177BDK38 from cemented carbide coated with TiAIN PVD coating. Experimental machining will distinguish the climb milling and conventional milling and will be done under predetermined conditions, always at 15 cycles and in relation to other types of fixture devices. All testing will be done at a sufficiently rigid machine CNC FGS 40/50. During machining will be measured and subsequently evaluated power machine during the milling process, shimmy and selected parameters of the roughness of the machined surface.

  1. 19 CFR 134.23 - Containers or holders designed for or capable of reuse.

    Science.gov (United States)

    2010-04-01

    ... reuse. 134.23 Section 134.23 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND... Containers or holders designed for or capable of reuse. (a) Usual and ordinary reusable containers or holders... capable of reuse after the contents have been consumed, whether imported full or empty, must...

  2. Holder's and Hardy's Two Dimensional Diamond-alpha Inequalities on Time Scales

    CERN Document Server

    Ammi, Moulay Rchid Sidi

    2010-01-01

    We prove a two dimensional Holder and reverse-Holder inequality on time scales via the diamond-alpha integral. Other integral inequalities are established as well, which have as corollaries some recent proved Hardy-type inequalities on time scales.

  3. 30 CFR 250.1010 - General requirements for pipeline right-of-way holders.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false General requirements for pipeline right-of-way holders. 250.1010 Section 250.1010 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE... Rights-of-Way § 250.1010 General requirements for pipeline right-of-way holders. An applicant,...

  4. A sample holder for the study of isothermal heat of hydration of cement

    DEFF Research Database (Denmark)

    Hansen, Per Freiesleben; Jensen, Ole Mejlhede

    1998-01-01

    Different techniques for measuring heat of hydration of cement are discussed, and a sample holder designed specially for measuring isothermal heat of hydration is described. A particular characteristic of the sample holder is the vacuum mixing technique which ensures a momentary and homogeneous...

  5. 76 FR 42130 - Agency Information Collection Activities: BioWatch Filter Holder Log

    Science.gov (United States)

    2011-07-18

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY Agency Information Collection Activities: BioWatch Filter Holder Log AGENCY: Department of... agent. ] Analysis Agency: Department of Homeland Security. Title: BioWatch Filter Holder Log. OMB...

  6. 21 CFR 316.30 - Annual reports of holder of orphan-drug designation.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Annual reports of holder of orphan-drug designation. 316.30 Section 316.30 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... of holder of orphan-drug designation. Within 14 months after the date on which a drug was...

  7. 49 CFR Appendix C to Part 172 - Dimensional Specifications for Recommended Placard Holder

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Dimensional Specifications for Recommended Placard Holder C Appendix C to Part 172 Transportation Other Regulations Relating to Transportation PIPELINE AND... Specifications for Recommended Placard Holder EC02MR91.061...

  8. Quick-Change Ceramic Flame Holder for High-Output Torches

    Science.gov (United States)

    Haskin, Henry

    2010-01-01

    Researchers at NASA's Langley Research Center have developed a new ceramic design flame holder with a service temperature of 4,000 F (2,204 C). The combination of high strength and high temperature capability, as well as a twist-lock mounting method to the steel burner, sets this flame holder apart from existing technology.

  9. 37 CFR 7.38 - Notice to holder of extension of protection.

    Science.gov (United States)

    2010-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Notice to holder of extension of protection. 7.38 Section 7.38 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND... the Act for Extension of Protection to the United States § 7.38 Notice to holder of extension...

  10. 42 CFR 60.53 - Notification to lender or holder of change in enrollment status.

    Science.gov (United States)

    2010-10-01

    ... SERVICES GRANTS HEALTH EDUCATION ASSISTANCE LOAN PROGRAM The School § 60.53 Notification to lender or holder of change in enrollment status. Each school must notify the holder of a HEAL loan of any change in... failure to enroll as scheduled for any academic period as a full-time student, the student's latest...

  11. 77 FR 4398 - Safety Advisory Notice: Return of Radioactively Contaminated Tissue Holders Purchased From Bed...

    Science.gov (United States)

    2012-01-27

    ... Contaminated Tissue Holders Purchased From Bed Bath and Beyond AGENCY: Pipeline and Hazardous Materials Safety Administration (PHMSA), DOT. ACTION: Safety Advisory Notice. SUMMARY: PHMSA has been notified that Bed Bath and... of the contaminated tissue holders that they should arrange with Bed Bath and Beyond for their...

  12. Technologies to promote the inclusion of Indigenous knowledge holders in digital cultural heritage preservation

    DEFF Research Database (Denmark)

    Koch Kapuire, Gereon; Winschiers-Theophilus, Heike; Stanley, Colin

    2017-01-01

    Indigenous Knowledge (IK) preservation is at the core of our collaborative efforts with indigenous communities in Namibia. Recognising the local IK holder as a key agent in the process, we co-design technologies that enable IK holders in the rural communities to collect their own IK. An imperativ...

  13. Practical aspects of the use of the X{sup 2} holder for HRTEM-quality TEM sample preparation by FIB

    Energy Technology Data Exchange (ETDEWEB)

    Mierlo, Willem van, E-mail: VanmiW01@matthey.com [Materialwissenschaftliche Elektronenmikroskopie, University of Ulm (Germany); Geiger, Dorin [Materialwissenschaftliche Elektronenmikroskopie, University of Ulm (Germany); Robins, Alan; Stumpf, Matthias; Ray, Mary Louise; Fischione, Paul [E.A. Fischione Instruments, Inc., 9003 Corporate Circle, Export, PA 15632 (United States); Kaiser, Ute [Materialwissenschaftliche Elektronenmikroskopie, University of Ulm (Germany)

    2014-12-15

    The X{sup 2} holder enables the effective production of thin, electron transparent samples for high-resolution transmission electron microscopy (HRTEM). Improvements to the X{sup 2} holder for high-quality transmission electron microscopy (TEM) sample preparation are presented in this paper. We discuss the influence of backscattered electrons (BSE) from the sample holder in determining the lamella thickness in situ and demonstrate that a significant improvement in thickness determination can be achieved by comparatively simple means using the relative BSE intensity. We show (using Monte Carlo simulations) that by taking into account the finite collection angle of the electron backscatter detector, an approximately 20% underestimation of the lamella thickness in a silicon sample can be avoided. However, a correct thickness determination for light-element lamellas still remains a problem with the backscatter method; we introduce a more accurate method using the energy dispersive X-ray spectroscopy (EDX) signal for in situ thickness determination. Finally, we demonstrate how to produce a thin lamella with a nearly damage-free surface using the X{sup 2} holder in combination with sub-kV polishing in the Fischione Instruments' NanoMill{sup ®} TEM specimen preparation system. - Highlights: • Improvements to the thickness determination for FIB-prepared lamellae are presented. • A new method for thickness determination using the EDX-signal is presented. • Large area HRTEM-quality lamella can be prepared using these methods. • A lamella with minimal surface damage can be prepared using the X2-method and NanoMill®.

  14. 78 FR 48456 - Notice of Cancellation of Customs Broker Licenses Due to Death of the License Holder

    Science.gov (United States)

    2013-08-08

    ... of the License Holder AGENCY: U.S. Customs and Border Protection, Department of Homeland Security... death of the license holders. SUPPLEMENTARY INFORMATION: Notice is hereby given that, pursuant...

  15. A novel method for single sample multi-axial nanoindentation of hydrated heterogeneous tissues based on testing great white shark jaws.

    Science.gov (United States)

    Ferrara, Toni L; Boughton, Philip; Slavich, Eve; Wroe, Stephen

    2013-01-01

    Nanomechanical testing methods that are suitable for a range of hydrated tissues are crucial for understanding biological systems. Nanoindentation of tissues can provide valuable insights into biology, tissue engineering and biomimetic design. However, testing hydrated biological samples still remains a significant challenge. Shark jaw cartilage is an ideal substrate for developing a method to test hydrated tissues because it is a unique heterogeneous composite of both mineralized (hard) and non-mineralized (soft) layers and possesses a jaw geometry that is challenging to test mechanically. The aim of this study is to develop a novel method for obtaining multidirectional nanomechanical properties for both layers of jaw cartilage from a single sample, taken from the great white shark (Carcharodon carcharias). A method for obtaining multidirectional data from a single sample is necessary for examining tissue mechanics in this shark because it is a protected species and hence samples may be difficult to obtain. Results show that this method maintains hydration of samples that would otherwise rapidly dehydrate. Our study is the first analysis of nanomechanical properties of great white shark jaw cartilage. Variation in nanomechanical properties were detected in different orthogonal directions for both layers of jaw cartilage in this species. The data further suggest that the mineralized layer of shark jaw cartilage is less stiff than previously posited. Our method allows multidirectional nanomechanical properties to be obtained from a single, small, hydrated heterogeneous sample. Our technique is therefore suitable for use when specimens are rare, valuable or limited in quantity, such as samples obtained from endangered species or pathological tissues. We also outline a method for tip-to-optic calibration that facilitates nanoindentation of soft biological tissues. Our technique may help address the critical need for a nanomechanical testing method that is applicable

  16. A novel method for single sample multi-axial nanoindentation of hydrated heterogeneous tissues based on testing great white shark jaws.

    Directory of Open Access Journals (Sweden)

    Toni L Ferrara

    Full Text Available Nanomechanical testing methods that are suitable for a range of hydrated tissues are crucial for understanding biological systems. Nanoindentation of tissues can provide valuable insights into biology, tissue engineering and biomimetic design. However, testing hydrated biological samples still remains a significant challenge. Shark jaw cartilage is an ideal substrate for developing a method to test hydrated tissues because it is a unique heterogeneous composite of both mineralized (hard and non-mineralized (soft layers and possesses a jaw geometry that is challenging to test mechanically. The aim of this study is to develop a novel method for obtaining multidirectional nanomechanical properties for both layers of jaw cartilage from a single sample, taken from the great white shark (Carcharodon carcharias. A method for obtaining multidirectional data from a single sample is necessary for examining tissue mechanics in this shark because it is a protected species and hence samples may be difficult to obtain. Results show that this method maintains hydration of samples that would otherwise rapidly dehydrate. Our study is the first analysis of nanomechanical properties of great white shark jaw cartilage. Variation in nanomechanical properties were detected in different orthogonal directions for both layers of jaw cartilage in this species. The data further suggest that the mineralized layer of shark jaw cartilage is less stiff than previously posited. Our method allows multidirectional nanomechanical properties to be obtained from a single, small, hydrated heterogeneous sample. Our technique is therefore suitable for use when specimens are rare, valuable or limited in quantity, such as samples obtained from endangered species or pathological tissues. We also outline a method for tip-to-optic calibration that facilitates nanoindentation of soft biological tissues. Our technique may help address the critical need for a nanomechanical testing method

  17. Effect of native oxide mechanical deformation on InP nanoindentation

    Science.gov (United States)

    Almeida, C. M.; Prioli, R.; Ponce, F. A.

    2008-12-01

    Native oxide has been found to have a noticeable effect on the mechanical deformation of InP during nanoindentation. The indentations were performed using spherical diamond tips and the residual impressions were studied by atomic force microscopy. It has been observed that in the early stages of mechanical deformation, plastic flow occurs in the oxide layer while the indium phosphide is still in the elastic regime. The deformed native oxide layer results in a pile-up formation that causes an increase in the contact area between the tip and the surface during the nanoindentation process. This increase in the projected contact area is shown to contribute to the apparent high pressure sustained by the crystal before the onset of plastic deformation. It is also shown that the stress necessary to generate the first dislocations from the crystal surface is ˜3 GPa higher than the stress needed for slip to occur when dislocations are already present in the crystalline structure.

  18. Nanoindentation of TiO{sub 2} thin films with different microstructures

    Energy Technology Data Exchange (ETDEWEB)

    Gaillard, Yves; Jimenez-Pique, Emilio [Dept. Ciencia de Materiales e Ingenieria Metalurgica, Universistat Politecnica de Catalunya, Avda. Diagonal 647 (ETSEIB), 08028 Barcelona (Spain); Rico, Victor J; Gonzalez-Elipe, AgustIn R [Instituto de Ciencia de Materiales de Sevilla (CSIC-Univ. Sevilla). Avda. Americo Vespucio 49. 41092 Sevilla (Spain)

    2009-07-21

    A series of nanoindentation tests has been carried out with TiO{sub 2} films produced by physical vapour deposition (PVD) under different conditions. Films with different microstructures and crystallographic structures have been prepared by changing experimental parameters such as the temperature of the substrate, the deposition angle (by the so-called glancing angle physical vapour deposition, GAPVD) or by exposing the growing film to a beam of accelerated ions. The obtained results of hardness and Young's modulus depict interesting correlations with the microstructure and structure of the films providing a general picture for the relationships between these characteristics and their mechanical properties. Different models have been used to extract Young's modulus and hardness parameters from the experimental nanoindentation curves. The obtained results are critically discussed to ascertain the ranges of validity of each procedure according to the type of sample investigated.

  19. Light-Curing Volumetric Shrinkage in Dimethacrylate-Based Dental Composites by Nanoindentation and PAL Study

    Science.gov (United States)

    Shpotyuk, Olha; Adamiak, Stanislaw; Bezvushko, Elvira; Cebulski, Jozef; Iskiv, Maryana; Shpotyuk, Oleh; Balitska, Valentina

    2017-01-01

    Light-curing volumetric shrinkage in dimethacrylate-based dental resin composites Dipol® is examined through comprehensive kinetics research employing nanoindentation measurements and nanoscale atomic-deficient study with lifetime spectroscopy of annihilating positrons. Photopolymerization kinetics determined through nanoindentation testing is shown to be described via single-exponential relaxation function with character time constants reaching respectively 15.0 and 18.7 s for nanohardness and elastic modulus. Atomic-deficient characteristics of composites are extracted from positron lifetime spectra parameterized employing unconstrained x3-term fitting. The tested photopolymerization kinetics can be adequately reflected in time-dependent changes observed in average positron lifetime (with 17.9 s time constant) and fractional free volume of positronium traps (with 18.6 s time constant). This correlation proves that fragmentation of free-volume positronium-trapping sites accompanied by partial positronium-to-positron traps conversion determines the light-curing volumetric shrinkage in the studied composites.

  20. Nanoindentation study of interphases in epoxy/amine thermosetting systems modified with thermoplastics.

    Science.gov (United States)

    Ramos, Jose Angel; Blanco, Miren; Zalakain, Iñaki; Mondragon, Iñaki

    2009-08-15

    The characterization of a mixture of epoxy/amine with different stoichiometric ratios was carried out by means of nanoindentation. The epoxy system was composed by diglycidyl ether of bisphenol-A and 4,4'-methylene bis-(3-chloro 2,6-diethylaniline). Diffusion through interface formed by epoxy/amine system in stoichiometric ratio and several thermoplastic polymers was also analyzed by means of stiffness analysis, as studied by atomic force microscopy (AFM) and coupled nanoindentation tests. Used thermoplastics were an amorphous, atactic polystyrene, and two semicrystalline, syndiotactic polystyrene and poly(phenylene sulfide). Larger range diffusion was obtained in epoxy/amine systems modified with atactic polystyrene while the study of the influence of stoichiometric ratio suggests that the excess of epoxy generated stiffer material. In addition, larger indentation loads resulted in higher apparent stiffness because of the more number of polymer chains that had to re-accommodate owing to the increase in contact area.

  1. Deformation behavior during nanoindentation in Ce-based bulk metallic glasses

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lingchen; XING Dongmei; ZHANG Taihua; WEI Bingchen; LI Weihuo; WANG Yuren

    2006-01-01

    The deformation behavior and the effect of the loading rate on the plastic deformation in Ce-based bulk metallic glasses (BMGs) were investigated through nanoindentation tests. The results showed that the loading rate dependence of plastic deformation during nanoindentation measurements in the Ce-based BMGs is quite unique in contrast to that of other BMG alloys. The load-displacement (P-h)curves of Ce60Al15Cu10Ni15 BMG exhibit a homogeneous plastic deformation at low loading rates, and a prominent serrated flow at high strain rates, whereas,the P-h curves of Ce65Al10Cu10Ni10Nb5 exhibit homogenous plastic deformation at all studied loading rates. The room temperature creep behavior could clearly be observed in these two alloys. The mechanism of the unique plastic deformation feature in the Ce-based BMGs was studied.

  2. MEMS sensor for in situ TEM-nanoindentation with simultaneous force and current measurements

    Science.gov (United States)

    Nafari, A.; Angenete, J.; Svensson, K.; Sanz-Velasco, A.; Enoksson, P.

    2010-06-01

    A capacitive force sensor for in situ transmission electron microscope (TEM)-nanoindentation with simultaneous force and current measurement has been developed. The sensor was fabricated using bulk micro machining methods such as deep reactive ion etch, thermal oxidation, metal deposition and anodic bonding. Two different geometries of the sensor were designed to allow in situ TEM electromechanical experiments in the most common TEM instruments. Electrical probing is enabled by an on-chip insulator, electrically separating the indenter tip and the capacitor used for force measurements. The sensor was designed for the force range of 0 to 4.5 mN. Finally, we demonstrate for the first time in situ TEM-nanoindentation with simultaneous force and current measurements.

  3. Hardness and yield strength of dentin from simulated nano-indentation tests.

    Science.gov (United States)

    Toparli, M; Koksal, N S

    2005-03-01

    The finite element method (FEM) is applied for studying the hardness (H) and yield strength (Y) of dentin subjected to a nano-indentation process. The nano-indentation experiments were simulated with the ABAQUS finite element software package. This test, performed with a spherical indenter, was simulated by axisymmetric finite element analysis. The load versus displacement was calculated during loading-unloading sequence for different elastic modulus (E) and yield strength. Hardness and maximum principal compressive and tensile stresses were plotted for different elastic modulus depending on yield strength. The dentin was assumed to be isotropic, homogenous and elasto-plastic. The theoretical results outlined in this study were compared with the experimental works reported in the literature and then hardness and yield strength of dentin was estimated.

  4. Nanoindentation characterisation of human colorectal cancer cells considering cell geometry, surface roughness and hyperelastic constitutive behaviour

    Science.gov (United States)

    Boccaccio, Antonio; Uva, Antonio E.; Papi, Massimiliano; Fiorentino, Michele; De Spirito, Marco; Monno, Giuseppe

    2017-01-01

    Characterisation of the mechanical behaviour of cancer cells is an issue of crucial importance as specific cell mechanical properties have been measured and utilized as possible biomarkers of cancer progression. Atomic force microscopy certainly occupies a prominent place in the field of the mechanical characterisation devices. We developed a hybrid approach to characterise different cell lines (SW620 and SW480) of the human colon carcinoma submitted to nanoindentation measurements. An ad hoc algorithm was written that compares the force-indentation curves experimentally retrieved with those predicted by a finite element model that simulates the nanoindentation process and reproduces the cell geometry and the surface roughness. The algorithm perturbs iteratively the values of the cell mechanical properties implemented in the finite element model until the difference between the experimental and numerical force-indentation curves reaches the minimum value. The occurrence of this indicates that the implemented material properties are very close to the real ones. Different hyperelastic constitutive models, such as Arruda-Boyce, Mooney-Rivlin and Neo-Hookean were utilized to describe the structural behaviour of indented cells. The algorithm was capable of separating, for all the cell lines investigated, the mechanical properties of cell cortex and cytoskeleton. Material properties determined via the algorithm were different with respect to those obtained with the Hertzian contact theory. This demonstrates that factors such as: the cell geometry/anatomy and the hyperelastic constitutive behaviour, which are not contemplated in the Hertz’s theory hypotheses, do affect the nanoindentation measurements. The proposed approach represents a powerful tool that, only on the basis of nanoindentation measurements, is capable of characterising material at the subcellular level.

  5. MD simulation of the effect of contact area and tip radius on nanoindentation

    Institute of Scientific and Technical Information of China (English)

    CHEN; Shangda; KE; Fujiu

    2004-01-01

    Molecular dynamics simulations of nanoindentation are performed on monocrystal copper. A new "contact atoms" method is presented for calculating the contact area. Compared with conventional methods, this method can provide the contact area more accurately not only for sink-in but also for pile-up situation. The effect of tip radius on indentation is investigated too. The results indicate that the measured hardness of the material will become higher as the tip radius increases.

  6. Nanomechanical characterization of nanostructured bainitic steel: Peak Force Microscopy and Nanoindentation with AFM

    OpenAIRE

    2015-01-01

    The full understanding of the deformation mechanisms in nanostructured bainite requires the local characterization of its mechanical properties, which are expected to change from one phase, bainitic ferrite, to another, austenite. This study becomes a challenging process due to the bainitic nanostructured nature and high Young’s modulus. In this work, we have carried out such study by means of the combination of AFM-based techniques, such as nanoindentation and Peak Force Quantitative Nanomec...

  7. Combined nanoindentation testing and scanning electron microscopy of bone and articular calcified cartilage in an equine fracture predilection site

    Directory of Open Access Journals (Sweden)

    M Doube

    2010-06-01

    Full Text Available Condylar fracture of the third metacarpal bone (Mc3 is the commonest cause of racetrack fatality in Thoroughbred horses. Linear defects involving hyaline articular cartilage, articular calcified cartilage (ACC and subchondral bone (SCB have been associated with the fracture initiation site, which lies in the sagittal grooves of the Mc3 condyle. We discovered areas of thickened and abnormally-mineralised ACC in the sagittal grooves of several normal 18-month-old horses, at the same site that linear defects and condylar fracture occur in older Thoroughbreds and questioned whether this tissue had altered mechanical properties. We embedded bone slices in PMMA, prepared flat surfaces normal to the articular surface and studied ACC and SCB using combined quantitative backscattered electron scanning electron microscopy (qBSE and nanoindentation testing: this allowed correlation of mineralisation density and tissue stiffness (E at the micron scale. We studied both normal and affected grooves, and also normal condylar regions. Large arrays of indentations could be visualised as 2-dimensional maps of E with a limit to resolution of indentation spacing, which is much larger than qBSE pixel spacing. ACC was more highly mineralised but less stiff in early linear defects than in control regions, while subchondral bone was more highly mineralised and stiffer in specimens with early linear defects than those without. Thus both ACC and SCB mineralisation may be abnormal in a class of early linear defect in 18-month-old Thoroughbred horses, and this may possibly contribute to later fracture of the Mc3 condyle.

  8. 13 CFR 120.522 - Payment of accrued interest to the Lender or Registered Holder when SBA purchases the guaranteed...

    Science.gov (United States)

    2010-01-01

    ... Lender or Registered Holder when SBA purchases the guaranteed portion. 120.522 Section 120.522 Business... accrued interest to the Lender or Registered Holder when SBA purchases the guaranteed portion. (a) Rate of interest. If SBA purchases the guaranteed portion from a Lender or from a Registered Holder (if sold in...

  9. 26 CFR 1.1272-3 - Election by a holder to treat all interest on a debt instrument as OID.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 11 2010-04-01 2010-04-01 true Election by a holder to treat all interest on a... Gains and Losses § 1.1272-3 Election by a holder to treat all interest on a debt instrument as OID. (a) Election. A holder of a debt instrument may elect to include in gross income all interest that accrues...

  10. 25 CFR 179.101 - How does the Secretary distribute principal and income to the holder of a life estate?

    Science.gov (United States)

    2010-04-01

    ... the holder of a life estate? 179.101 Section 179.101 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF... § 179.101 How does the Secretary distribute principal and income to the holder of a life estate? (a... specify a distribution of proceeds; (2) Where the vested holders of remainder interests and the...

  11. 50 CFR 600.1416 - Requirements for exempted state designation based on submission of state license holder data.

    Science.gov (United States)

    2010-10-01

    ... designation based on submission of state license holder data. 600.1416 Section 600.1416 Wildlife and Fisheries... Requirements for exempted state designation based on submission of state license holder data. (a) A state must... dates of birth for its license holders/registrants. The waters of the state for which such...

  12. Nanoindentation studies of ex situ AlN/Al metal matrix nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Fale, Sandeep; Likhite, Ajay; Bhatt, Jatin, E-mail: jatinbhatt@mme.vnit.ac.in

    2014-12-05

    Highlights: • Formation of in-situ phases nucleated on AlN particles strengthens the matrix. • Formation of in-situ phases increases with AlN content in nanocomposites. • Stronger in-situ phases results in increased hardness and modulus of elasticity. - Abstract: Nanocrystalline Aluminium nitride (AlN) powder is dispersed in different weight ratio in Aluminum matrix to fabricate metal matrix nanocomposite (MMNC) using ex situ melt metallurgy process. The synthesized Al–AlN nanocomposites are studied for phase analysis using high resolution scanning electron microscopy (FEG-SEM) and for hardness behavior using microindentation and nanoindentation tests. Quantitative analysis of the oxide phases is calculated from thermodynamic data and mass balance equation using elemental data obtained from energy dispersive spectroscopy (EDS) results. Role of oxide phases in association with AlN particles is investigated to understand the mechanical behavior of composites using nanoindentation tester. Load–displacement profile obtained from nanoindentation test reveals distribution of oxide phases along with AlN particle and their effect on indent penetration.

  13. Dynamic characteristics of nanoindentation in Ni:A molecular dynamics simulation study

    Institute of Scientific and Technical Information of China (English)

    Muhammad Imran; Fayyaz Hussain; Muhammad Rashid; S.A.Ahmad

    2012-01-01

    In this work,three-dimensional molecular dynamics simulation is carried out to elucidate the nanoindentation behaviour of single crystal Ni.The substrate indenter system is modelled using hybrid interatomic potentials including the manybody potential (embedded atom method) and two-body Morse potential.The spherical indenter is chosen,and the simulation is performed for different loading rates from 10 m/s to 200 m/s.Results show that the maximum indentation load and hardness of the system increase with the increase of velocity.The effect of indenter size on the nanoindentation response is also analysed.It is found that the maximum indentation load is higher for the large indenter whereas the hardness is higher for the smaller indenter.Dynamic nanoindentation is carried out to investigate the behaviour of Ni substrate to multiple loading-unloading cycles.It is observed from the results that the increase in the number of loading unloading cycles reduces the maximum load and hardness of the Ni substrate.This is attributed to the decrease in recovery force due to defects and dislocations produced after each indentation cycle.

  14. Conventional Nanoindentation in Self-Assembled Monolayers Deposited on Gold and Silver Substrates

    Directory of Open Access Journals (Sweden)

    Leila Costelle

    2012-01-01

    Full Text Available Self-assembled monolayers (SAMs are promising materials for micromechanical applications. However, characterization of mechanical properties of monolayers is challenging for standard nanoindentation, and new efficient analysis techniques are needed. Hereby, a conventional nanoindentation method has been combined in a unique way with efficient data analysis based on consumed energy calculation and load-displacement data. The procedure has been applied on SAMs of 4,4′-biphenyldithiol (BPDT on Au, 1-tetradecanethiol (TDT, and 1-hexadecanethiol (HDT on Au and Ag substrates being the first study where SAMs of the same thiols on different substrates are analyzed by nanoindentation providing a new insight into the substrate effects. Unlike TDT and HDT SAMs, which are found to strongly enhance the homogeneity and stiffness of the underlying substrate, the BPDT covered Au substrate appears softer in mechanical response. In the case of TDT and HDT SAMs on Ag the structures are softer showing also faster relaxation than the corresponding structures on Au substrate. The proposed procedure enables a fast and efficient way of assessing the complex behaviour of SAM modified substrates. As a consequence, the results are relevant to practical issues dependent on layer activity and toughness.

  15. Measuring residual stress in ceramic zirconia-porcelain dental crowns by nanoindentation.

    Science.gov (United States)

    Zhang, Y; Allahkarami, M; Hanan, J C

    2012-02-01

    Residual stress plays a critical role in failure of ceramic dental crowns. The magnitude and distribution of residual stress in the crown system are largely unknown. Determining the residual stress quantitatively is challenging since the crown has such complex contours and shapes. This work explored the feasibility and validity of measuring residual stress of zirconia and porcelain in ceramic crowns by nanoindentation. Nanoindentation tests were performed on the cross-section of a crown for both porcelain and zirconia along four critical locations: the thickest, thinnest and medium porcelain thicknesses. Zirconia and porcelain pieces, chipped off from the crown and annealed at 400 °C, were used as reference samples. The residual stress was determined by comparing the measured hardness of the stressed sample with that of the reference sample. Nanoindentation impression images were acquired through a scanning probe microscope (SPM) equipped with a Hysitron Triboindenter. Zirconia showed large pile-up. Residual stress is determined along the thickness of crowns at the chosen locations for both porcelain and zirconia. The measured results were compared with the results from X-ray diffraction (XRD) and finite element modeling (FEM). Results show there are large amounts of residual stresses in the dental crown and their magnitude differs between locations due to the complex shape of the crown. The average residual stress readings were as high as -637 MPa and 323 MPa for zirconia and porcelain respectively.

  16. Nanomechanical behaviors of (110) and (111) CdZnTe crystals investigated by nanoindentation

    Institute of Scientific and Technical Information of China (English)

    LI Yan; KANG Renke; GAO Hang; WANG Jinghe; LANG Yanju

    2009-01-01

    The nanomechanical behaviors of (110) and (111) CdZnTe crystals were investigated by nanoindentation. It was found that the indenter tip was adhered by the removed materials in scanning testing area although the scanning force on the tested surface was very small (1000 nN), which would affect the testing result of nanoindentation, so the indenter was clean before nanoindentation test. The experimemtal results showed that the hardness and Young's modulus decreased with the increase of indentation loads on the same plane. Because of the anisot-ropy of the CdZnTe crystal, the average hardness of (110) plane is 35% lower than that of (l 11 ) plane, and there are about 30% difference of the hardness along different crystallographic directions on the same plane. The hardness in 0° and 120° testing directions was the same due to the threefold symmetry of a Berkovich indenter. And the anisotropy affected the surface quality during machining of CdZnTe crystal.

  17. Pancreatic duct holder for facilitating duct-to-mucosa pancreatojejunostomy after pancreatoduodenectomy.

    Science.gov (United States)

    Sugiyama, Masanori; Suzuki, Yutaka; Abe, Nobutsugu; Ueki, Hisayo; Masaki, Tadahiko; Mori, Toshiyuki; Atomi, Yutaka

    2009-01-01

    Duct-to-mucosa pancreatojejunostomy after pancreatoduodenectomy may be technically difficult, particularly in cases in which the remnant pancreas is soft with a small main pancreatic duct. We devised a pancreatic duct holder for duct-to-mucosa pancreatojejunostomy. The holder has a cone-shaped tip. A one-third circle of the tip is cut away, which makes a slit. As the tip is inserted gently into the pancreatic duct, the duct can be adequately expanded. The holder provides a good surgical field for anastomosis. A slit of the tip allows needle insertion. The holder facilitates stitches of the jejunum also. Twelve patients underwent pancreatoduodenectomy, followed by duct-to-mucosa pancreatojejunostomy using the holder. The holder allowed 8 or more stitches in duct-to-mucosa anastomosis, even in patients with a small pancreatic duct. No patients developed prolonged pancreatic leakage or pancreatic fistula postoperatively. In conclusion, the pancreatic duct holder is a simple and useful tool for facilitating duct-to-mucosa pancreatojejunostomy.

  18. 2003 Dead Bald Eagle Specimen

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The specimen report states the Bald Eagle was found along the side of the I-95 by a motorist who contacted Santee National Wildlife Refuge. The Bald Eagle was taken...

  19. A new holder and surface MRI coil for the examination of the newborn infant hip.

    Science.gov (United States)

    Krasny, R; Casser, H R; Requardt, H; Botschek, A

    1993-01-01

    A special holder was developed for examination of the infant hip joint using MRI. This holder allows the infant hip joint to be examined both in a neutral position and in various defined functional positions. A special integrated surface coil, also developed for this purpose, provides the high spatial resolution required for assessment of the fine joint structures. Thirty infants were examined and the new device has proved useful in advanced hip dysplasia, therapy-resistant subluxation and luxation, and for operative therapy planning (reconstruction of the acetabular roof, redirectional osteotomies). Interpretation errors due to misprojection can be eliminated to a large extent since the holder allows standardized and reproducible positioning.

  20. Manufacturing of Plutonium Tensile Specimens

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, Cameron M [Los Alamos National Laboratory

    2012-08-01

    Details workflow conducted to manufacture high density alpha Plutonium tensile specimens to support Los Alamos National Laboratory's science campaigns. Introduces topics including the metallurgical challenge of Plutonium and the use of high performance super-computing to drive design. Addresses the utilization of Abaqus finite element analysis, programmable computer numerical controlled (CNC) machining, as well as glove box ergonomics and safety in order to design a process that will yield high quality Plutonium tensile specimens.

  1. Fatigue damage observed non-destructively in fibre composite coupon test specimens by X-ray CT

    DEFF Research Database (Denmark)

    Jespersen, Kristine Munk; Mikkelsen, Lars Pilgaard

    2016-01-01

    This study presents a method for monitoring the 3D fatigue damage progression on a micro-structural level in a glass fibre/polymer coupon test specimen by means of laboratory X-ray Computed Tomography (CT). A modified mount and holder made for the standard test samples to fit into the X-ray CT...... scanner along with a tension clamp solution is presented. Initially, the same location of the test specimen is inspected by ex-situ X-ray CT during the fatigue loading history, which shows the damage progression on a micro-structural level. The openings of individual uni-directional (UD) fibre fractures...

  2. Experimental verification of a deep drawing tool system for adaptive blank holder pressure distribution

    DEFF Research Database (Denmark)

    Tommerup, Søren; Endelt, Benny Ørtoft

    2012-01-01

    In deep drawing, the strain path in the blank during the forming process can be significantly affected by application of temporal and spatial variation of the blank holder force. In this study, an active tool system capable of controlling the distribution of the blank holder force is presented...... which can be integrated into existing stacked deep drawing tools without need for modification of the press. A working system is presented consisting of a controller, designated volume displacement cavity pressure supply units and a shimming plate. It is applied to the deep drawing of a rectangular...... geometry using a conventional stacked tool design. The shimming plate is used to support the blank holder plate, and has four integrated hydraulic cavities in which the pressure can be controlled individually whereby a controlled deflection of the blank holder plate is achieved analogous...

  3. The prospect of biogas among small-holder dairy goat farmers in the ...

    African Journals Online (AJOL)

    The prospect of biogas among small-holder dairy goat farmers in the Uluguru ... African Journal of Food, Agriculture, Nutrition and Development ... In Mgeta ward, Morogoro region, introduction of Norwegian dairy goats in the 1980s has ...

  4. Fabrication of Metallic Biomedical Scaffolds with the Space Holder Method: A Review

    National Research Council Canada - National Science Library

    Arifvianto, Budi; Zhou, Jie

    2014-01-01

    ... possessed by this type of materials to those of polymeric and ceramic materials. The space holder method has been recognized as one of the viable methods for the fabrication of metallic biomedical scaffolds...

  5. Direct observation of unstained biological specimens in water by the frequency transmission electric-field method using SEM.

    Directory of Open Access Journals (Sweden)

    Toshihiko Ogura

    Full Text Available Scanning electron microscopy (SEM is a powerful tool for the direct visualization of biological specimens at nanometre-scale resolution. However, images of unstained specimens in water using an atmospheric holder exhibit very poor contrast and heavy radiation damage. Here, we present a new form of microscopy, the frequency transmission electric-field (FTE method using SEM, that offers low radiation damage and high-contrast observation of unstained biological samples in water. The wet biological specimens are enclosed in two silicon nitride (SiN films. The metal-coated SiN film is irradiated using a focused modulation electron beam (EB at a low-accelerating voltage. A measurement terminal under the sample holder detects the electric-field frequency signal, which contains structural information relating to the biological specimens. Our results in very little radiation damage to the sample, and the observation image is similar to the transmission image, depending on the sample volume. Our developed method can easily be utilized for the observation of various biological specimens in water.

  6. Endoscopic Septoplasty-Two Handed Technique with Endoscope Holder: A Novel Approach.

    Science.gov (United States)

    Khan, Mubarak M; Parab, Sapna R

    2016-12-01

    The popularity of endoscopes has been expanding not only in diagnostics but also in therapeutics. The traditional septal surgery also has come under the purview of endoscopic surgery in the last few decades. Endoscopic septoplasty has definitely many advantages over the conventional procedure. But the only disadvantage of endoscopic surgery is that it is a single handed technique as the other hand is used for holding the endoscope which may compromise the overall surgical time as the hemostasis and suctioning of the surgical field off the blood cannot be done simultaneously, in addition to the surgeon fatigue associated with holding the endoscope in the left hand. Endoscope holder allows both hands of the surgeon to be free for surgical manipulation and also imitates more or less same actions of the left hand. To report the preliminary use of Khan's endoscope holder for endoscopic septoplasty. Prospective Non Randomized Clinical Study. Khan's Endoscope Holder, which was primarily designed for endoscopic ear surgery, has been used for two handed technique of endoscopic septoplasty. The design of the Endoscope holder is described in detail. A total of 49 endoholder assisted endoscopic septoplasties were operated from Nov 2014 to Jan 2015 in MIMER Medical College and Sushrut ENT Hospital, Talegaon D, Pune, India. Our Endoscope Holder is a good option for two handed technique in Endoscopic Septoplasty due to its advantages. The study reports the successful usage and applicability of the endo holder for endoscopic Septoplasty. Level of evidence IV.

  7. Influence of Curing Units and Indirect Restorative Materials on the Hardness of Two Dual-curing Resin Cements Evaluated by the Nanoindentation Test.

    Science.gov (United States)

    Kuguimiya, Rosiane Noqueira; Rode, Kátia Martins; Carneiro, Paula Mendes Acatauassú; Aranha, Ana Cecilia Corrêa; Turbino, Miriam Lacalle

    2015-06-01

    To evaluate the hardness of a dual-curing self-adhesive resin cement (RelyX U200) and a conventional dual-curing resin cement (RelyX ARC) cured with different light curing units of different wavelengths (Elipar Freelight 2 LED [430 to 480 nm, conventional], Bluephase LED [380 to 515 nm, polywave], AccuCure 3000 Laser [488 nm]) by means of the nanoindentation test. Bovine incisors were cleaned and then sectioned at the cementoenamel junction to remove the crown. After embedding in acrylic, dentin surfaces of the specimens were exposed and ground flat to standardize the surfaces. To simulate clinically placing indirect restorations, ceramic (IPS e.maxPress/Ivoclar Vivadent) or indirect composite resin (SR Adoro/Ivoclar Vivadent) slabs were cemented on dentin surfaces. The specimens were sectioned longitudinally at low speed under constant irrigation and then polished. In the positive control group, the cement was light cured without the interposition of indirect restorative material; in the negative control group, after the indirect restorative material was cemented, no light curing was performed, allowing only chemical polymerization of the cement. All specimens were stored in distilled water at 37°C for 7 days. Nanoindentadion hardness of the cement layer was measured under a 100-mN load. Data were statistically analyzed using ANOVA and Tukey's test (p < 0.05). Although the self-adhesive cement is technically simple, conventional cement showed the best polymerization performance. The polywave LED technology did not differ significantly from other light-curing units. The hardness of the resin cements evaluated was negatively influenced by the interposition of an indirect restorative material; only the LEDs were able to maintain the same degree of cement polymerization when an indirect restorative material was used. The photoactivation step is required during the cementation of indirect restorations to ensure adequate polymerization of dual-curing resin cements.

  8. Atomic-level simulations of nanoindentation-induced phase transformation in mono-crystalline silicon

    Science.gov (United States)

    Lin, Yen-Hung; Chen, Tei-Chen; Yang, Ping-Feng; Jian, Sheng-Rui; Lai, Yi-Shao

    2007-12-01

    Molecular dynamics (MD) simulations of nanoindentation are carried out to investigate the phase transformations in Si with a spherical indenter. Since the phase transformation induced by deformation in micro-scale is closely related to the carrier mobility of the material, it has become a key issue to be investigated for the chips especially with smaller feature size. Up to now, however, it is not possible to carry out the nanoindentation experimentally in such a small feature. Consequently, molecular dynamic simulation on nanoindentation is resorted to and becomes a powerful tool to understand the detailed mechanisms of stress-induced phase transformation in nano-scale. In this study, the inter-atomic interaction of Si atoms is modeled by Tersoff's potential, while the interaction between Si atoms and diamond indenter atoms is modeled by Morse potential. It is found that the diamond cubic structure of Si in the indentation zone transforms into a phase with body-centred tetragonal structure (β-Si) just underneath the indenter during loading stage and then changes to amorphous after unloading. By using the technique of coordinate number the results reveal that indentation on the (0 0 1) surface exhibits significant phase transformation along the direction. In addition, indentation on the (1 1 0) surface shows more significant internal slipping and spreading of phase transformation than on the (0 0 1) surface. Furthermore, during the indentation process phase transformations of Si are somewhat reversible. Parts of transformed phases that are distributed over the region of elastic deformation can be gradually recovered to original mono-crystal structure after unloading.

  9. Evaluation of elastic modulus and hardness of highly inhomogeneous materials by nanoindentation

    Science.gov (United States)

    Epshtein, Svetlana A.; Borodich, Feodor M.; Bull, Steve J.

    2015-04-01

    The experimental and numerical techniques for evaluation of mechanical properties of highly inhomogeneous materials are discussed. The techniques are applied to coal as an example of such a material. Characterization of coals is a very difficult task because they are composed of a number of distinct organic entities called macerals and some amount of inorganic substances along with internal pores and cracks. It is argued that to avoid the influence of the pores and cracks, the samples of the materials have to be prepared as very thin and very smooth sections, and the depth-sensing nanoindentation (DSNI) techniques has to be employed rather than the conventional microindentation. It is shown that the use of the modern nanoindentation techniques integrated with transmitted light microscopy is very effective for evaluation of elastic modulus and hardness of coal macerals. However, because the thin sections are glued to the substrate and the glue thickness is approximately equal to the thickness of the section, the conventional DSNI techniques show the effective properties of the section/substrate system rather than the properties of the material. As the first approximation, it is proposed to describe the sample/substrate system using the classic exponential weight function for the dependence of the equivalent elastic contact modulus on the depth of indentation. This simple approach allows us to extract the contact modulus of the material constitutes from the data measured on a region occupied by a specific component of the material. The proposed approach is demonstrated on application to the experimental data obtained by Berkovich nanoindentation with varying maximum depth of indentation.

  10. Reliable measurement of elastic modulus of cells by nanoindentation in an atomic force microscope

    KAUST Repository

    Zhou, Zhoulong

    2012-04-01

    The elastic modulus of an oral cancer cell line UM1 is investigated by nanoindentation in an atomic force microscope with a flat-ended tip. The commonly used Hertzian method gives apparent elastic modulus which increases with the loading rate, indicating strong effects of viscoelasticity. On the contrary, a rate-jump method developed for viscoelastic materials gives elastic modulus values which are independent of the rate-jump magnitude. The results show that the rate-jump method can be used as a standard protocol for measuring elastic stiffness of living cells, since the measured values are intrinsic properties of the cells. © 2011 Elsevier Ltd.

  11. A rate-jump method for characterization of soft tissues using nanoindentation techniques

    KAUST Repository

    Tang, Bin

    2012-01-01

    The biomechanical properties of soft tissues play an important role in their normal physiological and physical function, and may possibly relate to certain diseases. The advent of nanomechanical testing techniques, such as atomic force microscopy (AFM), nano-indentation and optical tweezers, enables the nano/micro-mechanical properties of soft tissues to be investigated, but in spite of the fact that biological tissues are highly viscoelastic, traditional elastic contact theory has been routinely used to analyze experimental data. In this article, a novel rate-jump protocol for treating viscoelasticity in nanomechanical data analysis is described. © 2012 The Royal Society of Chemistry.

  12. Thermomagnetic processing of liquid-crystalline epoxy resins and their mechanical characterization using nanoindentation.

    Science.gov (United States)

    Li, Yuzhan; Rios, Orlando; Kessler, Michael R

    2014-11-12

    A thermomagnetic processing method was used to produce a biphenyl-based liquid-crystalline epoxy resin (LCER) with oriented liquid-crystalline (LC) domains. The orientation of the LCER was confirmed and quantified using two-dimensional X-ray diffraction. The effect of molecular alignment on the mechanical and thermomechanical properties of the LCER was investigated using nanoindentation and thermomechanical analysis, respectively. The effect of the orientation on the fracture behavior was also examined. The results showed that macroscopic orientation of the LC domains was achieved, resulting in an epoxy network with an anisotropic modulus, hardness, creep behavior, and thermal expansion.

  13. Computer simulations of nanoindentation in Mg-Cu and Cu-Zr metallic glasses

    DEFF Research Database (Denmark)

    Paduraru, Anca; Andersen, Ulrik Grønbjerg; Thyssen, Anders

    2010-01-01

    The formation of shear bands during plastic deformation of Cu0.50Zr0.50 and Mg0.85Cu0.15 metallic glasses is studied using atomic-scale computer simulations. The atomic interactions are described using realistic many-body potentials within the effective medium theory, and are compared with similar...... simulations using a Lennard-Jones description of the material. The metallic glasses are deformed both in simple shear and in a simulated nanoindentation experiment. Plastic shear localizes into shear bands with a width of approximately 5 nm in CuZr and 8 nm in MgCu. In simple shear, the shear band formation...

  14. Nano-scratch study of molecular deposition (MD) films on silicon wafer using nanoindentation~1

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Experiment of the molecular deposition (MD) films with and without alkyl terminal de-posited on the silicon wafer were conducted by using nanoindentation. It was found that MD filmsand alkyl terminated MD films exhibit higher critical load (scratch resistance or adhesive strength)and lower coefficient of friction compared with the silicon substrate. Critical load (scratch resis-tance) increases with the number of layers, and coefficients of friction of those MD film with alkylterminal are still best for the same layer of MD film.

  15. Mechanical behavior of iron aluminides: A comparison of nanoindentation, compression and bending of micropillars

    Energy Technology Data Exchange (ETDEWEB)

    Zamanzade, Mohammad, E-mail: m.zamanzade@matsci.uni-sb.de [Saarland University, Institute of Material Science and Methods, Saarbrücken (Germany); Velayarce, Jorge Rafael [Saarland University, Institute of Material Science and Methods, Saarbrücken (Germany); Abad, Oscar Torrents [INM-Leibniz Institute for New Materials and Saarland University, Saarbrücken (Germany); Motz, Christian [Saarland University, Institute of Material Science and Methods, Saarbrücken (Germany); Barnoush, Afrooz [Norwegian University of Science and Technology (NTNU), Trondheim (Norway)

    2016-01-15

    Various local testing methods, namely, nanoindentation, compression and bending tests of micropillars were used to better understand the influence of ternary Cr atoms on the extrinsic and intrinsic mechanical properties of Fe{sub 3}Al intermetallics with the D0{sub 3} super lattice. Using such local techniques enables us to quantify the influence of Cr on the enhancement of the Young´s modulus. Furthermore, the effect of Cr on the yield stress, strain hardening and appearance of slip traces was studied based on the stress–strain curves and secondary electron micrographs of the bended and compressed pillars.

  16. High temperature nanoindentation hardness and Young's modulus measurement in a neutron-irradiated fuel cladding material

    Science.gov (United States)

    Kese, K.; Olsson, P. A. T.; Alvarez Holston, A.-M.; Broitman, E.

    2017-04-01

    Nanoindentation, in combination with scanning probe microscopy, has been used to measure the hardness and Young's modulus in the hydride and matrix of a high burn-up neutron-irradiated Zircaloy-2 cladding material in the temperature range 25-300 °C. The matrix hardness was found to decrease only slightly with increasing temperature while the hydride hardness was essentially constant within the temperature range. Young's modulus decreased with increasing temperature for both the hydride and the matrix of the high burn-up fuel cladding material. The hydride Young's modulus and hardness were higher than those of the matrix in the temperature range.

  17. Rate dependency of depth in nanoindentation of polycrystalline NiTi

    Directory of Open Access Journals (Sweden)

    Sun Q.P.

    2010-06-01

    Full Text Available The recent increased use of shape memory alloys (SMAs for engineering applications manifests the need of checking the aspect of rate in NiTi. The ability of models and experiments to accurately predict the rate dependency of function–rate relationship is important. This paper concentrates on the rate dependency of depth in nanoindentation of NiTi where different tips have been used. To explain the phenomena, hysteresis damping areas are investigated. The results show decreasing depth at higher rates is due to the amount of latent heat generated from phase transition and relaxation time for heat release.

  18. Comparison of mechanical properties of surface layers with use of nanoindentation and microindentation tests

    Directory of Open Access Journals (Sweden)

    M. Zeleňák

    2012-07-01

    Full Text Available The objective of the paper is a mutual comparison of different methods for evaluation of mechanical properties of surface layers. Mechanical properties were tested with the use of nanoindentation and microindentation tests. Different loads and constant deformation speed were used in both cases. For the evaluation of mechanical properties, the AISI 304 type Chromium-Nickel steel commonly used in mechanical engineering industry was tested. Knowledge of relations and differences between nano and micromechanical properties is necessary for understanding of mechanical processes continuously occurring in surface layers during cutting processes.

  19. Studying microstructure in molecular crystals with nanoindentation: intergrowth polymorphism in felodipine.

    Science.gov (United States)

    Mishra, Manish Kumar; Desiraju, Gautam R; Ramamurty, Upadrasta; Bond, Andrew D

    2014-11-24

    Intergrowth polymorphism refers to the existence of distinct structural domains within a single crystal of a compound. The phenomenon is exhibited by form II of the active pharmaceutical ingredient felodipine, and the associated microstructure is a significant feature of the compound's structural identity. Employing the technique of nanoindentation on form II reveals a bimodal mechanical response on specific single-crystal faces, demonstrating distinct properties for two polymorphic forms within the same crystal. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Atomic force microscopy based nanoindentation study of onion abaxial epidermis walls in aqueous environment

    Energy Technology Data Exchange (ETDEWEB)

    Xi, Xiaoning; Tittmann, Bernhard [Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Kim, Seong H. [Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2015-01-14

    An atomic force microscopy based nanoindentation method was employed to study how the structure of cellulose microfibril packing and matrix polymers affect elastic modulus of fully hydrated primary plant cell walls. The isolated, single-layered abaxial epidermis cell wall of an onion bulb was used as a test system since the cellulose microfibril packing in this cell wall is known to vary systematically from inside to outside scales and the most abundant matrix polymer, pectin, can easily be altered through simple chemical treatments such as ethylenediaminetetraacetic acid and calcium ions. Experimental results showed that the pectin network variation has significant impacts on the cell wall modulus, and not the cellulose microfibril packing.

  1. Elastic Properties of Human Mandibule Measured by Nanoindentation%纳米压痕法用于人下颌骨弹性模量的测量

    Institute of Scientific and Technical Information of China (English)

    辛鹏飞; 聂璞林; 王旭东; 沈国芳; 杨丹苓

    2011-01-01

    目的:对既往文献中所采用的纳米压痕技术进行横向比较并推荐出制作时间短、对实验结果影响较小的实验项目.方法:获取一具人新鲜尸体下颌骨,应用推荐的实验方法指导试件制备、纳米压痕及结果分析,设定压人载荷分别为1、2、3、4、5mN,最大载荷保持时间为0、10、30、60s,分析测出的颌骨弹性模量(E),对载荷-深度曲线进行初步解析.结果:在人下颌骨的纳米压痕测试时,当压入载荷为3~5mN、最大载荷保持时间为10s及以上,所得测试结果对弹性模量值的影响较小.结论:本文确定了颌骨测试时推荐使用的压入载荷大小及最大载荷的保持时间,并应用纳米压痕测试法测试得到人下颌骨磨牙区皮质骨的平均弹性模量(E)值为18GPa.%Objective: Nano-indentation of bones recently has been further developed because of the materials and test techniques' improvement. We compared the latest articles and our tests with the early literatures about nano-indentation of bones, and made an argument. The aim of this paper was to reduce or eliminate some interference factors in the period of experiment and to determine whether changes in the max load and pause time are related to bone elastic modulus (E). The viscoelastic behavior of bones and load-displacement curve were also explained. Methods: A fresh mandibular bone was harvest and then cut into several sections to test by recommended nano-indentaion method. This method instructed specimen preparation, nano-indentaion and result analysis. Different Max loads at 1, 2, 3, 4, 5mN, and different pause time at 0, 10, 30, 60s, were set respectively and measured. Results: With a max load at 3~5mN and a pause time at 10s or more, the test could give a precise and repeatable elastic modulus. Our test method reduced the duration of specimen preparation and water loss, and might get nearer results as bones in internal environment. Conclusion: Our study measured

  2. Nanoindentation and AFM studies of PECVD DLC and reactively sputtered Ti containing carbon films

    Indian Academy of Sciences (India)

    A Pauschitz; J Schalko; T Koch; C Eisenmenger-Sittner; S Kvasnica; Manish Roy

    2003-10-01

    Amorphous carbon film, also known as DLC film, is a promising material for tribological application. It is noted that properties relevant to tribological application change significantly depending on the method of preparation of these films. These properties are also altered by the composition of the films. In view of this, the objective of the present work is to compare the nanoindentation and atomic force microscopy (AFM) study of diamond like carbon (DLC) film obtained by plasma enhanced chemical vapour deposition (PECVD) with the Ti containing amorphous carbon (Ti/-C : H) film obtained by unbalanced magnetron sputter deposition (UMSD). Towards that purpose, DLC and Ti/-C : H films are deposited on silicon substrate by PECVD and UMSD processes, respectively. The microstructural features and the mechanical properties of these films are evaluated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), nanoindentation and by AFM. The results show that the PECVD DLC film has a higher elastic modulus, hardness and roughness than the UMSD Ti/-C : H film. It also has a lower pull off force than Ti containing amorphous carbon film.

  3. Study of the mechanical properties of CeO{sub 2} layers with the nanoindentation technique

    Energy Technology Data Exchange (ETDEWEB)

    Roa, J.J., E-mail: joanjosep_roa@ub.ed [Centro DIOPMA, Departamento de Ciencia de los Materiales e Ingenieria Metalurgica, Facultad de Quimica, Universidad de Barcelona, C/Marti i Franques, 1, 08028, Barcelona (Spain); Gilioli, E.; Bissoli, F.; Pattini, F.; Rampino, S. [IMEM-CNR, Area delle Scienze 37/A, 43010 Fontanini-Parma (Italy); Capdevila, X.G.; Segarra, M. [Centro DIOPMA, Departamento de Ciencia de los Materiales e Ingenieria Metalurgica, Facultad de Quimica, Universidad de Barcelona, C/Marti i Franques, 1, 08028, Barcelona (Spain)

    2009-11-02

    The mechanical properties of CeO{sub 2} layers that are undoped or doped with other elements (e.g. Zr and Ta) are a topic of special interest specially in the manufacturing of superconductor buffer layers by pulsed electron deposition. Nowadays, the trend is to produce small devices (i.e. coated conductors), and the correct mechanical characterization is critical. In this sense, nanoindentation is a powerful technique widely employed to determine the mechanical properties of small volumes. In this study, the nanoindentation technique allow us determine the hardness (H) and Young's modulus (E) by sharp indentation of different buffer layers to explore the deposition process of CeO{sub 2} that is undoped or doped with Zr and Ta, and deposited on Ni-5%W at room temperature. This study was carried out on various samples at different ranges of applied loads (from 0.5 to 500 mN). Scanning electron microscopy images show no cracking for CeO{sub 2} doped with Zr, as the doping agent increases the toughness fracture of the CeO{sub 2} layer. This system, presents better mechanical stability than the other studied systems. Thus, the H for Zr-CeO{sub 2} is around 2.75 . 10{sup 6} Pa, and the elastic modulus calculated using the Bec et al. and Rar et al. models equals 249 . 10{sup 6} Pa and 235 . 10{sup 6} Pa respectively.

  4. Nanoindentation and micro-mechanical fracture toughness of electrodeposited nanocrystalline Ni-W alloy films

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, D.E.J., E-mail: david.armstrong@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH (United Kingdom); Haseeb, A.S.M.A. [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Roberts, S.G.; Wilkinson, A.J. [Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH (United Kingdom); Bade, K. [Institut fuer Mikrostrukturtechnik (IMT), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2012-04-30

    Nanocrystalline nickel-tungsten alloys have great potential in the fabrication of components for microelectromechanical systems. Here the fracture toughness of Ni-12.7 at.%W alloy micro-cantilever beams was investigated. Micro-cantilevers were fabricated by UV lithography and electrodeposition and notched by focused ion beam machining. Load was applied using a nanoindenter and fracture toughness was calculated from the fracture load. Fracture toughness of the Ni-12.7 at.%W was in the range of 1.49-5.14 MPa {radical}m. This is higher than the fracture toughness of Si (another important microelectromechanical systems material), but considerably lower than that of electrodeposited nickel and other nickel based alloys. - Highlights: Black-Right-Pointing-Pointer Micro-scale cantilevers manufactured by electro-deposition and focused ion beam machining. Black-Right-Pointing-Pointer Nanoindenter used to perform micro-scale fracture test on Ni-13at%W micro-cantilevers. Black-Right-Pointing-Pointer Calculation of fracture toughness of electrodeposited Ni-13at%W thin films. Black-Right-Pointing-Pointer Fracture toughness values lower than that of nanocrystalline nickel.

  5. Plastic deformation behavior of Fe–Co–B–Si–Nb–Cr bulk metallic glasses under nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.T.; Hong, S.H.; Lee, C.H. [HMC, Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 98 Gunja-dong, Gwangjin-gu, Seoul 143-747 (Korea, Republic of); Park, J.M., E-mail: jinman_park@hotmail.com [Materials Research Center, Samsung Advanced Institute of Technology (SAIT), San 14-1, Nongseo-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-712 (Korea, Republic of); Kim, T.W.; Lee, W.H. [HMC, Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 98 Gunja-dong, Gwangjin-gu, Seoul 143-747 (Korea, Republic of); Yim, H.I. [Department of Physics, Sookmyung Women’s University, Hyochangwongil 52, Yongsan-ku, Seoul 140-742 (Korea, Republic of); Kim, K.B., E-mail: kbkim@sejong.ac.kr [HMC, Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 98 Gunja-dong, Gwangjin-gu, Seoul 143-747 (Korea, Republic of)

    2014-02-25

    Highlights: • Additional Cr modulation of atomic structure of Fe-Co-B-Si-Nb BMGs. • An amount of free volume characterized by a combination of nanoindentation and AFM. • Free volume determined by height measurement of AFM after nanoindentation. -- Abstract: In this work, we investigate the effect of Cr addition on thermal properties and indentation behavior of Fe{sub 52}Co{sub 20−x}B{sub 20}Si{sub 4}Nb{sub 4}Cr{sub x} alloys with x = 0, 1, 3 and 5 at.%, respectively. Among all studied alloys, the Fe{sub 52}Co{sub 17}B{sub 20}Si{sub 4}Nb{sub 4}Cr{sub 3} bulk metallic glass (BMG) exhibits the highest thermal stability with large supercooled liquid region of 40 K and the pronounced plastic deformation features which is serrated flow (pop-in event) and significant pile-up of materials around indents. This demonstrates that the appropriate addition of Cr in Fe-based BMG can induce the internal atomic structure modulation and promote the mechanical softening, which are discussed in terms of free volume concept.

  6. In Situ TEM Nanoindentation Studies on Stress-Induced Phase Transformations in Metallic Materials

    Science.gov (United States)

    Liu, Y.; Wang, H.; Zhang, X.

    2016-01-01

    Although abundant phase transformations are in general thermally driven processes, there are many examples wherein stresses can induce phase transformations. Numerous in situ techniques, such as in situ x-ray diffraction and neutron diffraction, have been applied to reveal phase transformations. Recently, an in situ nanoindentation technique coupled with transmission electron microscopy demonstrated the capability to directly correlating stresses with phase transformations and microstructural evolutions at a submicron length scale. Here we briefly review in situ studies on stress-induced diffusional and diffusionless phase transformations in amorphous CuZrAl alloy and NiFeGa shape memory alloy. In the amorphous CuZrAl, in situ nanoindentation studies show that the nucleation of nanocrystals (a diffusional process) occurs at ultra-low stresses manifested by a prominent stress drop. In the NiFeGa shape memory alloy, two distinctive types of martensitic (diffusionless) phase transformations accompanied by stress plateaus are observed, including a reversible gradual phase transformation at low stress levels, and an irreversible abrupt phase transition at higher stress levels.

  7. Depth-sensing nano-indentation on a myelinated axon at various stages

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Wei-Chin; Liao, Jiunn-Der [Department of Materials Science and Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Lin, Chou-Ching K [Department of Neurology, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Ju, Ming-Shaung, E-mail: jdliao@mail.ncku.edu.tw [Department of Mechanical Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China)

    2011-07-08

    A nano-mechanical characterization of a multi-layered myelin sheath structure, which enfolds an axon and plays a critical role in the transmission of nerve impulses, is conducted. Schwann cells co-cultured in vitro with PC12 cells for various co-culture times are differentiated to form a myelinated axon, which is then observed using a transmission electron microscope. Three major myelination stages, with distinct structural characteristics and thicknesses around the axon, can be produced by varying the co-culture time. A dynamic contact module and continuous depth-sensing nano-indentation are used on the myelinated structure to obtain the load-on-sample versus measured displacement curve of a multi-layered myelin sheath, which is used to determine the work required for the nano-indentation tip to penetrate the myelin sheath. By analyzing the harmonic contact stiffness versus the measured displacement profile, the results can be used to estimate the three stages of the multi-layered structure on a myelinated axon. The method can also be used to evaluate the development stages of myelination or demyelination during nerve regeneration.

  8. Mechanical Deformation Induced in Si and GaN Under Berkovich Nanoindentation

    Directory of Open Access Journals (Sweden)

    Jian Sheng-Rui

    2007-01-01

    Full Text Available AbstractDetails of Berkovich nanoindentation-induced mechanical deformation mechanisms of single-crystal Si(100 and the metal-organic chemical-vapor deposition (MOCVD derived GaN thin films have been systematic investigated by means of micro-Raman spectroscopy and cross-sectional transmission electron microscopy (XTEM techniques. The XTEM samples were prepared by using focused ion beam (FIB milling to accurately position the cross-section of the nanoindented area. The behaviors of the discontinuities displayed in the loading and unloading segments of the load-displacement curves of Si and GaN thin films performed with a Berkovich diamond indenter tip were explained by the observed microstructure features obtained from XTEM analyses. According to the observations of micro-Raman and XTEM, the nanoindentation-induced mechanical deformation is due primarily to the generation and propagation of dislocations gliding along the pyramidal and basal planes specific to the hexagonal structure of GaN thin films rather than by indentation-induced phase transformations displayed in Si.

  9. Deformation mechanisms during nanoindentation of sodium borosilicate glasses of nuclear interest.

    Science.gov (United States)

    Kilymis, D A; Delaye, J-M

    2014-07-07

    In this paper we analyze results of Molecular Dynamics simulations of Vickers nanoindentation, performed for sodium borosilicate glasses of interest in the nuclear industry. Three glasses have been studied in their pristine form, as well as a disordered one that is analogous to the real irradiated glass. We focused in the behavior of the glass during the nanoindentation in order to reveal the mechanisms of deformation and how they are affected by microstructural characteristics. Results have shown a strong dependence on the SiO2 content of the glass, which promotes densification due to the open structure of SiO4 tetrahedra and also due to the strength of Si-O bonds. Densification for the glasses is primarily expressed by the relative decrease of the Si-O-Si and Si-O-B angles, indicating rotation of the structural units and decrease of free volume. The increase of alkali content on the other hand results to higher plasticity of the matrix and increased shear flow. The most important effect on the deformation mechanism of the disordered glasses is that of the highly depolymerized network that will also induce shear flow and, in combination with the increased free volume, will result in the decreased hardness of these glasses, as has been previously observed.

  10. Molecule Statistical Thermodynamics Simulation of Nanoindentation of Single Crystal Copper with EAM Potential

    Institute of Scientific and Technical Information of China (English)

    TAN Hao; WANG Hai-Ying; XIA Meng-Fen; KE Fu-Jiu; BAI Yi-Long

    2011-01-01

    The quasistatic nanoindentation process of a spherical indenter in a single crystal copper is investigated with the molecular statistical thermodynamics (MST) method based on the embedded atom method (EAM) potential.The indentation modulus obtained in the MST simulation is 129.9 GPa, which agrees well with the theoretical prediction (129 GPa). In the elastic regime, the obtained maximum displacement of the indenter is two times the contact depth and the contact area is qualitatively proportional to the contact depth, which agrees well with Hertzian elastic theory of contact. The MST simulation can reproduce the nucleation of dislocation as well.Moreover, the efficiency of the MST method is about 8 times higher than that of traditional MD simulations.%The quasistatic nanoindentation process of a spherical indenter in a single crystal copper is investigated with the molecular statistical thermodynamics(MST)method based on the embedded atom method(EAM)potential.The indentation modulus obtained in the MST simulation is 129.9 GPa, which agrees well with the theoretical prediction(129GPa).In the elastic regime, the obtained maximum displacement of the indenter is two times the contact depth and the contact area is qualitatively proportional to the contact depth, which agrees well with Hertzian elastic theory of contact.The MST simulation can reproduce the nucleation of dislocation as well.Moreover, the efficiency of the MST method is about 8 times higher than that of traditional MD simulations

  11. Effect of densification distribution on the Young's modulus of porous coatings after nano-indentation

    Institute of Scientific and Technical Information of China (English)

    Xiaojuan LU; Ping XIAO; Haiyan LI

    2012-01-01

    Nano-indentation of a porous ceramic coating leads to crushing and densification of the coating under the indenter.In this work,finite element simulations of indentation on the porous coating have been carried out to study the effect of the size and distribution of densification on Young's modulus measured by nano-indentation.Two totally different distribution patterns have been simulated in this work.In the case of gradient densification,the Young's modulus increased by 8.6% when the densification has occurred in the maximum influenced area.While the Young's modulus increased by 2% with a uniformed densification.Examinations of the cross-section of the coatings have suggested that the densification after the indentation is close to the second model.The measured Young's modulus could have differed by 2%.The effect of densification on the Young's modulus measured by using nano-indentation is strongly dependent on the densification patterns of the porous coating.

  12. NANOINDENTATION OF THIN-FILM-SUBSTRATE SYSTEM:DETERMINATION OF FILM HARDNESS AND YOUNG'S MODULUS

    Institute of Scientific and Technical Information of China (English)

    CHEN Shaohua; LIU Lei; WANG Tzuchiang

    2004-01-01

    In the present paper, the hardness and Young's modulus of fllm-substrate systems are determined by means of nanoindentation experiments and modified models. Aluminum film and two kinds of substrates, i.e. glass and silicon, are studied. Nanoindentation XP Ⅱ and continuous stiffness mode are used during the experiments. In order to avoid the influence of the Oliver and Pharr method used in the experiments, the experiment data are analyzed with the constant Young's modulus assumption and the equal hardness assumption. The volume fraction model (CZ model) proposed by Fabes et al. (1992) is used and modified to analyze the measured hardness. The method proposed by Doerner and Nix (DN formula) (1986) is modified to analyze the measured Young's modulus. Two kinds of modified empirical formula are used to predict the present experiment results and those in the literature, which include the results of two kinds of systems, i.e., a soft film on a hard substrate and a hard film on a soft substrate. In the modified CZ model, the indentation influence angle, ψ,is considered as a relevant physical parameter, which embodies the effects of the indenter tip radius,pile-up or sink-in phenomena and deformation of film and substrate.

  13. Nano-compression of carbon micro-balloons on a xp-nanoindenter

    Energy Technology Data Exchange (ETDEWEB)

    Gouadec, G.; Carlisle, K. (Kipp B.); Chawla, Krishan Kumar,; Koopman, M. (Mark); Gladysz, G. M. (Gary M.)

    2002-01-01

    Microballoons are thin hollow spheres that are bonded together with resins to form 'syntactic foam'. These foams exhibit very high specific compressive strength. Mechanical properties of the microballoons are integral to the mechanical properties of the syntactic foams and will also be useful in modeling of the system. This paper will present nano-compression results obtained for individual carbon microballoons (CMBs) tested between 5 and 50 mN on a XP nano-indentation device (MTS) customized with a special cylindrical tip. Details of the procedure will also be presented. CMBs ranging in diameter from 5 to 80 pm were randomly chosen for testing, which allowed for a statistical analysis (140 tests). Less than 25% of the CMBs were found to be nearly perfect spheres (from comparison between the 'horizontal' diameter measured with a microscope and the 'vertical' compressed diameter). CMBs smaller than 10 pm and greater than 50 pm were markedly ellipsoidal and about one third of the CMBs exhibited 'sequential' cracking, revealing the existence of flaws. SEM and optical microscopy of the foams revealed these flaws as either voids in the wall thickness or compartments in some CMBs. Conventional Berkovich nano-indentation was performed on segments of CMB walls after nanocompresseion and yielded a value of approximately 31 GPa for Young's modulus. The measured thickness was between 0.3 and 2.2 pm, showing no correlation with the diameter of the pristine CMBs.

  14. The role of proteoglycans in the nanoindentation creep behavior of human dentin.

    Science.gov (United States)

    Bertassoni, Luiz E; Kury, Matheus; Rathsam, Catherine; Little, Christopher B; Swain, Michael V

    2015-03-01

    Attempts to understand the mechanical behavior of dentin and other mineralized tissues have been primarily focused on the role of their more abundant matrix components, such as collagen and hydroxyapatite. The structural mechanisms endowing these biological materials with outstanding load bearing properties, however, remain elusive to date. Furthermore, while their response to deformation has been extensively studied, mechanisms contributing to their recovery from induced deformation remain poorly described in the literature. Here, we offer novel insights into the participation of proteoglycans (PG) and glycosaminoglycans (GAG) in regulating the nanoindentation creep deformation and recovery of mineralized and demineralized dentin. Accordingly, after the enzymatic digestion of either PGs and associated GAGs or only GAGs, the nanoindentation creep deformation of dentin increased significantly, while the relative recovery of both the mineralized and demineralized dentin dropped by 40-70%. In summary, our results suggest that PGs and GAGs may participate in a nanoscale mechanism that contributes significantly to the outstanding durability of dentin and possibly other mineralized tissues of similar composition.

  15. Towards the modeling of nanoindentation of virus shells: Do substrate adhesion and geometry matter?

    Science.gov (United States)

    Bousquet, Arthur; Dragnea, Bogdan; Tayachi, Manel; Temam, Roger

    2016-12-01

    Soft nanoparticles adsorbing at surfaces undergo deformation and buildup of elastic strain as a consequence of interfacial adhesion of similar magnitude with constitutive interactions. An example is the adsorption of virus particles at surfaces, a phenomenon of central importance for experiments in virus nanoindentation and for understanding of virus entry. The influence of adhesion forces and substrate corrugation on the mechanical response to indentation has not been studied. This is somewhat surprising considering that many single-stranded RNA icosahedral viruses are organized by soft intermolecular interactions while relatively strong adhesion forces are required for virus immobilization for nanoindentation. This article presents numerical simulations via finite elements discretization investigating the deformation of a thick shell in the context of slow evolution linear elasticity and in presence of adhesion interactions with the substrate. We study the influence of the adhesion forces in the deformation of the virus model under axial compression on a flat substrate by comparing the force-displacement curves for a shell having elastic constants relevant to virus capsids with and without adhesion forces derived from the Lennard-Jones potential. Finally, we study the influence of the geometry of the substrate in two-dimensions by comparing deformation of the virus model adsorbed at the cusp between two cylinders with that on a flat surface.

  16. Specimen Collection and Submission Manual

    Science.gov (United States)

    2016-06-01

    a validated test algorithm . If there is insufficient specimen volume for testing, there may be delays, and the request may be referred to management...Additional guidance on packing and shipping infectious substances can be found through American Society for Microbiology: http://www.asm.org...images/pdf/Clinical/ pack -ship-7-15-2011.pdf TR-16-161 DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. UNCLASSIFIED

  17. Fungal contaminants in cytopathology specimens

    Directory of Open Access Journals (Sweden)

    Prashant Sharma

    2014-02-01

    Full Text Available A pseudo-epidemic of environmental fungi, most likely by Fusarium spp., leading to inappropriate investigations for disseminated systemic mycosis is described. Subtle diagnostic clues, including the specimens affected, the nature of the host response, and the type of fungal elements noted helped to determine the nature of contaminants. The potential pitfall can be avoided by the knowledge of pertinent disease biology, prompt consultation for infectious diseases, and investigations of the potential environmental sources followed by source control.

  18. Single fiber push-out characterization of interfacial mechanical properties in unidirectional CVI-C/SiC composites by the nano-indentation technique

    Science.gov (United States)

    Zhang, Lifeng; Ren, Chengzu; Zhou, Changling; Xu, Hongzhao; Jin, Xinmin

    2015-12-01

    The characterization of interfaces in woven ceramic matrix composites is one of the most challenging problems in composite application. In this investigation, a new model material consisting of the chemical vapor infiltration unidirectional C/SiC composites with PyC fiber coating were prepared and evaluated to predict the interfacial mechanic properties of woven composites. Single fiber push-out/push-back tests with the Berkovich indenter were conducted on the thin sliced specimens using nano-indentation technique. To give a detailed illustration of the interfacial crack propagation and failure mechanism, each sector during the push-out process was analyzed at length. The test results show that there is no detectable difference between testing a fiber in a direct vicinity to an already tested fiber and testing a fiber in vicinity to not-pushed fibers. Moreover, the interface debonding and fiber sliding mainly occur at the PyC coating, and both the fiber and surrounding matrix have no plastic deformation throughout the process. Obtained from the load-displacement curve, the interfacial debonding strength (IDS) and friction stress (IFS) amount to, respectively, 35 ± 5 MPa and 10 ± 1 MPa. Based on the findings, the interfacial properties with PyC fiber coating can be predicted. Furthermore, it is expected to provide a useful guideline for the design, evaluation and optimal application of CVI-C/SiC.

  19. Development and testing of an integrated smart tool holder for four-component cutting force measurement

    Science.gov (United States)

    Xie, Zhengyou; Lu, Yong; Li, Jianguang

    2017-09-01

    Cutting force measurement is a significant requirement for monitoring and controlling the machining processes. Hence, various methods of measuring the cutting force have been proposed by many researchers. In this study, an innovative integrated smart tool holder system based on capacitive sensors is designed, constructed and tested, which is capable of measuring triaxial cutting force and a torque simultaneously in a wireless environment system. A standard commercial tool holder is modified to make itself be the force sensing element that has advantages of simple structure and easy machining. Deformable beams are created in the tool holder, and the tiny deformations of which used to calculate the four-component cutting force are detected by six high precision capacitive sensors. All the sensors and other electronics, like data acquisition and transmitting unit, and wireless power unit, are incorporated into the tool holder as a whole system. The device is intended to be used in a rotating spindle such as in milling and drilling processes. Eventually, the static and dynamic characteristics of the smart tool holder have been determined by a series of tests. Cutting tests have also been carried out and the results show it is stable and practical to measure the cutting force in milling and drilling processes.

  20. Position of document holder and work related risk factors for neck pain among computer users: a narrative review.

    Science.gov (United States)

    Ambusam, S; Baharudin, O; Roslizawati, N; Leonard, J

    2015-01-01

    Document holder is used as a remedy to address occupational neck pain among computer users. An understanding on the effects of the document holder along with other work related risk factors while working in computer workstation requires attention. A comprehensive knowledge on the optimal location of the document holder in computer use and associated work related factors that may contribute to neck pain reviewed in this article. A literature search has been conducted over the past 14 years based on the published articles from January 1990 to January 2014 in both Science Direct and PubMed databases. Medical Subject Headings (MeSH) keywords for search were neck muscle OR head posture OR muscle tension' OR muscle activity OR work related disorders OR neck pain AND/OR document location OR document holder OR source document OR copy screen holder.Document holder placed lateral to the screen was most preferred to reduce neck discomfort among occupational typists. Document without a holder was placed flat on the surface is least preferred. The head posture and muscle activity increases when the document is placed flat on the surface compared to when placed on the document holder. Work related factors such as static posture, repetitive movement, prolong sitting and awkward positions were the risk factors for chronic neck pain. This review highlights the optimal location for document holder for computer users to reduce neck pain. Together, the importance of work related risk factors for to neck pain on occupational typist is emphasized for the clinical management.

  1. [The Journey of a Surgeon Begins with a Camera-Holder].

    Science.gov (United States)

    Li, Hui

    2016-06-20

    The techniques of thoracic surgery has undergone evolutionary changes, and currently video-assisted thoracic surgery (VATS) has already been or is going to be the predominant procedure of various thoracic surgeries. The safe and artistic VATS with high quality is closely associated with the cooperation of camera-holder and the surgeon. If an excellent thoracotomy is the result of perfect integral cooperation of the brain, eyes, hands and the body of the surgeon, the camera-holder in VATS procedure, then, is responsible for the eyes of both the surgeons and himself. This is more meticulous and difficult than that for a single person's brain, eyes, hands and body. Meanwhile, an excellent camera-holder will undoubtedly become an excellent surgeon in the foreseeable future.

  2. A MODIFIED ALGORITHM FOR DEALING WITH HOLDER FRICTION BOUNDARY CONDITION IN SIMULATION OF SHEET METAL FORMING

    Institute of Scientific and Technical Information of China (English)

    Na Jingxin; Shen Guozhe; Liu Haipeng; Hu Ping

    2005-01-01

    This paper investigates the equivalent model for the friction boundary condition between blank and holder during sheet metal forming simulation, and proposes an equivalent algorithm, the thickness threshold value algorithm, for the first time based on thickness weighting.This algorithm assumes that the holder clearance is uniform during sheet metal forming; and the main reason for the unevenness of friction force distribution under the holder is that the uneven deformation of the blank leads to its uneven thickness distribution, which makes the local pressure on the blank distributed unevenly. The algorithm proposed in this paper can effectively simulate the influence of the unevenness on the forming process. Validity of this algorithm is verified by a comparison between the simulation results and the experimental ones for the drawing process of a car spring base.

  3. H(o)lder Norm Estimate for a Hilbert Transform in Hermitean Clifford Analysis

    Institute of Scientific and Technical Information of China (English)

    Ricardo ABREU-BLAYA; Juan BORY-REYES; Fred BRACKX; Hennie DE SCHEPPER

    2012-01-01

    A Hilbert transform for H(o)lder continuous circulant (2 × 2) matrix functions,on the dsummable (or fractal) boundary T of a Jordan domain Ω in R2n,has recently been introduced within the framework of Hermitean Clifford analysis.The main goal of the present paper is to estimate the H(o)lder norm of this Hermitean Hilbert transform.The expression for the upper bound of this norm is given in terms of the H(o)lder exponents,the diameter of T and a specific d-sum (d > d) of the Whitney decomposition of Ω.The result is shown to include the case of a more standard Hilbert transform for domains with left Ahlfors-David regular boundary.

  4. Reduction of gross hemolysis in catheter-drawn blood using Greiner Holdex tube holder.

    Science.gov (United States)

    Lippi, Giuseppe; Avanzini, Paola; Aloe, Rosalia; Cervellin, Gianfranco

    2013-01-01

    Blood collection through intravenous lines frequently causes spurious hemolysis. Due to specific structure, the tube holder Holdex (Greiner Bio-One GmbH, Kremsmuenster, Austria) is supposed to prevent erythrocyte injury in samples collected from catheters, so that we planned a specific study to support this hypothesis. Blood was collected from emergency department (ED) patients with 20-gauge catheter. In patients with odd order numbers, first and second tubes were collected with conventional holder (BD Vacutainer One Use Holder, Becton Dickinson, Milan, Italy) and the third with Holdex, whereas in even patients first and second tubes were drawn with Holdex and the third using BD Vacutainer One Use Holder. The first tube was discarded, whereas the second and third were centrifuged and serum was tested for potassium, lactate dehydrogenase (LD) and hemolysis index. The final study population consisted in 60 ED patients. Concentrations of potassium (4.25 vs. 4.16 mmol/L; P = 0.031), LD (498 vs. 459 U/L; P = 0.039) and cell-free hemoglobin (0.42 vs. 0.22 g/L; P = 0.042) were higher in samples collected with BD Vacutainer One Use Holder than with Holdex. The mean bias of cell-free hemoglobin was -0.4 g/L in samples collected with Holdex. Although the frequency of samples with cell-free hemoglobin > 0.5 g/L was identical (17/60 vs. 17/60; P = 1.00), the frequency of those with concentrations > 3.0 g/L was higher using BD Vacutainer One Use Holder than Holdex (4/60 vs. 0/60; P = 0.042). The use of Holdex for drawing blood from intravenous lines may be effective for reducing gross hemolysis.

  5. Reduction of gross hemolysis in catheter-drawn blood using Greiner Holdex® tube holder

    Science.gov (United States)

    Lippi, Giuseppe; Avanzini, Paola; Aloe, Rosalia; Cervellin, Gianfranco

    2013-01-01

    Introduction: Blood collection through intravenous lines frequently causes spurious hemolysis. Due to specific structure, the tube holder Holdex® (Greiner Bio-One GmbH, Kremsmuenster, Austria) is supposed to prevent erythrocyte injury in samples collected from catheters, so that we planned a specific study to support this hypothesis. Materials and methods: Blood was collected from emergency department (ED) patients with 20-gauge catheter. In patients with odd order numbers, first and second tubes were collected with conventional holder (BD Vacutainer One Use Holder, Becton Dickinson, Milan, Italy) and the third with Holdex, whereas in even patients first and second tubes were drawn with Holdex and the third using BD Vacutainer One Use Holder. The first tube was discarded, whereas the second and third were centrifuged and serum was tested for potassium, lactate dehydrogenase (LD) and hemolysis index. Results: The final study population consisted in 60 ED patients. Concentrations of potassium (4.25 vs. 4.16 mmol/L; P = 0.031), LD (498 vs. 459 U/L; P = 0.039) and cell-free hemoglobin (0.42 vs. 0.22 g/L; P = 0.042) were higher in samples collected with BD Vacutainer One Use Holder than with Holdex. The mean bias of cell-free hemoglobin was −0.4 g/L in samples collected with Holdex. Although the frequency of samples with cell-free hemoglobin > 0.5 g/L was identical (17/60 vs. 17/60; P = 1.00), the frequency of those with concentrations >3.0 g/L was higher using BD Vacutainer One Use Holder than Holdex (4/60 vs. 0/60; P = 0.042). Conclusions: The use of Holdex for drawing blood from intravenous lines may be effective for reducing gross hemolysis. PMID:24266299

  6. Nanoindentation study of the combined effects of crystallography, heat treatment and exposure to high-flux deuterium plasma in tungsten

    NARCIS (Netherlands)

    Zayachuk, Y.; Armstrong, D. E. J.; Bystrov, K.; van Boxel, S.; Morgan, T.; Roberts, S. G.

    2017-01-01

    Tungsten samples were heat-treated to achieve partial recrystallization and exposed to high ion flux deuterium plasma at different temperatures and fluences. Continuous stiffness nanoindentation measurements of near-surface hardness were performed in the grains of specific annealing states and of sp

  7. Nanoindentation of Teeth-A Review%牙齿的纳米压痕技术综述

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper reviews some of the nanoindentation research that has been done on teeth and discusses the usefulness of this technique in studying the structure-property-function relationship at the micro and nanometer scale. In particular, examples on the use of nanoindentation technique in investigating the effects of cleansing and bleaching agents as well as drinks on the micro- and nanostructures and mechanical properties of teeth are highlighted. Although nanoindentation on teeth is a relatively new area of research, it provides an excellent way of probing and relating the structures and mechanical properties of teeth at the submicron and nanometer scales that were previously not possible but which can now greatly benefit dental research. For example, a nanoindenter with a high resolution imaging capability can help to elucidate the mechanisms with which certain diseases can damage and compromise the structural integrity of teeth at the micro- and nanometer scale. With this information, clinicians and researchers can then work towards how best to tackle these problems or even preventing them.

  8. Strain rate sensitivity of nanoindentation creep in an AlCoCrFeNi high-entropy alloy

    Science.gov (United States)

    Jiao, Z. M.; Wang, Z. H.; Wu, R. F.; Qiao, J. W.

    2016-09-01

    Creep behaviors of an AlCoCrFeNi high-entropy alloy with the body-centered cubic structure were investigated by nanoindentation. The enhanced strain gradient induced by higher strain rate leads to decreased strain rate sensitivity during creep process. The present alloy exhibits excellent creep resistance, mainly due to its large entropy of mixing and highly distorted lattice structure.

  9. Design and burn-up analyses of new type holder for silicon neutron transmutation doping.

    Science.gov (United States)

    Komeda, Masao; Arai, Masaji; Tamai, Kazuo; Kawasaki, Kozo

    2016-07-01

    We have developed a new silicon irradiation holder with a neutron filter to increase the irradiation efficiency. The neutron filter is made of an alloy of aluminum and B4C particles. We fabricated a new holder based on the results of design analyses. This filter has limited use in applications requiring prolonged use due to a decrease in the amount of (10)B in B4C particles. We investigated the influence of (10)B reduction on doping distribution in a silicon ingot by using the Monte Carlo Code MVP. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Real-time 3D visual tracking of laparoscopic instruments for robotized endoscope holder.

    Science.gov (United States)

    Zhao, Zijian

    2014-01-01

    Robotized endoscope holder in laparoscopic surgeries allows surgeons to control the endoscope without the assistants' intervention. In this paper, a new method is proposed for the automatic 3D-tracking of laparoscopic instruments in real-time to provide more convenient interactions between surgeons and the robotized endoscope holder. The method is based on the 3D position measurements of the insertion points of the instruments and the strip markers, combined with the depth estimation of the instruments. The results of our experiments show that our method is fast and robust in the simulated laparoscopic surgeries.

  11. A sample holder for in-house X-ray powder diffraction studies of protein powders

    DEFF Research Database (Denmark)

    Frankær, Christian Grundahl; Harris, Pernille; Ståhl, Kenny

    2011-01-01

    A sample holder for handling samples of protein for in-house X-ray powder diffraction (XRPD) analysis has been made and tested on lysozyme. The use of an integrated pinhole reduced the background, and good signal-to-noise ratios were obtained from only 7 l of sample, corresponding to approximately...... 2-3 mg of dry protein. The sample holder is further adaptable to X-ray absorption spectroscopy (XAS) measurements. Both XRPD and XAS at the Zn K-edge were tested with hexameric Zn insulin....

  12. Development and validation of a novel data analysis procedure for spherical nanoindentation

    Science.gov (United States)

    Pathak, Siddhartha

    This dissertation presents a novel approach for converting the raw load-displacement data measured in spherical nanoindentation into much more meaningful indentation stress-strain curves. This new method entails a novel definition of the indentation strain and a new procedure for establishing the effective zero point in the raw dataset---both with and without the use of the continuous stiffness measurement (CSM) data. The concepts presented here have been validated by simulations and experiments on isotropic metallic samples of aluminum and tungsten. It is demonstrated that these new indentation stress-strain curves accurately capture the loading and unloading elastic moduli, the indentation yield points, as well as the post-yield characteristics in the tested samples. Subsequently this approach has been applied on a wide range of material systems including metals, carbon nanotubes (CNTs), ceramics and bone. In metals, these data analysis techniques have been highly successful in explaining several of the surface preparation artifacts typically encountered during nanoindentation measurements. This approach has also been extended to anisotropic polycrystalline samples, where a judicious combination of Orientation Imaging Microscopy (OIM) and nanoindentation were used to estimate, for the first time, the changes in slip resistance in deformed grains of Fe-3%Si steel. Similar studies on dense CNT brushes, with ˜10 times higher density than CNT brushes produced by other methods, demonstrate the higher modulus (˜17-20 GPa) and orders of magnitude higher resistance to buckling in these brushes than vapor phase deposited CNT brushes or carbon walls, showing their promise for energy-absorbing coatings. Even for a complex hierarchical material system like bone, these techniques have elucidated trends in the elastic and yield behavior at the lamellar level in the femora (thigh bone) of different inbred mouse strains. Thus bone with a higher mineral-to-matrix ratio

  13. Comparison of the mechanical properties of NiTi/Cu bilayer by nanoindentation and tensile test: molecular dynamics simulation

    Science.gov (United States)

    Fazeli, Sara; Vahedpour, Morteza; Khatiboleslam Sadrnezhaad, Sayed

    2016-12-01

    Molecular dynamics simulation was used to study of mechanical properties of NiTi/Cu bilayer by nanoindentation and tensile testing. A comparison has been made among mechanical properties measured and plastic deformation process at different copper thickness during nanoindnetation and tensile test of the samples. Embedded atom method potentials for describing of inter-atomic interaction and Nose-Hoover thermostat and barostat are employed in the simulation at 400 K. The results showed that as the copper film thickness decreased, the maximum load and hardness values increased during nanoindetation. Saha and Nix model is used to describe reduced young’s modulus behaviour of the bilayer system through nanoindentation. A good agreement among calculated reduced elastic modulus by nanoindentation test and young’s modulus behaviour via tensile test have been obtained. The ‘incoherent interface’ in both of nanoindentation test and tensile testing is one of the governing factors for the dislocation propagation, which resulted in significant strengthening of the bilayer. It was observed that during tensile test, only copper layers were necked and fractured in all of samples. However, the present study seeks to examine the effect of film thickness on the free energy values that is obtained using Jarzynski’s equality during nanoindentation. As the copper film thickness was decreased, the free energy difference increased. According to both techniques, the thin film copper thickness provides lower number of nucleation locations resulting in the higher value of yield strength, hardness and free energy difference during nanoindenation. Mechanical properties of bilayer systems are improved with decreasing of copper film thickness. However, it specifies that strengths of all bilayer systems have prominent increase in young’s modulus in compared to the pure NiTi.

  14. Spherical nanoindentation of proton irradiated 304 stainless steel: A comparison of small scale mechanical test techniques for measuring irradiation hardening

    Science.gov (United States)

    Weaver, Jordan S.; Pathak, Siddhartha; Reichardt, Ashley; Vo, Hi T.; Maloy, Stuart A.; Hosemann, Peter; Mara, Nathan A.

    2017-09-01

    Experimentally quantifying the mechanical effects of radiation damage in reactor materials is necessary for the development and qualification of new materials for improved performance and safety. This can be achieved in a high-throughput fashion through a combination of ion beam irradiation and small scale mechanical testing in contrast to the high cost and laborious nature of bulk testing of reactor irradiated samples. The current work focuses on using spherical nanoindentation stress-strain curves on unirradiated and proton irradiated (10 dpa at 360 °C) 304 stainless steel to quantify the mechanical effects of radiation damage. Spherical nanoindentation stress-strain measurements show a radiation-induced increase in indentation yield strength from 1.36 GPa to 2.72 GPa and a radiation-induced increase in indentation work hardening rate of 10 GPa-30 GPa. These measurements are critically compared against Berkovich nanohardness, micropillar compression, and micro-tension measurements on the same material and similar grain orientations. The ratio of irradiated to unirradiated yield strength increases by a similar factor of 2 when measured via spherical nanoindentation or Berkovich nanohardness testing. A comparison of spherical indentation stress-strain curves to uniaxial (micropillar and micro-tension) stress-strain curves was achieved using a simple scaling relationship which shows good agreement for the unirradiated condition and poor agreement in post-yield behavior for the irradiated condition. The disagreement between spherical nanoindentation and uniaxial stress-strain curves is likely due to the plastic instability that occurs during uniaxial tests but is absent during spherical nanoindentation tests.

  15. Hydraulically Driven Grips For Hot Tensile Specimens

    Science.gov (United States)

    Bird, R. Keith; Johnson, George W.

    1994-01-01

    Pair of grips for tensile and compressive test specimens operate at temperatures up to 1,500 degrees F. Grips include wedges holding specimen inside furnace, where heated to uniform temperature. Hydraulic pistons drive wedges, causing them to exert clamping force. Hydraulic pistons and hydraulic fluid remain outside furnace, at room temperature. Cooling water flows through parts of grips to reduce heat transferred to external components. Advantages over older devices for gripping specimens in high-temperature tests; no need to drill holes in specimens, maintains constant gripping force on specimens, and heated to same temperature as that of specimen without risk of heating hydraulic fluid and acuator components.

  16. Tubulin bond energies and microtubule biomechanics determined from nanoindentation in silico

    CERN Document Server

    Kononova, Olga; Theisen, Kelly E; Marx, Kenneth A; Dima, Ruxandra I; Ataullakhanov, Fazly I; Grishchuk, Ekaterina L; Barsegov, Valeri

    2015-01-01

    Microtubules, the primary components of the chromosome segregation machinery, are stabilized by longitudinal and lateral non-covalent bonds between the tubulin subunits. However, the thermodynamics of these bonds and the microtubule physico-chemical properties are poorly understood. Here, we explore the biomechanics of microtubule polymers using multiscale computational modeling and nanoindentations in silico of a contiguous microtubule fragment. A close match between the simulated and experimental force-deformation spectra enabled us to correlate the microtubule biomechanics with dynamic structural transitions at the nanoscale. Our mechanical testing revealed that the compressed MT behaves as a system of rigid elements interconnected through a network of lateral and longitudinal elastic bonds. The initial regime of continuous elastic deformation of the microtubule is followed by the transition regime, during which the microtubule lattice undergoes discrete structural changes, which include first the reversib...

  17. Nanostructured surfaces yield earlier: Molecular dynamics study of nanoindentation into adatom islands

    Science.gov (United States)

    Ziegenhain, Gerolf; Urbassek, Herbert M.

    2010-04-01

    Using molecular-dynamics simulation we investigate nanoindentation into an fcc metal surface covered by an adatom island. Small islands are pushed into the solid and transported away by prismatic dislocation loops, and no defects remain under the indenter; thereafter indentation proceeds as for a flat surface. For large islands, the island boundaries do not influence indentation. Most interesting is the intermediate case, where the island size is comparable to the contact radius of the indenter at the onset of plasticity. Here plasticity starts immediately at the surface under the weakest step edges bounding the island. The dislocations are pinned to the step edges and dislocation activity remains localized under the island. For this intermediate case, the surface is weakest and yields earliest.

  18. Evolution of metastable phases in silicon during nanoindentation: mechanism analysis and experimental verification

    Energy Technology Data Exchange (ETDEWEB)

    Mylvaganam, K [Centre for Advanced Materials Technology, University of Sydney, NSW 2006 (Australia); Zhang, L C [School of Mechanical and Manufacturing Engineering, University of New South Wales, NSW 2052 (Australia); Eyben, P; Vandervorst, W [IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Mody, J, E-mail: k.mylvaganam@usyd.edu.a, E-mail: Liangchi.zhang@unsw.edu.a, E-mail: eyben@imec.b, E-mail: jamody@imec.b, E-mail: vdvorst@imec.b [KU Leuven, Electrical Engineering Department, INSYS, Kasteelpark Arenberg 10, B-3001 Leuven (Belgium)

    2009-07-29

    This paper explores the evolution mechanisms of metastable phases during the nanoindentation on monocrystalline silicon. Both the molecular dynamics (MD) and the in situ scanning spreading resistance microscopy (SSRM) analyses were carried out on Si(100) orientation, and for the first time, experimental verification was achieved quantitatively at the same nanoscopic scale. It was found that under equivalent indentation loads, the MD prediction agrees extremely well with the result experimentally measured using SSRM, in terms of the depth of the residual indentation marks and the onset, evolution and dimension variation of the metastable phases, such as {beta}-Sn. A new six-coordinated silicon phase, Si-XIII, transformed directly from Si-I was discovered. The investigation showed that there is a critical size of contact between the indenter and silicon, beyond which a crystal particle of distorted diamond structure will emerge in between the indenter and the amorphous phase upon unloading.

  19. Origin of a Nanoindentation Pop-in Event in Silicon Crystal.

    Science.gov (United States)

    Abram, R; Chrobak, D; Nowak, R

    2017-03-03

    The Letter concerns surface nanodeformation of Si crystal using atomistic simulation. Our results account for both the occurrence and absence of pop-in events during nanoindentation. We have identified two distinct processes responsible for indentation deformation based on load-depth response, stress-induced evolution of crystalline structure and surface profile. The first, resulting in a pop-in, consists of the extrusion of the crystalline high pressure Si-III/XII phase, while the second, without a pop-in, relies on a flow of amorphized Si to the crystal surface. Of particular interest to silicon technology will be our clarification of the interplay among amorphization, crystal-to-crystal transition, and extrusion of transformed material to the surface.

  20. Molecular Dynamics for Elastic and Plastic Deformation of a Single-Walled Carbon Nanotube Under Nanoindentation

    Institute of Scientific and Technical Information of China (English)

    FANG Te-Hua; JIAN Sheng-Rui; CHUU Der-San

    2004-01-01

    @@ Mechanical characteristics of a suspended (10, 10) single-walled carbon nanotube (SWCNT) during atomic force microscopy (AFM) nanoindentation are investigated at different temperatures by molecular dynamics simulations.The results indicate that the Young modulus of the (10, 10) SWCNT under temperatures of 300-600K is 1.2-1.3 TPa. As the temperature increases, the Young modulus of the SWCNT increases, but the axial strain of the SWCNT decreases. The strain-induced spontaneous formation of the Stone-Wales defects and the rippled behaviour under inhomogeneous stress are studied. The rippled behaviour of the SWCNT is enhanced with the increasing axial strain. The adhesive phenomenon between the probe and the nanotube and the elastic recovery of the nanotube during the retraction are also investigated.

  1. Nanoindentation of hcp metals: a comparative simulation study of the evolution of dislocation networks

    Science.gov (United States)

    Alabd Alhafez, Iyad; Ruestes, Carlos J.; Gao, Yu; Urbassek, Herbert M.

    2016-01-01

    Using molecular dynamics simulation, we study the nanoindentation of three hcp metals: Mg, Ti, and Zr. Both the basal and two prismatic surface planes are considered. We focus on the characterization of the plasticity generated in the crystal. The similarities to, and the differences from, the behavior of the more commonly investigated fcc and bcc metals are highlighted. We find that hcp metals show a larger variety than the fcc and bcc metals studied up until now. The prolific emission of prismatic loops can lead to extended plastic zones. The size of the plastic zone is quantified by the ratio f of the plastic zone radius to the radius of the contact area. We find values of between 1.6 (an almost collapsed zone) and >5 in the latter case, complex dislocation networks build up which are extended in the direction of easy glide.

  2. In situ nanoindentation study on plasticity and work hardening in aluminium with incoherent twin boundaries.

    Science.gov (United States)

    Bufford, D; Liu, Y; Wang, J; Wang, H; Zhang, X

    2014-09-10

    Nanotwinned metals have been the focus of intense research recently, as twin boundaries may greatly enhance mechanical strength, while maintaining good ductility, electrical conductivity and thermal stability. Most prior studies have focused on low stacking-fault energy nanotwinned metals with coherent twin boundaries. In contrast, the plasticity of twinned high stacking-fault energy metals, such as aluminium with incoherent twin boundaries, has not been investigated. Here we report high work hardening capacity and plasticity in highly twinned aluminium containing abundant Σ3{112} incoherent twin boundaries based on in situ nanoindentation studies in a transmission electron microscope and corresponding molecular dynamics simulations. The simulations also reveal drastic differences in deformation mechanisms between nanotwinned copper and twinned aluminium ascribed to stacking-fault energy controlled dislocation-incoherent twin boundary interactions. This study provides new insight into incoherent twin boundary-dominated plasticity in high stacking-fault energy twinned metals.

  3. Biomechanical Analysis of Hearing in Whales Using Nanoindentation and the Finite Element Method

    Science.gov (United States)

    Tubelli, Andrew A.; Zosuls, Aleks; Ketten, Darlene R.; Mountain, David C.

    2011-11-01

    The detailed biomechanics of hearing in baleen whales are almost entirely unknown. As a first step to predicting the audiogram for these species, a linear three-dimensional finite-element model of the minke whale (Balaenoptera acutorostrata) middle ear was developed. A reconstruction of the ear was made from CT scans and imported into a finite element solver. Young's modulus of the bone was estimated via nanoindentation. The middle-ear transfer function was estimated by applying a pressure to the glove finger (the thick, everted equivalent of the tympanic membrane) with velocity calculated at the stapes footplate. It was found that the most sensitive frequencies corresponded with vocalization frequencies. For all frequencies tested, the malleus-incus complex flexed about the anterior process of the malleus and the stapes rotated within the oval window. Results indictae that finite element modeling is a useful approach for studying the mechanics of hearing in species that are difficult to study in vivo.

  4. Nanoindentation study of ferrite–martensite dual phase steels developed by a new thermomechanical processing

    Energy Technology Data Exchange (ETDEWEB)

    Mazaheri, Yousef, E-mail: y.mazaheri@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Faculty of Engineering, Bu-Ali Sina University, Hamedan 65178-38695 (Iran, Islamic Republic of); Kermanpur, Ahmad; Najafizadeh, Abbas [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2015-07-15

    Dual phase (DP) steels consisting different volume fractions of ferrite and martensite and different ferrite grain size were produced by a new route utilizing cold-rolling and subsequent intercritical annealing of ferrite/martensite duplex starting structure at 770 °C for different times. Scanning electron microscopy has been supplemented by nanoindentation and tensile test to follow microstructural changes and their correlations to the variation in phase's hardness and mechanical properties. The results showed that longer holding times resulted in coarser and softer ferrite grains in DP microstructures. Martensite nanohardness variation with holding time is related to change in its carbon content. Mechanical properties such as strength, elongation and toughness are well correlated with the martensite/ferrite hardness ratio.

  5. Nanoindentation study of electrodeposited Ag thin coating: An inverse calculation of anisotropic elastic-plastic properties

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Guang; Sun, Xin; Wang, Yuxin; Tay, See Leng; Gao, Wei

    2017-01-01

    A new inverse method was proposed to calculate the anisotropic elastic-plastic properties (flow stress) of thin electrodeposited Ag coating utilizing nanoindentation tests, previously reported inverse method for isotropic materials and three-dimensional (3-D) finite element analyses (FEA). Indentation depth was ~4% of coating thickness (~10 μm) to avoid substrate effect and different indentation responses were observed in the longitudinal (L) and the transverse (T) directions. The estimated elastic-plastic properties were obtained in the newly developed inverse method by matching the predicted indentation responses in the L and T directions with experimental measurements considering indentation size effect (ISE). The results were validated with tensile flow curves measured from free-standing (FS) Ag film. The current method can be utilized to characterize the anisotropic elastic-plastic properties of coatings and to provide the constitutive properties for coating performance evaluations.

  6. Nanoindentation study on Gd-deposited YBaCuO superconductor

    Indian Academy of Sciences (India)

    F Yilmaz; O Uzun; U Kolemen; M F Kilicaslan; N Basman; S Ergen; K Ozturk; E Yanmaz

    2013-12-01

    Nanoindentation technique was used to characterize the mechanical properties of Gd-deposited bulk YBaCuO superconductors fabricated by solid-state reaction method. In order to determine the hardness and reduced modulus of the samples, load-displacement data were analysed by using the Oliver–Pharr method. The hardness values exhibited significant peak load-dependence especially at lower peak loads, while the reduced modulus values were found to be nearly constant at studied loading range. In order to find true hardness of the samples, the peak load-dependency of hardness was analysed by using Meyer’s law,minimum resistance model, elastic/plastic deformation model, energy balance model, Nix–Gao model and Mukhopadhyay approach. Of the aforementioned models, energy balance model and Mukhopadhyay approach were found to be the most effective models to explain the load-dependency of hardness.

  7. Nanoindentation of BaTiO{sub 3}: dislocation nucleation and mechanical twinning

    Energy Technology Data Exchange (ETDEWEB)

    Gaillard, Y; Anglada, M [Department of Materials Science and Metallurgy (CMEM), Universitat Politecnica de Catalunya, Avda. Diagonal 647 (ETSEIB), 08028 Barcelona (Spain); MacIas, A Hurtado [Centro de Investigacion en Materiales Avanzados, SC, Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua, 31109 (Mexico); Munoz-Saldana, J; Trapaga, G, E-mail: jmunoz@qro.cinvestav.m [Centro de Investigacion y Estudios Avanzados del IPN, Unidad Queretaro Apdo, Postal 1-798, 76001 Queretaro, Qro. (Mexico)

    2009-04-21

    This paper presents a study of the deformation mechanisms of barium titanate under nanoindentation. The (0 0 1) and (1 1 0) crystallographic orientations of BaTiO{sub 3} giant grains were indented and critical mean contact pressures for dislocation nucleation were extracted from the indentation curves. The orientation of the dislocation slip lines was identified by atomic force microscopy, showing that the (1 1 0){l_brace}1 1 0{r_brace} glide systems were activated. Twin bands, observed on both orientations, also occur on the {l_brace}1 1 0{r_brace} habit planes and actively participate in the accommodation of the plastic deformation. Furthermore, dislocation pile-ups introduced by spherical indentations have shown a close relation between dislocations and twinning formation.

  8. Nanomechanical characterization of nanostructured bainitic steel: Peak Force Microscopy and Nanoindentation with AFM

    Science.gov (United States)

    Morales-Rivas, Lucia; González-Orive, Alejandro; Garcia-Mateo, Carlos; Hernández-Creus, Alberto; Caballero, Francisca G.; Vázquez, Luis

    2015-01-01

    The full understanding of the deformation mechanisms in nanostructured bainite requires the local characterization of its mechanical properties, which are expected to change from one phase, bainitic ferrite, to another, austenite. This study becomes a challenging process due to the bainitic nanostructured nature and high Young’s modulus. In this work, we have carried out such study by means of the combination of AFM-based techniques, such as nanoindentation and Peak Force Quantitative Nanomechanical Mapping (PF-QNM) measurements. We have addressed critically the limits and advantages of these techniques and been able to measure some elastoplastic parameters of both phases. Specifically, we have analyzed by PF-QNM two nanostructured bainitic steels, with a finer and a coarser structure, and found that both phases have a similar Young’s modulus. PMID:26602631

  9. Fracture characterization in patterned thin films by cross-sectional nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Ocana, I. [CEIT and TECNUN (University of Navarra), P. Manuel Lardizabal 15, 20018 San Sebastian (Spain); Molina-Aldareguia, J.M. [CEIT and TECNUN (University of Navarra), P. Manuel Lardizabal 15, 20018 San Sebastian (Spain); Gonzalez, D. [CEIT and TECNUN (University of Navarra), P. Manuel Lardizabal 15, 20018 San Sebastian (Spain); Elizalde, M.R. [CEIT and TECNUN (University of Navarra), P. Manuel Lardizabal 15, 20018 San Sebastian (Spain)]. E-mail: relizalde@ceit.es; Sanchez, J.M. [CEIT and TECNUN (University of Navarra), P. Manuel Lardizabal 15, 20018 San Sebastian (Spain); Martinez-Esnaola, J.M. [CEIT and TECNUN (University of Navarra), P. Manuel Lardizabal 15, 20018 San Sebastian (Spain); Gil Sevillano, J. [CEIT and TECNUN (University of Navarra), P. Manuel Lardizabal 15, 20018 San Sebastian (Spain); Scherban, T.. E-mail: Tracey_Scherban@Hotmail.com; Pantuso, D. [Logic Technology Development, Intel Corporation, Hillsboro, OR 97124 (United States); Sun, B. [Logic Technology Development, Intel Corporation, Hillsboro, OR 97124 (United States); Xu, G. [Logic Technology Development, Intel Corporation, Hillsboro, OR 97124 (United States); Miner, B. [Logic Technology Development, Intel Corporation, Hillsboro, OR 97124 (United States); He, J. [Logic Technology Development, Intel Corporation, Hillsboro, OR 97124 (United States); Maiz, J. [Logic Technology Development, Intel Corporation, Hillsboro, OR 97124 (United States)

    2006-08-15

    A testing technique based on cross-sectional nanoindentation has been used to assess the mechanical reliability of interconnect structures. A Berkovich indenter was used to initiate fracture in a silicon substrate and cracks propagated through the structure. To better control crack growth and to convert the problem into two dimensions, a trench parallel to the indentation surface was previously machined using a focused ion beam. The crack lengths obtained for different material systems in the interconnect structure correlate well with the fracture energies measured for the same materials in blanket films. Finite element model simulations incorporating cohesive elements have been used to model the fracture processes and to explain the different cracking behaviour observed.

  10. Nanoindentation of ultra-hard cBN films: A molecular dynamics study

    Science.gov (United States)

    Huang, Cheng; Peng, Xianghe; Fu, Tao; Zhao, Yinbo; Feng, Chao; Lin, Zijun; Li, Qibin

    2017-01-01

    Cubic Boron nitride (cBN) exhibits excellent mechanical properties including high strength, hardness and thermal resistance, etc. We optimized the parameters in the Tersoff interatomic potential for cBN based on its cohesive energy, lattice parameter, elastic constants, surface energy and stacking fault energy. We performed with molecular dynamics (MD) simulations the nanoindentation on the (001) and (111) surface of monocrystalline cBN thin films to study the deformation mechanisms and the effects of temperature and substrate orientation. It was found that during the indentation plastic deformation is mainly stress-induced slips of dislocations along {111} orientations. It was also found that the hardness of cBN depends strongly on temperature, and the capability of plastic deformation is enhanced with the increase of temperature.

  11. Nanoscale elastic modulus of single horizontal ZnO nanorod using nanoindentation experiment

    Science.gov (United States)

    Soomro, Muhammad Yousuf; Hussain, Ijaz; Bano, Nargis; Broitman, Esteban; Nur, Omer; Willander, Magnus

    2012-02-01

    We measure the elastic modulus of a single horizontal ZnO nanorod [NR] grown by a low-temperature hydrothermal chemical process on silicon substrates by performing room-temperature, direct load-controlled nanoindentation measurements. The configuration of the experiment for the single ZnO NR was achieved using a focused ion beam/scanning electron microscope dual-beam instrument. The single ZnO NR was positioned horizontally over a hole on a silicon wafer using a nanomanipulator, and both ends were bonded with platinum, defining a three-point bending configuration. The elastic modulus of the ZnO NR, extracted from the unloading curve using the well-known Oliver-Pharr method, resulted in a value of approximately 800 GPa. Also, we discuss the NR creep mechanism observed under indentation. The mechanical behavior reported in this paper will be a useful reference for the design and applications of future nanodevices.

  12. Elastic modulus and hardness of cortical and trabecular bovine bone measured by nanoindentation

    Institute of Scientific and Technical Information of China (English)

    WANG X J; CHEN X B; HODGSON P D; WEN C E

    2006-01-01

    The elastic modulus and hardness of several microstructure components of dry bovine vertebrae and tibia have been investigated in the longitude and transverse directions using nanoindentation. The elastic modulus for the osteons and the interstitial lamellae in the longitude direction were found to be (24.7±2.5) GPa and (30.1±2.4) GPa. As it's difficult to distinguish osteons from interstitial lamellae in the transverse direction,the average elastic modulus for cortical bovine bone in the transverse direction was (19.8±1.6) GPa. The elastic modulus for trabecular bone in the longitude and transverse direction were (20±2) GPa and (14.7±1.9) GPa respectively. The hardness also varied among the microstructure components in the range of 0.41-0.89 GPa. Analyses of variance show that the values are significantly different.

  13. Nanomechanical characterization of nanostructured bainitic steel: Peak Force Microscopy and Nanoindentation with AFM.

    Science.gov (United States)

    Morales-Rivas, Lucia; González-Orive, Alejandro; Garcia-Mateo, Carlos; Hernández-Creus, Alberto; Caballero, Francisca G; Vázquez, Luis

    2015-11-25

    The full understanding of the deformation mechanisms in nanostructured bainite requires the local characterization of its mechanical properties, which are expected to change from one phase, bainitic ferrite, to another, austenite. This study becomes a challenging process due to the bainitic nanostructured nature and high Young's modulus. In this work, we have carried out such study by means of the combination of AFM-based techniques, such as nanoindentation and Peak Force Quantitative Nanomechanical Mapping (PF-QNM) measurements. We have addressed critically the limits and advantages of these techniques and been able to measure some elastoplastic parameters of both phases. Specifically, we have analyzed by PF-QNM two nanostructured bainitic steels, with a finer and a coarser structure, and found that both phases have a similar Young's modulus.

  14. Temperature-dependent mechanical properties of single-layer molybdenum disulphide: Molecular dynamics nanoindentation simulations

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Junhua, E-mail: junhua.zhao@uni-weimar.de [Jiangsu Province Key Laboratory of Advanced Manufacturing Equipment and Technology of Food, Jiangnan University, 214122 Wuxi (China); Institute of Structural Mechanics, Bauhaus-University Weimar, 99423 Weimar (Germany); Jiang, Jin-Wu, E-mail: jwjiang5918@hotmail.com [Institute of Structural Mechanics, Bauhaus-University Weimar, 99423 Weimar (Germany); Rabczuk, Timon, E-mail: timon.rabczuk@uni-weimar.de [Institute of Structural Mechanics, Bauhaus-University Weimar, 99423 Weimar (Germany); School of Civil, Environmental and Architectural Engineering, Korea University, 136-701 Seoul (Korea, Republic of)

    2013-12-02

    The temperature-dependent mechanical properties of single-layer molybdenum disulphide (MoS{sub 2}) are obtained using molecular dynamics (MD) nanoindentation simulations. The Young's moduli, maximum load stress, and maximum loading strain decrease with increasing temperature from 4.2 K to 500 K. The obtained Young's moduli are in good agreement with those using our MD uniaxial tension simulations and the available experimental results. The tendency of maximum loading strain with different temperature is opposite with that of metal materials due to the short range Stillinger-Weber potentials in MoS{sub 2}. Furthermore, the indenter tip radius and fitting strain effect on the mechanical properties are also discussed.

  15. Anomalous Surface Deformation of Sapphire Clarified by 3D-FEM Simulation of the Nanoindentation

    Science.gov (United States)

    Nowak, Roman; Manninen, Timo; Li, Chunliang; Heiskanen, Kari; Hannula, Simo-Pekka; Lindroos, Veikko; Soga, Tetsuo; Yoshida, Fusahito

    This work clarifies the origin of anomalous surface deformation reflected by peculiar surface patterns around indentation impressions on various crystallographic planes of sapphire. The three-dimensional finite element simulation (3D-FEM) of nanoindentation in Al2O3 crystal allowed the authors to localize the regions in which various kinds of twinning and slip are most prone to be activated. The work provides a novel approach to the “hardness anisotropy”, which was modeled so far using a modified uniaxial-stress approximation of this essentially 3D, non-isotropic contact problem. The calculated results enabled the authors to unravel the asymmetric surface deformation detected on prismatic planes by the high-resolution microscopy, which cannot be explained using simple crystallographic considerations.

  16. Molecular dynamics simulation of nano-indentation of (111) cubic boron nitride with optimized Tersoff potential

    Science.gov (United States)

    Zhao, Yinbo; Peng, Xianghe; Fu, Tao; Huang, Cheng; Feng, Chao; Yin, Deqiang; Wang, Zhongchang

    2016-09-01

    We conduct molecular dynamics simulation of nanoindentation on (111) surface of cubic boron nitride and find that shuffle-set dislocations slip along direction on {111} plane at the initial stage of the indentation. The shuffle-set dislocations are then found to meet together, forming surfaces of a tetrahedron. We also find that the surfaces are stacking-fault zones, which intersect with each other, forming edges of stair-rod dislocations along direction. Moreover, we also calculate the generalized stacking fault (GSF) energies along various gliding directions on several planes and find that the GSF energies of the {111} and {111} systems are relatively smaller, indicating that dislocations slip more easily along and directions on the {111} plane.

  17. Effect of pores on the micromechanics of plasma-sprayed Cr3C2-NiCr coating in the nanoindentation testing

    Science.gov (United States)

    Zhang, Yongang; Wang, Yinzhen; Feng, Tao; Sun, Yongxing; Dong, Junzhe; Gao, Wei

    2017-07-01

    The elastoplastic properties of plasma-sprayed Cr3C2-NiCr coatings were obtained through the dimension analysis and inverse analysis by combining the experimental nanoindentation tests and numerical modeling. The digital image processing technique was used to extract the pore distribution inside the coatings based on the actual microstructure. Finally, the effect of pore distribution on the coating residual stress during nanoindentation process was analyzed through simulations. The anisotropic pore microstructure shows different mechanical responses and stress propagation behaviors during nanoindentation process. The elastic modulus of the coating demonstrates anisotropy along the spraying direction and the transverse directions due to the presence of pores.

  18. Factors impacting nanoindentation testing results of the cuticle of dung beetle Copris ochus Motschulsky

    Institute of Scientific and Technical Information of China (English)

    TONG Jin; SUN Ji-yu; CHEN Dong-hui; ZHANG Shu-jun

    2004-01-01

    The cuticle of dung beetle is a layered composite material in micro- or nano-scale. Dung beetle can fly, walk and dig. It can shovel and compact dung of mammals into balls. It use foreleg to walk, midleg and hindleg to hold and impel dung ball.Its two foreleges as digging legs are developed. The factors impacting the nanoindentation testing results of the femur cuticle of forelegs of dung beetle Copris ochus Motschulsky were examined. The nanomechanical test instrument used for the tests was Hysitron nanomechanical system. The results shown that the holding time and loading time are important factors impacting the accuracy of such indentation properties as reduced modulus (Er) and the harness ( H ) of the femur cuticle of the forelegs of dung beetle Copris ochus Motschulsky in nanoscale. There exists a threshold holding time of 20 s for the reduced modulus of the femur cuticle. The tests of nanoindentation creep property and the regression analysis of relationship between the depth increment at the maximum load and the time further confirmed the correction of the above threshold holding time.There exist visco-elastic-plastic behaviour and creep phenomenon in the femur cuticle during indenting. Its creep property during the holding procedure at maximum load can be regressed by a general logarithmic equation. The equation fitted by the testing data is △h = 54.834 52 ln(0.007 23t +1.004 86), where, △h is the depth increment at the maximum load and t is the time.

  19. Nanoindentation deformation of a bi-phase AlCrCuFeNi{sub 2} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yuan [School of Mechanical Engineering, Shanghai Dianji University, 200245 Shanghai (China); Zhao, Guangfeng [Materials Program, Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506 (United States); Wen, Xiyu [Center for Aluminum Technology, University of Kentucky, Lexington, KY 40511 (United States); Qiao, Junwei [Taiyuan University of Technology, Taiyuan, 030024 (China); Yang, Fuqian, E-mail: fyang0@engr.uky.edu [Materials Program, Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506 (United States)

    2014-09-01

    Highlights: • The AlCrCuFeNi{sub 2} HEA consisted of BCC solid solution and FCC solid solution. • The indentation hardness of the BCC crystals is larger than the FCC crystals. • The contact modulus of the FCC crystals is larger than the BCC crystals. - Abstract: High-entropy alloys (HEA) are multicomponent alloys with lattice structures, which have unique mechanical properties. Using X-ray diffraction, the structure of as cast AlCrCuFeNi{sub 2} HEA was characterized. The AlCrCuFeNi{sub 2} HEA consisted of body centered-cubic (BCC) solid solution and face centered-cubic (FCC) solid solution. Nanoindentation was used to characterize the indentation deformation of the FCC and BCC crystals in the AlCrCuFeNi{sub 2} HEA. Both the indentation hardness and the contact modulus of the FCC and BCC crystals decreased slightly with the increase in the indentation load and became constant for large indentation loads. For the indentation load larger than 500 μN, the contact modulus and the indentation hardness of the BCC crystals are 146 and 4.6 GPa, respectively, and the contact modulus and the indentation hardness of the FCC crystals are 207 and 2.8 GPa, respectively. The plastic energy dissipated in the nanoindentation increased with the indentation load and was proportional to the 1.77 and 1.88 power of the indentation load for the FCC and BCC crystals, respectively. The ratio of the dissipated plastic energy to the total energy in the indentations was a linear function of the ratio of the residual indentation depth to the corresponding maximum indentation depth. The slope of the energy ratio verse the indentation depth ratio for the BCC crystals is larger than that for the FCC crystals.

  20. Microtiter plate-sized standalone chip holder for microenvironmental physiological control in gas-impermeable microfluidic devices

    NARCIS (Netherlands)

    Harink, Björn; le Gac, Severine; Baiao Barata, David; van Blitterswijk, Clemens; Habibovic, Pamela

    2014-01-01

    We present a microtiter plate-sized standalone chip holder for precise control of physiological conditions inside closed microfluidic cell culture systems, made from gas-impermeable materials. Specifically, we demonstrate the suitability of the holder to support cell growth in a glass chip, to allow

  1. 25 CFR 115.502 - Who inherits the money in an IIM account when an account holder dies?

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Who inherits the money in an IIM account when an account holder dies? 115.502 Section 115.502 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR... Who inherits the money in an IIM account when an account holder dies? At the end of all...

  2. 30 CFR 285.107 - How do I show that I am qualified to be a lessee or grant holder?

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false How do I show that I am qualified to be a lessee or grant holder? 285.107 Section 285.107 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT... holder? (a) You must demonstrate your technical and financial capability to construct, operate,...

  3. Measured thermal and fast neutron fluence rates for ATF-1 holders during ATR cycle 160A

    Energy Technology Data Exchange (ETDEWEB)

    Walker, B. J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Miller, D. T. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-06-06

    This report contains the thermal (2200 m/s) and fast (E>1MeV) neutron fluence rate data for the ATF-1 holders located in core for ATR Cycle 160A which were measured by the Radiation Measurements Laboratory (RML).

  4. Surgical robotics. Evaluation of the Computer Motion AESOP 3000 robotic endoscope holder.

    Science.gov (United States)

    2002-07-01

    The use of robots to manipulate surgical instruments inside the patient has already moved from the world of fiction to fact. While the widespread use of full-function surgical robots is still many years away, less sophisticated robots that perform very specific surgical functions are already at a stage where the typical hospital can consider their use. Currently, the most affordable and commonly used type of "surgical-assist" robot is the robotic endoscope holder, which is used to hold and position rigid endoscopes during minimally invasive surgery. In this study, we introduce readers to the topic of surgical robotics, focusing specifically on robotic endoscope holders. The study includes a Technology Management Guide, in which we discuss who should and who shouldn't consider implementing such robots, and it includes our evaluation protocol and findings for one such robot, the Computer Motion AESOP 3000. We judged the evaluated system based on its performance relative to the human scope holders it is designed to replace, as well as its safety and ease of use. While we found the AESOP 3000 to be an acceptable, and sometimes preferred, alternative to the use of a human scope holder, we caution that many healthcare facilities won't see sufficient clinical benefit to warrant its purchase at this time.

  5. A holder assembly for cooperating with an environmental cell and an electron microscope

    NARCIS (Netherlands)

    Zandbergen, H.W.; Pleun, D.; Van Veen, G.N.A.

    2013-01-01

    The invention relates to a holder assembly for cooperating with an environmental cell ( 101 ) and an electron microscope, the environmental cell showing a fluid inlet (103), the electron microscope showing a vacuum wall (110) for separating an evacuable part of the electron microscope from the

  6. Analytical and Experimental Studies on Critical Blank-holder Forces in Cylindrical cup deep drawing

    Institute of Scientific and Technical Information of China (English)

    Lin Zhongqin; Sun Chengzhi; Chen Guanlong; Yu Haiyan

    2004-01-01

    Based on the plastic deformation theory and energy method, the critical blank-holder forces (BHF) of wrinkling and fracture in the cylindrical cup deep-drawing are analyzed. The verify experiments were performed and compared with the theory analysis results. The predictions agree well with the experiment results. Thus, the validated presenttheoretical analysis model may be applied to determinate the suitable BHF.

  7. DETERMINATION OF BLANK HOLDER FORCE IN SHEET METAL DEEP DRAWING PROCESS

    Institute of Scientific and Technical Information of China (English)

    Y.J.Luo; Y.Q.Zhang; 等

    2003-01-01

    Blank holder force(BHF) is an important measure to control the sheet metal forming.BHF is identified quickly using artificial network(ANN) on the basis of its analytical description.And critical rupture and wrinkle BHF curves are given.A close-loop control system is established to finish the forming process.

  8. 75 FR 68224 - Safety Management Systems for Part 121 Certificate Holders

    Science.gov (United States)

    2010-11-05

    ... Federal Aviation Administration 14 CFR Parts 5 and 119 RIN 2120-AJ86 Safety Management Systems for Part... certificate holder operating under 14 CFR part 121 to develop and implement a safety management system (SMS) to improve the safety of their aviation related activities. A safety management system is...

  9. 19 CFR 134.24 - Containers or holders not designed for or capable of reuse.

    Science.gov (United States)

    2010-04-01

    ... consumed. (b) Imported empty. Disposable containers or holders imported for distribution or sale are... goods of a NAFTA country are imported by persons or firms who fill or package them with various products.... However, if the container is normally opened by the ultimate purchaser prior to purchase, only the...

  10. Assessing the authority of political office-holders : The leadership capital index

    NARCIS (Netherlands)

    Bennister, Mark; t Hart, Paul; Worthy, Benjamin

    2015-01-01

    This article argues that the extent to which political office-holders can effectively attain and wield authority is a function of the stock of ‘leadership capital’. Drawing on the concept of political capital, the article defines leadership capital as aggregate authority composed of three dimensions

  11. Correlation between porosity and space holder content at different sintering temperatures of aluminum foam

    Science.gov (United States)

    Rushdi, N. M. F. M.; Jamaludin, S. B.; Mazlee, M. N.; Jamal, Z. A. Z.

    2016-07-01

    Aluminum foam is the most popular metal foam that can be used as energy absorbers, heat exchangers, air-oil separators and structure core of fuel cells. Melt-foaming agent, melt-gas injection, investment casting and powder-foaming agent techniques can be used to manufacture aluminum foam, but these techniques are too expensive. In this study, the aluminum foam was manufactured via a sintering dissolution process (SDP). Powders of aluminum and sodium chloride as space holder (25, 40, 50 wt. %) were mixed together to produce a homogeneous mixture. The mixture was compacted at 200 MPa followed by sintering at 500, 550 and 600˚C for 2 hours. A warm running water stream was used to dissolve the space holder that was embedded in the aluminum. The result showed that, the space holder content performed a significant role to control the total porosity to a value between 18 and 40%, and the porosity increased with increasing content of space holder and sintering temperature.

  12. A holder assembly for cooperating with an environmental cell and an electron microscope

    NARCIS (Netherlands)

    Zandbergen, H.W.; Pleun, D.; Van Veen, G.N.A.

    2013-01-01

    The invention relates to a holder assembly for cooperating with an environmental cell ( 101 ) and an electron microscope, the environmental cell showing a fluid inlet (103), the electron microscope showing a vacuum wall (110) for separating an evacuable part of the electron microscope from the outsi

  13. DETERMINATION OF BLANK HOLDER FORCE IN SHEET METAL DEEP DRAWING PROCESS

    Institute of Scientific and Technical Information of China (English)

    Y.J. Luo; Y.Q. Zhang; D.N. He

    2003-01-01

    Blank holder force (BHF) is an important measure to control the sheet metal forming.BHF is identified quickly using artificial neural network (ANN) on the basis of itsanalytical description. And critical rupture and wrinkle BHF curves are given. Aclose-loop control system is established to finish the forming process.

  14. Holder regularity for signed solutions to singular porous medium type equations

    Directory of Open Access Journals (Sweden)

    Simona Puglisi

    2012-11-01

    Full Text Available We prove Holder regularity for bounded signed solution to singular porous medium type equations, whose prototype is $$ u_t-hbox{div}m|u|^{m-1}Du=0quadhbox{weakly in }E_T, $$ with $min(0,1$.

  15. 76 FR 24504 - Agency Information Collection Activities: BioWatch Filter Holder Log

    Science.gov (United States)

    2011-05-02

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY Agency Information Collection Activities: BioWatch Filter Holder Log AGENCY: Department of... submissions of responses. Analysis Agency: Department of Homeland Security, DHS. Title: BioWatch Filter...

  16. "Shelby County v. Holder": What It Means for the Voting Rights Act

    Science.gov (United States)

    Schwinn, Steven D.

    2013-01-01

    This summer, the U.S. Supreme Court ruled in "Shelby County v. Holder" that Congress had exceeded its Fifteenth Amendment enforcement authority when it reauthorized a part of the Voting Rights Act (a coverage formula) that forced places with a history of discrimination to get federal approval before making changes to their election laws.…

  17. Influence of endodontic instrument-holder on sterilization efficacy. A pilot in-vitro study.

    Directory of Open Access Journals (Sweden)

    Angelo Carrizo

    2013-08-01

    Full Text Available Infection control is crucial in dentistry and various methods have been designed to assure its efficacy. However, little information exists regarding the influence it could have the instrument-holder of endodontic files. The aim of this research was to determine the influence of three instruments-holders on sterilization efficacy of endodontic files. Methods: A pilot in-vitro study. 60 endodontic files were contaminated by biomechanical preparation of extracted molars with periapical abscess, then processed according to the standard washing method. The endodontic files were divided into 3 groups (n=20 and assigned to 3 instrument-holders: Metallic box (MB, surgical gauze (SG and synthetic sponge (SS. Then, the files were packaged and sterilized by autoclaving (134°C/45min. Microbiological culture was performed in thioglycolate solution for each endodontic file (37ºC/5days. Results: The overall sterilization efficacy was 91.7%, 80% for MB, 100% for SS, and 95% for SG, with no statistically significant differences (p=0.06 between the groups. Conclusions: The lack of differences in the efficacy of sterilization may be due to the reduced sample; therefore, a full-size study is necessary to confirm this outcomes. The results of this study discourage the use of the MB as instrument-holder until a full-size study can confirm this data.

  18. 19 CFR 134.22 - General rules for marking of containers or holders.

    Science.gov (United States)

    2010-04-01

    ... SECURITY; DEPARTMENT OF THE TREASURY COUNTRY OF ORIGIN MARKING Marking of Containers or Holders § 134.22... origin of the article whether or not the article is marked to indicate its country of origin. (b....S.C. 1202), shall be marked to indicate clearly the country of their own origin in addition to...

  19. Evaluation of a cigarette holder for use in analytical smoking machines

    NARCIS (Netherlands)

    Hissink, M.; Bosman, R.

    1987-01-01

    A cigarette holder that simulates the lips of a human smoker has been tested for use in measurements of yields of tar, nicotine, and carbon monoxide. In this study, we tested five different brands of cigarettes that ranged in tar yield from 1 to 15 mg per cigarette. The dependence of the yields and

  20. H(o)lder Continuity of Weak Solutions for Parabolic Equations with Nonstandard Growth Conditions

    Institute of Scientific and Technical Information of China (English)

    Meng XU; Ya Zhe CHEN

    2006-01-01

    In this paper, we investigate the interior regularity including the local boundedness and the interior H(o)lder continuity of weak solutions for parabolic equations of the p(x,t)-Laplacian type. We improve the Moser iteration technique and generalize the known results for the elliptic problem to the corresponding parabolic problem.

  1. Holder and Topic Based Analysis of Emotions on Blog Texts: A Case Study for Bengali

    Science.gov (United States)

    Das, Dipankar; Bandyopadhyay, Sivaji

    The paper presents an extended approach of analyzing emotions of the blog users on different topics. The rule based techniques to identify emotion holders and topics with respect to their corresponding emotional expressions helps to develop the baseline system. On the other hand, the Support Vector Machine (SVM) based supervised framework identifies the holders, topics and emotional expressions from the blog sentences by outperforming the baseline system. The existence of many to many relations between the holders and the topics with respect to Ekman's six different emotion classes has been examined using two way evaluation techniques, one is with respect to holder and other is from the perspective of topic. The results of the system were found satisfactory in comparison with the agreement of the subjective annotation. The error analysis shows that the topic of a blog at document level is not always conveyed at the sentence level. Moreover, the difficulty in identifying topic from a blog document is due to the problem of identifying some features like bigrams, Named Entities and sentiment. Thus, we employed a semantic clustering approach along with these features to identify the similarity between document level topic and sentential topic as well as to improve the results of identifying the document level topic.

  2. 27 CFR 70.145 - Purchasers, holders of security interests, mechanic's lienors, and judgment lien creditors.

    Science.gov (United States)

    2010-04-01

    ... security interests, mechanic's lienors, and judgment lien creditors. 70.145 Section 70.145 Alcohol, Tobacco... Lien for Taxes § 70.145 Purchasers, holders of security interests, mechanic's lienors, and judgment... in § 70.143(a) of this part), mechanic's lienor (as defined in § 70.143(b) of this part), or...

  3. Measurements and Counts for Notacanthidae Specimens

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Taxonomic data were collected for specimens of deep-sea spiny eels (Notacanthidae) from the Hawaiian Ridge by Bruce C. Mundy. Specimens were collected off the north...

  4. Evaluation of Different Holder Devices for Freeze-Drying in Dual-Chamber Cartridges With a Focus on Energy Transfer.

    Science.gov (United States)

    Korpus, Christoph; Friess, Wolfgang

    2017-04-01

    For freeze-drying in dual-chamber cartridges, a holder device to enable handling and safe positioning in the freeze-dryer is necessary. The aim of this study was to analyze 4 different types of holder devices and to define the best system based on energy transfer. The main criteria were drying homogeneity, ability to minimize the influence of atypical radiation on product temperatures, and heat transfer effectiveness. The shell holder reduced the influence of atypical radiation by almost 60% compared to a block system and yielded the most homogenous sublimation rates. Besides the most efficient heat transfer with values of 1.58E-4 ± 2.06E-6 cal/(s*cm(2)*K) at 60 mTorr to 3.63E-4 ± 1.85E-5 cal/(s*cm(2)*K) at 200 mTorr for Ktot, reaction times to shelf temperature changes were up to 4 times shorter compared to the other holder systems and even faster than for vials. The flexible holder provided a comparable shielding against atypical radiation as the shell but introduced a third barrier against energy transfer. Block and guardrail holder were the least efficient system tested. Hence, the shell holder provided the best radiation shielding, enhanced the transferability of the results to a larger scale, and improved the homogeneity between the dual-chamber cartridges.

  5. Numerical model of the nanoindentation test based on the digital material representation of the Ti/TiN multilayers

    Directory of Open Access Journals (Sweden)

    Perzyński Konrad

    2015-06-01

    Full Text Available The developed numerical model of a local nanoindentation test, based on the digital material representation (DMR concept, has been presented within the paper. First, an efficient algorithm describing the pulsed laser deposition (PLD process was proposed to realistically recreate the specific morphology of a nanolayered material in an explicit manner. The nanolayered Ti/TiN composite was selected for the investigation. Details of the developed cellular automata model of the PLD process were presented and discussed. Then, the Ti/TiN DMR was incorporated into the finite element software and numerical model of the nanoindentation test was established. Finally, examples of obtained results presenting capabilities of the proposed approach were highlighted.

  6. Effect of Strain Rate on Deformation Behavior of AlCoCrFeNi High-Entropy Alloy by Nanoindentation

    Science.gov (United States)

    Tian, L.; Jiao, Z. M.; Yuan, G. Z.; Ma, S. G.; Wang, Z. H.; Yang, H. J.; Zhang, Y.; Qiao, J. W.

    2016-06-01

    In this study, nanoindentation tests with continuous stiffness measurement technique were measured to investigate the deformation behavior of a high-entropy alloy AlCoCrFeNi under different indentation strain rates at room temperature. Results suggest that the creep behavior exhibits remarkable strain rate dependence. In-situ scanning images showed a conspicuous pileup around the indents, indicating that an extremely localized plastic deformation occurred during the nanoindentation. Under different strain rates, elastic modulus basically remains unchanged, while the hardness decreases with increasing indentation depth due to the indentation size effect. Furthermore, the modulus and hardness of AlCoCrFeNi HEAs are greater than that of the Al x CoCrFeNi ( x = 0.3,0.5) at the strain rate of 0.2 s-1 due to its higher negative enthalpy of mixing related to the atomic binding force, and the solid solution strengthening induced by the lattice distortion, respectively.

  7. Plasticity and ultra-low stress induced twin boundary migration in nanotwinned Cu by in situ nanoindentation studies

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y.; Chen, Y. [Department of Materials Science and Engineering, Texas A and M University, College Station, Texas 77843 (United States); Jian, J. [Department of Electrical Engineering, Texas A and M University, College Station, Texas 77843 (United States); Wang, H. [Department of Materials Science and Engineering, Texas A and M University, College Station, Texas 77843 (United States); Department of Electrical Engineering, Texas A and M University, College Station, Texas 77843 (United States); Zhang, X., E-mail: zhangx@tamu.edu [Department of Materials Science and Engineering, Texas A and M University, College Station, Texas 77843 (United States); Department of Mechanical Engineering, Texas A and M University, College Station, Texas 77843 (United States)

    2014-06-09

    Nanotwinned metals have rare combinations of mechanical strength and ductility. Previous studies have shown that detwinning occurs in plastically deformed nanotwinned metals. Although molecular dynamics simulations have predicted that fine nanotwins can migrate at low stress, there is little in situ evidence to validate such predictions. Also it is unclear if detwinning occurs prior to or succeeding plastic yielding. Here, by using in situ nanoindentation in a transmission electron microscope, we show that a non-elastic detwinning process in nanotwinned Cu occurred at ultra-low indentation stress (0.1 GPa), well before the stress necessary for plastic yielding. Furthermore, the in situ nanoindentation technique allows us to differentiate dislocation-nucleation dominated microscopic yielding preceding macroscopic yielding manifested by dislocation-transmission through twin boundaries. This study thus provides further insights for understanding plasticity in nanotwinned metals at microscopic levels.

  8. Effects of brushing timing after erosive challenge on enamel loss in situ: White light interferometer and nanoindentation study.

    Science.gov (United States)

    Tsuda, Yuka; Kitasako, Yuichi; Sadr, Alireza; Nakashima, Syozi; Tagami, Junji

    2016-01-01

    This in situ study aimed to evaluate effects of waiting periods after erosive challenge before toothbrushing on enamel abrasion and nanoindentation hardness. Ten subjects wore intraoral appliances each with a set of 4 bovine enamel blocks. The enamel blocks were subjected to 2 cycles a day for 3 days as follows; intraoral exposure to form acquired pellicle and extraoral erosion followed by either 0, 3, 30 or 60 min intraoral exposure and then brushing, which was performed using an automatic brushing machine. Abrasive loss was assessed by white light interferometry. Nanoindentation was performed to calculate relative hardness. Abrasion and relative hardness were statistically analyzed by ANOVA. Abrasive loss was significantly less in groups exposed to saliva compared with 0 min (p0.05). Relative hardness was statistically higher after intraoral exposure, but no differences existed among any intraoral exposure periods (p>0.05).

  9. Clinicopathological study of hysterectomised specimens

    Directory of Open Access Journals (Sweden)

    Saravana A.

    2016-12-01

    Full Text Available Background: Hysterectomy is the commonest major surgical procedure performed in gynecology. It can be done by abdominal or vaginal route and with the help of laparoscopy. Hysterectomy is an effective treatment option for many conditions like fibroid, abnormal uterine bleeding, endometriosis, adenomyosis, uterine prolapse, pelvic inflammatory disease and cancer of reproductive organ when other treatment options are contraindicated or have failed, or if the woman no longer wishes to retain her menstrual and reproductive. The aim and objective of the study was to correlate indications of hysterectomy with histopathological findings in hysterectomised patients. Methods: A retrospective study was carried on 113 hysterectomised cases over a period of one year from June 2015 to May 2016. The data regarding the patient’s age, parity, clinical diagnosis, type of hysterectomy and histopathological diagnosis were reviewed by the records and analyzed. Results: A total of 113 cases of hysterectomies were studied. Hysterectomies were distributed over a wide age ranging from 20 years to 75 years. Most common age group was 41-50 years. Among hystectomies majority were done through vaginal route 86 (76.1% and 26 (23% cases were done through abdominal route. Most common clinical diagnosis was fibroid uterus in 44(38.9% cases. Most of the hysterectomies were done for benign conditions. In final histopathological report most common diagnosis was fibroid uterus in 45(39.8% hysterectomy specimens. It was correlated well with clinical diagnosis. Next most common histopathological diagnosis was Adenomyosis. Conclusions: Histopathological analysis correlated well with preoperative clinical diagnosis in majority of cases. The commonest indication and histopathological finding in our study was fibroid uterus. Next most common histopathological finding was Adenomyosis. Most commonly hysterectomies were done through vaginal route in our study.

  10. [The German Environmental Specimen Bank].

    Science.gov (United States)

    Schröter-Kermani, Christa; Gies, Andreas; Kolossa-Gehring, Marike

    2016-03-01

    The main objective of the German Environmental Specimen Bank (ESB) is the long-term storage of environmental and human samples under stable deep-freeze conditions for future research. The ESB is unique in providing a continuous historical record of environmental and human exposure to chemicals in Germany. ESB was started parallel to the development of the first German Chemicals Legislation in the late 1970s. In 1979, the ESB test operation began. After the Chemicals Law came into force in 1982, the ESB was established as a permanent facility in 1985. With the new European Chemicals Legislation, REACH, in 2007 responsibility for the safety of commercial chemicals and risk assessment was assigned to the industry. Since then, the ESB has become even more important in verifying the self-assessment of the industry, in evaluating the effectiveness of regulations, thus ensuring the protection of humans and the environment against adverse effects caused by exposure to chemicals. These objectives are pursued by the regular monitoring of contaminations and the assessment of temporal trends. Demonstrating the necessity of deriving exposure reduction measures, ESB results serve as key information for policy-makers. Information on preventing exposure to chemicals is available to the general public and to the public health services. The ESB is thus an important monitoring instrument of the Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety. The Federal Environment Agency operates the ESB based on its own concepts, heads the scientific data evaluation and transfers results into the environmental policy arena and to the general public.

  11. Grain Growth Orientation and Anisotropy in Cu6Sn5 Intermetallic: Nanoindentation and Electron Backscatter Diffraction Analysis

    Science.gov (United States)

    Choudhury, Soud Farhan; Ladani, Leila

    2014-04-01

    As the size of joints in micro/nano-electronics diminishes, the role of intermetallic (IMC) layers becomes more significant. It was shown that solder joint strength is controlled largely by IMC strength at higher strain rates. Additionally, there is a possibility that very small joints are completely composed of IMCs. Further miniaturization of joints may result in statistical grain size effects. Therefore, it is essential to characterize IMC materials and understand their anisotropic mechanical properties. One of the most common types of IMCs in microelectronic joints is Cu6Sn5, which is formed in a variety of bonding materials with different compositions of Sn, Cu, and Ag. This work studies through nanoindentation elastic-plastic properties of a single grain of Cu6Sn5 IMC in a Sn-3.5Ag/Cu system with reflow soldering. Elastic properties such as elastic modulus and hardness were determined from the nanoindentation load-depth curve. The reverse analysis model described by Dao et al. was used to extract plastic properties such as yield strength and strain hardening exponent from nanoindentation data. Care was taken to achieve indentation of single grains with sufficient accuracy and repeatability. Electron backscatter diffraction (EBSD) mapping was used to determine orientation of Cu6Sn5 grains and to relate the orientation with the load-depth curve results of nanoindentation and the corresponding elastic and plastic properties. The EBSD results indicated that the Cu6Sn5 crystal structure is hexagonal. Columnar growth of the Cu6Sn5 grains was observed as the grains mostly grew along the c-axis of the crystal. Indentation of different grains parallel to the basal plane showed no significant difference in mechanical properties.

  12. Young’s Modulus of Polycrystalline Titania Microspheres Determined by In Situ Nanoindentation and Finite Element Modeling

    Directory of Open Access Journals (Sweden)

    Peida Hao

    2014-01-01

    Full Text Available In situ nanoindentation was employed to probe the mechanical properties of individual polycrystalline titania (TiO2 microspheres. The force-displacement curves captured by a hybrid scanning electron microscope/scanning probe microscope (SEM/SPM system were analyzed based on Hertz’s theory of contact mechanics. However, the deformation mechanisms of the nano/microspheres in the nanoindentation tests are not very clear. Finite element simulation was employed to investigate the deformation of spheres at the nanoscale under the pressure of an AFM tip. Then a revised method for the calculation of Young’s modulus of the microspheres was presented based on the deformation mechanisms of the spheres and Hertz’s theory. Meanwhile, a new force-displacement curve was reproduced by finite element simulation with the new calculation, and it was compared with the curve obtained by the nanoindentation experiment. The results of the comparison show that utilization of this revised model produces more accurate results. The calculated results showed that Young’s modulus of a polycrystalline TiO2 microsphere was approximately 30% larger than that of the bulk counterpart.

  13. Simulation of nanoindentation experiment on RF magnetron sputtered nanocolumnar V2O5 film using finite element method

    Science.gov (United States)

    Porwal, Deeksha; Gupta, A. K.; Pillai, Anju M.; Sharma, Anand Kumar; Mukhopadhyay, Anoop Kumar; Khan, Kallol; Dey, Arjun

    2016-07-01

    The present work reports the nanomechanical behavior of a pulsed radio frequency (RF) magnetron sputtered vanadium pentoxide (V2O5) film deposited on silicon (Si) substrate using a combination of nanoindentation experiments and a finite element model (FEM). Deposited V2O5 film is characterized by x-ray diffraction (XRD), nanoprofilometry, field emission scanning electron microscopy (FESEM), nanoindentation and FEM. The phase pure 6.16 μm V2O5 film shows a nanocolumnar structure. The film exhibits nanohardness (H) of 0.16 ± 0.013 GPa and Young’s modulus (E) of about 12.05 ± 1.41 GPa. The FEM reproduces experimentally obtained load versus depth (P-h) plot and subsequently give yield stress and strain hardening component data of V2O5 film on Si substrate. Stress-strain behavior and von-Mises stress distribution of the V2O5 film with Si substrate system are also simulated. The FE model confirms the local maximum equivalent stress active underneath the nanoindenters to be nearly twice as high as the yield stress and thereby explains the plastic deformation observed in the V2O5 film.

  14. The Effect of Butternut Squash (Cucurbita moschata) on the Incomes of the Small-Holders in Suba District, Kenya

    OpenAIRE

    H. N. Isaboke; P. Mshenga; M. Saidi

    2012-01-01

    Butternut squash is an emerging economic crop in Kenya with ready market and high nutritional value. It was introduced to promote food security and enhance the incomes of the small-holder farmers in Suba district. However it is not clear whether butternut could address the problem of low income among small-holder farmers. The aim of the study was to investigate the effect of butternut squash on the incomes of the small-holders. The choice of the study area was due to persistence of poverty pr...

  15. Design and preliminary in vivo validation of a robotic laparoscope holder for minimally invasive surgery.

    Science.gov (United States)

    Herman, Benoît; Dehez, Bruno; Duy, Khanh Tran; Raucent, Benoît; Dombre, Etienne; Krut, Sébastien

    2009-09-01

    Manual manipulation of the camera is a major source of difficulties encountered by surgeons while performing minimally invasive laparoscopic surgery. A survey of laparoscopic procedures and a review of existing active and passive holders were conducted. Based on these analyses, essential requirements were highlighted for such devices. Pursuant to this, a novel active laparoscope manipulator was designed, paying particular attention to ergonomics and ease of use. Several trials on the pelvitrainer and a first in vivo procedure were performed to validate the original design of our device. Phantom experiments demonstrated ease of use of the robot and advantages of the intuitive joystick with omnidirectional displacements and speed control. The compactness of the device and image stability were appreciated during the surgical trial. A novel robotic laparoscope holder has been developed and produced. An in vivo trial proved its value in clinical practice, enabling surgeons to work more comfortably.

  16. H\\"older Estimates for Singular Non-local Parabolic Equations

    CERN Document Server

    Kim, Sunghoon

    2011-01-01

    In this paper, we establish local H\\"older estimate for non-negative solutions of the singular equation \\eqref{eq-nlocal-PME-1} below, for $m$ in the range of exponents $(\\frac{n-2\\sigma}{n+2\\sigma},1)$. Since we have trouble in finding the local energy inequality of $v$ directly. we use the fact that the operator $(-\\La)^{\\sigma}$ can be thought as the normal derivative of some extension $v^{\\ast}$ of $v$ to the upper half space, \\cite{CS}, i.e., $v$ is regarded as boundary value of $v^{\\ast}$ the solution of some local extension problem. Therefore, the local H\\"older estimate of $v$ can be obtained by the same regularity of $v^{\\ast}$. In addition, it enables us to describe the behaviour of solution of non-local fast diffusion equation near their extinction time.

  17. A Machine Learning Approach for Opinion Holder Extraction in Arabic Language

    Directory of Open Access Journals (Sweden)

    Mohamed Elarnaoty

    2012-03-01

    Full Text Available Opinion mining aims at extracting useful subjective information from reliable amounts of text. Opinion mining holder recognition is a task that has not been considered yet in Arabic Language. This task essentially requires deep understanding of clauses structures. Unfortunately, the lack of a robust, publicly available, Arabic parser further complicates the research. This paper presents a leading research for the opinion holder extraction in Arabic news independent from any lexical parsers. We investigate constructing a comprehensive feature set to compensate the lack of parsing structural outcomes. The proposed feature set is tuned from English previous works coupled with our proposed semantic field and named entities features. Our feature analysis is based on Conditional Random Fields (CRF and semi-supervised pattern recognition techniques. Different research models are evaluated via cross-validation experiments achieving 54.03 F-measure. We publicly release our own research outcome corpus and lexicon for opinion mining community to encourage further research.

  18. A Machine Learning Approach for Opinion Holder Extraction in Arabic Language

    Directory of Open Access Journals (Sweden)

    Mohamed Elarnaoty

    2012-04-01

    Full Text Available Opinion mining aims at extracting useful subjective information from reliable amounts of text. Opinionmining holder recognition is a task that has not been considered yet in Arabic Language. This task essentially requires deep understanding of clauses structures. Unfortunately, the lack of a robust, publicly available, Arabic parser further complicates the research. This paper presents a leading research for the opinion holder extraction in Arabic news independent from any lexical parsers. We investigate constructing a comprehensive feature set to compensate the lack of parsing structural outcomes. The proposed feature set is tuned from English previous works coupled with our proposed semantic field and named entities features. Our feature analysis is based on Conditional Random Fields (CRF and semi-supervised patternrecognition techniques. Different research models are evaluated via cross-validation experiments achieving 54.03 F-measure. We publicly release our own research outcome corpus and lexicon for opinion mining community to encourage further research.

  19. First Clinical Experience in Urologic Surgery with a Novel Robotic Lightweight Laparoscope Holder

    CERN Document Server

    Long, Jean-Alexandre; Lanchon, Cecilia; Voros, Sandrine; Medici, Maud; Descotes, Jean-Luc; Troccaz, Jocelyne; Cinquin, Philippe; Rambeaud, Jean-Jacques; Moreau-Gaudry, Alexandre

    2012-01-01

    Purpose: To report the feasibility and the safety of a surgeon-controlled robotic endoscope holder in laparoscopic surgery. Materials and methods: From March 2010 to September 2010, 20 patients were enrolled prospectively to undergo a laparoscopic surgery using an innovative robotic endoscope holder. Two surgeons performed 6 adrenalectomies, 4 sacrocolpopexies, 5 pyeloplasties, 4 radical prostatectomies and 1 radical nephrectomy. Demographic data, overall set-up time, operative time, number of assistants needed were reviewed. Surgeon's satisfaction regarding the ergonomics was assessed using a ten point scale. Postoperative clinical outcomes were reviewed at day 1 and 1 month postoperatively. Results: The per-protocol analysis was performed on 17 patients for whom the robot was effectively used for surgery. Median age was 63 years, 10 patients were female (59%). Median BMI was 26.8. Surgical procedures were completed with the robot in 12 cases (71 %). Median number of surgical assistant was 0. Overall set-up ...

  20. Holder Continuity for Degenerate Elliptic Variational Equations and Inequalities in Mathematical Finance

    CERN Document Server

    Feehan, Paul M N

    2011-01-01

    The Heston stochastic volatility process, which is widely used as an asset price model in mathematical finance, is a paradigm for a degenerate diffusion process where the degeneracy in the diffusion coefficient is proportional to the square root of the distance to the boundary of the half-plane. The generator of this process with killing, called the elliptic Heston operator, is a second-order degenerate elliptic partial differential operator whose coefficients have linear growth in the spatial variables and where the degeneracy in the operator symbol is proportional to the distance to the boundary of the half-plane. With the aid of weighted Sobolev spaces, we prove supremum bounds, a Harnack inequality, and Holder continuity near the boundary for solutions to elliptic variational equations defined by the Heston partial differential operator, as well as Holder continuity up to the boundary for solutions to elliptic variational inequalities defined by the Heston operator. In mathematical finance, solutions to o...

  1. Nondestructive DNA extraction from museum specimens.

    Science.gov (United States)

    Hofreiter, Michael

    2012-01-01

    Natural history museums around the world hold millions of animal and plant specimens that are potentially amenable to genetic analyses. With more and more populations and species becoming extinct, the importance of these specimens for phylogenetic and phylogeographic analyses is rapidly increasing. However, as most DNA extraction methods damage the specimens, nondestructive extraction methods are useful to balance the demands of molecular biologists, morphologists, and museum curators. Here, I describe a method for nondestructive DNA extraction from bony specimens (i.e., bones and teeth). In this method, the specimens are soaked in extraction buffer, and DNA is then purified from the soaking solution using adsorption to silica. The method reliably yields mitochondrial and often also nuclear DNA. The method has been adapted to DNA extraction from other types of specimens such as arthropods.

  2. H\\"{o}lder continuous retractions and amenable semigroups of uniformly Lipschitzian mappings in Hilbert spaces

    CERN Document Server

    Wiśnicki, Andrzej

    2012-01-01

    Suppose that S is a left amenable semitopological semigroup. We prove that if $\\{T_{t}: t \\in S \\}$ is a uniformly k-Lipschitzian semigroup on a bounded closed and convex subset C of a Hilbert space and $k<\\sqrt{2}$, then the set of fixed points of this semigroup is a H\\"{o}lder continuous retract of C. This gives a qualitative complement to the Ishihara-Takahashi fixed point existence theorem.

  3. K-Dimension and H(o)lder Exponent for Bush Type Fractal Functions

    Institute of Scientific and Technical Information of China (English)

    Wang Hongyong

    2006-01-01

    Bush type fractal functions were defined by means of the expression of Cantor series of real numbers. The upper and lower bound estimates for the K-dimension of such functions were given. In a typical case, the fractal dimensional relations in which the K-dimension equals the box dimension and packing dimension were presented; moreover, the exact H(o)lder exponent were obtained for such Bush type functions.

  4. Making Durable Specimens For Electron Microscopy

    Science.gov (United States)

    Doychak, Joseph

    1989-01-01

    Consistent metal-oxide cross sections prepared quickly. New process makes TEM/STEM cross sections of metal/oxide interfaces. After specimen bars oxidized, placed in specially designed mold. Following encapsulation in zinc alloy, 3-mm-diameter specimen bar sliced into disks suitable for further preparation steps. Technique used to prepare 3-mm-diameter specimens of cross sections of oxides of alloys intended for use at temperatures greater than approximately 600 degree C.

  5. RSB: Research Specimen Banking across the Institution

    OpenAIRE

    Pense, Rick; Grose, Tim; Anderson, Lynn; Lee, H

    2001-01-01

    Research Specimen Banking (RSB) system is a component of the translational investigations infrastructure at Moffitt Cancer Center & Research Institute. It was implemented to provide specimen management functions to support basic science cancer research taking place in conjunction with caner clinical trials. RSB handles the receipt and distribution of clinical specimens to the research labs, with identifiers that both mask personal identity and enable linkage of clinical data to correlative re...

  6. Common criteria among States for storage and use of dried blood spot specimens after newborn screening

    Directory of Open Access Journals (Sweden)

    Carlo Petrini

    2012-06-01

    Full Text Available Biological samples collected in biobanks are a resource with significant research potential. The Italian Joint Group cNB - cNBBSV (National committee of Bioethics - National committee for Biosecurity, Biotechnologies and Life Sciences published a document reporting recommendations on storage and use of dried blood spot (DBS and on the development of a National Network of Regional Newborn Screening Repositories for collection of residual DBS. Several ethical questions (about consent, possible use of genetic information, unanticipated possible usages for research purposes rise from residual newborn screening specimens collections. Moreover, legal and ethical controversies are accentuated by the conflicts between the interests of sample donors, biobank holders, researchers and the public. To overcome these difficulties the identification of a few criteria for storage and research usage of DBS is crucial.

  7. Development and testing of an integrated rotating dynamometer on tool holder for milling process

    Science.gov (United States)

    Rizal, Muhammad; Ghani, Jaharah A.; Nuawi, Mohd Zaki; Che Haron, Che Hassan

    2015-02-01

    The cutting force provides significant information to help understand the machining process, optimization, tool condition monitoring, tool design and others. Hence, various methods of measuring the cutting force have been proposed by many researchers. In this work, an innovative integrated rotating dynamometer and tool holder is designed, constructed and tested that can fulfil the requirement to measure the cutting force in a wireless environment system. The device consists of a strain gauge based sensor that is mounted on a newly designed force sensing element which is then placed in the rotating tool holder. The force sensing element is designed in the form of a symmetrical cross beam type with four arms, shaped as a rectangular parallelepiped. This device is intended to be used in a rotating spindle such as in milling and drilling processes. A conditioning system and an inductive telemetry transmitter unit are incorporated into a modified tool holder in order to collect and transmit the cutting force signal to the data acquisition system. The rotating dynamometer has been subjected to a series of tests to determine its static and dynamic characteristics. Thus, it is tested experimentally by conducting cutting tests up to cutting speed 550 m/min with a single-tool insert. The results show it is suitable and reliable to measure the cutting force in milling processes.

  8. Fabrication of Metallic Biomedical Scaffolds with the Space Holder Method: A Review

    Directory of Open Access Journals (Sweden)

    Budi Arifvianto

    2014-05-01

    Full Text Available Bone tissue engineering has been increasingly studied as an alternative approach to bone defect reconstruction. In this approach, new bone cells are stimulated to grow and heal the defect with the aid of a scaffold that serves as a medium for bone cell formation and growth. Scaffolds made of metallic materials have preferably been chosen for bone tissue engineering applications where load-bearing capacities are required, considering the superior mechanical properties possessed by this type of materials to those of polymeric and ceramic materials. The space holder method has been recognized as one of the viable methods for the fabrication of metallic biomedical scaffolds. In this method, temporary powder particles, namely space holder, are devised as a pore former for scaffolds. In general, the whole scaffold fabrication process with the space holder method can be divided into four main steps: (i mixing of metal matrix powder and space-holding particles; (ii compaction of granular materials; (iii removal of space-holding particles; (iv sintering of porous scaffold preform. In this review, detailed procedures in each of these steps are presented. Technical challenges encountered during scaffold fabrication with this specific method are addressed. In conclusion, strategies are yet to be developed to address problematic issues raised, such as powder segregation, pore inhomogeneity, distortion of pore sizes and shape, uncontrolled shrinkage and contamination.

  9. [Application of new chest holder in the median sternotomy for open heart surgery in adults].

    Science.gov (United States)

    Xu, C Y; Feng, D G; Wang, J X; Cheng, Z Y; Wang, F; Lin, B; Xie, Z L; Suo, L N; Du, P

    2016-09-13

    Objective: To explore the application of new chest holder in the median sternotomy for open heart surgery in adults. Methods: Two hundred adult patients in Henan Provincial People's Hospital from May 2013 to May 2015 were enrolled in the study and randomly divided into two groups. Experimental group included 100 cases who accepted the new type of chest holder in the open heart surgery. Control group were also composed of 100 cases whose sternums were fixed with the pure steel wire cerclage. Sternal closure time was recorded since the sternum closing. All subjects were followed up to obtain the chest incision healing, the incidence of sternal dehiscence, infection and secondary thoracotomy, and thus to estimated the effect of new chest holder. Results: All patients in the experimental group reached the effect of firm closed chest surgery. Sternal closure time of experimental group was much shorter than that of control group[(10±2) vs (21±4) min, Pholder in the median sternotomy for open heart surgery is more convenient with small surgical trauma. It can also effectively reduce the incidence of sternal instability, dehiscence, infection and secondary thoracotomy.

  10. Effect of cavity flame holder configuration on combustion flow field performance of integrated hypersonic vehicle

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    As one of the most common methods to be used as the flame holding mechanism in the propulsion system of the integrated hypersonic vehicle,the research of cavity flame holder has drawn an ever increasing attention of many researchers. The two-dimensional coupled implicit NS equations,the standard k-ε turbulent models and the finite-rate/eddy-dissipation reaction model were employed to simulate the experimental items arranged by the orthogonal design,and the variance analysis method was used to investigate the effects of the geometric parameters of the cavity flame holder on the aero-propulsive performance of the integrated hypersonic vehicle,namely the depth,the ratio of length-to-depth and the sweepback angle. The obtained results show that the geometric parameters make only a little difference to the aero-propulsive performance of the vehicle in the range considered in this paper,and the cavity flame holder with its sweepback angle 45° can satisfy the performance requirement of the integrated hypersonic vehicle further. The hydrogen injected from the upper stream of the cavity makes the boundary layer separate on the lower wall of the engine,and a separate region appears in the upper stream and down stream of the injection slot,respectively.

  11. STEM tomography for thick biological specimens

    Energy Technology Data Exchange (ETDEWEB)

    Aoyama, Kazuhiro [FEI Company Japan Ltd., Application Laboratory, NSS-II Building, 2-13-34 Kohnan, Minato-ku, Tokyo 108-0075 (Japan)], E-mail: kazuhiro.aoyama@fei.com; Takagi, Tomoko [FEI Company Japan Ltd., Application Laboratory, NSS-II Building, 2-13-34 Kohnan, Minato-ku, Tokyo 108-0075 (Japan); Laboratory of Electron Microscopy, Japan Women' s University, 2-8-1 Mejirodai, Bunkyo-ku, Tokyo 112-8681 (Japan); Hirase, Ai; Miyazawa, Atsuo [Bio-multisome Research Team, RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); CREST, JST (Japan)

    2008-12-15

    Scanning transmission electron microscopy (STEM) tomography was applied to biological specimens such as yeast cells, HEK293 cells and primary culture neurons. These cells, which were embedded in a resin, were cut into 1-{mu}m-thick sections. STEM tomography offers several important advantages including: (1) it is effective even for thick specimens, (2) 'dynamic focusing', (3) ease of using an annular dark field (ADF) mode and (4) linear contrasts. It has become evident that STEM tomography offers significant advantages for the observation of thick specimens. By employing STEM tomography, even a 1-{mu}m-thick specimen (which is difficult to observe by conventional transmission electron microscopy (TEM)) was successfully analyzed in three dimensions. The specimen was tilted up to 73 deg. during data acquisition. At a large tilt angle, the specimen thicknesses increase dramatically. In order to observe such thick specimens, we introduced a special small condenser aperture that reduces the collection angle of the STEM probe. The specimen damage caused by the convergent electron beam was expected to be the most serious problem; however, the damage in STEM was actually smaller than that in TEM. In this study, the irradiation damage caused by TEM- and STEM-tomography in biological specimens was quantitatively compared.

  12. Molecular dynamics simulation of nano-indentation on Ti-V multilayered thin films

    Science.gov (United States)

    Feng, Chao; Peng, Xianghe; Fu, Tao; Zhao, Yinbo; Huang, Cheng; Wang, Zhongchang

    2017-03-01

    We developed a second nearest-neighbor modified embedded-atom method potential for binary Ti-V system. The potential parameters were identified by fitting the lattice parameter, cohesive energy and elastic constants of CsCl-type TiV, and further validated by reproducing the fundamental physical and mechanical properties of Ti-V systems with other crystal structures. In addition, we also performed molecular dynamics simulations of nano-indentation processes of pure Ti film, pure V film, and two kinds of four-layer Ti-V films, V-Ti-V-Ti and Ti-V-Ti-V. We found that the indentation force-depth curve for the pure V film turns flat at an indentation depth of 2.8 nm, where a prismatic loop was observed. Such prismatic loop is not found in the V/Ti/V/Ti multilayer because the thickness of each layer is insufficient for the formation of such prismatic loops, which accounts for the increase of stress in the multilayer.

  13. Surface analysis and mechanical behaviour mapping of vertically aligned CNT forest array through nanoindentation

    Science.gov (United States)

    Koumoulos, Elias P.; Charitidis, C. A.

    2017-02-01

    Carbon nanotube (CNT) based architectures have increased the scientific interest owning to their exceptional performance rendering them promising candidates for advanced industrial applications in the nanotechnology field. Despite individual CNTs being considered as one of the most known strong materials, much less is known about other CNT forms, such as CNT arrays, in terms of their mechanical performance (integrity). In this work, thermal chemical vapor deposition (CVD) method is employed to produce vertically aligned multiwall (VA-MW) CNT carpets. Their structural properties were studied by means of scanning electron microscopy (SEM), X-Ray diffraction (XRD) and Raman spectroscopy, while their hydrophobic behavior was investigated via contact angle measurements. The resistance to indentation deformation of VA-MWCNT carpets was investigated through nanoindentation technique. The synthesized VA-MWCNTs carpets consisted of well-aligned MWCNTs. Static contact angle measurements were performed with water and glycerol, revealing a rather super-hydrophobic behavior. The structural analysis, hydrophobic behavior and indentation response of VA-MWCNTs carpets synthesized via CVD method are clearly demonstrated. Additionally, cycle indentation load-depth curve was applied and hysteresis loops were observed in the indenter loading-unloading cycle due to the local stress distribution. Hardness (as resistance to applied load) and modulus mapping, at 200 nm of displacement for a grid of 70 μm2 is presented. Through trajection, the resistance is clearly divided in 2 regions, namely the MWCNT probing and the in-between area MWCNT - MWCNT interface.

  14. Evaluation of elastic modulus and hardness of crop stalks cell walls by nano-indentation.

    Science.gov (United States)

    Wu, Yan; Wang, Siqun; Zhou, Dingguo; Xing, Cheng; Zhang, Yang; Cai, Zhiyong

    2010-04-01

    Agricultural biomaterials such as crop stalks are natural sources of cellulosic fiber and have great potential as reinforced materials in bio-composites. In order to evaluate their potential as materials for reinforcement, the nano-mechanical properties of crop-stalk cell walls, i.e. those of cotton (Gossypium herbaceu) stalk, soybean (Glycine max) stalk, cassava (Manihot esculent) stalk, rice (Oryza sativa L.) straw, and wheat (Triticum aestivum L.) straw, were investigated by means of nano-indentation and atomic force microscopy (AFM). The elastic modulus of wheat straw was found to be 20.8 GPa, which was higher than that of the other four crops. The highest hardness was observed in cotton stalk at 0.85 GPa. The elastic moduli of the crop stalks were lower than those of most of the hardwood species, but higher than that of some softwoods and of lyocell fiber. The mean value of the hardness of the five crop stalks' cell walls was higher than those of wood or lyocell fiber.

  15. Variations of mechanical property of out circumferential lamellae in cortical bone along the radial by nanoindentation

    Directory of Open Access Journals (Sweden)

    Xingdong Sun

    2016-11-01

    Full Text Available Because the out circumferential lamellae have a special protective effect on the cortical bone, it is very important to understand the variations of the mechanical property of the out circumferential lamellae in cortical bone. For the purpose, the elasticity modulus and hardness of out circumferential lamellae in cortical bone were investigated in two orthogonal planes by nanoindentation, and the comparisons were made for both elasticity modulus and hardness between the two orthogonal planes. From the experiments, the decreasing trend was discovered for elasticity modulus from inside to outside in the transverse plane and ruleless variations tendency was presented in the longitudinal plane. The hardness presented the same variations in two orthogonal planes with elasticity modulus in respective plane. In the same layer, the elasticity modulus in the transverse plane was higher than that in the longitudinal plane, and the difference values between them turned to be smaller. In contrast, the hardness in the longitudinal plane was higher than that in the transverse plane in all the layers. From the heterogeneity and the microstructure of the material, the influence factors were discussed. A soft to hard structure model was put forward, and the coordinating protection mechanism of buffer and support was described. Investigation of variations of mechanical properties of out circumferential lamellae in cortical bone can provide some new understanding in researches of fracture of bone, interface load effect and design of bone graft.

  16. Nanoindentation characterization of the micro-lamellar arrangement of black coral skeleton.

    Science.gov (United States)

    Juárez-de la Rosa, B A; Muñoz-Saldaña, J; Torres-Torres, D; Ardisson, P-L; Alvarado-Gil, J J

    2012-02-01

    Black corals (antipatharians) are colonial cnidarians whose branched tree-like skeleton is mostly constituted of chitin fibrils inside a lipoproteic matrix. The skeleton exhibits growth rings formed by chitin layers (micro-lamellae). In order to know the effect of the arrangement microlamellae of chitin of black corals and to improve the understanding of the role of chitin structure in the antipatharian skeleton, the mechanical properties of the skeleton of two black corals, Antipathes caribbeana and Antipathes pennacea, were examined using nanoindentation tests. Measurements of reduced elastic modulus, nanohardness and the viscoelastic behavior were measured with a spheroconical indenter. The results indicate variations in the values of the mechanical properties clearly associated with different structures present in the skeletons, the core being the one that invariably shows the maximum values. The solid multilamellar arrangement of black coral chitin, its viscoelastic behavior, and the anisotropic mechanical response, are relevant factors contributing to the successful adaptation of black coral colonies to shallow as well as to very deep waters.

  17. Serrated flow behaviors of a Zr-based bulk metallic glass by nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, L.; Jiao, Z. M.; Ma, S. G.; Wang, Z. H., E-mail: qiaojunwei@gmail.com, E-mail: wangzhihua@tyut.edu.cn [Institute of Applied Mechanics and Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Qiao, J. W., E-mail: qiaojunwei@gmail.com, E-mail: wangzhihua@tyut.edu.cn [Institute of Applied Mechanics and Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Laboratory of Applied Physics and Mechanics of Advanced Materials, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China)

    2014-02-28

    Instrumented nanoindentation tests were used to investigate the mechanical properties of Zr{sub 52.5}Cu{sub 17.9}Ni{sub 14.6}Al{sub 10}Ti{sub 5} bulk metallic glass. The corresponding loading strain rates were ranged from 0.002 s{sup −1}, 0.02 s{sup −1} to 0.2 s{sup −1}. Plastic flow of this material exhibited remarkable serrations at low strain rates and increasingly became weakening until disappearance with increasing indentation strain rate, implying strong rate sensitivity. A significant pile-up around the indents was observed through atomic force microscopy, which suggested a highly localized plastic deformation. Mechanism governing the deformation was tentatively discussed in terms of the increasing process of free volume with a negligible temperature rise under low strain rate, which well explained the declining trend of elastic modulus and hardness with an increase of indentation depth.

  18. Nanoindentation study of the mechanical behavior of TiO{sub 2} nanotube arrays

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Y. N.; Wang, M. C.; Oloyede, A.; Bell, J. M.; Yan, C., E-mail: c2.yan@qut.edu.au [School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Brisbane, Queensland 4001 (Australia); Liu, M. N. [i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Science, Suzhou (China)

    2015-10-14

    Titanium dioxide (TiO{sub 2}) nanotube arrays are attracting increasing attention for use in solar cells, lithium-ion batteries, and biomedical implants. To take full advantage of their unique physical properties, such arrays need to maintain adequate mechanical integrity in applications. However, the mechanical performance of TiO{sub 2} nanotube arrays is not well understood. In this work, we investigate the deformation and failure of TiO{sub 2} nanotube arrays using the nanoindentation technique. We found that the load–displacement response of the arrays strongly depends on the indentation depth and indenter shape. Substrate-independent elastic modulus and hardness can be obtained when the indentation depth is less than 2.5% of the array height. The deformation mechanisms of TiO{sub 2} nanotube arrays by Berkovich and conical indenters are closely associated with the densification of TiO{sub 2} nanotubes under compression. A theoretical model for deformation of the arrays under a large-radius conical indenter is also proposed.

  19. Sensing inhomogeneous mechanical properties of human corneal Descemet's membrane with AFM nano-indentation.

    Science.gov (United States)

    Di Mundo, Rosa; Recchia, Giuseppina; Parekh, Mohit; Ruzza, Alessandro; Ferrari, Stefano; Carbone, Giuseppe

    2017-10-01

    The paper describes a highly space-resolved characterization of the surface mechanical properties of the posterior human corneal layer (Descemet's membrane). This has been accomplished with Atomic Force Microscopy (AFM) nano-indentation by using a probe with a sharp tip geometry. Results indicate that the contact with this biological tissue in liquid occurs with no (or very low) adhesion. More importantly, under the same operating conditions, a broad distribution of penetration depth can be measured on different x-y positions of the tissue surface, indicating a high inhomogeneity of surface stiffness, not yet clearly reported in the literature. An important contribution to such inhomogeneity should be ascribed to the discontinuous nature of the collagen/proteoglycans fibers matrix tissue, as can be imaged by AFM when the tissue is semi-dry. Using classical contact mechanics calculations adapted to the specific geometry of the tetrahedral tip it has been found that the elastic modulus E of the material in the very proximity of the surface ranges from 0.23 to 2.6 kPa. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    Nardi, Tommaso; Hammerquist, Chad; Nairn, John; Karimi, Ayat; Manson, Jan-Anders; Leterrier, Yves

    2015-08-01

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

  1. Activation energy of the low-load NaCl transition from nanoindentation loading curves.

    Science.gov (United States)

    Kaupp, Gerd

    2014-01-01

    Access to activation energies E(a) of phase transitions is opened by unprecedented analyses of temperature dependent nanoindentation loading curves. It is based on kinks in linearized loading curves, with additional support by coincidence of kink and electrical conductivity of silicon loading curves. Physical properties of B1, B2, NaCl and further phases are discussed. The normalized low-load transition energy of NaCl (Wtrans/µN) increases with temperature and slightly decreases with load. Its semi-logarithmic plot versus T obtains activation energy E(a)/µN for calculation of the transition work for all interesting temperatures and pressures. Arrhenius-type activation energy (kJ/mol) is unavailable for indentation phase transitions. The E(a) per load normalization proves insensitive to creep-on-load, which excludes normalization to depth or volume for large temperature ranges. Such phase transition E(a)/µN is unprecedented material's property and will be of practical importance for the compatibility of composite materials under impact and further shearing interactions at elevated temperatures.

  2. Nanoindentation and atomic force microscopy measurements on reactively sputtered TiN coatings

    Indian Academy of Sciences (India)

    Harish C Barshilia; K S Rajam

    2004-02-01

    Titanium nitride (TiN) coatings were deposited by d.c. reactive magnetron sputtering process. The films were deposited on silicon (111) substrates at various process conditions, e.g. substrate bias voltage (B) and nitrogen partial pressure. Mechanical properties of the coatings were investigated by a nanoindentation technique. Force vs displacement curves generated during loading and unloading of a Berkovich diamond indenter were used to determine the hardness () and Young’s modulus () of the films. Detailed investigations on the role of substrate bias and nitrogen partial pressure on the mechanical properties of the coatings are presented in this paper. Considerable improvement in the hardness was observed when negative bias voltage was increased from 100–250 V. Films deposited at |B| = 250 V exhibited hardness as high as 3300 kg/mm2. This increase in hardness has been attributed to ion bombardment during the deposition. The ion bombardment considerably affects the microstructure of the coatings. Atomic force microscopy (AFM) of the coatings revealed fine-grained morphology for the films prepared at higher substrate bias voltage. The hardness of the coatings was found to increase with a decrease in nitrogen partial pressure.

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

    Directory of Open Access Journals (Sweden)

    Tommaso eNardi

    2015-08-01

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

  4. Temperature dependent mechanical property of PZT film: an investigation by nanoindentation.

    Directory of Open Access Journals (Sweden)

    Yingwei Li

    Full Text Available Load-depth curves of an unpoled Lead Zirconate Titanate (PZT film composite as a function of temperature were measured by nanoindentation technique. Its reduce modulus and hardness were calculated by the typical Oliver-Pharr method. Then the true modulus and hardness of the PZT film were assessed by decoupling the influence of substrate using methods proposed by Zhou et al. and Korsunsky et al., respectively. Results show that the indentation depth and modulus increase, but the hardness decreases at elevated temperature. The increasing of indentation depth and the decreasing of hardness are thought to be caused by the decreasing of the critical stress needed to excite dislocation initiation at high temperature. The increasing of true modulus is attributed to the reducing of recoverable indentation depth induced by back-switched domains. The influence of residual stress on the indentation behavior of PZT film composite was also investigated by measuring its load-depth curves with pre-load strains.

  5. Hot stage nanoindentation in multi-component Al-Ni-Si alloys: Experiment and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Richter, A. [Institute of Polymer Technology and Materials Engineering, Loughborough University, Loughborough LE11 3TU (United Kingdom); Department of Engineering, University of Applied Sciences Wildau (Berlin), Bahnhofstrasse 1, Wildau 15745 (Germany)], E-mail: asta.richter@tfh-wildau.de; Chen, C.-L. [Institute of Polymer Technology and Materials Engineering, Loughborough University, Loughborough LE11 3TU (United Kingdom); Smith, R.; McGee, E. [Department of Mathematical Sciences, Loughborough University, Loughborough LE11 3TU (United Kingdom); Thomson, R.C. [Institute of Polymer Technology and Materials Engineering, Loughborough University, Loughborough LE11 3TU (United Kingdom); Kenny, S.D. [Department of Mathematical Sciences, Loughborough University, Loughborough LE11 3TU (United Kingdom)

    2008-10-25

    The mechanical properties of individually pure and intermetallic phases of typical Al-Ni-Si piston alloys are investigated at different temperatures using hot stage nanoindentation. The hardness and the indentation modulus of a number of phases are determined at room temperature, 500 K and 650 K. Both, hardness and reduced modulus drop with increasing temperature in different ratios for the various phases. Increasing Ni content in the grains improves the mechanical stability of the material at elevated temperatures in general. The indentation patterns are studied using atomic force microscopy with particular reference to the indentation depths and pile-up effects. Site-specific samples from the material surrounding the nanoindents are prepared using a focussed ion beam field emission gun for examination in the transmission electron microscope. This allows direct observation of material changes as a result of the indentation process in the different phases within the alloy system. Corresponding linked atomistic finite element calculations have been carried out for Si and Ni-Al systems as a function of increasing Ni content at various temperatures. The results show only a small difference in the mechanical behaviour of Si between 300 K and 650 K as observed in the experiments. Large differences for Al at both temperatures studied result in an increase of plasticity with rising temperature and atomic motion that changes from slip in well-defined planes to a viscous fluid-like behaviour. The formation of dislocations and slip bands during indentation for the Ni-Al systems is studied.

  6. Obtention of the constitutive equation of hydride blisters in fuel cladding from nanoindentation tests

    Science.gov (United States)

    Martin Rengel, M. A.; Gomez, F. J.; Rico, A.; Ruiz-Hervias, J.; Rodriguez, J.

    2017-04-01

    It is well known that the presence of hydrides in nuclear fuel cladding may reduce its mechanical and fracture properties. This situation may be worsened as a consequence of the formation of hydride blisters. These blisters are zones with an extremely high hydrogen concentration and they are usually associated to the oxide spalling which may occur at the outer surface of the cladding. In this work, a method which allows us to reproduce, in a reliable way, hydride blisters in the laboratory has been devised. Depth-sensing indentation tests with a spherical indenter were conducted on a hydride blister produced in the laboratory with the aim of measuring its mechanical behaviour. The plastic stress-strain curve of the hydride blister was calculated for first time by combining depth-sensing indentation tests results with an iterative algorithm using finite element simulations. The algorithm employed reduces, in each iteration, the differences between the numerical and the experimental results by modifying the stress-strain curve. In this way, an almost perfect adjustment of the experimental data was achieved after several iterations. The calculation of the constitutive equation of the blister from nanoindentation tests, may involve a lack of uniqueness. To evaluate it, a method based on the optimization of parameters of analytical equations has been proposed in this paper. An estimation of the error which involves this method is also provided.

  7. Universal scaling laws for homogeneous dislocation nucleation during nano-indentation

    Science.gov (United States)

    Garg, Akanksha; Maloney, Craig E.

    2016-10-01

    We perform atomistic simulations to study the mechanism of homogeneous dislocation nucleation in two dimensional (2D) hexagonal crystals during nanoindentation with a circular indenter of radius R. We study both a realistic embedded atom method (EAM) potential for Al in addition to simple pair-wise potentials: Lennard-Jones, Morse, and Hookean springs. The nucleation process is governed by the vanishing of the energy associated with a single energy eigenmode. The critical eigenmode, or dislocation embryo, is found to be localized along a line (or plane in 3D) of atoms with a lateral extent, ξ, at some depth, Y*, below the surface. For all interatomic potentials, the scaled critical load, Fc / R, and scaled critical contact length, Cc / R, decrease to R-independent values in the limit of large R. However, ξ / R and Y* / R display non-trivial scaling with R despite the R independence of Fc / R and Cc / R. We show that although both the interaction potential and the orientation of the lattice affect the prefactors in the scaling relations, all the scaling laws are robust. Furthermore, we show that a stability criterion proposed by Van Vliet et al. based on the minimum eigenvalue, Λ, of the local acoustic tensor predicts the location, orientation, and polarization of the dislocation embryo with a high degree of accuracy for all potentials and crystallographic orientations. However, we also show that, for all crystallographic orientations and interaction potentials, Λ erroneously indicates instability before the true instability occurs.

  8. The application of nanoindentation for determination of cellulose nanofibrils (CNF) nanomechanical properties

    Science.gov (United States)

    Yildirim, N.; Shaler, S.

    2016-10-01

    Nanocellulose is a polymer which can be isolated from nature (woods, plants, bacteria, and from sea animals) through chemical or mechanical treatments, as cellulose nanofibrils (CNF), cellulose nanocrystals or bacterial celluloses. Focused global research activities have resulted in decreasing costs. A nascent industry of producers has created a huge market interest in CNF. However, there is still lack of knowledge on the nanomechanical properties of CNF, which create barriers for the scientist and producers to optimize and predict behavior of the final product. In this research, the behavior of CNF under nano compression loads were investigated through three different approaches, Oliver-Pharr (OP), fused silica (FS), and tip imaging (TI) via nanoindentation in an atomic force microscope. The CNF modulus estimates for the three approaches were 16.6 GPa, for OP, 15.8 GPa for FS, and 10.9 GPa for TI. The CNF reduced moduli estimates were consistently higher and followed the same estimate rankings by analysis technique (18.2, 17.4, and 11.9 GPa). This unique study minimizes the uncertainties related to the nanomechanical properties of CNFs and provides increased knowledge on understanding the role of CNFs as a reinforcing material in composites and also improvement in making accurate theoretical calculations and predictions.

  9. Microtiter plate-sized standalone chip holder for microenvironmental physiological control in gas-impermeable microfluidic devices.

    Science.gov (United States)

    Harink, Björn; Le Gac, Séverine; Barata, David; van Blitterswijk, Clemens; Habibovic, Pamela

    2014-06-07

    We present a microtiter plate-sized standalone chip holder for precise control of physiological conditions inside closed microfluidic cell culture systems, made from gas-impermeable materials. Specifically, we demonstrate the suitability of the holder to support cell growth in a glass chip, to allow time-lapse imaging of live cells and the creation of a hypoxic environment, all relevant for applications in regenerative medicine research.

  10. Komedien holder

    DEFF Research Database (Denmark)

    Eigtved, Michael

    2011-01-01

    Programartikel til Det Kongelige Teaters opførelse af Molieres Den Gerrige, med fokus på komediens og komikkens status i nutiden, især mhp den nyere tv-komik.......Programartikel til Det Kongelige Teaters opførelse af Molieres Den Gerrige, med fokus på komediens og komikkens status i nutiden, især mhp den nyere tv-komik....

  11. Resistor holder

    Science.gov (United States)

    Broadhurst, John H.

    1989-01-01

    A resistor device for use with electrostatic particle accelerators includes a resistor element positioned within a tubular housing having a fixed end cap at one end thereof and a movable end cap at the other end thereof. The tubular housing, fixed end cap, and movable end cap serve as an electromagnetic field for the resistor element. Conductive disks engage opposite ends of the resistor element and concentrically position the resistor element within the tubular housing. Helical springs engage the conductive disks and the end caps to yieldably support the movable end caps and resistor element for yieldable axial movement relative to the tubular housing. An annular conducting ring is secured to the tubular housing and is spaced radially from the movable end cap and cooperates with the latter to define an annular spark gap.

  12. Nanoindentation analysis of the pop-in events on SiGe single layer

    Science.gov (United States)

    Lian, Derming

    2013-12-01

    The growth of metastable silicon germanium (Si0.8Ge0.2) thin film on Si(1 0 0) by ultrahigh-vacuum chemical vapor deposition has been subjected to residual indentation studies. A nanoindentation system has been applied to analyze SiGe film after different annealing treatments. A number of phenomena have been found for the heteroepitaxial growth of SiGe film at the critical thickness of 350 nm, including single discontinuity (the so-called "pop-in" event) as well as the elastic/plastic contact translation. Atomic force microscopy is employed to investigate the surface impression. Pop-in events in the load-indentation depth curves of 400 and 500 °C and no nano-cracks in the vicinity regions are found. The values of H ranging from 13.13±0.9, 21.66±1.3, 18.52±1.1, 14.47±0.7 GPa and the values of E ranging from 221.8±5.3, 230.7±6.4, 223.5±4.6, 156.7±3.8 GPa, are obtained. The elastic/plastic contact translation of the SiGe film occurs at different annealing conditions, with hf/hmax values in the range of 0.501, 0.392, 0.424, and 0.535 for samples are treated at RT, 400, 500, and 600 °C, respectively. The mechanism responsible for the pop-in event in such crystal structure is due to the interaction of the indenter tip with the pre-existing threading dislocations, since the release of the indentation load is bound to be reflected in the directly compressed volume.

  13. Microstructure and nanoindentation of the CLAM steel with nanocrystalline grains under Xe irradiation

    Science.gov (United States)

    Chang, Yongqin; Zhang, Jing; Li, Xiaolin; Guo, Qiang; Wan, Farong; Long, Yi

    2014-12-01

    This work presents an early look at irradiation effects on China low activation martensitic (CLAM) steel with nanocrystalline grains (NC-CLAM steels) under 500 keV Xe-ion bombardment at room temperature to doses up to 5.3 displacements per atom (dpa). The microstructure in the topmost region of the steel is composed of nanocrystalline grains with an average diameter of 13 nm. As the samples were implanted at low dose, the nanocrystalline grains had martensite lath structure, and many dislocations and high density bubbles were introduced into the NC-CLAM steels. As the irradiation dose up to 5.3 dpa, a tangled dislocation network exists in the lath region, and the size of the bubbles increases. X-ray diffraction results show that the crystal quality decreases after irradiation, although the nanocrystals obviously coarsen. Grain growth under irradiation may be ascribed to the direct impact of the thermal spike on grain boundaries in the NC-CLAM steels. In irradiated samples, a compressive stress exists in the surface layer because of grain growth and irradiation-introduced defects, while the irradiation introduced grain-size coarsening and defects gradients from the surface to matrix result in a tensile stress in the irradiated NC-CLAM steels. Nanoindentation was used to estimate changes in mechanical properties during irradiation, and the results show that the hardness of the NC-CLAM steels increases with increasing irradiation dose, which was ascribed to the competition between the grain boundaries and the irradiation-introduced defects.

  14. Mechanobiological Assessment of TMJ Disc Surfaces: Nanoindentation and Transmission Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Cassandra M. Juran

    2015-12-01

    Full Text Available Objectives: Temporomandibular disc is a mechanically robust fibrocartilage tissue exhibiting highly elastic compressive, shear, and tensile moduli with structurally dense extracellular matrix that supports functional loading of the joint. The aim of this study was to illustrate structural complexities of the superior and inferior disc surfaces, to demonstrate the robust mechanical ability of the disc as a whole may be due to depth-dependent regional/layered variation, and also to provide characterization data imperative for future tissue engineering efforts focused on restoring function to the joint. Material and Methods: Nanoindentation was used to assess tissue zones in conjunction with detailed Transmission Electron Microscopy to define structural attributes that influence the temporomandibular disc function. Results: The disc architecture adjacent to the superior surface was shown to have three distinct regional segments within the interface layer: 1-a surface peripheral layer; 2-subsurface region; and 3-a layer of helical matrix bundles. The inferior surface displayed an interface layer (20 µm that showed limited cell populations with little depth-dependent structural variation, a stiffer elastic modulus and reduced energy dissipation compared to the superior surface. These data indicate that the primary function of the inferior surface is resistance to compression rather than load distribution during joint motion. Conclusions: These are the first works that demonstrate that the superior central surface of the he temporomandibular disc is structured in depth-dependent isometric layers, each of which provides different mechanical function supporting the bulk tissue’s properties. From a clinical perspective these data have potential to define regions susceptible to fatigue that may translate to diagnostic criteria to better define the stages of dysfunction.

  15. Nanoindentation Characterization of a Ternary Clay-Based Composite Used in Ancient Chinese Construction

    Directory of Open Access Journals (Sweden)

    Dongwei Hou

    2016-10-01

    Full Text Available Ternary clay-based composite material (TCC, composed of lime, clay and sand, and usually modified with sticky rice and other organic compounds as additives, was widely used historically in Chinese construction and buildings due to its high mechanical performance. In this study, to gain an insight into the micromechanical mechanism of this cementitious material, the nanomechanical properties and volume fraction of mechanically different phases of the binder matrix are derived from the analysis of grid nanoindentation tests. Results show that there are five distinct mechanical phases, where the calcium silicate hydrate (C-S-H and geopolymer present in the binder matrix are almost identical to those produced in ordinary Portland cement (OPC and alkali-activated fly-ash geopolymer materials in nano-mechanical performance. The nano-mechanical behavior of calcite produced by the carbonation of lime in this binder is close to the calcite porous outer part of some sea urchin shells. Compared to OPC, the C-S-H contained in the TCC has a relatively lower ratio of indentation modulus to indentation hardness, implying a relatively lower resistance to material fracture. However, the geopolymer and calcite, at nearly the same volume content as the C-S-H, help to enhance the strength and durability of the TCC by their higher energy resistance capacity or higher strength compared to the C-S-H. Rediscovering of TCC offers a potential way to improve modern concrete’s strength and durability through synergy of multi-binders and the addition of organic materials if TCC can be advanced in terms of its workability and hardening rate.

  16. Reconstituted Charpy impact specimens. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Perrin, J.S.; Wullaert, R.A.; McConnell, P.; Server, W.L.; Fromm, E.O.

    1982-12-01

    The arc stud welding process was used to produce new, full size Charpy V-notch impact specimens from halves of Charpy specimens which had been previously tested. The apparatus was developed such that it could be used not only for unirradiated specimens, but also so that it could be adapted for in-cell use to produce new reconstituted specimens of irradiated material. The materials studied are of interest in nuclear applications. They include A533B, A36, A516-80, submerged arc weld metal (A508 base metal), HY80, cast duplex stainless steel, irradiated A533B, and irradiated submerged arc weld metal (A508 base metal). Both unirradiated and irradiated specimens were successfully produced and subsequently impact tested. In general, there was excellent agreement when comparing the original curves to the subsequent curves generated with reconstituted specimens. This program has shown that the arc stud welding process is well suited for producing reconstituted specimens at a reasonable cost using either unirradiated or irradiated material.

  17. Update of NIST half-life results corrected for ionization chamber source-holder instability.

    Science.gov (United States)

    Unterweger, M P; Fitzgerald, R

    2014-05-01

    As reported at the ICRM 2011, it was discovered that the source holder used for calibrations in the NIST 4πγ ionization chamber (IC) was not stable. This has affected a large number of half-life measurement results previously reported and used in compilations of nuclear data. Corrections have been made on all of the half-life data based on the assumption that the changes to the ionization chamber response were gradual. The corrections are energy dependent and therefore radionuclide specific. This presentation will review our results and present the recommended changes in half-life values and/or uncertainties.

  18. A Simple Refining Technique of Coconut Oil for Small Holder Industries

    OpenAIRE

    2009-01-01

    A simple refining equipment and process for small holder industries of edible coconut oil has beeninvestigated. The equipment consisted of 20-L filtering and NaOH neutralization bottles. Filtration wasintended to remove impurities such as gums and pigment, while neutralization was to remove free fattyacids (FFA) and other non-fat materials. In the experiment, the crude coconut oil was found to have impurityof 0.16%, FFA of 8.02%, saponification number of 270, and water content of 0.33%. The r...

  19. Structure of Wet Specimens in Electron Microscopy

    Science.gov (United States)

    Parsons, D. F.

    1974-01-01

    Discussed are past work and recent advances in the use of electron microscopes for viewing structures immersed in gas and liquid. Improved environmental chambers make it possible to examine wet specimens easily. (Author/RH)

  20. Testing Biopsy and Cytology Specimens for Cancer

    Science.gov (United States)

    ... Your Diagnosis Exams and Tests for Cancer Testing Biopsy and Cytology Specimens for Cancer Waiting to hear ... who tell you whether the cells in your biopsy sample are cancer or not. How is cancer ...

  1. Structure of Wet Specimens in Electron Microscopy

    Science.gov (United States)

    Parsons, D. F.

    1974-01-01

    Discussed are past work and recent advances in the use of electron microscopes for viewing structures immersed in gas and liquid. Improved environmental chambers make it possible to examine wet specimens easily. (Author/RH)

  2. The influence of yield surface shape and damage in the depth-dependent response of bone tissue to nanoindentation using spherical and Berkovich indenters.

    Science.gov (United States)

    Schwiedrzik, Johann Jakob; Zysset, Philippe Kurt

    2015-01-01

    Prevention and treatment of osteoporosis rely on understanding of the micromechanical behaviour of bone and its influence on fracture toughness and cell-mediated adaptation processes. Postyield properties may be assessed by nonlinear finite element simulations of nanoindentation using elastoplastic and damage models. This computational study aims at determining the influence of yield surface shape and damage on the depth-dependent response of bone to nanoindentation using spherical and conical tips. Yield surface shape and damage were shown to have a major impact on the indentation curves. Their influence on indentation modulus, hardness, their ratio as well as the elastic-to-total work ratio is well described by multilinear regressions for both tip shapes. For conical tips, indentation depth was not statistically significant (p damage was not a significant parameter (p < 0.0001). The gained knowledge can be used for developing an inverse method for identification of postelastic properties of bone from nanoindentation.

  3. Impact of specimen adequacy on the assessment of renal allograft biopsy specimens.

    Science.gov (United States)

    Cimen, S; Geldenhuys, L; Guler, S; Imamoglu, A; Molinari, M

    2016-01-01

    The Banff classification was introduced to achieve uniformity in the assessment of renal allograft biopsies. The primary aim of this study was to evaluate the impact of specimen adequacy on the Banff classification. All renal allograft biopsies obtained between July 2010 and June 2012 for suspicion of acute rejection were included. Pre-biopsy clinical data on suspected diagnosis and time from renal transplantation were provided to a nephropathologist who was blinded to the original pathological report. Second pathological readings were compared with the original to assess agreement stratified by specimen adequacy. Cohen's kappa test and Fisher's exact test were used for statistical analyses. Forty-nine specimens were reviewed. Among these specimens, 81.6% were classified as adequate, 6.12% as minimal, and 12.24% as unsatisfactory. The agreement analysis among the first and second readings revealed a kappa value of 0.97. Full agreement between readings was found in 75% of the adequate specimens, 66.7 and 50% for minimal and unsatisfactory specimens, respectively. There was no agreement between readings in 5% of the adequate specimens and 16.7% of the unsatisfactory specimens. For the entire sample full agreement was found in 71.4%, partial agreement in 20.4% and no agreement in 8.2% of the specimens. Statistical analysis using Fisher's exact test yielded a P value above 0.25 showing that - probably due to small sample size - the results were not statistically significant. Specimen adequacy may be a determinant of a diagnostic agreement in renal allograft specimen assessment. While additional studies including larger case numbers are required to further delineate the impact of specimen adequacy on the reliability of histopathological assessments, specimen quality must be considered during clinical decision making while dealing with biopsy reports based on minimal or unsatisfactory specimens.

  4. Vickers Microhardness Testing with Miniaturized Disk Specimens

    OpenAIRE

    Kurishita, Hiroaki; Kayano, Hideo

    1991-01-01

    The microhardness technique has been increasingly important for testing irradiated materials because of the necessity of small-scale specimen technology. In order to establish Vickers microhardness testing over a wide temperature range using miniaturized specimens such as transmission electron microscopy (TEM) disks, an apparatus that permits the measurements in the temperature range of well below liquid nitrogen temperature to well above room temperature is developed. Effects of indentation ...

  5. Ultrasonic analysis of spherical composite test specimens

    Energy Technology Data Exchange (ETDEWEB)

    Brosey, W.D.

    1984-08-22

    Filament wound spherical test specimens have been examined ultrasonically as part of a program to determine the effectiveness of various nondestructive evaluation techniques for analysis of mechanical characteristics of a composite with enclosed geometry. The Kevlar-epoxy composite specimens contained simulated defect conditions which were located, and the extent of damage determined, using ultrasonic analysis. Effects of transducer frequency and signal parameters have been examined to determine optimum conditions for flaw detection. The data were displayed in rectangular and axonometric projection.

  6. Warm Deep Drawing of Rectangular Parts of AZ31 Magnesium Alloy Sheet Adopting Variable Blank Holder Force

    Science.gov (United States)

    Ying-hong, Peng; Qun-feng, Chang; Da-yong, Li; Xiao-qin, Zeng

    2007-05-01

    AZ31 magnesium alloy sheet with good shape and formability is fabricated by warm cross rolling. Uniaxial tensile tests are conducted using a Gleeble 3500 thermal - mechanical simulator, and the mechanical properties of AZ31 magnesium alloy sheet are analyzed. A warm deep drawing process of square part is also simulated by the finite element method. The influences of blank holder force on the formability are numerically investigated. A double-action hydraulic press that can realize adjustable blank holder forces is developed and its working principle and control system are introduced. Some warm deep drawing experiments of square parts of AZ31 magnesium alloy sheet are also performed. Different variation schemes of the blank holder force with the stroke of the punch are tested, and the experiment results are compared. Results show that the suitable blank holder force variation scheme is a ladder curve with the punch stroke. Adopting the variable blank holder force technique can improve 13.2% of the drawing depth of square parts of AZ31 magnesium alloy sheet.

  7. The MAVID heart holder: a demonstration device to anchor cadaver hearts for surgical simulation and practical education.

    Science.gov (United States)

    Mavroudis, Constantine; Idriss, Rachid; Klaus, Kristen E

    2015-12-01

    Performing open heart surgery involves learning challenging techniques and a need for realistic training models to achieve and maintain a high level of surgical skills. The MAVID heart holder is an organ holder primarily designed to hold the heart in its anatomic position for the purpose of surgical simulation and education, thereby closing the gap between surgical performance in the laboratory and in the operating room. The device is simple to use, can be adjusted to organ size, and has the necessary instrumentation to be used with any solid organ. The MAVID heart holder also provides a platform for presentation and assists in advancing the research sphere. The advantage over other existing models is that the MAVID heart holder uses real tissue and does not distort the organ at the attachment sites. Further, it offers superior stability as well as the ability to manipulate the organ during presentation and dissection. Training with the MAVID heart holder has the potential to shorten training time to acquire surgical skills and proficiency before performing these techniques in the operating room and in so doing enhance patient safety.

  8. A novel way to estimate the nanoindentation hardness of only-irradiated layer and its application to ion irradiated Fe-12Cr alloy

    Science.gov (United States)

    Kim, Hoon-Seop; Lee, Dong-Hyun; Seok, Moo-Young; Zhao, Yakai; Kim, Woo-Jin; Kwon, Dongil; Jin, Hyung-Ha; Kwon, Junhyun; Jang, Jae-il

    2017-04-01

    While nanoindentation is a very useful tool to examine the mechanical properties of ion irradiated materials, there are some issues that should be considered in evaluating the properties of irradiated layer. In this study, in order to properly extract the hardness of only-irradiated layer from nanoindentation data, a new procedure is suggested in consideration of the geometry of indentation-induced plastic zone. By applying the procedure to an ion irradiated Fe-12Cr alloy, the reasonable results were obtained, validating its usefulness in the investigation of practical effect of irradiation on the mechanical behavior of future nuclear materials.

  9. Impact of the Flame-Holder Heat-Transfer Characteristics on the Onset of Combustion Instability

    KAUST Repository

    Hong, Seunghyuck

    2013-10-03

    In this article, we investigate the impact of heat transfer between the flame and the flameholder on the dynamic stability characteristics of a 50-kW backward-facing step combustor. We conducted a series of tests where two backward step blocks were used, made of ceramic and stainless steel, whose thermal conductivities are 1.06 and 12 W/m/K, respectively. Stability characteristics of the two flame-holder materials were examined using measurements of the dynamic pressure and flame chemiluminescence over a range of operating conditions. Results show that with the ceramic flameholder, the onset of instability is significantly delayed in time and, for certain operating conditions, disappears altogether, whereas with the higher conductivity material, the combustor becomes increasingly unstable over a range of operating conditions. We explain these trends using the heat flux through the flameholder and the change in the burning velocity near the step wall. Results suggest a potential approach using low-thermal-conductivity material near the flame-holder as passive dynamics suppression methods. Copyright © Taylor & Francis Group, LLC.

  10. Evaluation of the maxillary premolar roots dissociation using radiographic holders with conventional and digital radiography

    Directory of Open Access Journals (Sweden)

    Marcia Regina Ramalho da Silva Bardauil

    2010-09-01

    Full Text Available This in vivo study evaluated the dissociation quality of maxillary premolar roots combining variations of vertical and horizontal angulations by using X-ray holders (Rinn -XCP, and made a comparison between two types of intraoral radiography systems - conventional film (Kodak Insight, Rochester, USA and digital radiography (Kodak RVG 6100, Kodak, Rochester, USA. The study sample was comprised of 20 patients with a total of 20 maxillary premolars that were radiographed, using the paralleling angle technique (GP, with a 20º variation of the horizontal angle (GM and 25º variation of the horizontal angle combined with 15º vertical angle (GMV. Each image was independently analyzed by two experienced examiners. These examiners assigned a score to the diagnostic capability of root dissociation and the measurement of the distance between the apexes. Statistical data was derived using the Wilcoxon Signed Rank test, Friedman and T test. The means of the measured distances between buccal and lingual root apexes were greater for the GMV, which ranged from 2.3 mm to 3.3 mm. A statistically significant difference was found between GM and GMV when compared to GP with p < 0.01. An established best diagnostic dissociation roots image was found in the GMV. These results support the use of the anterior X-ray holders which offer a better combined deviation (GMV to dissociate maxillary premolar roots in both radiography systems.

  11. Volatile Constituents, Inorganic Elements and Primary Screening of Bioactivity of Black Coral Cigarette Holders

    Directory of Open Access Journals (Sweden)

    Ganggang Shi

    2011-05-01

    Full Text Available Black corals (BC have been used for a long time in Chinese medicine, and may have some pharmaceutical functions when used as material for cigarette holders in southeast China. This study is aimed to investigate the bioactivities of volatile constituents in BC and to explore the folklore behind the use of BC cigarette holders (BCCHs. We extracted the volatile constituents of BC by supercritical fluid extraction (SFE with carbon dioxide (CO2-SFE, then identified and analyzed the constituents by gas chromatography-mass spectrometry (GC-MS. In total, 15 components were reliably identified in BC and found to be biologically active. These included triethyl phosphate, butylated hydroxytoluene, cedrol, n-hexadecanoic acid, squalene, and cholesterol. Meanwhile 13 inorganic elements (P, Ca, Mg, S, B, Si, Fe, Cu, Zn, Ba, etc. were determined by inductively coupled plasma spectrometer (ICPS. In the bioactivity tests, the BC extract (BCE showed a scavenging activity of 2,2-diphenyl-1-picrylhydrazyl free radicals and hydroxyl radicals by phenanthroline-Fe (II oxidation and moderate inhibition of Gram-positive microorganisms. The antioxidant and antimicrobial activities of BC, which are related to the active chemical composition, may explain the perceived benefit for cigarette smokers who use BCCHs.

  12. Frimand Needle Holder Reduces Suturing Time and Surgical Stress When Suturing in Palm Grip.

    Science.gov (United States)

    Frimand Rönnow, Carl-Fredrik; Jeppsson, Bengt; Thorlacius, Henrik

    2016-06-01

    Purpose The Frimand needle holder (FNH) was developed to facilitate palm grip suturing. In the present study, we wanted to examine the impact of the FNH compared with a conventional Hegar-styled needle holder (HSNH) on suture time and surgical stress. Methods Thirty-two surgeons were enrolled and they performed sets of 3 continuous sutures on a polyurethane pad with premarked insert and exit points and the time for suturing was measured. Surgical stress was quantified by having the surgeons to perform 10 release maneuvers with the FNH and the HSNH on a needle attached to a scale. The scale sent 5 values per second to a computer. The first measurement of each series was regarded as the starting weight and all subsequent measurements were either regarded as neutral, pressure or traction. The sum of these measurements represented total surgical stress. Results We found that all surgeons reduced their median suturing time by 16% when using FNH for palm grip suturing with no difference between junior and senior surgeons. Moreover, it was observed that FNH decreased median surgical stress by 62% for all surgeons performing palm grip suturing compared with a conventional HSNH. Conclusion We conclude that the FNH reduces suture time and surgical stress compared with HSNH when performing palm grip suturing. These findings warrant studies in surgical patients in order to evaluate the potential clinical impact of FNH.

  13. Development of miniaturized light endoscope-holder robot for laparoscopic surgery

    CERN Document Server

    Long, Jean-Alexandre; Troccaz, Jocelyne; Voros, Sandrine; Descotes, Jean-Luc; Berkelman, Peter; Letoublon, Christian; Rambeaud, Jean-Jacques

    2007-01-01

    PURPOSE: We have conducted experiments with an innovatively designed robot endoscope holder for laparoscopic surgery that is small and low cost. MATERIALS AND METHODS: A compact light endoscope robot (LER) that is placed on the patient's skin and can be used with the patient in the lateral or dorsal supine position was tested on cadavers and laboratory pigs in order to allow successive modifications. The current control system is based on voice recognition. The range of vision is 360 degrees with an angle of 160 degrees . Twenty-three procedures were performed. RESULTS: The tests made it possible to advance the prototype on a variety of aspects, including reliability, steadiness, ergonomics, and dimensions. The ease of installation of the robot, which takes only 5 minutes, and the easy handling made it possible for 21 of the 23 procedures to be performed without an assistant. CONCLUSION: The LER is a camera holder guided by the surgeon's voice that can eliminate the need for an assistant during laparoscopic s...

  14. Rapid full-field OCT assessment of clinical tissue specimens (Conference Presentation)

    Science.gov (United States)

    Dalimier, Eugénie; Harms, Fabrice; Brossollet, Charles; Benoit, Emilie; Martins, Franck; Boccara, Claude A.

    2016-03-01

    FFOCT (Full Field Optical Coherence Tomography) is a novel optical technology that gives access to very high resolution tomography images of biological tissues within minutes, non-invasively. This makes it an attractive tool to bridge the gap between medical imaging modalities (MRI, ultrasound, CT) used for cancer lesion identification or targeting and histological diagnosis. Clinical tissue specimens, such as surgical cancer margins or biopsies, can potentially be assessed rapidly, by the clinician, in the aim to help him decide on the course of action. A fast FFOCT prototype was built, that provides 1cm2 images with 1 µm resolution in 1 minute, and can accommodate samples up to 50mm diameter. Specific work was carried out to implement a large sample holder, high-speed image acquisition system, optimized scanning, and accelerated GPU tiles stitching. Results obtained on breast, urology, and digestive tissues show the efficiency of the technique for the detection of cancer on clinical tissue specimens, and reinforce the clinical relevance of the technique. The technical and clinical results show that the fast FFOCT system can successfully be used for a fast assessment of cancer excision margins or biopsies providing a very valuable tool in the clinical environment.

  15. Closeout of JOYO-1 Specimen Fabrication Efforts

    Energy Technology Data Exchange (ETDEWEB)

    ME Petrichek; JL Bump; RF Luther

    2005-10-31

    Fabrication was well under way for the JOYO biaxial creep and tensile specimens when the NR Space program was canceled. Tubes of FS-85, ASTAR-811C, and T-111 for biaxial creep specimens had been drawn at True Tube (Paso Robles, CA), while tubes of Mo-47.5 Re were being drawn at Rhenium Alloys (Cleveland, OH). The Mo-47.5 Re tubes are now approximately 95% complete. Their fabrication and the quantities produced will be documented at a later date. End cap material for FS-85, ASTAR-811C, and T-111 had been swaged at Pittsburgh Materials Technology, Inc. (PMTI) (Large, PA) and machined at Vangura (Clairton, PA). Cutting of tubes, pickling, annealing, and laser engraving were in process at PMTI. Several biaxial creep specimen sets of FS-85, ASTAR-811C, and T-111 had already been sent to Pacific Northwest National Laboratory (PNNL) for weld development. In addition, tensile specimens of FS-85, ASTAR-811C, T-111, and Mo-47.5 Re had been machined at Kin-Tech (North Huntington, PA). Actual machining of the other specimen types had not been initiated. Flowcharts 1-3 detail the major processing steps each piece of material has experienced. A more detailed description of processing will be provided in a separate document [B-MT(SRME)-51]. Table 1 lists the in-process materials and finished specimens. Also included are current metallurgical condition of these materials and specimens. The available chemical analyses for these alloys at various points in the process are provided in Table 2.

  16. Atomistic simulation of tantalum nanoindentation: Effects of indenter diameter, penetration velocity, and interatomic potentials on defect mechanisms and evolution

    Energy Technology Data Exchange (ETDEWEB)

    Ruestes, C.J., E-mail: cjruestes@hotmail.com [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Facultad de Ciencias Exactas y Naturales, Univ. Nac. de Cuyo, Mendoza 5500 (Argentina); CONICET, Mendoza 5500 (Argentina); Stukowski, A. [Technische Universität Darmstadt, Darmstadt 64287 (Germany); Tang, Y. [Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200072 (China); Tramontina, D.R. [Facultad de Ciencias Exactas y Naturales, Univ. Nac. de Cuyo, Mendoza 5500 (Argentina); Erhart, P. [Chalmers University of Technology, Department of Applied Physics, Gothenburg 41296 (Sweden); Remington, B.A. [Lawrence Livermore National Lab, Livermore, CA 94550 (United States); Urbassek, H.M. [Physics Department and Research Center OPTIMAS, University of Kaiserslautern, Kaiserslautern 67663 (Germany); Meyers, M.A. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Bringa, E.M. [Facultad de Ciencias Exactas y Naturales, Univ. Nac. de Cuyo, Mendoza 5500 (Argentina); CONICET, Mendoza 5500 (Argentina)

    2014-09-08

    Nanoindentation simulations are a helpful complement to experiments. There is a dearth of nanoindentation simulations for bcc metals, partly due to the lack of computationally efficient and reliable interatomic potentials at large strains. We carry out indentation simulations for bcc tantalum using three different interatomic potentials and present the defect mechanisms responsible for the creation and expansion of the plastic deformation zone: twins are initially formed, giving rise to shear loop expansion and the formation of sequential prismatic loops. The calculated elastic constants as function of pressure as well as stacking fault energy surfaces explain the significant differences found in the defect structures generated for the three potentials investigated in this study. The simulations enable the quantification of total dislocation length and twinning fraction. The indenter velocity is varied and, as expected, the penetration depth for the first pop-in (defect emission) event shows a strain rate sensitivity m in the range of 0.037–0.055. The effect of indenter diameter on the first pop-in is discussed. A new intrinsic length-scale model is presented based on the profile of the residual indentation and geometrically necessary dislocation theory.

  17. Investigation of Interface Bonding Mechanism of an Explosively Welded Tri-Metal Titanium/Aluminum/Magnesium Plate by Nanoindentation

    Science.gov (United States)

    Zhang, T. T.; Wang, W. X.; Zhou, J.; Cao, X. Q.; Yan, Z. F.; Wei, Y.; Zhang, W.

    2017-08-01

    A tri-metal titanium/aluminum/magnesium (Ti/Al/Mg) cladding plate, with an aluminum alloy interlayer plate, was fabricated for the first time by explosive welding. Nanoindentation tests and associated microstructure analysis were conducted to investigate the interface bonding mechanisms of the Ti/Al/Mg cladding plate. A periodic wavy bonding interface (with an amplitude of approximately 30 μm and a wavelength of approximately 160 μm) without a molten zone was formed between the Ti and Al plates. The bonding interface between the Al and the Mg demonstrated a similar wavy shape, but the wave at this location was much larger with an amplitude of approximately 390 μm and a wavelength of approximately 1580 μm, and some localized melted zones also existed at this location. The formation of the wavy interface was found to result from a severe deformation at the interface, which was caused by the strong impact or collision. The nanoindentation tests showed that the material hardness decreased with increasing distance from the bonding interface. Material hardness at a location was found to be correlated with the degree of plastic deformation at that site. A larger plastic deformation was correlated with an increase in hardness.

  18. The phase stability and mechanical properties of Nb–C system: Using first-principles calculations and nano-indentation

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Lailei; Wang, Yachun; Yan, Zhigang; Zhang, Jingwu; Xiao, Furen [Key Laboratory of Metastable Materials Science and Technology, College of Material Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Liao, Bo, E-mail: wll@ysu.edu.cn [Key Laboratory of Metastable Materials Science and Technology, College of Material Science and Engineering, Yanshan University, Qinhuangdao 066004 (China)

    2013-06-05

    Highlights: ► Hardness and Young’s modulus of c-NbC have been evaluated by nano-indentation. ► The properties of Nb–C system have been studied by first-principles calculations. ► Pnma-Nb{sub 2}C and P3{sub 1}-Nb{sub 6}C{sub 5} are identified as ground state structures for Nb–C system. ► Four proposed Nb-C phases are stable energetically, mechanically, dynamically. -- Abstract: Structural stability and mechanical property of niobium carbide (NbC) were characterized by combined experimental methods and first-principles technique. The hardness and Young’s modulus were measured to be 24.5 GPa and 406 GPa for NbC from nano-indentation, respectively. Moreover, the systematically studies of the structural, mechanical, and electronic properties of niobium carbides show that pnma-Nb{sub 2}C and P3{sub 1}-Nb{sub 6}C{sub 5} are the ground state structures, consistent with the experiment results. The proposed Fm-3m-Nb{sub 23}C{sub 6}, Pnma-Nb{sub 3}C, C2/c-Nb{sub 5}C{sub 2}, and P6{sub 3}mc-Nb{sub 7}C{sub 3}, are stable energetically, mechanically, and dynamically from first-principles calculations. The effects of carbon content on the elastic modulus and theoretical hardness of niobium carbides were also discussed.

  19. 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.)

  20. Application of a dynamic-nanoindentation method to analyze the local structure of an Fe-18 at.% Gd cast alloy

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yong; Baik, Youl [Dept. of Materials Science and Technology, Dankook University, Cheonan(Korea, Republic of); Moon, Byung M. [Liquid Processing and Casting Technology R and D Group, KITECH, Incheon (Korea, Republic of); Sohn, Dong Seong [Nuclear Engineering Department, UNIST, Ulsan (Korea, Republic of)

    2017-04-15

    A dynamic nanoindentation method was applied to study an Fe-18 at.% Gd alloy as a neutron-absorbing material prepared by vacuum arc-melting and cast in a mold. The Fe-18 at.% Gd cast alloy had a microstructure with matrix phases and an Fe-rich primary dendrite of Fe9Gd. Rietveld refinement of the X-ray spectra showed that the Fe-18 at.% Gd cast alloy consisted of 35.84 at.% Fe3Gd, 6.58 at.% Fe5Gd, 16.22 at.% Fe9Gd, 1.87 at.% Fe2Gd, and 39.49 at.% β-Fe17Gd2. The average nanohardness of the primary dendrite phase and the matrix phases were 8.7 GPa and 9.3 GPa, respectively. The fatigue limit of the matrix phase was approximately 37% higher than that of the primary dendrite phase. The dynamic nanoindentation method is useful for identifying local phases and for analyzing local mechanical properties.

  1. Assessment of bulk and surface properties of medical grade UHMWPE based nanocomposites using Nanoindentation and microtensile testing.

    Science.gov (United States)

    Rama Sreekanth, P S; Kanagaraj, S

    2013-02-01

    A thrust on the enhancement of the mechanical properties of ultra high molecular weight polyethylene (UHMWPE) to enhance its longevity has taken a new direction with the advent of nanomaterials and carbon nanotubes. In the present work, UHMWPE was reinforced by chemically treated multi walled carbon nanotubes (MWCNTs) at different concentrations such as 0.5, 1.0, 1.5, 2.0, 2.5 and 5 wt%. The mechanical properties of nanocomposites were studied using a Nanoindentation technique and micro-tensile testing. It is observed that the toughness, ultimate stress, fracture strain, and yield stress of medical grade UHMWPE were enhanced by 176, 93, 70, and 44%, respectively at an optimum concentration of 2 wt% MWCNTs reinforcement. The mechanism for the enhancement of mechanical properties was confirmed by the micro-Raman and calorimetric technique. The reduction of the mechanical properties of nanocomposites beyond optimum concentration of MWCNTs was confirmed by the rheological studies. The generation of microvoids on the nanocomposites was verified by the scanning electron microscopy technique. Nanoindentation characteristics revealed that the surface hardness of UHMWPE was increased by 75% by the reinforcement of 2 wt% of MWCNTs. The Young's modulus obtained at the surface of nanocomposites was observed to be 9.8% higher than that of surface layer removed sample for 2 wt% nanocomposite. It is concluded that the presence of MWCNTs enhanced the mechanical properties and surface properties of medical grade UHMWPE.

  2. Cross-sectional nanoindentation (CSN) studies on the effect of thickness on adhesion strength of thin films

    Science.gov (United States)

    Roshanghias, A.; Khatibi, G.; Pelzer, R.; Steinbrenner, J.; Bernardi, J.

    2015-01-01

    In this study the cross-sectional nanoindentation (CSN) technique has been employed to investigate the adhesion behavior of Titanium-Tungsten (TiW) thin films in various thicknesses on silicon substrate. Furthermore, the nanoindentation-induced blister (NIB) technique has been implemented on the same samples to evaluate the adhesion energy of the films with a different approach. The adhesion energy release rate of these thin films, derived by these two techniques, revealed a good agreement. Accordingly, the results show that as the thickness of the TiW layer increases, the adhesion toughness of the film decreases. It was suggested that three factors might be responsible for the superior adhesion strength of thin films with lower thicknesses: higher surface energy due to the smaller mean grain size; higher constraint from the substrate, which causes inferior fracture toughness of the coating and facilitates crack deflection from interface to surface; and, energy dissipation due to decohesion. The thickness dependency of the transition between delamination and decohesion mechanism in thin films has also been discussed and modelled.

  3. 具有混合光滑性的Holder-Nikolskii-Wiener类在Lq(Rd)中的平均宽度(英文)%Average Width of Holder-Nikolskii-Wiener Classes With Mixed Smoothness in Lq(Rd)

    Institute of Scientific and Technical Information of China (English)

    汪和平

    2002-01-01

    In this paper, the average σ- K width of Holder-Nikolskii-Wiener classes ST pq H with mixed smoothness in Lq(Rd) is studied for 2 ≤ q ≤ p <∞, and the weak asymptotical behavior of these quantities is obtained.%本文研究了具有混合光滑性的Holder-Nikolskii-Wiener类S r pq日在Lq(Rd)中的平均σ-K宽度(2≤q ≤ p<∞),得到了该量的弱渐近估计.

  4. Research on parameters optimization of bilateral ring gear blank-holder in thick-plate fine blanking

    Directory of Open Access Journals (Sweden)

    C.J.Su

    2014-10-01

    Full Text Available To compensate for the poor quality of thick-plate blanking parts in cross-section, this paper suggests using the optimizing bilateral ring gear holder parameters to increase burnish zone and improve cutting precision. With the bilateral gear ring, the hydrostatic pressure of shear deformation zone will increase, plasticity of the material will be lifted to maximum and quality of the cross section will be raised. This paper establishes 8mm AISI-1020 fine blanking model by DEFORM2D, analysis different ring gear parameters and clearance that are influenced the stress-strain and cross section quality to predict forming defects. By using the bilateral gear ring blank holder, the poor quality of thick-plate blanking section is successfully enhanced. Therefore, the bilateral gear ring blank holder is vital to improve the quality of blanking parts and provide the reliable theory basis for the practical engineering application.

  5. Investigation of holder pressure and size effects in micro deep drawing of rectangular work pieces driven by piezoelectric actuator.

    Science.gov (United States)

    Aminzahed, Iman; Mashhadi, Mahmoud Mosavi; Sereshk, Mohammad Reza Vaziri

    2017-02-01

    Micro forming is a manufacturing process to fabricate micro parts with high quality and a cost effective manner. Deep drawing could be a favorable method for production of complicated parts in macro and micro sizes. In this paper piezoelectric actuator is used as a novel approach in the field of micro manufacturing. Also, in current work, investigations are conducted with four rectangular punches and blanks with various thicknesses. Blank holder pressure effects on thickness distributions, punch force, and springback are studied. According to the results of this work, increasing of blank holder pressure in scaled deep drawing, in contrast to thickness of drawn part, leads to decrease in the punch forces and springback. Furthermore, it is shown that in micro deep drawing, the effects of holder pressure on mentioned parameters can be ignored.

  6. The Value of Agricultural Voucher Specimens

    OpenAIRE

    Barkworth,Mary; Wolf, Paul; Kinosian,Sylvia; Dyreson, Curtis; Pearse, Will; Brandt, Ben; Cobb,Neil

    2017-01-01

    Voucher specimens are the ultimate raw data of biodiversity studies because they document the interpretation of the names used in papers and reports resulting from such studies. The value of voucher specimens is increased by making their records web-accessible but they can be further enhanced by linking them to other online resources, particularly if the links are birectional.  In this presentation, we discuss the potential benefits of such links for a group of agricultural significance, the ...

  7. A study of the micro- and nanoscale deformation behavior of individual austenitic dendrites in a FeCrMoVC cast alloy using micro- and nanoindentation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Zeisig, J., E-mail: j.zeisig@ifw-dresden.de; Hufenbach, J.; Wendrock, H.; Gemming, T.; Kühn, U. [Leibniz Institute for Solid State and Materials Research, Institute for Complex Materials, P.O. Box 27 01 16, D-01171 Dresden (Germany); Eckert, J. [Leibniz Institute for Solid State and Materials Research, Institute for Complex Materials, P.O. Box 27 01 16, D-01171 Dresden (Germany); TU Dresden, Institute of Materials Science, Helmholtzstraße 7, D-01069 Dresden (Germany)

    2016-04-04

    Micro- and nanoindentation experiments were conducted to investigate the deformation mechanisms in a Fe79.4Cr13Mo5V1C1.6 (wt. %) cast alloy. This alloy consists of an as cast microstructure mainly composed of austenite, martensite, and a complex carbide network. During microhardness testing, metastable austenite transforms partially into martensite confirmed by electron backscatter diffraction. For nanoindentation tests, two different indenter geometries were applied (Berkovich and cube corner type). Load-displacement curves of nanoindentation in austenitic dendrites depicted pop-ins after transition into plastic deformation for both nanoindenters. Characterizations of the region beneath a nanoindent by transmission electron microscopy revealed a martensitic transformation as an activated deformation mechanism and suggest a correlation with the pop-in phenomena of the load-displacement curves. Furthermore, due to an inhomogeneous chemical composition within the austenitic dendrites, more stabilized regions deform by mechanical twinning. This additional deformation mechanism was only observed for the cube corner indenter with the sharper geometry since higher shear stresses are induced beneath the contact area.

  8. Moving Object Detection Using Scanning Camera on a High-Precision Intelligent Holder

    Directory of Open Access Journals (Sweden)

    Shuoyang Chen

    2016-10-01

    Full Text Available During the process of moving object detection in an intelligent visual surveillance system, a scenario with complex background is sure to appear. The traditional methods, such as “frame difference” and “optical flow”, may not able to deal with the problem very well. In such scenarios, we use a modified algorithm to do the background modeling work. In this paper, we use edge detection to get an edge difference image just to enhance the ability of resistance illumination variation. Then we use a “multi-block temporal-analyzing LBP (Local Binary Pattern” algorithm to do the segmentation. In the end, a connected component is used to locate the object. We also produce a hardware platform, the core of which consists of the DSP (Digital Signal Processor and FPGA (Field Programmable Gate Array platforms and the high-precision intelligent holder.

  9. Preparation and characterization of porous titanium using space-holder technique

    Institute of Scientific and Technical Information of China (English)

    NIU Wenjuan; BAI Chenguang; QIU Guibao; WANG Qiang; WEN Liangying; CHEN Dengfu; DONG Lingyan

    2009-01-01

    Titanium-based porous materials can be used in structural applications and medical implants because of their excellent mechanical properties at elevated temperatures, good corrosion resistance and wonderful biocompatibility. However, most of the methods used to produce the po-rous metal can only give limited porosity and uncontrollable pore morphologies. In the present study, a newly developed method of powder metallurgy using the space-holder technique was used to fabricate porous titanium with controllable porosity. The morphological features and mechanical properties of the products were fully investigated. The results show that the porosity is in the range of 55%-75%, and the mean pore size, with an average sphericity of~0.72, is 600 μm The plateau stresses vary between 10 MPa and 35 MPa. As predicted by the Gibson-Ashby model, the plateau stress decreases with increasing porosity.

  10. Holder continuity of bounded weak solutions to generalized parabolic p-Laplacian equations II: singular case

    Directory of Open Access Journals (Sweden)

    Sukjung Hwang

    2015-11-01

    Full Text Available Here we generalize quasilinear parabolic p-Laplacian type equations to obtain the prototype equation $$ u_t - \\hbox{div} \\Big(\\frac{g(|Du|}{|Du|} Du\\Big = 0, $$ where g is a nonnegative, increasing, and continuous function trapped in between two power functions $|Du|^{g_0 -1}$ and $|Du|^{g_1 -1}$ with $1Holder continuous with some degree of commonality between degenerate and singular types. By using geometric characters, our proof does not rely on any of alternatives which is based on the size of solutions.

  11. Measured Thermal and Fast Neutron Fluence Rates for ATF-1 Holders During ATR Cycle 157D

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Larry Don [Idaho National Lab. (INL), Idaho Falls, ID (United States); Miller, David Torbet [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-03-01

    This report contains the thermal (2200 m/s) and fast (E>1MeV) neutron fluence rate data for the ATF-1 holders located in core for ATR Cycle 157D which were measured by the Radiation Measurements Laboratory (RML) as requested by the Power Reactor Programs (ATR Experiments) Radiation Measurements Work Order. This report contains measurements of the fluence rates corresponding to the particular elevations relative to the 80-ft. core elevation. The data in this report consist of (1) a table of the ATR power history and distribution, (2) a hard copy listing of all thermal and fast neutron fluence rates, and (3) plots of both the thermal and fast neutron fluence rates. The fluence rates reported are for the average power levels given in the table of power history and distribution.

  12. 37 CFR 2.56 - Specimens.

    Science.gov (United States)

    2010-07-01

    ... indicate membership in the collective organization. (5) A certification mark specimen must show how a... of a union or other organization performed the work or labor on the goods or services. (c) A... be a digitized image in .jpg or .pdf format....

  13. Rehydration of forensically important larval Diptera specimens.

    Science.gov (United States)

    Sanford, Michelle R; Pechal, Jennifer L; Tomberlin, Jeffery K

    2011-01-01

    Established procedures for collecting and preserving evidence are essential for all forensic disciplines to be accepted in court and by the forensic community at large. Entomological evidence, such as Diptera larvae, are primarily preserved in ethanol, which can evaporate over time, resulting in the dehydration of specimens. In this study, methods used for rehydrating specimens were compared. The changes in larval specimens with respect to larval length and weight for three forensically important blow fly (Diptera: Calliphoridae) species in North America were quantified. Phormia regina (Meigen), Cochliomyia macellaria (F.), and Chrysomya rufifacies (Macquart) third-instar larvae were collected from various decomposing animals and preserved with three preservation methods (80% ethanol, 70% isopropyl alcohol, and hot-water kill then 80% ethanol). Preservative solutions were allowed to evaporate. Rehydration was attempted with either of the following: 80% ethanol, commercial trisodium phosphate substitute solution, or 0.5% trisodium phosphate solution. All three methods partially restored weight and length of specimens recorded before preservation. Analysis of variance results indicated that effects of preservation, rehydration treatment, and collection animal were different in each species. The interaction between preservative method and rehydration treatment had a significant effect on both P. regina and C. macellaria larval length and weight. In addition, there was a significant interaction effect of collection animal on larval C. macellaria measurements. No significant effect was observed in C. rufifacies larval length or weight among the preservatives or treatments. These methods could be used to establish a standard operating procedure for dealing with dehydrated larval specimens in forensic investigations.

  14. 17 CFR 270.32a-2 - Exemption for initial period from vote of security holders on independent public accountant for...

    Science.gov (United States)

    2010-04-01

    ... from vote of security holders on independent public accountant for certain registered separate accounts... from vote of security holders on independent public accountant for certain registered separate accounts... 32(a) of the Act that selection of an independent public accountant shall have been submitted...

  15. 26 CFR 1.860E-1 - Treatment of taxable income of a residual interest holder in excess of daily accruals.

    Science.gov (United States)

    2010-04-01

    ... short-term rate prescribed by section 1274(d) for the month of the transfer and the compounding period... interest holder in excess of daily accruals. 1.860E-1 Section 1.860E-1 Internal Revenue INTERNAL REVENUE... Trusts § 1.860E-1 Treatment of taxable income of a residual interest holder in excess of daily accruals...

  16. Power Holders and Social Dynamics of Participatory Development and Reconstruction: Cases from the Democratic Republic of Congo

    NARCIS (Netherlands)

    Kyamusugulwa, P.M.; Hilhorst, D.

    2015-01-01

    One of the challenges of participatory development and reconstruction programs is how and where to engage with power holders. This paper analyses the dynamics of power relations within a community-driven reconstruction program in the Democratic Republic of Congo. It shows that, in some circumstances

  17. Determinants of Increasing Duration of First Unemployment among First Degree Holders in Rwanda: A Logistic Regression Analysis

    Science.gov (United States)

    Niragire, François; Nshimyiryo, Alphonse

    2017-01-01

    Unexpectedly, the duration of first unemployment among first degree holders has quickly increased in Rwanda after considerable loss of the skilled labour during the war and Genocide perpetrated against Tutsi in 1994. The time it takes a higher education graduate to land a first employment is a key indicator for the evaluation of and optimal…

  18. 14 CFR 193.17 - How must design and production approval holders handle information they receive from the FAA...

    Science.gov (United States)

    2010-01-01

    ... REGULATIONS PROTECTION OF VOLUNTARILY SUBMITTED INFORMATION § 193.17 How must design and production approval... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false How must design and production approval holders handle information they receive from the FAA under this part? 193.17 Section 193.17...

  19. 76 FR 22912 - Notice of Cancellation of Customs Broker Licenses Due to Death of the License Holder

    Science.gov (United States)

    2011-04-25

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY U.S. Customs and Border Protection Notice of Cancellation of Customs Broker Licenses Due to Death of the License Holder AGENCY: U.S. Customs and Border Protection, DHS. ACTION: General...

  20. 76 FR 44033 - Notice of Cancellation of Customs Broker Licenses Due to Death of the License Holder

    Science.gov (United States)

    2011-07-22

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY U.S. Customs and Border Protection Notice of Cancellation of Customs Broker Licenses Due to Death of the License Holder AGENCY: U.S. Customs and Border Protection, U.S. Department of...

  1. 75 FR 11899 - Notice of Cancellation of Customs Broker Licenses Due to Death of the License Holder

    Science.gov (United States)

    2010-03-12

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY Customs and Border Protection Notice of Cancellation of Customs Broker Licenses Due to Death of the License Holder AGENCY: U.S. Customs and Border Protection, U.S. Department of Homeland...

  2. 77 FR 45648 - Notice of Cancellation of Customs Broker Licenses Due to Death of the License Holder

    Science.gov (United States)

    2012-08-01

    ... [Federal Register Volume 77, Number 148 (Wednesday, August 1, 2012)] [Notices] [Page 45648] [FR Doc No: 2012-18740] DEPARTMENT OF HOMELAND SECURITY U.S. Customs and Border Protection Notice of Cancellation of Customs Broker Licenses Due to Death of the License Holder AGENCY: U.S. Customs and...

  3. 77 FR 16249 - Notice of Cancellation of Customs Broker Licenses Due to Death of the License Holder

    Science.gov (United States)

    2012-03-20

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY U.S. Customs and Border Protection Notice of Cancellation of Customs Broker Licenses Due to Death of the License Holder AGENCY: U.S. Customs and Border Protection, U.S. Department of...

  4. 76 FR 2918 - Notice of Cancellation of Customs Broker Licenses Due to Death of the License Holder

    Science.gov (United States)

    2011-01-18

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY U.S. Customs and Border Protection Notice of Cancellation of Customs Broker Licenses Due to Death of the License Holder AGENCY: U.S. Customs and Border Protection, U.S. Department of...

  5. Measured thermal and fast neutron fluence rates for ATF-1 holders during ATR cycle 158B/159A

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Larry Don [Idaho National Lab. (INL), Idaho Falls, ID (United States); Miller, David Torbet [Idaho National Lab. (INL), Idaho Falls, ID (United States); Walker, Billy Justin [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-11-01

    This report contains the thermal (2200 m/s) and fast (E>1MeV) neutron fluence rate data for the ATF-1 holders located in core for ATR Cycle 158B/159A which were measured by the Radiation Measurements Laboratory (RML).

  6. 26 CFR 301.6323(a)-1 - Purchasers, holders of security interests, mechanic's lienors, and judgment lien creditors.

    Science.gov (United States)

    2010-04-01

    ..., mechanic's lienors, and judgment lien creditors. 301.6323(a)-1 Section 301.6323(a)-1 Internal Revenue... ADMINISTRATION Collection General Provisions § 301.6323(a)-1 Purchasers, holders of security interests, mechanic... of a security interest (as defined in paragraph (a) of § 301.6323(h)—1), mechanic's lienor...

  7. Operation of blast furnace gas (BFG) gas holder with ld gas (LDG); Operacao do gasometro de gas de alto forno com gas de aciaria

    Energy Technology Data Exchange (ETDEWEB)

    Sampaio, William Genelhu; Valentino, Waldir Smith [Usinas Siderurgicas de Minas Gerais S/A (USIMINAS), Ipatinga, MG (Brazil)

    2010-07-01

    The Intendente Camara plant, one of USIMINAS steel works, located in Ipatinga - MG, operates its network of process gases with two Coke-Oven Gas (COG) oil-seal gas holders, one Blast Furnace Gas (BFG) oil-seal gas holder and a LD gas (LDG) telescope type gas holder. During the repair of LDG gas holder, this gas would be completely burned in the flares for a period of five months. Due to this loss, the cost of additional fuel and interventions in the production rhythm of the Hot Strip Mill, its biggest consumer, would be high. This paper presents the philosophy and pillars that mitigated these losses, highlighting how it was possible to operate the BFG gas holder with LDG, the achieved economy and lessons learned from the process. (author)

  8. Nanomechanical measurements of hair as an example of micro-fibre analysis using atomic force microscopy nanoindentation.

    Science.gov (United States)

    Clifford, Charles A; Sano, Naoko; Doyle, Peter; Seah, Martin P

    2012-03-01

    The characterisation of nanoscale surface properties of textile and hair fibres is key to developing new effective laundry and hair care products. Here, we develop nanomechanical methods to characterise fibres using an atomic force microscope (AFM) to give their nanoscale modulus. Good mounting methods for the fibre that are chemically inert, clean and give strong mechanical coupling to a substrate are important and here we detail two methods to do this. We show, for elastic nanoindentation measurements, the situation when the tip radius significantly affects the result via a function of the ratio of the radii of the tip and fibre and indicate the importance of using an AFM for such work. A valid method to measure the nanoscale modulus of fibres using AFM is thus detailed and exampled on hair to show that bleaching changes the nanoscale reduced modulus at the outer surface. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

  9. Thermally Activated Deformation Behavior of ufg-Au: Environmental Issues During Long-Term and High-Temperature Nanoindentation Testing

    Science.gov (United States)

    Maier, Verena; Leitner, Alexander; Pippan, Reinhard; Kiener, Daniel

    2015-12-01

    For testing time-dependent material properties by nanoindentation, in particular for long-term creep or relaxation experiments, thermal drift influences on the displacement signal are of prime concern. To address this at room and elevated temperatures, we tested fused quartz at various contact depths at room temperature and ultra-fine grained (ufg) Au at various temperatures. We found that the raw data for fused quartz are strongly affected by thermal drift, but corrected by use of dynamic stiffness measurements all the datasets collapse. The situation for the ufg Au shows again that the data are only useful with drift correction, but with this applied it turns out that there is a significant change of elastic and plastic properties when exceeding 200°C, which is also reflected by an increasing strain rate sensitivity.

  10. High creep strain rates observed in nanocrystalline α-Fe{sub 2}O{sub 3} particles by nanoindentation measurement

    Energy Technology Data Exchange (ETDEWEB)

    Hajra, P.; Saha, D.R. [MLS Professor' s Unit, Indian Association for the Cultivation of Science, 2A and 2B Raja S.C. Mullick Road, Kolkata 700032 (India); Mada, M.R. [School of Materials Science and Engineering, Kensington, University of New South Wales, Sydney 2052 (Australia); Dutta, S. [Department of Physics, Rammohan College, 102/1 Raja Rammohan Roy Sarani, Kolkata 700009 (India); Brahma, P. [Department of Physics, Gurudas College, Kolkata 700054 (India); Boughton, P.; Bandyopadhyay, S. [School of Materials Science and Engineering, Kensington, University of New South Wales, Sydney 2052 (Australia); Chakravorty, D., E-mail: mlsdc@iacs.res.in [MLS Professor' s Unit, Indian Association for the Cultivation of Science, 2A and 2B Raja S.C. Mullick Road, Kolkata 700032 (India)

    2014-05-01

    Nanocrystalline α-Fe{sub 2}O{sub 3} with particle sizes in the range 10–24 nm were produced by mechanical milling of micron-sized α-Fe{sub 2}O{sub 3} particles. Microstructures of sintered pellets of cold compacted powder were investigated by electron microscopy. Nanoindentation studies showed the creep strain rates had values of the order of 10{sup −4} s{sup −1} at room temperature with creep increasing to higher values with increase of particle diameter. This was attributed to grain boundary sliding enhancement due to a piezomagnetic-type effect in the particles. Compressive tests at room temperature carried out on bulk samples with nanosized crystallites also showed large creep strain rate behaviour. The result will be helpful in designing ceramic systems with plastic behaviour at room temperature.

  11. Young's modulus measurements of SiC coatings on spherical particles by using nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Tan, J.; Meadows, P.J. [School of Materials, University of Manchester, Manchester, M1 7HS (United Kingdom); Zhang, D. [School of Mechanical, Aerospace and Civil Engineering, University of Manchester (United Kingdom); Chen Xi [Department of Civil Engineering and Engineering Mechanics, Columbia University, New York (United States); Lopez-Honorato, E.; Zhao, X.; Yang, F. [School of Materials, University of Manchester, Manchester, M1 7HS (United Kingdom); Abram, T. [School of Mechanical, Aerospace and Civil Engineering, University of Manchester (United Kingdom); Xiao, P., E-mail: ping.xiao@manchester.ac.u [School of Materials, University of Manchester, Manchester, M1 7HS (United Kingdom)

    2009-08-15

    Spherical silicon carbide coatings are deposited by fluidised bed chemical vapour deposition for the application to Tristructural Isotropic (TRISO) coated fuel particles. The silicon carbide exhibits columnar structure and grows along the radial direction during deposition. In this work, two measurements are made with nanoindentation, one is measured vertically to the grain growth direction, which gives a Young's modulus of 391.1 +- 12.9 GPa, and the other is measured along the grain growth direction which gives a Young's modulus of 442.5 +- 13.3 GPa. Finite element analysis and a theoretical effort are introduced to estimate the bending contribution when the indentation is carried out on the external surface of SiC. The relationship between grain orientation of SiC and its Young's modulus has been examined.

  12. Characterization of Impact Damage in Ultra-High Performance Concrete Using Spatially Correlated Nanoindentation/SEM/EDX

    Science.gov (United States)

    Moser, R. D.; Allison, P. G.; Chandler, M. Q.

    2013-12-01

    Little work has been done to study the fundamental material behaviors and failure mechanisms of cement-based materials including ordinary Portland cement concrete and ultra-high performance concretes (UHPCs) under high strain impact and penetration loads at lower length scales. These high strain rate loadings have many possible effects on UHPCs at the microscale and nanoscale, including alterations in the hydration state and bonding present in phases such as calcium silicate hydrate, in addition to fracture and debonding. In this work, the possible chemical and physical changes in UHPCs subjected to high strain rate impact and penetration loads were investigated using a novel technique wherein nanoindentation measurements were spatially correlated with images using scanning electron microscopy and chemical composition using energy dispersive x-ray microanalysis. Results indicate that impact degrades both the elastic modulus and indentation hardness of UHPCs, and in particular hydrated phases, with damage likely occurring due to microfracturing and debonding.

  13. Simulation and Experiment on Surface Morphology and Mechanical Properties Response in Nano-Indentation of 6H-SiC

    Science.gov (United States)

    Li, Chen; Zhang, Feihu; Meng, Binbin; Ma, Zhaokai

    2017-02-01

    The nano-indentation test for 6H-SiC is carried out with a Berkovich indenter. The indentation surface morphology is analyzed by SEM, which show that when the maximum load P max is 8 mN, there is only plastic deformation and no cracks on the surface of workpiece after unloading process, and when P max is 10 mN, there is the initiation of crack occurring on the surface of workpiece after unloading process. Based on the strain hardening model, the three-dimensional finite element method of nano-indentation for 6H-SiC is carried out. Simulation results show that in the unloading process the maximum stress and the maximum strain occur in the contact area between the workpiece with the indenter edges, which is consistent with the experimental results. When propagate to the surface from the subsurface, the cracks are subjected to the type I stress and the type II stress due to elastic recovery. After propagating to surface of workpiece, the cracks propagate along a fixed direction because the proportion of type I stress is much larger than that of type II stress. The influence of the cleavage plane on the propagation direction of cracks is obvious. The cracks propagate more easily when the indenter edges are along cleavage plane. The indentation depth and residual depth increase with the increase of P max. While, the elastic recovery rate gradually decreases and tends to be stable with the increase of P max. When P max is <10 mN, the micro-hardness and the elastic modulus increase linearly with the increase of P max. When P max exceeds 10 mN, the micro-hardness decreases with the increase of P max and then gradually tends to be stable, and the elastic modulus increases by power function with the increase of P max and then gradually tends to be stable.

  14. Tuning heterogeneous poly(dopamine) structures and mechanics: in silico covalent cross-linking and thin film nanoindentation.

    Science.gov (United States)

    Lin, Shangchao; Chen, Chun-Teh; Bdikin, Igor; Ball, Vincent; Grácio, José; Buehler, Markus J

    2014-01-21

    Mussel-inspired synthetic poly(dopamine) thin films from dihydroxyphenylalanine (DOPA) and lysine, structurally similar to natural melanin, have drawn extensive interest as a versatile surface functionalization and coating material for use in a broad range of applications. In order to gain a better understanding of its complex and heterogeneous polymeric structure and mechanical properties, we report a computational model of poly(dopamine) by mimicking the polymerization process of the intermediate oxidized product of dopamine, 5,6-dihydroxyindole (DHI), via controlled in silico covalent cross-linking under the two most possible reaction schemes proposed in experiments. To validate our results using experiment, we synthesize poly(dopamine) thin films and perform experimental nanoindentations on the film. We observe an overall linear behavior for Young's modulus as a function of the degree of cross-linking, demonstrating the possibility of enhancing the mechanical robustness of poly(dopamine) materials by increasing the extent of polymerization. At the highest degree of polymerization considered (70%), the model mimics the linear tetrameric model for poly(dopamine) and melanin. At this degree of polymerization, we find a Young's modulus of 4.1-4.4 GPa, in agreement with our nanoindentation results of 4.3-10.5 GPa, previous experiments for natural melanin, as well as simulation results for the cyclic tetrameric melanin model (Chen et al., ACS Nano, 2013). Our results suggest that the non-covalent DHI aggregate model might not be appropriate to represent the structure of poly(dopamine) and melanin-like materials, since it gives a much smaller Young's modulus than the experimental lower bound. Our model not only nicely complements the previous computational work, but also provides new computational tools to study the heterogeneous structural and physicochemical properties of poly(dopamine) and melanin, as well as their formation pathways.

  15. Breast specimen shrinkage following formalin fixation

    Directory of Open Access Journals (Sweden)

    Horn CL

    2014-02-01

    Full Text Available Christopher L Horn, Christopher Naugler Department of Pathology and Laboratory Medicine, University of Calgary, and Calgary Laboratory Services, Calgary, AB, Canada Abstract: Accurate measurement of primary breast tumors and subsequent surgical margin assessment is critical for pathology reporting and resulting patient therapy. Anecdotal observations from pathology laboratory staff indicate possible shrinkage of breast cancer specimens due to the formalin fixation process. As a result, we conducted a prospective study to investigate the possible shrinkage effects of formalin fixation on breast cancer specimens. The results revealed no significant changes in tumor size, but there were significant changes in the distance to all surgical resection margins from the unfixed to fixed state. This shrinkage effect could interfere with the accuracy of determining distance to margin assessment and tumor-free margin assessment. Thus, changes in these measurements due to the formalin fixation process have the potential to alter treatment options for the patient. Keywords: breast margins, formalin, shrinkage, cancer

  16. Is routine histopathology of tonsil specimen necessary?

    Directory of Open Access Journals (Sweden)

    Agida S Adoga

    2011-01-01

    Full Text Available Background: Tonsillar diseases are common in paediatric and adult otolaryngological practice. These diseases require tonsillectomy. Specimens are subjected to histopathology routinely in my institution for fear of infections and tumour without consideration for risk factors. The financial burden is on the patients and waste of histopathologist′s man hour because other specimens are left un-attended. This study aims to find out the necessity of routine histopathology of tonsil specimens. Materials and Methods : A 2 year retrospective review of the histopathological results of two (paediatric and adult groups of 61 patients managed for tonsillar diseases at the ENT UNIT of Jos University Teaching Hospital from July 2005 to June, 2007. Data extracted included biodata, clinical features and histopathological diagnosis. Result : The 61 patients comprise 35 children and 26 adults. The youngest and oldest paediatric patients were 1 year and 3 months and 16 years respectively, a range of 1 year 3 months to 16 years. The youngest and oldest adults were 17 and 50 years with a range of 17-50 years. Groups mean ages were 5.1 and 28.5 years. The gender ratios were 1:2.7 and 1:1.9 respectively. One adult was HIV positive. The histopathological diagnosis were chronic nonspecific tonsillitis in 10(16.6%, follicular tonsillitis in 23(38.3%, chronic suppurative tonsillitis in 10(16.6%, lymphoid hyperplasia in 18(30.0% and lymphoma in 1(1.0% respectively. Conclusion : Histopathologic request for tonsillectomy specimens should be based on certain risk factors with consideration of the cost to patients and to spare the histopathologist′s man hour.

  17. SQA specimen paper 2013, national 5, French

    CERN Document Server

    SQA

    2013-01-01

    Practise for your exam on the offical National 5 specimen paper from the Scottish Qualifications Authority. Plus each book includes additional model papers and extra revision guidance, making them an essential purchase for any student.; Discover how to get your best grade with answers checked by senior examiners.; Prepare for your exams with study skills guidance sections.; Gain vital extra marks and avoid common mistakes with examiner tips

  18. Damage modeling in Small Punch Test specimens

    DEFF Research Database (Denmark)

    Martínez Pañeda, Emilio; Cuesta, I.I.; Peñuelas, I.

    2016-01-01

    Ductile damage modeling within the Small Punch Test (SPT) is extensively investigated. The capabilities ofthe SPT to reliably estimate fracture and damage properties are thoroughly discussed and emphasis isplaced on the use of notched specimens. First, different notch profiles are analyzed...... and constraint conditionsquantified. The role of the notch shape is comprehensively examined from both triaxiality and notchfabrication perspectives. Afterwards, a methodology is presented to extract the micromechanical-basedductile damage parameters from the load-displacement curve of notched SPT samples...

  19. Incidental prostate cancer in radical cystoprostatectomy specimens

    Institute of Scientific and Technical Information of China (English)

    Xiao-Dong Jin; Zhao-Dian Chen; Bo Wang; Song-Liang Cai; Xiao-Lin Yao; Bai-Ye Jin

    2008-01-01

    Aim: To investigate the rates of prostate cancer (Pca) in radical cystoprostatectomy (RCP) specimens for bladder cancer in mainland China. To determine the follow-up outcome of patients with two concurrent cancers and identify whether prostate-specific antigen (PSA) is a useful tool for the detection of Pca prior to surgery. Methods: From January 2002 to January 2007, 264 male patients with bladder cancer underwent RCP at our center. All patients underwent digital rectal examination (DRE) and B ultrasound. Serum PSA levels were tested in 168 patients. None of the patients had any evidence of Pca before RCP. Entire prostates were embedded and sectioned at 5 mm intervals. Results: Incidental Pca was observed in 37 of 264 (14.0%) RCP specimens. Of these, 12 (32.4%) were clinically significant according to an accepted definition. The PSA levels were not significantly different between patients with Pca and those without Pca, nor between patients with significant Pca and those with insignificant Pca. Thirty-four patients with incidental Pca were followed up. During a mean follow-up period of 26 months, two patients with PSA > 4 ng/mL underwent castration. None of the patients died of Pca. Conclusion: The incidence of Pca in RCP specimens in mainland China is lower than that in most developed countries. PSA cannot identify asymptomatic Pca prior to RCP. In line with published reports, incidental Pca does not impact the prognosis of bladder cancer patients undergoing RCP.

  20. 42 CFR 493.1232 - Standard: Specimen identification and integrity.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 5 2010-10-01 2010-10-01 false Standard: Specimen identification and integrity... Nonwaived Testing General Laboratory Systems § 493.1232 Standard: Specimen identification and integrity. The... optimum integrity of a patient's specimen from the time of collection or receipt of the specimen through...

  1. HMSRP Hawaiian Monk Seal Specimen Data (includes physical specimens, collection information, status, storage locations, and laboratory results associated with individual specimens)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set includes physical specimens, paper logs and Freezerworks database of all logged information on specimens collected from Hawaiian monk seals since 1975....

  2. Nanoscale analysis of unstained biological specimens in water without radiation damage using high-resolution frequency transmission electric-field system based on FE-SEM.

    Science.gov (United States)

    Ogura, Toshihiko

    2015-04-10

    Scanning electron microscopy (SEM) has been widely used to examine biological specimens of bacteria, viruses and proteins. Until now, atmospheric and/or wet biological specimens have been examined using various atmospheric holders or special equipment involving SEM. Unfortunately, they undergo heavy radiation damage by the direct electron beam. In addition, images of unstained biological samples in water yield poor contrast. We recently developed a new analytical technology involving a frequency transmission electric-field (FTE) method based on thermionic SEM. This method is suitable for high-contrast imaging of unstained biological specimens. Our aim was to optimise the method. Here we describe a high-resolution FTE system based on field-emission SEM; it allows for imaging and nanoscale examination of various biological specimens in water without radiation damage. The spatial resolution is 8 nm, which is higher than 41 nm of the existing FTE system. Our new method can be easily utilised for examination of unstained biological specimens including bacteria, viruses and protein complexes. Furthermore, our high-resolution FTE system can be used for diverse liquid samples across a broad range of scientific fields, e.g. nanoparticles, nanotubes and organic and catalytic materials.

  3. Development of a nanoindenter for in-situ transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Stach, Eric A.; Freeman, Tony; Minor, Andrew M.; Owen, Doug K.; Cumings, John; Wall, Mark A.; Chraska, Tomas; Hull, Robert; Morris Jr., J.W.; Zettl, A.; Dahmen, Ulrich

    2001-01-30

    In-situ transmission electron microscopy is an established experimental technique that permits direct observation of the dynamics and mechanisms of dislocation motion and deformation behavior. In this paper, we detail the development of a novel specimen goniometer that allows real time observations of the mechanical response of materials to indentation loads. The technology of the scanning tunneling microscope is adopted to allow nanometer scale positioning of a sharp, conductive diamond tip onto the edge of an electron transparent sample. This allows application of loads to nanometer-scale material volumes couple with simultaneous imaging of the material response. The emphasis in this paper is experimental and descriptive, with particular attention given to sample geometry and other technical requirements. Examples of the deformation of aluminum and titanium carbide as well as the fracture of silicon will be presented.

  4. The nanoindentation applied to predict the interface delamination for the C/amorphous Si composite film

    Science.gov (United States)

    Han, Chang-Fu; Huang, Chao-Yu; Wu, Bo-Hsiung; Lin, Jen-Fin

    2009-10-01

    In the present study, the indentation depth corresponding to the pop-in arising in the loading process is found to be quite close to the C/amorphous Si composite film thickness, regardless of the C-film thickness. This load-depth behavior gives a clue that the occurrence of pop-in is perhaps related to the buckling of the composite film, which had already delaminated from the silicon substrate. This indentation depth of buckling predicted by the present model is quite close to the pop-in depth obtained from experimental results, regardless of the change in the C-film thickness. This characteristic reveals that the present model is developed successfully to predict the pop-in depth of a specimen, and the pop-in is indeed created due to the buckling of the composite film under a compression stress.

  5. Seroprevalences of vector-transmitted infections of small-holder dairy cattle in coastal Kenya.

    Science.gov (United States)

    Maloo, S H; Thorpe, W; Kioo, G; Ngumi, P; Rowlands, G J; Perry, B D

    2001-11-02

    A cross-sectional study was carried out from July to September 1989 in Kaloleni Division, Coast Province, Kenya to estimate the prevalence of vector-transmitted diseases in small-holder dairy cattle and to identify the risk factors associated with different management systems. One hundred and thirty of the 157 herds with dairy cattle in Kaloleni Division were surveyed. These were from three agro-ecological zones (coconut-cassava, cashew nut-cassava and livestock-millet), comprised two management systems (stall-feeding and herded grazing) and were herds with either dairy cattle only or with Zebu and dairy cattle. A formal questionnaire sought answers to questions on cattle health and management practices. A total of 734 dairy and 205 Zebu cattle in 78 dairy and 52 mixed (dairy and Zebu) herds were sampled and screened for haemoparasites (Trypanosoma, Anaplasma, Babesia, and Theileria infections). Sera were tested for antibodies to Theileria parva, using the schizonts-antigen indirect fluorescent-antibody (IFA) test and to antibodies for Babesia bigemina and antigens to Anaplasma marginale by enzyme-linked immunosorbent assay (ELISA). Packed-cell volume (PCV) also was measured. Tick-control measures were practised by all except three of the farmers. Despite this, overall seroprevalence to T. parva was >70%--suggesting either that control practices were not strictly implemented or they were ineffective. The seroprevalence of T. parva in adult cattle kept in stall-feeding systems in the coconut-cassava zone was significantly lower (57+/-8% (S.E.)) than in herded-grazing systems (79+/-3%) and there was no association between antibody prevalence and age of cattle in this zone. Antibody prevalences in cattle in the cashew nut-cassava and the drier livestock-millet zone increased with age. Cattle in herded-grazing systems had an overall lower seroprevalence of T. parva infection in the livestock-millet zone (45+/-6%) than in the other two zones. Analysis was confined to

  6. Wildlife specimen collection, preservation, and shipment

    Science.gov (United States)

    White, C. LeAnn; Dusek, Robert J.; Franson, J. Christian; Friend, Milton; Gibbs, Samantha E.J.; Wild, Margaret A.

    2015-01-01

    Specimens are used to provide supporting information leading to the determination of the cause of disease or death in wildlife and for disease monitoring or surveillance. Commonly used specimens for wildlife disease investigations include intact carcasses, tissues from carcasses, euthanized or moribund animals, parasites, ingested food, feces, or environmental samples. Samples from live animals or the environment (e.g., contaminated feed) in the same vicinity as a mortality event also may be helpful. The type of specimen collected is determined by availability of samples and biological objectives. Multiple fresh, intact carcasses from affected species are the most useful in establishing a cause for a mortality event. Submission of entire carcasses allows observation of gross lesions and abnormalities, as well as disease testing of multiple tissues. Samples from live animals may be more appropriate when sick animals cannot be euthanized (e.g., threatened or endangered species) or for research and monitoring projects examining disease or agents circulating in apparently healthy animals or those not exhibiting clinical signs. Samples from live animals may include collections of blood, hair, feathers, feces, or ectoparasites, or samples obtained by swabbing lesions or orifices. Photographs and videos are useful additions for recording field and clinical signs and conveying conditions at the site. Collection of environmental samples (e.g., feces, water, feed, or soil) may be appropriate when animals cannot be captured for sampling or the disease agent may persist in the environment. If lethal collection is considered necessary, biologists should refer to the policies, procedures, and permit requirements of their institution/facility and the agency responsible for species management (U.S. Fish and Wildlife Service or State natural resource agency) prior to use in the field. If threatened or endangered species are found dead, or there is evidence of illegal take, field

  7. Histological evaluation of 400 cholecystectomy specimens

    Directory of Open Access Journals (Sweden)

    H Kumar

    2015-09-01

    Full Text Available Background: A majority of gallbladder specimens show changes associated with chronic cholecystitis; however few harbour a highly lethal carcinoma. This study was conducted to review the significant histopathological findings encountered in gallbladder specimens received in our laboratory.Materials and Methods: Four hundred cholecystectomy specimens were studied over a period of five years (May, 2002 to April, 2007 received at department of pathology, Kasturba Medical College, Mangalore, India. Results: Gallstones and associated diseases were more common in women in the 4th to 5th decade as compared to men with M: F ratio of 1:1.33. Maximum number of patients (28.25% being 41 to 50 years old. Histopathologically, the most common diagnosis was chronic cholecystitis (66.75%, followed by chronic active cholecystitis (20.25%, acute cholecystitis (6%, gangrenous cholecystitis (2.25%,xanthogranulomatous cholecystitis (0.50%, empyema (1%, mucocele (0.25%, choledochal cyst (0.25%, adenocarcinoma gallbladder (1.25% and  normal  gallbladders (1%.Conclusion: All lesions were found more frequently in women except chronic active cholecystitis. Gallstones were present in (80.25% cases, and significantly associated with various lesions (P value 0.009. Pigment stones were most common, followed by cholesterol stones and mixed stones. Adequate  sectioning  is  mandatory  in  all  cases  to  assess  epithelial changes arising from cholelithiasis and chronic cholecystitis as it has been known to progress to malignancy in some cases.

  8. Isolation of Klebsiella terrigena from clinical specimens.

    Science.gov (United States)

    Podschun, R; Ullmann, U

    1992-04-01

    In a three-year survey conducted from 1988 to 1990 Klebsiella isolates from human clinical specimens were subjected to additional tests to identify any Klebsiella terrigena strains. Ten strains of Klebsiella terrigena (0.4%) were found among 2355 indole-negative Klebsiella isolates. Most of the isolates were recovered from the respiratory tract. In the API20EC system almost exclusively biotypes no. 1777771 and 1777671 were observed. Serotyping revealed capsule types K2, K5 and K18 in two strains each. In antibiotic susceptibility tests the strains were shown to be comparable in sensitivity to Klebsiella pneumoniae.

  9. The effect of simulated flash heating pasteurisation and Holder pasteurisation on human milk oligosaccharides.

    Science.gov (United States)

    Daniels, Brodie; Coutsoudis, Anna; Autran, Chloe; Amundson Mansen, Kimberly; Israel-Ballard, Kiersten; Bode, Lars

    2017-08-01

    Human milk oligosaccharides (HMOs) have important protective functions in human milk. A low-cost remote pasteurisation temperature-monitoring system has been designed using FoneAstra, a cell phone-based networked sensing system to monitor simulated flash heat pasteurisation. To compare the pasteurisation effect on HMOs of the FoneAstra FH method with the current Sterifeed Holder method used by human milk banks. Donor human milk samples (n = 48) were obtained from a human milk bank and pasteurised using the two pasteurisation methods. HMOs were purified from samples and labelled before separation using high-performance liquid chromatography. Concentrations of total HMOs, sialylated and fucosylated HMOs and individual HMOs using the two pasteurisation methods were compared using repeated-measures ANOVA. The study demonstrated no difference in total concentration of HMOs between the two pasteurisation methods and a small but significant increase in the total concentration of HMOs regardless of pasteurisation methods compared with controls (unpasteurised samples) (pmilk and therefore is a possible alternative for providing safely sterilised human milk for low- and middle-income countries.

  10. Numerical simulation and experimental assessment for cold cylindrical deep drawing without blank-holder

    Science.gov (United States)

    Chiorescu, D.; Chiorescu, E.; Filipov, F.

    2016-08-01

    The metal forming process through plastic deformation, represented by deep drawing, is an extremely vast research field. In this article we analyse the influence of the die punch clearance, the average velocity in the active phase as well as of the lubrication on the deep drawing quality revealed by the thickness evenness on the finished product surface. For thorough research and in order to minimize the number of experimental trials, a fractional factorial design of TAGUCHI type was developed attached to an orthogonal array, thus analysing the contribution of the three aforementioned parameters to the quality of cylindrical deep drawing without a blank holder. In order to compare the experimental results, a conceptual 3D model of the system punch-blank-die was made, which respects entirely the geometry of the active elements and of the blank, but schematizes/approximates the material properties of the blank. Thus, using these simulations, we can investigate the variation of the deformation parameters throughout the drawing process: from the initial blank form to the final drawn part. The numerical simulation of the drawing of cylindrical cups was made using the ANSYS V14 program, the Explicit Dynamic module. Using the signal-to-noise ratio suggested by TAGUCHI, we determined the influence of each of the three parameters under study on deep drawing quality, as well as their optimal values.

  11. The training principles of the Greek record holder in the women’s hammer throw

    Directory of Open Access Journals (Sweden)

    THEOPHILOS PILIANIDIS

    2013-01-01

    Full Text Available The aim of this case study was to evaluate the long term training periodization of the Greek record holder in women’s hammer throw. The training parameters which were recorded and assessed in relation to the athlete' s best throwing performance were: the strength training, the running and jumping exercises, the specific throws with implements of various weights and the imitation drills. The evaluation of the athlete's longitudinal planning showed that after 5 years of intensive training the throwing performance of the athlete was maximized. In addition, the training seasons 2003-2005 of the studied athlete were characterized by the high volume of the biomotor elements of strength, speed and throwing skills. The assessment of the interaction between the training means and the throwing performance showed that the athlete's improvement was strongly related to the upper-body strength and the lower-body explosive power. Furthermore, the imitation drills and the specific throws with implements contributed to the athlete' s throwing development. In summary, this training report presents the performance progress of a world-class athlete emphasizing that the coach must be focused firstly on building-up the female thrower's strength and then to bridge the gap between the explosive power and technique.

  12. A (S)TEM Gas Cell Holder with Localized Laser Heating for In Situ Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Mehraeen, Shareghe [Univ. of California, Davis, CA (United States). Dept. of Molecular and Cellular Biology; McKeown, Joseph T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Condensed Matter and Materials Division; Deshmukh, Pushkarraj V. [E.A. Fischione Instruments, Inc., Export, PA (United States); Evans, James E. [Univ. of California, Davis, CA (United States). Dept. of Molecular and Cellular Biology; Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Chemical and Materials Science Division; Abellan, Patricia [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Chemical and Materials Science Division; Xu, Pinghong [Univ. of California, Davis, CA (United States). Dept. of Chemical Engineering and Materials Science; Reed, Bryan W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Condensed Matter and Materials Division; Taheri, Mitra L. [Drexel Univ., Philadelphia, PA (United States). Dept. of Materials Science & Engineering; Fischione, Paul E. [E.A. Fischione Instruments, Inc., Export, PA (United States); Browning, Nigel D. [Univ. of California, Davis, CA (United States). Dept. of Molecular and Cellular Biology; Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Chemical and Materials Science Division; Univ. of California, Davis, CA (United States). Dept. of Chemical Engineering and Materials Science

    2013-03-04

    We report that the advent of aberration correction for transmission electron microscopy has transformed atomic resolution imaging into a nearly routine technique for structural analysis. Now an emerging frontier in electron microscopy is the development of in situ capabilities to observe reactions at atomic resolution in real time and within realistic environments. Here we present a new in situ gas cell holder that is designed for compatibility with a wide variety of sample type (i.e., dimpled 3-mm discs, standard mesh grids, various types of focused ion beam lamellae attached to half grids). Its capabilities include localized heating and precise control of the gas pressure and composition while simultaneously allowing atomic resolution imaging at ambient pressure. The results show that 0.25-nm lattice fringes are directly visible for nanoparticles imaged at ambient pressure with gas path lengths up to 20 μm. Additionally, we quantitatively demonstrate that while the attainable contrast and resolution decrease with increasing pressure and gas path length, resolutions better than 0.2 nm should be accessible at ambient pressure with gas path lengths less than the 15 μm utilized for these experiments.

  13. Fatigue behavior of highly porous titanium produced by powder metallurgy with temporary space holders.

    Science.gov (United States)

    Özbilen, Sedat; Liebert, Daniela; Beck, Tilmann; Bram, Martin

    2016-03-01

    Porous titanium cylinders were produced with a constant amount of temporary space holder (70 vol.%). Different interstitial contents were achieved by varying the starting powders (HDH vs. gas atomized) and manufacturing method (cold compaction without organic binders vs. warm compaction of MIM feedstocks). Interstitial contents (O, C, and N) as a function of manufacturing were measured by chemical analysis. Samples contained 0.34-0.58 wt.% oxygen, which was found to have the greatest effect on mechanical properties. Quasi-static mechanical tests under compression at low strain rate were used for reference and to define parameters for cyclic compression tests. Not unexpectedly, increased oxygen content increased the yield strength of the porous titanium. Cyclic compression fatigue tests were conducted using sinusoidal loading in a servo-hydraulic testing machine. Increased oxygen content was concomitant with embrittlement of the titanium matrix, resulting in significant reduction of compression cycles before failure. For samples with 0.34 wt.% oxygen, R, σ(min) and σ(max) were varied systematically to estimate the fatigue limit (~4 million cycles). Microstructural changes induced by cyclic loading were then characterized by optical microscopy, SEM and EBSD.

  14. Shaft seals with an easily removable cylinder holder for low-pressure steam turbines

    Science.gov (United States)

    Zakharov, A. E.; Rodionov, D. A.; Pimenov, E. V.; Sobolev, A. S.

    2016-01-01

    The article is devoted to the problems that occur at the operation of LPC shaft seals (SS) of turbines, particularly, their bearings. The problems arising from the deterioration of oil-protecting rings of SS and bearings and also the consequences in which they can result are considered. The existing SS housing construction types are considered. Their operational features are specified. A new SS construction type with an easily removable holder is presented. The construction of its main elements is described. The sequence of operations of the repair personnel at the restoration of the new SS type spacings is proposed. The comparative analysis of the new and the existing SS construction types is carried out. The assessment results of the efficiency, the operational convenience, and the economic effect after the installation of the new type seals are given. The conclusions about the offered construction prospects are made by results of the comparative analysis and the carried-out assessment. The main advantage of this design is the possibility of spacings restoration both in SS and in oil-protecting rings during a short-term stop of a turbine, even without its cooling. This construction was successfully tested on the working K-300-23.5 LMP turbine. However, its adaptation for other turbines is quite possible.

  15. Experiment of drag characteristics of a novel variable geometry flame-holder

    Institute of Scientific and Technical Information of China (English)

    LIU Yang; JIN Jie; WANG Hui-ru; LIU Yu-ying; YANG Mao-lin

    2011-01-01

    A novel variable geometry flame-holder(VGF) based on V-gutter was presented.The structural characteristics of the flame holder were introduced.Experimental study on drag characteristics of the VGF on un-burning and burning states was conducted in a rectangular combustion test rig.The influence of the change of gutter trailing edge width w on pressure recovery in different operating conditions was analyzed emphatically.Furthermore,drag characteristics in different trailing edge width variation modes were discussed.Results show that:(1) Narrowing w can observably raise the total pressure recovery σ but the highest σ is not obtained at minimum w.(2) The relationship of drag coefficient ψ and w in the un-burning conditions can be well expressed in a form of exponential equation(w/d〉0.4).(3) Drag characteristics are not sensitive to the variation modes and speeds of w.(4) In the burning condition,σ decreases with the increasing of w basically and the course can be divided into three stages.The results and experimental data presented in this paper would enhance the phenomenological understanding of this type of VGF,and would contribute to the next experimental study and numerical calculus of this novel VGF.

  16. A Simple Refining Technique of Coconut Oil for Small Holder Industries

    Directory of Open Access Journals (Sweden)

    Sugeng Triyono

    2009-04-01

    Full Text Available A simple refining equipment and process for small holder industries of edible coconut oil has beeninvestigated. The equipment consisted of 20-L filtering and NaOH neutralization bottles. Filtration wasintended to remove impurities such as gums and pigment, while neutralization was to remove free fattyacids (FFA and other non-fat materials. In the experiment, the crude coconut oil was found to have impurityof 0.16%, FFA of 8.02%, saponification number of 270, and water content of 0.33%. The results showed thateither granular activated carbon (GAC or zeolite filtration can be chosen individually to remove physicalimpurity. The GAC or zeolite-filtered coconut oil contained impurity less than the SNI standard of 0.05%.In term of FFA; however, the NaOH neutralized coconut oil did not meet the SNI standard of 0.3%. AfterNaOH neutralization, the GAC filtered oil contained 1.20% FFA; while the zeolite filtered oil contained1.32%. These FFA contents were definitely higher than the SNI standard, but could satisfy APCC standardfor grade IV coconut oil which is 5%. The refined coconut oils could also satisfy the SNI standard ofsaponification number which is 196 – 206 at minimum. In term of water content, either the filtered or theneutralized oil could also satisfy the SNI standard of 0.3%. In short, the proposed technique could helpfarmers refine their raw coconut oil, and hopefully improve its marketability.

  17. Preparing diopside nanoparticle scaffolds via space holder method: Simulation of the compressive strength and porosity.

    Science.gov (United States)

    Abdellahi, Majid; Najafinezhad, Aliakbar; Ghayour, Hamid; Saber-Samandari, Saeed; Khandan, Amirsalar

    2017-08-01

    In the present study, diopside nanopowders were prepared via mechanical milling with eggshell as the calcium source. The space holder method (compaction of ceramic powder and spacer) as one of the most important methods to produce ceramic/metal scaffolds was used to produce diopside scaffolds. For the first time, the effect of the spacer size on mechanical properties and porosity of the obtained scaffolds was experimentally discussed. According to the results obtained, the NaCl particles (as the spacer) with the size of 400-600µm maintained their original spherical shape during the compaction and sintering processes. As a new work, the most important parameters including the spacer type, spacer concentration, spacer size, and applied pressure were considered, and their effects on mechanical properties and porosity of diopside scaffolds were simulated. Gene Expression Programming (GEP), as one of the most branches of the artificial intelligence, was used for simulation process. By using the GEP, two equations were introduced to predict the compressive strength and porosity of the obtained scaffolds with the lowest error values. The 3D diagrams extracted from the model were used to evaluate the combined effect of the process parameters on the compressive strength and porosity of the scaffolds. The GEP model presented in this work has a very low level of error and a high level of the squared regression for predicting the compressive strength and porosity of diopside scaffolds. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Stability of the Baseline Holder in Readout Circuits For Radiation Detectors.

    Science.gov (United States)

    Chen, Y; Cui, Y; O'Connor, P; Seo, Y; Camarda, G S; Hossain, A; Roy, U; Yang, G; James, R B

    2016-02-01

    Baseline holder (BLH) circuits are used widely to stabilize the analog output of application-specific integrated circuits (ASICs) for high-count-rate applications. The careful design of BLH circuits is vital to the overall stability of the analog-signal-processing chain in ASICs. Recently, we observed self-triggered fluctuations in an ASIC in which the shaping circuits have a BLH circuit in the feedback loop. In fact, further investigations showed that methods of enhancing small-signal stabilities cause an even worse situation. To resolve this problem, we used large-signal analyses to study the circuit's stability. We found that a relatively small gain for the error amplifier and a small current in the non-linear stage of the BLH are required to enhance stability in large-signal analysis, which will compromise the properties of the BLH. These findings were verified by SPICE simulations. In this paper, we present our detailed analysis of the BLH circuits, and propose an improved version of them that have only minimal self-triggered fluctuations. We summarize the design considerations both for the stability and the properties of the BLH circuits.

  19. Fatigue behavior of highly porous titanium produced by powder metallurgy with temporary space holders

    Energy Technology Data Exchange (ETDEWEB)

    Özbilen, Sedat [Forschungszentrum Jülich, Institute of Energy and Climate Research (IEK), 52425 Jülich (Germany); Gazi University, Faculty of Technology, Department of Metallurgical and Materials Engineering, Teknikokullar, Ankara (Turkey); Liebert, Daniela [Forschungszentrum Jülich, Institute of Energy and Climate Research (IEK), 52425 Jülich (Germany); Beck, Tilmann [Forschungszentrum Jülich, Institute of Energy and Climate Research (IEK), 52425 Jülich (Germany); University of Kaiserslautern, Lehrstuhl für Werkstoffkunde (WKK), D-67663 Kaiserslautern (Germany); Bram, Martin, E-mail: m.bram@fz-juelich.de [Forschungszentrum Jülich, Institute of Energy and Climate Research (IEK), 52425 Jülich (Germany)

    2016-03-01

    Porous titanium cylinders were produced with a constant amount of temporary space holder (70 vol.%). Different interstitial contents were achieved by varying the starting powders (HDH vs. gas atomized) and manufacturing method (cold compaction without organic binders vs. warm compaction of MIM feedstocks). Interstitial contents (O, C, and N) as a function of manufacturing were measured by chemical analysis. Samples contained 0.34–0.58 wt.% oxygen, which was found to have the greatest effect on mechanical properties. Quasi-static mechanical tests under compression at low strain rate were used for reference and to define parameters for cyclic compression tests. Not unexpectedly, increased oxygen content increased the yield strength of the porous titanium. Cyclic compression fatigue tests were conducted using sinusoidal loading in a servo-hydraulic testing machine. Increased oxygen content was concomitant with embrittlement of the titanium matrix, resulting in significant reduction of compression cycles before failure. For samples with 0.34 wt.% oxygen, R, σ{sub min} and σ{sub max} were varied systematically to estimate the fatigue limit (~ 4 million cycles). Microstructural changes induced by cyclic loading were then characterized by optical microscopy, SEM and EBSD. - Highlights: • Systematic variation of the oxygen content from 0.34 to 0.58 wt.%. • Systematic study of the relationship between fatigue limit and oxygen content. • Critical oxygen equivalent seems to be 0.35 wt.% to avoid embrittlement. • Identification of the failure modes by light microscopy, SEM and EBSD.

  20. Mapping strain fields induced in Zr-based bulk metallic glasses during in-situ nanoindentation by X-ray nanodiffraction

    Energy Technology Data Exchange (ETDEWEB)

    Gamcová, J.; Bednarčík, J.; Franz, H. [DESY, Notkestraße 85, Hamburg 22547 (Germany); Mohanty, G.; Wehrs, J.; Michler, J. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkerstraße 39, Thun 3602 (Switzerland); Michalik, Š. [Institute of Physics ASCR, Na Slovance 2, Praha 18221 (Czech Republic); Krywka, C. [HZG, Institut für Werkstoffforschung, Notkestraße 85, Hamburg 22547 (Germany); Breguet, J. M. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkerstraße 39, Thun 3602 (Switzerland); Alemnis GmbH, Feuerwerkerstraße 39, Thun 3602 (Switzerland)

    2016-01-18

    A pioneer in-situ synchrotron X-ray nanodiffraction approach for characterization and visualization of strain fields induced by nanoindentation in amorphous materials is introduced. In-situ nanoindentation experiments were performed in transmission mode using a monochromatic and highly focused sub-micron X-ray beam on 40 μm thick Zr-based bulk metallic glass under two loading conditions. Spatially resolved X-ray diffraction scans in the deformed volume of Zr-based bulk metallic glass covering an area of 40 × 40 μm{sup 2} beneath the pyramidal indenter revealed two-dimensional map of elastic strains. The largest value of compressive elastic strain calculated from diffraction data at 1 N load was −0.65%. The region of high elastic compressive strains (<−0.3%) is located beneath the indenter tip and has radius of 7 μm.