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Sample records for bulk negative-index material

  1. Bulk isotropic negative-index material design for infrared

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Malureanu, Radu; Lavrinenko, Andrei

    Responding to the strong call for isotropic bulk negative index material we propose a Split Cube in Car-cass design. It shows negative refractive index -1.5, figure-of-merit 2 and transmittivity 30% for one layer at the telecommunication wavelength 1.6 μm. Effective parameters converge fast with a...... number of layers. The effective parameters retrieval method based on the wave propagation simulation is proposed and compared with standard procedure. It is shown that standard restoration method while used for the S-parameters spectra calculations with pulse sources excitation can contain an error...

  2. Nested structures approach for bulk 3D negative index materials

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Malureanu, Radu; Lavrinenko, Andrei

    2009-01-01

    We propose a generic conceptual idea to obtain bulk 3D negative index metamaterials, which exhibit isotropic properties. The design is based on the nested structures approach, when one element providing magnetic response is inserted into another design with negative dielectric constant. Both...

  3. The split cube in a cage: bulk negative-index material for infrared applications

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Menzel, C.; Rockstuhl, C.;

    2009-01-01

    We propose the split cube in a cage (SCiC) design for application in producing a bulk metamaterial. Applying realistic material data for thin silver films, we observe an immediate convergence of the effective parameters obtained with a number of layers towards the bulk properties. Results are obt...

  4. Energy flow in negative index materials

    Institute of Scientific and Technical Information of China (English)

    Lorenzo Bolla; Michele Midrio; Carlo G. Someda

    2004-01-01

    From Maxwell's equations, we compute the speed and the direction of propagation of active power refractedfrom air into a negative index material. We prove, both analytically and numerically that the power mayrefract positively even if phase fronts refract negatively. Considerations on the usage of ray optics inproblems involving negative index materials are drawn.

  5. Numerical study of electromagnetic waves interacting with negative index materials.

    Science.gov (United States)

    Kolinko, Pavel; Smith, David

    2003-04-01

    We study numerically the electromagnetic scattering properties of structures with negative indices of refraction. To perform this analysis, we utilize a commercial finite-element based electromagnetic solver (HFSS, Ansoft), in which a negative index material can be formed from mesh elements whose permittivity and permeability are both negative. In particular, we investigate the expected transmission characteristics of a finite beam incident on negative index prisms and lenses. We also confirm numerically the predicted superlens effect of an image formed by a planar slab with index n=-1, using two subwavelength (ë/20) slits as objects. PMID:19461776

  6. Surface waves excited from negative-index materials

    International Nuclear Information System (INIS)

    Studies on electromagnetic surface waves along the surface of a finitely thick plate made from negative-index materials are presented in this paper. Through theoretical analysis we worked out requirements on permeability and permittivity for surface waves to exist. Comparing with the model of a plate with infinite thickness, the one of finite thickness shows released requirements, leading to potential applications in guiding wave and developing radiation sources. With the help of particle-in-cell simulations, we examined theoretical predictions and demonstrated field distributions of surface waves. - Highlights: • Surface modes along a finitely thick plate with/without PEC substrate are studied. • Both positive-index material and negative-index material models are investigated. • Requirements are obtained to make surface waves exist. • The requirements are released comparing with an infinitely thick model. • Higher frequency of some surface modes can be excited with thicker NIM plate

  7. Defect in photonic crystal with negative index material

    Institute of Scientific and Technical Information of China (English)

    TANG Kang-song; XIANG Yuan-jiang; WEN Shuang-chun

    2006-01-01

    The transmission property of the photonic crystal containing negative index material is analyzed by means of transfer matrix method.It is demonstrated that a defect mode appears in the conventional Bragg gap and the defect mode is sensitive to the position of the defect cell.For the first time to our knowledge we introduce two defects into such a structure and discuss the dependence of the transmission on the interval of the two defect cells.It is found that a wide degenerate defect mode appears in the Bragg gap,and this degenerate defect mode splits into two different defect modes when the two defect cells become closer.

  8. Negative Index Materials and Plasmonic Antennas Based Nanocouplers

    DEFF Research Database (Denmark)

    Andryieuski, Andrei

    This thesis describes the development, design and fabrication of the nanocoupler that is a device coupling light from conventional optical fiber to the nanosize plasmonic slot waveguide. This device can decrease the coupling region to several micrometers providing compact interface between an...... optical fiber and future optical integrated circuit. Multiple nanocoupler possibilities are analyzed. Two realizations are investigated: negative index metamaterial and plasmonic nanoantenna based. The cubic symmetric negative index metamaterial Split cube in Cage and Split cube in Carcass designs for the...... geometrical parameters of the nanoantenna couplers are found out. The best performance is shown by the battle axe nanocoupler that has an antenna figure of merit equal to 1.8 μm2 for five antenna periods. That is 90 times larger than antenna figure of merit for the waveguide without nanocoupler (0.02 μm2...

  9. Self-assembled hexagonal double fishnets as negative index materials

    CERN Document Server

    Lodewijks, Kristof; Van Roy, Willem; Borghs, Gustaaf; Van Dorpe, Pol

    2010-01-01

    We show experimentally the successful use of colloidal lithography for the fabrication of negative index metamaterials in the near-infrared wavelength range. In particular, we investigated a specific implementation of the widely studied double fishnet metamaterials, consisting of a gold-silica-gold layer stack perforated by a hexagonal array of round holes. Tuning of the hole diameter allows us to tailor these self-assembled metamaterials both as single- ({\\epsilon} < 0) and double ({\\epsilon} < 0 and {\\mu} < 0) negative metamaterials.

  10. Stability criterion for Gaussian pulse propagation through negative index materials

    International Nuclear Information System (INIS)

    We analyze the dynamics of propagation of a Gaussian light pulse through a medium having a negative index of refraction employing the recently reported projection operator technique. The governing modified nonlinear Schroedinger equation, obtained by taking into account the Drude dispersive model, is expressed in terms of the parameters of Gaussian pulse, called collective variables, such as width, amplitude, chirp, and phase. This approach yields a system of ordinary differential equations for the evolution of all the pulse parameters. We demonstrate the dependence of stability of the fixed-point solutions of these ordinary differential equations on the linear and nonlinear dispersion parameters. In addition, we validate the analytical approach numerically utilizing the method of split-step Fourier transform.

  11. Plasmon-Enhanced Photonic Crystal Negative Index Materials for Superlensing Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Negative index materials (NIMs) offer tremendous potential for the formation of highly compact as well as large-area deployable thin-film optical components. Omega...

  12. Nonlinear excitations in negative index materials: Modulational instability and solitary wave solutions

    Science.gov (United States)

    Sharma, Vivek Kumar; Goyal, Amit

    2016-05-01

    We explore the modulational instability and existence of dark, bright solitary wave solutions in negative index-materials (NIMs) modeled by generalized nonlinear Schrödinger equation with competing cubic-quintic and higher-order nonlinearities with dispersive permittivity and permeability. Parameter domains are delineated in which these ultrashort pulses exist in NIMs. Unlike the ordinary materials, these novel excitations occur for different signs of dispersion, Kerr and non-Kerr nonlinearities.

  13. Creating double negative index materials using the Babinet principle with one metasurface

    OpenAIRE

    Zhang, Lei; Koschny, Thomas; Soukoulis, Costas M.

    2013-01-01

    Metamaterials are patterned metallic structures which permit access to a novel electromagnetic response, negative index of refraction, impossible to achieve with naturally occurring materials. Using the Babinet principle, the complementary split ring resonator (SRR) is etched in a metallic plate to provide negative \\epsilon, with perpendicular direction. Here we propose a new design, etched in a metallic plate to provide negative magnetic permeability \\mu, with perpendicular direction. The co...

  14. Nested structures approach in designing an isotropic negative-index material for infrared

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Malureanu, Radu; Lavrinenko, Andrei

    2009-01-01

    We propose a new generic approach for designing isotropic metamaterial with nested cubic structures. As an example, a three-dimensional isotropic unit cell design "Split Cube in Cage" (SCiC) is shown to exhibit an effective negative refractive index on infrared wavelengths. We report on the refra...... refractive index reaching -2.3 and the figure of merit as high as 2.7. The structure exhibits potential for application as a building block of isotropic negative-index materials....

  15. Modulation instability in a triangular three-core coupler with a negative-index material channel

    Science.gov (United States)

    Shafeeque Ali, A. K.; Nithyanandan, K.; Porsezian, K.; Maimistov, Andrei I.

    2016-03-01

    A theoretical investigation of the modulation instability (MI) in the three core triangular oppositely directed coupler with negative index material channel is presented. This class of couplers have an effective feedback mechanism due to the opposite directionality of the phase velocities in the negative and positive index channels. It is found that the MI in the nonlinear three core triangular oppositely directed coupler is significantly influenced by the ratio of the forward- to backward-propagating wave power and nonlinearity. Also, in the case of the normal dispersion regime a threshold-like behavior is observed, whereas this behavior is not identified in the anomalous dispersion regime. For the asymmetric case (h\

  16. Influence of birefringence in the instability spectra of oppositely directed coupler with negative index material channel

    Science.gov (United States)

    Shafeeque Ali, A. K.; Nithyanandan, K.; Porsezian, K.; Maimistov, Andrei I.

    2016-02-01

    A theoretical investigation on the influence of birefringence in the modulational instability (MI) spectra of an oppositely directed coupler (ODC) with a negative index material (NIM) channel is presented. We study the effect of birefringence on MI in linear and circular birefringent ODCs for both normal and anomalous dispersion regimes. It is found that besides the instability band due to nonlinear positive index material (PIM) and negative index material (NIM) channels, new symmetric instability regions are observed as a result of birefringent effects. Also defocusing nonlinearity suppresses the NIM band in the normal dispersion regime, but in the anomalous dispersion regime the defocusing nonlinearity enhances the gain of the NIM band. In contrast to the case of linear birefringence, in terms of MI gain from circular birefringence, only two birefringent bands dominate: the inherently PIM and NIM bands. This preponderance is attributed to the fact that the cross-phase modulation effect for the case of circular birefringence is stronger, thus allowing a better coupling between the beams, which results in the enhancement of the gain. Therefore, the manipulation of MI and solitons in an ODC is better performed when the birefringence is circular rather than linear. Here we report how to generate and manipulate MI and solitons in birefringent ODCs with a particular emphasis on a NIM channel.

  17. Physics of Negative Refraction and Negative Index Materials Optical and Electronic Aspects and Diversified Approaches

    CERN Document Server

    Krowne, Clifford M

    2007-01-01

    This book deals with the subject of optical and electronic negative refraction (NR) and negative index materials NIM). Diverse approaches for achieving NR and NIM are covered, such as using photonic crystals, phononic crystals, split-ring resonators (SRRs) and continuous media, focusing of waves, guided-wave behavior, and nonlinear effects. Specific topics treated are polariton theory for LHMs (left handed materials), focusing of waves, guided-wave behavior, nonlinear optical effects, magnetic LHM composites, SRR-rod realizations, low-loss guided-wave bands using SRR-rods unit cells as LHMs, NR of electromagnetic and electronic waves in uniform media, field distributions in LHM guided-wave structures, dielectric and ferroelectric NR bicrystal heterostructures, LH metamaterial photonic-crystal lenses, subwavelength focusing of LHM/NR photonic crystals, focusing of sound with NR and NIMs, and LHM quasi-crystal materials for focusing.

  18. Dispersion, spatial growth rate, and start current of a Cherenkov free-electron laser with negative-index material

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuanyuan; Wei, Yanyu; Jiang, Xuebing; Tang, Xianfeng; Shi, Xianbao; Gong, Yubin [National Key Laboratory of Science and Technology on Vacuum Electronics, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China); Li, Dazhi [Institute for Laser Technology, Suita, Osaka 565-0781 (Japan); Takano, Keisuke; Nakajima, Makoto [Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0781 (Japan); Feng, Jinjun [Beijing Vacuum Electronics Research Institute, Beijing 100016 (China); Miyamoto, Shuji [Laboratory of Advanced Science and Technology for Industry, University of Hyogo, Ako, Hyogo 678-1205 (Japan)

    2015-08-15

    We present an analysis of a Cherenkov free-electron laser based on a single slab made from negative-index materials. In this system, a flat electron beam with finite thickness travelling close to the surface of the slab interacts with the copropagating electromagnetic surface mode. The dispersion equation for a finitely thick slab is worked out and solved numerically to study the dispersion relation of surface modes supported by negative-index materials, and the calculations are in good agreement with the simulation results from a finite difference time domain code. We find that under suitable conditions there is inherent feedback in such a scheme due to the characteristics of negative-index materials, which means that the system can oscillate without external reflectors when the beam current exceeds a threshold value, i.e., start current. Using the hydrodynamic approach, we setup coupled equations for this system, and solve these equations analytically in the small signal regime to obtain formulas for the spatial growth rate and start current.

  19. Dispersion, spatial growth rate, and start current of a Cherenkov free-electron laser with negative-index material

    International Nuclear Information System (INIS)

    We present an analysis of a Cherenkov free-electron laser based on a single slab made from negative-index materials. In this system, a flat electron beam with finite thickness travelling close to the surface of the slab interacts with the copropagating electromagnetic surface mode. The dispersion equation for a finitely thick slab is worked out and solved numerically to study the dispersion relation of surface modes supported by negative-index materials, and the calculations are in good agreement with the simulation results from a finite difference time domain code. We find that under suitable conditions there is inherent feedback in such a scheme due to the characteristics of negative-index materials, which means that the system can oscillate without external reflectors when the beam current exceeds a threshold value, i.e., start current. Using the hydrodynamic approach, we setup coupled equations for this system, and solve these equations analytically in the small signal regime to obtain formulas for the spatial growth rate and start current

  20. A Three-Dimensionally Isotropic and Perfectly Vacuum-Impedance-Matched Negative-Index Material

    Science.gov (United States)

    Shen, Jian Qi

    2014-12-01

    A new scenario for realizing a gain left-handed atomic vapor medium based on both dressed-state mixed-parity transitions (for simultaneous electric- and magnetic-dipole resonance) and incoherently-pumped population transfer (for high gain amplification) in a four-level atomic system is suggested. Dressed-state assisted simultaneous electric- and magnetic-dipole allowed transitions in such a four-level atomic system (of, e.g., neutral alkali-metal atoms such as lithium and potassium atoms) are utilized for achieving negative refractive index with impedance perfectly matched to vacuum. The attractive features of the present scenario include: i) three-dimensionally isotropic negative indices; ii) incoherent-gain wave amplification; iii) perfect impedance matching to vacuum. All these important properties of the double-negative medium would have potential applications in designing some optical and photonic devices, including particularly subwavelength focusing system and negative-index superlens for perfect imaging.

  1. Bulk materials handling review

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-02-15

    The paper provides details of some of the most important coal handling projects and technologies worldwide. It describes development by Aubema Crushing Technology GmbH, Bedeschi, Cimbria Moduflex, DBT, Dynamic Air Conveying Systems, E & F Services, InBulk Technologies, Nord-Sen Metal Industries Ltd., Pebco Inc, Primasonics International Ltd., R.J.S. Silo Clean (International) Ltd., Takraf GmbH, and The ACT Group. 17 photos.

  2. Towards negative index self-assembled metamaterials

    CERN Document Server

    Fruhnert, Martin; Lederer, Falk; Rockstuhl, Carsten

    2016-01-01

    We investigate the magnetic response of meta-atoms that can be fabricated by a bottom-up technique. Usually such meta-atoms consist of a dielectric core surrounded by a large number of solid metallic nanoparticles. In contrast to those meta-atoms considered thus far, we study here for the first time hollow metallic nanoparticles (shells). In doing so we solve one of the most pertinent problems of current self-assembled metamaterials, namely implementing meta-atoms with sufficiently large resonance strength and small absorption. Both conditions have to be met for deep sub-wavelength meta-atoms to obtain effectively homogeneous metamaterials which may be meaningfully described by negative material parameters. Eventually we show that by using these findings self-assembled negative index materials come in reach.

  3. Structures with negative index of refraction

    Science.gov (United States)

    Soukoulis, Costas M.; Zhou, Jiangfeng; Koschny, Thomas; Zhang, Lei; Tuttle, Gary

    2011-11-08

    The invention provides simplified negative index materials (NIMs) using wire-pair structures, 4-gap single ring split-ring resonator (SRR), fishnet structures and overleaf capacitor SRR. In the wire-pair arrangement, a pair of short parallel wires and continuous wires are used. In the 4-gap single-ring SRR, the SRRs are centered on the faces of a cubic unit cell combined with a continuous wire type resonator. Combining both elements creates a frequency band where the metamaterial is transparent with simultaneously negative .di-elect cons. and .mu.. In the fishnet structure, a metallic mesh on both sides of the dielectric spacer is used. The overleaf capacitor SRR changes the gap capacities to small plate capacitors by making the sections of the SRR ring overlap at the gaps separated by a thin dielectric film. This technique is applicable to conventional SRR gaps but it best deploys for the 4-gap single-ring structures.

  4. Dynamics of evanescent matter waves in negative-index media

    Science.gov (United States)

    Hamamda, M.; Bocvarski, V.; Perales, F.; Baudon, J.; Dutier, G.; Mainos, C.; Boustimi, M.; Ducloy, M.

    2010-11-01

    Semi-evanescent and evanescent matter waves produced by an atom wave packet impinging on a repulsive barrier can be back-refracted and reconstructed by the application of negative-index 'comoving' potential pulses. One shows that those collapses and revivals generate a matter wave confined on both sides of the barrier border ('surface matter wave') and should be observable via the retardation of atom reflection from the barrier interface. This property, joined to the possibility recently demonstrated of inducing negative refraction of atom waves, makes such potentials a matter-wave counterpart of negative-index materials or 'meta materials' well known in light optics.

  5. Chiral Negative-Index Metamaterials in Terahertz

    OpenAIRE

    Zhang, Shuang; Park, Yong-Shik; Li, Jensen; Lu, Xinchao; Zhang, Weili; Zhang, Xiang

    2008-01-01

    Negative index metamaterials (NIMs) give rise to unusual and intriguing properties and phenomena, which may lead to important applications such as superlens, subwavelength cavity and slow light devices. However, the negative refractive index in metamaterials normally requires a stringent condition of simultaneously negative permittivity and negative permeability. A new class of negative index metamaterials - chiral NIMs, have been recently proposed. In contrast to the conventional NIMs, chira...

  6. Chiral Negative-Index Metamaterials in Terahertz

    CERN Document Server

    Zhang, Shuang; Li, Jensen; Lu, Xinchao; Zhang, Weili; Zhang, Xiang

    2008-01-01

    Negative index metamaterials (NIMs) give rise to unusual and intriguing properties and phenomena, which may lead to important applications such as superlens, subwavelength cavity and slow light devices. However, the negative refractive index in metamaterials normally requires a stringent condition of simultaneously negative permittivity and negative permeability. A new class of negative index metamaterials - chiral NIMs, have been recently proposed. In contrast to the conventional NIMs, chiral NIMs do not require the above condition, thus presenting a very robust route toward negative refraction. Here we present the first experimental demonstration of a chiral metamaterial exhibiting negative refractive index down to n=-5 at terahertz frequencies, with only a single chiral resonance. The strong chirality present in the structure lifts the degeneracy for the two circularly polarized waves and relieves the double negativity requirement. Chiral NIM are predicted to possess intriguing electromagnetic properties t...

  7. Controlling the second-harmonic in a phase matched negative-index metamaterial

    OpenAIRE

    Rose, Alec; Huang, Da; Smith, David R.

    2011-01-01

    Nonlinear metamaterials (NLMMs) have been predicted to support new and exciting domains in the manipulation of light, including novel phase matching schemes for wave mixing. Most notable is the so-called nonlinear-optical mirror, in which a nonlinear negative-index medium emits the generated frequency towards the source of the pump. For the first time, we experimentally demonstrate the nonlinear-optical mirror effect in a bulk negative-index NLMM, along with two other novel phase matching con...

  8. Negative-Index Media for Matter Waves

    Science.gov (United States)

    Perales, F.; Bocvarski, V.; Baudon, J.; Hamamda, M.; Grucker, J.; Dutier, G.; Mainos, C.; Boustimi, M.; Ducloy, M.

    2010-02-01

    One reviews the recently introduced field of matter-wave "meta-optics", i.e. the extension of optical negative-index media (NIM) to atom optics. After emphasizing the differences with light meta-optics and particularly the necessary transient character of NIM's in atom optics, we present the way of generating matter-wave NIM's and their general properties: negative refraction, atom meta-lenses. Finally their specific features are reviewed: longitudinal wave packet narrowing associated to a time-reversal effect, transient revivals of evanescent matter waves and atom reflection echoes at a potential barrier.

  9. High Performance Bulk Thermoelectric Materials

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Zhifeng [Boston College, Chestnut Hill, MA (United States)

    2013-03-31

    Over 13 plus years, we have carried out research on electron pairing symmetry of superconductors, growth and their field emission property studies on carbon nanotubes and semiconducting nanowires, high performance thermoelectric materials and other interesting materials. As a result of the research, we have published 104 papers, have educated six undergraduate students, twenty graduate students, nine postdocs, nine visitors, and one technician.

  10. PHONON ECHOES IN BULK AND POWDERED MATERIALS

    OpenAIRE

    Kajimura, K.

    1981-01-01

    Experimental and theoretical studies of phonon echoes in bulk and powdered materials are reviewed. Phonon echoes have been observed in many materials such as bulk piezoelectric crystals, paramagnets, glasses, doped semiconductors, and piezoelectric, magnetic, and metallic powders, etc. The echoes arise from a time reversal of the phase, like spin echoes, of a primary pulsed acoustic excitation due to a second acoustic or rf pulse. The phase reversal occurs through the nonlinear interactions o...

  11. Reluctance motors with bulk HTS material

    International Nuclear Information System (INIS)

    In recent years we have successfully designed, built and tested several reluctance motors with YBCO bulk material incorporated into the rotor, working at 77 K. Our last motor type SRE150 was tested up to 200 kW. The aim of our investigations is the construction of motors with extremely high power density and dynamics. In comparison to conventional motor types the advantage of HTS reluctance motors with respect to size and dynamics could be demonstrated. Some fields of possible future applications will be described. These motors show a significant improvement in performance using high quality HTS bulk elements in the rotor. Until now the motor parameters have been limited by the current density which could be obtained in the bulk material at 77 K and by the geometric dimensions of the segments available. Therefore we expect further improvements in the case of these materials. Since the total motor including stator and rotor is working at low temperature we have to optimize the windings and the magnetic circuit to these operation conditions. A new design of a 200 kW motor in order to achieve increased power density and the theoretical results of our calculations will be shown

  12. A Batch Feeder for Inhomogeneous Bulk Materials

    Science.gov (United States)

    Vislov, I. S.; Kladiev, S. N.; Slobodyan, S. M.; Bogdan, A. M.

    2016-04-01

    The work includes the mechanical analysis of mechanical feeders and batchers that find application in various technological processes and industrial fields. Feeders are usually classified according to their design features into two groups: conveyor-type feeders and non-conveyor feeders. Batchers are used to batch solid bulk materials. Less frequently, they are used for liquids. In terms of a batching method, they are divided into volumetric and weighting batchers. Weighting batchers do not provide for sufficient batching accuracy. Automatic weighting batchers include a mass controlling sensor and systems for automatic material feed and automatic mass discharge control. In terms of operating principle, batchers are divided into gravitational batchers and batchers with forced feed of material using conveyors and pumps. Improved consumption of raw materials, decreased loss of materials, ease of use in automatic control systems of industrial facilities allows increasing the quality of technological processes and improve labor conditions. The batch feeder suggested by the authors is a volumetric batcher that has no comparable counterparts among conveyor-type feeders and allows solving the problem of targeted feeding of bulk material batches increasing reliability and hermeticity of the device.

  13. Assessment of bioburden encapsulated in bulk materials

    Science.gov (United States)

    Schubert, Wayne W.; Newlin, Laura; Chung, Shirley Y.; Ellyin, Raymond

    2016-05-01

    The National Aeronautics and Space Administration (NASA) imposes bioburden limitations on all spacecraft destined for solar system bodies that might harbor evidence of extant or extinct life. The subset of microorganisms trapped within solid materials during manufacture and assembly is referred to as encapsulated bioburden. In the absence of spacecraft-specific data, NASA relies on specification values to estimate total spacecraft encapsulated bioburden, typically 30 endospores/cm3 or 300 viable cells/cm3 in non-electronic materials. Specification values for endospores have been established conservatively, and represent no less than an order of magnitude greater abundance than that derived from empirical assessments of actual spacecraft materials. The goal of this study was to generate data germane to determining whether revised bulk encapsulated material values (lower than those estimated by historical specifications) tailored specifically to the materials designated in modern-day spacecraft design could be used, on a case-by-case basis, to comply with planetary protection requirements. Organic materials having distinctly different chemical properties and configurations were selected. This required more than one experimental and analytical approach. Filtration was employed for liquid electrolytes, lubricants were suspended in an aqueous solution and solids (wire and epoxy sealant) were cryogenically milled. The final data characteristic for all bioburden estimates was microbial colony formation in rich agar growth medium. To assess survival potential, three non-spore-forming bacterial cell lines were systematically encapsulated in an epoxy matrix, liberated via cryogenic grinding, and cultured. Results suggest that bulk solid materials harbor significantly fewer encapsulated microorganisms than are estimated by specification values. Lithium-ion battery electrolyte reagents housed fewer than 1 CFU/cm3. Results also demonstrated that non-spore-forming microorganisms

  14. Integration of bulk piezoelectric materials into microsystems

    Science.gov (United States)

    Aktakka, Ethem Erkan

    Bulk piezoelectric ceramics, compared to deposited piezoelectric thin-films, provide greater electromechanical coupling and charge capacity, which are highly desirable in many MEMS applications. In this thesis, a technology platform is developed for wafer-level integration of bulk piezoelectric substrates on silicon, with a final film thickness of 5-100microm. The characterized processes include reliable low-temperature (200°C) AuIn diffusion bonding and parylene bonding of bulk-PZT on silicon, wafer-level lapping of bulk-PZT with high-uniformity (+/-0.5microm), and low-damage micro-machining of PZT films via dicing-saw patterning, laser ablation, and wet-etching. Preservation of ferroelectric and piezoelectric properties is confirmed with hysteresis and piezo-response measurements. The introduced technology offers higher material quality and unique advantages in fabrication flexibility over existing piezoelectric film deposition methods. In order to confirm the preserved bulk properties in the final film, diaphragm and cantilever beam actuators operating in the transverse-mode are designed, fabricated and tested. The diaphragm structure and electrode shapes/sizes are optimized for maximum deflection through finite-element simulations. During tests of fabricated devices, greater than 12microm PP displacement is obtained by actuation of a 1mm2 diaphragm at 111kHz with properties of bulk-PZT5A are mostly preserved without any necessity of repolarization. Three generations of resonant vibration energy harvesters are designed, simulated and fabricated to demonstrate the competitive performance of the new fabrication process over traditional piezoelectric deposition systems. An unpackaged PZT/Si unimorph harvester with 27mm3 active device volume produces up to 205microW at 1.5g/154Hz. The prototypes have achieved the highest figure-of-merits (normalized-power-density x bandwidth) amongst previously reported inertial energy harvesters. The fabricated energy harvester is

  15. Neutron moisture gage for bulk material

    International Nuclear Information System (INIS)

    Desing and operation of neutron moisture gage of bulk materials intended for the determination of moisture of coke, agglomerated charge, and iron ore concentrate in black metallurgy is described. The moisture gage operates both under ''measurement'' and ''calibration'' conditions, contains a fast neutron source, and two groups of slow neutron detectors. Technical and economic efficiency of the moisture gage utilization consists in the improved accuracy of moisture detection at the expense of more accurate calibration, optimum arrangement of the carriage in a hopper, and stabilization of detector temperature. The device service is also simplified

  16. Subwavelength resolution with a negative-index metamaterial superlens

    Science.gov (United States)

    Aydin, Koray; Bulu, Irfan; Ozbay, Ekmel

    2007-06-01

    Negative-index metamaterials are candidates for imaging objects with sizes smaller than a half-wavelength. The authors report an impedance-matched, low loss negative-index metamaterial superlens that is capable of resolving subwavelength features of a point source with a 0.13λ resolution, which is the highest resolution achieved by a negative-index metamaterial. By separating two point sources with a distance of λ /8, they were able to detect two distinct peaks on the image plane. They also showed that the metamaterial based structure has a flat lens behavior.

  17. Bulk nanoscale materials in steel products

    International Nuclear Information System (INIS)

    Although a number of nanoscale metallic materials exhibit interesting mechanical properties the fabrication paths are often complex and difficult to apply to bulk structural materials. However a number of steels which exhibit combinations of plasticity and phase transitions can be deformed to produce ultra high strength levels in the range 1 to 3 GPa. The resultant high stored energy and complex microstructures allow new nanoscale structures to be produced by combinations of recovery and recrystallisation. The resultant structures exhibit totally new combinations of strength and ductility to be achieved. In specific cases this also enables both the nature of the grain boundary structure and the spatial variation in structure to be controlled. In this presentation both the detailed microstructural features and their relation to the strength, work-hardening capacity and ductility will be discussed for a number of martensitic and austenitic steels.

  18. Focus modulation of cylindrical vector beams through negative-index grating lenses

    Science.gov (United States)

    Wang, Shengming; Xu, Ji; Zhong, Yi; Ren, Rong; Lu, Yunqing; Wan, Hongdan; Wang, Jin; Ding, Jianping

    2016-08-01

    A cylindrically symmetric negative-index grating lens composed of unitary material is proposed as an effective method to modulate the focusing of cylindrical vector beams (CVBs). The grating parameters are designed to obtain an appropriate negative index, and the lens profile is tailored to realize the constructive interference. The plano-concave lens is parameterized to achieve desired focal length and the plano-cone lens is proposed to obtain large depth of focus. An optical needle is generated with radially polarized incidence, and an optical tube is achieved with incidence of azimuthal polarization. Moreover, the presented modulation methods can be applied for any arbitrary polarized CVBs. This work offers a more flexible and effective approach to design negative-index lenses for subwavelength focusing of CVBs, which has potential application value in related areas, such as optical trapping, and other nano-optics fields.

  19. Modulation instability of structured-light beams in negative-index metamaterials

    CERN Document Server

    Silahli, Salih Z; Litchinitser, Natalia M

    2016-01-01

    One of the most fundamental properties of isotropic negative-index metamaterials, namely opposite directionality of the Poynting vector and the wavevector, enable many novel linear and nonlinear regimes of light-matter interactions. Here, we predict distinct characteristics of azimuthal modulation instability of optical vortices with different topological charges in negative-index metamaterials with Kerr-type and saturable nonlinearity. We derive an analytical expression for the spatial modulation-instability gain for the Kerr-nonlinearity case and show that a specific condition relating the diffraction and the nonlinear lengths must be fulfilled for the azimuthal modulation instability to occur. Finally, we investigate the rotation of the necklace beams due to the transfer of orbital angular momentum of the generating vortex onto the movement of solitary necklace beams. We show that the direction of rotation is opposite in the positive- and negative-index materials.

  20. Sub-picosecond optical switching with a negative index metamaterial

    Energy Technology Data Exchange (ETDEWEB)

    Dani, Keshav M [Los Alamos National Laboratory; Upadhya, Prashant C [Los Alamos National Laboratory; Zahyum, Ku [CHTM-UNM

    2009-01-01

    Development of all-optical signal processing, eliminating the performance and cost penalties of optical-electrical-optical conversion, is important for continu,ing advances in Terabits/sec (Tb/s) communications.' Optical nonlinearities are generally weak, traditionally requiring long-path, large-area devicesl,2 or very high-Q, narrow-band resonator structures.3 Optical metamaterials offer unique capabilities for optical-optical interactions. Here we report 600 femtosecond (fs) all-optical modulation using a fIShnet (2D-perforated metallamorphous-Si (a-Si)/metal film stack) negative-index meta material with a structurally tunable broad-band response near 1.2 {micro}m. Over 20% modulation (experimentally limited) is achieved in a path length of only 116 nm by photo-excitation of carriers in the a-Si layer. This has the potential for Tb/s aU-optical communication and will lead to other novel, compact, tunable sub-picosecond (ps) photonic devices.

  1. LOGISTICAL CRITERIONS AND STRATEGIES FOR STORAGE OF BULK MATERIALS

    OpenAIRE

    Péter Telek

    2009-01-01

    The aim of my paper is to analyze the applicability of criterions used for selection of storage methods of individual units and general logistic strategies for storage of bulk materials. To reach this aim paper gives an overview about the advanced storage methods of bulk materials and their application possibilities. The second part shows the main criterions and logistic strategies in deep and describes their usability for bulk materials.

  2. Eco Issues in Bulk Materials Handling Technologies in Ports

    Directory of Open Access Journals (Sweden)

    Nenad Zrnić

    2011-09-01

    Full Text Available This paper deals with eco issues in bulk materials handling in ports. Solid, free-flowing materials are said to be in bulk. Bulk materials handling is very difficult, because it incorporates all the features of liquids, gasses and mass solids. Energy efficiency, dust emissions in nearby environment, dust explosions, jamming, noise, handling of hazardous materials and protection of materials from contamination are issues that will be considered in this paper. Here are also presented possible solutions for some of these issues

  3. Macroscopic and direct light propulsion of bulk graphene material

    CERN Document Server

    Zhang, Tengfei; Wu, Yingpeng; Xiao, Peishuang; Yi, Ningbo; Lu, Yanhong; Ma, Yanfeng; Huang, Yi; Zhao, Kai; Yan, Xiao-Qing; Liu, Zhi-Bo; Tian, Jian-Guo; Chen, Yongsheng

    2015-01-01

    It has been a great challenge to achieve the direct light manipulation of matter on a bulk scale. In this work, the direct light propulsion of matter was observed on a macroscopic scale for the first time using a bulk graphene based material. The unique structure and properties of graphene and the morphology of the bulk graphene material make it capable of not only absorbing light at various wavelengths but also emitting energetic electrons efficiently enough to drive the bulk material following Newtonian mechanics. Thus, the unique photonic and electronic properties of individual graphene sheets are manifested in the response of the bulk state. These results offer an exciting opportunity to bring about bulk scale light manipulation with the potential to realize long-sought proposals in areas such as the solar sail and space transportation driven directly by sunlight.

  4. Material profile influences in bulk-heterojunctions

    OpenAIRE

    Roehling, J.D.; Rochester, C.W.; Ro, H.W.; Wang, P.; Majewski, J; Batenburg, Joost; Arslan, I; Delongchamp, D.M.; Moulé, A.J.

    2014-01-01

    The morphology in mixed bulk-heterojunction films are compared using three different quantitative measurement techniques. We compare the vertical composition changes using high-angle annular dark-field scanning transmission electron microscopy with electron tomography and neutron and x-ray reflectometry. The three measurement techniques yield qualitatively comparable vertical concentration measurements. The presence of a metal cathode during thermal annealing is observed to alter the fulleren...

  5. Strong effect of surfaces on resolution limit of negative-index "superlens"

    OpenAIRE

    Bratkovsky, A. M.; A. Cano; Levanyuk, A. P.

    2004-01-01

    We show that subwavelength imaging by negative index materials (NIM), related to their "soft" electromagnetic response, is very (and non trivially) sensitive to the surface properties. A minute deviation of dielectric permittivity epsilon or magnetic permeability mu from the ideal values epsilon = mu = -1 in thin surface layer(s) results in drastic reduction of the resolution limit of a NIM slab. There may be a gap in the polariton spectrum and this would allow establishment of a stationary r...

  6. Enhancing bulk superconductivity by engineering granular materials

    Science.gov (United States)

    Mayoh, James; García García, Antonio

    2014-03-01

    The quest for higher critical temperatures is one of the main driving forces in the field of superconductivity. Recent theoretical and experimental results indicate that quantum size effects in isolated nano-grains can boost superconductivity with respect to the bulk limit. Here we explore the optimal range of parameters that lead to an enhancement of the critical temperature in a large three dimensional array of these superconducting nano-grains by combining mean-field, semiclassical and percolation techniques. We identify a broad range of parameters for which the array critical temperature, TcArray, can be up to a few times greater than the non-granular bulk limit, Tc 0. This prediction, valid only for conventional superconductors, takes into account an experimentally realistic distribution of grain sizes in the array, charging effects, dissipation by quasiparticles and limitations related to the proliferation of thermal fluctuations for sufficiently small grains. For small resistances we find the transition is percolation driven. Whereas at larger resistances the transition occurs above the percolation threshold due to phase fluctuations. JM acknowledes support from an EPSRC Ph.D studentship, AMG acknowledges support from EPSRC, grant No. EP/I004637/1, FCT, grant PTDC/FIS/111348/2009 and a Marie Curie International Reintegration Grant PIRG07-GA-2010-268172.

  7. Modulation instability of structured-light beams in negative-index metamaterials

    Science.gov (United States)

    Silahli, Salih Z.; Walasik, Wiktor; Litchinitser, Natalia M.

    2016-05-01

    One of the most fundamental properties of isotropic negative-index metamaterials (NIMs), namely opposite directionality of the Poynting vector and the wavevector, enable many novel linear and nonlinear regimes of light–matter interactions. Here, we predict distinct characteristics of azimuthal modulation instability (MI) of optical vortices with different topological charges in NIMs with Kerr-type and saturable nonlinearity. We derive an analytical expression for the spatial modulation-instability gain for the Kerr-nonlinearity case and show that a specific condition relating the diffraction and the nonlinear lengths must be fulfilled for the azimuthal MI to occur. Finally, we investigate the rotation of the necklace beams due to the transfer of orbital angular momentum of the generating vortex on the movement of solitary necklace beams. We show that the direction of rotation is opposite in positive- and negative-index materials.

  8. Compound semiconductor bulk materials and characterizations, v.2

    CERN Document Server

    Oda, Osamu

    2012-01-01

    This book is concerned with compound semiconductor bulk materials, and has been written for students, researchers and engineers in material science and device fabrication. It provides the elementary and intermediate knowledge of compound semiconductor bulk materials necessary for entry into this field. The first volume described the physical properties, crystal growth technologies, principles of crystal growth, various defects in crystals, characterization techniques and applications, and reviewed various III-V and II-V compound semiconductor materials. In this second volume, other materials a

  9. Carbon nanotubes grown on bulk materials and methods for fabrication

    Science.gov (United States)

    Menchhofer, Paul A.; Montgomery, Frederick C.; Baker, Frederick S.

    2011-11-08

    Disclosed are structures formed as bulk support media having carbon nanotubes formed therewith. The bulk support media may comprise fibers or particles and the fibers or particles may be formed from such materials as quartz, carbon, or activated carbon. Metal catalyst species are formed adjacent the surfaces of the bulk support material, and carbon nanotubes are grown adjacent the surfaces of the metal catalyst species. Methods employ metal salt solutions that may comprise iron salts such as iron chloride, aluminum salts such as aluminum chloride, or nickel salts such as nickel chloride. Carbon nanotubes may be separated from the carbon-based bulk support media and the metal catalyst species by using concentrated acids to oxidize the carbon-based bulk support media and the metal catalyst species.

  10. Bulk sound velocity of porous materials at high pressures

    Institute of Scientific and Technical Information of China (English)

    耿华运; 吴强; 谭华; 蔡灵仓; 经福谦

    2002-01-01

    A correction of Walsh's method for bulk sound velocity calculation for shocked porous materials is accomplishedbased on the Wu-Jing thermodynamic equation of state. The corrected bulk velocities for solid and porous sampleswith low porosities are in good agreement with the corresponding experimental data published previously. On the basisof this corrected equation, the influence of thermoelectrons on the bulk velocity of shocked materials is discussed indetail at pressures of 50, 70 and 200 GPa. Some interesting phenomena are revealed, which seem to be the uniquefeatures of a dynamic-pressure-loading process and could not be found in static experiments.

  11. Fabrication of Bulk Nanocrystalline Ceramic Materials

    Czech Academy of Sciences Publication Activity Database

    Chráska, Tomáš; Neufuss, Karel; Dubský, Jiří; Ctibor, Pavel; Klementová, Mariana

    2008-01-01

    Roč. 17, 5-6 (2008), s. 872-877. ISSN 1059-9630 R&D Projects: GA AV ČR KAN300430651 Institutional research plan: CEZ:AV0Z20430508; CEZ:AV0Z40320502 Keywords : thermal spraying * nanocrystalline composites * wear Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.200, year: 2008

  12. Control over magnetic properties in bulk hybrid materials

    Science.gov (United States)

    Urban, Christian; Quesada, Adrian; Saerbeck, Thomas; Rubia, Miguel Angel De La; Garcia, Miguel Angel; Fernandez, Jose Francisco; Schuller, Ivan K.; UCSD Collaboration; Instituto de Ceramica, Madrid Collaboration; Institut Laue-Langevin, Grenoble Collaboration

    We present control of coercivity and remanent magnetization of a bulk ferromagnetic material embedded in bulk vanadium sesquioxide (V2O3) by using a standard bulk synthesis procedure. The method generalizes the use of structural phase transitions of one material to control structural and magnetic properties of another. A structural phase transition (SPT) in the V2O3 host material causes magnetic properties of Ni to change as function of temperature. The remanent magnetization and the coercivity are reversibly controlled by the SPT without additional external magnetic fields. The reversible tuning shown here opens the pathway for controlling the properties of a vast variety of magnetic hybrid bulk systems. This Work is supported by the Office of Basic Energy Science, U.S. Department of Energy, BES-DMS funded by the Department of Energy's Office of Basic Energy Science, DMR under grant DE FG02 87ER-45332.

  13. BULK NANOCRYSTALLINE ALUMINA-ZIRCONIA MATERIALS

    Czech Academy of Sciences Publication Activity Database

    Chráska, Tomáš; Klementová, Mariana

    České Budějovice : Czechoslovak microscopy society, 2007 - (Nebesářová, J.; Hozák, P.), s. 141-142 ISBN 978-80-239-9397-4. [Multinational Congress on Microscopy (8MCM)/8th./. Prague (CZ), 17.06.2007-21.06.2007] R&D Projects: GA AV ČR KAN300430651 Institutional research plan: CEZ:AV0Z20430508; CEZ:AV0Z40320502 Keywords : nanocrystalline ceramics * heat treatment * electron microscopy Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass

  14. Growth and characterization of bulk superconductor material

    CERN Document Server

    Chen, Dapeng; Maljuk, Andrey; Zhou, Fang

    2016-01-01

    This book focuses on recently developed crystal growth techniques to grow large and high quality superconducting single crystals. The techniques applied are traveling solvent floating zone (TSFZ) with infrared image furnace, Bridgeman, solution/flux and top seeded solution growth (TSSG) methods. The materials range from cuprates, cobaltates to pnictides including La2CuO4-based (LCO), YBa2Cu3O7-d (YBCO), Bi2Sr2Can−1CunO2n+4+δ (n=1,2,3) (BSCCO) to NaxCoO2. The modified Bridgman “cold finger” method is devoted to the pnictide system with the best quality (transition width DTc~0.5 K) with highest Tc~38.5 K of Ba0.68K0.32Fe2A2. The book presents various iron-based superconductors with different structures, such as 1111, 122, 111, 11 and 42622,10-3-8. Detailed single crystal growth methods (fluxes, Bridgman, floating zone), the associated procedures and their impact to crystal size and quality are presented. The book also describes the influence of doping on the structure and the electric, magnetic, and supe...

  15. New melt textured YBaCuO bulk material

    International Nuclear Information System (INIS)

    To understand the limiting factors of the critical current density Jc and to improve material parameters for bulk application we have been studied the microstructure and the magnetisation-levitation properties of a melt textured YBaCuO material prepared by an unidirectional melt solidification Ceramo-Crystal Growth (CCG) process. (orig.)

  16. Bulk material engineering and procurement management of NPS

    International Nuclear Information System (INIS)

    In a nuclear power project, bulk material is often not in an outstanding position, compared to equipment, yet bulk material is one of most difficult part in engineering and procurement management. If the schedule is not in good control, it will seriously hamper the progress of the whole project. The article explores bulk material engineering and procurement management of NPS, illustrated with tables and graphs. First, major difficult aspects of bulk material procurement are described. On one hand, bulk material is really bulky in kind. We must have detail information of manufacturers, manufacture duration, and take good control of bidding schedule. On the other hand, when an order is placed, we need to make clear everything in the procurement package, such as material types, delivery batches, quantity of each batch and delivery schedule, which is a tremendous work. Then, a schedule conflict is analyzed: when an order is placed, the detail type and quantity cannot be defined (since the construction design is not finished yet). To settle this conflict, the concept 'Requirement Schedule Curve' is brought forward, along with the calculation method. To get this curve, we need to make use of the technical data of the reference power station, along with the site construction schedule, to produce a site quantity requirement curve varying from time, for each type of material. Last, based on the 'Requirement Schedule Curve', we are able to build a unified database to control the engineering, procurement, manufacturing and delivery schedule, so as to procure precisely, manufacture on time, and optimize the storage. In this way, the accurate control of bulk material engineering and procurement schedule can be achieved. (authors)

  17. Negative Index Refraction in the Complex Ginzburg—Landau Equation in Connection with the Experimental CIMA Reaction

    International Nuclear Information System (INIS)

    In comparison with the phenomenon of negative index refraction observed in artificial meta-materials, it is interesting to ask if this type of behavior also exists or not in reaction-diffusion systems that support nonlinear chemical waves. Previous studies indicate that the negative index refraction could occur on a interface between a medium of a normal wave and a medium that supports anti-waves. Here we investigate the phenomenon in the complex Ginzburg—Landau equation (CGLE) in a close relationship with the quantitative model for the chloriteiodide-malonic acid (CIMA) reaction. The amplitude equation CGLE is deduced from the CIMA reaction, and simulations with mapped parameters from the reaction-diffusion equation reveal that the competition between normal waves and anti-waves on the interface determines whether the negative index refraction occurs or not

  18. Epitaxially Grown Layered MFI–Bulk MFI Hybrid Zeolitic Materials

    KAUST Repository

    Kim, Wun-gwi

    2012-11-27

    The synthesis of hybrid zeolitic materials with complex micropore-mesopore structures and morphologies is an expanding area of recent interest for a number of applications. Here we report a new type of hybrid zeolite material, composed of a layered zeolite material grown epitaxially on the surface of a bulk zeolite material. Specifically, layered (2-D) MFI sheets were grown on the surface of bulk MFI crystals of different sizes (300 nm and 10 μm), thereby resulting in a hybrid material containing a unique morphology of interconnected micropores (∼0.55 nm) and mesopores (∼3 nm). The structure and morphology of this material, referred to as a "bulk MFI-layered MFI" (BMLM) material, was elucidated by a combination of XRD, TEM, HRTEM, SEM, TGA, and N2 physisorption techniques. It is conclusively shown that epitaxial growth of the 2-D layered MFI sheets occurs in at least two principal crystallographic directions of the bulk MFI crystal and possibly in the third direction as well. The BMLM material combines the properties of bulk MFI (micropore network and mechanical support) and 2-D layered MFI (large surface roughness, external surface area, and mesoporosity). As an example of the uses of the BMLM material, it was incorporated into a polyimide and fabricated into a composite membrane with enhanced permeability for CO2 and good CO2/CH4 selectivity for gas separations. SEM-EDX imaging and composition analysis showed that the polyimide and the BMLM interpenetrate into each other, thereby forming a well-adhered polymer/particle microstructure, in contrast with the defective interfacial microstructure obtained using bare MFI particles. Analysis of the gas permeation data with the modified Maxwell model also allows the estimation of the effective volume of the BMLM particles, as well as the CO2 and CH4 gas permeabilities of the interpenetrated layer at the BMLM/polyimide interface. © 2012 American Chemical Society.

  19. Characterisation of ferroelectric bulk materials and thin films

    CERN Document Server

    Cain, Markys G

    2014-01-01

    This book presents a comprehensive review of the most important methods used in the characterisation of piezoelectric, ferroelectric and pyroelectric materials. It covers techniques for the analysis of bulk materials and thick and thin film materials and devices. There is a growing demand by industry to adapt and integrate piezoelectric materials into ever smaller devices and structures. Such applications development requires the joint development of reliable, robust, accurate and - most importantly - relevant and applicable measurement and characterisation methods and models. In the past f

  20. A single-layer wide-angle negative-index metamaterial at visible freque

    Energy Technology Data Exchange (ETDEWEB)

    Burgos, Stanley P. [California Inst. of Technology (CalTech), Pasadena, CA (United States); de Waele, Rene [FOM Inst. AMOLF, Amersterdam (Netherlands); Polman, Albert [FOM Inst. AMOLF, Amersterdam (Netherlands); Atwater, Harry A. [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    2010-04-18

    Metamaterials are materials with artificial electromagnetic properties defined by their sub-wavelength structure rather than their chemical composition. Negative-index materials (NIMs) are a special class of metamaterials characterized by an effective negative index that gives rise to such unusual wave behaviour as backwards phase propagation and negative refraction. These extraordinary properties lead to many interesting functions such as sub-diffraction imaging and invisibility cloaking. So far, NIMs have been realized through layering of resonant structures, such as split-ring resonators, and have been demonstrated at microwave to infrared frequencies over a narrow range of angles-of-incidence and polarization. However, resonant-element NIM designs suffer from the limitations of not being scalable to operate at visible frequencies because of intrinsic fabrication limitations, require multiple functional layers to achieve strong scattering and have refractive indices that are highly dependent on angle of incidence and polarization. Here we report a metamaterial composed of a single layer of coupled plasmonic coaxial waveguides that exhibits an effective refractive index of -2 in the blue spectral region with a figure-of-merit larger than 8. The resulting NIM refractive index is insensitive to both polarization and angle-of-incidence over a ±50° angular range, yielding a wide-angle NIM at visible frequencies.

  1. Accurate theoretical prediction on positron lifetime of bulk materials

    CERN Document Server

    Zhang, Wenshuai; Liu, Jiandang; Ye, Bangjiao

    2015-01-01

    Based on the first-principles calculations, we perform an initiatory statistical assessment on the reliability level of theoretical positron lifetime of bulk material. We found the original generalized gradient approximation (GGA) form of the enhancement factor and correlation potentials overestimates the effect of the gradient factor. Furthermore, an excellent agreement between model and data with the difference being the noise level of the data is found in this work. In addition, we suggest a new GGA form of the correlation scheme which gives the best performance. This work demonstrates that a brand-new reliability level is achieved for the theoretical prediction on positron lifetime of bulk material and the accuracy of the best theoretical scheme can be independent on the type of materials.

  2. Femtosecond micromachining in transparent bulk materials using an anamorphic lens.

    Science.gov (United States)

    Desautels, G Logan; Brewer, Chris D; Walker, Mark A; Juhl, Shane B; Finet, Marc A; Powers, Peter E

    2007-10-01

    A unique anamorphic lens design was applied to a circular 780nm femtosecond laser pulse to transform it into an elliptically shaped beam at focus. This lens was developed to give an alternative method of micromachining bulk transparent materials. The challenge for femtosecond laser processing is to control the nonlinear affect of self-focusing, which can occur when using a fast f-number lens. Once the focused spot is dominated by self-focusing the predicted focused beam becomes a filament inside the bulk, which is an undesirable effect. The anamorphic lens resolves this self-focusing by increasing the numerical aperture (NA) and employing an elliptical beam shape. The anamorphic lens was designed to furnish a 2.5mum by 190mum line at focus. Provided the pulse energy is high enough, transparent bulk material will be damaged with a single femtosecond laser pulse. Damage in this text refers to visual change in the index of refraction as observed under an optical microscope. Using this elliptical shape (or line), grating structures were micro-machined on the surface of SiC bulk transparent substrate. SiC was chosen because it is known for its micromachining difficulty and its crystalline structure. From the lack of self-focusing and using energy that is just above the damage threshold the focused line beam generated from the anamorphic lens grating structures produced a line shape nearly identical to the geometrical approximation. In this paper we discuss a new method of writing gratings (or other types of structures) in bulk transparent materials using a single femtosecond laser pulse. We will investigate the grating structures visually (inspected under an optical microscope) and also by use of an atomic force microscopy (AFM). In addition, we test the grating diffraction efficiency (DE) as a function of grating spacing, d. PMID:19550582

  3. Bulk Material Based Thermoelectric Energy Harvesting for Wireless Sensor Applications

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W S; Magnin, W; Wang, N; Hayes, M; O' Flynn, B; O' Mathuna, C, E-mail: wensi.wang@tyndall.ie [Tyndall National Institute, Dyke Parade, Cork (Ireland)

    2011-08-17

    The trend towards smart building and modern manufacturing demands ubiquitous sensing in the foreseeable future. Self-powered Wireless sensor networks (WSNs) are essential for such applications. This paper describes bulk material based thermoelectric generator (TEG) design and implementation for WSN. A 20cm{sup 2} Bi{sub 0.5}Sb{sub 1.5}Te{sub 3} based TEG was created with optimized configuration and generates 2.7mW in typical condition. A novel load matching method is used to maximize the power output. The implemented power management module delivers 651{mu}W to WSN in 50 deg. C. With average power consumption of Tyndall WSN measured at 72{mu}W, feasibility of utilizing bulk material TEG to power WSN is demonstrated.

  4. Bulk Laser Material Modification: Towards a Kerfless Laser Wafering Process

    Science.gov (United States)

    LeBeau, James

    Due to the ever increasing relevance of finer machining control as well as necessary reduction in material waste by large area semiconductor device manufacturers, a novel bulk laser machining method was investigated. Because the cost of silicon and sapphire substrates are limiting to the reduction in cost of devices in both the light emitting diode (LED) and solar industries, and the present substrate wafering process results in >50% waste, the need for an improved ingot wafering technique exists. The focus of this work is the design and understanding of a novel semiconductor wafering technique that utilizes the nonlinear absorption properties of band-gapped materials to achieve bulk (subsurface) morphological changes in matter using highly focused laser light. A method and tool was designed and developed to form controlled damage regions in the bulk of a crystalline sapphire wafer leaving the surfaces unaltered. The controllability of the subsurface damage geometry was investigated, and the effect of numerical aperture of the focusing optic, energy per pulse, wavelength, and number of pulses was characterized for a nanosecond pulse length variable wavelength Nd:YAG OPO laser. A novel model was developed to describe the geometry of laser induced morphological changes in the bulk of semiconducting materials for nanosecond pulse lengths. The beam propagation aspect of the model was based on ray-optics, and the full Keldysh multiphoton photoionization theory in conjuncture with Thornber's and Drude's models for impact ionization were used to describe high fluence laser light absorption and carrier generation ultimately resulting in permanent material modification though strong electron-plasma absorption and plasma melting. Although the electron-plasma description of laser damage formation is usually reserved for extremely short laser pulses (precision stage control.

  5. High coupling materials for thin film bulk acoustic wave resonators

    OpenAIRE

    Conde, Janine

    2009-01-01

    Radio frequency (RF) filters based on bulk acoustic wave resonances in piezoelectric thin films have become indispensable components in mobile communications. The currently used material, AlN, exhibits many excellent properties for this purpose. However, its bandwidth is often a limiting factor. In addition, no tuning is possible with AlN. Ferroelectrics would offer both larger coupling to achieve larger bandwidths, and tunability. However, their acoustic properties are not well known, especi...

  6. Thermal rectification in bulk materials with asymmetric shape

    OpenAIRE

    Sawaki, D.; Kobayashi, W.; Moritomo, Y.; Terasaki, I.

    2011-01-01

    We investigate thermal rectification in a bulk material with a pyramid shape to elucidate shape dependence of the thermal rectification, and find that rectifying coefficient R is 1.35 for this shape, which is smaller than R=1.43 for a rectangular shape. This result is fully duplicated by our numerical calculation based on Fourier's law. We also apply this calculation to a given shape, and show a possible way to increase R depending on the shape.

  7. Positron methods for the study of defects in bulk materials

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard

    The basic principles of positron annihilation physics are briefly discussed and the three most important experimental techniques used for bulk studies are described (i.e. positron lifetime, angular correlation, Doppler broadening). Several examples of the use of the positron methods are discussed...... for metals, ceramics and molecular materials, which illustrate the sensitivity of the positron annihilation techniques to vacancy type defects. For example it is shown how information can be obtained about vacancy formation energies, vacancy migration and clustering, vacancy-impurity interactions......, densities of rare gasses in bubbles in metals, and about free volume in molecular materials....

  8. Negative index of refraction in a four-level system with magnetoelectric cross coupling and local field corrections

    International Nuclear Information System (INIS)

    This research focuses on a coherently driven four-level atomic medium with the aim of inducing a negative index of refraction while taking into consideration local field corrections as well as magnetoelectric cross coupling (i.e.,chirality) within the material's response functions. Two control fields are used to render the medium transparent for a probe field which simultaneously couples to an electric and a magnetic dipole transition, thus allowing one to test the permittivity and permeability of the material at the same time. Numerical simulations show that a negative index of refraction with low absorption can be obtained for a range of probe detunings while depending on number density and the ratio between the intensities of the control fields.

  9. Software Progress in the PGNAA of Bulk Materials

    International Nuclear Information System (INIS)

    One of the primary evolving important uses of 252Cf sources is in the prompt gamma-ray neutron activation analysis (PGNAA) of the bulk materials in on-line continuous processes such as those for coal and cement. The advantages of this measurement approach for these applications are as follows: (a) it is noncontacting, (b) it is nondestructive, and (c) it is sensitive to large sample volumes. This paper describes the authors' work on the development of suitable computer software for this application

  10. Software Progress in the PGNAA of Bulk Materials

    Energy Technology Data Exchange (ETDEWEB)

    R. P. Gardner; C. W. Mayo; E. S. El Sayyed; W. Zhang

    2000-06-04

    One of the primary evolving important uses of {sup 252}Cf sources is in the prompt gamma-ray neutron activation analysis (PGNAA) of the bulk materials in on-line continuous processes such as those for coal and cement. The advantages of this measurement approach for these applications are as follows: (a) it is noncontacting, (b) it is nondestructive, and (c) it is sensitive to large sample volumes. This paper describes the authors' work on the development of suitable computer software for this application.

  11. Low-loss negative index metamaterials for X, Ku, and K microwave bands

    International Nuclear Information System (INIS)

    Low-loss, negative-index of refraction metamaterials were designed and tested for X, Ku, and K microwave frequency bands. An S-shaped, split-ring resonator was used as a unit cell to design homogeneous slabs of negative-index metamaterials. Then, the slabs of metamaterials were cut unto prisms to measure experimentally the negative index of refraction of a plane electromagnetic wave. Theoretical simulations using High-Frequency Structural Simulator, a finite element equation solver, were in good agreement with experimental measurements. The negative index of refraction was retrieved from the angle- and frequency-dependence of the transmitted intensity of the microwave beam through the metamaterial prism and compared well to simulations; in addition, near-field electromagnetic intensity mapping was conducted with an infrared camera, and there was also a good match with the simulations for expected frequency ranges for the negative index of refraction

  12. Effect of rare earth substitution in cobalt ferrite bulk materials

    Science.gov (United States)

    Bulai, G.; Diamandescu, L.; Dumitru, I.; Gurlui, S.; Feder, M.; Caltun, O. F.

    2015-09-01

    The study was focused on the influence of small amounts of rare earth (RE=La, Ce, Sm, Gd, Dy, Ho, Er, Yb) addition on the microstructure, phase content and magnetic properties of cobalt ferrite bulk materials. The X-Ray diffraction measurements confirmed the formation of the spinel structure but also the presence of secondary phases of RE oxides or orthoferrite in small percentages (up to 3%). Density measurements obtained by Archimedes method revealed a ~1 g cm-3 decrease for the RE doped cobalt ferrite samples compared with stoichiometric one. Both the Mössbauer and Fourier Transform Infrared Spectrocopy analysis results confirmed the formation of the spinel phase. The saturation magnetization and coercive field values of the doped samples obtained by Vibrating Sample Magnetometry were close to those of the pure cobalt ferrite. For magnetostrictive property studies the samples were analyzed using the strain gauge method. Higher maximum magnetostriction coefficients were found for the Ho, Ce, Sm and Yb doped cobalt ferrite bulk materials as related to the stoichiometric CoFe2O4 sample. Moreover, improved strain derivative was observed for these samples but at higher magnetic fields due to the low increase of the coercive field values for doped samples.

  13. Effect of rare earth substitution in cobalt ferrite bulk materials

    International Nuclear Information System (INIS)

    The study was focused on the influence of small amounts of rare earth (RE=La, Ce, Sm, Gd, Dy, Ho, Er, Yb) addition on the microstructure, phase content and magnetic properties of cobalt ferrite bulk materials. The X-Ray diffraction measurements confirmed the formation of the spinel structure but also the presence of secondary phases of RE oxides or orthoferrite in small percentages (up to 3%). Density measurements obtained by Archimedes method revealed a ~1 g cm−3 decrease for the RE doped cobalt ferrite samples compared with stoichiometric one. Both the Mössbauer and Fourier Transform Infrared Spectrocopy analysis results confirmed the formation of the spinel phase. The saturation magnetization and coercive field values of the doped samples obtained by Vibrating Sample Magnetometry were close to those of the pure cobalt ferrite. For magnetostrictive property studies the samples were analyzed using the strain gauge method. Higher maximum magnetostriction coefficients were found for the Ho, Ce, Sm and Yb doped cobalt ferrite bulk materials as related to the stoichiometric CoFe2O4 sample. Moreover, improved strain derivative was observed for these samples but at higher magnetic fields due to the low increase of the coercive field values for doped samples. - Highlights: • Substitution by a large number of rare earth elements was investigated. • First reported results on magnetostriction measurements of RE doped cobalt ferrite. • The doped samples presented an increased porosity and a decreased grain size. • Increased magnetostrctive response was observed for several doped samples

  14. Surface, interface and bulk materials characterization using Indus synchrotron sources

    International Nuclear Information System (INIS)

    Synchrotron radiation sources, providing intense, polarized and stable beams of ultra violet, soft and hard x-ray photons, are having great impact on physics, chemistry, biology, materials science and other areas research. In particular synchrotron radiation has revolutionized materials characterization techniques by enhancing its capabilities for investigating the structural, electronic and magnetic properties of solids. The availability of synchrotron sources and necessary instrumentation has led to considerable improvements in spectral resolution and intensities. As a result, application scope of different materials characterization techniques has tremendously increased particularly in the analysis of solid surfaces, interfaces and bulk materials. The Indian synchrotron storage ring, Indus-1 and Indus-2 are in operation at RRCAT, Indore. The UGC-DAE CSR with the help of university scientist had designed and developed an angle integrated photoelectron spectroscopy (AlPES) beam line on Indus-1 storage ring of 450 MeV and polarized light beam line for soft x-ray absorption spectroscopy (SXAS) on Indus-2 storage ring of 2.5 GeV. (author)

  15. Effect of rare earth substitution in cobalt ferrite bulk materials

    Energy Technology Data Exchange (ETDEWEB)

    Bulai, G., E-mail: georgiana.bulai@uaic.ro [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bd. Carol I, nr. 11, 700506 Iasi (Romania); Diamandescu, L. [National Institute of Material Physics, P.O. Box MG-7, 07125 Bucharest (Romania); Dumitru, I.; Gurlui, S. [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bd. Carol I, nr. 11, 700506 Iasi (Romania); Feder, M. [National Institute of Material Physics, P.O. Box MG-7, 07125 Bucharest (Romania); Caltun, O.F. [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Bd. Carol I, nr. 11, 700506 Iasi (Romania)

    2015-09-15

    The study was focused on the influence of small amounts of rare earth (RE=La, Ce, Sm, Gd, Dy, Ho, Er, Yb) addition on the microstructure, phase content and magnetic properties of cobalt ferrite bulk materials. The X-Ray diffraction measurements confirmed the formation of the spinel structure but also the presence of secondary phases of RE oxides or orthoferrite in small percentages (up to 3%). Density measurements obtained by Archimedes method revealed a ~1 g cm{sup −3} decrease for the RE doped cobalt ferrite samples compared with stoichiometric one. Both the Mössbauer and Fourier Transform Infrared Spectrocopy analysis results confirmed the formation of the spinel phase. The saturation magnetization and coercive field values of the doped samples obtained by Vibrating Sample Magnetometry were close to those of the pure cobalt ferrite. For magnetostrictive property studies the samples were analyzed using the strain gauge method. Higher maximum magnetostriction coefficients were found for the Ho, Ce, Sm and Yb doped cobalt ferrite bulk materials as related to the stoichiometric CoFe{sub 2}O{sub 4} sample. Moreover, improved strain derivative was observed for these samples but at higher magnetic fields due to the low increase of the coercive field values for doped samples. - Highlights: • Substitution by a large number of rare earth elements was investigated. • First reported results on magnetostriction measurements of RE doped cobalt ferrite. • The doped samples presented an increased porosity and a decreased grain size. • Increased magnetostrctive response was observed for several doped samples.

  16. Basics of averaging of the Maxwell equations for bulk materials

    CERN Document Server

    Chipouline, A; Tretyakov, S

    2012-01-01

    Volume or statistical averaging of the microscopic Maxwell equations (MEs), i.e. transition from microscopic MEs to their macroscopic counterparts, is one of the main steps in electrodynamics of materials. In spite of the fundamental importance of the averaging procedure, it is quite rarely properly discussed in university courses and respective books; up to now there is no established consensus about how the averaging procedure has to be performed. In this paper we show that there are some basic principles for the averaging procedure (irrespective to what type of material is studied) which have to be satisfied. Any homogenization model has to be consistent with the basic principles. In case of absence of this correlation of a particular model with the basic principles the model could not be accepted as a credible one. Another goal of this paper is to establish the averaging procedure for bulk MM, which is rather close to the case of compound materials but should include magnetic response of the inclusions an...

  17. Bulk Density Adjustment of Resin-Based Equivalent Material for Geomechanical Model Test

    OpenAIRE

    Pengxian Fan; Haozhe Xing; Linjian Ma; Kaifeng Jiang; Mingyang Wang; Zechen Yan; Xiang Fang

    2015-01-01

    An equivalent material is of significance to the simulation of prototype rock in geomechanical model test. Researchers attempt to ensure that the bulk density of equivalent material is equal to that of prototype rock. In this work, barite sand was used to increase the bulk density of a resin-based equivalent material. The variation law of the bulk density was revealed in the simulation of a prototype rock of a different bulk density. Over 300 specimens were made for uniaxial compression test....

  18. High-throughput Z T predictions of nanoporous bulk materials as next-generation thermoelectric materials: A material genome approach

    Science.gov (United States)

    Hao, Qing; Xu, Dongchao; Lu, Na; Zhao, Hongbo

    2016-05-01

    The advancement of computational tools for material property predictions enables a broad search of novel materials for various energy-related applications. However, challenges still exist in accurately predicting the mean free paths of electrons and phonons in a high-throughput frame for thermoelectric property predictions, which largely hinders the computation-driven material search for novel materials. In this work, this need is eliminated under the limit of reduced nanostructure size within a bulk material, in which these mean free paths are restricted by the nanostructure size. A criterion for Z T evaluation is proposed for general nanoporous bulk materials and is demonstrated with representative oxides.

  19. Bulk metallic glasses: A new class of engineering materials

    Indian Academy of Sciences (India)

    Joysurya Basu; S Ranganathan

    2003-06-01

    Bulk glass-forming alloys have emerged over the past fifteen years with attractive properties and technological promise. A number of alloy systems based on lanthanum, magnesium, zirconium, palladium, iron, cobalt and nickel have been discovered. Glass-forming ability depends on various factors like enthalpy of mixing, atomic size and multicomponent alloying. A number of processes is available to synthesise bulk metallic glasses. The crystallisation behaviour and mechanical properties of these alloys pose interesting scientific questions. Upon crystallisation many of these glasses transform to bulk nanocrystals and nanoquasicrystals. A detailed study of the structure and the crystallisation behaviour of glasses has enabled the elucidation of the possible atomic configuration in liquid alloys. Their crystallisation behaviour can be exploited to synthesise novel nanocomposite microstructures and their mechanical properties can be enhanced. A broad overview of the present status of the science and technology of bulk metallic glasses and their potential technological uses is presented.

  20. Nanoengineering of a Negative-Index Binary-Staircase Lens for the Optics Regime

    CERN Document Server

    Casse, B D F; Lu, W T; Huang, Y J; Selvarasah, S; Dokmeci, M; Sridhar, S

    2008-01-01

    We show that a binary-staircase optical element can be engineered to exhibit an effective negative index of refraction, thereby expanding the range of optical properties theoretically available for future optoelectronic devices. The mechanism for achieving a negative-index lens is based on exploiting the periodicity of the surface corrugation. By designing and nanofabricating a plano-concave binary-staircase lens in the InP/InGaAsP platform, we have experimentally demonstrated at 1.55 microns that such negative-index concave lenses can focus plane waves. The beam propagation in the lens was studied experimentally and was in excellent agreement with the three-dimensional finite-difference time-domain numerical simulations.

  1. Software progress in the PGNAA of bulk materials

    International Nuclear Information System (INIS)

    One of the primary evolving important uses of 252Cf sources is in the prompt gamma-ray neutron activation analysis (PGNAA) of the bulk material in on-line continuous processes such as those for coal and cement. The advantages of this measurement approach for these applications are as follows: (a) it is noncontacting, (b) it is nondestructive, and (c) it is sensitive to large sample volumes. The authors have been working on the development of suitable computer software for this application. Their primary approach has been the Monte Carlo Library Least-Squares method, in which library spectra for each element are calculated with the specific-purpose Monte Carlo code CEARPGA. These libraries are then used with experimental spectra in a standard library least-squares (LLS) approach to determine elemental amounts. Since the PGNAA response is nonlinear for these applications, one must first make an initial estimate of the sample composition. If the final calculated elemental amounts are not close enough to the initial estimate that linearity can be assumed, another iteration with a better estimate of the sample composition must be made. One of the general problems encountered in analyses of this type is the spectrum distortion introduced by the pulse pileup that occurs with light counting rates. In many applications, one desires the highest possible counting rate so that fast transient phenomena can be accurately followed. The technique of using electronic discrimination is only partially successful in that one throws away much of the data and there is some remaining distortion in the data that are kept. For this reason they developed a Monte Carlo model for the forward simulation of pulse pileup (given the true counting rate the pulse piled-up distorted spectrum is generated). The resulting computer code can give an accurate spectral result in 2 or 3 min on present personal computers. This result can either be used directly to generate model spectra that can be compared

  2. Software progress in the PGNAA of bulk materials

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, R.P.; Mayo, C.W.; El Sayyed, E.S.; Zhang, W.

    2000-07-01

    One of the primary evolving important uses of {sup 252}Cf sources is in the prompt gamma-ray neutron activation analysis (PGNAA) of the bulk material in on-line continuous processes such as those for coal and cement. The advantages of this measurement approach for these applications are as follows: (a) it is noncontacting, (b) it is nondestructive, and (c) it is sensitive to large sample volumes. The authors have been working on the development of suitable computer software for this application. Their primary approach has been the Monte Carlo Library Least-Squares method, in which library spectra for each element are calculated with the specific-purpose Monte Carlo code CEARPGA. These libraries are then used with experimental spectra in a standard library least-squares (LLS) approach to determine elemental amounts. Since the PGNAA response is nonlinear for these applications, one must first make an initial estimate of the sample composition. If the final calculated elemental amounts are not close enough to the initial estimate that linearity can be assumed, another iteration with a better estimate of the sample composition must be made. One of the general problems encountered in analyses of this type is the spectrum distortion introduced by the pulse pileup that occurs with light counting rates. In many applications, one desires the highest possible counting rate so that fast transient phenomena can be accurately followed. The technique of using electronic discrimination is only partially successful in that one throws away much of the data and there is some remaining distortion in the data that are kept. For this reason they developed a Monte Carlo model for the forward simulation of pulse pileup (given the true counting rate the pulse piled-up distorted spectrum is generated). The resulting computer code can give an accurate spectral result in 2 or 3 min on present personal computers. This result can either be used directly to generate model spectra that can be

  3. Negative index of refraction, perfect lenses and transformation optics -- some words of caution

    CERN Document Server

    Bergamin, Luzi

    2010-01-01

    In this paper we show that a negative index of refraction is not a direct implication of transformation optics with orientation-reversing diffeomorphisms. Rather a negative index appears due to a specific choice of sign freedom. Furthermore, we point out that the transformation designed lens, which relies on the concept of spacetime folding, does not amplify evanescent modes, in contrast to the Pendry-Veselago lens. Instead, evanescent modes at the image point are produced by a duplicated source and thus no imaging of the near field (perfect lensing) takes place.

  4. Photonic band structure and effective medium properties of doubly-resonant core-shell metallo-dielectric nanowire arrays: low-loss, isotropic optical negative-index behavior

    International Nuclear Information System (INIS)

    We investigate theoretically and numerically the photonic band structure in the optical domain of an array of core–shell metal-semiconductor nanowires. Corresponding negative-index photonic bands are calculated, showing isotropic equifrequency surfaces. The effective (negative) electric permittivity and magnetic permeability, retrieved from S-parameters, are used to compare the performance of such nanowire arrays with homogeneous media in canonical examples, such as refraction through a prism and flat-lens focusing. Very good agreement is found, confirming the effective medium behavior of the nanowire array as a low-loss, isotropic (2D) and bulk, optical negative index metamaterial. Indeed, disorder is introduced to further stress its robustness. (paper)

  5. 9 CFR 113.10 - Testing of bulk material for export or for further manufacture.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Testing of bulk material for export or for further manufacture. 113.10 Section 113.10 Animals and Animal Products ANIMAL AND PLANT HEALTH... VECTORS STANDARD REQUIREMENTS Applicability § 113.10 Testing of bulk material for export or for...

  6. Advanced correlation functionals: Application to bulk materials and localized systems

    OpenAIRE

    García-González, P.; Fernández, J.J.; Marini, Andrea; Rubio Secades, Ángel

    2007-01-01

    Time-dependent density functional theory (TDDFT) is an efficient method to evaluate excited-state properties of electron systems. However, it is not so well-known that it also provides a very accurate prescription to obtain correlation energies by using the so-called adiabatic connection fluctuation dissipation theorem (ACFDT). In this paper we present a detailed study of the ACFDT performance in bulk solids and jellium clusters. These results confirm the reliability of the ACFDT scheme and p...

  7. Characterization of Zeolite in Zeolite-Geopolymer Hybrid Bulk Materials Derived from Kaolinitic Clays

    Directory of Open Access Journals (Sweden)

    Hayami Takeda

    2013-05-01

    Full Text Available Zeolite-geopolymer hybrid materials have been formed when kaolin was used as a starting material. Their characteristics are of interest because they can have a wide pore size distribution with micro- and meso-pores due to the zeolite and geopolymer, respectively. In this study, Zeolite-geopolymer hybrid bulk materials were fabricated using four kinds of kaolinitic clays (a halloysite and three kinds of kaolinite. The kaolinitic clays were first calcined at 700 °C for 3 h to transform into the amorphous aluminosilicate phases. Alkali-activation treatment of the metakaolin yielded bulk materials with different amounts and types of zeolite and different compressive strength. This study investigated the effects of the initial kaolinitic clays on the amount and types of zeolite in the resultant geopolymers as well as the strength of the bulk materials. The kaolinitic clays and their metakaolin were characterized by XRD analysis, chemical composition, crystallite size, 29Si and 27Al MAS NMR analysis, and specific surface area measurements. The correlation between the amount of zeolite formed and the compressive strength of the resultant hybrid bulk materials, previously reported by other researchers was not positively observed. In the studied systems, the effects of Si/Al and crystalline size were observed. When the atomic ratio of Si/Al in the starting kaolinitic clays increased, the compressive strength of the hybrid bulk materials increased. The crystallite size of the zeolite in the hybrid bulk materials increased with decreasing compressive strength of the hybrid bulk materials.

  8. Two-dimensional fluid-filled closed-cell cellular solid as an acoustic metamaterial with negative index

    Science.gov (United States)

    Dorodnitsyn, V.; Van Damme, B.

    2016-04-01

    A concept for acoustic metamaterials consisting of a cellular medium with fluid-filled cells is fabricated and studied experimentally. In such a system, the fluid and solid structure explicitly interact, and elastic wave propagation is coupled to both phases. Focusing here on shear wave behavior, we confirm previous numerical studies in three steps. We first measure the material deformations pertaining to three qualitatively different shear wave modes in the frequency range below 3.5 kHz. We then measure the group velocity and demonstrate that, within a certain frequency interval, the group and phase velocity have opposite signs. This shows that the system acts as a negative-index metamaterial. Finally, we confirm the presence of band gaps due to the locally resonant behavior of the cell walls. The demonstrated concept of a closed, fluid-filled cellular material as an acoustic metamaterial opens a wide space for applications.

  9. Bulk nanocrystalline alumina-zirconia materials prepared by plasma spraying

    Czech Academy of Sciences Publication Activity Database

    Chráska, Tomáš; Neufuss, Karel; Rohan, Pavel; Dubský, Jiří; Oberste-Berghaus, J.

    Seattle, USA : ASM International, Materials Park, OH, USA, 2006 - (Marple, B.; Moreau, C.), s. 186-187 ISBN 0-87170-809-4. [International Thermal Spray Conference, ITSC 2006. Seattle (US), 15.05.2006-18.05.2006] Institutional research plan: CEZ:AV0Z20430508 Keywords : nanocomposites * ceramics * abrasion resistance * plasma spraying Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass

  10. The choice of nuclear material measurement strategy in bulk-form in material balance area

    International Nuclear Information System (INIS)

    Concepts have been defined such as Shipment batch, Technological batch, and Accounting batch, it has been found that Shipment and Technological batches should be formed through the arrangement of group of measured Accounting batches. The strategy for nuclear material (NM) measurement based on the Accounting batch is shown to give a possibility to use the advantages for the accounting purposes: ensure safeguards of non-diversion of NM at quantitative (numerical) level, which is a higher grade of safeguards compared to the systems of accounting and control now in force of the US and EURATOM; ensure a guaranteed accuracy and reliability (confidence level) when making up NM balance in Material Balance Area (MBA) and at Federal level, which has been realized only in part in the NM control and accounting systems. Strategy of NM measurement for MBAs counting NM in bulk form has been proposed

  11. Specific absorption rate analysis of broadband mobile antenna with negative index metamaterial

    Science.gov (United States)

    Alam, Touhidul; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

    2016-03-01

    This paper presents a negative index metamaterial-inspired printed mobile wireless antenna that can support most mobile applications such as GSM, UMTS, Bluetooth and WLAN frequency bands. The antenna consists of a semi-circular patch, a 50Ω microstrip feed line and metamaterial ground plane. The antenna occupies a very small space of 37 × 47 × 0.508 mm3, making it suitable for mobile wireless application. The perceptible novelty shown in this proposed antenna is that reduction of specific absorption rate using the negative index metamaterial ground plane. The proposed antenna reduced 72.11 and 75.53 % of specific absorption rate at 1.8 and 2.4 GHz, respectively.

  12. Flat lenses constructed by graded negative index-based photonic crystals with tuned configurations

    International Nuclear Information System (INIS)

    Flat lenses are designed by means of graded negative refractive index-based photonic crystals (PCs) constructed using air-holes tuned with different shapes. By gradually modifying the filling factor along the transverse direction, we obtain the graded negative index-based lenses for the purpose of focusing an incident plane wave. The finite-difference and time-domain (FDTD) algorithm is adopted for numerical calculation. Our calculation results indicate that these lenses can finely focus incident plane waves. Moreover, for the same size of air-holes, the focusing properties of the lens with rectangular air-holes are better than those with the other shaped air-holes. The graded negative index PCs lenses could possibly enable new applications in optoelectronic systems. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  13. Measurements of Broadband Negative Index in Space-Coiling Acoustic Metamaterials

    OpenAIRE

    Xie, Yangbo; Popa, Bogdan-Ioan; Zigoneanu, Lucian; Cummer, Steven A.

    2012-01-01

    We report the experimental demonstration of broadband negative refractive index obtained in a labyrinthine acoustic metamaterial structure. Two different approaches were employed to prove the metamaterial negative index nature: one-dimensional extractions of effective parameters from reflection and transmission measurements, and two-dimensional prism-based measurements that convincingly show the transmission angle corresponding to negative refraction. The transmission angles observed in the l...

  14. The bulk modulus and Poisson's ratio of “incompressible” materials

    Science.gov (United States)

    Mott, P. H.; Dorgan, J. R.; Roland, C. M.

    2008-05-01

    Poisson's ratio, ν, is a fundamental parameter characterizing the mechanical behavior of a material. Because the ratio of the bulk to the shear modulus, B/G, becomes infinite when ν=1/2, it is often assumed that the bulk modulus becomes very large as a material approaches “incompressibility.” This is incorrect; experimental results for viscoelastic materials show that changes in the bulk modulus are actually negligible as ν approaches 1/2. An analysis is performed to clarify the apparent conflict between the classic elastic equations and the experiments. At ν=1/2, the bulk modulus is shown to exhibit a singularity, but this is irrelevant to real materials.

  15. Weighing and control of bulk material in ship-lading process at harbor

    International Nuclear Information System (INIS)

    The author describes a new weighing and control system for bulk material in ship-loading process at harbor. It adopts nuclear radiation measurement, computer control and digital signal process techniques to weigh the bulk material with no-touch with the advantages of stability and anti-jamming. The measure accuracy reaches to 0.5% - 1.0%. It is was applicable in the bad condition of ship-loading spot at harbor

  16. A robust, melting class bulk superhydrophobic material with heat-healing and self-cleaning properties

    OpenAIRE

    Ramakrishna, S; Santhosh Kumar, K. S.; Dona Mathew; Reghunadhan Nair, C. P.

    2015-01-01

    Superhydrophobic (SH) materials are essential for a myriad of applications such as anti-icing and self-cleaning due to their extreme water repellency. A single, robust material simultaneously possessing melt-coatability, bulk water repellency, self-cleanability, self-healability, self-refreshability, and adhesiveness has been remaining an elusive goal. We demonstrate a unique class of melt-processable, bulk SH coating by grafting long alkyl chains on silica nanoparticle surface by a facile on...

  17. Basics of averaging of the Maxwell equations for bulk materials

    OpenAIRE

    Chipouline, A.; Simovski, C.; Tretyakov, S.

    2012-01-01

    Volume or statistical averaging of the microscopic Maxwell equations (MEs), i.e. transition from microscopic MEs to their macroscopic counterparts, is one of the main steps in electrodynamics of materials. In spite of the fundamental importance of the averaging procedure, it is quite rarely properly discussed in university courses and respective books; up to now there is no established consensus about how the averaging procedure has to be performed. In this paper we show that there are some b...

  18. Ab initio electronic stopping power of protons in bulk materials

    Science.gov (United States)

    Shukri, Abdullah Atef; Bruneval, Fabien; Reining, Lucia

    2016-01-01

    The electronic stopping power is a crucial quantity for ion irradiation: it governs the deposited heat, the damage profile, and the implantation depth. Whereas experimental data are readily available for elemental solids, the data are much more scarce for compounds. Here we develop a fully ab initio computational scheme based on linear response time-dependent density-functional theory to predict the random electronic stopping power (RESP) of materials without any empirical fitting. We show that the calculated RESP compares well with experimental data, when at full convergence, with the inclusion of the core states and of the exchange correlation. We evaluate the unexpectedly limited magnitude of the nonlinear terms in the RESP by comparing with other approaches based on the time propagation of time-dependent density-functional theory. Finally, we check the validity of a few empirical rules of thumbs that are commonly used to estimate the electronic stopping power.

  19. Application of bulk material commodity code in nuclear engineering

    International Nuclear Information System (INIS)

    The text details the signification and current status and difficulty of commodity code in the nuclear power engineering. By the applying condition of Ling Ao Phrase 2 Nuclear Power Plant there are several ways to create commodity code. Detail how to make commodity code structure and commodity code rule. And define material style, commodity code prefix, size and thickness etc. Then create commodity code. The other way is by user define to create commodity code. Next register specification in VPRM, make size range, thickness and branch fitting consolidation in the specification, select commodity code to create part number. And introduce how the interface of VPRM and PDMS, how import the weight data, and how make owner part number press in the drawing conveniently. The part numbers are applied in the drawings of LingAo Phrase 2 Nuclear Power Plant, owner accepts them. (authors)

  20. Three-dimensional negative index of refraction at optical frequencies by coupling plasmonic waveguides.

    Science.gov (United States)

    Verhagen, Ewold; de Waele, René; Kuipers, L; Polman, Albert

    2010-11-26

    We identify a route towards achieving a negative index of refraction at optical frequencies based on coupling between plasmonic waveguides that support backwards waves. We show how modal symmetry can be exploited in metal-dielectric waveguide pairs to achieve negative refraction of both phase and energy. Control of waveguide coupling yields a metamaterial consisting of a one-dimensional multilayer stack that exhibits an isotropic index of -1 at a free-space wavelength of 400 nm. The concepts developed here may inspire new low-loss metamaterial designs operating close to the metal plasma frequency. PMID:21231386

  1. Three-dimensional negative index of refraction at optical frequencies by coupling plasmonic waveguides

    CERN Document Server

    Verhagen, Ewold; L.,; Kuipers,; Polman, Albert

    2010-01-01

    We identify a route towards achieving a negative index of refraction at optical frequencies based on coupling between plasmonic waveguides that support backwards waves. We show how modal symmetry can be exploited in metal-dielectric waveguide pairs to achieve negative refraction of both phase and energy. By properly controlling coupling between adjacent waveguides, a metamaterial consisting of a one-dimensional multilayer stack exhibiting an isotropic index of -1 can be achieved at a free-space wavelength of 400 nm. The general concepts developed here may inspire new low-loss metamaterial designs operating close to the metal plasma frequency.

  2. Three-Dimensional Negative Index of Refraction at Optical Frequencies by Coupling Plasmonic Waveguides

    Science.gov (United States)

    Verhagen, Ewold; de Waele, René; Kuipers, L.; Polman, Albert

    2010-11-01

    We identify a route towards achieving a negative index of refraction at optical frequencies based on coupling between plasmonic waveguides that support backwards waves. We show how modal symmetry can be exploited in metal-dielectric waveguide pairs to achieve negative refraction of both phase and energy. Control of waveguide coupling yields a metamaterial consisting of a one-dimensional multilayer stack that exhibits an isotropic index of -1 at a free-space wavelength of 400 nm. The concepts developed here may inspire new low-loss metamaterial designs operating close to the metal plasma frequency.

  3. Superhard MgB2 bulk material prepared by high-pressure sintering

    International Nuclear Information System (INIS)

    Superhard MgB2 bulk material with a golden metallic shine was synthesized by high-pressure sintering for 8 h at 5.5 GPa and different temperatures. Appropriate pressure and temperature conditions for synthesizing polycrystalline MgB2 with high hardness were investigated. The samples were characterized by means of atomic force microscopy and x-ray diffraction. The Vickers hardness, bulk density, and electrical resistivity were measured at room temperature

  4. Effects of negative index medium defect layers on the trans mission properties of one-dimensional photonic crystal

    Institute of Scientific and Technical Information of China (English)

    XIANG Yuan-jiang; DAI Xiao-yu; WEN Shuang-chun

    2007-01-01

    School of Computer and Communication, Hunan University, Changsha 410082, ChinaThe photonic band gap structure of 1D photonic crystal with a negative index medium defect layer is studied by using the transfer matrix method. Investigations show that the introdution of negative index medium defect layer and the increase of the negative index value will result in an extension of the band gap. Moreover, by increasing the negative index, the width of defect layer and the numbers of period photonic crystal, the width of defect modes will be narrowed, which is advantaged to obtain optical filters with narrow band. Finally, the effects of absorption on the properties of band gap and on defect modes have been discussed.

  5. Minimization of losses in a structure having a negative index of refraction

    International Nuclear Information System (INIS)

    A structure consisting of an array of wires cladded with a nonmagnetic dielectric and embedded in a ferrimagnetic host has been calculated to have a negative index of refraction. The structure has moderate losses over a bandwidth of a few GHz. The calculation takes into account the skin effect within the wires and is valid provided the wavelength of electromagnetic waves in the structure is long compared to the radius of the cladded wires. The structure's electromagnetic response is accurately described by the ferrimagnet's permeability and a permittivity derived in the long wavelength limit. Losses can be minimized by choosing the pass band to be between 30 and 80% of the plasma frequency and by choosing wires to be of the highest possible conductivity and largest radius compatible with the required plasma frequency

  6. Measurement of a broadband negative index with space-coiling acoustic metamaterials.

    Science.gov (United States)

    Xie, Yangbo; Popa, Bogdan-Ioan; Zigoneanu, Lucian; Cummer, Steven A

    2013-04-26

    We report the experimental demonstration of a broadband negative refractive index obtained in a labyrinthine acoustic metamaterial structure. Two different approaches were employed to prove the metamaterial negative index nature: one-dimensional extractions of effective parameters from reflection and transmission measurements and two-dimensional prism-based measurements that convincingly show the transmission angle corresponding to negative refraction. The transmission angles observed in the latter case also agree very well with the refractive index obtained in the one-dimensional measurements and numerical simulations. We expect this labyrinthine metamaterial to become the unit cell of choice for practical acoustic metamaterial devices that require broadband and significantly negative indices of refraction. PMID:23679743

  7. Materials preparation and magnetization of Gd-Ba-Cu-O bulk high-temperature superconductors

    Science.gov (United States)

    Ida, Tetsuya; Li, Zhi; Zhou, Difan; Miki, Motohiro; Zhang, Yufeng; Izumi, Mitsuru

    2016-05-01

    The paper reports on recent achievements in the preparation and magnetization of bulk high-temperature superconductors (HTS). The melt-growth of HTS bulks has technically stabilized due to the use of buffer materials with a seed crystal and modified infiltration to supply a rich liquid phase during growth. This modified growth technology was adapted as our standard processing method. This paper describes some new aspects of both field cooling and pulsed field magnetization processes. Pulsed field magnetization uses waveform control that feeds back the transient flux around the top-center of the bulks and traps a field of 1.63 T, which is more than 90% of the field cooling value. This was achieved by applying a single step pulsed field at a liquid nitrogen temperature. For practical applications, the magnetization under a static magnetic field that is tilted from the crystallographic c-axis was investigated at liquid nitrogen temperature. The trapped flux component perpendicular to the bulk surface remains strong up to θ = 30° inclination, compared to the procedure along the axis. Information about HTS bulks is considered to be important for machine applications using bulk HTS as cryo-permanent magnets.

  8. Advanced bulk processing of lightweight materials for utilization in the transportation sector

    Science.gov (United States)

    Milner, Justin L.

    The overall objective of this research is to develop the microstructure of metallic lightweight materials via multiple advanced processing techniques with potentials for industrial utilization on a large scale to meet the demands of the aerospace and automotive sectors. This work focused on (i) refining the grain structure to increase the strength, (ii) controlling the texture to increase formability and (iii) directly reducing processing/production cost of lightweight material components. Advanced processing is conducted on a bulk scale by several severe plastic deformation techniques including: accumulative roll bonding, isolated shear rolling and friction stir processing to achieve the multiple targets of this research. Development and validation of the processing techniques is achieved through wide-ranging experiments along with detailed mechanical and microstructural examination of the processed material. On a broad level, this research will make advancements in processing of bulk lightweight materials facilitating industrial-scale implementation. Where accumulative roll bonding and isolated shear rolling, currently feasible on an industrial scale, processes bulk sheet materials capable of replacing more expensive grades of alloys and enabling low-temperature and high-strain-rate formability. Furthermore, friction stir processing to manufacture lightweight tubes, made from magnesium alloys, has the potential to increase the utilization of these materials in the automotive and aerospace sectors for high strength - high formability applications. With the increased utilization of these advanced processing techniques will significantly reduce the cost associated with lightweight materials for many applications in the transportation sectors.

  9. A high energy microscope for local strain measurements within bulk materials

    DEFF Research Database (Denmark)

    Lienert, U.; Poulsen, H.F.; Martins, R.V.; Kvick, Å.

    A novel diffraction technique for local, three dimensional strain scanning within bulk materials is presented. The technique utilizes high energy, micro-focussed synchrotron radiation which can penetrate several millimeters into typical metals. The spatial resolution can be as narrow as 1 mum in...

  10. Shear-mediated contributions to the effective properties of soft acoustic metamaterials including negative index

    Science.gov (United States)

    Forrester, Derek Michael; Pinfield, Valerie J.

    2015-12-01

    Here we show that, for sub-wavelength particles in a fluid, viscous losses due to shear waves and their influence on neighbouring particles significantly modify the effective acoustic properties, and thereby the conditions at which negative acoustic refraction occurs. Building upon earlier single particle scattering work, we adopt a multiple scattering approach to derive the effective properties (density, bulk modulus, wavenumber). We show,through theoretical prediction, the implications for the design of “soft” (ultrasonic) metamaterials based on locally-resonant sub-wavelength porous rubber particles, through selection of particle size and concentration, and demonstrate tunability of the negative speed zones by modifying the viscosity of the suspending medium. For these lossy materials with complex effective properties, we confirm the use of phase angles to define the backward propagation condition in preference to “single-” and “double-negative” designations.

  11. Cryogenic Thermal Performance Testing of Bulk-Fill and Aerogel Insulation Materials

    Science.gov (United States)

    Scholtens, B. E.; Fesmire, J. E.; Sass, J. P.; Augustynowicz, S. D.; Heckle, K. W.

    2007-01-01

    The research testing and demonstration of new bulk-fill materials for cryogenic thermal insulation systems was performed by the Cryogenics Test Laboratory at NASA Kennedy Space Center. Thermal conductivity testing under actual-use cryogenic conditions is a key to understanding the total system performance encompassing engineering, economics, and materials factors. A number of bulk fill insulation materials, including aerogel beads, glass bubbles, and perlite powder, were tested using a new cylindrical cryostat. Boundary temperatures for the liquid nitrogen boil-off method were 293 K and 78 K. Tests were performed as a function of cold vacuum pressure from high vacuum to no vacuum conditions. Results are compared with other complementary test methods in the range of 300 K to 20 K. Various testing techniques are shown to be required to obtain a complete understanding of the operating performance of a material and to provide data for answers to design engineering questions.

  12. The Use of Small Scale Fire Test Data for the Hazard Assessment of Bulk Materials

    OpenAIRE

    Foley, Marianne

    1995-01-01

    An experimental study of fire testing of solid materials has been carried out to investigate whether or not these tests yield useful data for the burning of materials stored in bulk, for example in warehouses. Tests were performed using the Cone Calorimeter, the HSE third scale room/corridor rig, BS 5852 part 2, and some nonstandard tests. The results have been compared and the problems with fire testing have been discussed with reference to the current literature and trends in fi...

  13. Calibration of DEM models for granular materials using bulk physical tests

    OpenAIRE

    Johnstone, Mical William

    2010-01-01

    From pharmaceutical powders to agricultural grains, a great proportion of the materials handled in industrial situations are granular or particulate in nature. The variety of stesses that the matierals may experience and the resulting bulk behaviours may be complex. In agricultural engineering, a better understanding into agricultural processes such as seeding, harvesting, transporting and storing will help to improve the handling of agricultural grains with optimised solutions. A detailed un...

  14. Tribology of polymeric nanocomposites friction and wear of bulk materials and coatings

    CERN Document Server

    Friedrich, Klaus

    2013-01-01

    Tribology of Polymeric Nanocomposites provides a comprehensive description of polymeric nanocomposites, both as bulk materials and as thin surface coatings, and provides rare, focused coverage of their tribological behavior and potential use in tribological applications. Providing engineers and designers with the preparation techniques, friction and wear mechanisms, property information and evaluation methodology needed to select the right polymeric nanocomposites for the job, this unique book also includes valuable real-world examples of polymeric nanocomposites in a

  15. Development of heat exchanger for high temperature energy storage with bulk materials

    Science.gov (United States)

    Boura, Cristiano Teixeira; Niederwestberg, Stefan; McLeod, Jacqueline; Herrmann, Ulf; Hoffschmidt, Bernhard

    2016-05-01

    This paper gives a general overview of the concept of a high temperature gas-to-particle heat exchanger, the corresponding test facilities and the results of laboratory tests. A description of the optimal bulk material and separator properties and their influences on the operating conditions is also given. The three phenomena pinning, blistering and blocking could be observed during the tests and were analysed in more detail using simulation software.

  16. Neutron spin tomography. A tool to visualize magnetic domains in bulk materials

    International Nuclear Information System (INIS)

    The possibility of a visualization of magnetic domains in bulk materials by the recently proposed tomographic neutron depolarization technique is discussed. In particular a numerical procedure is presented which allows the analysis of tomographic tensorial data taking into account the non-Abelian character of the involved tensors in lowest order. Analyzing schematic data sets it is shown that in principle it is possible to reveal the inner magnetization by tomographic neutron depolarization measurements. (author)

  17. Environment-oriented life cycle analysis of bulk materials, applied in solar cell systems

    International Nuclear Information System (INIS)

    In the solar cell technology several bulk materials (glass, steel, aluminium, concrete, copper, zinc and synthetic materials) are applied intensively. By means of a life cycle analysis (LCA) the environmental effects and bottlenecks of the use of these materials is investigated in this report. Also attention is paid to the options to reduce the environmental effects of photovoltaic (PV) systems by changing processes and/or by redesign of the PV systems. Two systems are studied: solar cells, integrated in pitched roofs, and solar cells on the ground in solar cell arrays. The study is focused on the use of bulk materials in the solar module, the cables and the supporting construction. After brief introductions on the environment-oriented LCA method, the standard construction of PV modules and the principles of solar cells, an overview is given of the present and future material input for the above-mentioned PV-systems. Next, attention is paid to the energy consumption and the most important emissions of the production of the bulk materials. Based on these data three environmental effect scores of the PV systems are calculated and analyzed: the energy consumption, the greenhouse effect or global warming equivalent, and the acidifying effect or acidification equivalent. Also a fourth effect, for which the so-called environmental indicator human toxicity is defined, is described. By means of this indicator the hazardous effects for the public health can be indicated. The sum of the four indicators is a measure for the environmental profile of the roof PV-system and the ground PV-array system. Recommendations are given by which the systems and their environmental profiles can be improved. 29 figs., 50 tabs., 5 appendices, refs

  18. Multi-Stimuli-Responsive Polymer Materials: Particles, Films, and Bulk Gels.

    Science.gov (United States)

    Cao, Zi-Quan; Wang, Guo-Jie

    2016-06-01

    Stimuli-responsive polymers have received tremendous attention from scientists and engineers for several decades due to the wide applications of these smart materials in biotechnology and nanotechnology. Driven by the complex functions of living systems, multi-stimuli-responsive polymer materials have been designed and developed in recent years. Compared with conventional single- or dual-stimuli-based polymer materials, multi-stimuli-responsive polymer materials would be more intriguing since more functions and finer modulations can be achieved through more parameters. This critical review highlights the recent advances in this area and focuses on three types of multi-stimuli-responsive polymer materials, namely, multi-stimuli-responsive particles (micelles, micro/nanogels, vesicles, and hybrid particles), multi-stimuli-responsive films (polymer brushes, layer-by-layer polymer films, and porous membranes), and multi-stimuli-responsive bulk gels (hydrogels, organogels, and metallogels) from recent publications. Various stimuli, such as light, temperature, pH, reduction/oxidation, enzymes, ions, glucose, ultrasound, magnetic fields, mechanical stress, solvent, voltage, and electrochemistry, have been combined to switch the functions of polymers. The polymer design, preparation, and function of multi-stimuli-responsive particles, films, and bulk gels are comprehensively discussed here. PMID:27153184

  19. A robust, melting class bulk superhydrophobic material with heat-healing and self-cleaning properties

    Science.gov (United States)

    Ramakrishna, S.; Santhosh Kumar, K. S.; Mathew, Dona; Reghunadhan Nair, C. P.

    2015-12-01

    Superhydrophobic (SH) materials are essential for a myriad of applications such as anti-icing and self-cleaning due to their extreme water repellency. A single, robust material simultaneously possessing melt-coatability, bulk water repellency, self-cleanability, self-healability, self-refreshability, and adhesiveness has been remaining an elusive goal. We demonstrate a unique class of melt-processable, bulk SH coating by grafting long alkyl chains on silica nanoparticle surface by a facile one-step method. The well-defined nanomaterial shows SH property in the bulk and is found to heal macro-cracks on gentle heating. It retains wettability characteristics even after abrading with a sand paper. The surface regenerates SH features (due to reversible self-assembly of nano structures) quickly at ambient temperature even after cyclic water impalement, boiling water treatment and multiple finger rubbing tests. It exhibits self-cleaning properties on both fresh and cut surfaces. This kind of coating, hitherto undisclosed, is expected to be a breakthrough in the field of melt-processable SH coatings.

  20. A robust, melting class bulk superhydrophobic material with heat-healing and self-cleaning properties

    Science.gov (United States)

    Ramakrishna, S.; Santhosh Kumar, K. S.; Mathew, Dona; Reghunadhan Nair, C. P.

    2015-01-01

    Superhydrophobic (SH) materials are essential for a myriad of applications such as anti-icing and self-cleaning due to their extreme water repellency. A single, robust material simultaneously possessing melt-coatability, bulk water repellency, self-cleanability, self-healability, self-refreshability, and adhesiveness has been remaining an elusive goal. We demonstrate a unique class of melt-processable, bulk SH coating by grafting long alkyl chains on silica nanoparticle surface by a facile one-step method. The well-defined nanomaterial shows SH property in the bulk and is found to heal macro-cracks on gentle heating. It retains wettability characteristics even after abrading with a sand paper. The surface regenerates SH features (due to reversible self-assembly of nano structures) quickly at ambient temperature even after cyclic water impalement, boiling water treatment and multiple finger rubbing tests. It exhibits self-cleaning properties on both fresh and cut surfaces. This kind of coating, hitherto undisclosed, is expected to be a breakthrough in the field of melt-processable SH coatings. PMID:26679096

  1. Standard Guide for Unrestricted Disposition of Bulk Materials Containing Residual Amounts of Radioactivity

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This guide covers the techniques for obtaining approval for release of materials encountered in decontamination and decommissioning (D&D) from restricted use. This would be addressed in the decommissioning plan (E 1281). It applies to materials that do not meet any of the requirements for regulatory control because of radioactivity content. Fig. 1 shows the logic diagram for determining the materials that could be considered for release. Materials that negotiate this logic tree are referred to as “candidate for release based on dose.” 1.2 The objective of this guide is to provide a methodology for distinguishing between material that must be carefully isolated to prevent human contact from that that can be recycled or otherwise disposed of. It applies to material in which the radioactivity is dispersed more or less uniformly throughout the volume of the material (termed residual in bulk form) as opposed to surface contaminated objects. 1.3 Surface contaminated objects are materials externally co...

  2. Mechanical design engineering. NASA/university advanced design program: Lunar Bulk Material Transport Vehicle

    Science.gov (United States)

    Daugherty, Paul; Griner, Stewart; Hendrix, Alan; Makarov, Chris; Martiny, Stephen; Meyhoefer, Douglas Ralph; Platt, Cody Claxton; Sivak, John; Wheeler, Elizabeth Fitch

    1988-06-01

    The design of a Lunar Bulk Material Transport Vehicle (LBMTV) is discussed. Goals set in the project include a payload of 50 cubic feet of lunar soil with a lunar of approximately 800 moon-pounds, a speed of 15 mph, and the ability to handle a grade of 20 percent. Thermal control, an articulated steering mechanism, a dump mechanism, a self-righting mechanism, viable power sources, and a probable control panel are analyzed. The thermal control system involves the use of small strip heaters to heat the housing of electronic equipment in the absence of sufficient solar radiation and multi-layer insulation during periods of intense solar radiation. The entire system uses only 10 W and weighs about 60 pounds, or 10 moon-pounds. The steering mechanism is an articulated steering joint at the center of the vehicle. It utilizes two actuators and yields a turning radius of 10.3 feet. The dump mechanism rotates the bulk material container through an angle of 100 degree using one actuator. The self-righting mechanism consists of two four bar linkages, each of which is powered by the same size actuator as the other linkages. The LBMTV is powered by rechargeable batteries. A running time of at least two hours is attained under a worst case analysis. The weight of the batteries is 100 pounds. A control panel consisting of feedback and control instruments is described. The panel includes all critical information necessary to control the vehicle remotely. The LBMTV is capable of handling many types of cargo. It is able to interface with many types of removable bulk material containers. These containers are made to interface with the three-legged walker, SKITTER. The overall vehicle is about 15 feet in length and has a weight of about 1000 pounds, or 170 lunar pounds.

  3. Mechanical design engineering. NASA/university advanced design program: Lunar Bulk Material Transport Vehicle

    Science.gov (United States)

    Daugherty, Paul; Griner, Stewart; Hendrix, Alan; Makarov, Chris; Martiny, Stephen; Meyhoefer, Douglas Ralph; Platt, Cody Claxton; Sivak, John; Wheeler, Elizabeth Fitch

    1988-01-01

    The design of a Lunar Bulk Material Transport Vehicle (LBMTV) is discussed. Goals set in the project include a payload of 50 cubic feet of lunar soil with a lunar of approximately 800 moon-pounds, a speed of 15 mph, and the ability to handle a grade of 20 percent. Thermal control, an articulated steering mechanism, a dump mechanism, a self-righting mechanism, viable power sources, and a probable control panel are analyzed. The thermal control system involves the use of small strip heaters to heat the housing of electronic equipment in the absence of sufficient solar radiation and multi-layer insulation during periods of intense solar radiation. The entire system uses only 10 W and weighs about 60 pounds, or 10 moon-pounds. The steering mechanism is an articulated steering joint at the center of the vehicle. It utilizes two actuators and yields a turning radius of 10.3 feet. The dump mechanism rotates the bulk material container through an angle of 100 degree using one actuator. The self-righting mechanism consists of two four bar linkages, each of which is powered by the same size actuator as the other linkages. The LBMTV is powered by rechargeable batteries. A running time of at least two hours is attained under a worst case analysis. The weight of the batteries is 100 pounds. A control panel consisting of feedback and control instruments is described. The panel includes all critical information necessary to control the vehicle remotely. The LBMTV is capable of handling many types of cargo. It is able to interface with many types of removable bulk material containers. These containers are made to interface with the three-legged walker, SKITTER. The overall vehicle is about 15 feet in length and has a weight of about 1000 pounds, or 170 lunar pounds.

  4. Sensitive absorption measurements in bulk material and coatings using a photothermal and a photoacoustic spectrometer

    Science.gov (United States)

    Fieberg, S.; Waasem, N.; Kühnemann, F.; Buse, K.

    2014-02-01

    Bulk and surface absorption in lithium triborate (LBO) and lithium niobate (LiNbO3) are measured using two sensitive measurement techniques, a photoacoustic spectrometer (PAS) and a photothermal common-path interferometer (PCI). As pump light sources, optical parametric oscillators are employed, covering the wavelength ranges 212 - 2500 nm (PAS) and 1460 - 1900 nm and 2460 - 3900 nm (PCI). The spectrometers are used to measure absorption spectra of optical materials across this wide spectral range and to compare the methods in the shared wavelength regime.

  5. Preferred orientation and its effect on bulk physical properties of polycrystalline materials

    International Nuclear Information System (INIS)

    Averaging methods used to derive preferred orientation parameters of polycrystalline materials are examined with particular reference to those parameters suitable for predicting bulk physical properties from the properties of individual crystallites. Attempts to correlate experimental values of thermal expansion and irradiation growth coefficients of polycrystalline graphite and zirconium alloys with the commonly used preferred orientation f-parameter are reviewed. The physical basis behind the derivation of the f-parameter is examined in some detail and the consequent restrictions on its general applicability pointed out. (author)

  6. 49 CFR 173.243 - Bulk packaging for certain high hazard liquids and dual hazard materials which pose a moderate...

    Science.gov (United States)

    2010-10-01

    ... conforming to 46 CFR part 64 with design pressure of at least 172.4 kPa (25 psig) are authorized. Unless... 49 Transportation 2 2010-10-01 2010-10-01 false Bulk packaging for certain high hazard liquids and... Packaging for Hazardous Materials Other Than Class 1 and Class 7 § 173.243 Bulk packaging for certain...

  7. Materials Analysis of CED Nb Films Being Coated on Bulk Nb Single Cell SRF Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xin; Reece, Charles; Palczewski, Ari; Ciovati, Gianluigi; Krishnan, Mahadevan; James, Colt; Irfan, Irfan

    2013-09-01

    This study is an on-going research on depositing a Nb film on the internal wall of bulk Nb single cell SRF cavities, via a cathodic arc Nb plasma ions source, an coaxial energetic condensation (CED) facility at AASC company. The motivation is to firstly create a homoepitaxy-like Nb/Nb film in a scale of a ~1.5GHz RF single cell cavity. Next, through SRF measurement and materials analysis, it might reveal the baseline properties of the CED-type homoepitaxy Nb films. Literally, a top-surface layer of Nb films which sustains SRF function, always grows up in homo-epitaxy mode, on top of a Nb nucleation layer. Homo-epitaxy growth of Nb must be the final stage (a crystal thickening process) of any coatings of Nb film on alternative cavity structure materials. Such knowledge of Nb-Nb homo-epitaxy is useful to create future realistic SRF cavity film coatings, such as hetero-epitaxy Nb/Cu Films, or template-layer-mitigated Nb films. One large-grain, and three fine grain bulk Nb cavities were coated. They went through cryogenic RF measurement. Preliminary results show that the Q0 of a Nb film could be as same as the pre-coated bulk Nb surface (which received a chemically-buffered polishing plus a light electro-polishing); but quality factor of two tested cavities dropped quickly. We are investigating if the severe Q-slope is caused by hydrogen incorporation before deposition, or is determined by some structural defects during Nb film growth.

  8. Cellulose-wheat gluten bulk plastic materials produced from processing raw powders by severe shear deformation.

    Science.gov (United States)

    Zhang, Xiaoqing; Wu, Xiaolin; Xia, Kenong

    2013-02-15

    Cellulose-based renewable bulk plastics with significantly improved mechanical properties were produced by using a small proportion of wheat gluten (WG) as an additive to enhance the material processing capability. The strong shear-deformation during equal channel angular pressing (ECAP) generated effective chain penetration and strong intermolecular interactions between the amorphous cellulose and WG components. The micro-cracking of the obtained materials was minimized, and the processing temperature was reduced. The crystallinity of the cellulose component was also decreased, whereas the crystalline size and regularity was less modified. The present study has further demonstrated that ECAP is a promising methodology to produce renewable and biodegradable "wood plastics" from cellulose-based agricultural waste. PMID:23399278

  9. In Situ Neutron Scattering Study of Nanostructured PbTe-PbS Bulk Thermoelectric Material

    Science.gov (United States)

    Ren, Fei; Schmidt, Robert; Case, Eldon D.; An, Ke

    2016-07-01

    Nanostructures play an important role in thermoelectric materials. Their thermal stability, such as phase change and evolution at elevated temperatures, is thus of great interest to the thermoelectric community. In this study, in situ neutron diffraction was used to examine the phase evolution of nanostructured bulk PbTe-PbS materials fabricated using hot pressing and pulsed electrical current sintering (PECS). The PbS second phase was observed in all samples in the as-pressed condition. The temperature dependent lattice parameter and phase composition data show an initial formation of PbS precipitates followed by a redissolution during heating. The redissolution process started around 570-600 K, and completed at approximately 780 K. During cooling, the PECS sample followed a reversible curve while the heating/cooling behavior of the hot pressed sample was irreversible.

  10. The transport of bulk quantities of naturally occurring radioactive materials - with the focus on zircon sand

    International Nuclear Information System (INIS)

    Zircon is a naturally occurring silicate of zirconium, which is used, in large quantities (∼ 1 million tons per annum) for its refractory properties and its extreme chemical inertness. All zircons contain uranium and thorium bound into the crystal lattice, generally at levels up to 500 ppm of uranium plus thorium. This paper focuses on one aspect of the zircon industry - the ability to safely transport large quantities of the zircon sand. Currently zircon is not classified as a radioactive material for transport purposes. However this is because of a factor used in the exemption clauses of the IAEA Code on safe transport of radioactive materials. The objective of this study was to determine the validity of this factor, and was submitted as part of an IAEA CRP. The study is based primarily on measured rather than modeled data and covers the transport of large quantities of zircon from producers in South Africa to customers in Europe. Both occupational exposure of workers and exposure of members of the public have been considered. The transport routes studied cover rail, road, ocean going ship and inland barge transport of unpackaged bulk products. The study showed that the most exposed member of the public would receive 10μSv/annum, whilst the most exposed worker would receive 144μSv/ annum of exposure. It is concluded that these levels are well below all regulatory limits for such activities involving naturally occurring materials. The study also showed that normal operational exposures are higher than those in accident scenarios, a feature which does not occur with higher activity materials. It is further concluded that the study validates the use of the factor of 10 in TS-R-1, as applied to zircon sand. Additionally it is also concluded that the exemption currently applied to the transportation of bulk zircon sand is valid. (author)

  11. Application of high power X ray generators for processing bulk materials

    International Nuclear Information System (INIS)

    High power, high energy X ray (bremsstrahlung) generators are suitable sources of ionizing radiation for processing bulk materials. The basic physical, chemical and biological effects of irradiating materials with this form of energy are essentially the same as the effects obtained with gamma rays and accelerated electrons. The choice of energy source for a particular application depends on practical aspects of the irradiation process, such as material thickness, throughput rate, dose uniformity ratio and economics. X ray photons are emitted when energetic electrons strike any material. The intensity increases with the energy of the incident electrons and with the atomic number of the target material. With electron energies greater than 1 MeV, the angular distribution of the emitted radiation is concentrated in the direction of the electron beam. The efficiency for conversion incident electron beam power to useful X ray power in the forward direction is relatively low; typically about 8% at 5.0 MeV, 13% at 7.5 MeV and 16% at 10 MeV. The low converting efficiency can be compensated by using high power electron beams. The broad energy spectrum of bremsstrahlung (braking radiation) extends up to the maximum energy of the incident electrons. Although the most probable photon energy is only about 0.3 MeV, the penetration is significantly greater than gamma rays from large area cobalt-60 sources. The penetration of high energy X rays allows large loads of high density materials to be irradiated with low dose uniformity ratios. The narrow X ray beam allows pallet-sized loads to be irradiated singly, thus shortening the irradiation time. This facilitates changing the processing conditions for different materials. In contrast to the emission of gamma rays from radioactive sources, X ray generators can be switched off when not needed for production. This saves energy and simplifies maintenance procedures. High power, high energy electron accelerators are now available, with

  12. 230Th/U dating of Last Interglacial brain corals from Bonaire (southern Caribbean) using bulk and theca wall material

    Science.gov (United States)

    Obert, J. Christina; Scholz, Denis; Felis, Thomas; Brocas, William M.; Jochum, Klaus P.; Andreae, Meinrat O.

    2016-04-01

    We compared the suitability of two skeletal materials of the Atlantic brain coral Diploria strigosa for 230Th/U-dating: the commonly used bulk material comprising all skeletal elements and the denser theca wall material. Eight fossil corals of presumably Last Interglacial age from Bonaire, southern Caribbean Sea, were investigated, and several sub-samples were dated from each coral. For four corals, both the ages and the activity ratios of the bulk material and theca wall agree within uncertainty. Three corals show significantly older ages for their bulk material than for their theca wall material as well as substantially elevated 232Th content and (230Th/238U) ratios. The bulk material samples of another coral show younger ages and lower (230Th/238U) ratios than the corresponding theca wall samples. This coral also contains a considerable amount of 232Th. The application of the available open-system models developed to account for post-depositional diagenetic effects in corals shows that none of the models can successfully be applied to the Bonaire corals. The most likely explanation for this observation is that the assumptions of the models are not fulfilled by our data set. Comparison of the theca wall and bulk material data enables us to obtain information about the open-system processes that affected the corals. The corals showing apparently older ages for their bulk material were probably affected by contamination with a secondary (detrital) phase. The most likely source of the detrital material is carbonate sand. The higher (230Th/232Th) ratio of this material implies that detrital contamination would have a much stronger impact on the ages than a contaminant with a bulk Earth (230Th/232Th) ratio and that the threshold for the commonly applied 232Th reliability criterion would be much lower than the generally used value of 1 ng g-1. The coral showing apparently younger ages for its bulk material was probably influenced by more than one diagenetic process. A

  13. A bulk metal/ceramic composite material with a cellular structure

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhankui; YAO Kefu; LI Jingfeng

    2006-01-01

    A bulk metal/ceramic composite material with a honeycomb-like micro-cell structure has been prepared by sintering the spherical Al90Mn9Ce1 alloy powders clad by Al2O3 nano-powder with the spark plasma sintering (SPS) technique. The as-prepared material consists of Al90Mn9Ce1 alloy cell and closed Al2O3 ceramic cell wall. The diameter of the cells is about 20―40 μm, while a thickness of the cell wall is about 1―2 μm. The ultimate compressive strength of the as-sintered materials is about 514 MPa, while its fracture strain is up to about 0.65 %. This composite material might possess good anti-corrosion, thermal endurance and other potential properties due to its unique microstructure. The result shows that the Al90Mn9Ce1/Al2O3 composite powders can be sintered by spark plasma sintering technique despite the large difference in their sintering temperature. This work offers a way of designing and preparing metal/ceramic composite material with functional property.

  14. Development of Negative Index of Refraction Metamaterials with Split Ring Resonators and Wires for RF Lens Applications

    Science.gov (United States)

    Parazzoli, Claudio G.; Greegor, Robert B.; Tanielian, M. H.

    Metamaterials are engineered ring and wire composites whose response to an incident electromagnetic wave can be described by an effective negative dielectric permittivity ɛ and magnetic permeability μ. Simultaneous negative ɛ and μ within a given frequency band of a metamaterial gives rise to a negative index of refraction n. This has been demonstrated via a Snell's law experiment. The electromagnetic properties of many metamaterial structures in the microwave region are investigated through numerical simulations and experiments. A negative index of refraction, n, allows lenses with reduced primary (Seidel) aberrations compared to equivalent positive index lens. This is demonstrated both for cylindrical lenses and spherical lenses, as well as for the gradient index lenses. Detailed field maps of the focal region of the metamaterials lenses are made and compared to a comparable positive index of refraction lens.

  15. Super-resolution imaging by one-dimensional, microwave left-handed metamaterials with an effective negative index

    International Nuclear Information System (INIS)

    Superlenses based on metamaterials are promising candidates for achieving subwavelength resolution. We report here our experimental studies on super-resolution imaging from one-dimensional (1D) negative index metamaterial superlenses at microwave frequencies. The metamaterial structure under investigation is shown to have a left-handed transmission band at frequencies where both effective permittivity and permeability are negative. The retrieved effective parameters are in good agreement with the measurements. We achieved a resolution of 0.2λ by imaging a single point source from a 1D superlens. Moreover, the effect of the superlens' thickness on the resolution is studied. A thicker superlens suffers from more losses, which in turn reduces the resolution. Two point sources that were separated by distances that were smaller than a half-wavelength were successfully resolved with the negative index superlens

  16. Super-resolution imaging by one-dimensional, microwave left-handed metamaterials with an effective negative index

    Energy Technology Data Exchange (ETDEWEB)

    Ozbay, Ekmel; Li, Zhaofeng; Aydin, Koray [Nanotechnology Research Center and Department of Physics, Bilkent University, Bilkent, 06800 Ankara (Turkey)], E-mail: ozbay@bilkent.edu.tr, E-mail: aydin@fen.bilkent.edu.tr

    2008-07-30

    Superlenses based on metamaterials are promising candidates for achieving subwavelength resolution. We report here our experimental studies on super-resolution imaging from one-dimensional (1D) negative index metamaterial superlenses at microwave frequencies. The metamaterial structure under investigation is shown to have a left-handed transmission band at frequencies where both effective permittivity and permeability are negative. The retrieved effective parameters are in good agreement with the measurements. We achieved a resolution of 0.2{lambda} by imaging a single point source from a 1D superlens. Moreover, the effect of the superlens' thickness on the resolution is studied. A thicker superlens suffers from more losses, which in turn reduces the resolution. Two point sources that were separated by distances that were smaller than a half-wavelength were successfully resolved with the negative index superlens.

  17. Super-resolution imaging by one-dimensional, microwave left-handed metamaterials with an effective negative index

    Science.gov (United States)

    Ozbay, Ekmel; Li, Zhaofeng; Aydin, Koray

    2008-07-01

    Superlenses based on metamaterials are promising candidates for achieving subwavelength resolution. We report here our experimental studies on super-resolution imaging from one-dimensional (1D) negative index metamaterial superlenses at microwave frequencies. The metamaterial structure under investigation is shown to have a left-handed transmission band at frequencies where both effective permittivity and permeability are negative. The retrieved effective parameters are in good agreement with the measurements. We achieved a resolution of 0.2λ by imaging a single point source from a 1D superlens. Moreover, the effect of the superlens' thickness on the resolution is studied. A thicker superlens suffers from more losses, which in turn reduces the resolution. Two point sources that were separated by distances that were smaller than a half-wavelength were successfully resolved with the negative index superlens.

  18. Shear-mediated contributions to the effective properties of soft acoustic metamaterials including negative index

    OpenAIRE

    Derek Michael Forrester; Valerie J. Pinfield

    2015-01-01

    Here we show that, for sub-wavelength particles in a fluid, viscous losses due to shear waves and their influence on neighbouring particles significantly modify the effective acoustic properties, and thereby the conditions at which negative acoustic refraction occurs. Building upon earlier single particle scattering work, we adopt a multiple scattering approach to derive the effective properties (density, bulk modulus, wavenumber). We show,through theoretical prediction, the implications for ...

  19. A Miniaturized Antenna with Negative Index Metamaterial Based on Modified SRR and CLS Unit Cell for UWB Microwave Imaging Applications

    OpenAIRE

    Md. Moinul Islam; Mohammad Tariqul Islam; Md. Samsuzzaman; Mohammad Rashed Iqbal Faruque; Norbahiah Misran; Mohd Fais Mansor

    2015-01-01

    A miniaturized antenna employing a negative index metamaterial with modified split-ring resonator (SRR) and capacitance-loaded strip (CLS) unit cells is presented for Ultra wideband (UWB) microwave imaging applications. Four left-handed (LH) metamaterial (MTM) unit cells are located along one axis of the antenna as the radiating element. Each left-handed metamaterial unit cell combines a modified split-ring resonator (SRR) with a capacitance-loaded strip (CLS) to obtain a design architecture ...

  20. Numerical simulation and experimental validation of the microindentation test applied to bulk elastoplastic materials

    International Nuclear Information System (INIS)

    The main objective of this work is to compare numerically simulated load–indentation depth curves together with deformation and stress fields underneath a sharp indenter for a set of mystical materials. Firstly, a numerical simulation and experimental validation of the microindentation test applied to three different bulk elastoplastic materials (copper, stainless steel and pure aluminium) using two indenters (Berkovich and spherical) are presented. The simulation of these microindentation tests is carried out using the finite element large strain elastoplastic and contact models. The corresponding results are particularly aimed at addressing the following aspects: the influence of the indenter geometry on both the load–indentation depth curve and range of plastic strains involved in the test, the comparison of the 3D results for the sharp indenter with those of the 2D approximation, the capabilities of the modelling through experimental validation of the numerical predictions and, in addition, an assessment of the indentation size effect. Secondly, the numerical results of Berkovich indentation applied to a set of mystical materials are exhaustively discussed. Although it is effectively shown that these mystical materials exhibit indistinguishable load–penetration depth curves during the loading phase, an important aspect that has not been previously addressed is that some clear differences in their responses are obtained for the unloading stage. Finally, the deformation and stress contours at the maximum indentation force and after unloading are particularly analysed. (paper)

  1. Latex particles functionalized with transition metals ferrocyanides for cesium uptake and decontamination of solid bulk materials

    International Nuclear Information System (INIS)

    Decontamination of spent ion-exchange resins, corrosion-unstable metal structures, soil, ground, and construction materials contaminated by fission, corrosion and transuranic radionuclides remains one of the most urgent and complicated ecological problems. Among the existing methods having different efficiencies in regard to such materials decontamination, application of selective sorbents put into a humid medium to be decontaminated (ground, bulk materials) appears to be rather extensive. However, the efficiency of such an approach is significantly limited by difficulties concerned with uniform sorbent distribution in porous media and completeness of spent sorbents removal for final disposal. In this paper we suggest a principally new approach to preparation of colloid-stable selective sorbents for cesium uptake using immobilization of transition metals (cobalt, nickel, and copper) ferrocyanides in nanosized carboxylic latex emulsions. The effects of ferrocyanide composition, pH, and media salinity on the sorption properties of the colloid-stable sorbents toward cesium ions were studied in solutions containing up to 200 g/1 sodium nitrate or potassium chloride. The sorption capacities of the colloid sorbents based on mixed potassium/transition metals ferrocyanides were in the range 1.45-1.86 mol Cs/mol ferrocyanide with the highest value found for the copper ferrocyanide. It was shown that the obtained colloid-stable sorbents were capable to penetrate through bulk materials without filtration that makes them applicable for decontamination of solids, e.g. soils, zeolites, spent ion-exchange resins contaminated with cesium radionuclides. After decontamination of liquid or solid radioactive wastes the colloid-stable sorbents can be easily separated from solutions by precipitation with cationic flocculants providing localization of radionuclides in a small volume of the precipitates formed. Besides, functionalized latex particles can be used for preparation of carbon

  2. AC Conductivity and Dielectric Relaxation Behavior of Sb2S3 Bulk Material

    Science.gov (United States)

    Abd El-Rahman, K. F.; Darwish, A. A. A.; Qashou, Saleem I.; Hanafy, T. A.

    2016-07-01

    The Sb2S3 bulk material was used for next-generation anode for lithium-ion batteries. Alternative current (AC) conductivity, dielectric properties and electric modulus of Sb2S3 have been investigated. The measurements were carried out in the frequency range from 40 Hz to 5 MHz and temperature range from 293 K to 453 K. The direct current (DC) conductivity, σ DC, shows an activated behavior and the calculated activation energy is 0.50 eV. The AC conductivity, σ AC, was found to increase with the increase of temperature and frequency. The conduction mechanism of σ AC was controlled by the correlated barrier hopping model. The behavior of the dielectric constant, ɛ', and dielectric loss index, ɛ'', reveal that the polarization process of Sb2S3 is dipolar in nature. The behavior of both ɛ' and ɛ'' reveals that bulk Sb2S3 has no ferroelectric or piezoelectric phase transition. The dielectric modulus, M, gives a simple method for evaluating the activation energy of the dielectric relaxation. The calculated activation energy from M is 0.045 eV.

  3. Evaluation of simulation techniques for radiation damage in the bulk of fusion first wall materials

    International Nuclear Information System (INIS)

    An international workshop on 'Evaluation of Simulation Techniques for Radiation Damage in the Bulk of Fusion First Wall Materials' was held at Interlaken, Switzerland, June 27-30 1983. The idea was to gather a small group of people (∼20) actively engaged in experimental simulation of bulk radiation damage in the first wall material (e.g. damage by fusion neutrons). Because of the very positive response the number of participants ended up at 36 (from Belgium, Denmark, Federal Republic of Germany, France, Italy (ISPRA), Japan, Switzerland, U.K. and U.S.A.). The workshop was initially rather restrictive in the definition of experimental facilities for simulation of the first wall material, as it included only those facilities which simultaneously introduce helium (at high rate) and displacement damage . At the workshop a few simulation techniques that do not fulfill this requirement were discussed together with those that do. The basic programme of the workshop was composed of a series of invited presentations intended to cover the whole spectrum of simulation techniques and some of the underlying physics and basic technology. Time was also reserved for short presentations on any subject that the participants found relevant. Throughout the workshop ample time was allocated for discussions. As it turned out, the discussions tended to focus on the evaluation of the general situation for simulation of radiation damage in the first wall. The workshop covered the following topics: the concept of simulation; the important parameters (He generation to damage rate ratio; displacement damage rate; He generation rate; total doses; H generation; solid transmutation products; cascade effects; effect of beam pulsation; specimen dimension); and the irradiation effects (mechanical properties and swelling; microstructure). There was general agreement among the participants that ideal simulation, providing unambiguous information about the behaviour of the first wall material, is at

  4. Efficient coupling of light to graphene plasmons by compressing surface polaritons with tapered bulk materials.

    Science.gov (United States)

    Nikitin, A Yu; Alonso-González, P; Hillenbrand, R

    2014-05-14

    Graphene plasmons promise exciting nanophotonic and optoelectronic applications. Owing to their extremely short wavelengths, however, the efficient coupling of photons to propagating graphene plasmons-critical for the development of future devices-can be challenging. Here, we propose and numerically demonstrate coupling between infrared photons and graphene plasmons by the compression of surface polaritons on tapered bulk slabs of both polar and doped semiconductor materials. Propagation of surface phonon polaritons (in SiC) and surface plasmon polaritons (in n-GaAs) along the tapered slabs compresses the polariton wavelengths from several micrometers to around 200 nm, which perfectly matches the wavelengths of graphene plasmons. The proposed coupling device allows for a 25% conversion of the incident energy into graphene plasmons and, therefore, could become an efficient route toward graphene plasmon circuitry. PMID:24773123

  5. Producing Bulk Ultrafine-Grained Materials by Severe Plastic Deformation: Ten Years Later

    Science.gov (United States)

    Valiev, Ruslan Z.; Estrin, Yuri; Horita, Zenji; Langdon, Terence G.; Zehetbauer, Michael J.; Zhu, Yuntian

    2016-04-01

    It is now well established that the processing of bulk solids through the application of severe plastic deformation (SPD) leads to exceptional grain refinement to the submicrometer or nanometer level. Extensive research over the last decade has demonstrated that SPD processing also produces unusual phase transformations and leads to the introduction of a range of nanostructural features, including nonequilibrium grain boundaries, deformation twins, dislocation substructures, vacancy agglomerates, and solute segregation and clustering. These many structural changes provide new opportunities for fine tuning the characteristics of SPD metals to attain major improvements in their physical, mechanical, chemical, and functional properties. This review provides a summary of some of these recent developments. Special emphasis is placed on the use of SPD processing in achieving increased electrical conductivity, superconductivity, and thermoelectricity, an improved hydrogen storage capability, materials for use in biomedical applications, and the fabrication of high-strength metal-matrix nanocomposites.

  6. Modeling the material properties at the onset of damage initiation in bulk potassium dihydrogen phosphate crystals

    Science.gov (United States)

    Demos, Stavros G.; Feit, Michael D.; Duchateau, Guillaume

    2014-10-01

    A model simulating transient optical properties during laser damage in the bulk of KDP/DKDP crystals is presented. The model was developed and tested using as a benchmark its ability to reproduce the well-documented damage initiation behaviors but most importantly, the salient behavior of the wavelength dependence of the damage threshold. The model involves two phases. During phase I, the model assumes a moderate localized initial absorption that is strongly enhanced during the laser pulse via excited state absorption and thermally driven generation of additional point defects in the surrounding material. The model suggests that during a fraction of the pulse duration, the host material around the defect cluster is transformed into a strong absorber that leads to significant increase of the local temperature. During phase II, the model suggests that the excitation pathway consists mainly of one photon absorption events within a quasicontinuum of short-lived vibronic defect states spanning the band gap that was generated after the initial localized heating of the material due to thermal quenching of the excited state lifetimes. The width of the transition (steps) between different number of photons is governed by the instantaneous temperature, which was estimated using the experimental data. The model also suggests that the critical physical parameter prior to initiation of breakdown is the conduction band electron density. This model, employing very few free parameters, for the first time is able to quantitatively reproduce the wavelength dependence of the damage initiation threshold, and thus provides important insight into the physical processes involved.

  7. Time-resolved x-ray diffraction techniques for bulk polycrystalline materials under dynamic loading

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, P. K.; Hustedt, C. J.; Zhao, M.; Ananiadis, A. G.; Hufnagel, T. C. [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Vecchio, K. S. [Department of NanoEngineering, University of California San Diego, La Jolla, California 92093 (United States); Huskins, E. L. [Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee 37830 (United States); US Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, Maryland 21005 (United States); Casem, D. T. [US Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, Maryland 21005 (United States); Gruner, S. M. [Department of Physics, Cornell University, Ithaca, New York 14853 (United States); Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, New York 14853 (United States); Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853 (United States); Tate, M. W.; Philipp, H. T.; Purohit, P.; Weiss, J. T. [Department of Physics, Cornell University, Ithaca, New York 14853 (United States); Woll, A. R. [Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, New York 14853 (United States); Kannan, V.; Ramesh, K. T. [Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Kenesei, P.; Okasinski, J. S.; Almer, J. [X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2014-09-15

    We have developed two techniques for time-resolved x-ray diffraction from bulk polycrystalline materials during dynamic loading. In the first technique, we synchronize a fast detector with loading of samples at strain rates of ∼10{sup 3}–10{sup 4} s{sup −1} in a compression Kolsky bar (split Hopkinson pressure bar) apparatus to obtain in situ diffraction patterns with exposures as short as 70 ns. This approach employs moderate x-ray energies (10–20 keV) and is well suited to weakly absorbing materials such as magnesium alloys. The second technique is useful for more strongly absorbing materials, and uses high-energy x-rays (86 keV) and a fast shutter synchronized with the Kolsky bar to produce short (∼40 μs) pulses timed with the arrival of the strain pulse at the specimen, recording the diffraction pattern on a large-format amorphous silicon detector. For both techniques we present sample data demonstrating the ability of these techniques to characterize elastic strains and polycrystalline texture as a function of time during high-rate deformation.

  8. Materials processing, pulsed field magnetization and field-pole application to propulsion motors on Gd123 bulk superconductors

    International Nuclear Information System (INIS)

    Gd123 bulk superconductor is one of the promising magnet materials. We studied the materials processing to grow high performance magnet with a doping of nano-sized metal oxides such as ZrO2 as a candidature of pinning centre. The enhancement of the critical current density was obtained. Growth of nano-sized particles of Gd211 in addition to BaZrO3 were observed by TEM. The formation of nano-sized particles appears a key to improve the integrated flux trapped inside the bulks and the TEM reveals an intriguing effect of the addition to the microstructure of bulk materials. Magnetization process is crucial especially for an extended machinery. Pulsed field magnetization was applied to the field-pole bulk on the rotor disk of the tested synchronous motor. The trapped flux density of 1.3 T for Gd123 bulk sample and of 60 mm diameter was reached in the limited dimension of the tested motor by a step cooling method down to 38 K with a closed-cycle condensed neon. The pulsed magnetic field was applied with a new type of split-armature coil. A large bulk of 140 mm diameter has also shown a potential flux trapping superior to other smaller specimens. The bulk magnet provides a strong magnetic field around the bulk body itself with high current density relative to a coil winding. A comparative drawing of a 'torque density' of a variety of motors which is defined as the torque divided by the volume of the motor indicates a potential advantage of bulk motor as a super permanent magnet motor

  9. Grism compressor for carrier-envelope phase-stable millijoule-energy chirped pulse amplifier lasers featuring bulk material stretcher.

    Science.gov (United States)

    Ricci, A; Jullien, A; Forget, N; Crozatier, V; Tournois, P; Lopez-Martens, R

    2012-04-01

    We demonstrate compression of amplified carrier-envelope phase (CEP)-stable laser pulses using paired transmission gratings and high-index prisms, or grisms, with chromatic dispersion matching that of a bulk material pulse stretcher. Grisms enable the use of larger bulk stretching factors and thereby higher energy pulses with lower B-integral in a compact amplifier design suitable for long-term CEP control. PMID:22466193

  10. The role of new particle surfaces in synthesizing bulk nanostructured metallic materials by powder metallurgy

    International Nuclear Information System (INIS)

    The role of new particle surfaces in synthesizing bulk nanostructured metallic materials by consolidation of nanostructured powders and nanopowders is analysed by developing three simple mathematical equations for calculating the α factor for different thermomechanical powder consolidation processes such as hot pressing, high pressure torsion and extrusion. The α factor is the fraction of the area of the powder particle surfaces newly formed during consolidation over the total particle surface area which includes both pre-existing surface area and the newly formed surface area. It is demonstrated that the values of the α factor calculated using these equations can be reasonably used to predict the level of inter-particle atomic bonding that is likely to be achieved through cold-welding by the above mentioned typical thermomechanical powder consolidation processes which also include high energy mechanical milling. Based on this analysis, it is clear that uniaxial hot pressing of a powder compact in a rigid die at low homologous temperatures (m) is unlikely to be capable of achieving a sufficiently high level of inter-particle atomic bonding for producing a high quality consolidated material, while processes involving a large amount of plastic deformation have such capabilities.

  11. Novel low temperature processing techniques for apatite ceramics and chitosan polymer composite bulk materials and its mechanical properties

    International Nuclear Information System (INIS)

    Highlights: ► CHI and DCPD were mixed in nano-scale by co-precipitation method. ► Bulk CHI/HA materials derived from the CHI/DCPD hybrid material were obtained by hydrothermal hot-pressing. ► Fracture toughness of the obtained bulk materials was enhanced from 0.30 to 0.40 MPam1/2 by the CHI hybridization. - Abstract: A co-precipitation method was used for processing chitosan (CHI)/calcium hydrogen phosphate dehydrate (DCPD) hybrid material. CHI solution was mixed into 1.0-M calcium nitrate solution. CHI/DCPD hybrid material was prepared by the above explained addition of CHI and Ca ion source to 1.0-M diammonium hydrogen phosphate solution. It was observed by transmission electron microscopy that CHI and DCPD were mixed within submicron meter scale. CHI/HA bulk materials derived from the CHI/DCPD hybrid materials were obtained by using a hydrothermal hot-pressing (HHP) method. A pressure of 40 MPa was initially applied to the sample. An HHP autoclave was heated up to 150 °C for 2 h. Modified 3-point bending tests were conducted to obtain an easy estimate of the fracture toughness for the CHI/HA bulk materials made with the HHP method. The critical stress intensity factor Kc of the fabricated CHI/HA bulk materials was enhanced from 0.30 to 0.40 MPam1/2 by the hybridization of CHI into DCPD.

  12. Molecular level assessment of thermal transport and thermoelectricity in materials: From bulk alloys to nanostructures

    Science.gov (United States)

    Kinaci, Alper

    The ability to manipulate material response to dynamical processes depends on the extent of understanding of transport properties and their variation with chemical and structural features in materials. In this perspective, current work focuses on the thermal and electronic transport behavior of technologically important bulk and nanomaterials. Strontium titanate is a potential thermoelectric material due to its large Seebeck coefficient. Here, first principles electronic band structure and Boltzmann transport calculations are employed in studying the thermoelectric properties of this material in doped and deformed states. The calculations verified that excessive carrier concentrations are needed for this material to be used in thermoelectric applications. Carbon- and boron nitride-based nanomaterials also offer new opportunities in many applications from thermoelectrics to fast heat removers. For these materials, molecular dynamics calculations are used to evaluate lattice thermal transport. To do this, first, an energy moment term is reformulated for periodic boundary conditions and tested to calculate thermal conductivity from Einstein relation in various systems. The influences of the structural details (size, dimensionality) and defects (vacancies, Stone-Wales defects, edge roughness, isotopic disorder) on the thermal conductivity of C and BN nanostructures are explored. It is observed that single vacancies scatter phonons stronger than other type of defects due to unsatisfied bonds in their structure. In pristine states, BN nanostructures have 4-6 times lower thermal conductivity compared to C counterparts. The reason of this observation is investigated on the basis of phonon group velocities, life times and heat capacities. The calculations show that both phonon group velocities and life times are smaller in BN systems. Quantum corrections are also discussed for these classical simulations. The chemical and structural diversity that could be attained by

  13. HIPPO, the high-pressure preferred orientation diffractometer at LANSCE for characterization of bulk materials

    International Nuclear Information System (INIS)

    United States National Laboratory researchers and University of California faculty, representing a broad range of scientific disciplines, is building a novel time-of-flight (TOF) neutron diffractometer and associated in situ equipment at the Manuel Lujan Jr. Neutron Scattering Center (Lujan Center), under the auspices of the United States Department of Energy. The goal with the High-Pressure Preferred Orientation Instrument (HIPPO) is to investigate dynamic processes in heterogeneous bulk materials in a variety of environments. The instrument, which will become available in summer 2001, has the extremely high count-rates necessary to study time-dependent processes in small (1-mm diameter) and large (2-cm diameter) samples, and in a large variety of environmental conditions (10-2000 K cryostats and furnaces, 0-20 GPa pressure vessels, straining cells, goniometers, magnets, etc.). The 3-D arrangement of detectors allows direct measurements of crystal orientation distributions in polycrystalline materials. The analysis of TOF diffraction patterns with versatile Rietveld codes provides simultaneous information on crystal structure, texture, microstructure and phase proportions. While this instrument has many applications in materials science, it is also of great interest for geology and geophysics. Some applications include: kinetics of reactions, structure of silicate glasses and melts, high-pressure investigations of complex systems, evolution of texture and anisotropy during deformation and recrystallization. The Lujan Center aims at creating an instrument with high data through-put and easy access to researchers and students. While the HIPPO instrument will be part of the national user facility operated by the Lujan Center, the scientific program will be guided by the University of California consortium with the goal of satisfying national priorities and establishing an environment of scientific excellence. (author)

  14. Role of phase matching in pulsed second-harmonic generation: Walk-off and phase-locked twin pulses in negative-index media

    International Nuclear Information System (INIS)

    The present investigation is concerned with the study of pulsed second-harmonic generation under conditions of phase and group velocity mismatch, and generally low conversion efficiencies and pump intensities. In positive-index, nonmetallic materials, we generally find qualitative agreement with previous reports regarding the presence of a double-peaked second harmonic signal, which comprises a pulse that walks off and propagates at the nominal group velocity one expects at the second-harmonic frequency, and a second pulse that is 'captured' and propagates under the pump pulse. We find that the origin of the double-peaked structure resides in a phase-locking mechanism that characterizes not only second-harmonic generation, but also χ(3) processes and third-harmonic generation. The phase-locking mechanism that we describe occurs for arbitrarily small pump intensities, and so it is not a soliton effect, which usually relies on a threshold mechanism, although multicolor solitons display similar phase locking characteristics. Thus, in second harmonic generation a phase-matched component is always generated, even under conditions of material phase mismatch: This component is anomalous, because the material does not allow energy exchange between the pump and the second-harmonic beam. On the other hand, if the material is phase matched, phase locking and phase matching are indistinguishable, and the conversion process becomes efficient. We also report a similar phase-locking phenomenon in negative index materials. A spectral analysis of the pump and the generated signals reveals that the phase-locking phenomenon causes the forward moving, phase-locked second-harmonic pulse to experience the same negative index as the pump pulse, even though the index of refraction at the second-harmonic frequency is positive. Our analysis further shows that the reflected second-harmonic pulse generated at the interface and the forward-moving, phase-locked pulse appear to be part of the

  15. High thermoelectric performance of niobium-doped strontium titanate bulk material affected by all-scale grain boundary and inclusions

    International Nuclear Information System (INIS)

    The large thermal conductivity of SrTiO3 bulk material limits its potential application for high-temperature thermoelectricity. The effects of all-scale grain boundaries and inclusions on the thermoelectric performance of Nb-doped bulk SrTiO3 materials are investigated in this study. Nano- to microscale grain boundaries and inclusions reduce the thermal conductivity by 30%. As a result, the ZT value is enhanced 2.6 times by a combination of all-sized crystals, energy filtering effect, multilevel scattering behaviors of nano/microscale grain boundaries and inclusions

  16. Nanoscale Phase Immiscibility in High-ZT Bulk Lead Telluride Thermoelectric Materials

    Science.gov (United States)

    Girard, Steven Neal

    Renewable energy initiatives have increased interest in thermoelectric materials as an option for inexpensive and environmentally friendly waste heat-to-power generation. Unfortunately, low efficiencies have limited their wide-scale utilization. This work describes the synthesis and characterization of bulk nanostructured thermoelectric materials wherein natural phase immiscibility is manipulated to selectively generate nanoscale inclusions of a second phase that improve their efficiency through reductions in lattice thermal conductivity. The PbTe-PbS system exhibits natural phase separation by nucleation and growth or spinodal decomposition phase transformations depending on composition and temperature treatment. Through rapid quenching, nearly ideal solid solution alloys of PbTe-PbS are observed by powder X-ray diffraction. However, characterization by solid-state NMR and IR reflectivity show that solid solutions are obtained for rapidly quenched samples within the nucleation and growth region of the phase diagram, but samples within the spinodal decomposition region exhibit very slight phase immiscibility. We report the temperatures of phase separation using high temperature powder X-ray diffraction. Microscopy reveals that phase separation in PbTe-PbS naturally produces nanoinclusions. A decrease in lattice thermal conductivity is observed as a result of the solid solution-to-nanostructured phase transformation in this materials system, increasing thermoelectric figure of merit. Sn addition to PbTe-PbS produces a pseudobinary system of PbTe-PbSnS 2. This materials system produces microscale lamellae that effectively reduce lattice thermal conductivity. Unfortunately, the PbSnS2 inclusions also scatter electrons, reducing electrical conductivity and producing only a minimal increase in thermoelectric figure of merit. We additionally investigate PbSnS2 as prepared through Bridgman crystal growth. PbTe-PbS doped with Na appears to increase the kinetic rate of

  17. Plasmon Injection to Compensate and Control Losses in Negative Index Metamaterials

    CERN Document Server

    Sadatgol, Mehdi; Yang, Lan; Güney, Durdu Ö

    2015-01-01

    Metamaterials have introduced a whole new world of unusual materials with functionalities that cannot be attained in naturally occurring material systems by mimicking and controlling the natural phenomena at subwavelength scales. However, the inherent absorption losses pose fundamental challenge to the most fascinating applications of metamaterials. Based on a novel plasmon injection (PI or \\Pi) scheme, we propose a coherent optical amplification technique to compensate losses in metamaterials. Although the proof of concept device here operates under normal incidence only, our proposed scheme can be generalized to arbitrary form of incident waves. The \\Pi-scheme is fundamentally different than major optical amplification schemes. It does not require gain medium, interaction with phonons, or any nonlinear medium. The \\Pi-scheme allows for loss-free metamaterials. It is ideally suited for mitigating losses in metamaterials operating in the visible spectrum and is scalable to other optical frequencies. These fin...

  18. ES-3100: a new generation shipping container for bulk highly enriched uranium and other fissile materials

    International Nuclear Information System (INIS)

    The U.S. Department of Energy (DOE) National Nuclear Security Administration (NNSA) is shipping bulk quantities of surplus fissile materials, primarily highly enriched uranium (HEU), over the next 15 to 20 years for disposition purposes. The U.S. Department of Transportation (DOT) specification 6M container is the package of choice for most of these shipments. However, the 6M does not conform to the Type B packaging requirements in the Code of Federal Regulations (10CFR711) and, for that reason, is being phased out for use in the secure transportation system of DOE. BWXT Y-12 is currently developing a package to replace the DOT 6M container for HEU disposition shipping campaigns. The new package is based on state-of-the-art, proven, and patented insulation technologies that have been successfully applied in the design of other packages. The new package, designated the ES-3100, will have a 50% greater capacity for HEU than the 6M and will be easier to use. Engineering analysis on the new package includes detailed dynamic impact finite element analysis (FEA). This analysis gives the ES-3100 a high probability of complying with regulatory requirements

  19. Novel Numerical Technique Employed in Accurate Simulations on White-Light Generation in Bulk Material

    CERN Document Server

    Zia, Haider

    2016-01-01

    An accurate simulation has been devised, employing a new numerical technique to simulate the generalised non-linear Schr\\"odinger equation in all three spatial dimensions and time. The simulations model all pertinent higher order effects such as self-steepening and plasma for the non-linear propagation of ultrafast optical radiation in bulk material. Simulation results are accurate and the novel numerical technique uses reduced computational resources. Simulation results are compared to published experimental data of an example ytterbium aluminum garnet (YAG) system at 3.1um radiation and fits to within a factor of 5. The simulation shows that there is a stability point near the end of the 2 mm crystal where the pulse is both collimated at a reduced diameter (factor of ~2) and there exists a near temporal soliton at the optical center. The temporal intensity profile within this stable region is compressed by a factor of ~4 compared to the input. This explains the reported stable regime found in the experiment...

  20. Bulk Nanostructured Materials Obtained by Shock Waves Compaction of Ultrafine Titanium and Aluminum

    Science.gov (United States)

    Chikhradze, Nikoloz M.; Politis, Constantin; Chikhradze, Mikheil; Oniashvili, George

    Theoretical and experimental Investigations of shock wave consolidation processes of Ti-Al nano sized and ultra-disperse powder compositions are discussed. For theoretical calculations of the shock wave loaded materials were used the hydrodynamic theory and experimental adiabatic of Ti and Al. The normal and tangential stresses in the cylindrical steel tube (containers of Ti-Al reaction mixtures) were estimated using the partial solutions of elasticity theory. The mixtures of ultra-disperse Ti and nano sized (≤ 50nm) Al powder compositions were consolidated to full or near-full density by explosive-compaction technology. The ammonium nitride based industrial explosives were used for generation of shock waves. To form ultra-fine grained bulk TiAl intermetallics with different compositions, ultra-disperse Ti particles were mixed with nano-crystalline Al. Each reaction mixture was placed in a sealed container and explosively compacted using a normal and cylindrical detonation set-up. Explosive compaction experiments were performed in range of pressure impulse (5-20) GPa. X-ray diffraction (XRD), structural investigations (SEM) and micro-hardness measurements were used to characterize the intermetallics phase composition and mechanical properties. The results of analysis revealing the effects of the compacting conditions and precursor particles sizes, affecting the consolidation and the properties of this new ultra high performance alloys are discussed.

  1. Feasibility of introducing ferromagnetic materials to onboard bulk high-Tc superconductors to enhance the performance of present maglev systems

    International Nuclear Information System (INIS)

    Highlights: ► Ferromagnetic materials guide the flux distribution of the PMG to bulk positions. ► With ferromagnetic materials, guidance performance can be enhanced greatly. ► A new HTS Maglev system with onboard ferromagnetic materials is designed. ► The design can meet large guidance force requirements for practical applications. -- Abstract: Performance improvement is a long-term research task for the promotion of practical application of promising high-temperature superconducting (HTS) magnetic levitation (maglev) vehicle technologies. We studied the feasibility to enhance the performance of present HTS Maglev systems by introducing ferromagnetic materials to onboard bulk superconductors. The principle here is to make use of the high magnetic permeability of ferromagnetic materials to alter the flux distribution of the permanent magnet guideway for the enhancement of magnetic field density at the position of the bulk superconductors. Ferromagnetic iron plates were added to the upper surface of bulk superconductors and their geometric and positioning effects on the maglev performance were investigated experimentally. Results show that the guidance performance (stability) was enhanced greatly for a particular setup when compared to the present maglev system which is helpful in the application where large guidance forces are needed such as maglev tracks with high degrees of curves

  2. Plasmonic interaction of light with negative index and gold nano-checkerboards

    CERN Document Server

    Chakrabarti, Sangeeta; Shukla, Neeraj; Guenneau, Fanny; Kadic, Muamer; Guenneau, Sebastien; Enoch, Stefan

    2011-01-01

    Negative refractive index materials (NRIM) make possible unique effects such as a convergent at lens due to the reversed Snell-Descartes laws of refraction. NRIM are also known to be able to support a host of surface plasmon states for both polarizations of light which are responsible for the sub-wavelength image resolution achieved by a slab of NRIM. A generalized lens theorem provides us with a class of spatially varying slab lenses satisfying the prerequisite symmetries to fold the optical space onto itself. This theorem can be derived using powerful tools of transformational optics. A paradigm of such complementary media are checkerboards consisting of alternating cells of positive and negative refractive index that represent a very singular situation in which the local density of modes at the corners are enormously enhanced. We have considered several theoretical and numerical aspects of such structured films including a finite slabs of multi-scale checkerboards of NRIM satisfying the generalized lens th...

  3. Anatase-rutile phase transformation of titanium dioxide bulk material: a DFT + U approach

    Science.gov (United States)

    Vu, Nam H.; Le, Hieu V.; Cao, Thi M.; Pham, Viet V.; Le, Hung M.; Nguyen-Manh, Duc

    2012-10-01

    The anatase-rutile phase transformation of TiO2 bulk material is investigated using a density functional theory (DFT) approach in this study. According to the calculations employing the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional with the Vanderbilt ultrasoft pseudopotential, it is suggested that the anatase phase is more energetically stable than rutile, which is in variance with the experimental observations. Consequently, the DFT + U method is employed in order to predict the correct structural stability in titania from electronic-structure-based total energy calculations. The Hubbard U term is determined by examining the band structure of rutile with various values of U from 3 to 10 eV. At U = 5 eV, a theoretical bandgap for rutile is obtained as 3.12 eV, which is in very good agreement with the reported experimental bandgap. Hence, we choose the DFT + U method (with U = 5 eV) to investigate the transformation pathway using the newly-developed solid-state nudged elastic band (ss-NEB) method, and consequently obtain an intermediate transition structure that is 9.794 eV per four-TiO2 above the anatase phase. When the Ti-O bonds in the transition state are examined using charge density analysis, seven Ti-O bonds (out of 24 bonds in the anatase unit cell) are broken, and this result is in excellent agreement with a previous experimental study (Penn and Banfield 1999 Am. Miner. 84 871-6).

  4. Novel low temperature processing techniques for apatite ceramics and chitosan polymer composite bulk materials and its mechanical properties

    Science.gov (United States)

    Onoki, Takamasa; Nakahira, Atsushi; Tago, Tomoyuki; Hasegawa, Yoshiyuki; Kuno, Tomoaki

    2012-12-01

    A co-precipitation method was used for processing chitosan (CHI)/calcium hydrogen phosphate dehydrate (DCPD) hybrid material. CHI solution was mixed into 1.0-M calcium nitrate solution. CHI/DCPD hybrid material was prepared by the above explained addition of CHI and Ca ion source to 1.0-M diammonium hydrogen phosphate solution. It was observed by transmission electron microscopy that CHI and DCPD were mixed within submicron meter scale. CHI/HA bulk materials derived from the CHI/DCPD hybrid materials were obtained by using a hydrothermal hot-pressing (HHP) method. A pressure of 40 MPa was initially applied to the sample. An HHP autoclave was heated up to 150 °C for 2 h. Modified 3-point bending tests were conducted to obtain an easy estimate of the fracture toughness for the CHI/HA bulk materials made with the HHP method. The critical stress intensity factor Kc of the fabricated CHI/HA bulk materials was enhanced from 0.30 to 0.40 MPam1/2 by the hybridization of CHI into DCPD.

  5. Bulk Combinatorial Synthesis and High Throughput Characterization for Rapid Assessment of Magnetic Materials: Application of Laser Engineered Net Shaping (LENS™)

    Science.gov (United States)

    Geng, J.; Nlebedim, I. C.; Besser, M. F.; Simsek, E.; Ott, R. T.

    2016-07-01

    A bulk combinatorial approach for synthesizing alloy libraries using laser engineered net shaping (LENS™; i.e., 3D printing) was utilized to rapidly assess material systems for magnetic applications. The LENS™ system feeds powders in different ratios into a melt pool created by a laser to synthesize samples with bulk (millimeters) dimensions. By analyzing these libraries with autosampler differential scanning calorimeter/thermal gravimetric analysis and vibrating sample magnetometry, we are able to rapidly characterize the thermodynamic and magnetic properties of the libraries. The Fe-Co binary alloy was used as a model system and the results were compared with data in the literature.

  6. Bulk Combinatorial Synthesis and High Throughput Characterization for Rapid Assessment of Magnetic Materials: Application of Laser Engineered Net Shaping (LENS™)

    Science.gov (United States)

    Geng, J.; Nlebedim, I. C.; Besser, M. F.; Simsek, E.; Ott, R. T.

    2016-04-01

    A bulk combinatorial approach for synthesizing alloy libraries using laser engineered net shaping (LENS™; i.e., 3D printing) was utilized to rapidly assess material systems for magnetic applications. The LENS™ system feeds powders in different ratios into a melt pool created by a laser to synthesize samples with bulk (millimeters) dimensions. By analyzing these libraries with autosampler differential scanning calorimeter/thermal gravimetric analysis and vibrating sample magnetometry, we are able to rapidly characterize the thermodynamic and magnetic properties of the libraries. The Fe-Co binary alloy was used as a model system and the results were compared with data in the literature.

  7. Phonons of single quintuple Bi 2 Te 3 and Bi 2 Se 3 films and bulk materials

    KAUST Repository

    Cheng, Wei

    2011-03-10

    Phonons of single quintuple films of Bi2Te3 and Bi2Se3 and corresponding bulk materials are calculated in detail by MedeA (a trademark of Materials Design) and Vienna ab initio simulation package (VASP). The calculated results with and without spin-orbit couplings are compared, and the important roles that the spin-orbit coupling plays in these materials are discussed. A symmetry breaking caused by the anharmonic potentials around Bi atoms in the single quintuple films is identified and discussed. The observed Raman intensity features in Bi 2Te3 and Bi2Se3 quintuple films are explained. © 2011 American Physical Society.

  8. Superconductors, analysis and applications, with special reference to the utilisation of bulk (Re)BCO materials

    Energy Technology Data Exchange (ETDEWEB)

    Coombs, T.A., E-mail: tac1000@cam.ac.u [University of Cambridge, Department of Engineering, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

    2010-11-01

    The Electrical Power and Energy Conversion (EPEC) superconductivity group at Cambridge University has been working on the application of superconductivity to large scale devices. This work is taking place over a range of areas which cover FCLs, motors and generators, SMES, accelerator magnets and MRI. The research is underpinned by advanced modelling techniques using both pure Critical State models and E-J models to analyse the behaviour of the superconductors. As part of the device design we are concentrating on the analysis of AC losses in complicated geometries such as are found in motor windings and the magnetisation of bulk superconductors to enable their full potential to be realised. We are interested in the full range of high-temperature superconductors and have measured and predicted the performance of YBCO, MgB{sub 2} and BSCCO at a range of temperatures and in wire, tape and bulk forms. This paper concentrates on recent work which includes: modelling of coils using formulations based on H and A. A critical state model for the analysis of coils in SMES; crossed field effects in bulk superconductors; a magnetic model together with experimental results which explain and describe the method of flux pumping whereby a bulk superconductor can be magnetised to a high flux density using a repeatedly applied field of low flux density and finally a new configuration for MRI magnets

  9. Superconductors, analysis and applications, with special reference to the utilisation of bulk (Re)BCO materials

    Science.gov (United States)

    Coombs, T. A.

    2010-11-01

    The Electrical Power and Energy Conversion (EPEC) superconductivity group at Cambridge University has been working on the application of superconductivity to large scale devices. This work is taking place over a range of areas which cover FCLs, motors and generators, SMES, accelerator magnets and MRI. The research is underpinned by advanced modelling techniques using both pure Critical State models and E- J models to analyse the behaviour of the superconductors. As part of the device design we are concentrating on the analysis of AC losses in complicated geometries such as are found in motor windings and the magnetisation of bulk superconductors to enable their full potential to be realised. We are interested in the full range of high-temperature superconductors and have measured and predicted the performance of YBCO, MgB 2 and BSCCO at a range of temperatures and in wire, tape and bulk forms. This paper concentrates on recent work which includes: modelling of coils using formulations based on H and A. A critical state model for the analysis of coils in SMES; crossed field effects in bulk superconductors; a magnetic model together with experimental results which explain and describe the method of flux pumping whereby a bulk superconductor can be magnetised to a high flux density using a repeatedly applied field of low flux density and finally a new configuration for MRI magnets

  10. Low-pressure plasma-etching of bulk polymer materials using gas mixture of CF4 and O2

    Directory of Open Access Journals (Sweden)

    Hirofumi Nabesawa

    2013-11-01

    Full Text Available In this study, we have proposed a low-pressure reactive ion etching of bulk polymer materials with a gas mixture of CF4 and O2, and have achieved precise fabrication of poly(methyl methacrylate (PMMA and perfluoroalkoxy (PFA bulk polymer plates with high-aspect-ratio and narrow gap array structures, such as, pillar, frustum, or cone, on a nano/micro scale. The effects of the etching conditions on the shape and size of each pillar were evaluated by changing etching duration and the size/material of etching mask. The fabricated PMMA array structures indicate possibilities of optical waveguide and nanofiber array. PFA cone array structures showed super-hydrophobicity without any chemical treatments. Also, polystyrene-coated silica spheres were used as an etching mask for the pillar array structure formation to control the gap between pillars.

  11. Bulk and interfacial thermal transport in microstructural porous materials with application to fuel cells

    OpenAIRE

    Sadeghifar, Hamidreza

    2015-01-01

    The performance, reliability and durability of fuel cells are strongly influenced by the operating conditions, especially temperature and compression. Adequate thermal and water management of fuel cells requires knowledge of the thermal bulk and interfacial resistances of all involved components. The porous, brittle and anisotropic nature of most fuel cell components, together with the micro/nano-sized structures, has made it challenging to study their transport properties and thermal behavio...

  12. Estimation of Tadalafil Using Derivative Spectrophotometry in Bulk Material and in Pharmaceutical Formulation

    OpenAIRE

    Khan, Zamir G.; Patil, Amod S.; Atul A. Shirkhedkar

    2014-01-01

    Four simple, rapid, accurate, precise, reliable, and economical UV-spectrophotometric methods have been proposed for the determination of tadalafil in bulk and in pharmaceutical formulation. “Method A” is first order derivative UV spectrophotometry using amplitude, “method B” is first order derivative UV spectrophotometry using area under curve technique, “method C” is second order derivative UV spectrophotometry using amplitude, and “method D” is second order derivative UV spectrophotometry ...

  13. Bond strength of a calcium silicate-based sealer tested in bulk or with different main core materials

    OpenAIRE

    Nagas, Emre; Cehreli, Zafer; Mehmet Ozgur UYANIK; Veli DURMAZ

    2014-01-01

    The aim of this study was to evaluate the influence of a calcium silicate-based sealer (iRoot SP), with or without a core material, on bond strength to radicular dentin, in comparison with various contemporary root filling systems. Root canals of freshly extracted single-rooted teeth (n = 60) were instrumented using rotary instruments. The roots were randomly assigned to one of the following experimental groups: (1) a calcium silicate-based sealer without a core material (bulk-fill); (2) a ca...

  14. Grain size effect on electrical resistivity of bulk nanograined Bi{sub 2}Te{sub 3} material

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Oleg, E-mail: olniv@mail.ru; Maradudina, Oxana; Lyubushkin, Roman

    2015-01-15

    The bulk nanograined Bi{sub 2}Te{sub 3} material with various mean grain sizes changing from ~ 97 nm to ~ 51 nm was prepared by microwave assisted solvothermal method and hot pseudo-isostatic pressure. It was found that the specific electrical resistivity of the material increases as mean grain size decreases. Such kind of the grain effect on the resistivity can be attributed to enhanced electron scattering at the grain boundaries. The Mayadas–Shatzkes model was applied to explain experimental results. In this model the grain boundaries are regarded as potential barriers which have to be overcome by the electrons. The reflectivity R of the grain boundaries for the material under study was estimated to be equal to ~ 0.7. - Highlights: • The bulk nanograined Bi{sub 2}Te{sub 3} material with various mean grain sizes was prepared. • It was found that the electrical resistivity of the material increases as grain size decreases. • The Mayadas–Shatzkes model was applied to explain experimental results. • The reflectivity R of the grain boundaries was estimated to be equal to ~ 0.7.

  15. Recombinant mussel adhesive protein fp-5 (MAP fp-5) as a bulk bioadhesive and surface coating material.

    Science.gov (United States)

    Choi, Yoo Seong; Kang, Dong Gyun; Lim, Seonghye; Yang, Yun Jung; Kim, Chang Sup; Cha, Hyung Joon

    2011-08-01

    Mussel adhesive proteins (MAPs) attach to all types of inorganic and organic surfaces, even in wet environments. MAP of type 5 (fp-5), in particular, has been considered as a key adhesive material. However, the low availability of fp-5 has hampered its biochemical characterization and practical applications. Here, soluble recombinant fp-5 is mass-produced in Escherichia coli. Tyrosinase-modified recombinant fp-5 showed ∼1.11 MPa adhesive shear strength, which is the first report of a bulk-scale adhesive force measurement for purified recombinant of natural MAP type. Surface coatings were also performed through simple dip-coating of various objects. In addition, complex coacervate using recombinant fp-5 and hyaluronic acid was prepared as an efficient adhesive formulation, which greatly improved the bulk adhesive strength. Collectively, it is expected that this work will enhance basic understanding of mussel adhesion and that recombinant fp-5 can be successfully used as a realistic bulk-scale bioadhesive and an efficient surface coating material. PMID:21770718

  16. Bulk metamaterials: Design, fabrication and characterization

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Malureanu, Radu; Alabastri, Alessandro;

    2009-01-01

    Bulk metamaterials claim a lot of attention worldwide. We report about our activity and advances in design, fabrication and characterization of metal-dielectric composites with three-dimensional lattices. The nomenclature of designs exhibiting negative index behaviour in the near infrared include......-layers-thick polymer woodpile photonic crystal. Characterization of such samples before and after metal deposition in the 700 nm 1700 nm range exposes some unpredictable features like an enhanced broadband transmission, which still waits to be explained.......Bulk metamaterials claim a lot of attention worldwide. We report about our activity and advances in design, fabrication and characterization of metal-dielectric composites with three-dimensional lattices. The nomenclature of designs exhibiting negative index behaviour in the near infrared includes...

  17. A Method for Determining Bulk Density, Material Density, and Porosity of Melter Feed During Nuclear Waste Vitrification

    Energy Technology Data Exchange (ETDEWEB)

    Hilliard, Zachary J.; Hrma, Pavel R.

    2016-01-31

    Abstract Glass making efficiency largely depends on heat transfer to reacting glass batch (melter feed), which in turn is influenced by the bulk density (ρb) and porosity (Φ) as functions of temperature (T). Neither b(T) nor Φ(T) functions are readily accessible to direct measurement, but they can be determined based on monitoring the profile area of heated glass batch pellets and material density of batches quenched at various stages of conversion via pycnometry. For the determination of Φb, the bulk volume must be calculated as a function of temperature. This is done via a program constructed in MATLAB which takes an image of a pellet profile at a given temperature and calculates the volume of said pellet. The quenched density measured by pycnometry must be converted to the density at heat treatment temperature. This is done by taking into account the volume change due to thermal expansion/contraction.

  18. Using molecular mechanics to predict bulk material properties of fibronectin fibers.

    Directory of Open Access Journals (Sweden)

    Mark J Bradshaw

    Full Text Available The structural proteins of the extracellular matrix (ECM form fibers with finely tuned mechanical properties matched to the time scales of cell traction forces. Several proteins such as fibronectin (Fn and fibrin undergo molecular conformational changes that extend the proteins and are believed to be a major contributor to the extensibility of bulk fibers. The dynamics of these conformational changes have been thoroughly explored since the advent of single molecule force spectroscopy and molecular dynamics simulations but remarkably, these data have not been rigorously applied to the understanding of the time dependent mechanics of bulk ECM fibers. Using measurements of protein density within fibers, we have examined the influence of dynamic molecular conformational changes and the intermolecular arrangement of Fn within fibers on the bulk mechanical properties of Fn fibers. Fibers were simulated as molecular strands with architectures that promote either equal or disparate molecular loading under conditions of constant extension rate. Measurements of protein concentration within micron scale fibers using deep ultraviolet transmission microscopy allowed the simulations to be scaled appropriately for comparison to in vitro measurements of fiber mechanics as well as providing estimates of fiber porosity and water content, suggesting Fn fibers are approximately 75% solute. Comparing the properties predicted by single molecule measurements to in vitro measurements of Fn fibers showed that domain unfolding is sufficient to predict the high extensibility and nonlinear stiffness of Fn fibers with surprising accuracy, with disparately loaded fibers providing the best fit to experiment. This work shows the promise of this microstructural modeling approach for understanding Fn fiber properties, which is generally applicable to other ECM fibers, and could be further expanded to tissue scale by incorporating these simulated fibers into three dimensional

  19. Determination of H, C, N, O content of bulk materials from neutron-attenuation measurements

    International Nuclear Information System (INIS)

    Several bulk samples ranging from chemical compounds to cereal grains have been nondestructively analyzed through neutron-attenuation measurements. A fast-neutron continuum was produced by an accelerator. Attenuations were measured by pulsed-beam, time-of-flight techniques. Average hydrogen, carbon, nitrogen, and oxygen contents were deduced by comparing attenuations to those measured for pure elements. Statistical precisions of 0.3-0.7 atomic percent were achieved for each element in about 10 min. Comparisons with results of other analysis techniques indicate that similar levels of accuracy are possible, even in the presence of small amounts of heavier elements. (author)

  20. The integration of eis parameters and bulk matrix characteristics in studying reinforced cement-based materials

    NARCIS (Netherlands)

    Koleva, D.A.; Van Breugel, K.

    2011-01-01

    Corrosion in reinforced concrete is a major and costly concern, arising from the higher complexity of involved phenomena on different levels of material science (e.g. electrochemistry, concrete material science) and material properties (macro/micro/ nano). Reinforced cement-based systems (e.g. reinf

  1. The Integration of EIS parameters and bulk matrix characterization in studying reinforced cement-based materials

    NARCIS (Netherlands)

    Koleva, D.A.; Van Breugel, K.

    2012-01-01

    Corrosion in reinforced concrete is a major and costly concern, arising from the higher complexity of involved phenomena on different levels of material science (e.g. electrochemistry, concrete material science) and material properties (macro/micro/ nano). Reinforced cement-based systems (e.g. reinf

  2. First measurements of bulk and shear mechanical loss in optical thin film materials

    Science.gov (United States)

    Abernathy, Matthew; Harry, Gregory; Newport, Jonathan; Fair, Hanna; Hickey, Sam; Grettarsson, Andri; Penn, Steve; LIGO Collaboration

    As advanced gravitational wave detectors come online, and the possibility of the first gravitational wave detection nears, plans for the next generation of gravitational wave detectors are already in the works. These new detectors, and those already planned for the future, are expected to be limited in their most sensitive frequency bands by the Brownian thermal noise generated within the optical thin films used to produce the interferometer mirrors. In order to fully predict the level of this Brownian noise, it is necessary to know the two independent mechanical moduli (Young modulus and Poisson ratio, Bulk and Shear moduli, etc.) as well as their associated mechanical loss parameters. Traditional measurements of the mechanical loss of thin films has measured only one linear combination of these two loss parameters. Here, we present measurements of the bulk and shear mechanical loss of tantalum pentoxide (tantala) thin films made by taking advantage of the differing ratios of elastic deformation in the various resonant modes of a coated silica disc. These results may have immediate implications for the ultimate sensitivity of currently operated gravitational wave detectors.

  3. Thermal conductivity of superconducting joint of Y-Ba-Cu-O bulk materials

    International Nuclear Information System (INIS)

    We have measured the thermal conductivity (κ) of bulk Y-Ba-Cu-O blocks welded with sintered Er-Ba-Cu-O and Y-Ba-Cu-O/Ag at temperatures between 5 and 300 K. For comparison, the thermal conductivity was also measured for melt-textured Y-Ba-Cu-O and Er-Ba-Cu-O. All the samples showed the enhancement of κ at around 50 K, which was commonly observed in high temperature superconductors. The maximum κ values were 90 mW/cm K for both welded Y-Ba-Cu-O and melt-textured Er-Ba-Cu-O and 150 mW/cm K for melt-textured Y-Ba-Cu-O. Such differences have originated from different microstructural features

  4. Doping in controlling the type of conductivity in bulk and nanostructured thermoelectric materials

    Science.gov (United States)

    Fuks, D.; Komisarchik, G.; Kaller, M.; Gelbstein, Y.

    2016-08-01

    Doping of materials for thermoelectric applications is widely used nowadays to control the type of conductivity. We report the results of ab-initio calculations aimed at developing the consistent scheme for determining the role of impurities that may change the type of conductivity in two attractive thermoelectric classes of materials. It is demonstrated that alloying of TiNiSn with Cu makes the material of n-type, and alloying with Fe leads to p-type conductivity. Similar calculations for PbTe with small amount of Na substituting for Pb leads to p-type conductivity, while Cl substituting for Te makes PbTe an n-type material. It is shown also that for nano-grained materials the n-type conductivity should be observed. The effect of impurities segregating to the grain boundaries in nano-structured PbTe is also discussed.

  5. Design of Yagi-Uda antennas based on high-permittivity dielectric bulk materials

    OpenAIRE

    Bueno Díez, Miguel Ángel

    2012-01-01

    [ANGLÈS] Dielectrics are insulators and they might therefore seem to be unlikely materials out of which to try and make antennas, but if they are excited in the right way they can be made to radiate very efficiently. Taking advantage of the properties of dielectric materials, a Yagi-Uda antenna based on a high-permittivity ceramic material operating at 3.68 GHz is described. The three-element array features a simulated directivity of approximately 8 dBi and a front-to-back ratio of 10.5 dB. M...

  6. Time-Resolved Imaging of Material Response Following Laser-Induced Breakdown in the Bulk and Surface of Fused Silica

    International Nuclear Information System (INIS)

    Optical components within high energy laser systems are susceptible to laser-induced material modification when the breakdown threshold is exceeded or damage is initiated by pre-existing impurities or defects. These modifications are the result of exposure to extreme conditions involving the generation of high temperatures and pressures and occur on a volumetric scale of the order of a few cubic microns. The response of the material following localized energy deposition, including the timeline of events and the individual processes involved during this timeline, is still largely unknown. In this work, we investigate the events taking place during the entire timeline in both bulk and surface damage in fused silica using a set of time-resolved microscopy systems. These microscope systems offer up to 1 micron spatial resolution when imaging static or dynamic effects, allowing for imaging of the entire process with adequate temporal and spatial resolution. These systems incorporate various pump-probe geometries designed to optimize the sensitivity for detecting individual aspects of the process such as the propagation of shock waves, near-surface material motion, the speed of ejecta, and material transformations. The experimental results indicate that the material response can be separated into distinct phases, some terminating within a few tens of nanoseconds but some extending up to about 100 microseconds. Overall the results demonstrate that the final characteristics of the modified region depend on the material response to the energy deposition and not on the laser parameters.

  7. Energy relaxation of hot electrons in III-N bulk materials

    International Nuclear Information System (INIS)

    Energy relaxation of the hot electrons in GaN, AlN and InN is investigated and compared based on a simple analytical model with both the hot-phonon effect (HPE) and the nonparabolicity of the conduction band taken into account. The impact of the HPE on the energy relaxation time is estimated by using various optical phonon lifetimes. The calculation results show that for this group of III nitrides, the energy relaxation time first falls rapidly and then saturates with the increasing electron temperature, and is higher at a high electron density. The presence of the HPE slows down the power dissipation and increases the energy relaxation time of the hot electrons of the density 1 × 1018 cm−3 (or 1 × 1019 cm−3) by around one or two orders of magnitude at an electron temperature within 3000 K. In particular, the saturated energy relaxation times are 0.12 ps in the bulk GaN, 22 fs in AlN and 26 fs in InN for an electron density of 1 × 1018 cm−3, which imply a rather weak HPE in the AlGaN and AlInN alloys. (paper)

  8. 49 CFR 173.247 - Bulk packaging for certain elevated temperature materials.

    Science.gov (United States)

    2010-10-01

    ... 101 and IM 102 portable tanks; UN portable tanks; marine portable tanks conforming to 46 CFR part 64... of the packaging material at any temperature within the design temperature range. Stress is... packaging authorized in this section, such equipment must be of a self-reclosing design, must...

  9. Mobility and bulk electron-phonon interaction in two-dimensional materials

    DEFF Research Database (Denmark)

    Gunst, Tue; Brandbyge, Mads; Markussen, Troels;

    2015-01-01

    We present calculations of the phonon-limited mobility in intrinsic n-type monolayer graphene, silicene and MoS2. The material properties, including the electron-phonon interaction, are calculated from first principles. Unlike graphene, the carriers in silicene show strong interaction with the ou...

  10. Collection and characterization of a bulk PM2.5 air particulate matter material for use in reference materials.

    Science.gov (United States)

    Heller-Zeisler, S F; Ondov, J M; Zeisler, R

    1999-01-01

    A contemporary PM2.5 (particulate matter smaller than 2.5 microns aerodynamic diameter) aerosol material from an urban site has been collected for the production of a new standard reference material that will be made available for the development of new PM2.5 air quality standards. Air particulate matter corresponding to the PM2.5 fraction was collected at an established Environmental Protection Agency monitoring site in Baltimore, Maryland. The air-sampling system that has been constructed for this collection separates fine particles with a cyclone separator and deposits them onto an array of Teflon membrane filters. The fine air particulate material is removed by ultrasonication or by mechanical means and collected for further preparation of standards. The composition of the collected PM2.5 aerosol, as well as the composition of the deposited PM2.5 aerosol, are determined by instrumental nuclear activation analysis and other techniques. PMID:10676493

  11. Optimization of sintering conditions in bulk MgB{sub 2} material for improvement of critical current density

    Energy Technology Data Exchange (ETDEWEB)

    Muralidhar, M., E-mail: miryala1@shibaura-it.ac.jp [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan); Nozaki, K.; Kobayashi, H. [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan); Zeng, X.L.; Koblischka-Veneva, A.; Koblischka, M.R. [Experimental Physics, Saarland University, P.O. Box 151150, 66041 Saarbrücken (Germany); Inoue, K.; Murakami, M. [Superconducting Materials Laboratory, Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan)

    2015-11-15

    The present investigation focuses on methods to further improve the J{sub c} values of disk-shaped bulk MgB{sub 2} superconductors by optimizing the sintering conditions. We prepared two sets of bulk MgB{sub 2} material from commercial high-purity powders of Mg metal and amorphous B using a single-step solid-state reaction process. To optimize the sintering time, a set of samples was sintered at 775 °C with sintering duration ranging between 1 and 10 h (pure Ar atmosphere). A second set of samples was produced similarly at 775, 780, 785, 795, 800 and 805 °C (3 h, pure argon atmosphere). X-ray diffraction analysis showed that both sets of samples were single phase MgB{sub 2}. Magnetization measurements confirmed a sharp superconducting transition with T{sub c,onset} ≈ 38.2 K–38.8 K. The critical current density (J{sub c}) values for MgB{sub 2} samples produced for 1 h were the highest in all processed materials, i.e., the high J{sub c} value of 270,000 A/cm{sup 2} and 125,000 A/cm{sup 2} (20 K, self-field and 1 T) were achieved in the sample produced at 775 °C, without any additional doping. In contrast, the second series of samples clearly indicated that at 805 °C (3 h) the highest J{sub c} of 245,000 A/cm{sup 2} and 110,000 A/cm{sup 2} (20 K, self-field and 1 T) were achieved. AFM and EBSD observations indicated that largest amount of fine grains do exist in the sample sintered at 775 °C, but the narrowest distribution of grains does exist in the sample sintered at 800 °C. The present results clearly demonstrate a strong relation between the microstructure and the pinning performance. The optimization of the sintering conditions is crucial to improve the performance of bulk MgB{sub 2} samples. - Highlights: • We had successfully improved the performance of sintered, pure bulk MgB{sub 2} materials. • EBSD observations clarified that the grain sizes are in the 100–500 nm range. • The high J{sub c} value at 20 K, 0 T and 1 T are 2.70 × 10{sup 5} A

  12. Performance Improvement of Bulk Heterojunction Organic Photovoltalc Cell by Addition of a Hole Transport Material

    Institute of Scientific and Technical Information of China (English)

    ZHANG Nan; LIU Qian; MAO Jie; LIU Zun-Feng; YANG Li-Ying; YIN Shou-Gen; CHEN Yong-Sheng

    2008-01-01

    @@ A novel photovoltaic cell with an active layer of poly(phenyleneethynylene)(PPE)/C60/N,N'-diphenyl-N,N'-di-(m-tolyl)-p-benzidine(TPD)is designed.In the active layer,PPE is the major component;C60 and TPD are the minor ones.Compared with a control BHJ device based on PPE/C60,the short circuit current density Jsc is increased by 1 order of magnitude,and the whole device performance is increased greatly,however the open circuit voltage Voc is largely decreased.The possible mechanism of the improved performance may be as follows:In the PPE/C60/TPD device,PPE,C60,and TPD serve as the energy harvesting material,the electron transport material,and the hole transport materiall respectively.As the TPD and C60 are spatially separated by PPE,the charge recombination is effectively retarded.

  13. Neutron beam measurement of industrial polymer materials for composition and bulk integrity

    International Nuclear Information System (INIS)

    Neutron beam techniques, among other non-destructive diagnostics, are particularly irreplaceable in the complete analysis of industrial materials and components when supplying fundamental information. In this paper, nanoscale small-angle neutron scattering analysis and prompt gamma activation analysis for the characterization of industrial polymers are considered. The basic theoretical aspects are briefly introduced and some applications are presented. The investigations of the SU-8 polymer in axial airflow microturbines—i.e. microelectromechanical systems—are presented foremost. Also presented are full and feasibility studies on polyurethanes, composites based on cross-linked polymers reinforced by carbon fibres and polymer cement concrete. The obtained results have provided a substantial contribution to the improvement of the considered materials, and indeed confirmed the industrial applicability of the adopted techniques in the analysis of polymers. (paper)

  14. Band structures tunability of bulk 2D phononic crystals made of magneto-elastic materials

    Directory of Open Access Journals (Sweden)

    J. O. Vasseur

    2011-12-01

    Full Text Available The feasibility of contactless tunability of the band structure of two-dimensional phononic crystals is demonstrated by employing magnetostrictive materials and applying an external magnetic field. The influence of the amplitude and of the orientation with respect to the inclusion axis of the applied magnetic field are studied in details. Applications to tunable selective frequency filters with switching functionnality and to reconfigurable wave-guides and demultiplexing devices are then discussed.

  15. CuAlTe{sub 2}: A promising bulk thermoelectric material

    Energy Technology Data Exchange (ETDEWEB)

    Gudelli, Vijay Kumar [Department of Physics, Indian Institute of Technology Hyderabad, Ordnance Factory Estate, Yeddumailaram 502 205, Telangana (India); Kanchana, V., E-mail: kanchana@iith.ac.in [Department of Physics, Indian Institute of Technology Hyderabad, Ordnance Factory Estate, Yeddumailaram 502 205, Telangana (India); Vaitheeswaran, G. [Advanced Centre of Research in High Energy Materials (ACRHEM), University of Hyderabad, Prof. C. R. Rao Road, Gachibowli, Hyderabad 500 046, Telangana (India)

    2015-11-05

    Transport properties of Cu-based chalcopyrite materials are presented using the full potential linear augmented plane wave method and Boltzmann Semi-classical theory. All the studied compounds appear to be direct band gap semiconductors evaluated based on the Tran-Blaha modified Becke-Johnson potential. The heavy and light band combination found near the valence band maximum (VBM) drive these materials to possess good thermoelectric properties. Among the studied compounds, CuAlTe{sub 2} is found to be more promising, in comparison with CuGaTe{sub 2}, which is reported to be an efficient thermoelectric material with appreciable figure of merit. Another interesting fact about CuAlTe{sub 2} is the comparable thermoelectric properties possessed by both n- type and p-type carriers, which might attract good device applications and are explained in detail using the electronic structure calculations. - Highlights: • Band structure calculation of Cu(Al,Ga)Ch{sub 2} compounds with the TB-mBJ functional. • Mixed heavy-light bands near Fermi level might favour good thermoelectric properties. • Among the investigated compounds CuAlTe{sub 2} appears to be more promising. • Thermoelectric properties of CuAlTe{sub 2} are almost comparable with CuGaTe{sub 2}. • Both n,p-type thermoelectric properties of CuAlTe{sub 2} can attract device applications.

  16. Effect of Doping on beta-Tricalcium Phosphate Bioresorbable Bulk Material and Thin Film Coatings

    Science.gov (United States)

    Abdalla, Suhaila

    Magnesium has emerged as a revolutionary biodegradable metal for use as an orthopedic material, it has several advantages over the current metallic materials in use, including eliminating the effects of stress shielding, improving biocompatibility and inhibiting degradation rates, thus removing the requirement of a second surgery for implant removal. Due to the rapid degradation of magnesium, it is necessary to control the corrosion rates of the materials to match the rates of bone healing. This dissertation reports on the effect of doping on the properties of beta-tricalcium phosphate (beta-TCP). It also reports on its application as a thin film coating on magnesium alloys for implant applications. Adding various dopants to beta-TCP significantly influences critical properties. In this study, discs were fabricated in two compositions: (i) undoped beta-TCP, (ii) beta-TCP doped with 1.0 wt % MgO, 0.5 wt % ZnO, and 1.0 wt % TiO2. Films were fabricated from these compositions using the pulsed laser deposition (PLD) technique. These coatings were then characterized for corrosive, hardness, and cytocompatibility. The XRD patterns of the coating confirm the amorphous nature of the films. The presence of the metal oxides in beta-TCP improved ceramic densification. The application of these doped coatings was also found to increase the hardness by 88 %, the modulus of elasticity by 66 %, and improve corrosion resistance of the magnesium alloy substrate; with a 2.4 % improvement in Ecorr and 95 % decrease in icorr. Cell viability was studied using an osteoblast precursor cell line MC3T3-E1 to assure that the biocompatibility of these ceramics was not altered due to the dopants. Long-term biodegradation studies were conducted by measuring weight change and surface microstructure as a function of time in simulated body fluid. The results suggest that these coatings could be used for bioresorbable implants with improved corrosion resistance and increased hardness.

  17. Large difference between the magnetic properties of Ba and Ti co-doped BiFeO3 bulk materials and their corresponding nanoparticles prepared by ultrasonication

    Science.gov (United States)

    Ahmmad, Bashir; Kanomata, Kensaku; Koike, Kunihiro; Kubota, Shigeru; Kato, Hiroaki; Hirose, Fumihiko; Billah, Areef; Jalil, M. A.; Basith, M. A.

    2016-07-01

    The ceramic pellets of the nominal compositions Bi0.7Ba0.3Fe1‑x Ti x O3 (x  =  0.00–0.20) were prepared initially by standard solid state reaction technique. The pellets were then ground into micrometer-sized powders and mixed with isopropanol in an ultrasonic bath to prepare nanoparticles. The x-ray diffraction patterns demonstrate the presence of a significant number of impurity phases in bulk powder materials. Interestingly, these secondary phases were completely removed due to the sonication of these bulk powder materials for 60 minutes. The field and temperature dependent magnetization measurements exhibited significant difference between the magnetic properties of the bulk materials and their corresponding nanoparticles. We anticipate that the large difference in the magnetic behavior may be associated with the presence and absence of secondary impurity phases in the bulk materials and their corresponding nanoparticles, respectively. The leakage current density of the bulk materials was also found to suppress in the ultrasonically prepared nanoparticles compared to that of bulk counterparts.

  18. Bulk moisture determination in building materials by fast neutron/gamma technique

    International Nuclear Information System (INIS)

    Fast Neutron/Gamma Transmission technique has been improved to allow to measure moisture content in building materials. In order to improve fast neutron/gamma discrimination in the transmission system employing the NE-213 scintillation detector a pulse shape discrimination system was constructed at the CEADEN. A separate neutron/gamma detection approach was used with neutron transmission measurement using an Am-Be neutron source and a BF3 detector and gamma transmission measurement using a collimated 137Cs source and a NaI scintillator

  19. A Validated TLC-Densitometric Method for the Determination of Mesterolone in Bulk Material and in Tablets

    Science.gov (United States)

    Dołowy, Małgorzata; Pyka-Pająk, Alina; Filip, Katarzyna; Zagrodzka, Joanna

    2015-01-01

    Mesterolone is a synthetic androgenic steroid indicating a weak anabolic activity. A new, simple in use, and economical TLC-densitometric method in normal phase system (NP-TLC) has been developed and validated for the identification and quantitative determination of mesterolone in bulk drug and in tablet formulation. NP-TLC analysis was performed on aluminium plates precoated with silica gel 60F254 as the stationary phase using chloroform-acetone (40 : 10, v/v) as mobile phase. Densitometric analysis was carried out at λ = 745 nm after staining with phosphomolybdic acid. These conditions were found to give visible (dark blue) spot and sharp peak, respectively, for mesterolone at RF  0.75 ± 0.02 and enabled satisfactory separation of mesterolone from its related substance (potential impurity). The proposed NP-TLC-densitometric method was validated for specificity, linearity, precision, accuracy, robustness, and sensitivity according to ICH guideline and other validation requirements. The limit of detection (LOD) and limit of quantification (LOQ) were 61.0 ng·spot−1 and 184.0 ng·spot−1, respectively. The percent content of mesterolone in marketed tablet formulation was found to be 99.40% of label claim. The developed TLC-densitometric method can be successfully used in quality control of mesterolone in bulk material and also tablet formulation. PMID:26881196

  20. A Negative Index Metamaterial-Inspired UWB Antenna with an Integration of Complementary SRR and CLS Unit Cells for Microwave Imaging Sensor Applications.

    Science.gov (United States)

    Islam, Mohammad Tariqul; Islam, Md Moinul; Samsuzzaman, Md; Faruque, Mohammad Rashed Iqbal; Misran, Norbahiah

    2015-01-01

    This paper presents a negative index metamaterial incorporated UWB antenna with an integration of complementary SRR (split-ring resonator) and CLS (capacitive loaded strip) unit cells for microwave imaging sensor applications. This metamaterial UWB antenna sensor consists of four unit cells along one axis, where each unit cell incorporates a complementary SRR and CLS pair. This integration enables a design layout that allows both a negative value of permittivity and a negative value of permeability simultaneous, resulting in a durable negative index to enhance the antenna sensor performance for microwave imaging sensor applications. The proposed MTM antenna sensor was designed and fabricated on an FR4 substrate having a thickness of 1.6 mm and a dielectric constant of 4.6. The electrical dimensions of this antenna sensor are 0.20 λ × 0.29 λ at a lower frequency of 3.1 GHz. This antenna sensor achieves a 131.5% bandwidth (VSWR sensors. PMID:26007721

  1. A confocal rheoscope to study bulk or thin-film material under uniaxial or biaxial shear

    CERN Document Server

    Lin, Neil Y C; Cheng, Xiang; Leahy, Brian; Cohen, Itai

    2016-01-01

    We present a new design of a confocal rheoscope that enables us to precisely impose a uniform uniaxial or biaxial shear. The design consists of two precisely-positioned parallel plates. Our design allows us to adjust the gap between the plates to be as small as 2$\\pm$0.1 $\\mu$m, allowing for the exploration of confinement effects. By using our shear cell in conjunction with a biaxial force measurement device and a high-speed confocal microscope, we are able to measure the real-time biaxial stress while simultaneously imaging the material 3D structure. We illustrate the importance of the instrument capabilities by discussing the applications of this instrument in current and future research topics in colloidal suspensions.

  2. Microwave resonant technique in studies of photodielectric properties of bulk, thin film and nanoparticle materials

    Science.gov (United States)

    Pavlov, V. V.; Rakhmatullin, R. M.; Cefalas, A. C.; Semashko, V. V.

    2016-06-01

    An enhanced contactless microwave technique allows us to study the photoconductivity of materials. The transient response of the complex permittivity of matter (ε ={ε1}-j{ε2} ) under optical irradiation is measured with nanosecond time resolution. The main advantage of the novel methodology is the elimination of the polarization effect in evaluating photoconductivity. The potential of the methodology was demonstrated by photoconductivity measurements in Si [1 0 0] crystal, CeO2 nanocrystalline powder and Ce-doped LiYF4 single crystal. The variations of complex permittivity (δ {ε1} and δ {ε2} ) of Si [1 0 0] crystal, CeO2 nanocrystalline powder and Ce-doped LiYF4 single crystal under optical irradiation was measured and accurate values for crystalline band gaps were extracted. Finally, quantum confinement effects were observed in nano-size crystalline powders.

  3. A Negative Index Metamaterial-Inspired UWB Antenna with an Integration of Complementary SRR and CLS Unit Cells for Microwave Imaging Sensor Applications

    OpenAIRE

    Mohammad Tariqul Islam; Md. Moinul Islam; Md. Samsuzzaman; Mohammad Rashed Iqbal Faruque; Norbahiah Misran

    2015-01-01

    This paper presents a negative index metamaterial incorporated UWB antenna with an integration of complementary SRR (split-ring resonator) and CLS (capacitive loaded strip) unit cells for microwave imaging sensor applications. This metamaterial UWB antenna sensor consists of four unit cells along one axis, where each unit cell incorporates a complementary SRR and CLS pair. This integration enables a design layout that allows both a negative value of permittivity and a negative value of permea...

  4. A novel in situ device based on a bionic piezoelectric actuator to study tensile and fatigue properties of bulk materials

    International Nuclear Information System (INIS)

    In this work, a miniaturized device based on a bionic piezoelectric actuator was developed to investigate the static tensile and dynamic fatigue properties of bulk materials. The device mainly consists of a bionic stepping piezoelectric actuator based on wedge block clamping, a pair of grippers, and a set of precise signal test system. Tensile and fatigue examinations share a set of driving system and a set of signal test system. In situ tensile and fatigue examinations under scanning electron microscope or metallographic microscope could be carried out due to the miniaturized dimensions of the device. The structure and working principle of the device were discussed and the effects of output difference between two piezoelectric stacks on the device were theoretically analyzed. The tensile and fatigue examinations on ordinary copper were carried out using this device and its feasibility was verified through the comparison tests with a commercial tensile examination instrument

  5. A novel in situ device based on a bionic piezoelectric actuator to study tensile and fatigue properties of bulk materials

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shupeng; Zhang, Zhihui, E-mail: zhzh@jlu.edu.cn; Ren, Luquan; Liang, Yunhong [The Key Laboratory of Engineering Bionics (Ministry of Education) and the College of Biological and Agricultural Engineering, Jilin University (Nanling Campus), 5988 Renmin Street, Changchun 130025 (China); Zhao, Hongwei [College of Mechanical Science and Engineering, Jilin University (Nanling Campus), 5988 Renmin Street, Changchun 130025 (China); Zhu, Bing [College of Automotive Engineering, Jilin University (Nanling Campus), 5988 Renmin Street, Changchun 130025 (China)

    2014-06-15

    In this work, a miniaturized device based on a bionic piezoelectric actuator was developed to investigate the static tensile and dynamic fatigue properties of bulk materials. The device mainly consists of a bionic stepping piezoelectric actuator based on wedge block clamping, a pair of grippers, and a set of precise signal test system. Tensile and fatigue examinations share a set of driving system and a set of signal test system. In situ tensile and fatigue examinations under scanning electron microscope or metallographic microscope could be carried out due to the miniaturized dimensions of the device. The structure and working principle of the device were discussed and the effects of output difference between two piezoelectric stacks on the device were theoretically analyzed. The tensile and fatigue examinations on ordinary copper were carried out using this device and its feasibility was verified through the comparison tests with a commercial tensile examination instrument.

  6. Dynamic ultrafast laser beam tailoring for multispot photo-inscription of photonic devices in bulk transparent materials

    Science.gov (United States)

    Mauclair, C.; Cheng, G.; Huot, N.; Audouard, E.; Rosenfeld, A.; Hertel, I.; Stoian, R.

    2009-02-01

    Femtosecond laser processing of bulk transparent materials can generate localized increase of the refractive index. Thus, translation of the laser spot give potential access to three dimensionnal photowriting of waveguiding structures. Increasing the number of machining foci can considerably reduce the processing efforts when complex photonic structures are envisaged such as waveguide arrays. The present report presents a technique of dynamic ultrafast laser beam spatial tailoring for parallel writing of photonic devices. The wavefront of the beam is modulated by a periodical binary (0-π) phase mask of variable pattern to achieve dynamic multispot operation. The parallel photoinscription of multiple waveguides is demonstrated in fused silica. Using this method, light dividers in three dimensions relying on evanescent coupling are reported and wavelength-division demultiplexing (WDD) devices were achieved in single sample scan.

  7. A novel in situ device based on a bionic piezoelectric actuator to study tensile and fatigue properties of bulk materials

    Science.gov (United States)

    Wang, Shupeng; Zhang, Zhihui; Ren, Luquan; Zhao, Hongwei; Liang, Yunhong; Zhu, Bing

    2014-06-01

    In this work, a miniaturized device based on a bionic piezoelectric actuator was developed to investigate the static tensile and dynamic fatigue properties of bulk materials. The device mainly consists of a bionic stepping piezoelectric actuator based on wedge block clamping, a pair of grippers, and a set of precise signal test system. Tensile and fatigue examinations share a set of driving system and a set of signal test system. In situ tensile and fatigue examinations under scanning electron microscope or metallographic microscope could be carried out due to the miniaturized dimensions of the device. The structure and working principle of the device were discussed and the effects of output difference between two piezoelectric stacks on the device were theoretically analyzed. The tensile and fatigue examinations on ordinary copper were carried out using this device and its feasibility was verified through the comparison tests with a commercial tensile examination instrument.

  8. Optimizing the equal channel angular pressing process (ECAP) operation parameters to produce bulk nanostructure materials

    Science.gov (United States)

    Abushgair, K.

    2015-03-01

    In this work we were interested in doing simulation using finite elements analysis (FEA) to study the equal channel angular pressing process (ECAP), which is currently one of the most popular methods of severe plastic deformation Processes (SPD). for fabricating Ultra-Fine Grained (UFG) materials, because it allows very high strains to be imposed leading to extreme work hardening and microstructural refinement. The main object of this study is to establish the influence of main parameters which effect ECAP process which are magnitude of the die angle and the friction coefficient. The angle studied between (90-135°) degree, and magnitude of the friction coefficient μ between (0.12-0.6), and number of pass. The samples were made from aluminum alloy at room temperature with (15X 15) mm cross section and 150 mm length. The simulation result shows that normal elastic strain, shears elastic strain, and max. shear elastic strain increased, when changing the angle from 90° to 100°. and decrease between the angle 110° to 135°. Also the total deformation increased when we change die angle from 90° to 135°. By studding the friction effect on the die and sample we noted that increasing the friction coefficient from 0.12 to 0.6, normal elastic strain, and shear elastic strain increased and increasing the friction coefficient from 0.1 to 0.6 decrease the normal and shear stress.

  9. Development of the Algorithm for Energy Efficiency Improvement of Bulk Material Transport System

    Directory of Open Access Journals (Sweden)

    Milan Bebic

    2013-06-01

    Full Text Available The paper presents a control strategy for the system of belt conveyors with adjustable speed drives based on the principle of optimum energy consumption. Different algorithms are developed for generating the reference speed of the system of belt conveyors in order to achieve maximum material cross section on the belts and thus reduction of required electrical drive power. Control structures presented in the paper are developed and tested on the detailed mathematical model of the drive system with the rubber belt. The performed analyses indicate that the application of the algorithm based on fuzzy logic control (FLC which incorporates drive torque as an input variable is the proper solution. Therefore, this solution is implemented on the newvariable speed belt conveyor system with remote control on an open pit mine. Results of measurements on the system prove that the applied algorithm based on fuzzy logic control provides minimum electrical energy consumption of the drive under given constraints. The paper also presents the additional analytical verification of the achieved results trough a method based on the sequential quadratic programming for finding a minimum of a nonlinear function of multiple variables under given constraints.

  10. Optimizing the equal channel angular pressing process (ECAP) operation parameters to produce bulk nanostructure materials

    Energy Technology Data Exchange (ETDEWEB)

    Abushgair, K. [Khaleel. Abu-Shgair, Al-Balqa Applied University, Amman, Jordan. khaleel45@yahoo.com (Jordan)

    2015-03-30

    In this work we were interested in doing simulation using finite elements analysis (FEA) to study the equal channel angular pressing process (ECAP), which is currently one of the most popular methods of severe plastic deformation Processes (SPD). for fabricating Ultra-Fine Grained (UFG) materials, because it allows very high strains to be imposed leading to extreme work hardening and microstructural refinement. The main object of this study is to establish the influence of main parameters which effect ECAP process which are magnitude of the die angle and the friction coefficient. The angle studied between (90-135°) degree, and magnitude of the friction coefficient μ between (0.12-0.6), and number of pass. The samples were made from aluminum alloy at room temperature with (15X 15) mm cross section and 150 mm length. The simulation result shows that normal elastic strain, shears elastic strain, and max. shear elastic strain increased, when changing the angle from 90° to 100°. and decrease between the angle 110° to 135°. Also the total deformation increased when we change die angle from 90° to 135°. By studding the friction effect on the die and sample we noted that increasing the friction coefficient from 0.12 to 0.6, normal elastic strain, and shear elastic strain increased and increasing the friction coefficient from 0.1 to 0.6 decrease the normal and shear stress.

  11. Comparison of Customer Preference for Bulk Material Handling Equipment through Fuzzy-AHP Approach

    Science.gov (United States)

    Sen, Kingshuk; Ghosh, Surojit; Sarkar, Bijan

    2016-06-01

    In the present study, customer's perception has played one of the important roles for selection of the exact equipment out of available alternatives. The present study is dealt with the method of optimization of selection criteria of a material handling equipment, based on the technical specifications considered to be available at the user end. In this work, the needs of customers have been identified and prioritized, that lead to the selection of number of criteria, which have direct effect upon the performance of the equipment. To check the consistency of selection criteria, first of all an AHP based methodology is adopted with the identified criteria and available product categories, based upon which, the judgments of the users are defined to derive the priority scales. Such judgments expressed the relative strength or intensity of the impact of the elements of the hierarchy. Subsequently, all the alternatives have ranked for each identified criteria with subsequent constitution of weighted matrices. The same has been compared with the normalized values of approximate selling prices of the equipments to determine individual cost-benefit ratio. Based on the cost-benefit ratio, the equipment is ranked. With same conditions, the study is obtained again with a Fuzzy AHP concept, where a fuzzy linguistic approach has reduced the amount of uncertainty in decision making, caused by conventional AHP due to lack of deterministic approach. The priority vectors of category and criteria are determined separately and multiplied to obtain composite score. Subsequently, the average of fuzzy weights was determined and the preferences of equipment are ranked.

  12. Coercivity and superparamagnetic evolution of high energy ball milled (HEBM) bulk CoFe2O4 material

    International Nuclear Information System (INIS)

    Ball milling (BM) of bulk CoFe2O4 powder material carried out in order to study its structural stability and attendant property changes with respect to coercivity enhancements and superparamagnetic behaviors, showed that drastic crystallite size reduction occurred within the first 1 h of ball milling. Crystallite size dropped from 74 nm for the as-received material to a value of 11.6 nm for 600 min of ball milling. Combined X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses confirmed crystallite size reduction with corresponding increase in interparticle agglomeration/pores with increasing milling time. The maximum coercivity of 0.46 T and the crystallite size of 15.6 nm were recorded with 20 min, while peak residual strain of 0.0066 mm/mm was for 180 min of BM. Material with peak coercivity value did not have peak residual strain, or minimum crystallite size, thereby suggesting that other structural defects contributed to coercivity enhancement. The saturation magnetization (Ms) value decreased continuously with increasing milling time, while remanence magnetization (Mr) and coercivity decreased with increasing BM time, after an initial increase. Moessbauer spectroscopy (MS) measurements confirmed both particle size distribution and decomposition/disordering of the material together with superparamagnetism as BM time increased. The degree of inversion ranged from 41% to 71.7% at different milled states from Moessbauer spectroscopy. The internal magnetic fields of the Fe sites associated with the tetrahedral and octahedral sites were 507.4 kOe and 492 kOe respectively in the unmilled state, while 484 kOe and 468.5 kOe in the 600 min milled state correspondingly.

  13. CMP process optimization using alkaline bulk copper slurry on a 300 mm Applied Materials Reflexion LK system

    International Nuclear Information System (INIS)

    CMP process optimization for bulk copper removal based on alkaline copper slurry was performed on a 300 mm Applied Materials Reflexion LK system. Under the DOE condition, we conclude that as the pressure increases, the removal rate increases and non-uniformity is improved. As the slurry flow rate increases, there is no significant improvement in the material removal rate, but it does slightly reduce the WIWNU and thus improve uniformity. The optimal variables are obtained at a reduced pressure of 1.5 psi and a slurry flow rate of 300 ml/min. Platen/carrier rotary speed is set at a constant value of 97/103 rpm. We obtain optimized CMP characteristics including a removal rate over 6452 Å/min and non-uniformity below 4% on blanket wafer and the step height is reduced by nearly 8000 Å/min in the center of the wafer on eight layers of copper patterned wafer, the surface roughness is reduced to 0.225 nm. (semiconductor technology)

  14. Batch and bulk removal of a triarylmethane dye, Fast Green FCF, from wastewater by adsorption over waste materials

    International Nuclear Information System (INIS)

    De-Oiled Soya, an agricultural waste material and Bottom Ash a waste of power plants, have been used as adsorbents for the removal and recovery of a triarylmethane dye Fast Green FCF from wastewater. Batch studies have been carried by observing the effects of pH, temperature, concentration of the dye, amount of adsorbents, sieve size of adsorbent, contact time, etc. Graphical correlation of various adsorption isotherm models like, Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich have been carried out for both the adsorbents. The adsorption over both the materials has been found endothermic and feasible in nature. Various thermodynamic parameters, such as, Gibb's free energy, entropy and enthalpy of the on-going adsorption process have been calculated. The kinetic studies suggest the process following pseudo first order kinetics and involvement of particle diffusion mechanism. The bulk removal of the dye has been carried out by passing the dye solution through columns of Bottom Ash and De-Oiled Soya and saturation factor of each column has been calculated. Attempts have also been made to recover the dye by eluting dilute NaOH through the columns

  15. Phonon and Raman scattering of two-dimensional transition metal dichalcogenides from monolayer, multilayer to bulk material.

    Science.gov (United States)

    Zhang, Xin; Qiao, Xiao-Fen; Shi, Wei; Wu, Jiang-Bin; Jiang, De-Sheng; Tan, Ping-Heng

    2015-05-01

    Two-dimensional (2D) transition metal dichalcogenide (TMD) nanosheets exhibit remarkable electronic and optical properties. The 2D features, sizable bandgaps and recent advances in the synthesis, characterization and device fabrication of the representative MoS2, WS2, WSe2 and MoSe2 TMDs make TMDs very attractive in nanoelectronics and optoelectronics. Similar to graphite and graphene, the atoms within each layer in 2D TMDs are joined together by covalent bonds, while van der Waals interactions keep the layers together. This makes the physical and chemical properties of 2D TMDs layer-dependent. In this review, we discuss the basic lattice vibrations of 2D TMDs from monolayer, multilayer to bulk material, including high-frequency optical phonons, interlayer shear and layer breathing phonons, the Raman selection rule, layer-number evolution of phonons, multiple phonon replica and phonons at the edge of the Brillouin zone. The extensive capabilities of Raman spectroscopy in investigating the properties of TMDs are discussed, such as interlayer coupling, spin-orbit splitting and external perturbations. The interlayer vibrational modes are used in rapid and substrate-free characterization of the layer number of multilayer TMDs and in probing interface coupling in TMD heterostructures. The success of Raman spectroscopy in investigating TMD nanosheets paves the way for experiments on other 2D crystals and related van der Waals heterostructures. PMID:25679474

  16. Structural, chemical, and thermoelectric properties of Bi2Te3 Peltier materials. Bulk, thin films, and superlattices

    International Nuclear Information System (INIS)

    In this work, the nature of the natural nanostructure (nns) was analysed and the correlations to the transport coefficients, particularly the lattice thermal conductivity, is discussed. Experimental methods are presented for the first time, yielding an accurate quantitative analysis of the chemical composition and of stress fields in Bi2Te3 and in compounds with similar structural and chemical microstructures. This work can be subdivided as follows: (I) N-type Bi2(Te0.91Se0.09)3 and p-type (Bi0.26Sb0.74)1.98(Te0.99Se0.01)3.02 bulk materials synthesised by the Bridgman technique. (II) Bi2Te3 thin films and Bi2Te3/Bi2(Te0.88Se0.12)3 superlattices epitaxially grown by molecular beam epitaxy (MBE) on BaF2 substrates with periods of δ-12 nm at the Fraunhofer-Institut fuer Physikalische Messtechnik (IPM). (III) Experimental methods, i.e., TEM specimen preparation, high-accuracy quantitative chemical analysis by EDX in the TEM, and image simulations of dislocations and the nns according to the two-beam dynamical diffraction theory. The nns was analysed in detail by stereomicroscopy and by image simulation and was found to be a pure sinusoidal displacement field with (i) a displacement vector parallel to and an amplitude of about 10 pm and (ii) a wave vector parallel to {1,0,10} and a wavelength of 10 nm. The results obtained here showed a significant amount of stress in the samples, induced by the nns which was still not noticed and identified. Both kinds of nanostructures, artificial (ans) and natural (nns) nanostructures, yielded in thermoelectric materials a low lattice thermal conductivity which was beneficial for the thermoelectric figure of merit ZT. (orig.)

  17. Preparation of high performance Zn4Sb3 bulk thermoelectric materials%Zn4Sb3高性能热电材料的制备

    Institute of Scientific and Technical Information of China (English)

    陈中春; 辻村润一; 葳本遼

    2011-01-01

    A "reaction -extrusion process" has been developed to prepare Zn4Sb3 bulk materials with high thermoelectric performance. The synthesis, densification, and shape -forming of Zn4Sb3 bulk materials were realized simultaneously in one hot - extrusion process, and the resulting extrudates had high density with single β - Zn4 Sb3phase. A large extrusion ratio and a small punch speed are advantageous to enhance thermoelectric performance. The extruded Zn4Sb3 materials exhibited excellent thermoelectric performance, for example, the dimensionless thermoelectric figure of merit is 1.77 at 623 K, which is 36% higher compared to conventional hot - pressed materials. On the other hand, the incorporation of 1% SiC nanosized particles into Zn4Sb3 matrix leads to improvements in both thermoelectric and mechanical properties.

  18. Effect of residual chips on the material removal process of the bulk metallic glass studied by in situ scratch testing inside the scanning electron microscope

    OpenAIRE

    Hu Huang; Hongwei Zhao; Chengli Shi; Boda Wu; Zunqiang Fan; Shunguang Wan; Chunyang Geng

    2012-01-01

    Research on material removal mechanism is meaningful for precision and ultra-precision manufacturing. In this paper, a novel scratch device was proposed by integrating the parasitic motion principle linear actuator. The device has a compact structure and it can be installed on the stage of the scanning electron microscope (SEM) to carry out in situ scratch testing. Effect of residual chips on the material removal process of the bulk metallic glass (BMG) was studied by in situ scratch testing ...

  19. Nanostructured Ti-Zr-Pd-Si-(Nb) bulk metallic composites: Novel biocompatible materials with superior mechanical strength and elastic recovery.

    Science.gov (United States)

    Hynowska, A; Blanquer, A; Pellicer, E; Fornell, J; Suriñach, S; Baró, M D; Gebert, A; Calin, M; Eckert, J; Nogués, C; Ibáñez, E; Barrios, L; Sort, J

    2015-11-01

    The microstructure, mechanical behaviour, and biocompatibility (cell culture, morphology, and cell adhesion) of nanostructured Ti45 Zr15 Pd35- x Si5 Nbx with x = 0, 5 (at. %) alloys, synthesized by arc melting and subsequent Cu mould suction casting, in the form of rods with 3 mm in diameter, are investigated. Both Ti-Zr-Pd-Si-(Nb) materials show a multi-phase (composite-like) microstructure. The main phase is cubic β-Ti phase (Im3m) but hexagonal α-Ti (P63/mmc), cubic TiPd (Pm3m), cubic PdZr (Fm3m), and hexagonal (Ti, Zr)5 Si3 (P63/mmc) phases are also present. Nanoindentation experiments show that the Ti45 Zr15 Pd30 Si5 Nb5 sample exhibits lower Young's modulus than Ti45 Zr15 Pd35 Si5 . Conversely, Ti45 Zr15 Pd35 Si5 is mechanically harder. Actually, both alloys exhibit larger values of hardness when compared with commercial Ti-40Nb, (HTi-Zr-Pd-Si ≈ 14 GPa, HTi-Zr-Pd-Si-Nb ≈ 10 GPa and HTi-40Nb ≈ 2.7 GPa). Concerning the biological behaviour, preliminary results of cell viability performed on several Ti-Zr-Pd-Si-(Nb) discs indicate that the number of live cells is superior to 94% in both cases. The studied Ti-Zr-Pd-Si-(Nb) bulk metallic system is thus interesting for biomedical applications because of the outstanding mechanical properties (relatively low Young's modulus combined with large hardness), together with the excellent biocompatibility. PMID:25533018

  20. Pillar Initiated Growth of High Indium Content Bulk Indium Gallium Nitride to Improve the Material Quality for Photonic Devices

    Science.gov (United States)

    McFelea, Heather Dale

    The goal of this research was to reduce dislocations and strain in high indium content bulk InGaN to improve quality for optical devices. In an attempt to achieve this goal, InGaN pillars were grown with compositions that matched the composition of the bulk InGaN grown on top. Pillar height and density were optimized to facilitate coalescence on top of the pillars. It was expected that dislocations within the pillars would bend to side facets, thereby reducing the dislocation density in the bulk overgrowth, however this was not observed. It was also expected that pillars would be completely relaxed at the interface with the substrate. It was shown that pillars are mostly relaxed, but not completely. Mechanisms are proposed to explain why threading dislocations did not bend and how complete relaxation may have been achieved by mechanisms outside of interfacial misfit dislocation formation. Phase separation was not observed by TEM but may be related to the limitations of the sample or measurements. High indium observed at facets and stacking faults could be related to the extra photoluminescence peaks measured. This research focused on the InGaN pillars and first stages of coalescence on top of the pillars, saving bulk growth and device optimization for future research.

  1. Collection of Ni-bearing material from electroless plating waste by magnetic separation with HTS bulk magnet

    Energy Technology Data Exchange (ETDEWEB)

    Oka, T., E-mail: okat@eng.niigata-u.ac.jp [Niigata University, 8050 Ikarashi-Ninocho, Nishi-ku, Niigata 950-2181 (Japan); Fukazawa, H.; Fukui, S.; Ogawa, J.; Sato, T.; Ooizumi, M. [Niigata University, 8050 Ikarashi-Ninocho, Nishi-ku, Niigata 950-2181 (Japan); Tsujimura, M. [Aichi Giken Co., 50-1 Takeshita, Hitotugi-cho, Kariya, Aichi 448-0003 (Japan); Yokoyama, K. [Ashikaga Institute of Technology, 268-1 Ohmae-cho, Ashikaga, Tochigi 326-8558 (Japan)

    2014-01-15

    Highlights: ► The magnetic separation for Ni compounds was conducted by HTS bulk magnet. ► The coarse Ni-sulfate crystals were formed from the Ni-phosphite precipitates. ► Ni-sulfate crystals was separated from the mixture of Ni-sulfate and Ni-phosphite compounds. -- Abstract: The magnetic separation experiment to collect the Ni compounds from the waste liquid of electroless plating processes was conducted in the open-gradient magnetic separation process with the high temperature superconducting bulk magnet system. The magnetic pole containing Gd-based bulk superconductors was activated to 3.45 T at 35 K in the static magnetic field of 5 T with use of a superconducting solenoid magnet. The coarse Ni-sulfate crystals were formed by adding the concentrated sulfuric acid to the Ni-phosphite precipitates which yielded from the plating waste liquid by controlling the temperature and the pH value. The open-gradient magnetic separation technique was employed to separate the Ni-sulfate crystals from the mixture of the Ni-sulfate and Ni-phosphite compounds by the difference between their magnetic properties. And we succeeded in collecting Ni-sulfate crystals preferentially to the Ni-phosphite by attracting them to the magnetic pole soon after the Ni-sulfate crystals began to grow.

  2. ZnS and ZnSe immersion gratings for astronomical high-resolution spectroscopy - evaluation of internal attenuation of bulk materials in the short NIR region

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, Y; Kobayashi, N; Kondo, S; Yasui, C; Kuzmenko, P J; Tokoro, H; Terada, H

    2009-08-12

    We measure the internal attenuation of bulk crystals of CVD-ZnS, CVD-ZnSe, Si, and GaAs, in the short near-infrared (sNIR) region to evaluate the possibility of astronomical immersion gratings with those high refractive index materials. We confirm that multispectral grade CVD-ZnS and CVD-ZnSe are best suited for the immersion gratings, with the smallest internal attenuation of {alpha}{sub att} = 0.01-0.03 cm{sup -1} among the major candidates. The measured attenuation is roughly in proportion to {lambda}{sup -2}, suggesting it is dominated by bulk scattering due to the polycrystalline grains rather than by absorption. The total transmittance in the immersion grating is estimated to be at least > 80 %, even for the spectral resolution of R = 300,000. Two potential problems, the scattered light by the bulk material and the degradation of the spectral resolution due to the gradient illumination in the diffracted beam, are investigated and found to be negligible for usual astronomical applications. Since the remaining problem, the difficulty of cutting grooves on CVD-ZnS and CVD-ZnSe, has recently been overcome by the nanoprecision fly-cutting technique, ZnS and ZnSe immersion gratings for astronomy can be technically realized.

  3. Processing of Bulk YBa2Cu3O(7-x) High Temperature Superconductor Materials for Gravity Modification Experiments and Performance Under AC Levitation

    Science.gov (United States)

    Koczor, Ronald; Noever, David; Hiser, Robert

    1999-01-01

    We have previously reported results using a high precision gravimeter to probe local gravity changes in the neighborhood of bulk-processed high temperature superconductor disks. Others have indicated that large annular disks (on the order of 25cm diameter) and AC levitation fields play an essential role in their observed experiments. We report experiments in processing such large bulk superconductors. Successful results depend on material mechanical characteristics, and pressure and heat treat protocols. Annular disks having rough dimensions of 30cm O.D., 7cm I.D. and 1 cm thickness have been routinely fabricated and tested under AC levitation fields ranging from 45 to 300OHz. Implications for space transportation initiatives and power storage flywheel technology will be discussed.

  4. Matrix effects in compositional analysis of bulk materials by PGNAA (prompt gamma/neutron activation analysis). Final report

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, V.C.; Sandquist, G.M.; Merrell, G.B.; Gozani, T.

    1984-08-01

    This feasibility study has identified and evaluated the influence of important matrix effects which arise in the commercial application of prompt gamma/neutron activation analysis (PGNAA) methods to bulk-coal analysis as follows: neutron moderation and absorption changes; gamma-ray attenuation in the sample; sample density and volume changes. The neutron-induced capture gamma spectra were found to vary in a similar, predictable manner for all neutron absorbers found in coal such as hydrogen, boron, nitrogen, chlorine, and sulfur. Three different models have been proposed from this study to analyze coal by PGNAA methods and account for the significant matrix effects arising from hydrogen variation and other system perturbations.

  5. Matrix effects in compositional analysis of bulk materials by PGNAA (prompt gamma/neutron activation analysis). Final report

    International Nuclear Information System (INIS)

    This feasibility study has identified and evaluated the influence of important matrix effects which arise in the commercial application of prompt gamma/neutron activation analysis (PGNAA) methods to bulk-coal analysis as follows: neutron moderation and absorption changes; gamma-ray attenuation in the sample; sample density and volume changes. The neutron-induced capture gamma spectra were found to vary in a similar, predictable manner for all neutron absorbers found in coal such as hydrogen, boron, nitrogen, chlorine, and sulfur. Three different models have been proposed from this study to analyze coal by PGNAA methods and account for the significant matrix effects arising from hydrogen variation and other system perturbations

  6. Material and device properties of ZnO-based film bulk acoustic resonator for mass sensing applications

    International Nuclear Information System (INIS)

    Zinc oxide based film bulk acoustic resonator as mass sensor was fabricated by multi-target magnetron sputtering under optimized deposition condition. Each layer of the device was well crystallized and highly textural observed by transmission electron microscopy and X-ray diffraction measurement. Through piezoelectric test, the device vibrated with significant distance. The influence of top electrode on resonant frequency and the bio-specimen of mass loading effect were investigated. Data show that the device has qualified properties as mass biosensor, with a resonant frequency of 3-4 GHz and a high sensitivity of 8-10 kHz cm2/ng

  7. Effect of heat cycling on microstructure and thermal property of boron carbide sintered bulk as a shielding material for fusion blanket

    International Nuclear Information System (INIS)

    In the Force Free Helical Reactor (FFHR) design activity in NIFS, metallic carbides and hydrides are considered as candidate shielding materials for the fusion blankets. These materials are expected to have some advantages on neutronic and thermo-physical properties. In order to promote the blanket design, it is necessary to clarify thermal properties of the candidate materials. We studied microstructure and thermal property of boron carbide (B4C), which is one of the promising candidates shielding materials, including the effect of heat cycling. By the laser-flash method, thermal diffusivity, which is one of the properties necessary for evaluating thermal conductivity, was measured precisely for B4C samples. The thermal diffusivity of B4C around 200degC decreased to 1/3 (5 × 10-6 m2 S-1) compared with that at room temperature. The sintering density of B4C bulk was decreased slightly by the thermal cycling. It was suggested that the B4C bulk has high thermal stability and soundness of microstructure during the life-time of blanket system. (author)

  8. Radiation hardness of silicon detectors manufactured on epitaxial material and FZ bulk enriched with oxygen, carbon, tin and platinum

    CERN Document Server

    Ruzin, A; Glaser, M; Lemeilleur, F; Talamonti, R; Watts, S; Zanet, A

    1999-01-01

    Recent results on the radiation hardness of silicon detectors fabricated on epitaxial and float zone bulk silicon enriched by various impurities, such as carbon, oxygen, tin and platinum are reported. A new methodology of measurements of electrical properties of the devices has been utilized in the experiment. It has been shown that in the case of irradiation by protons, oxygen enriched silicon has better radiation hardness than standard float zone silicon. The carbon enriched silicon detectors, on the other hand, exhibited significantly inferior radiation hardness compared to standard detectors. This study shows for the first time, a violation of the widely used normalization technique of the various particle irradiations by NIEL coefficients. The study has been carried out in the framework of the RD48 (ROSE) collaboration, which studies the radiation hardening of silicon detectors. (5 refs).

  9. Radiation hardness of silicon detectors manufactured on epitaxial material and FZ bulk enriched with oxygen, carbon, tin and platinum

    International Nuclear Information System (INIS)

    Recent results on the radiation hardness of silicon detectors fabricated on epitaxial and float zone bulk silicon enriched by various impurities, such as carbon, oxygen, tin and platinum are reported. A new methodology of measurements of electrical properties of the devices has been utilized in the experiment. It has been shown that in the case of irradiation by protons, oxygen enriched silicon has better radiation hardness than standard float zone silicon. The carbon enriched silicon detectors, on the other hand, exhibited significantly inferior radiation hardness compared to standard detectors. This study shows for the first time, a violation of the widely used normalization technique of the various particle irradiations by NIEL coefficients. The study has been carried out in the framework of the RD48 (ROSE) collaboration, which studies the radiation hardening of silicon detectors

  10. Selective observation of photo-induced electric fields inside different material components in bulk-heterojunction organic solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiangyu; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa, E-mail: iwamoto@pe.titech.ac.jp [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1, S3-33 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

    2014-01-06

    By using electric-field-induced optical second-harmonic generation (EFISHG) measurement at two laser wavelengths of 1000 nm and 860 nm, we investigated carrier behavior inside the pentacene and C{sub 60} component of co-deposited pentacene:C{sub 60} bulk-heterojunctions (BHJs) organic solar cells (OSCs). The EFISHG experiments verified the presence of two carrier paths for electrons and holes in BHJs OSCs. That is, two kinds of electric fields pointing in opposite directions are identified as a result of the selectively probing of SHG activation from C{sub 60} and pentacene. Also, under open-circuit conditions, the transient process of the establishment of open-circuit voltage inside the co-deposited layer has been directly probed, in terms of photovoltaic effect. The EFISHG provides an additional promising method to study carrier path of electrons and holes as well as dissociation of excitons in BHJ OSCs.

  11. Ti doping on the flux pinning and chemical stability against water of MgB2 bulk material

    International Nuclear Information System (INIS)

    Ti-doped MgB2 superconductors with different doping levels were prepared by solid-state reaction at ambient pressure. Jc of the samples changes with the doping level, with the best result achieved at x=0.1. At 5 K, the Jc reaches 2x106 A/cm2 in the self-field. In addition, degradation in water of Jc and irreversibility field (Hirr) of MgB2 bulks is significantly reduced by Ti doping. Microstructural analysis reveals that Ti mainly forms a thin TiB2 layer in the grain boundaries of MgB2. At the same time MgB2 grains are greatly refined, forming a strongly coupled nanoparticle structure. Our results show that the unique microstructure of the MgB2 nanoparticles with TiB2 nanograin boundaries may take the responsibility for the enhancement of the flux pinning and the chemical stability against water

  12. Nanoscale cracks at deformation twins stopped by grain boundaries in bulk and thin-film materials with nanocrystalline and ultrafine-grained structures

    International Nuclear Information System (INIS)

    Nanoscale fracture processes initiated at intersections of deformation twins and grain boundaries (GBs) in nanocrystalline and ultrafine-grained materials are theoretically described. Within the suggested description scheme, nanocracks are formed at GBs at which deformation twins are stopped and thereby produce specific GB defect configurations that create high local stresses initiating nanocracks. The conditions for realization of this new fracture mode in nanocrystalline and ultrafine-grained materials with face-centred cubic and body-centred cubic crystal lattices are calculated. The free-surface effect on crack generation at deformation twins stopped by GBs in thin-film nanocrystalline specimens is theoretically described. The critical parameters for crack generation in nanocrystalline and ultrafine-grained bulk materials and thin films are revealed. It is shown that in bulk nanomaterials nanocracks are generated at twin thicknesses of several nanometres and grow very fast with increasing twin thickness. At the same time, in thin-film nanomaterials, the equilibrium nanocrack lengths significantly decrease if the distance between the twin lamella and the closest film surface does not exceed several twin thicknesses. (paper)

  13. Micro and Macro-scale Thermo-mechanical Modelling of Bulk Deformation in Early-age Cement-based Materials

    Czech Academy of Sciences Publication Activity Database

    Kozák, Vladislav

    2011-01-01

    Roč. 465, - (2011), s. 111-114. ISSN 1013-9826. [MSMF6-Materials structure &Micromechanics of fracture. Brno, 28.06.2010-30.06.2010] R&D Projects: GA ČR GA101/08/1304 Institutional research plan: CEZ:AV0Z20410507 Keywords : cemen-based composites * scale bridging Subject RIV: JI - Composite Materials

  14. Large difference between the magnetic properties of Ba and Ti co-doped BiFeO$_3$ bulk materials and their corresponding nanoparticles prepared by ultrasonication

    OpenAIRE

    Ahmmad, Bashir; Kanomata, Kensaku; Koike, Kunihiro; Kubota, Shigeru; Kato, Hiroaki; Hirose, Fumihiko; Billah, Areef; Jalil, M. A.; Basith, M. A.

    2016-01-01

    The ceramic pellets of the nominal compositions Bi$_{0.7}$Ba$_{0.3}$Fe$_{1-x}$Ti$_x$O$_3$ (x = 0.00-0.20) were prepared initially by standard solid state reaction technique. The pellets were then ground into micrometer-sized powders and mixed with isopropanol in an ultrasonic bath to prepare nanoparticles. The X-ray diffraction patterns demonstrate the presence of a significant number of impurity phases in bulk powder materials. Interestingly, these secondary phases were completely removed du...

  15. Low-Thermal-Conductivity (MS)1+x(TiS2)2 (M = Pb, Bi, Sn) Misfit Layer Compounds for Bulk Thermoelectric Materials

    OpenAIRE

    Chunlei Wan; Yifeng Wang; Ning Wang; Kunihito Koumoto

    2010-01-01

    A series of (MS)1+x(TiS2)2 (M = Pb, Bi, Sn) misfit layer compounds are proposed as bulk thermoelectric materials. They are composed of alternating rock-salt-type MS layers and paired trigonal anti-prismatic TiS2 layers with a van der Waals gap. This naturally modulated structure shows low lattice thermal conductivity close to or even lower than the predicted minimum thermal conductivity. Measurement of sound velocities shows that the ultra-low thermal conductivity partially originates from th...

  16. Quantifying bulk electrode strain and material displacement within lithium batteries via high-speed operando tomography and digital volume correlation

    OpenAIRE

    Finegan, D. P.; Tudisco, E.; Scheel, M; Robinson, J B; Taiwo, O. O.; Eastwood, D. S.; Lee, P. D.; Di Michiel, M.; Bay, B.; Hall, S. A.; Hinds, G.; Brett, D. J. L.; Shearing, P. R.

    2015-01-01

    Tracking the dynamic morphology of active materials during operation of lithium batteries is essential for identifying causes of performance loss. Digital volume correlation (DVC) is applied to high-speed operando synchrotron X-ray computed tomography of a commercial Li/MnO2 primary battery during discharge. Real-time electrode material displacement is captured in 3D allowing degradation mechanisms such as delamination of the electrode from the current collector and electrode crack formation ...

  17. Micro and Macro-scale Thermo-mechanical Modelling of Bulk Deformation in Early-age Cement-based Materials

    Czech Academy of Sciences Publication Activity Database

    Kozák, Vladislav

    Brno : VUTIUM Brno, 2010 - (Šandera, P.). s. 53-53 ISBN 978-80-214-4112-5. [MSMF6-Materials structure &Micromechanics of fracture. 28.06.2010-30.06.2010, Brno] R&D Projects: GA ČR GA101/08/1304 Institutional research plan: CEZ:AV0Z20410507 Keywords : cemen-based composites * scale bridging * FEM Subject RIV: JI - Composite Materials

  18. Effect of residual chips on the material removal process of the bulk metallic glass studied by in situ scratch testing inside the scanning electron microscope

    Directory of Open Access Journals (Sweden)

    Hu Huang

    2012-12-01

    Full Text Available Research on material removal mechanism is meaningful for precision and ultra-precision manufacturing. In this paper, a novel scratch device was proposed by integrating the parasitic motion principle linear actuator. The device has a compact structure and it can be installed on the stage of the scanning electron microscope (SEM to carry out in situ scratch testing. Effect of residual chips on the material removal process of the bulk metallic glass (BMG was studied by in situ scratch testing inside the SEM. The whole removal process of the BMG during the scratch was captured in real time. Formation and growth of lamellar chips on the rake face of the Cube-Corner indenter were observed dynamically. Experimental results indicate that when lots of chips are accumulated on the rake face of the indenter and obstruct forward flow of materials, materials will flow laterally and downward to find new location and direction for formation of new chips. Due to similar material removal processes, in situ scratch testing is potential to be a powerful research tool for studying material removal mechanism of single point diamond turning, single grit grinding, mechanical polishing and grating fabrication.

  19. Effect of residual chips on the material removal process of the bulk metallic glass studied by in situ scratch testing inside the scanning electron microscope

    International Nuclear Information System (INIS)

    Research on material removal mechanism is meaningful for precision and ultra-precision manufacturing. In this paper, a novel scratch device was proposed by integrating the parasitic motion principle linear actuator. The device has a compact structure and it can be installed on the stage of the scanning electron microscope (SEM) to carry out in situ scratch testing. Effect of residual chips on the material removal process of the bulk metallic glass (BMG) was studied by in situ scratch testing inside the SEM. The whole removal process of the BMG during the scratch was captured in real time. Formation and growth of lamellar chips on the rake face of the Cube-Corner indenter were observed dynamically. Experimental results indicate that when lots of chips are accumulated on the rake face of the indenter and obstruct forward flow of materials, materials will flow laterally and downward to find new location and direction for formation of new chips. Due to similar material removal processes, in situ scratch testing is potential to be a powerful research tool for studying material removal mechanism of single point diamond turning, single grit grinding, mechanical polishing and grating fabrication.

  20. The influence of microstructure on charge separation dynamics in organic bulk heterojunction materials for solar cell applications

    KAUST Repository

    Scarongella, Mariateresa

    2014-01-01

    Light-induced charge formation is essential for the generation of photocurrent in organic solar cells. In order to gain a better understanding of this complex process, we have investigated the femtosecond dynamics of charge separation upon selective excitation of either the fullerene or the polymer in different bulk heterojunction blends with well-characterized microstructure. Blends of the pBTTT and PBDTTPD polymers with PCBM gave us access to three different scenarios: either a single intermixed phase, an intermixed phase with additional pure PCBM clusters, or a three-phase microstructure of pure polymer aggregates, pure fullerene clusters and intermixed regions. We found that ultrafast charge separation (by electron or hole transfer) occurs predominantly in intermixed regions, while charges are generated more slowly from excitons in pure domains that require diffusion to a charge generation site. The pure domains are helpful to prevent geminate charge recombination, but they must be sufficiently small not to become exciton traps. By varying the polymer packing, backbone planarity and chain length, we have shown that exciton diffusion out of small polymer aggregates in the highly efficient PBDTTPD:PCBM blend occurs within the same chain and is helped by delocalization. This journal is © the Partner Organisations 2014.

  1. Optimization of a solar-blind and middle infrared two-colour photodetector using GaN-based bulk material and quantum wells

    International Nuclear Information System (INIS)

    This paper calculates the wavelengths of the interband transitions as a function of the Al mole fraction of A1xGa1–xN bulk material. It is finds that when the Al mole fraction is between 0.456 and 0.639, the wavelengths correspond to the solar-blind (250 nm to 280 nm). The influence of the structure parameters of A1yGa1–yN/GaN quantum wells on the wavelength and absorption coefficient of intersubband transitions has been investigated by solving the Schrödinger and Poisson equations self-consistently. The A1 mole fraction of the A1yGa1–yN barrier changes from 0.30 to 0.46, meanwhile the width of the well changes from 2.9 nm to 2.2 nm, for maximal intersubband absorption in the window of the air (3 μm < λ < 5 μm). The absorption coefficient of the intersubband transition between the ground state and the first excited state decreases with the increase of the wavelength. The results are finally used to discuss the prospects of GaN-based bulk material and quantum wells for a solar-blind and middle infrared two-colour photodetector. (classical areas of phenomenology)

  2. Bulk undercooling

    Science.gov (United States)

    Kattamis, T. Z.

    1984-01-01

    Bulk undercooling methods and procedures will first be reviewed. Measurement of various parameters which are necessary to understand the solidification mechanism during and after recalescence will be discussed. During recalescence of levitated, glass-encased large droplets (5 to 8 mm diam) high speed temperature sensing devices coupled with a rapid response oscilloscope are now being used at MIT to measure local thermal behavior in hypoeutectic and eutectic binary Ni-Sn alloys. Dendrite tip velocities were measured by various investigators using thermal sensors or high speed cinematography. The confirmation of the validity of solidification models of bulk-undercooled melts is made difficult by the fineness of the final microstructure, the ultra-rapid evolution of the solidifying system which makes measurements very awkward, and the continuous modification of the microstructure which formed during recalescence because of precipitation, remelting and rapid coarsening.

  3. Multi-scale defect engineering and interface modification for enhancement of thermoelectric properties in nanostructured bulk materials

    Science.gov (United States)

    Puneet, Pooja

    Firstly, the effects of extrinsic point defects, such as rattlers (Ce, In, Ba, Yb), dopants (Co, Ni) and secondary phases on FeSb 3 and CoSb3 based p-type skutterudites on the transport and magnetic properties is studied. 'Phonon glass and electron crystal' like behavior was observed in Ni-doped skutterudites. Interestingly, we found that the addition of In facilitated the formation of secondary phases with various morphologies upon surpassing the filling fraction limits. Such in-situ secondary phases were in fact found to be beneficial to the system altering their electrical transport properties, and thereby increasing the ZT of the system as compared to that of the parent compound. The highest ZT value of 0.9 at 650 K was reported for p-type skutterudite sample with nominal composition In0.1Ce0.9Fe3.5 Ni0.5Sb12. In the low temperature regime (T behavior. The crystal field effects due to the splitting of ground state of Ce (4f level) in presence of cubic crystalline field were observed to dictate the magnetic properties below 100 K. Further, our magnetic susceptibility data is consistent with a crystal field splitting gap of ˜39 meV (˜450 K). The intrinsic surface or interfacial defects in elemental Bismuth were introduced by controlling the surface-to-volume ratio using a combination of high energy ballmilling and spark plasma sintering (SPS) processes. The obtained ball-milled powders were SPS processed with different ON-OFF time ratios of the DC current pulses to further modify the nature and extent of these surfaces. The 'double decoupling' (simultaneous optimization of the thermopower, electrical conductivity and thermal conductivity) in single element polycrystalline Bi was observed via a combination of an increase in the surface-to-volume ratio achieved by ball milling process and an interface (or grain boundary) modification by the SPS process. As a result, a greater than six-fold improvement in the PF, and hence ZT, was achieved in polycrystalline bulk

  4. Overview of Workshop on Evaluation of Simulation Techniques for Radiation Damage in the Bulk of Fusion First Wall Materials

    DEFF Research Database (Denmark)

    Leffers, Torben; Singh, Bachu Narain; Green, W.V.;

    1984-01-01

    The main points and the main conclusions of a workshop held June 27–30 1983 at Interlaken, Switzerland, are reported. There was general agreement among the participants that ideal simulation, providing unambiguous information about the behaviour of the first wall material, is at present out of...

  5. Simple and quick enhancement of SiC bulk crystal growth using a newly developed crucible material

    Science.gov (United States)

    Nakamura, Daisuke

    2016-05-01

    Newly developed highly reliable low-cost TaC-coated graphite materials prepared by a wet ceramic process were applied to SiC sublimation growth. We demonstrated an increased long-duration growth rate and a resultant increase in crystal size by a factor of ∼1.2 (experimental value) after 24 h of growth [and ∼1.5 (extrapolated value) after the optimum duration of 53.1 h] by simply and quickly replacing graphite crucibles with TaC-coated graphite crucibles. Growth with the TaC-coated graphite crucibles reduced source gas leakage and increased the material yield for single crystals because the TaC layers were gas-tight and had a low emissivity.

  6. Influence of Cu content on the n → p transition of 15% Sn-doped Cu{sub x}(In,Ga)Se{sub 2} bulk materials

    Energy Technology Data Exchange (ETDEWEB)

    Monsefi, Mehrdad; Kuo, Dong-Hau, E-mail: dhkuo@mail.ntust.edu.tw

    2013-12-15

    Highlights: •We studied the donor Sn-doped Cu(In,Ga)Se{sub 2} or CIGSe bulks at different Cu contents. •Cu-less CIGSe is used to control carrier concentration but easily loss mobility. •Sn doping here is to control the carrier concentration but keep high Cu content. •By changing the Cu content, n- and p-type CIGSe with good properties were achieved. •The CIGSe absorber shows the property diversity with the donor doping. -- Abstract: The elaborated Sn-doped Cu(In,Ga)Se{sub 2} (Sn-CIGSe) bulk materials with different Cu ratios had been sintered at 650 °C. Sn-CIGSe was reactively sintered with Sb{sub 2}S{sub 3} and Te sintering aids. Electrical properties of Sn-CIGSe were measured and the variations in mobility, charge carrier density, and conductivity were rationalized. The Sn{sup 4+} donor in Cu-poor CIGSe favored the n-type behavior and the Cu deficiency increased electron concentration due to the formation of the indium-to-copper donor. The n → p transition for the Cu-rich Sn-CIGSe is related to the partial formation of the copper-to-indium and Sn{sup 2+} acceptor. Carrier mobility above 12 cm{sup 2}/V s can be achieved for Sn-CIGSe with a higher Cu content. The advantages of Sn doping in CIGSe were claimed.

  7. Polymerisationseigenschaften von Bulk-Fill Kompositen

    OpenAIRE

    Maier, Eva

    2015-01-01

    Hintergrund und Ziele: Untersuchung der Polymerisationseigenschaften von Bulk-Fill Kompositen bzgl. Konversionsrate (degree of conversion = DC), Vickers-Härte (HV), Polymerisationsschrumpfungsstress (PSS) und Polymerisationsvolumenschrumpfung (PVS) im Vergleich zu konventionellen Kompositen. Material und Methode: Untersucht wurden die Bulk-Fill Komposite Filtek Bulk Fill Flowable (FBF, 3M ESPE, Seefeld), Surefil Smart Dentin Replacement (SDR, Dentsply, Konstanz), Tetric EvoCeram Bulk Fill...

  8. Bulk-Fill Resin Composites

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Havndrup-Pedersen, Cæcilie; Honoré, Daniel;

    2015-01-01

    restorative procedure. The aim of this study, therefore, was to compare the depth of cure, polymerization contraction, and gap formation in bulk-fill resin composites with those of a conventional resin composite. To achieve this, the depth of cure was assessed in accordance with the International Organization...... for Standardization 4049 standard, and the polymerization contraction was determined using the bonded-disc method. The gap formation was measured at the dentin margin of Class II cavities. Five bulk-fill resin composites were investigated: two high-viscosity (Tetric EvoCeram Bulk Fill, SonicFill) and...... three low-viscosity (x-tra base, Venus Bulk Fill, SDR) materials. Compared with the conventional resin composite, the high-viscosity bulk-fill materials exhibited only a small increase (but significant for Tetric EvoCeram Bulk Fill) in depth of cure and polymerization contraction, whereas the low...

  9. Creating bulk nanocrystalline metal.

    Energy Technology Data Exchange (ETDEWEB)

    Fredenburg, D. Anthony (Georgia Institute of Technology, Atlanta, GA); Saldana, Christopher J. (Purdue University, West Lafayette, IN); Gill, David D.; Hall, Aaron Christopher; Roemer, Timothy John (Ktech Corporation, Albuquerque, NM); Vogler, Tracy John; Yang, Pin

    2008-10-01

    Nanocrystalline and nanostructured materials offer unique microstructure-dependent properties that are superior to coarse-grained materials. These materials have been shown to have very high hardness, strength, and wear resistance. However, most current methods of producing nanostructured materials in weapons-relevant materials create powdered metal that must be consolidated into bulk form to be useful. Conventional consolidation methods are not appropriate due to the need to maintain the nanocrystalline structure. This research investigated new ways of creating nanocrystalline material, new methods of consolidating nanocrystalline material, and an analysis of these different methods of creation and consolidation to evaluate their applicability to mesoscale weapons applications where part features are often under 100 {micro}m wide and the material's microstructure must be very small to give homogeneous properties across the feature.

  10. Enhanced glass-forming ability of FeCoBSiNb bulk glassy alloys prepared using commercial raw materials through the optimization of Nb content

    International Nuclear Information System (INIS)

    We optimized the alloy compositions by modifying the Nb content in [(Fe0.5Co0.5)0.75B0.20Si0.05]100-xNbx(x=3.6-4.4) alloy system. As a result, it was found that the Nb content of 4.3 at. % was effective for approaching alloy to a eutectic point. By copper mold casting, [(Fe0.5Co0.5)0.75B0.20Si0.05]95.7Nb4.3 bulk glassy alloy rods with diameters up to 4 mm were successfully synthesized even using commercial raw materials. These glassy alloys exhibit a rather high saturation magnetization of 0.77 T and low coercive force of 2.5 A/m.

  11. Feasibility study of prompt gamma neutron activation analysis (PGNAA) of explosives simulants and bulk material using DD/DT neutron generator

    Science.gov (United States)

    Bishnoi, S.; Sarkar, P. S.; Patel, T.; Adhikari, P. S.; Sinha, Amar

    2013-04-01

    Elemental characterization of low Z elements (C,H,Cl,Fe) inside bulk materials were performed using PGNAA technique. Samples having elemental composition similar to explosives were used for such experimentations using moderated DD neutrons as well as DT(14MeV) neutrons. We could observe characteristic prompt capture gamma rays of hydrogen (2.224MeV), nitrogen (10.83 MeV), chlorine (6.11 MeV) and Fe (6.02MeV and 7.63MeV) also (n,n'γ) prompt gamma signal (4.43MeV) of carbon. BGO detector has been used for gamma spectrum acquisition. These experimentations has been carried out for initial feasibility studies of detecting prompt gamma lines as a part of PGNAA technique based explosive detection system development. A detail description of experimental set up and procedure has been discussed in paper.

  12. Effect of the Side Chains and Anode Material on Thermal Stability and Performance of Bulk-Heterojunction Solar Cells Using DPP(TBFu2 Derivatives as Donor Materials

    Directory of Open Access Journals (Sweden)

    Alexander Kovalenko

    2015-01-01

    Full Text Available An optimized fabrication of bulk-heterojunction solar cells (BHJ SCs based on previously reported diketopyrrolopyrrole donor, ethyl-hexylated DPP(TBFu2, as well as two new DPP(TBFu2 derivatives with ethyl-hexyl acetate and diethyl acetal solubilizing side-chains and PC60BM as an acceptor is demonstrated. Slow gradual annealing of the solar cell causing the effective donor-acceptor reorganization, and as a result higher power conversion efficiency (PCE, is described. By replacing a hole transporting layer PEDOT:PSS with MoO3 we obtained higher PCE values as well as higher thermal stability of the anode contact interface. DPP(TBFu2 derivative containing ethyl-hexyl acetate solubilizing side-chains possessed the best as-cast self-assembly and high crystallinity. However, the presence of ethyl-hexyl acetate and diethyl acetal electrophilic side-chains stabilizes HOMO energy of isolated DPP(TBFu2 donors with respect to the ethyl-hexylated one, according to cyclic voltammetry.

  13. Atomistic simulations of thermal transport in Si and SiGe based materials: From bulk to nanostructures

    Science.gov (United States)

    Savic, Ivana; Mingo, Natalio; Donadio, Davide; Galli, Giulia

    2010-03-01

    It has been recently proposed that Si and SiGe based nanostructured materials may exhibit low thermal conductivity and overall promising properties for thermoelectric applications. Hence there is a considerable interest in developing accurate theoretical and computational methods which can help interpret recent measurements, identify the physical origin of the reduced thermal conductivity, as well as shed light on the interplay between disorder and nanostructuring in determining a high figure of merit. In this work, we investigate the capability of an atomistic Green's function method [1] to describe phonon transport in several types of Si and SiGe based systems: amorphous Si, SiGe alloys, planar and nanodot Si/SiGe multilayers. We compare our results with experimental data [2,3], and with the findings of molecular dynamics simulations and calculations based on the Boltzmann transport equation. [1] I. Savic, N. Mingo, and D. A. Stewart, Phys. Rev. Lett. 101, 165502 (2008). [2] S.-M. Lee, D. G. Cahill, and R. Venkatasubramanian, Appl. Phys. Lett. 70, 2957 (1997). [3] G. Pernot et al., submitted.

  14. Initial experience in the underground use of laser scanners in the monitoring of bulk materials; Erste Erfahrungen beim untertaegigen Einsatz von Laserscannern in der Massengutueberwachung

    Energy Technology Data Exchange (ETDEWEB)

    Voss, H.W. [RAG Aktiengesellschaft, Bottrop (Germany). Bergwerk Prosper-Haniel

    2008-04-17

    The profitability of coal mines is significantly affected by the structural and organisational conditions in the area of bulk material transport. The introduction and implementation of measures to improve logistics constitutes a permanent challenge in the mines. The continuous increase in face outputs in the mines of RAG by the use of increasingly efficient coal-winning equipment also imposes higher demands on the conveyor belts. The capacity of the infrastructure is not high enough in many cases to cope with these quantities. In addition to organisational solutions investigation of the conveyor system to determine optimum or maximum utilisation of capacity is necessary. This has been done at the Prosper-Haniel mine with offline and online simulation systems for several years. The contribution includes further development of mass flow measurement, the newly used volumetric flow measuring system and thus the possibility of direct determination of the dirt content in the material conveyed from the workings. In conjunction with the face data direct determination of the quantity of dirt cut with the coal is possible. (orig.)

  15. Bulk materials handling equipment roundup

    Energy Technology Data Exchange (ETDEWEB)

    Fiscor, S.

    2007-07-15

    The article reports recent product developments in belt conveyors. Flexco Steel Lancing Co. (Flexco) has a range of light, portable maintenance tools and offers training modules on procedures for belt conveyor maintenance on its website www.flexcosafe.com. Siemens recently fitted a 19 km long conveyor belt drive system at a Texan aluminium plant with five 556-kW Simovent Masterdrive VC drives. Voith recently launched the TPKL-T turbo coupling for users who want an alignment-free drive solution. Belt cleaners newly on the market include the RemaClean SGB brush and ASGCO Manufacturing's Razor-Back with Spray bar. Continental Conveyor has introduced a new line of dead-shaft pulleys offering increased bearing protection. 6 photos.

  16. Ferromagnetic bulk glassy alloys

    International Nuclear Information System (INIS)

    This paper deals with the review on the formation, thermal stability and magnetic properties of the Fe-based bulk glassy alloys in as-cast bulk and melt-spun ribbon forms. A large supercooled liquid region over 50 K before crystallization was obtained in Fe-(Al, Ga)-(P, C, B, Si), Fe-(Cr, Mo, Nb)-(Al, Ga)-(P, C, B) and (Fe, Co, Ni)-Zr-M-B (M=Ti, Hf, V, Nb, Ta, Cr, Mo and W) systems and bulk glassy alloys were produced in a thickness range below 2 mm for the Fe-(Al, Ga)-(P, C, B, Si) system and 6 mm for the Fe-Co-(Zr, Nb, Ta)-(Mo, W)-B system by copper-mold casting. The ring-shaped glassy Fe-(Al, Ga)-(P, C, B, Si) alloys exhibit much better soft magnetic properties as compared with the ring-shaped alloy made from the melt-spun ribbon because of the formation of the unique domain structure. The good combination of high glass-forming ability and good soft magnetic properties indicates the possibility of future development as a new bulk glassy magnetic material

  17. Determination of the easy axes of small ferromagnetic precipitates in a bulk material by combined magnetic force microscopy and electron backscatter diffraction techniques

    International Nuclear Information System (INIS)

    A method to determine the magnetic easy axes of micro- and nanoscopic ferromagnetic precipitates embedded in a bulk material is proposed and applied to globular cementite (Fe3C) embedded in a ferrite matrix. The method combines magnetic force microscopy (MFM) with electron backscattered diffraction (EBSD) measurements. Magnetic domain structures in globular and in lamellar cementite precipitates in unalloyed pearlitic steels were imaged using MFM. The domain structure of the precipitates was analyzed in dependency of their size, shape and crystallographic orientation. It was found that the magnetic moments of the cementite precipitates are highly geared to their crystalline axes. The combined MFM and EBSD studies allow the conclusion that the cementite easy direction of magnetization is the long [010] axis. For fine lamellae cementite the determination of their crystallographic orientations using electron diffraction techniques is very difficult. With the previous knowledge of the behavior of the domain structure in globular cementite, the crystalline orientations of the fine lamellae cementite can be estimated by simply observing the magnetic microstructures and the topographic profiles. - Highlights: • We develop a method to determine the easy axes of nanoscopic ferromagnetic precipitates in a matrix. • We combine the magnetic force microscopy and the electron backscatter diffraction techniques. • Globular and lamellar cementite (Fe3C) precipitates are taken as examples. • MFM images revealed different orientations of the magnetic moments in cementite. • The cementite easy direction of magnetization is the long [010] axis

  18. Electronic structure in the bulk and at the surface of lanthanide materials. A detailed study with X-ray emission and inverse photoemission

    CERN Document Server

    Huebinger, F

    2000-01-01

    LaTe. With measurements of the O3-XE in the Lanthanum-Chalcogenides we could demonstrate the transfer of s-like valence electrons from the Lanthanum atom to the Chalcogen atom. Furthermore, the binding energy of the state at the Lanthanum atom was determined. The surface core-level shift is smaller by 25 % in the Chalcogenides than in La-metal. We also describe a theoretical model, which qualitatively explains the observed larger shifts of the core-level binding energy in PE than in IPE from Lanthan-Chalcogenides. This dissertation is concerned with the occupied and unoccupied electronic structure of lanthanide materials. With surface sensitive electron-excited x-ray emission spectroscopy (XES) we could experimentally determine a surface and bulk partial density of states (p-DOS) for the metals Lanthanum, Lutetium and Samarium. From calculations of the O3-XE transition probability we anticipate a three times higher probability for s-like than for d-like electrons to fill the 5p3/2-hole; this was confirmed exp...

  19. On-line bulk analysis of raw material in a cement plant using the neutron irradiation and capture gamma ray technique

    International Nuclear Information System (INIS)

    In collaboration with Ciments Lafarge, the Laboratoire central des ponts et chaussees (LCPC) has developed a technique, involving neutron irradiation, for on-line bulk analysis of raw material quality, along the input line to a cement plant, by determining the quantities of the following elements: calcium, silicon, aluminium and iron. A system was constructed and tested in a cement plant under actual service conditions. The system consists of a sampler placed on the on-stream line supplying the plant at a rate of 1000 t/h. An analysing hopper incorporating a neutron irradiation system, consisting of a 14 MeV neutron generator tube, and a gamma ray detection system, comprising a NaI(Tl) scintillator associated with a photomultiplier, are coupled to this sampler. The system is fed continuously with the raw material to be analysed. Gamma radiation spectra supplied by the detector are analysed on two distinct measurement channels. One of these channels processes the nuclear radiation generated by neutron capture phenomena, while the other channel processes the nuclear radiation resulting from neutron activation phenomena. The data collected under the operating conditions mentioned above (i.e. in real time) allows readings to be obtained every 2 min for silicon, calcium, aluminium and iron as a result of the processing method applied to gamma capture and activation spectra. A comparison was made between these measurements and the results of an analysis of the same piles, conducted simultaneously through a sampling tower delivering at an hourly rate a sample analysed in accord with the X ray fluorescence process. Comparison of the results obtained from both analysis methods highlights the advantages of the neutron irradiation process. (author). 4 figs, 2 tabs

  20. Mechanically induced self-propagating reaction and consequent consolidation for the production of fully dense nanocrystalline Ti{sub 55}C{sub 45} bulk material

    Energy Technology Data Exchange (ETDEWEB)

    Sherif El-Eskandarany, M., E-mail: msherif@kisr.edu.kw; Al-Hazza, Abdulsalam

    2014-11-15

    We employed a high-energy ball mill for the synthesis of nanograined Ti{sub 55}C{sub 45} powders starting from elemental Ti and C powders. The mechanically induced self-propagating reaction that occurred between the reactant materials was monitored via a gas atmosphere gas-temperature-monitoring system. A single phase of NaCl-type TiC was obtained after 5 h of ball milling. To decrease the powder and grain sizes, the material was subjected to further ball milling time. The powders obtained after 200 h of milling possessed spherical-like morphology with average particle and grain sizes of 45 μm and 4.2 nm, respectively. The end-products obtained after 200 h of ball milling time, were then consolidated into full dense compacts, using hot pressing and spark plasma sintering at 1500 and 34.5 MPa, with heating rates of 20 °C/min and 500 °C/min, respectively. Whereas hot pressing of the powders led to severe grain growth (∼ 436 nm in diameter), the as-spark plasma sintered powders maintained their nanograined characteristics (∼ 28 nm in diameter). The as-synthesized and as-consolidated powders were characterized, using X-ray diffraction, high-resolution electron microscopy, and scanning electron microscopy. The mechanical properties of the consolidated samples obtained via the hot pressing and spark plasma sintering techniques were characterized, using Vickers microhardness and non-destructive testing techniques. The Vickers hardness, Young's modulus, shear modulus and fracture toughness of as-spark plasma sintered samples were 32 GPa, 358 GPa, 151 GPa and 6.4 MPa·m{sup 1/2}, respectively. The effects of the consolidation approach on the grain size and mechanical properties were investigated and are discussed. - Highlights: • Room-temperature synthesizing of NaCl-type TiC • Dependence on the grain size on the ball milling time • Fabrication of equiaxed nanocrystalline grains with a diameter of 4.2 nm • Fabrication of nanocrystalline bulk TiC material

  1. Handling of bulk solids theory and practice

    CERN Document Server

    Shamlou, P A

    1990-01-01

    Handling of Bulk Solids provides a comprehensive discussion of the field of solids flow and handling in the process industries. Presentation of the subject follows classical lines of separate discussions for each topic, so each chapter is self-contained and can be read on its own. Topics discussed include bulk solids flow and handling properties; pressure profiles in bulk solids storage vessels; the design of storage silos for reliable discharge of bulk materials; gravity flow of particulate materials from storage vessels; pneumatic transportation of bulk solids; and the hazards of solid-mater

  2. Structural, chemical, and thermoelectric properties of Bi{sub 2}Te{sub 3} Peltier materials. Bulk, thin films, and superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Peranio, Nicola

    2008-07-01

    In this work, the nature of the natural nanostructure (nns) was analysed and the correlations to the transport coefficients, particularly the lattice thermal conductivity, is discussed. Experimental methods are presented for the first time, yielding an accurate quantitative analysis of the chemical composition and of stress fields in Bi{sub 2}Te{sub 3} and in compounds with similar structural and chemical microstructures. This work can be subdivided as follows: (I) N-type Bi{sub 2}(Te{sub 0.91}Se{sub 0.09}){sub 3} and p-type (Bi{sub 0.26}Sb{sub 0.74}){sub 1.98}(Te{sub 0.99}Se{sub 0.01}){sub 3.02} bulk materials synthesised by the Bridgman technique. (II) Bi{sub 2}Te{sub 3} thin films and Bi{sub 2}Te{sub 3}/Bi{sub 2}(Te{sub 0.88}Se{sub 0.12}){sub 3} superlattices epitaxially grown by molecular beam epitaxy (MBE) on BaF{sub 2} substrates with periods of {delta}-12 nm at the Fraunhofer-Institut fuer Physikalische Messtechnik (IPM). (III) Experimental methods, i.e., TEM specimen preparation, high-accuracy quantitative chemical analysis by EDX in the TEM, and image simulations of dislocations and the nns according to the two-beam dynamical diffraction theory. The nns was analysed in detail by stereomicroscopy and by image simulation and was found to be a pure sinusoidal displacement field with (i) a displacement vector parallel to <5,-5,1> and an amplitude of about 10 pm and (ii) a wave vector parallel to {l_brace}1,0,10{r_brace} and a wavelength of 10 nm. The results obtained here showed a significant amount of stress in the samples, induced by the nns which was still not noticed and identified. Both kinds of nanostructures, artificial (ans) and natural (nns) nanostructures, yielded in thermoelectric materials a low lattice thermal conductivity which was beneficial for the thermoelectric figure of merit ZT. (orig.)

  3. Corrosion of lanthanum magnesium hexaaluminate as plasma-sprayed coating and as bulk material when exposed to molten V2O5-containing salt

    International Nuclear Information System (INIS)

    Highlights: • Corrosion behavior of LaMgAl11O19 bulk and plasma sprayed coating has been compared. • Degradation mechanism is investigated based on LaMgAl11O19’s crystal chemistry. • LaMgAl11O19 coating displays inferior corrosion resistance to well crystallized bulk. - Abstract: Corrosion of LaMgAl11O19 (LaMA) bulk and plasma sprayed coating was studied in molten V2O5-containing salt at 710–1050 °C in air. Results indicate that the well crystallized LaMA bulk exhibited prior corrosion resistance to the plasma sprayed LaMA coating with amorphous phase and reduced chemical bond strength in its crystal structure. La–O chemical bonds with the lowest bond energies were the easiest bonds in the LaMA crystal to be broken by molten V2O5-containing salt attack to form LaVO4 at each temperature level for both LaMA bulk and coating. Corrosion products of the LaMA coating were much different at temperature below 900 °C

  4. Explosive bulk charge

    Science.gov (United States)

    Miller, Jacob Lee

    2015-04-21

    An explosive bulk charge, including: a first contact surface configured to be selectively disposed substantially adjacent to a structure or material; a second end surface configured to selectively receive a detonator; and a curvilinear side surface joining the first contact surface and the second end surface. The first contact surface, the second end surface, and the curvilinear side surface form a bi-truncated hemispherical structure. The first contact surface, the second end surface, and the curvilinear side surface are formed from an explosive material. Optionally, the first contact surface and the second end surface each have a substantially circular shape. Optionally, the first contact surface and the second end surface consist of planar structures that are aligned substantially parallel or slightly tilted with respect to one another. The curvilinear side surface has one of a smooth curved geometry, an elliptical geometry, and a parabolic geometry.

  5. Preparation of novel bulk carbon nano tubes dental materials for implant%新型牙用碳纳米管种植体材料的制备

    Institute of Scientific and Technical Information of China (English)

    陈蕾; Mian Farrukh Imran; 蔡惠; 徐国富

    2008-01-01

    , Japanese MitutoyoHM-101 little burden Vickers hardness meter was used to test the apparent bulk density, specific surface area, Vickers hardness at the different contents of PCS and sintering pressures. Scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to observe the microstructure of the material.RESULTS: ① Microstructure: SEM and TEM indicated that the nanotube structure of the material was retained after sintered. ② Conforming phase of material: X-ray diffractometer indicated that carbon nanotubes were felt by PCS pyrolysis product of SiC; along with the PCS content and sintering pressure increased, the specific surface area was reduced, and Vickers hardness and density increased. Specific surface area decreased. ③ Histological compatibility: The inflammatory reactions of the CNTs/PCS were little more serious along with the increase of the content of PCS. The physical property of carbon nanotubes was prepared in this way, it was closed to bone tissues, it had the better biocompatibility, and it was the suitable candidate implant denture material.CONCLUSION: Appropriate to PCS for the bonding agent, through SPS, at 1 200 ℃, 20-60 MPa sintering pressure, CNTs/PCS which the material property is closed to bone tissues can be prepared, and CNTs/PCS subcutaneous implantation in rats does not show significant rejection; therefore, it is suitable candidate for dental implants material.%背景:碳纳米管是一种直径约1 nm,长1~10 μm的圆筒状物质,具有比石墨还小的密度;加上足够高的强度,碳纳米管有望用于骨替代材料.目的:初步考察聚碳硅烷含量和烧结压力对碳纳米管材料性能的影响,寻求大块碳纳米管材料的最适制备条件,并分析所制备的碳纳米管材料的物理性能和生物相容性,为临床候选牙用种植体材料提供选择依据.设计:实验通过调整结合剂的含量和烧结压力,确定材料的最适制备条件,

  6. High-precision Mg isotope measurements of terrestrial and extraterrestrial material by HR-MC-ICPMS - implications for the relative and absolute Mg isotope composition of the bulk silicate Earth

    DEFF Research Database (Denmark)

    Bizzarro, Martin; Paton, Chad; Larsen, Kirsten Kolbjørn;

    2011-01-01

    martian shergottite and sea water samples. Repeated analyses of terrestrial and extraterrestrial samples demonstrate that it is possible to routinely measure the relative Mg-isotope composition of silicate materials with an external reproducibility of 2.5 and 20 ppm for the m26Mg* and m25Mg values...... the Mg-isotope composition of inner solar system bulk planetary materials is uniform within the resolution of our analyses. We have determined the absolute Mg-isotope composition of the J12 olivine, two CI chondrites as well as the DSM-3 and Cambridge-1 reference standards using a mixed 26Mg-24Mg...... absolute Mg-isotope composition for Earth’s mantle – and hence that of the bulk silicate Earth – to be 25Mg/24Mg 1/4 0.126896 ¿ 0.000025 and 26Mg/24Mg 1/4 0.139652 ¿ 0.000033. Given the restricted range of m25Mg obtained for bulk planetary material by the sample-standard bracketing technique and the...

  7. Multistep structural transition of hydrogen trititanate nanotubes into TiO2-B nanotubes: a comparison study between nanostructured and bulk materials

    International Nuclear Information System (INIS)

    H-trititanate nanotubes obtained by alkali hydrothermal treatment of TiO2 followed by proton exchange were compared to their bulk H2Ti3O7 counterpart with respect to their thermally induced structural transformation paths. As-synthesized and heat-treated samples were characterized by XRD, TEM/SAED, DSC and spectroscopy techniques, indicating that H2Ti3O7 nanotubes showed the same sequence of structural transformations as their bulk counterpart obtained by conventional solid state reaction. Nanostructured H2Ti3O7 converts into TiO2(B) via multistep transformation without losing its nanotubular morphology. The transformation occurs between 120 and 400 deg. C through topotactic mechanisms with the intermediate formation of nanostructured H2Ti6O13 and H2Ti12O25, which are more condensed layered titanates eventually rearranging to TiO2(B). Our results suggest that the intermediate tunnel structure H2Ti12O25 is the final layered intermediate phase, on which TiO2(B) nucleates and grows. The conversion of nanostructured TiO2(B) into anatase is completed at a much lower temperature than its bulk counterpart and is accompanied by loss of the nanotubular morphology

  8. The bulk radio expansion of Cassiopeia A

    International Nuclear Information System (INIS)

    Comparison, in the visibility plane, or radio observations of Cassiopeia A made at 151 MHz over a 2.3 yr interval indicates that the bulk of the radio emitting material has not been decelerated strongly

  9. Movimento e inativação do metribuzin em materiais de dois solos, sob diferentes densidades aparentes Movement and inactivation of metribuzin in two soil materials with different bulk densities

    Directory of Open Access Journals (Sweden)

    L.E.F. Fontes

    1980-06-01

    Full Text Available Numa série de ensaios em laboratório e casa-de-vegetação, estudou-se a mobilidade e a inativação do herbicida metribuzin em materiais de um Latossolo e de um Podzólico representativos de duas regiões do Estado de Minas Gerais, em função de diferentes densidades aparentes. Ensaios biológicos foram utilizados para medir a inativação e a mobilidade do metribuzin nos diferentes solos e densidades. A densidade aparente alterou de forma pronunciada a quantidade de herbicida lixiviado através das colunas dos materiais dos solos estudados. Quanto maior a densidade, menor a quantidade de herbicida lixiviado. A quantidade de herbicida que permaneceu biologicamente ativo ao longo da coluna foi diretamente relacionada com a densidade, em cada solo. A mobilidade do metribuzin no material do Latossolo foi maior que no de Podzólico, em consequência de maior atividade coloidal deste.The leaching and inactivation of metribuzin were studied with materials of two mineral soilsat different bulk densities. Plastic tubing of' 7.25 cm diameter and 10 cm height were filled up with different amounts of soil to get different bulk densities. One kg/ha of a.i. of metribuzin placed on the surface are a of the column was le ached through these soil colums using 250 ml of water. The cotyledon disk bioassay method was used to detect the metribuzin leachet. The biological active metribuzin in the soil colunn at different depths, and the inativation abil ity of the soils were determined using the assay with cucumber (Cucumis sativus L. as test-plant. The increase of bulk density reduced the leaching and enhanced the biologically active metribuzin in the soil column. Metribuzin was more mobil in the Red -yellow Lato ssol and more inactivated in the Red-yellow Podzolic soils.

  10. Ba1-xSrxCoyFe1-yO3-delta SOFC cathode materials : bulk properties, kinetics and mechanism of oxygen reduction

    OpenAIRE

    Wang, Lei

    2009-01-01

    This work is mainly concerned with the mixed conducting perovskite solid solution materials family Ba1-xSrxCoyFe1-yO3-delta (BSCF) which is discussed as solid oxide fuel cell (SOFC) cathode material. The aim is to get an improved understanding of the complex oxygen reduction reaction on such oxides in general, and in particular for the application as catalytically active cathode in SOFC. As a SOFC cathode candidate, the stability of BSCFs with regard to the application was first studied o...

  11. Preparation and optical and electrical evaluation of bulk SiO2 sonogel hybrid composites and vacuum thermal evaporated thin films prepared from molecular materials derived from (Fe, Co) metallic phthalocyanines and 1,8 dihydroxiantraquinone compounds

    International Nuclear Information System (INIS)

    Semiconducting molecular material of PcFe(CN)L1 and PcCo(CN)L1 (L1 = 1,8 dihydroxianthraquinone), PcFe(CN)L2 and PcCo(CN)L2 (L2 = double potassium salt of 1,8 dihydroxianthraquinone) have been successfully used to prepare thin film and bulk sol-gel hybrid optical materials. These samples were developed according to the vacuum thermal evaporation technique and the catalyst-free sonogel route, respectively. Thin films samples were deposited on Corning glass substrates and crystalline silicon wafers and were characterized by infrared (FTIR), Raman and ultraviolet-visible (UV-vis) spectroscopies. IR-spectroscopy and Raman studies unambiguously confirmed that the molecular material thin films exhibit the same intra-molecular bonds, which suggests that the thermal evaporation process does not alter these bonds significantly. These results show that it is possible to deposit molecular materials of PcFe(CN)L2 and PcCo(CN)L2 on Corning glass substrates and silicon wafers. From the UV-vis studies the optical band gap (Eg) was evaluated. The effect of temperature on conductivity was also evaluated in these samples. Finally, the studied molecular systems dissolved at different concentrations in tetrahydrofuran (THF) were successfully embedded into a highly pure SiO2 sonogel network generated via sonochemical reactions to form several solid state, optically active sol-gel hybrid glasses. By this method, homogeneous and stable hybrid monoliths suitable for optical characterization can be produced. The linear optical properties of these amorphous bulk structures were determined by the Brewster angle method and by absorption-, Raman- and photoluminescent (PL)-spectroscopies, respectively

  12. Preparation and optical and electrical evaluation of bulk SiO{sub 2} sonogel hybrid composites and vacuum thermal evaporated thin films prepared from molecular materials derived from (Fe, Co) metallic phthalocyanines and 1,8 dihydroxiantraquinone compounds

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Vergara, Maria Elena [Coordinacion de Ingenieria Mecatronica, Facultad de Ingenieria, Universidad Anahuac Mexico Norte. Avenida Universidad Anahuac 46, Col. Lomas Anahuac, 52786 Huixquilucan, Estado de Mexico (Mexico); Morales-Saavedra, Omar G. [Universidad Nacional Autonoma de Mexico, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, CCADET-UNAM, A.P. 70-186, Coyoacan, 04510 Mexico, D.F. (Mexico)], E-mail: omar.morales@ccadet.unam.mx; Ontiveros-Barrera, Fernando G.; Torres-Zuniga, Vicente; Ortega-Martinez, Roberto [Universidad Nacional Autonoma de Mexico, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, CCADET-UNAM, A.P. 70-186, Coyoacan, 04510 Mexico, D.F. (Mexico); Ortiz Rebollo, Armando [Universidad Nacional Autonoma de Mexico, Instituto de Investigaciones en Materiales, IIM-UNAM, A.P. 70-360, Coyoacan, 04510 Mexico, D.F. (Mexico)

    2009-02-25

    Semiconducting molecular material of PcFe(CN)L1 and PcCo(CN)L1 (L1 = 1,8 dihydroxianthraquinone), PcFe(CN)L2 and PcCo(CN)L2 (L2 = double potassium salt of 1,8 dihydroxianthraquinone) have been successfully used to prepare thin film and bulk sol-gel hybrid optical materials. These samples were developed according to the vacuum thermal evaporation technique and the catalyst-free sonogel route, respectively. Thin films samples were deposited on Corning glass substrates and crystalline silicon wafers and were characterized by infrared (FTIR), Raman and ultraviolet-visible (UV-vis) spectroscopies. IR-spectroscopy and Raman studies unambiguously confirmed that the molecular material thin films exhibit the same intra-molecular bonds, which suggests that the thermal evaporation process does not alter these bonds significantly. These results show that it is possible to deposit molecular materials of PcFe(CN)L2 and PcCo(CN)L2 on Corning glass substrates and silicon wafers. From the UV-vis studies the optical band gap (E{sub g}) was evaluated. The effect of temperature on conductivity was also evaluated in these samples. Finally, the studied molecular systems dissolved at different concentrations in tetrahydrofuran (THF) were successfully embedded into a highly pure SiO{sub 2} sonogel network generated via sonochemical reactions to form several solid state, optically active sol-gel hybrid glasses. By this method, homogeneous and stable hybrid monoliths suitable for optical characterization can be produced. The linear optical properties of these amorphous bulk structures were determined by the Brewster angle method and by absorption-, Raman- and photoluminescent (PL)-spectroscopies, respectively.

  13. Module 13: Bulk Packaging Shipments by Highway

    International Nuclear Information System (INIS)

    The Hazardous Materials Modular Training Program provides participating United States Department of Energy (DOE) sites with a basic, yet comprehensive, hazardous materials transportation training program for use onsite. This program may be used to assist individual program entities to satisfy the general awareness, safety training, and function specific training requirements addressed in Code of Federal Regulation (CFR), Title 49, Part 172, Subpart H -- ''Training.'' Module 13 -- Bulk Packaging Shipments by Highway is a supplement to the Basic Hazardous Materials Workshop. Module 13 -- Bulk Packaging Shipments by Highway focuses on bulk shipments of hazardous materials by highway mode, which have additional or unique requirements beyond those addressed in the ten module core program. Attendance in this course of instruction should be limited to those individuals with work experience in transporting hazardous materials utilizing bulk packagings and who have completed the Basic Hazardous Materials Workshop or an equivalent. Participants will become familiar with the rules and regulations governing the transportation by highway of hazardous materials in bulk packagings and will demonstrate the application of these requirements through work projects and examination

  14. Enhanced power factor and reduced thermal conductivity of a half-Heusler derivative Ti{sub 9}Ni{sub 7}Sn{sub 8}: A bulk nanocomposite thermoelectric material

    Energy Technology Data Exchange (ETDEWEB)

    Misra, D. K., E-mail: misradk@nplindia.org, E-mail: dakkmisra@gmail.com; Rajput, A.; Bhardwaj, A.; Chauhan, N. S. [CSIR Network of Institutes for Solar Energy, Division of Materials Physics and Engineering, CSIR National Physical Laboratory, Dr. Krishnan Marg, New Delhi 110012 (India); Singh, Sanjay [Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, D-01187 Dresden (Germany)

    2015-03-09

    We report a half-Heusler (HH) derivative Ti{sub 9}Ni{sub 7}Sn{sub 8} with VEC = 17.25 to investigate the structural changes for the optimization of high thermoelectric performance. The structural analysis reveals that the resulting material is a nanocomposite of HH and full-Heusler with traces of Ti{sub 6}Sn{sub 5} type-phase. Interestingly, present nanocomposite exhibits a significant decrease in thermal conductivity due to phonon scattering and improvement in the power factor due to combined effect of nanoinclusion-induced electron injection and electron scattering at interfaces, leading to a boost in the ZT value to 0.32 at 773 K, which is 60% higher than its bulk counterpart HH TiNiSn.

  15. Iron - based bulk amorphous alloys

    Directory of Open Access Journals (Sweden)

    R. Babilas

    2010-07-01

    Full Text Available Purpose: The paper presents a structure characterization, thermal and soft magnetic properties analysis of Fe-based bulk amorphous materials in as-cast state and after crystallization process. In addition, the paper gives some brief review about achieving, formation and structure of bulk metallic glasses as a special group of amorphous materials.Design/methodology/approach: The studies were performed on Fe72B20Si4Nb4 metallic glass in form of ribbons and rods. The amorphous structure of tested samples was examined by X-ray diffraction (XRD, transmission electron microscopy (TEM and scanning electron microscopy (SEM methods. The thermal properties of the glassy samples were measured using differential thermal analysis (DTA and differential scanning calorimetry (DSC. The magnetic properties contained initial and maximum magnetic permeability, coercive force and magnetic after-effects measurements were determined by the Maxwell-Wien bridge and VSM methods.Findings: The X-ray diffraction and transmission electron microscopy investigations revealed that the studied as-cast bulk metallic glasses in form of ribbons and rods were amorphous. Two stage crystallization process was observed for studied bulk amorphous alloy. The differences of crystallization temperature between ribbons and rods with chosen thickness are probably caused by different amorphous structures as a result of the different cooling rates in casting process. The SEM images showed that studied fractures could be classified as mixed fractures with indicated two zones contained “river” and “smooth” areas. The changing of chosen soft magnetic properties (μr, Bs, Hc obtained for samples with different thickness is a result of the non-homogenous amorphous structure of tested metallic glasses. The annealing process in temperature range from 373 to 773 K causes structural relaxation of tested amorphous materials, which leads to changes in their physical properties. The qualitative

  16. Evaluation and prevention of self-ignition and emission of combustion gases during storing bulk goods and landfill materials; Beurteilung und Verhinderung von Selbstentzuendung und Brandgasemission bei der Lagerung von Massenschuettguetern und Deponiestoffen

    Energy Technology Data Exchange (ETDEWEB)

    Schossig, Joerg; Berger, Anka; Malow, Marcus; Krause, Ulrich

    2010-05-27

    The authors of the contribution under consideration report on a new method for the risk assessment for self-ignition with the storage of bulk goods, landfill materials and recycling materials. This method consists of three components: (a) Experimental determination of the relevant physicochemical characteristics of the material; (b) Experimental determination of the reaction behaviour by means of thermal analysis behaviour; (c) Prediction of the self-ignition and the process of combustion. Fundamental realizations to the thermal behaviour and reaction behaviour of recycling storages were obtained. Thus, mixtures from plastics with cellulose containing or fibre-like materials or with inert materials, respectively, have an increased danger to self-ignition in comparison to pure plastics. A dangerous heat release also is observed with very small portions of inflammable materials. Under consideration of heterogeneous distribution of the inflammable components, the ignition can be transferred between inflammable inclusions. By means of a mathematical model, self-inflammation processes can be protected in arbitrary arrangements of the recycling storages. [German] Im Ergebnis des Vorhabens steht fuer die praktische Anwendung eine wissenschaftlich fundierte Methode der Gefahrenbewertung fuer Selbstentzuendungsvorgaenge bei der Lagerung von Massenschuettguetern, Deponiestoffen und Recyclingmaterialien zur Verfuegung. Diese Methode besteht aus drei Bestandteilen: - Experimentelle Bestimmung der relevanten physiko-chemischen Eigenschaften des Materials, - Experimentelle Bestimmung des Reaktionsverhaltens mittels thermischer Analyseverfahren, - Vorhersage der Selbstentzuendung und des Brandverlaufes durch numerische Simulation anhand der realen Geometrie der Lageranordnung. Eine solche Methode wurde bisher nicht systematisch angewendet, weshalb sowohl bei der Erstellung von Brandschutzkonzepten durch die Betreiber von Deponien oder Recyclinglagern als auch bei der Genehmigung

  17. On metallic gratings coated conformally with isotropic negative-phase-velocity materials

    Energy Technology Data Exchange (ETDEWEB)

    Inchaussandague, Marina E. [GEA-Grupo de Electromagnetismo Aplicado, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina); CONICET-Consejo Nacional de Investigaciones Cientificas y Tecnicas, Rivadavia 1917, Buenos Aires (Argentina)], E-mail: mei@df.uba.ar; Lakhtakia, Akhlesh [CATMAS-Computational and Theoretical Materials Sciences Group, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802-6812 (United States)], E-mail: akhlesh@psu.edu; Depine, Ricardo A. [GEA-Grupo de Electromagnetismo Aplicado, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina); CONICET-Consejo Nacional de Investigaciones Cientificas y Tecnicas, Rivadavia 1917, Buenos Aires (Argentina)], E-mail: rdep@df.uba.ar

    2008-03-31

    Application of the differential method (also called the C method) to plane-wave diffraction by a perfectly conducting, sinusoidally corrugated metallic grating coated with a linear, homogeneous, isotropic, lossless dielectric-magnetic material shows that coating materials with negative index of refraction may deliver enhanced maximum nonspecular reflection efficiencies in comparison to coating materials with positive index of refraction.

  18. Organic hybrid planar-nanocrystalline bulk heterojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Forrest, Stephen R.; Yang, Fan

    2013-04-09

    A photosensitive optoelectronic device having an improved hybrid planar bulk heterojunction includes a plurality of photoconductive materials disposed between the anode and the cathode. The photoconductive materials include a first continuous layer of donor material and a second continuous layer of acceptor material. A first network of donor material or materials extends from the first continuous layer toward the second continuous layer, providing continuous pathways for conduction of holes to the first continuous layer. A second network of acceptor material or materials extends from the second continuous layer toward the first continuous layer, providing continuous pathways for conduction of electrons to the second continuous layer. The first network and the second network are interlaced with each other. At least one other photoconductive material is interspersed between the interlaced networks. This other photoconductive material or materials has an absorption spectra different from the donor and acceptor materials.

  19. Bulk chemicals from biomass

    NARCIS (Netherlands)

    Haveren, van J.; Scott, E.L.; Sanders, J.P.M.

    2008-01-01

    Given the current robust forces driving sustainable production, and available biomass conversion technologies, biomass-based routes are expected to make a significant impact on the production of bulk chemicals within 10 years, and a huge impact within 20-30 years. In the Port of Rotterdam there is a

  20. Heat transport in bulk/nanoporous/bulk silicon devices

    Energy Technology Data Exchange (ETDEWEB)

    Criado-Sancho, M. [Departamento de Ciencias y Técnicas Físicoquimicas, Facultad de Ciencias, UNED, Senda del Rey 9, 20040 Madrid (Spain); Jou, D., E-mail: David.Jou@uab.cat [Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia (Spain); Institut d' Estudis Catalans, Carme 47, 08001 Barcelona, Catalonia (Spain)

    2013-02-04

    We study heat transport in bulk/nanoporous/bulk silicon devices; we show that, despite bulk/nanoporous devices may act as thermal rectifiers, the non-linear aspects of their joint thermal conductance are not strong enough to lead to a negative differential thermal resistance, necessary to allow bulk/nanoporous/bulk Si devices to act as thermal transistors. Furthermore, we explicitly study the effective thermal conductivity of the mentioned devices for several temperatures, geometries, porosities, and pore size.

  1. Synthesis of Bulk Superconducting Magnesium Diboride

    Directory of Open Access Journals (Sweden)

    Margie Olbinado

    2002-06-01

    Full Text Available Bulk polycrystalline superconducting magnesium diboride, MgB2, samples were successfully prepared via a one-step sintering program at 750°C, in pre Argon with a pressure of 1atm. Both electrical resistivity and magnetic susceptibility measurements confirmed the superconductivity of the material at 39K, with a transition width of 5K. The polycrystalline nature, granular morphology, and composition of the sintered bulk material were confirmed using X-ray diffractometry (XRD, scanning electron microscopy (SEM, and energy dispersive X-ray analysis (EDX.

  2. Development of superconductor bulk for superconductor bearing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chan Joong; Jun, Byung Hyuk; Park, Soon Dong (and others)

    2008-08-15

    Current carrying capacity is one of the most important issues in the consideration of superconductor bulk materials for engineering applications. There are numerous applications of Y-Ba-Cu-O (YBCO) bulk superconductors e.g. magnetic levitation train, flywheel energy storage system, levitation transportation, lunar telescope, centrifugal device, magnetic shielding materials, bulk magnets etc. Accordingly, to obtain YBCO materials in the form of large, single crystals without weak-link problem is necessary. A top seeded melt growth (TSMG) process was used to fabricate single crystal YBCO bulk superconductors. The seeded and infiltration growth (IG) technique was also very promising method for the synthesis of large, single-grain YBCO bulk superconductors with good superconducting properties. 5 wt.% Ag doped Y211 green compacts were sintered at 900 .deg. C {approx} 1200 .deg.C and then a single crystal YBCO was fabricated by an infiltration method. A refinement and uniform distribution of the Y211 particles in the Y123 matrix were achieved by sintering the Ag-doped samples. This enhancement of the critical current density was ascribable to a fine dispersion of the Y211 particles, a low porosity and the presence of Ag particles. In addition, we have designed and manufactured large YBCO single domain with levitation force of 10-13 kg/cm{sup 2} using TSMG processing technique.

  3. Bulk Moisture and Salinity Sensor

    Science.gov (United States)

    Nurge, Mark; Monje, Oscar; Prenger, Jessica; Catechis, John

    2013-01-01

    Measurement and feedback control of nutrient solutions in plant root zones is critical to the development of healthy plants in both terrestrial and reduced-gravity environments. In addition to the water content, the amount of fertilizer in the nutrient solution is important to plant health. This typically requires a separate set of sensors to accomplish. A combination bulk moisture and salinity sensor has been designed, built, and tested with different nutrient solutions in several substrates. The substrates include glass beads, a clay-like substrate, and a nutrient-enriched substrate with the presence of plant roots. By measuring two key parameters, the sensor is able to monitor both the volumetric water content and salinity of the nutrient solution in bulk media. Many commercially available moisture sensors are point sensors, making localized measurements over a small volume at the point of insertion. Consequently, they are more prone to suffer from interferences with air bubbles, contact area of media, and root growth. This makes it difficult to get an accurate representation of true moisture content and distribution in the bulk media. Additionally, a network of point sensors is required, increasing the cabling, data acquisition, and calibration requirements. measure the dielectric properties of a material in the annular space of the vessel. Because the pore water in the media often has high salinity, a method to measure the media moisture content and salinity simultaneously was devised. Characterization of the frequency response for capacitance and conductance across the electrodes was completed for 2-mm glass bead media, 1- to 2-mm Turface (a clay like media), and 1- to 2-mm fertilized Turface with the presence of root mass. These measurements were then used to find empirical relationships among capacitance (C), the dissipation factor (D), the volumetric water content, and the pore water salinity.

  4. Nonlinear variation influence factors for induced airflow of bulk materials in transfer station%转运点落料诱导气流非线性变化影响因素

    Institute of Scientific and Technical Information of China (English)

    李小川; 李强; 张栋; 胡亚非; 熊建军; 罗会清; 贾彬彬; 胡海彬

    2014-01-01

    转运点诱导气流是散料输送过程扬尘的主要诱因,本文以半封闭转运点为研究对象,通过对落料质量流量mp、有效诱导气流量Q、落料高度h及密闭罩阻力系数ξ等的研究,探讨转运点落料诱导气流非线性变化影响因素。结果表明:诱导气流随物料质量流量增加而增加;受物料相互作用对气流流动的影响和落料管有效流动空间变化影响,有效诱导气流随质量流量增加而减小,在量值上与物料质量流量的-0.77次方近似成正比;转运点落差的有限性使落料过程处于加速阶段,物料曳力系数处于Allen区,诱导气流速度随落料高度的变化趋势基本相同;对平均阻力系数ξ=2.12的密闭罩系统,诱导气流速度与下落高度的0.86次方近似成正比;物料下落初期颗粒间相互碰撞、接触等作用较强,对3.6~11.1 mm的落料,诱导气流随粒度增大有减小趋势,但关联性较弱。%Induced airflow of free-falling particles process serving as the chief temptation of dust fugitive in transfer station of conveying process for bulk materials. The semi-closed transfer station was chosen as the study object in the present paper. Nonlinear variation influence factors for induced airflow were explored through the study of mass flow rate of bulk material mp, specific induced air flow Q, drop height h and resistance coefficient of suction hoodξ. The primary conclusions are as follows: With the mass flow increasing, the induced airflow increases, and the specific induced air flow decreases due to the influences of the interaction between the particles for airstream and the change of effective flow space of blanking tube. The specific induced air flow is found to be proportional to the mass flow raised to the power of approximately -0.77. Owing to the finiteness of the drop height of the transfer station the falling particles is in the acceleration phase all along. The drag

  5. Wormholes in Bulk Viscous Cosmology

    OpenAIRE

    Jamil, Mubasher

    2008-01-01

    We investigate the effects of the accretion of phantom energy with non-zero bulk viscosity onto a Morris-Thorne wormhole. We have found that if the bulk viscosity is large then the mass of wormhole increases rapidly as compared to small or zero bulk viscosity.

  6. Remedial investigations for quarry bulk wastes

    International Nuclear Information System (INIS)

    The US Department of Energy proposes, as a separate operable unit of the Weldon Spring Site Remedial Action Project, to remove contaminated bulk wastes from the Weldon Spring quarry and transport them approximately four miles to the chemical plant portion of the raffinate pits and chemical plant area. The wastes will be held in temporary storage prior to the record of decision for the overall remedial action. The decision on the ultimate disposal of these bulk wastes will be included as part of the decision for management of the waste materials resulting from remedial action activities at the raffinate pits and chemical plant area. 86 refs., 71 figs., 83 tabs

  7. Nanocomposite RE-Ba-Cu-O bulk superconductors

    OpenAIRE

    Iida, Kazumasa

    2016-01-01

    Nanocomposite oxide high-temperature bulk superconductors can be used as quasi-magnets. Thanks to the recent progress of material processing, quasi-magnet with 26 mm diameter can generate a large field of 17.6 T at 26 K. These results are highly attractive for applications, involving levitation of permanent magnets on the bulk superconductors. Indeed, several other applications such as motors and magnetic resonance microscope using bulk superconductors have been proposed and demonstrated. In ...

  8. The Incredible Bulk

    CERN Document Server

    Fukushima, Keita; Kumar, Jason; Sandick, Pearl; Yamamoto, Takahiro

    2014-01-01

    Recent experimental results from the LHC have placed strong constraints on the masses of colored superpartners. The MSSM parameter space is also constrained by the measurement of the Higgs boson mass, and the requirement that the relic density of lightest neutralinos be consistent with observations. Although large regions of the MSSM parameter space can be excluded by these combined bounds, leptophilic versions of the MSSM can survive these constraints. In this paper we consider a scenario in which the requirements of minimal flavor violation, vanishing $CP$-violation, and mass universality are relaxed, specifically focusing on scenarios with light sleptons. We find a large region of parameter space, analogous to the original bulk region, for which the lightest neutralino is a thermal relic with an abundance consistent with that of dark matter. We find that these leptophilic models are constrained by measurements of the magnetic and electric dipole moments of the electron and muon, and that these models have ...

  9. Bulk muscles, loose cables.

    Science.gov (United States)

    Liyanage, Chamari R D G; Kodali, Venkata

    2014-01-01

    The accessibility and usage of body building supplements is on the rise with stronger internet marketing strategies by the industry. The dangers posed by the ingredients in them are underestimated. A healthy young man came to the emergency room with palpitations and feeling unwell. Initial history and clinical examination were non-contributory to find the cause. ECG showed atrial fibrillation. A detailed history for any over the counter or herbal medicine use confirmed that he was taking supplements to bulk muscle. One of the components in these supplements is yohimbine; the onset of symptoms coincided with the ingestion of this product and the patient is symptom free after stopping it. This report highlights the dangers to the public of consuming over the counter products with unknown ingredients and the consequential detrimental impact on health. PMID:25326558

  10. Engineering nanostructural routes for enhancing thermoelectric performance: bulk to nanoscale

    Directory of Open Access Journals (Sweden)

    Rajeshkumar eMohanraman

    2015-11-01

    Full Text Available Thermoelectricity is a very important physical property, especially its significance in heat-electricity conversion. If thermoelectric devices can be effectively applied to the recovery of the renewable energies, such as waste heat and solar energy, the energy shortage and global warming issues may be greatly relieved. This review focusses recent developments on the thermoelectric performance of a low-dimensional material, bulk nanostructured materials, conventional bulk materials etc. Particular emphasis is given on, how the nanostructure in nanostructured composites, confinement effects in one-dimensional nanowires and doping effects in conventional bulk composites plays an important role in ZT enhancement.

  11. Engineering Nanostructural Routes for Enhancing Thermoelectric Performance: Bulk to Nanoscale

    Science.gov (United States)

    Mohanraman, Rajeshkumar; Lan, Tian-Wey; Hsiung, Te-Chih; Amada, Dedi; Lee, Ping-Chung; Ou, Min-Nan; Chen, Yang-Yuan

    2015-01-01

    Thermoelectricity is a very important phenomenon, especially its significance in heat-electricity conversion. If thermoelectric devices can be effectively applied to the recovery of the renewable energies, such as waste heat and solar energy, the energy shortage, and global warming issues may be greatly relieved. This review focusses recent developments on the thermoelectric performance of a low-dimensional material, bulk nanostructured materials, conventional bulk materials etc. Particular emphasis is given on, how the nanostructure in nanostructured composites, confinement effects in one-dimensional nanowires and doping effects in conventional bulk composites plays an important role in ZT enhancement. PMID:26913280

  12. 27 CFR 24.301 - Bulk still wine record.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Bulk still wine record. 24..., DEPARTMENT OF THE TREASURY LIQUORS WINE Records and Reports § 24.301 Bulk still wine record. A proprietor who produces or receives still wine in bond, (including wine intended for use as distilling material or...

  13. Inflation from bulk viscosity

    CERN Document Server

    Bamba, Kazuharu

    2015-01-01

    We explore the perfect fluid description of the inflationary universe. In particular, we investigate a fluid model with the bulk-viscosity term. We find that the three observables of inflationary cosmology: the spectral index of the curvature perturbations, the tensor-to-scalar ratio of the density perturbations, and the running of the spectral index, can be consistent with the recent Planck results. We also reconstruct the explicit equation of state (EoS) of the viscous fluid from the spectral index of the curvature perturbations compatible with the Planck analysis. In the reconstructed models of the viscous fluid, the tensor-to-scalar ratio of the density perturbations can satisfy the constraints obtained from the Planck satellite. The running of the spectral index can explain the Planck data. In addition, it is demonstrated that in the reconstructed models of the viscous fluid, the graceful exit from inflation can be realized. Furthermore, we show that the singular inflation can occur in the viscous fluid ...

  14. Performance and applications of quench melt-growth bulk magnets

    Science.gov (United States)

    Nariki, S.; Teshima, H.; Morita, M.

    2016-03-01

    This paper describes the progress in quench melt-growth (QMG) bulk magnets, developed by the Nippon Steel & Sumitomo Metal Corporation, which consist of single crystalline RE123 phase and finely dispersed RE211 particles. QMG bulks can trap high magnetic fields. The field-trapping ability of QMG bulks is largely increased with an improvement in its J c and size, promising the realization of various applications such as flywheel energy-storage systems, ship motors, NMR/MRI spectrometers, wind-power generators and so on. Intensive research has revealed that the optimal RE element is different depending on application requirements. Gd-QMG bulk is the most promising material for several high-field engineering applications. The trapped magnetic field of Gd-QMG bulk 60 mm in diameter at 77 K is twice as large as that of Y-QMG bulk with a similar size due to its excellent J c properties. The large Gd-based QMG bulks up to 150 mm in diameter are fabricated by incorporating the RE compositional gradient method. Compact NMR/MRI spectrometers are one of the promising applications of bulk superconductors. Eu-QMG bulks are suitable for NMR magnets. NMR applications require extremely homogeneous magnetic fields. In the Eu-system, the small paramagnetic moment of a Eu ion compared to a Gd ion improves the field homogeneity in the bulk. For the application of current leads, Dy-based QMG is available by utilizing a low thermal conductivity.

  15. Bulk metallic glass for low noise fluxgate Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The team of Prime Photonics, Virginia Tech, and Utron Kinetics propose to demonstrate a method for fabrication of a bulk, amorphous, cobalt-rich material that...

  16. Semi-Empirical formula for describing the temperature dependence of the bulk modulus

    CERN Document Server

    Garai, J

    2006-01-01

    The product of the bulk modulus and the molar volume is constant for materials with the same crystal structure. Using this correlation a semi-empirical formula is suggested for describing the temperature dependence of the bulk modulus.

  17. Induction detection of concealed bulk banknotes

    International Nuclear Information System (INIS)

    Bulk cash smuggling is a serious issue that has grown in volume in recent years. By building on the magnetic characteristics of paper currency, induction sensing is found to be capable of quickly detecting large masses of banknotes. The results show that this method is effective in detecting bulk cash through concealing materials such as plastics, cardboards, fabrics and aluminum foil. The significant difference in the observed phase between the received signals caused by conducting materials and ferrite compounds, found in banknotes, provides a good indication that this process can overcome the interference by metal objects in a real sensing application. This identification strategy has the potential to not only detect the presence of banknotes, but also the number, while still eliminating false positives caused by metal objects

  18. Theoretical analysis of ac losses in high temperature superconducting bulks

    International Nuclear Information System (INIS)

    Ac loss behavior in HTS bulk materials is studied by developing an analytic method. The self-heating effect on the distributions of temperature in HTS bulks has been calculated. A critical frequency which sets the upper limit for driving frequency of the external field in sustaining a superconducting state is obtained. Our model provides useful information of understanding the experimental phenomena, including an anomalous ac loss behavior, a retardation of the inner field respect to the external ac field, etc., in HTS bulk materials

  19. Mining the bulk positron lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Aourag, H.; Guittom, A. [Centre de Recherche Nucleaire d' Alger (CRNA), Alger Gare - Algiers (Algeria)

    2009-02-15

    We introduce a new approach to investigate the bulk positron lifetimes of new systems based on data-mining techniques. Through data mining of bulk positron lifetimes, we demonstrate the ability to predict the positron lifetimes of new semiconductors on the basis of available semiconductor data already studied. Informatics techniques have been applied to bulk positron lifetimes for different tetrahedrally bounded semiconductors in order to discover computational design rules. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Mining the bulk positron lifetime

    International Nuclear Information System (INIS)

    We introduce a new approach to investigate the bulk positron lifetimes of new systems based on data-mining techniques. Through data mining of bulk positron lifetimes, we demonstrate the ability to predict the positron lifetimes of new semiconductors on the basis of available semiconductor data already studied. Informatics techniques have been applied to bulk positron lifetimes for different tetrahedrally bounded semiconductors in order to discover computational design rules. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Advances in bulk port development

    Energy Technology Data Exchange (ETDEWEB)

    Soros, P. (Soros Associates Consulting Engineers, New York, NY (USA))

    1991-03-01

    The article features several recently developed bulk ports which illustrate aspects of new technology or concepts in maritime transport. Low handling capacity bulk terminals at Ponta da Madeira, Brazil and Kooragang Island, Australia and the low-cost bulk port at Port of Corpus Christi, Texas are described. Operations at the ports of Pecket and Tocopilla in Chile, which had special technical problems, are mentioned. Coal terminals at Port Kembla, Australia and St. Johns River in Florid Jacksonville, Florida are featured as examples of terminals which had to be designed to meet high environmental standards. 13 refs., 2 figs., 14 photos.

  2. Multilayer Integrated Film Bulk Acoustic Resonators

    CERN Document Server

    Zhang, Yafei

    2013-01-01

    Multilayer Integrated Film Bulk Acoustic Resonators mainly introduces the theory, design, fabrication technology and application of a recently developed new type of device, multilayer integrated film bulk acoustic resonators, at the micro and nano scale involving microelectronic devices, integrated circuits, optical devices, sensors and actuators, acoustic resonators, micro-nano manufacturing, multilayer integration, device theory and design principles, etc. These devices can work at very high frequencies by using the newly developed theory, design, and fabrication technology of nano and micro devices. Readers in fields of IC, electronic devices, sensors, materials, and films etc. will benefit from this book by learning the detailed fundamentals and potential applications of these advanced devices. Prof. Yafei Zhang is the director of the Ministry of Education’s Key Laboratory for Thin Films and Microfabrication Technology, PRC; Dr. Da Chen was a PhD student in Prof. Yafei Zhang’s research group.

  3. Bulk laundry monitoring system

    International Nuclear Information System (INIS)

    Protective wear (like boiler suits, hand gloves etc.) is essential while handling radioactive material in plants/laboratories. During the course of work, it is quite possible that protective wear may get contaminated. These protective wears are packed in laundry bags and send to Decontamination Centre (DC). There is a need for monitoring the laundry bags at the time of receipt, as well as before dispatch to respective locations to comply with AERB guidelines, To avoid cross contamination during wash cycle, contaminated bags (> 0.5 mR/h on surface) need to be segregated. Present paper describes the development of such system for monitoring surface dose rate on bags at the time of receipt. The system installed at ETP after calibration, effectively segregates the contaminated bags from the rest and prevents from cross contamination during wash cycle. Reduction in man-rem consumption due to semi automatic monitoring. Improved sensitivity due to good geometry, long counting time, background and attenuation corrections. Optimum utilization of decontamination chemicals based on level of contamination and keeping track of its inventory. Generation of decontamination process data base for improvement

  4. Bulk Nuclear Properties from Reactions

    OpenAIRE

    Danielewicz, P.

    2002-01-01

    Extraction of bulk nuclear properties by comparing reaction observables to results from semiclassical transport-model simulations is discussed. Specific properties include the nuclear viscosity, incompressibility and constraints on the nuclear pressure at supranormal densities.

  5. Bulk charges in eleven dimensions

    CERN Document Server

    Hawking, Stephen William

    1998-01-01

    Eleven dimensional supergravity has electric type currents arising from the Chern-Simon and anomaly terms in the action. However the bulk charge integrates to zero for asymptotically flat solutions with topological trivial spatial sections. We show that by relaxing the boundary conditions to generalisations of the ALE and ALF boundary conditions in four dimensions one can obtain static solutions with a bulk charge preserving between 1/16 and 1/4 of the supersymmetries. One can introduce membranes with the same sign of charge into these backgrounds. This raises the possibility that these generalized membranes might decay quantum mechanically to leave just a bulk distribution of charge. Alternatively and more probably, a bulk distribution of charge can decay into a collection of singlely charged membranes. Dimensional reductions of these solutions lead to novel representations of extreme black holes in four dimensions with up to four charges. We discuss how the eleven-dimensional Kaluza-Klein monopole wrapped a...

  6. Simple top-down preparation of magnetic Bi0.9Gd0.1Fe1−xTixO3 nanoparticles by ultrasonication of multiferroic bulk material

    DEFF Research Database (Denmark)

    Basith, M. A.; Ngo, Duc-The; Quader, A.;

    2014-01-01

    We present a simple technique to synthesize ultrafine nanoparticles directly from bulk multiferroic perovskitepowder. The starting materials, which were ceramic pellets of the nominal compositions Bi0.9Gd0.1-Fe1−xTixO3 (x = 0.00–0.20), were prepared initially by a solid state reaction technique......-crystalline nanoparticles with a meansize of 11–13 nm. A significant improvement in the magnetic behavior of Bi0.9Gd0.1Fe1−xTixO3 nanoparticlescompared to their bulk counterparts was observed at room temperature. This sonication technique may beconsidered as a simple and promising route to prepare ultrafine nanoparticles...

  7. Experimental study of bulk storage ignition by hot points

    OpenAIRE

    Janes, Agnès; Carson, Douglas

    2013-01-01

    International audience An experimental study of ignition risk due to hot points in the storage of bulk materials is required to ensure fire safety. Many parameters are involved in this phenomenon: nature of the material, storage volume and temperature, type and size of hot point, etc. The aim of this study is to determine critical ignition temperatures of hot spots embedded in powder materials for different conditions and with several types of hot points. Materials selected for this study ...

  8. Development of Bulk Nanocrystalline Cemented Tungsten Carbide for Industrial Applicaitons

    Energy Technology Data Exchange (ETDEWEB)

    Z. Zak Fang, H. Y. Sohn

    2009-03-10

    This report contains detailed information of the research program entitled "Development of Bulk Nanocrystalline Cemented Tungsten Carbide Materials for Industrial Applications". The report include the processes that were developed for producing nanosized WC/Co composite powders, and an ultrahigh pressure rapid hot consolidation process for sintering of nanosized powders. The mechanical properties of consolidated materials using the nanosized powders are also reported.

  9. Negative-Index Media for Matter-Wave Optics

    Science.gov (United States)

    Baudon, J.; Hamamda, M.; Grucker, J.; Boustimi, M.; Perales, F.; Dutier, G.; Ducloy, M.

    2009-04-01

    We consider the extension of optical metamaterials to matter waves and then the down scaling of metaoptics to nanometric wavelengths. We show that the generic property of pulsed comoving magnetic fields allows us to fashion the wave-number dependence of the atomic phase shift. It can be used to produce a transient negative group velocity of an atomic wave packet, which results into a negative refraction of the matter wave. Application to slow metastable argon atoms Ar*(P23) shows that the device is able to operate either as an efficient beam splitter or an atomic metalens.

  10. Soft 3D acoustic metamaterial with negative index.

    Science.gov (United States)

    Brunet, Thomas; Merlin, Aurore; Mascaro, Benoit; Zimny, Kevin; Leng, Jacques; Poncelet, Olivier; Aristégui, Christophe; Mondain-Monval, Olivier

    2015-04-01

    Many efforts have been devoted to the design and achievement of negative-refractive-index metamaterials since the 2000s. One of the challenges at present is to extend that field beyond electromagnetism by realizing three-dimensional (3D) media with negative acoustic indices. We report a new class of locally resonant ultrasonic metafluids consisting of a concentrated suspension of macroporous microbeads engineered using soft-matter techniques. The propagation of Gaussian pulses within these random distributions of 'ultra-slow' Mie resonators is investigated through in situ ultrasonic experiments. The real part of the acoustic index is shown to be negative (up to almost - 1) over broad frequency bandwidths, depending on the volume fraction of the microbeads as predicted by multiple-scattering calculations. These soft 3D acoustic metamaterials open the way for key applications such as sub-wavelength imaging and transformation acoustics, which require the production of acoustic devices with negative or zero-valued indices. PMID:25502100

  11. Soft 3D acoustic metamaterial with negative index

    Science.gov (United States)

    Brunet, Thomas; Merlin, Aurore; Mascaro, Benoit; Zimny, Kevin; Leng, Jacques; Poncelet, Olivier; Aristégui, Christophe; Mondain-Monval, Olivier

    2015-04-01

    Many efforts have been devoted to the design and achievement of negative-refractive-index metamaterials since the 2000s. One of the challenges at present is to extend that field beyond electromagnetism by realizing three-dimensional (3D) media with negative acoustic indices. We report a new class of locally resonant ultrasonic metafluids consisting of a concentrated suspension of macroporous microbeads engineered using soft-matter techniques. The propagation of Gaussian pulses within these random distributions of ‘ultra-slow’ Mie resonators is investigated through in situ ultrasonic experiments. The real part of the acoustic index is shown to be negative (up to almost - 1) over broad frequency bandwidths, depending on the volume fraction of the microbeads as predicted by multiple-scattering calculations. These soft 3D acoustic metamaterials open the way for key applications such as sub-wavelength imaging and transformation acoustics, which require the production of acoustic devices with negative or zero-valued indices.

  12. Negative-Index Media for Matter-Wave Optics

    International Nuclear Information System (INIS)

    We consider the extension of optical metamaterials to matter waves and then the down scaling of metaoptics to nanometric wavelengths. We show that the generic property of pulsed comoving magnetic fields allows us to fashion the wave-number dependence of the atomic phase shift. It can be used to produce a transient negative group velocity of an atomic wave packet, which results into a negative refraction of the matter wave. Application to slow metastable argon atoms Ar*(3P2) shows that the device is able to operate either as an efficient beam splitter or an atomic metalens

  13. Substantial bulk photovoltaic effect enhancement via nanolayering.

    Science.gov (United States)

    Wang, Fenggong; Young, Steve M; Zheng, Fan; Grinberg, Ilya; Rappe, Andrew M

    2016-01-01

    Spontaneous polarization and inversion symmetry breaking in ferroelectric materials lead to their use as photovoltaic devices. However, further advancement of their applications are hindered by the paucity of ways of reducing bandgaps and enhancing photocurrent. By unravelling the correlation between ferroelectric materials' responses to solar irradiation and their local structure and electric polarization landscapes, here we show from first principles that substantial bulk photovoltaic effect enhancement can be achieved by nanolayering PbTiO3 with nickel ions and oxygen vacancies ((PbNiO2)x(PbTiO3)(1-x)). The enhancement of the total photocurrent for different spacings between the Ni-containing layers can be as high as 43 times due to a smaller bandgap and photocurrent direction alignment for all absorption energies. This is due to the electrostatic effect that arises from nanolayering. This opens up the possibility for control of the bulk photovoltaic effect in ferroelectric materials by nanoscale engineering of their structure and composition. PMID:26791545

  14. Fabrication of bulk metallic glasses by centrifugal casting method

    Directory of Open Access Journals (Sweden)

    R. Nowosielski

    2007-01-01

    Full Text Available Purpose: The aim of the present work is characterization of the centrifugal casting method, apparatus andproduced amorphous materials, which are also known as bulk metallic glassesDesign/methodology/approach: The studied centrifugal casting system consists of two main parts: castingapparatus and injection system of molten alloy. The described centrifugal casting method was presented bypreparing a casting apparatus “CentriCast – 5”. The apparatus includes a cylindrical copper mold, which isrotated by a motor. The transmission allows to changing the speed of rotating mold.Findings: Bulk metallic glasses are a novel class of engineering materials, which exhibit excelent mechanical,thermal, magnetic and corrosion properties. Centrifugal casting is a useful method to produce bulk amorphousmaterials in form of rings, tubes or cylindrical parts. Presented centrifugal casting method and casting apparatushas been prepared to fabricate the samples of bulk metallic glass in form of rings with an outer diameter of 25mm and controlled thicknesses by changing the weight of the molten alloy.Research limitations/implications: Studied centrifugal casting method and casting apparatus has beenprepared to fabricate the samples of bulk metallic glass. For future research a characterization of microstructureand properties of prepared material will be performed.Practical implications: The centrifugal casting is a useful process to produce bulk amorphous materials in formof rings, tubes or graded amorphous matrix composites. It seems to be a very simple method, which allows toobtain BMG materials.Originality/value: The centrifugal casting method allows to produce bulk amorphous rings with thicknessabove 1-mm.

  15. Looking for a bulk point

    CERN Document Server

    Maldacena, Juan; Zhiboedov, Alexander

    2015-01-01

    We consider Lorentzian correlators of local operators. In perturbation theory, singularities occur when we can draw a position-space Landau diagram with null lines. In theories with gravity duals, we can also draw Landau diagrams in the bulk. We argue that certain singularities can arise only from bulk diagrams, not from boundary diagrams. As has been previously observed, these singularities are a clear diagnostic of bulk locality. We analyze some properties of these perturbative singularities and discuss their relation to the OPE and the dimensions of double-trace operators. In the exact nonperturbative theory, we expect no singularity at these locations. We prove this statement in 1+1 dimensions by CFT methods.

  16. Gamma probe dry bulk densities

    International Nuclear Information System (INIS)

    The gamma density probe is a useful instrument for measuring water content in small volumes of soil. Essentially, the gamma probe measures the density of the soil and water between a source and a detector. To transpose the gamma densities into water content, the dry bulk density of the soil is needed. A nondestructive method for estimating dry bulk densities for use with the gamma probe is proposed. The procedure is based on the assumption that water content values in a field dry condition were more stable than the dry bulk density values and could be transferred from one point to another. The procedure was successfully used on three areas in Reynolds Creek Experimental Watershed in southwest Idaho. (U.S.)

  17. Bulk Viscosity of Interacting Hadrons

    OpenAIRE

    Wiranata, A.; M. Prakash

    2009-01-01

    We show that first approximations to the bulk viscosity $\\eta_v$ are expressible in terms of factors that depend on the sound speed $v_s$, the enthalpy, and the interaction (elastic and inelastic) cross section. The explicit dependence of $\\eta_v$ on the factor $(\\frac 13 - v_s^2)$ is demonstrated in the Chapman-Enskog approximation as well as the variational and relaxation time approaches. The interesting feature of bulk viscosity is that the dominant contributions at a given temperature ari...

  18. Bulk Viscosity of Interacting Hadrons

    CERN Document Server

    Wiranata, A

    2009-01-01

    We show that first approximations to the bulk viscosity $\\eta_v$ are expressible in terms of factors that depend on the sound speed $v_s$, the enthalpy, and the interaction (elastic and inelastic) cross section. The explicit dependence of $\\eta_v$ on the factor $(\\frac 13 - v_s^2)$ is demonstrated in the Chapman-Enskog approximation as well as the variational and relaxation time approaches. The interesting feature of bulk viscosity is that the dominant contributions at a given temperature arise from particles which are neither extremely nonrelativistic nor extremely relativistic. Numerical results for a model binary mixture are reported.

  19. Bulk charges in eleven dimensions

    Science.gov (United States)

    Hawking, S. W.; Taylor-Robinson, M. M.

    1998-07-01

    Eleven dimensional supergravity has electric type currents arising from the Chern-Simon and anomaly terms in the action. However the bulk charge integrates to zero for asymptotically flat solutions with topological trivial spatial sections. We show that by relaxing the boundary conditions to generalisations of the ALE and ALF boundary conditions in four dimensions one can obtain static solutions with a bulk charge. Solutions involving anomaly terms preserve between 1/16 and 1/4 of the supersymmetries but Chern-Simons fluxes generally break all of the remaining supersymmetry. One can introduce membranes with the same sign of charge into these backgrounds. This raises the possibility that these generalized membranes might decay quantum mechanically to leave just a bulk distribution of charge. Alternatively and more probably, a bulk distribution of charge can decay into a collection of singly charged membranes. Dimensional reductions of these solutions lead to novel representations of extreme black holes in four dimensions with up to four charges. We discuss how the eleven-dimensional Kaluza-Klein monopole wrapped around a space with non-zero first Pontryagin class picks up an electric charge proportional to the Pontryagin number.

  20. Bulk viscosity and deflationary universes

    CERN Document Server

    Lima, J A S; Waga, I

    2007-01-01

    We analyze the conditions that make possible the description of entropy generation in the new inflationary model by means of a nearequilibrium process. We show that there are situations in which the bulk viscosity cannot describe particle production during the coherent field oscillations phase.

  1. Longitudinal bulk acoustic mass sensor

    DEFF Research Database (Denmark)

    Hales, Jan Harry; Teva, Jordi; Boisen, Anja;

    2009-01-01

    A polycrystalline silicon longitudinal bulk acoustic cantilever is fabricated and operated in air at 51 MHz. A mass sensitivity of 100 Hz/fg (1 fg=10(-15) g) is obtained from the preliminary experiments where a minute mass is deposited on the device by means of focused ion beam. The total noise i...

  2. Enhancement of the Bulk Photovoltaic Effect in Topological Insulators

    Science.gov (United States)

    Tan, Liang Z.; Rappe, Andrew M.

    2016-06-01

    We investigate the shift current bulk photovoltaic response of materials close to a band inversion topological phase transition. We find that the bulk photocurrent reverses direction across the band inversion transition, and that its magnitude is enhanced in the vicinity of the phase transition. These results are demonstrated with first principles density functional theory calculations of BiTeI and CsPbI3 under hydrostatic pressure, and explained with an analytical model, suggesting that this phenomenon remains robust across disparate material systems.

  3. High-aspect-ratio bulk micromachining of titanium.

    Science.gov (United States)

    Aimi, Marco F; Rao, Masa P; MacDonald, Noel C; Zuruzi, Abu Samah; Bothman, David P

    2004-02-01

    Recent process developments have permitted the highly anisotropic bulk micromachining of titanium microelectromechanical systems (MEMS). By using the metal anisotropic reactive ion etching with oxidation (MARIO) process, arbitrarily high-aspect-ratio structures with straight sidewalls and micrometre-scale features have been bulk micromachined into titanium substrates of various thicknesses, ranging from 0.5-mm sheet down to 10-microm free-standing titanium foils. Bulk micromachined structures are generally free of residual stresses and are preferred when large, rigid, flat and/or high-force actuators are desired. However, so far there has been a limited ability to select materials on the basis of specific application in bulk micromachining, primarily because of the predominance of MEMS processes dedicated to single-crystal silicon, such as silicon deep reactive ion etching. The MARIO process permits the creation of bulk titanium MEMS, which offers potential for the use of a set of material properties beyond those provided by traditional semiconductor-based MEMS. Consequently, the MARIO process enables the fabrication of novel devices that capitalize on these assets to yield enhanced functionalities that would not be possible with traditional micromechanical material systems. PMID:14743212

  4. Coulombic Fluids Bulk and Interfaces

    CERN Document Server

    Freyland, Werner

    2011-01-01

    Ionic liquids have attracted considerable interest in recent years. In this book the bulk and interfacial physico-chemical characteristics of various fluid systems dominated by Coulomb interactions are treated which includes molten salts, ionic liquids as well as metal-molten salt mixtures and expanded fluid metals. Of particular interest is the comparison of the different systems. Topics in the bulk phase concern the microscopic structure, the phase behaviour and critical phenomena, and the metal-nonmetal transition. Interfacial phenomena include wetting transitions, electrowetting, surface freezing, and the electrified ionic liquid/ electrode interface. With regard to the latter 2D and 3D electrochemical phase formation of metals and semi-conductors on the nanometer scale is described for a number of selected examples. The basic concepts and various experimental methods are introduced making the book suitable for both graduate students and researchers interested in Coulombic fluids.

  5. Materials development

    International Nuclear Information System (INIS)

    Objective of the materials program is the development of a structural material for the MSBR primary circuit which is resistant to irradiation embrittlement and intergranular attack by fission products. The bulk of the work was done on the development and study of modified Hastelloy N (Ti, Nb), including its interaction with salt and fission Te. Materials (Ta-10 percent W, Mo, graphite) are also being tested for corrosion resistance at 600 and 7000C to Bi--Li for use in fuel processing

  6. Thermal neutron diffusion parameters for media of variable bulk density

    International Nuclear Information System (INIS)

    Thermal neutron diffusion parameters (the macroscopic cross sections, and the diffusion cooling coefficients) for a given medium are dependent on the mass density. Therefore, thermal neutron experiments are influenced by the density of samples used. In the case of measurement series with bulk materials it is difficult to keep the same bulk density for all samples of the material. The classic thermal neutron pulsed experiment is considered in the paper. A method is shown to eliminate the influence of the variable bulk density on the results. A concept of the generalised decay constant and geometric buckling, and of the so-called density-removed neutron parameters, is used. Preliminary results of the Monte Carlo computer simulations of experimental series for polyethylene spherical samples of different porosity are presented. (author)

  7. 块体金属玻璃及其复合材料的压缩剪切特性和侵彻/穿甲“自锐”行为%COMPRESSIVE-SHEAR BEHAVIOR AND SELF-SHARPENING OF BULK METALLIC GLASSES AND THEIR COMPOSITE MATERIALS

    Institute of Scientific and Technical Information of China (English)

    李继承; 陈小伟

    2011-01-01

    块体金属玻璃及其复合材料以其优异的力学、物理和化学性能, 正成为国内外科技和工程领域的研究热点. 特别是金属玻璃复合材料具有高剪切敏感性和剪切 “自锐” 特性, 使其有可能成为新型穿甲弹芯材料,因而具有重要的军事意义. 本文综述了针对块体金属玻璃及其复合材料的压缩剪切变形和断裂特性及高速冲击、侵彻/穿甲过程中剪切 “自锐” 行为等方面的研究进展, 包括相关实验研究、理论分析及有限元模拟等, 最后给出未来相关工作的一些建议.%For their excellent mechanical, physical and chemic performance, bulk metallic glasses and their composite materials is now becoming an active research focus. Especially, metallic glass matrix composite may be employed as the material of kinetic enrgy penetrator for its intensive shear banding sensitivity. The present paper presents advances in the research on compressive shear deformation and fracture characteristics and self-sharpening behavior during the high-speed impact of bulk metallic glasses and their composite materials. Related experimental research, theoretical analysis and FEM simulations are reviewed, and some proposals are made for future studies.

  8. Ferroelectric properties of bulk and thin films of PMNT system

    International Nuclear Information System (INIS)

    Perovskite phase development study for bulk and thin films of PMNT 68/32 composition was carried out. B-site Columbite precursor technique was used for bulk system preparation whereas, sol-gel technique was used for thin film deposition on ITO coated glass substrates. Approximately 100% and 95% perovskite phase with grains of micron and sub-micron sizes were observed in bulk and thin films, respectively. Curie transition temperature, T c, for bulk and thin films were ∼150 deg. C and 190 deg. C, respectively. Polarization vs. electric field, P-E, hysteresis loops of PMNT 68/32 bulk and thin films showed remnant polarization, P r, ∼21.67 μC/cm2 and 1.1 μC/cm2 and coercive fields, E c, ∼3.9 and 7.7 kV/cm, respectively. Strain vs. electric field, S-E, behavior of PMNT 68/32 bulk ceramic showed piezoelectric nature of the material with a high value of maximum strain ∼1% at 19 kV/cm

  9. Free standing bulk metallic glass microcomponents: Tooling considerations

    DEFF Research Database (Denmark)

    Byrne, Cormac; Eldrup, Morten Mostgaard; Ohnuma, Masato;

    2010-01-01

    Bulk metallic glasses have enormous potential for use in small-scale devices such as MEMS and biomedical components. Thermoplastic forging of free standing components poses challenges unlike those seen when forging crystalline materials. Central to these challenges is the simultaneous advantage...

  10. Bulk metallic glass tube casting

    International Nuclear Information System (INIS)

    Research highlights: → Tubular specimens of Zr55Cu30Al10Ni5 cast in custom arc-melting furnace. → Tilt casting supplemented by suction casting. → Bulk metallic glass formed only with optimized processing parameters. → Fully amorphous tubes with 1.8 mm wall thickness and 25 mm diameter. - Abstract: Tubular bulk metallic glass specimens were produced, using a custom-built combined arc-melting tilt-casting furnace. Zr55Cu30Al10Ni5 tubes with outer diameter of 25 mm and 0.8-3 mm wall thicknesses were cast, with both tilt and suction casting to ensure mold filling. Tilt casting was found to fill one side of the tube mold first, with the rest of the tube circumference filled subsequently by suction casting. Optimized casting parameters were required to fully fill the mold and ensure glass formation. Too small melt mass and too low arc power filled the mold only partially. However, too large melt mass and higher arc power which lead to the best mold filling also lead to partial crystallization. Variations in processing parameters were explored, until a glassy ring with 1.8 mm thickness was produced. Different sections of the as-cast ring were investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and instrumented indentation to ensure amorphous microstructure. Atomic force microscopy (AFM) was used to compare the surface qualities of the first- and last-filled sections. These measurements confirmed the glassy structure of the cast ring, and that, the tilt cast tube section consistently showed better surface quality than the suction cast section. Optimized casting parameters are required to fully realize the potential of directly manufacturing complex shapes out of high-purity bulk metallic glasses by tilt casting.

  11. Bulk forming of industrial micro components in conventional metals and bulk metallic glasses

    DEFF Research Database (Denmark)

    Arentoft, Mogens; Paldan, Nikolas Aulin; Eriksen, Rasmus Solmer; Gastaldi, T.; Wert, John A.; Eldrup, Morten Mostgaard

    2007-01-01

    glasses will at elevated temperatures behave like a highly viscous liquid, which can easily form even complicated geometries in 1 step. The strengths and limitations of forming the 2 materials are analyzed for a micro 3D component in a silver alloy and an Mg-Cu-Y BMG. ©2007 American Institute of Physics......For production of micro components in large numbers, forging is an interesting and challenging process. The conventional metals like silver, steel and aluminum often require multi-step processes, but high productivity and increased strength justify the investment. As an alternative, bulk metallic...

  12. A route to transparent bulk metals

    KAUST Repository

    Schwingenschlögl, Udo

    2012-07-23

    Hypothetical compounds based on a sapphire host are investigated with respect to their structural as well as electronic features. The results are obtained by electronic structure calculations within density functional theory and the generalized gradient approximation. A quarter of the Al atoms in Al 2O 3 is replaced by a 4d transition metal M ion, with d 0 to d 9 electronic configuration. We perform structure optimizations for all the compounds and analyze the electronic states. Due to the sizeable band gap of the Al 2O 3 host, we can identify promising candidates for transparent bulk metals. We explain the mechanisms leading to this combination of materials properties. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. DEPLOYMENT OF THE BULK TRITIUM SHIPPING PACKAGE

    Energy Technology Data Exchange (ETDEWEB)

    Blanton, P.

    2013-10-10

    A new Bulk Tritium Shipping Package (BTSP) was designed by the Savannah River National Laboratory to be a replacement for a package that has been used to ship tritium in a variety of content configurations and forms since the early 1970s. The BTSP was certified by the National Nuclear Safety Administration in 2011 for shipments of up to 150 grams of Tritium. Thirty packages were procured and are being delivered to various DOE sites for operational use. This paper summarizes the design features of the BTSP, as well as associated engineered material improvements. Fabrication challenges encountered during production are discussed as well as fielding requirements. Current approved tritium content forms (gas and tritium hydrides), are reviewed, as well as, a new content, tritium contaminated water on molecular sieves. Issues associated with gas generation will also be discussed.

  14. Gold based bulk metallic glass

    OpenAIRE

    Schroers, Jan; Lohwongwatana, Boonrat; Johnson, William L.; Peker, Atakan

    2005-01-01

    Gold-based bulk metallic glass alloys based on Au-Cu-Si are introduced. The alloys exhibit a gold content comparable to 18-karat gold. They show very low liquidus temperature, large supercooled liquid region, and good processibility. The maximum casting thickness exceeds 5 mm in the best glassformer. Au49Ag5.5Pd2.3Cu26.9Si16.3 has a liquidus temperature of 644 K, a glass transition temperature of 401 K, and a supercooled liquid region of 58 K. The Vickers hardness of the alloys in this system...

  15. Organic bulk heterojunction photovoltaic structures: design, morphology and properties

    International Nuclear Information System (INIS)

    Main approaches to the design of organic bulk heterojunction photovoltaic structures are generalized and systematized. Novel photovoltaic materials based on fullerenes, organic dyes and related compounds, graphene, conjugated polymers and dendrimers are considered. The emphasis is placed on correlations between the chemical structure and properties of materials. The effect of morphology of the photoactive layer on the photovoltaic properties of devices is analyzed. Main methods of optimization of the photovoltaic properties are outlined. The bibliography includes 338 references

  16. Faraday cage angled-etching of nanostructures in bulk dielectrics

    OpenAIRE

    Latawiec, Pawel; Burek, Michael J.; Sohn, Young-Ik; Lončar, Marko

    2016-01-01

    For many emerging optoelectronic materials, heteroepitaxial growth techniques do not offer the same high material quality afforded by bulk, single-crystal growth. However, the need for optical, electrical, or mechanical isolation at the nanoscale level often necessitates the use of a dissimilar substrate, upon which the active device layer stands. Faraday cage angled-etching (FCAE) obviates the need for these planar, thin-film technologies by enabling in-situ device release and isolation thro...

  17. Bulk dynamics for interfacial growth models

    OpenAIRE

    López, Cristóbal; Santos, Fernando; Garrido, P. L.

    2000-01-01

    We study the influence of the bulk dynamics of a growing cluster of particles on the properties of its interface. First, we define a general bulk growth model by means of a continuum Master equation for the evolution of the bulk density field. This general model just considers an arbitrary addition of particles (though it can be easily generalized to consider subtraction) with no other physical restriction. The corresponding Langevin equation for this bulk density field is derived where the i...

  18. Photoelectron spectroscopy bulk and surface electronic structures

    CERN Document Server

    Suga, Shigemasa

    2014-01-01

    Photoelectron spectroscopy is now becoming more and more required to investigate electronic structures of various solid materials in the bulk, on surfaces as well as at buried interfaces. The energy resolution was much improved in the last decade down to 1 meV in the low photon energy region. Now this technique is available from a few eV up to 10 keV by use of lasers, electron cyclotron resonance lamps in addition to synchrotron radiation and X-ray tubes. High resolution angle resolved photoelectron spectroscopy (ARPES) is now widely applied to band mapping of materials. It attracts a wide attention from both fundamental science and material engineering. Studies of the dynamics of excited states are feasible by time of flight spectroscopy with fully utilizing the pulse structures of synchrotron radiation as well as lasers including the free electron lasers (FEL). Spin resolved studies also made dramatic progress by using higher efficiency spin detectors and two dimensional spin detectors. Polarization depend...

  19. Growth Techniques for Bulk ZnO and Related Compounds

    OpenAIRE

    Klimm, Detlef; Schulz, Detlev; Ganschow, Steffen; Galazka, Zbigniew; Uecker, Reinhard

    2011-01-01

    ZnO bulk crystals can be grown by several methods. 1) From the gas phase, usually by chemical vapor transport. Such CVT crystals may have high chemical purity, as the growth is performed without contact to foreign material. The crystallographic quality is often very high (free growth). 2) From melt fluxes such as alkaline hydroxides or other oxides (MoO3, V2O5, P2O5, PbO) and salts (PbCl2, PbF2). Melt fluxes offer the possibility to grow bulk ZnO under mild conditions (

  20. Optimization of PGNAA instrument design for bulk coal analysis

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, C.; Salgado, J.; Carvalho, F.G. (National Laboratory for Industrial Technology and Engineering, Sacavem (Portugal). Physics Dept.)

    1993-06-01

    A simulation study of a PGNAA system for bulk coal analysis has been carried out using the MCNP code to investigate the dependence of the system's performance on design parameters for different coal compositions and bulk densities. Calculations were performed for simulated arrangements using a naked point [sup 252]Cf source and the source surrounded by a sphere of moderating material. Results for different sample sizes and different radii of the moderating sphere are reported. The system's optimization based upon the proper choice of sample size and amount of external thermalization is discussed. 3 refs., 18 figs., 1 tab.

  1. Homogenizer of cement mix with liquid and bulk radioactive wastes

    International Nuclear Information System (INIS)

    The lid of the homogenizer vessel with a stirrer and with bulk and liquid inlets is firmly attached to the homogenizer frame. The mixing vessel is screwed onto the lid and is connected to the frame with two moving arms. This allows to separate the mixing vessel from the lid without having to disconnect the supplies of bulk and liquid materials. The vessel is attached to swing arms pivoted in joints, which allows servicing, turning and tipping the vessel, thereby facilitating its emptying. This facilitates cleaning and reduces the maintenance time, thus increasing the safety of personnel. (J.B.). 2 figs

  2. Synthesis and characterization of a bulk amorphous alloy

    International Nuclear Information System (INIS)

    The production and characterization of bulk metallic glasses have been an area of intense focus in materials research for many years because of their superior mechanical properties over their crystalline counterparts. A bulk metallic glass Zr/sub 55/Cu/sub 30/Al/sub 10/Ni/sub 5/ has been synthesized by copper mold casting and characterized by differential scanning calorimetry and x-ray diffraction. Crystallization behavior of the alloy is discussed. Composite of amorphous glass was produced by adding SiC and hardness and tensile strength have been measured. (author)

  3. Majorana boundary modes in Josephson junctions arrays with gapless bulk excitations

    OpenAIRE

    Pino, M.; A.M. Tsvelik; Ioffe, L. B.

    2015-01-01

    The search for Majorana bound states in solid-state physics has been limited to materials which display a gap in their bulk spectrum. We show that such unpaired states appear in certain quasi-one-dimensional Josephson junctions arrays with gapless bulk excitations. The bulk modes mediate a coupling between Majorana bound states via the Ruderman-Kittel-Yosida-Kasuya mechanism. As a consequence, the lowest energy doublet acquires a finite energy difference. For realistic set of parameters this ...

  4. Magnetic levitation force between a superconducting bulk magnet and a permanent magnet

    OpenAIRE

    J. J. Wang; C. Y. He; Meng, L F; C Li; Han, R. S.; Gao, Z X

    2002-01-01

    The current density in a disk-shaped superconducting bulk magnet and the magnetic levitation force exerted on the superconducting bulk magnet by a cylindrical permanent magnet are calculated from first principles. The effect of the superconducting parameters of the superconducting bulk is taken into account by assuming the voltage-current law and the material law. The magnetic levitation force is dominated by the remnant current density, which is induced by switching off the applied magnetizi...

  5. 75 FR 64585 - Bulk Solid Hazardous Materials: Harmonization With the International Maritime Solid Bulk Cargoes...

    Science.gov (United States)

    2010-10-19

    ... rulemaking (docket number: CGD 87-069) that the Coast Guard closed in 1995. The 1989 advance NPRM (54 FR... Homeland Security DRI Direct Reduced Iron FR Federal Register IMO International Maritime Organization IMSBC... Federal Register (75 FR 34574). We also published a correction on June 18, 2010, addressing...

  6. Low-Temperature Cationic Rearrangement in a Bulk Metal Oxide.

    Science.gov (United States)

    Li, Man-Rong; Retuerto, Maria; Stephens, Peter W; Croft, Mark; Sheptyakov, Denis; Pomjakushin, Vladimir; Deng, Zheng; Akamatsu, Hirofumi; Gopalan, Venkatraman; Sánchez-Benítez, Javier; Saouma, Felix O; Jang, Joon I; Walker, David; Greenblatt, Martha

    2016-08-16

    Cationic rearrangement is a compelling strategy for producing desirable physical properties by atomic-scale manipulation. However, activating ionic diffusion typically requires high temperature, and in some cases also high pressure in bulk oxide materials. Herein, we present the cationic rearrangement in bulk Mn2 FeMoO6 at unparalleled low temperatures of 150-300 (o) C. The irreversible ionic motion at ambient pressure, as evidenced by real-time powder synchrotron X-ray and neutron diffraction, and second harmonic generation, leads to a transition from a Ni3 TeO6 -type to an ordered-ilmenite structure, and dramatic changes of the electrical and magnetic properties. This work demonstrates a remarkable cationic rearrangement, with corresponding large changes in the physical properties in a bulk oxide at unprecedented low temperatures. PMID:27203790

  7. Gold based bulk metallic glass

    Science.gov (United States)

    Schroers, Jan; Lohwongwatana, Boonrat; Johnson, William L.; Peker, Atakan

    2005-08-01

    Gold-based bulk metallic glass alloys based on Au-Cu-Si are introduced. The alloys exhibit a gold content comparable to 18-karat gold. They show very low liquidus temperature, large supercooled liquid region, and good processibility. The maximum casting thickness exceeds 5mm in the best glassformer. Au49Ag5.5Pd2.3Cu26.9Si16.3 has a liquidus temperature of 644K, a glass transition temperature of 401K, and a supercooled liquid region of 58K. The Vickers hardness of the alloys in this system is ˜350Hv, twice that of conventional 18-karat crystalline gold alloys. This combination of properties makes the alloys attractive for many applications including electronic, medical, dental, surface coating, and jewelry.

  8. Gold based bulk metallic glass

    International Nuclear Information System (INIS)

    Gold-based bulk metallic glass alloys based on Au-Cu-Si are introduced. The alloys exhibit a gold content comparable to 18-karat gold. They show very low liquidus temperature, large supercooled liquid region, and good processibility. The maximum casting thickness exceeds 5 mm in the best glassformer. Au49Ag5.5Pd2.3Cu26.9Si16.3 has a liquidus temperature of 644 K, a glass transition temperature of 401 K, and a supercooled liquid region of 58 K. The Vickers hardness of the alloys in this system is ∼350 Hv, twice that of conventional 18-karat crystalline gold alloys. This combination of properties makes the alloys attractive for many applications including electronic, medical, dental, surface coating, and jewelry

  9. Bulk analysis using nuclear techniques

    International Nuclear Information System (INIS)

    Bulk analysis techniques developed for the mining industry are reviewed. Using penetrating neutron and #betta#-radiations, measurements are obtained directly from a large volume of sample (3-30 kg) #betta#-techniques were used to determine the grade of iron ore and to detect shale on conveyor belts. Thermal neutron irradiation was developed for the simultaneous determination of iron and aluminium in iron ore on a conveyor belt. Thermal-neutron activation analysis includes the determination of alumina in bauxite, and manganese and alumina in manganese ore. Fast neutron activation analysis is used to determine silicon in iron ores, and alumina and silica in bauxite. Fast and thermal neutron activation has been used to determine the soil in shredded sugar cane. (U.K.)

  10. Isotopic signatures by bulk analyses

    International Nuclear Information System (INIS)

    Los Alamos National Laboratory has developed a series of measurement techniques for identification of nuclear signatures by analyzing bulk samples. Two specific applications for isotopic fingerprinting to identify the origin of anthropogenic radioactivity in bulk samples are presented. The first example is the analyses of environmental samples collected in the US Arctic to determine the impact of dumping of radionuclides in this polar region. Analyses of sediment and biota samples indicate that for the areas sampled the anthropogenic radionuclide content of sediments was predominantly the result of the deposition of global fallout. The anthropogenic radionuclide concentrations in fish, birds and mammals were very low. It can be surmised that marine food chains are presently not significantly affected. The second example is isotopic fingerprinting of water and sediment samples from the Rocky Flats Facility (RFP). The largest source of anthropogenic radioactivity presently affecting surface-waters at RFP is the sediments that are currently residing in the holding ponds. One gram of sediment from a holding pond contains approximately 50 times more plutonium than 1 liter of water from the pond. Essentially 100% of the uranium in Ponds A-1 and A-2 originated as depleted uranium. The largest source of radioactivity in the terminal Ponds A-4, B-5 and C-2 was naturally occurring uranium and its decay product radium. The uranium concentrations in the waters collected from the terminal ponds contained 0.05% or less of the interim standard calculated derived concentration guide for uranium in waters available to the public. All of the radioactivity observed in soil, sediment and water samples collected at RFP was naturally occurring, the result of processes at RFP or the result of global fallout. No extraneous anthropogenic alpha, beta or gamma activities were detected. The plutonium concentrations in Pond C-2 appear to vary seasonally

  11. Guidelines for Measuring Bulk Density of Soil

    International Nuclear Information System (INIS)

    Bulk density is defined as the dry weight of soil per unit volume of undisturbed soil. • Bulk density can be used to give an indication of the porosity and structure of the soil influencing O2 and H2O movement in the soil. • Soils with a bulk density higher than 1.6 g/cm3 may restrict root development. • Bulk density is also a measurement of the degree of compaction of the soil. • Bulk density increases with compaction and tends to increase with soil depth. • Sandy soils tend to have higher bulk density (1.4-1.5 g/cm3) than clay soils (1.2-1/3g/cm3). The measurement of soil bulk density is carried out by collecting undisturbed soil samples through inserting metal rings (with a known volume) into the soil, and determining the weight of the collected soil after drying

  12. High-pressure X-ray diffraction study of bulk- and nanocrystalline GaN

    DEFF Research Database (Denmark)

    Jorgensen, J.E.; Jakobsen, J.M.; Jiang, Jianzhong;

    2003-01-01

    Bulk- and nanocrystalline GaN have been studied by high-pressure energy-dispersive X-ray diffraction. Pressure-induced structural phase transitions from the wurtzite to the NaCl phase were observed in both materials. The transition pressure was found to be 40 GPa for the bulk-crystalline GaN, while...

  13. Studies of bulk heterojunction solar cells

    Science.gov (United States)

    Cossel, Raquel; McIntyre, Max; Tzolov, Marian

    We are studying bulk heterojunction solar cells that were fabricated using a mixture of PCPDTBT and PCBM­C60. The impedance data of the cells in dark responded like a simple RC circuit. The value of the dielectric constant derived from these results is consistent with the values reported in the literature for these materials. We are showing that the parallel resistance in the equivalent circuit of linear lump elements can be interpreted using the DC current­voltage measurements. The impedance spectra under light illumination indicated the existence of additional polarization. This extra feature can be described by a model that includes a series RC circuit in parallel with the equivalent circuit for a device in dark. The physical interpretation of the additional polarization is based on photo­generated charges getting trapped in wells, which have a characteristic relaxation time corresponding to the observed break frequency in the impedance spectra. We have studied the influence of the anode and cathode interface on this phenomena, either by using different interface materials, or by depositing the metal electrode while the substate is heated.

  14. Leachables evaluation for bulk drug substance.

    Science.gov (United States)

    Tsui, Victor; Somma, Maria S; Zitzner, Linda A

    2009-01-01

    This study describes a comprehensive analytical approach for evaluating potential leachables from product-contacting material surfaces in the manufacture of bulk drug substance (BDS) for use in parenteral products. A qualitative step-by-step evaluation of the process stream for the production, purification, and storage of the BDS was performed. The product-contact equipment surfaces were then grouped based on their materials of construction and prioritized according to the potential risk of contributing leachables to the BDS. Based on this evaluation, 13 potential leachable species were identified and classified either as volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), anions, cations, or trace metals. The BDS was first screened for the presence of VOCs, SVOCs, anions, cations, and trace metals using analytical methods that were qualified for their application with the BDS. Thirteen potential leachables were then spiked in the BDS and in the water for injection for spike-recovery studies. The analysis of the BDS for potential leachables showed that the potential impurities were not present in the BDS except for a trace amount of silicon, and that the residual solvent concentrations were lower than the recommended limits established by the International Committee on Harmonisation. The spike-recovery studies confirmed that the analytical methods could effectively determine the leachable compounds in the BDS. Moreover, the 13 contaminants did not form a complex with the protein in the BDS and did not represent a potential risk to the BDS's safety and stability. PMID:19634355

  15. Permanent magnet with MgB{sub 2} bulk superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Akiyasu, E-mail: yamamoto@appchem.t.u-tokyo.ac.jp [The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); JST-PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Ishihara, Atsushi; Tomita, Masaru [Railway Technical Research Institute, 2-8-38 Hikari, Kokubunji, Tokyo 185-8540 (Japan); Kishio, Kohji [The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan)

    2014-07-21

    Superconductors with persistent zero-resistance currents serve as permanent magnets for high-field applications requiring a strong and stable magnetic field, such as magnetic resonance imaging. The recent global helium shortage has quickened research into high-temperature superconductors (HTSs)—materials that can be used without conventional liquid-helium cooling to 4.2 K. Herein, we demonstrate that 40-K-class metallic HTS magnesium diboride (MgB{sub 2}) makes an excellent permanent bulk magnet, maintaining 3 T at 20 K for 1 week with an extremely high stability (<0.1 ppm/h). The magnetic field trapped in this magnet is uniformly distributed, as for single-crystalline neodymium-iron-boron. Magnetic hysteresis loop of the MgB{sub 2} permanent bulk magnet was determined. Because MgB{sub 2} is a simple-binary-line compound that does not contain rare-earth metals, polycrystalline bulk material can be industrially fabricated at low cost and with high yield to serve as strong magnets that are compatible with conventional compact cryocoolers, making MgB{sub 2} bulks promising for the next generation of Tesla-class permanent-magnet applications.

  16. Relative entropy equals bulk relative entropy

    CERN Document Server

    Jafferis, Daniel L; Maldacena, Juan; Suh, S Josephine

    2015-01-01

    We consider the gravity dual of the modular Hamiltonian associated to a general subregion of a boundary theory. We use it to argue that the relative entropy of nearby states is given by the relative entropy in the bulk, to leading order in the bulk gravitational coupling. We also argue that the boundary modular flow is dual to the bulk modular flow in the entanglement wedge, with implications for entanglement wedge reconstruction.

  17. Coupling brane fields to bulk supergravity

    International Nuclear Information System (INIS)

    In this note we present a simple, general prescription for coupling brane localized fields to bulk supergravity. We illustrate the procedure by considering 6D N=2 bulk supergravity on a 2D orbifold, with brane fields localized at the fixed points. The resulting action enjoys the full 6D N=2 symmetries in the bulk, and those of 4D N=1 supergravity at the brane positions. (orig.)

  18. Coupling brane fields to bulk supergravity

    Energy Technology Data Exchange (ETDEWEB)

    Parameswaran, Susha L. [Uppsala Univ. (Sweden). Theoretical Physics; Schmidt, Jonas [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2010-12-15

    In this note we present a simple, general prescription for coupling brane localized fields to bulk supergravity. We illustrate the procedure by considering 6D N=2 bulk supergravity on a 2D orbifold, with brane fields localized at the fixed points. The resulting action enjoys the full 6D N=2 symmetries in the bulk, and those of 4D N=1 supergravity at the brane positions. (orig.)

  19. Business Pattern Innovation in Bulk Production Material Circulation Enterprises under the Trend of Disintermediation in China——The Business Practice of Zhejiang Material Industry Group%流通脱媒趋势下生产资料流通企业商业模式创新——来自浙江物产集团的商业实践

    Institute of Scientific and Technical Information of China (English)

    刘庆岩

    2016-01-01

    In recent years,with the rise of ICT and the increasing pressure brought by higher upstream cost and inefficient downstream demand,to shorten circulation channel,reduce circulation links,reduce circulation cost,or extent to the field of service to pursue"the third profit source",manufacturing enterprises increasingly strengthen their power of control on channels, and directly establish the strategic alliance with the absence of intermediaries. To some extent,these measures will shrink the living space of traditional circulation enterprises and lead to the phenomenon of disintermediation. And the enterprises will transform from being comprehensive to being specialized,from independently owning the resources to sharing that,and from being rival to each other to cooperating with each other. To better cope with the trend of disintermediation,ZJMI Group integrates the role of wholesaler,logistic service provider,transaction interface,market explorer,and modular integration service provider and embeds the link of supply chain to successfully expand its business scope,form the customer-demand-oriented supply chain integrated service pattern,and establish its own competitiveness. The experience of ZJMI cannot only be learn by other bulk production material enterprises,but also provide other traditional circulation enterprises with important implications. To cope with impact brought by new technology,at the stage of transferring from old balance to new balance,circulation enterprises should reconsider their functional positioning,take the value of upstream and downstream customers as the target,fully give play to the role of information,logistic,and management technological fruits,make innovation in business pattern,rebuild the competitiveness,effectively reduce agent cost,promote the return of intermediaries,and promote the rapid development of service outsourcing industry.%近年来,随着网络通信技术的兴起,受上游成本高企与下游需求不足双重压力

  20. Pulsed-field magnetization of a bulk superconductor with small holes

    International Nuclear Information System (INIS)

    Highlights: ► We propose the bulk material with small holes which makes the role of a flux path. ► The flux is supplied to the bulk reducing heat generation by the artificial path. ► The validity is investigated by the fundamental test of a single pulse application. ► It was confirmed that the magnetic flux penetrated even with a low applied field. ► Flux flow was small in a high applied field compared with a usual hole-less bulk. -- Abstract: Recent enlargement of the size and the performance enhancement of bulk superconductor lead to the difficulty of magnetic flux trapping by a pulsed-field magnetization. This paper proposes the bulk material with small holes which makes the role of an artificial magnetic flux path to supply the flux in the bulk. The fundamental experiment of applying a single pulsed-field with varying amplitudes was carried out using a ∅60 mm × 20 mm GdBa2Cu3O7−x bulk material with four ∅2 mm holes filled up with solder. Compared with a usual hole-less bulk, the total magnetic flux and the maximum trapped flux density were greatly increased in a low applied field. Moreover, those large reduction caused by flux flow was suppressed in a high applied field

  1. Design of solar drying-plant for bulk material drying

    International Nuclear Information System (INIS)

    Cooling process of big superconducting magnets from temperature of surrounding to the critical temperature is a very complicated process from economical as well as from technical view. In case when cryostat containing experimental device overcool itself from normal temperature directly with liquid helium the consumption would be considerably higher than in case that we use liquid nitrogen for first overcool. Thus whole process of overcooling would be considerably nonprofitable. The article describes experience with overflowing of superconducting magnets installed in laboratory at the Technical University in Kosice, where the research project for the electric energy in the magnetic field storage takes place. (authors)

  2. TAKRAF belt conveyors - effective means of transport for bulk materials

    Energy Technology Data Exchange (ETDEWEB)

    Peterman, L.

    1988-11-01

    Presents belt conveyor types produced by TAKRAF, especially those intended for use at surface mines. The FAM works (Transport Equipment) produces belt conveyors 800-1,400 mm wide, with 2.09-5.24 m/s belt velocity, 460-3,750 m/sup 3//h capacity, max. feed distance 2,500 m and (1-5)x55 kW drive power. The drive stations are based on pontoons or caterpillar vehicles while the end-stations are based on pontoons. Charging hoppers have autonomic drives and are mobile on rail. The described conveyors can also be used in power plants. The FAM works produces 650-800 mm wide conveyors for thermal electric power stations. The conveyors are equipped with metal detectors and metal separators.

  3. Error analysis in the taking of samples from bulk material

    International Nuclear Information System (INIS)

    In the goods quality testing carried out on a sampling basis, errors must be accounted for regarding conclusions on the population. Here various methods for the error source analysis with several multistep sampling procedures are given and compared with concrete examples. (orig.)

  4. Bulk scalar field in DGP braneworld cosmology

    CERN Document Server

    Ansari, Rizwan ul Haq

    2007-01-01

    We investigated the effects of bulk scalar field in the braneworld cosmological scenario. The Friedmann equations and acceleration condition in presence of the bulk scalar field for a zero tension brane and cosmological constant are studied. In DGP model the effective Einstein equation on the brane is obtained with bulk scalar field. The rescaled bulk scalar field on the brane in the DGP model behaves as an effective four dimensional field, thus standard type cosmology is recovered. In present study of the DGP model, the late-time accelerating phase of the universe can be explained .

  5. Bulk-edge correspondence for topological photonic continua

    CERN Document Server

    Silveirinha, Mario G

    2016-01-01

    Here, building on our previous work [Phys. Rev. B, 92, 125153, (2015)], it is shown that the propagation of unidirectional gapless edge states at an interface of two topologically distinct electromagnetic continua with a well-behaved asymptotic electromagnetic response is rigorously predicted by the bulk-edge correspondence principle. We work out detailed examples demonstrating that when the spatial-cut off of the nonreciprocal part of the material response is considered self-consistently in the solution of the relevant electromagnetic problem, the number of unidirectional gapless edge modes is identical to the difference of the Chern numbers of the bulk materials. Furthermore, it is shown how the role of the spatial cut-off can be imitated in realistic systems using a tiny air gap with a specific thickness. This theory provides a practical roadmap for the application of topological concepts to photonic platforms formed by nonreciprocal electromagnetic continua.

  6. Properties of Bulk Sintered Silver As a Function of Porosity

    Energy Technology Data Exchange (ETDEWEB)

    Wereszczak, Andrew A [ORNL; Vuono, Daniel J [ORNL; Wang, Hsin [ORNL; Ferber, Mattison K [ORNL; Liang, Zhenxian [ORNL

    2012-06-01

    This report summarizes a study where various properties of bulk-sintered silver were investigated over a range of porosity. This work was conducted within the National Transportation Research Center's Power Device Packaging project that is part of the DOE Vehicle Technologies Advanced Power Electronics and Electric Motors Program. Sintered silver, as an interconnect material in power electronics, inherently has porosity in its produced structure because of the way it is made. Therefore, interest existed in this study to examine if that porosity affected electrical properties, thermal properties, and mechanical properties because any dependencies could affect the intended function (e.g., thermal transfer, mechanical stress relief, etc.) or reliability of that interconnect layer and alter how its performance is modeled. Disks of bulk-sintered silver were fabricated using different starting silver pastes and different sintering conditions to promote different amounts of porosity. Test coupons were harvested out of the disks to measure electrical resistivity and electrical conductivity, thermal conductivity, coefficient of thermal expansion, elastic modulus, Poisson's ratio, and yield stress. The authors fully recognize that the microstructure of processed bulk silver coupons may indeed not be identical to the microstructure produced in thin (20-50 microns) layers of sintered silver. However, measuring these same properties with such a thin actual structure is very difficult, requires very specialized specimen preparation and unique testing instrumentation, is expensive, and has experimental shortfalls of its own, so the authors concluded that the herein measured responses using processed bulk sintered silver coupons would be sufficient to determine acceptable values of those properties. Almost all the investigated properties of bulk sintered silver changed with porosity content within a range of 3-38% porosity. Electrical resistivity, electrical conductivity

  7. Evolution of bulk strain solitons in cylindrical inhomogeneous shells

    Energy Technology Data Exchange (ETDEWEB)

    Shvartz, A., E-mail: andrew.shvartz@mail.ioffe.ru; Samsonov, A.; Dreiden, G.; Semenova, I. [Ioffe Institute, 26 Politekhnicheskaya, St Petersburg 194021 (Russian Federation)

    2015-10-28

    Bulk strain solitary waves in nonlinearly elastic thin-walled cylindrical shells with variable geometrical and physical parameters are studied, and equation for the longitudinal strain component with the variable coefficients is derived. A conservative finite difference scheme is proposed, and the results of numerical simulation of the strain soliton evolution in a shell with the abrupt variations of cross section and physical properties of the material are presented.

  8. Iron-based bulk metallic glasses - Optimization of casting

    Czech Academy of Sciences Publication Activity Database

    Stloukal, Ivo; Král, Lubomír; Čermák, Jiří

    Ostrava: Tanger s. r. o, 2009, s. 481-487. ISBN 978-80-87294-04-8. [METAL 2009. Mezinárodní konference metalurgie a materiálů /18./. Hradec nad Moravicí (CZ), 19.05.2009-21.05.2009] R&D Projects: GA ČR GA106/08/1241 Institutional research plan: CEZ:AV0Z20410507 Keywords : bulk metallic glasses * iron-based alloy * casting optimization Subject RIV: BJ - Thermodynamics

  9. Surface and Bulk Nanostructuring of Polymers Using Ionizing Radiation

    International Nuclear Information System (INIS)

    Ionizing radiation has long been known tobe a powerful tool in modifying and controlled the properties, forms and eventually end-uses of polymeric materials for a variety of applications. Industrial applications are full of successful examples of macro scale, bulk property modifications by radiation. Extremely short wavelength of ionizing radiation however, makes it an important and useful tool in creating very small size structures in polymers

  10. Fabrication of bulk metallic glasses by centrifugal casting method

    OpenAIRE

    R. Nowosielski; R. Babilas

    2007-01-01

    Purpose: The aim of the present work is characterization of the centrifugal casting method, apparatus andproduced amorphous materials, which are also known as bulk metallic glassesDesign/methodology/approach: The studied centrifugal casting system consists of two main parts: castingapparatus and injection system of molten alloy. The described centrifugal casting method was presented bypreparing a casting apparatus “CentriCast – 5”. The apparatus includes a cylindrical copper mold, which isrot...

  11. Characterization of adhesively bonded joints using bulk adhesive properties

    OpenAIRE

    Kon, Haruhiko

    1991-01-01

    Though using bulk adhesive properties to predict adhesively bonded joint response has yet to be proven infallible, based upon the success of previous works, this effort attempts to shed some light on the stresses present in a typical automotive bonded joint. Adhesive material properties obtained in previous works were used in a finite element analysis of a simulated automotive joint to predict the stresses in that joint. The automotive joint analyzed was a simplified repr...

  12. Standard practice for bulk sampling of liquid uranium hexafluoride

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2001-01-01

    1.1 This practice covers methods for withdrawing representative samples of liquid uranium hexafluoride (UF6) from bulk quantities of the material. Such samples are used for determining compliance with the applicable commercial specification, for example Specification C787 and Specification C996. 1.2 It is assumed that the bulk liquid UF6 being sampled comprises a single quality and quantity of material. This practice does not address any special additional arrangements that might be required for taking proportional or composite samples, or when the sampled bulk material is being added to UF6 residues already in a container (“heels recycle”). 1.3 The number of samples to be taken, their nominal sample weight, and their disposition shall be agreed upon between the parties. 1.4 The scope of this practice does not include provisions for preventing criticality incidents. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of th...

  13. Electric field dependence of the electron mobility in bulk wurtzite ZnO

    Indian Academy of Sciences (India)

    K Alfaramawi

    2014-12-01

    The electric field dependence of the electron mobility in bulk wurtzite zinc oxide (ZnO) material is studied. The low-field electron mobility is calculated as a function of doping concentration and lattice temperature. The results show that above nearly 50 K the electrical conduction is governed by activation through the bulk material and the conduction is then influenced by both lattice and impurity scattering mechanisms. The high-field characteristics are also considered. The transition between the low-field and high-field regions is specified. The negative differential mobility for bulk ZnO at room temperature is observed at electric fields above 280 kV/cm.

  14. The effect of cesium vapour on the bulk conductivity of plasma. Sprayed alumina

    International Nuclear Information System (INIS)

    We have shown that Cs vapour is able to easily penetrate the bulk of plasma-sprayed alumina, leading to large increases in the bulk conductivity of the material. We have determined the temperature and pressure dependencies over a significant and technologically relevant range. In contrast to the surface conductivity we have found that the bulk conductivity exhibits a significant dependence on Cs pressure, varying approximately linearly with PCs. We believe that this effect represents a potentially significant degradation mechanism for single cell thermionic fuel elements which utilize this material. (author)

  15. 27 CFR 20.191 - Bulk articles.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Bulk articles. 20.191... Users of Specially Denatured Spirits Operations by Users § 20.191 Bulk articles. Users who convey articles in containers exceeding one gallon may provide the recipient with a photocopy of subpart G of...

  16. Bulk equations of motion from CFT correlators

    CERN Document Server

    Kabat, Daniel

    2015-01-01

    To O(1/N) we derive, purely from CFT data, the bulk equations of motion for interacting scalar fields and for scalars coupled to gauge fields and gravity. We first uplift CFT operators to mimic local AdS fields by imposing bulk microcausality. This requires adding an infinite tower of smeared higher-dimension double-trace operators to the CFT definition of a bulk field, with coefficients that we explicitly compute. By summing the contribution of the higher-dimension operators we derive the equations of motion satisfied by these uplifted CFT operators and show that we precisely recover the expected bulk equations of motion. We exhibit the freedom in the CFT construction which corresponds to bulk field redefinitions.

  17. Advanced tensile testing methods for bulk superconductors at cryogenic temperatures

    International Nuclear Information System (INIS)

    Tensile tests of bulk high Tc superconductors at room temperature have been generally performed by gluing the bulk specimens to Al-alloy rods. Because of the difference in the coefficient of thermal expansion, thermal stresses were induced at cryogenic temperatures especially near the interface between the specimen and the rods. In this study, tensile testing methods with minimized effect of the thermal stress were tried by using specimens cut from Dy-Ba-Cu-O superconductors. These were: (1) The rod material of Al-alloy was replaced with Ti-alloy, which has the coefficient close to the bulk. (2) The interlayer made of the identical bulk superconductor was inserted between the specimen and the Ti-alloy rod. The nominal tensile strength at the liquid nitrogen temperature (LNT) of the specimen glued to the Ti-alloy rods was significantly higher than that glued to the Al-alloy rods. The application of the interlayers increased the strength significantly. The FEM analysis showed that the thermal tensile stress component in the direction of loading axis within the specimen at LNT is markedly reduced by the method (1) and substantially eliminated in the method (2)

  18. Stability analysis of active acoustic metamaterial with programmable bulk modulus

    International Nuclear Information System (INIS)

    Acoustic metamaterials (AMMs) have been considered as an effective means of controlling the propagation of acoustical wave energy through metamaterials. However, most of the currently exerted efforts are focused on studying passive metamaterials with fixed material properties. In this paper, the emphasis is placed on the development of a new class of one-dimensional acoustic metamaterials with effective bulk moduli that are programmed to vary according to any prescribed pattern along the volume of the metamaterial. Acoustic cavities coupled with either actively controlled Helmholtz or flush-mounted resonators are introduced to develop two possible configurations for obtaining active AMMs (AAMMs) with programmable bulk modulus capabilities. The resonators are provided with piezoelectric boundaries to enable control of the overall bulk modulus of the acoustic cavity through direct acoustic pressure feedback. Theoretical analyses of these two configurations of AAMMs are presented using the lumped-parameter modeling approach. The presented analyses are utilized to study the stability characteristics of the two configurations in an attempt to define their stable regions of operation. Numerical examples are presented to demonstrate the performance characteristics of the proposed AAMM configurations and their potential for generating prescribed spatial and spectral patterns of bulk modulus variation

  19. Lunar Materials Handling System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Lunar Materials Handling System (LMHS) is a method for transfer of bulk materials and products into and out of process equipment in support of lunar and Mars in...

  20. Negative Refractive Index in Left-Handed Materials

    International Nuclear Information System (INIS)

    The real part of the refractive index n(ω) of a nearly transparent and passive medium is usually taken to have only positive values. Through an analysis of a current source radiating into a 1D ''left-handed'' material (LHM) -- where the permittivity and permeability are simultaneously less than zero -- we determine the analytic structure of n(ω) , demonstrating frequency regions where the sign of Re[n(ω)] must, in fact, be negative. The regime of negative index, made relevant by a recent demonstration of an effective LHM, leads to unusual electromagnetic wave propagation and merits further exploration

  1. Bulk Viscosity in Holographic Lifshitz Hydrodynamics

    CERN Document Server

    Hoyos, Carlos; Oz, Yaron

    2013-01-01

    We compute the bulk viscosity in holographic models dual to theories with Lifshitz scaling and/or hyperscaling violation, using a generalization of the bulk viscosity formula derived in arXiv:1103.1657 from the null focusing equation. We find that only a class of models with massive vector fields are truly Lifshitz scale invariant, and have a vanishing bulk viscosity. For other holographic models with scalars and/or massless vector fields we find a universal formula in terms of the dynamical exponent and the hyperscaling violation exponent.

  2. Bulk viscosity in holographic Lifshitz hydrodynamics

    OpenAIRE

    Carlos Hoyos; Bom Soo Kim; Yaron Oz

    2014-01-01

    We compute the bulk viscosity in holographic models dual to theories with Lifshitz scaling and/or hyperscaling violation, using a generalization of the bulk viscosity formula derived in arXiv:1103.1657 from the null focusing equation. We find that only a class of models with massive vector fields are truly Lifshitz scale invariant, and have a vanishing bulk viscosity. For other holographic models with scalars and/or massless vector fields we find a universal formula in terms of the dynamical ...

  3. Bulk viscosity in holographic Lifshitz hydrodynamics

    International Nuclear Information System (INIS)

    We compute the bulk viscosity in holographic models dual to theories with Lifshitz scaling and/or hyperscaling violation, using a generalization of the bulk viscosity formula derived in arXiv:1103.1657 from the null focusing equation. We find that only a class of models with massive vector fields are truly Lifshitz scale invariant, and have a vanishing bulk viscosity. For other holographic models with scalars and/or massless vector fields we find a universal formula in terms of the dynamical exponent and the hyperscaling violation exponent

  4. Bulk viscosity of hot and dense hadrons

    International Nuclear Information System (INIS)

    The bulk viscosity of hot and dense hadrons has been estimated within the framework of hadronic resonance gas model. We observe that the bulk viscosity to entropy ratio increases faster with temperature for higher μB. The magnitude of ζ is more at high μB. This results will have crucial importance for fire-ball produced at low energy nuclear collisions (FAIR, NICA). We note that the bulk to shear viscosity ratio remains above the bound set by AdS/CFT

  5. Wave Propagation From Electrons to Photonic Crystals and Left-Handed Materials

    CERN Document Server

    Markos, Peter

    2010-01-01

    This textbook offers the first unified treatment of wave propagation in electronic and electromagnetic systems and introduces readers to the essentials of the transfer matrix method, a powerful analytical tool that can be used to model and study an array of problems pertaining to wave propagation in electrons and photons. It is aimed at graduate and advanced undergraduate students in physics, materials science, electrical and computer engineering, and mathematics, and is ideal for researchers in photonic crystals, negative index materials, left-handed materials, plasmonics, nonlinear effects,

  6. Ductile damage prediction in sheet and bulk metal forming

    Science.gov (United States)

    Badreddine, Houssem; Labergère, Carl; Saanouni, Khemais

    2016-04-01

    This paper is dedicated to the presentation of an advanced 3D numerical methodology for virtual sheet and/or bulk metal forming simulation to predict the anisotropic ductile defects occurrence. First, the detailed formulation of thermodynamically-consistent fully coupled and fully anisotropic constitutive equations is given. The proposed constitutive equations account for the main material nonlinearities as the anisotropic plastic flow, the mixed isotropic and kinematic hardening and the anisotropic ductile damage under large inelastic strains. Second, the related numerical aspects required to solve the initial and boundary value problem (IBVP) are very briefly presented in the framework of the 3D finite element method. The global resolution schemes as well as the local integration schemes of the fully coupled constitutive equations are briefly discussed. Finally, some typical examples of sheet and bulk metal forming processes are numerically simulated using the proposed numerical methodology.

  7. Magnetizing of permanent magnets using HTS bulk magnets

    Science.gov (United States)

    Oka, Tetsuo; Muraya, Tomoki; Kawasaki, Nobutaka; Fukui, Satoshi; Ogawa, Jun; Sato, Takao; Terasawa, Toshihisa

    2012-01-01

    A demagnetized Nd-Fe-B permanent magnet was scanned just above the magnetic pole which contains the HTS bulk magnet generating a magnetic field of 3.27 T. The magnet sample was subsequently found to be fully magnetized in the open space of the static magnetic fields. We examined the magnetic field distributions when the magnetic poles were scanned twice to activate the magnet plate inversely with various overlap distances between the tracks of the bulk magnet. The magnetic field of the "rewritten" magnet reached the values of the magnetically saturated region of the material, showing steep gradients at the border of each magnetic pole. As a replacement for conventional pulse field magnetizing methods, this technique is proposed to expand the degree of freedom in the design of electromagnetic devices, and is proposed as a novel practical method for magnetizing rare-earth magnets, which have excellent magnetic performance and require intense fields of more than 3 T to be activated.

  8. Structural Characterization of Carbon Nanomaterial Film In Situ Synthesized on Various Bulk Metals

    Directory of Open Access Journals (Sweden)

    J. Y. Xu

    2014-01-01

    Full Text Available Carbon nanofiber films were prepared via a simple chemical vapor deposition (CVD method on various bulk metal substrates including bulk 316 L stainless steel, pure cobalt, and pure nickel treated by surface mechanical attrition treatment (SMAT. The microstructures of the carbon nanomaterial film were studied by SEM, TEM, XRD, and Raman spectroscopy. In this paper, bulk metallic materials treated by SMAT served as substrates as well as catalysts for carbon nanomaterial film formation. The results indicate that the carbon nanofiber films are formed concerning the catalytic effects of the refined metallic particles during CVD on the surface of SMAT-treated bulk metal substrates. However, distinguished morphologies of carbon nanomaterial film are displayed in the case of the diverse bulk metal substrates.

  9. Technical specifications for the bulk shielding reactor

    International Nuclear Information System (INIS)

    This report provides information concerning the technical specifications for the Bulk Shielding Reactor. Areas covered include: safety limits and limiting safety settings; limiting conditions for operation; surveillance requirements; design features; administrative controls; and monitoring of airborne effluents. 10 refs

  10. Faecal bulking efficacy of Australasian breakfast cereals.

    Science.gov (United States)

    Monro, John A

    2002-01-01

    Faecal bulk may play an important role in preventing a range of disorders of the large bowel, but as yet there is little information available on the relative faecal bulking capacities of various foods. Breakfast cereals are often promoted as a good source of potential bulk for 'inner health' because they provide dietary fibre, but their relative abilities to provide faecal bulk per se have not been described. The faecal bulking efficacy of 28 representative Australasian breakfast cereals was therefore measured. A rat model developed for the purpose, and shown to give similar responses as humans to cereal fibres, was used to measure faecal bulking efficacy as increases in fully hydrated faecal weight/100 g diet, based on precise measurements of food intake, faecal dry matter output and faecal water-holding capacity (g water held without stress/g faecal dry matter). Compared to a baseline diet containing 50% sucrose, increments in hydrated faecal weight due to 50% breakfast cereal ranged from slightly negative (Cornflakes, -2 g/100 g diet) to about 80 g/100 g diet (San Bran). Most breakfast cereals increased hydrated faecal weight by between 10 and 20 g/100 g diet from a baseline of 21 +/- 1.5 g/100 g diet, but four products containing high levels of wheat bran had an exceptionally large impact on hydrated faecal weight (increment > 20 g/100 g diet), and the changes resulted more from relative changes in dry matter output than in faecal water retention/gram. However, as faecal water retention was about 2.5 g water/g faecal dry matter on average, increases in dry matter represented large increases in faecal water load. Faecal bulking indices (FBI) for most of the breakfast cereals were less than 20 (wheat bran = 100). The content of wheat bran equivalents for faecal bulk (WBE(fb)) in the breakfast cereals was calculated from FBI. Most breakfast cereals contributed, per serve, less than 10% of a theoretical daily reference value for faecal bulk (DRV(fb) = 63 WBE

  11. Determination of energy levels in organic bulk-heterojunction systems

    Energy Technology Data Exchange (ETDEWEB)

    Wetzstein, Holger; Krause, Stefan; Schoell, Achim; Reinert, Friedrich [Experimental Physics VII, Julius-Maximilians-University of Wuerzburg, D-97074 Wuerzburg (Germany); Liedtke, Moritz; Kern, Julia; Deibel, Carsten [Experimental Physics VI, Julius-Maximilians-University of Wuerzburg, D-97074 Wuerzburg (Germany)

    2010-07-01

    In order to improve the efficiency of electronic devices based on organic semiconducting materials the detailed knowledge about the exact position of the energy levels responsible for charge transport is crucial. The experimental determination is particularly complicated for bulk heterojunctions of p- and n-conducting materials in terms of sample preparation, film morphology and distinction of the different spectroscopic signatures. We investigated four promising materials for organic photovoltaic devices: the electron donor poly(3-hexylthiophene-2,5-diyl) (P3HT) and the three electron acceptors [6,6]-phenyl-C{sub 61} butyric acid methyl ester (PC{sub 60}BM), its bisadduct analogue (bis- PC{sub 60}BM) and [6,6]-phenyl-C{sub 71} butyric acid methyl ester (PC{sub 70}BM). Thin films of pristine materials as well as bulk heterojunction samples of P3HT:PC{sub 60}BM, P3HT:bis-PC{sub 60}BM and P3HT:PC{sub 70}BM were examined with respect to their valence levels using ultraviolet photoelectron spectroscopy (UPS).

  12. Orbital magnetization in insulators: Bulk versus surface

    Science.gov (United States)

    Bianco, Raffaello; Resta, Raffaele

    2016-05-01

    The orbital magnetic moment of a finite piece of matter is expressed in terms of the one-body density matrix as a simple trace. We address a macroscopic system, insulating in the bulk, and we show that its orbital moment is the sum of a bulk term and a surface term, both extensive. The latter only occurs when the transverse conductivity is nonzero and it is due to conducting surface states. Simulations on a model Hamiltonian validate our theory.

  13. An intrinsic mobility ceiling of Si bulk

    OpenAIRE

    Garcia-Castello, Nuria; Prades, Joan Daniel; Cirera, Albert

    2011-01-01

    We compute by Density Functional Theory-Non Equilibrium Green Functions Formalism (DFT-NEGFF) the conductance of bulk Si along different crystallographic directions. We find a ceiling value for the intrinsic mobility of bulk silicon of $8.4\\cdot10^6 cm^2/V\\cdot s$. We suggest that this result is related to the lowest effective mass of the $$ direction.

  14. Numerical modelling and comparison of MgB2 bulks fabricated by HIP and infiltration growth

    Science.gov (United States)

    Zou, J.; Ainslie, M. D.; Fujishiro, H.; Bhagurkar, A. G.; Naito, T.; Babu, N. Hari; Fagnard, J.-F.; Vanderbemden, P.; Yamamoto, A.

    2015-07-01

    MgB2 in bulk form shows great promise as trapped field magnets (TFMs) as an alternative to bulk (RE)BCO materials to replace permanent magnets in applications such as rotating machines, magnetic bearings and magnetic separation, and the relative ease of fabrication of MgB2 materials has enabled a number of different processing techniques to be developed. In this paper, a comparison is made between bulk MgB2 samples fabricated by the hot isostatic pressing (HIP), with and without Ti-doping, and infiltration growth (IG) methods and the highest trapped field in an IG-processed bulk MgB2 sample, Bz = 2.12 at 5 K and 1.66 T at 15 K, is reported. Since bulk MgB2 has a more homogeneous Jc distribution than (RE)BCO bulks, studies on such systems are made somewhat easier because simplified assumptions regarding the geometry and Jc distribution can be made, and a numerical simulation technique based on the 2D axisymmetric H-formulation is introduced to model the complete process of field cooling (FC) magnetization. As input data for the model, the measured Jc(B,T) characteristics of a single, small specimen taken from each bulk sample are used, in addition to measured specific heat and thermal conductivity data for the materials. The results of the simulation reproduce the experimental results extremely well: (1) indicating the samples have excellent homogeneity, and (2) validating the numerical model as a fast, accurate and powerful tool to investigate the trapped field profile of bulk MgB2 discs of any size accurately, under any specific operating conditions. Finally, the paper is concluded with a numerical analysis of the influence of the dimensions of the bulk sample on the trapped field.

  15. 350 keV accelerator based PGNAA setup to detect nitrogen in bulk samples

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A., E-mail: aanaqvi@kfupm.edu.sa [Department of Physics and King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Al-Matouq, Faris A.; Khiari, F.Z.; Gondal, M.A.; Rehman, Khateeb-ur [Department of Physics and King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Isab, A.A. [Department of Chemistry, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Raashid, M.; Dastageer, M.A. [Department of Physics and King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

    2013-11-21

    Nitrogen concentration was measured in explosive and narcotics proxy material, e.g. anthranilic acid, caffeine, melamine, and urea samples, bulk samples through thermal neutron capture reaction using 350 keV accelerator based prompt gamma ray neutron activation (PGNAA) setup. Intensity of 2.52, 3.53–3.68, 4.51, 5.27–5.30 and 10.38 MeV prompt gamma rays of nitrogen from the bulk samples was measured using a cylindrical 100 mm×100 mm (diameter×height ) BGO detector. Inspite of interference of nitrogen gamma rays from bulk samples with capture prompt gamma rays from BGO detector material, an excellent agreement between the experimental and calculated yields of nitrogen gamma rays has been obtained. This is an indication of the excellent performance of the PGNAA setup for detection of nitrogen in bulk samples.

  16. 350 keV accelerator based PGNAA setup to detect nitrogen in bulk samples

    International Nuclear Information System (INIS)

    Nitrogen concentration was measured in explosive and narcotics proxy material, e.g. anthranilic acid, caffeine, melamine, and urea samples, bulk samples through thermal neutron capture reaction using 350 keV accelerator based prompt gamma ray neutron activation (PGNAA) setup. Intensity of 2.52, 3.53–3.68, 4.51, 5.27–5.30 and 10.38 MeV prompt gamma rays of nitrogen from the bulk samples was measured using a cylindrical 100 mm×100 mm (diameter×height ) BGO detector. Inspite of interference of nitrogen gamma rays from bulk samples with capture prompt gamma rays from BGO detector material, an excellent agreement between the experimental and calculated yields of nitrogen gamma rays has been obtained. This is an indication of the excellent performance of the PGNAA setup for detection of nitrogen in bulk samples

  17. 350 keV accelerator based PGNAA setup to detect nitrogen in bulk samples

    Science.gov (United States)

    Naqvi, A. A.; Al-Matouq, Faris A.; Khiari, F. Z.; Gondal, M. A.; Rehman, Khateeb-ur; Isab, A. A.; Raashid, M.; Dastageer, M. A.

    2013-11-01

    Nitrogen concentration was measured in explosive and narcotics proxy material, e.g. anthranilic acid, caffeine, melamine, and urea samples, bulk samples through thermal neutron capture reaction using 350 keV accelerator based prompt gamma ray neutron activation (PGNAA) setup. Intensity of 2.52, 3.53-3.68, 4.51, 5.27-5.30 and 10.38 MeV prompt gamma rays of nitrogen from the bulk samples was measured using a cylindrical 100 mm×100 mm (diameter×height ) BGO detector. Inspite of interference of nitrogen gamma rays from bulk samples with capture prompt gamma rays from BGO detector material, an excellent agreement between the experimental and calculated yields of nitrogen gamma rays has been obtained. This is an indication of the excellent performance of the PGNAA setup for detection of nitrogen in bulk samples.

  18. Bulk elastic waves with unidirectional backscattering-immune topological states in a time-dependent superlattice

    Energy Technology Data Exchange (ETDEWEB)

    Swinteck, N., E-mail: swinteck@email.arizona.edu; Matsuo, S.; Runge, K.; Lucas, P.; Deymier, P. A. [Department of Materials Science and Engineering, University of Arizona, Tucson, Arizona 85721 (United States); Vasseur, J. O. [Institut d' Electronique, de Micro-électronique et de Nanotechnologie, UMR CNRS 8520, Cité Scientifique, 59652 Villeneuve d' Ascq Cedex (France)

    2015-08-14

    Recent progress in electronic and electromagnetic topological insulators has led to the demonstration of one way propagation of electron and photon edge states and the possibility of immunity to backscattering by edge defects. Unfortunately, such topologically protected propagation of waves in the bulk of a material has not been observed. We show, in the case of sound/elastic waves, that bulk waves with unidirectional backscattering-immune topological states can be observed in a time-dependent elastic superlattice. The superlattice is realized via spatial and temporal modulation of the stiffness of an elastic material. Bulk elastic waves in this superlattice are supported by a manifold in momentum space with the topology of a single twist Möbius strip. Our results demonstrate the possibility of attaining one way transport and immunity to scattering of bulk elastic waves.

  19. Dispersion regions overlapping for bulk and surface polaritons in a magnetic-semiconductor superlattice

    CERN Document Server

    Fesenko, Volodymyr I; Tuz, Vladimir R

    2016-01-01

    Extraordinary dispersion features of both bulk and surface polaritons in a finely-stratified magnetic-semiconductor structure which is under an action of an external static magnetic field in the Voigt geometry are discussed in this letter. It is shown that the conditions for total overlapping dispersion regions of simultaneous existence of bulk and surface polaritons can be reached providing a conscious choice of the constitutive parameters and material fractions for both magnetic and semiconductor subsystems.

  20. Synthesis and magnetic properties of bulk transparent PMMA/Fe-oxide nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Li Shanghua; Qin Jian; Fornara, Andrea; Toprak, Muhammet; Muhammed, Mamoun [Division of Functional Materials, Royal Institute of Technology (KTH), SE-16440 Kista, Stockholm (Sweden); Kim, Do Kyung [Institute for Science and Technology in Medicine, Keele University Medical School, Stoke-on-Trent ST4 7QB (United Kingdom)], E-mail: shanghua@kth.se

    2009-05-06

    PMMA/Fe-oxide nanocomposites are fabricated by a chemical method. Monodispersed Fe-oxide nanoparticles are well dispersed in the PMMA matrix by in situ polymerization, resulting in a bulk transparent polymeric nanocomposite. The magnetic behavior of the PMMA/Fe-oxide nanocomposites is investigated. The transparent PMMA/Fe-oxide nanocomposite has potentially interesting magneto-optic applications without compromising the advantages of a lightweight, noncorrosive polymeric material with very high transparency even for bulk samples.

  1. 77 FR 14327 - Bulk Packaging To Allow for Transfer of Hazardous Liquid Cargoes

    Science.gov (United States)

    2012-03-09

    ..., issue of the Federal Register (73 FR 3316). D. Public Meeting We do not now plan to hold a public... FR Federal Register HMR Hazardous Materials Regulations; 49 CFR Parts 171-180 IBC Intermediate Bulk... Materials by Vessel'' (55 FR 37406), the Coast Guard allowed the use of Intermodal (IM) 101 and IM...

  2. Enhanced bulk modulus and reduced transition pressure in gamma-Fe2O3 nanocrystals

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Olsen, J. Staun; Gerward, Leif;

    1998-01-01

    GPa for the bulk material to 305 GPa for 9 nm size crystals. At the same time the transition pressure decreases from 35 to 27 GPa. The reduced transition pressure is explained in terms of nucleation and growth, the larger volume change upon transition in the nanocrystalline material being the main...

  3. Bipolar electrical coil based on YBCO bulks: initial tests

    International Nuclear Information System (INIS)

    In the field of the application of HTS in electrical motors, most prototypes are made using superconducting coils based on tape and located in the position where copper coils work in a similar conventional motor. Other prototypes use superconducting bulks (usually disk-shaped) in those positions where normal magnets should work in similar conventional motors. But it is very unusual to find designs using electrical coils based on bulks. This is a challenge whose main problem is the difficulty in machining the superconductor bulks to get the proper shape because of the impossibility of bending the material to wind coils. The design of a bipolar single-turn coil made from a superconducting YBCO disk was proposed by the group of Electrical Application of Superconductors, at the University of Extremadura, several years ago to be an element for the design of a modular two-phase inductor for an air core axial-flux motor. The shape of each coil looks like an 'S'. When a current flows through the circuit, two opposite magnetic fields appear in the upper and lower halves of the piece. Until now, attempts to get a good superconducting circuit by cutting a YBCO disk into the required shape have failed because of cracks appearing in the crystal during the process. Last year, our group at the University of Extremadura began to work with ATZ GmbH who have improved the machining process and made the coils. In this paper we present the coil and the first tests carried out

  4. EFFECTIVE POROSITY IMPLIES EFFECTIVE BULK DENSITY IN SORBING SOLUTE TRANSPORT

    Energy Technology Data Exchange (ETDEWEB)

    Flach, G.

    2012-02-27

    The concept of an effective porosity is widely used in solute transport modeling to account for the presence of a fraction of the medium that effectively does not influence solute migration, apart from taking up space. This non-participating volume or ineffective porosity plays the same role as the gas phase in single-phase liquid unsaturated transport: it increases pore velocity, which is useful towards reproducing observed solute travel times. The prevalent use of the effective porosity concept is reflected by its prominent inclusion in popular texts, e.g., de Marsily (1986), Fetter (1988, 1993) and Zheng and Bennett (2002). The purpose of this commentary is to point out that proper application of the concept for sorbing solutes requires more than simply reducing porosity while leaving other material properties unchanged. More specifically, effective porosity implies the corresponding need for an effective bulk density in a conventional single-porosity model. The reason is that the designated non-participating volume is composed of both solid and fluid phases, both of which must be neglected for consistency. Said another way, if solute does not enter the ineffective porosity then it also cannot contact the adjoining solid. Conceptually neglecting the fluid portion of the non-participating volume leads to a lower (effective) porosity. Likewise, discarding the solid portion of the non-participating volume inherently leads to a lower or effective bulk density. In the author's experience, practitioners virtually never adjust bulk density when adopting the effective porosity approach.

  5. Experimental demonstration of surface and bulk plasmon polaritons in hypergratings

    Science.gov (United States)

    Sreekanth, Kandammathe Valiyaveedu; de Luca, Antonio; Strangi, Giuseppe

    2013-11-01

    Hyperbolic metamaterials (HMMs) represent a novel class of fascinating anisotropic plasmonic materials, supporting highly confined bulk plasmon polaritons in addition to the surface plasmon polaritons. However, it is very challenging to tailor and excite those modes at optical frequencies using prism coupling technique because of the intrinsic difficulties to engineer non-traditional optical properties using artificial nanostructures and the unavailability of high refractive index prisms for matching the momentum between the incident light and the guided modes. Here, we experimentally demonstrate the excitation of both surface and bulk plasmon polaritons in a HMM through a grating coupling technique of surface plasmon excitation that makes use a hypergrating, which is a combined structure of metallic diffraction grating and HMM. Initially, we propose an optical hyperbolic metamaterial based on Au/TiO2 multilayers and confirm the hyperbolic dispersion, and the presence of high-k modes in the fabricated HMM. Reflection measurements as a function of incident angle and excitation wavelength show the existence of both surface and bulk plasmon polaritons inside the hypergrating. The proposed configuration is expected to find potential applications in bio-chemical sensors, integrated optics and optical sub-wavelength imaging.

  6. Bipolar electrical coil based on YBCO bulks: initial tests

    Science.gov (United States)

    Alvarez, A.; Suárez, P.; Ceballos, J. M.; Pérez, B.; Werfel, F.; Floegel-Delor, U.

    2008-02-01

    In the field of the application of HTS in electrical motors, most prototypes are made using superconducting coils based on tape and located in the position where copper coils work in a similar conventional motor. Other prototypes use superconducting bulks (usually disk-shaped) in those positions where normal magnets should work in similar conventional motors. But it is very unusual to find designs using electrical coils based on bulks. This is a challenge whose main problem is the difficulty in machining the superconductor bulks to get the proper shape because of the impossibility of bending the material to wind coils. The design of a bipolar single-turn coil made from a superconducting YBCO disk was proposed by the group of Electrical Application of Superconductors, at the University of Extremadura, several years ago to be an element for the design of a modular two-phase inductor for an air core axial-flux motor. The shape of each coil looks like an 'S'. When a current flows through the circuit, two opposite magnetic fields appear in the upper and lower halves of the piece. Until now, attempts to get a good superconducting circuit by cutting a YBCO disk into the required shape have failed because of cracks appearing in the crystal during the process. Last year, our group at the University of Extremadura began to work with ATZ GmbH who have improved the machining process and made the coils. In this paper we present the coil and the first tests carried out.

  7. Formation of cerium-based bulk metallic glasses

    International Nuclear Information System (INIS)

    We report the formation and composition range of Ce-based bulk metallic glasses. Ternary Ce-Al-Cu(Co,Ni) glassy rods of 1-3 mm in diameter can be easily formed in a wide composition range by a conventional copper mold cast method. Substituting Ce with low-cost Ce-rich misch metal (MM), MM-Al-Cu bulk glasses with a similar high glass-forming ability (GFA) can be obtained. With minor addition of extra elements such as Fe, Co, Ni, Nb, Zn and Si, the critical diameter of the full glassy rods of the Ce-Al-Cu matrix can be markedly enhanced from 2 mm to at least 3-10 mm. It is found that the often-cited empirical criteria for bulk metallic glass formation cannot interpret the formation and the addition effect on GFA of the metallic glasses. The striking effect and mechanism of microalloying on the GFA of the metallic glasses are studied. These materials with extremely low glass transition temperatures (341-439 K, even below the boiling temperature of water) and excellent deformability at low temperatures could have potential applications

  8. Oxygen Behavior in Bulk Amorphous Zr-base Alloy

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Bulk Zr55Al10Ni5Cu30 metallic glass plates with a dimension of 85 mm×35mm×4 mm and a complicated plate werefabricated by injecting casting method using spongy zirconium and industrial purity aluminum, nickel and copper asraw materials. It was shown that the holding time of liquid metals at elevated temperatures had a great influence onthe oxygen content of the plates due to the contamination resulting from the atmosphere. Increasing holding timeresulted in the increase of oxygen content in the injected alloy. The glass transition temperatures of the bulk metallicglass plates are higher than that reported in the literature and crystallization temperature is lower for the one withhigher oxygen content at the same heating rate. The extension of the undercooled liquid region △Tx reaching about87 K is 3 K higher than that previously reported and 26 K higher than that with oxygen content of 0.076 wt pct forthe one with oxygen content as high as 0.065 wt pct. Therefore the oxygen content of the alloy has a significantinfluence on the glass forming ability and thermal stability of bulk metal glass. It is suggested that direct correlationbetween high glass forming ability and large △Tx is only valid for a well-defined Iow oxygen concentration or has tobe reconsidered by incorporating oxygen as an additional alloying element.

  9. Permanent magnet with MgB2 bulk superconductor

    Science.gov (United States)

    Yamamoto, Akiyasu; Ishihara, Atsushi; Tomita, Masaru; Kishio, Kohji

    2014-07-01

    Superconductors with persistent zero-resistance currents serve as permanent magnets for high-field applications requiring a strong and stable magnetic field, such as magnetic resonance imaging. The recent global helium shortage has quickened research into high-temperature superconductors (HTSs)—materials that can be used without conventional liquid-helium cooling to 4.2 K. Herein, we demonstrate that 40-K-class metallic HTS magnesium diboride (MgB2) makes an excellent permanent bulk magnet, maintaining 3 T at 20 K for 1 week with an extremely high stability (Tesla-class permanent-magnet applications.

  10. Applications and modelling of bulk HTSs in brushless ac machines

    International Nuclear Information System (INIS)

    The use of high temperature superconducting material in its bulk form for engineering applications is attractive due to the large power densities that can be achieved. In brushless electrical machines, there are essentially four properties that can be exploited; their hysteretic nature, their flux shielding properties, their ability to trap large flux densities and their ability to produce levitation. These properties translate to hysteresis machines, reluctance machines, trapped-field synchronous machines and linear motors respectively. Each one of these machines is addressed separately and computer simulations that reveal the current and field distributions within the machines are used to explain their operation. (author)

  11. Soliton interaction in quadratic and cubic bulk media

    DEFF Research Database (Denmark)

    Johansen, Steffen Kjær; Bang, Ole

    2000-01-01

    Summary form only given. The understanding of how and to what extend the cubic nonlinearity affects beam propagation and spatial soliton formation in quadratic media is of vital importance in fundamental and applied nonlinear physics. We consider beam propagation under type-I SHG conditions in...... lossless bulk second order nonlinear optical materials with a nonvanishing third order nonlinearity. It is known that in pure second order systems a single soliton can never collapse whereas in systems with both nonlinearities and that stable single soliton propagation can only in some circumstances be...

  12. Improvement of Mechanical Properties on a Surface of Bulk Ceramics

    Czech Academy of Sciences Publication Activity Database

    Ctibor, Pavel; Kraus, L.

    Trollhättan : University West, 2009 - (Sudarshan, T.; Nylen, P.), s. 247-254 ISBN 978-0-9817065-1-1. [International Conference on Surface Modification Technologies SMT22/22./. Trollhättan (SE), 22.09.2008-24.09.2008] R&D Projects: GA AV ČR 1QS200430560 Institutional research plan: CEZ:AV0Z20430508 Keywords : Bulk ceramics * plasma post-treatment * diode laser * wear resistance * mechanical testing Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass

  13. BEHAVIORS OF BULK METALLIC GLASS UNDER SHOCK LOADING

    OpenAIRE

    ATROSHENKO S.A.

    2016-01-01

    The high-strain-rate method of materials for dynamic strength investigations under micro and sub-microsecond durations of shock loads on the base of electrical explosion of conductors was developed. The experimental investigations of dynamic properties for bulk metallic glass on the base of Ti and Zr under shock loads of sub-microsecond duration (~0.5-0.7 μs) in the pressure range up to 12 GPa were carried out. The values of Hugoniot elastic limit (HEL) and spall strength for these amorphous ...

  14. Electronics materials research

    Science.gov (United States)

    1982-01-01

    The electronic materials and is aimed at the establishment of quantitative relationships underlying crystal growth parameters, materials properties, electronic characteristics and device applications. The overall program evolves about the following main thrust areas: (1) crystal growth novel approaches to engineering of semiconductor materials; (2) investigation of materials properties and electronic characteristics on a macro and microscale; (3) surface properties and surface interactions with the bulk and ambients; (4) electronic properties controlling device applications and device performance.

  15. Bulk nucleation and growth of inorganic nanowires and nanotubes

    Science.gov (United States)

    Sharma, Shashank

    The nanometer scale materials such as nanowires and nanotubes will be of particular interest as building blocks for designing novel sensors, catalysts, electronic, optical, and optoelectronic devices. However, in order to realize these applications, bulk amounts of nanowires and nanotubes need to be synthesized with precise control over the nanostructure characteristics. In addition, the structure-property relationships for one-dimensional structures are expected to be different than their bulk when their diameters are less than a characteristic Bohr exciton radius. This fundamental curiosity also necessitates bulk synthesis of nanostructures. The current bulk nanowire synthesis methods utilize either nanometer scale porous molds or nanometer scale transition metal clusters to template one-dimensional growth. All these techniques have inherent limitations in terms of control over the nanowire diameter distribution, composition, the growth direction, and the ability to generate abrupt interfaces within individual nanowires. In this dissertation, a new concept for bulk nucleation and growth of one-dimensional nanostructures is proposed and demonstrated for a variety of inorganic material systems. In this technique, multiple nanowires nucleate and grow from pools of low-melting metal melts when exposed to an activated gas phase containing the necessary precursors. This concept, hereby termed Low Melting Metals and Activated Gas phase (LMAG) mediated method, is specifically demonstrated for the synthesis of, (a) silicon nanowires grown using molten gallium and silane precursors; (b) silicon compound nanowires using solution of molten gallium and appropriate gas phase precursors, and (c) metal-oxide nanostructures grown using direct reaction of the respective metal melts and oxygen precursors. Nanowires resulted from the same molten gallium pool at high densities (>1011/cm2) and with narrow diameter distribution. The silicon nanowires synthesized using the LMAG

  16. Fabrication of ternary Ca-Mg-Zn bulk metallic glasses

    Directory of Open Access Journals (Sweden)

    R. Nowosielski

    2013-02-01

    Full Text Available Purpose: The paper describes the preparation, structure and thermal properties of ternary Ca-Mg-Zn bulk metallic glass in form of as-cast rods.Design/methodology/approach: The investigations on the ternary Ca-Mg-Zn glassy rods were conducted by using X-ray diffraction (XRD, scanning electron microscopy (SEM which energy dispersive X-ray analysis (EDS.Findings: The X-ray diffraction investigations have revealed that the studied as-cast rod was amorphous. The fractures of studied alloy could be classified as mixed fracture with indicated “river” and “smooth” fractures. Both type of the fracture surfaces consist of weakly formed “river” and “shell” patterns and “smooth” regions. The “river” patterns are characteristic for metallic glassy alloys.Practical implications: The studied Ca-based bulk metallic glasses is a relatively new group of material. Ca-based bulk metallic glasses are applied for many applications in different elements. Ca-based bulk metallic glasses have many unique properties such as low density (~2.0 g/cm3, low Youn g’s modulus ( ~20 to 30 GPa. The elastic modulus of Ca-b ased BMGs is comparable to that of hum an bone s, and Ca, Mg, and Zn are biocompatible. These features make the Ca-Mg-Zn–based alloys attractive for use in biomedical applications.Originality/value: Fabrication of amorphous alloy in the form of rod ternary Ca-Mg-Zn alloy by pressure die casting method.

  17. A diphoton resonance from bulk RS

    Science.gov (United States)

    Csáki, Csaba; Randall, Lisa

    2016-07-01

    Recent LHC data hinted at a 750 GeV mass resonance that decays into two photons. A significant feature of this resonance is that its decays to any other Standard Model particles would be too low to be detected so far. Such a state has a compelling explanation in terms of a scalar or a pseudoscalar that is strongly coupled to vector states charged under the Standard Model gauge groups. Such a scenario is readily accommodated in bulk RS with a scalar localized in the bulk away from but close to the Higgs. Turning this around, we argue that a good way to find the elusive bulk RS model might be the search for a resonance with prominent couplings to gauge bosons.

  18. Micro benchtop optics by bulk silicon micromachining

    Science.gov (United States)

    Lee, Abraham P.; Pocha, Michael D.; McConaghy, Charles F.; Deri, Robert J.

    2000-01-01

    Micromachining of bulk silicon utilizing the parallel etching characteristics of bulk silicon and integrating the parallel etch planes of silicon with silicon wafer bonding and impurity doping, enables the fabrication of on-chip optics with in situ aligned etched grooves for optical fibers, micro-lenses, photodiodes, and laser diodes. Other optical components that can be microfabricated and integrated include semi-transparent beam splitters, micro-optical scanners, pinholes, optical gratings, micro-optical filters, etc. Micromachining of bulk silicon utilizing the parallel etching characteristics thereof can be utilized to develop miniaturization of bio-instrumentation such as wavelength monitoring by fluorescence spectrometers, and other miniaturized optical systems such as Fabry-Perot interferometry for filtering of wavelengths, tunable cavity lasers, micro-holography modules, and wavelength splitters for optical communication systems.

  19. Bulk amorphous Mg-based alloys

    DEFF Research Database (Denmark)

    Pryds, Nini

    The present paper describes the preparation and properties of bulk amorphous quarternary Mg-based alloys and the influence of additional elements on the ability of the alloy to form bulk amorphous. The main goal is to find a Mg-based alloy system which shows both high strength to weight ratio and a...... low glass transition temperature. The alloys were prepared by using a relatively simple technique, i.e. rapid cooling of the melt in a copper wedge mould. The essential structural changes that are achieved by going from the amorphous to the crystalline state through the supercooled liquid state are...... discussed in this paper. On the basis of these measurements phase diagrams of the different systems were constructed. Finally, it is demonstrated that when pressing the bulk amorphous alloy onto a metallic dies at temperatures within the supercooled liquid region, the alloy faithfully replicates the surface...

  20. Orchestrating Bulk Data Movement in Grid Environments

    Energy Technology Data Exchange (ETDEWEB)

    Vazhkudai, SS

    2005-01-25

    Data Grids provide a convenient environment for researchers to manage and access massively distributed bulk data by addressing several system and transfer challenges inherent to these environments. This work addresses issues involved in the efficient selection and access of replicated data in Grid environments in the context of the Globus Toolkit{trademark}, building middleware that (1) selects datasets in highly replicated environments, enabling efficient scheduling of data transfer requests; (2) predicts transfer times of bulk wide-area data transfers using extensive statistical analysis; and (3) co-allocates bulk data transfer requests, enabling parallel downloads from mirrored sites. These efforts have demonstrated a decentralized data scheduling architecture, a set of forecasting tools that predict bandwidth availability within 15% error and co-allocation architecture, and heuristics that expedites data downloads by up to 2 times.

  1. Bulk Comptonization by Turbulence in Accretion Disks

    CERN Document Server

    Kaufman, J

    2016-01-01

    Radiation pressure dominated accretion discs around compact objects may have turbulent velocities that greatly exceed the electron thermal velocities within the disc. Bulk Comptonization by the turbulence may therefore dominate over thermal Comptonization in determining the emergent spectrum. Bulk Comptonization by divergenceless turbulence is due to radiation viscous dissipation only. It can be treated as thermal Comptonization by solving the Kompaneets equation with an equivalent "wave" temperature, which is a weighted sum over the power present at each scale in the turbulent cascade. Bulk Comptonization by turbulence with non-zero divergence is due to both pressure work and radiation viscous dissipation. Pressure work has negligible effect on photon spectra in the limit of optically thin turbulence, and in this limit radiation viscous dissipation alone can be treated as thermal Comptonization with a temperature equivalent to the full turbulent power. In the limit of extremely optically thick turbulence, ra...

  2. Thermal relics in cosmology with bulk viscosity

    International Nuclear Information System (INIS)

    In this paper we discuss some consequences of cosmological models in which the primordial cosmic matter is described by a relativistic imperfect fluid. The latter takes into account the dissipative effects (bulk viscosity) arising from different cooling rates of the fluid components in the expanding Universe. We discuss, in particular, the effects of the bulk viscosity on Big Bang Nucleosynthesis and on the thermal relic abundance of particles, looking at recent results of PAMELA experiment. The latter has determined an anomalous excess of positron events, which cannot be explained by conventional cosmology and particle physics. (orig.)

  3. Radiation-hardened bulk CMOS technology

    International Nuclear Information System (INIS)

    The evolutionary development of a radiation-hardened bulk CMOS technology is reviewed. The metal gate hardened CMOS status is summarized, including both radiation and reliability data. The development of a radiation-hardened bulk silicon gate process which was successfully implemented to a commercial microprocessor family and applied to a new, radiation-hardened, LSI standard cell family is also discussed. The cell family is reviewed and preliminary characterization data is presented. Finally, a brief comparison of the various radiation-hardened technologies with regard to performance, reliability, and availability is made

  4. Thermal relics in cosmology with bulk viscosity

    Energy Technology Data Exchange (ETDEWEB)

    Iorio, A. [Charles University in Prague, Faculty of Mathematics and Physics, Prague (Czech Republic); Lambiase, G. [Universita di Salerno, Dipartimento di Fisica E.R. Caianiello, Fisciano (Italy); INFN, Gruppo Collegato di Salerno, Fisciano (Italy)

    2015-03-01

    In this paper we discuss some consequences of cosmological models in which the primordial cosmic matter is described by a relativistic imperfect fluid. The latter takes into account the dissipative effects (bulk viscosity) arising from different cooling rates of the fluid components in the expanding Universe. We discuss, in particular, the effects of the bulk viscosity on Big Bang Nucleosynthesis and on the thermal relic abundance of particles, looking at recent results of PAMELA experiment. The latter has determined an anomalous excess of positron events, which cannot be explained by conventional cosmology and particle physics. (orig.)

  5. Bulk Entropy in Loop Quantum Gravity

    OpenAIRE

    Livine, Etera R; Terno, Daniel R.

    2007-01-01

    In the framework of loop quantum gravity (LQG), having quantum black holes in mind, we generalize the previous boundary state counting (gr-qc/0508085) to a full bulk state counting. After a suitable gauge fixing we are able to compute the bulk entropy of a bounded region (the "black hole") with fixed boundary. This allows us to study the relationship between the entropy and the boundary area in details and we identify a holographic regime of LQG where the leading order of the entropy scales w...

  6. Bulk Entropy in Loop Quantum Gravity

    CERN Document Server

    Livine, Etera R

    2007-01-01

    In the framework of loop quantum gravity (LQG), having quantum black holes in mind, we generalize the previous boundary state counting (gr-qc/0508085) to a full bulk state counting. After a suitable gauge fixing we are able to compute the bulk entropy of a bounded region (the "black hole") with fixed boundary. This allows us to study the relationship between the entropy and the boundary area in details and we identify a holographic regime of LQG where the leading order of the entropy scales with the area. We show that in this regime we can fine tune the factor between entropy and area without changing the Immirzi parameter.

  7. Mechanical behavior of a bulk nanostructured iron alloy

    Science.gov (United States)

    Carsley, J. E.; Fisher, A.; Milligan, W. W.; Aifantis, E. C.

    1998-09-01

    Bulk, fully dense materials were prepared from Fe-10Cu with grain diameters between 45 nm and 1.7 µm. The materials were prepared by ball milling of powders in a glove box, followed by hot isostatic pressing (hipping) or powder forging. Larger grain sizes were obtained by thermal treatment of the consolidated powders. The bulk materials were relatively clean, with oxygen levels below 1500 wpm and other contaminants less than 0.1 at. pct. The mechanical behavior of these materials was unique. At temperatures from 77 to 470 K, the first and only mechanism of plastic deformation was intense shear banding, which was accompanied by a perfectly plastic stress-strain response (absence of strain hardening). There was a large tension-compression asymmetry in the strength, and the shear bands did not occur on the plane of maximum shear stress or the plane of zero extension. This behavior, while unusual for metals, has been observed in amorphous polymers and metallic glasses. On the other hand, the fine-grained Fe-10Cu materials behaved like coarse-grained iron in some respects, particularly by obeying the Hall-Petch equation with constants reasonably close to those of pure iron and by exhibiting low-temperature mechanical behavior which was very similar to that of steels. Transmission electron microscopy (TEM) studies found highly elongated grains within shear bands, indicating that shear banding occurred by a dislocation-based mechanism, at least at grain sizes above 100 nm. Similarities and differences between the fine-grained Fe-10Cu and metals, polymers, metallic glasses, radiation-damaged metals, and quench-damaged metals are discussed.

  8. Surface Chemistry in Nanoscale Materials

    Directory of Open Access Journals (Sweden)

    Alex V. Hamza

    2009-12-01

    Full Text Available Although surfaces or, more precisely, the surface atomic and electronic structure, determine the way materials interact with their environment, the influence of surface chemistry on the bulk of the material is generally considered to be small. However, in the case of high surface area materials such as nanoporous solids, surface properties can start to dominate the overall material behavior. This allows one to create new materials with physical and chemical properties that are no longer determined by the bulk material, but by their nanoscale architectures. Here, we discuss several examples, ranging from nanoporous gold to surface engineered carbon aerogels that demonstrate the tuneability of nanoporous solids for sustainable energy applications.

  9. [Recycle of contaminated scrap metal]: Task 1.3.2, Bulk solids feed system. Topical report, October 1993-- January 1996

    International Nuclear Information System (INIS)

    A critical requirement in DOE's efforts to recycle, reuse, and dispose of materials from its decontamination and decommissioning activities is the design of a robust system to process a wide variety of bulk solid feeds. The capability to process bulk solids will increase the range of materials and broaden the application of Catalytic Extraction Processing (CEP). The term bulk solids refers to materials that are more economically fed into the top of a molten metal bath than by submerged injection through a tuyere. Molten Metal Technology, Inc. (MMT) has characterized CEP's ability to process bulk solid feed materials and has achieved significant growth in the size of bulk solid particles compatible with Catalytic Extraction Processing. Parametric experimental studies using various feed materials representative of the components of various DOE waste streams have validated design models which establish the reactor operating range as a function of feed material, mass flow rate, and particle size. MMT is investigating the use of a slurry system for bulk solid addition as it is the most efficient means for injecting soils, sludges, and similar physical forms into a catalytic processing unit. MMT is continuing to evaluate condensed phase product removal systems and alternative energy addition sources to enhance the operating efficiency of bulk solids CEP units. A condensed phase product removal system capable of on-demand product removal has been successfully demonstrated. MMT is also investigating the use of a plasma arc torch to provide supplemental heating during bulk solids processing. This comprehensive approach to bulk solids processing is expected to further improve overall process efficiency prior to the deployment of CEP for the recycle, reuse, and disposal of materials from DOE decontamination and decommissioning Activities

  10. Thermal properties of Fe-based bulk metallic glasses

    Directory of Open Access Journals (Sweden)

    R. Nowosielski

    2012-12-01

    Full Text Available Purpose: The aim of paper is presentation of results bulk metallic glasses thermal properties such as temperatures typical for glassy transition and thermal conductivity. Design/methodology/approach: Investigations were realized for Fe36Co36B19.2Si4.8Nb4 samples with dimension 3 mm in diameter. Bulk test pieces were fabricated by copper mold casting method. Thermal analysis of master alloy (DTA and samples in as-cast state (DSC was realized. For amorphous structure confirmation the X-ray diffraction phase analysis (XRD was realized. Additionally scanning electron microscopy (SEM micrographs were performed in order to structure analysis. Thermal conductivity was determined by prototype measuring station.Findings: The XRD and SEM analysis confirmed amorphous structure of samples. Broad diffraction “halo” was observed for every testing piece. Fracture morphology is smooth with many “veins” on the surface, which are characteristic for glassy state. DTA analysis confirmed eutectic chemical composition of master alloy. Thermal conductivity measurements proved that both samples have comparable thermal conductivity.Practical implications: The FeCo-based bulk metallic glasses have attracted great interest for a variety application fields for example precision machinery materials, electric applications, structural materials, sporting goods, medical devices. Thermal conductivity is useful and important property for example computer simulation of temperature distribution and glass forming ability calculation.Originality/value: The obtained results confirm the utility of applied investigation methods in the thermal and structure analysis of examined amorphous alloys. Thermal conductivity was determined using the prototype measuring station, which is original issue of the paper. In future, the measuring station will be expanded for samples with different dimensions.

  11. Bulk and contact resistances of gas diffusion layers in proton exchange membrane fuel cells

    Science.gov (United States)

    Ye, Donghao; Gauthier, Eric; Benziger, Jay B.; Pan, Mu

    2014-06-01

    A multi-electrode probe is employed to distinguish the bulk and contact resistances of the catalyst layer (CL) and the gas diffusion layer (GDL) with the bipolar plate (BPP). Resistances are compared for Vulcan carbon catalyst layers (CL), carbon paper and carbon cloth GDL materials, and GDLs with microporous layers (MPL). The Vulcan carbon catalyst layer bulk resistance is 100 times greater than the bulk resistance of carbon paper GDL (Toray TG-H-120). Carbon cloth (CCWP) has bulk and contact resistances twice those of carbon paper. Compression of the GDL decreases the GDL contact resistance, but has little effect on the bulk resistance. Treatment of the GDL with polytetrafluoroethylene (PTFE) increases the contact resistance, but has little effect on the bulk resistance. A microporous layer (MPL) added to the GDL decreases the contact resistance, but has little effect on the bulk resistance. An equivalent circuit model shows that for channels less than 1 mm wide the contact resistance is the major source of electronic resistance and is about 10% of the total ohmic resistance associated with the membrane electrode assembly.

  12. Bulk-bronzied graphites for plasma-facing components in ITER (International Thermonuclear Experimental Reactor)

    Energy Technology Data Exchange (ETDEWEB)

    Hirooka, Y.; Conn, R.W.; Doerner, R.; Khandagle, M. (California Univ., Los Angeles, CA (USA). Inst. of Plasma and Fusion Research); Causey, R.; Wilson, K. (Sandia National Labs., Livermore, CA (USA)); Croessmann, D.; Whitley, J. (Sandia National Labs., Albuquerque, NM (USA)); Holland, D.; Smolik, G. (Idaho National Engineering Lab., Idaho Falls, ID (USA)); Matsuda, T.; Sogabe, T. (Toyo Tanso Co. Ltd., O

    1990-06-01

    Newly developed bulk-boronized graphites and boronized C-C composites with a total boron concentration ranging from 1 wt % to 30 wt % have been evaluated as plasma-facing component materials for the International Thermonuclear Experimental Reactor (ITER). Bulk-boronized graphites have been bombarded with high-flux deuterium plasmas at temperatures between 200 and 1600{degree}C. Plasma interaction induced erosion of bulk-boronized graphites is observed to be a factor of 2--3 smaller than that of pyrolytic graphite, in regimes of physical sputtering, chemical sputtering and radiation enhanced sublimation. Postbombardment thermal desorption spectroscopy indicates that bulk-boronized graphites enhance recombinative desorption of deuterium, which leads to a suppression of the formation of deuterocarbon due to chemical sputtering. The tritium inventory in graphite has been found to decrease by an order of magnitude due to 10 wt % bulk-boronization at temperatures above 1000{degree}C. The critical heat flux to induce cracking for bulk-boronized graphites has been found to be essentially the same as that for non-boronized graphites. Also, 10 wt % bulk-boronization of graphite hinders air oxidation nearly completely at 800{degree}C and reduces the steam oxidation rate by a factor of 2--3 at around 1100 and 1350{degree}C. 38 refs., 5 figs.

  13. Bulk-bronzied graphites for plasma-facing components in ITER [International Thermonuclear Experimental Reactor

    International Nuclear Information System (INIS)

    Newly developed bulk-boronized graphites and boronized C-C composites with a total boron concentration ranging from 1 wt % to 30 wt % have been evaluated as plasma-facing component materials for the International Thermonuclear Experimental Reactor (ITER). Bulk-boronized graphites have been bombarded with high-flux deuterium plasmas at temperatures between 200 and 1600 degree C. Plasma interaction induced erosion of bulk-boronized graphites is observed to be a factor of 2--3 smaller than that of pyrolytic graphite, in regimes of physical sputtering, chemical sputtering and radiation enhanced sublimation. Postbombardment thermal desorption spectroscopy indicates that bulk-boronized graphites enhance recombinative desorption of deuterium, which leads to a suppression of the formation of deuterocarbon due to chemical sputtering. The tritium inventory in graphite has been found to decrease by an order of magnitude due to 10 wt % bulk-boronization at temperatures above 1000 degree C. The critical heat flux to induce cracking for bulk-boronized graphites has been found to be essentially the same as that for non-boronized graphites. Also, 10 wt % bulk-boronization of graphite hinders air oxidation nearly completely at 800 degree C and reduces the steam oxidation rate by a factor of 2--3 at around 1100 and 1350 degree C. 38 refs., 5 figs

  14. THE OPTIMIZATION OF PLUSH YARNS BULKING PROCESS

    Directory of Open Access Journals (Sweden)

    VINEREANU Adam

    2014-05-01

    Full Text Available This paper presents the experiments that were conducted on the installation of continuous bulking and thermofixing “SUPERBA” type TVP-2S for optimization of the plush yarns bulking process. There were considered plush yarns Nm 6.5/2, made of the fibrous blend of 50% indigenous wool sort 41 and 50% PES. In the first stage, it performs a thermal treatment with a turboprevaporizer at a temperature lower than thermofixing temperature, at atmospheric pressure, such that the plush yarns - deposed in a freely state on a belt conveyor - are uniformly bulking and contracting. It was followed the mathematical modeling procedure, working with a factorial program, rotatable central composite type, and two independent variables. After analyzing the parameters that have a direct influence on the bulking degree, there were selected the pre-vaporization temperature (coded x1,oC and the velocity of belt inside pre-vaporizer (coded x 2, m/min. As for the dependent variable, it was chosen the plush yarn diameter (coded y, mm. There were found the coordinates of the optimal point, and then this pair of values was verified in practice. These coordinates are: x1optim= 90oC and x 2optim= 6.5 m/min. The conclusion is that the goal was accomplished: it was obtained a good cover degree f or double-plush carpets by reducing the number of tufts per unit surface.

  15. Determining the bulk strength of strata

    International Nuclear Information System (INIS)

    The bulk rock strength of strata is determined by logging a bore-hole with an instrument to obtain a neutron-neutron log of the hole and determining in conjunction with the lithology of the strata the strength by applying an inverse relation formula. (author)

  16. Realistic anomaly mediation with bulk gauge fields

    International Nuclear Information System (INIS)

    We present a simple general framework for realistic models of supersymmetry breaking driven by anomaly mediation. We consider a 5-dimensional 'brane universe' where the visible and hidden sectors are localized on different branes, and the standard model gauge bosons propagate in the bulk. In this framework there can be charged scalar messengers that have contact interactions with the hidden sector, either localized in the hidden sector or in the bulk. These scalars obtain soft masses that feed into visible sector scalar masses at two loop order via bulk gauge interactions. This contribution is automatically flavor-blind, and can be naturally positive. If the messengers are in the bulk this contribution is automatically the same order of magnitude as the anomaly mediated contribution, independent of the brane spacing. If the messengers are localized to a brane the two effects are of the same order for relatively small brane spacings. The gaugino masses and A terms are determined completely by anomaly mediation. In order for anomaly mediation to dominate over radion mediation the radion must be is stabilized in a manner that preserves supersymmetry, with supergravity effects included. We show that this occurs in simple models. We also show that the mu problem can be solved by the vacuum expectation value of a singlet in this framework. (author)

  17. Crevice chemistry estimation from bulk water chemistry

    International Nuclear Information System (INIS)

    Since the first PWR plant in Japan started commercial operation in 1970, 22 plants are running in Japan as of the end of 1994. The main purpose of secondary water chemistry control is to minimize the corrosion possibility of the secondary system equipment, especially steam generators (SG). To achieve this objective, much effort has been concentrated on improving secondary water chemistry control. As a result of this effort, the recent secondary water chemistry in Japanese plants is well maintained in every stage of operation. However, to ensure and improve the reliability of SG, it is necessary to control crevice environments, which are located at tube/tube support plate intersections and under the sludge pile on the tube sheet. According to recent crevice monitoring examination results, the concentration behavior impurities in SG bulk water at the crevice is different for each species, and SG bulk water and crevice chemical compositions are not always equal. From these results, to control the crevice chemistry, improving bulk water chemistry control methods and a new type of molar ratio control index is needed. This paper introduces a brief summary of a recent crevice chemistry evaluation technique and bulk water chemistry control method, which is employed for crevice chemistry control, based on crevice monitoring examination results

  18. A Stereoscopic Look into the Bulk

    CERN Document Server

    Czech, Bartlomiej; McCandlish, Samuel; Mosk, Benjamin; Sully, James

    2016-01-01

    We present the foundation for a holographic dictionary with depth perception. The dictionary consists of natural CFT operators whose duals are simple, diffeomorphism-invariant bulk operators. The CFT operators of interest are the "OPE blocks," contributions to the OPE from a single conformal family. In holographic theories, we show that the OPE blocks are dual at leading order in 1/N to integrals of effective bulk fields along geodesics or homogeneous minimal surfaces in anti-de Sitter space. One widely studied example of an OPE block is the modular Hamiltonian, which is dual to the fluctuation in the area of a minimal surface. Thus, our operators pave the way for generalizing the Ryu-Takayanagi relation to other bulk fields. Although the OPE blocks are non-local operators in the CFT, they admit a simple geometric description as fields in kinematic space--the space of pairs of CFT points. We develop the tools for constructing local bulk operators in terms of these non-local objects. The OPE blocks also allow ...

  19. Teaching Advanced SQL Skills: Text Bulk Loading

    Science.gov (United States)

    Olsen, David; Hauser, Karina

    2007-01-01

    Studies show that advanced database skills are important for students to be prepared for today's highly competitive job market. A common task for database administrators is to insert a large amount of data into a database. This paper illustrates how an up-to-date, advanced database topic, namely bulk insert, can be incorporated into a database…

  20. Longitudinal bulk a coustic mass sensor

    DEFF Research Database (Denmark)

    Hales, Jan Harry; Teva, Jordi; Boisen, Anja;

    2009-01-01

    Design, fabrication and characterization, in terms of mass sensitivity, is presented for a polycrystalline silicon longitudinal bulk acoustic cantilever. The device is operated in air at 51 MHz, resulting in a mass sensitivity of 100 HZ/fg (1 fg = 10{su−15 g). The initial characterization is cond...

  1. Production Equipment and Processes for Bulk Formed Micro Components

    Science.gov (United States)

    Paldan, N. A.; Arentoft, M.; Eriksen, R. S.

    2007-04-01

    Manufacturing techniques for production of small precise metallic parts has gained interest during recent years, an interest led by an industrial demand for components for integrated products like mobile phones, personal digital assistants (PDAs), mp3-players and in the future for spare parts for the human body. Micro components have also found several applications within the medical, audiological and dental industry, applications that impose increased demands for biocompatible and corrosion-resistant materials and cleanness. So far these micro components have mainly been manufactured by traditional machining techniques or chemical etching. However, these traditional machining and etching techniques are generally not well suited for mass production of advanced micro components, due to handling problems, waste of expensive material and long machining times. This calls for development of a novel production system that can meet the demands for high productivity, high reliability, low cost, while being environmental acceptable. Bulk metal forming meets these demands to a great extent, but the technology cannot directly be transferred to the micro scale. A flexible machine system for bulk micro forming has been developed and used to form a number of industrial micro parts in aluminium and silver, with ongoing work on forming of titanium. Manufacture of billets by cropping has been examined using a simple test rig and an automatic cropping device has been designed, manufactured and tested.

  2. Dense Shaped Refractory Products--Determination of Bulk Density, Apparent Porosity and True Porosity GB/T 2997-2000

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ 1 Scope This standard specifies the definition, principle, apparatus and materials, procedure, expression of results and test report of determination of bulk density, apparent porosity and true porosity of dense shaped refractory products.

  3. Comparison of radiation-induced helium blistering on thin films and bulk nickel specimens

    International Nuclear Information System (INIS)

    To compare helium blistering appearance on thin monocrystalline films and bulk nickel specimens, both specimen types were irradiated by He+ ions with 10 keV energy and current density of about 8 μA/cm at room temperature. It is found that on the films and bulk specimens blisters appear approximately at the same dose of about 5.5x1017 cm-2. In case of films blisters have an average diameter (0.31±0.05) μm and density (1.92±0.2)x108 cm-2 and an average diameter and density of blisters for bulk nickel constitute (0.33±0.08) μm and (1.76±0.2)x108 cm-2, accordingly. Conclusion of identity of the final stage of helium porosity development in the films and bulk materials, on which basisan assumption is said, that processes in the films and bulk specimens preceding the final stage of helium porosity development must proceed in the sae manner, has been drawn. In connection with this the conclusion of the possibility of thin film usage for investigating physical nature of phenomena related to helium porosity development and representation of results obtained during such investigations for the bulk material has been drawn as well

  4. Model calculations for evaluation of bulk- and grain boundary diffusion coefficients

    International Nuclear Information System (INIS)

    Model calculations are developed for evaluation of bulk- and grain boundary diffusion coefficients in polycrystalline media in the case of a semi-infinite diffusion source. The Matrix is assumed to be either quasi-homogeneous or to be composed of grain material and ''grain boundary-material''. Using Whipple's solution of the diffusion equation the flux of material from the grain boundaries into the grain is considered additionally. Examples are given to show the possibility to classify experimentally found diffusion profiles. (author)

  5. Mesoscopic discrete element modelling of cohesive powders for bulk handling applications

    OpenAIRE

    Thakur, Subhash Chandra

    2014-01-01

    Many powders and particulate solids are stored and handled in large quantities across various industries. These solids often encounter handling and storage difficulties that are caused by the material cohesion. The cohesive strength of a bulk material is a function of its past consolidation stress. For example, high material cohesive strength as a result from high storage stresses in a silo can cause ratholing problems during discharge. Therefore, it is essential to consider th...

  6. Relationship between single and bulk mechanical properties for zeolite ZSM5 spray-dried particles

    OpenAIRE

    Marigo, M.; Cairns, D. L.; Bowen, J; Ingram, A.; Stitt, E. H.

    2014-01-01

    In this work typical mechanical properties for a catalyst support material, ZSM5 (a spray-dried granular zeolite), have been measured in order to relate the bulk behaviour of the powder material to the single particle mechanical properties. Particle shape and size distribution of the powders, determined by laser diffraction and scanning electron microscopy (SEM), confirmed the spherical shape of the spray-dried particles. The excellent flowability of the material was assessed by typical metho...

  7. Finite element analysis and simulation of rheological properties of bulk molding compound (BMC)

    Science.gov (United States)

    Ergin, M. Fatih; Aydin, Ismail

    2013-12-01

    Bulk molding compound (BMC) is one of the important composite materials with various engineering applications. BMC is a thermoset plastic resin blend of various inert fillers, fiber reinforcements, catalysts, stabilizers and pigments that form a viscous, molding compound. Depending on the end-use application, bulk molding compounds are formulated to achieve close dimensional control, flame and scratch resistance, electrical insulation, corrosion and stain resistance, superior mechanical properties, low shrink and color stability. Its excellent flow characteristics, dielectric properties, and flame resistance make this thermoset material well-suited to a wide variety of applications requiring precision in detail and dimensions as well as high performance. When a BMC is used for these purposes, the rheological behavior and properties of the BMC is the main concern. In this paper, finite element analysis of rheological properties of bulk molding composite material was studied. For this purpose, standard samples of composite material were obtained by means of uniaxial hot pressing. 3 point flexural tests were then carried out by using a universal testing machine. Finite element analyses were then performed with defined material properties within a specific constitutive material behavior. Experimental and numerical results were then compared. Good correlation between the numerical simulation and the experimental results was obtained. It was expected with this study that effects of various process parameters and boundary conditions on the rheological behavior of bulk molding compounds could be determined by means of numerical analysis without detailed experimental work.

  8. Bulk sulfur (S) deposition in China

    Science.gov (United States)

    Liu, Lei; Zhang, Xiuying; Wang, Shanqian; Zhang, Wuting; Lu, Xuehe

    2016-06-01

    A systematic dataset of an observation network on a national scale has been organized to investigate the spatial distribution of bulk sulfur (S) deposition (Sdep) throughout China during 2000-2013, representing by far the most detailed data set to track the bulk sulfur deposition throughout China since 2000. Such a dataset is needed for ecosystem studies and for developing emission control policies. Bulk Sdep values showed great variations, ranging from 2.17 to 70.55 kg ha-1 y-1, with an average of 22.99 kg ha-1 y-1. The average rate of bulk Sdep located in East Coastal region (35.97 kg ha-1 y-1), Middle Yangtze region (57.90 kg ha-1 y-1), Middle Yellow River region (23.42 kg ha-1 y-1), North Coastal region (42.19 kg ha-1 y-1), Northeast region (34.28 kg ha-1 y-1), South Coastal region (36.97 kg S ha-1 y-1), Southwest region (33.85 kg ha-1 y-1) was 4.50, 7.24, 2.93, 5.28, 4.29, 4.63 and 4.24 times than that in Northwest region (7.99 kg ha-1 y-1). Bulk Sdep over China was mainly from fossil fuel combustion (76.96%), biomass burning (7.64%), crust (6.22%), aged sea salt (5.48%) and agriculture (3.68%). A systematic observation network on a national scale should be established to conduct a long-term monitoring atmospheric Sdep (including wet and dry deposition), based on exiting ecological stations administrated by different departments in China.

  9. Bulk characterization of pharmaceutical powders by low-pressure compression

    DEFF Research Database (Denmark)

    Sørensen, A.H.; Sonnergaard, Jørn; Hovgaard, L.

    2005-01-01

    Low-pressure compression of pharmaceutical powders using small amounts of sample (50 mg) was evaluated as an alternative to traditional bulk powder characterization by tapping volumetry. Material parameters were extrapolated directly from the compression data and by fitting with the Walker, the...... Kawakita, and the Log-Exp compression models. The compression-derived material parameters were compared to the poured and tapped density and the Compressibility Index determined by tapping. The repeatability of the compression-derived parameters was generally high, supporting their potential for...... characterization purposes. Significant correlation was demonstrated between several of the compression and tapping-derived parameters. The discriminative power of the low-pressure compression test was discussed using the compressed density at 0.2 MPa, correlated with the tapped density, and the relative Walker...

  10. Self-organized intermittent plastic flow in bulk metallic glasses

    International Nuclear Information System (INIS)

    Under stress, bulk metallic glasses irreversibly deform through shear banding processes that manifest as serrated flow behavior. These serration events exhibit a shock-and-aftershock, earthquake-like behavior. Statistical analysis shows that the shear avalanches can self-organize to a critical state (SOC). In analogy to the smooth macroscopic-scale crystalline plasticity that arises from the spatio-temporal averages of disruptive earthquake-like events at the nanometer scale, shear avalanches in glassy metals are another model system that can be used to study SOC behavior. With our understanding of SOC behavior, we further demonstrate how to enhance the plasticity of glassy (brittle) materials. It is expected that the findings can be extended to other glassy or brittle materials.

  11. Preparation and characterization of rare-earth bulks with controllable nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Song Xiaoyan [College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education, Beijing University of Technology, Beijing 100022 (China); Zhang Jiuxing [College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education, Beijing University of Technology, Beijing 100022 (China); Li Erdong [College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education, Beijing University of Technology, Beijing 100022 (China); Lu Nianduan [College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education, Beijing University of Technology, Beijing 100022 (China); Yin Fuxing [National Institute for Materials Science, Sengen 1-2-1, Tsukuba 305-0047 (Japan)

    2006-11-28

    The preparation and characterization of pure rare-earth-metal bulks with controllable nanostructures are reported in this paper. A novel 'oxygen-free' in situ synthesis technique that combines inert-gas condensation with spark plasma sintering (SPS) technology is proposed. Taking into account the special mechanisms of SPS consolidation and the scale effects of nanoparticles, we introduced practical procedures for preparing rare-earth bulks of amorphous, mixed amorphous and nanocrystals, and nanocrystalline microstructures, respectively. Compared with the conventional polycrystalline bulk, these nanostructured bulks exhibit substantially improved physical and mechanical properties. This technique enables comprehensive studies on the microstructures and properties of a large variety of nanostructured metallic materials that are highly reactive in the air.

  12. Preparation and characterization of rare-earth bulks with controllable nanostructures

    International Nuclear Information System (INIS)

    The preparation and characterization of pure rare-earth-metal bulks with controllable nanostructures are reported in this paper. A novel 'oxygen-free' in situ synthesis technique that combines inert-gas condensation with spark plasma sintering (SPS) technology is proposed. Taking into account the special mechanisms of SPS consolidation and the scale effects of nanoparticles, we introduced practical procedures for preparing rare-earth bulks of amorphous, mixed amorphous and nanocrystals, and nanocrystalline microstructures, respectively. Compared with the conventional polycrystalline bulk, these nanostructured bulks exhibit substantially improved physical and mechanical properties. This technique enables comprehensive studies on the microstructures and properties of a large variety of nanostructured metallic materials that are highly reactive in the air

  13. Neutron activation analysis of bulk samples from Chinese ancient porcelain to provenance research

    International Nuclear Information System (INIS)

    Neutron activation analysis (NAA) is an important technique to determine the provenance of ancient ceramics. The most common technique used for preparing ancient samples for NAA is to grind them into a powder and then encapsulate them before neutron irradiation. Unfortunately, ceramic materials are typically very hard making it a challenge to grind them into a powder. In this study we utilize bulk porcelain samples cut from ancient shards. The bulk samples are irradiated by neutrons alongside samples that have been conventionally ground into a powder. The NAA for both the bulk samples and powders are compared and shown to provide equivalent information regarding their chemical composition. Also, the multivariate statistical have been employed to the analysis data for check the consistency. The findings suggest that NAA results are less dependent on the state of the porcelain sample, and thus bulk samples cut from shards may be used to effectively determine their provenance. (author)

  14. Bulk and surface sensitivities of surface plasmon waveguides

    International Nuclear Information System (INIS)

    The potential of surface plasmon waveguides for bulk and surface (bio)chemical sensing was assessed theoretically, anticipating their use in an integrated optics sensor such as a Mach-Zehnder interferometer (MZI). The performance of a generic MZI implemented with attenuating waveguides was assessed initially, revealing that attenuating waveguides constrain the sensing length to an optimal length equal to the propagation length of the mode used. The MZI sensitivities for bulk and surface sensing were found to be proportional to the ratio of the waveguide sensitivity to its normalized attenuation: H=(∂neff/∂nc)/keff for bulk sensing and G=(∂neff/∂a)/keff for surface sensing. Maximizing H or G maximizes the corresponding MZI sensitivity and minimizes its detection limit, leading to preferred waveguide designs and operating wavelengths. The propagation constant, the sensitivities, and the H and G parameters were then determined for the surface plasmon in the single interface, the sb mode in the metal-insulator-metal (MIM) waveguide and the sb mode in three variants of the insulator-metal-insulator (IMI) waveguide, as a function of dimensions, for wavelengths spanning 600≤λ0≤1600 nm, assuming Au and H2O as the materials and adlayers representative of biochemical matter. The principal findings are: (i) the surface sensitivity in the thin MIM can be 100x larger than in the single interface, whereas that in the thin IMI is up to 5x smaller; (ii) the bulk sensitivity in the thin MIM can be 3x larger than in the single interface, whereas that in the IMI is slightly smaller; (iii) G in the thin MIM can be 3x larger than in the single interface, whereas G in the IMI is about 10x larger; and (iv) H in the thin MIM can be 10x smaller than in the single interface, whereas H in the thin IMI is about 10x larger. The IMI and the MIM both offer an improvement in sensitivity and detection limit for surface sensing over the single interface in an integrated MZI (or

  15. 27 CFR 1.90 - Distilled spirits in bulk.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Distilled spirits in bulk..., NONINDUSTRIAL USE OF DISTILLED SPIRITS AND WINE, BULK SALES AND BOTTLING OF DISTILLED SPIRITS Bulk Sales and Bottling of Distilled Spirits Warehouse Receipts § 1.90 Distilled spirits in bulk. By the terms of the...

  16. Dynamic Plastic Deformation (DPD): A Novel Technique for Synthesizing Bulk Nanostructured Metals

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    While some superior properties of nanostructured materials (with structural scales below 100 nm) have attracted numerous interests of material scientists, technique development for synthesizing nanostructured metals and alloys in 3-dimensional (3D) bulk forms is still challenging despite of extensive investigations over decades.Here we report a novel synthesis technique for bulk nanostructured metals based on plastic deformation at high Zener-Hollomon parameters (high strain rates or low temperatures), i.e., dynamic plastic deformation (DPD).The basic concept behind this approach will be addressed together with a few examples to demonstrate the capability and characteristics of this method. Perspectives and future developments of this technique will be highlighted.

  17. Bulk hydrogen analysis, using neutrons. Final report of the first research co-ordination meeting

    International Nuclear Information System (INIS)

    There are many situations when hydrogen is required to be measured in a bulk medium. For this reason neutrons are used due to their high penetrating power in dense material. In addition, the mass attenuation coefficient for neutrons in hydrogen is significantly larger than for all other elements, meaning that neutrons have a higher probability of interacting with hydrogen than with other elements in the sample matrix. This CRP was recommended for further development of the techniques and new applications in the following areas: Fast Neutron/Gamma Transmission Technique; Digital Neutron Imaging; Hydrogen Detection by Epithermal Neutrons; Microscopic Behaviour of Hydrogen in Bulk Materials

  18. Achieving large linear elasticity and high strength in bulk nanocompsite via synergistic effect

    OpenAIRE

    Shijie Hao; Lishan Cui; Fangmin Guo; Yinong Liu; Xiaobin Shi; Daqiang Jiang; Dennis E. Brown; Yang Ren

    2015-01-01

    Elastic strain in bulk metallic materials is usually limited to only a fraction of 1%. Developing bulk metallic materials showing large linear elasticity and high strength has proven to be difficult. Here, based on the synergistic effect between nanowires and orientated martensite NiTi shape memory alloy, we developed an in-situ Nb nanowires -orientated martensitic NiTi matrix composite showing an ultra-large linear elastic strain of 4% and an ultrahigh yield strength of 1.8 GPa. This materia...

  19. Bulk solitary waves in elastic solids

    Science.gov (United States)

    Samsonov, A. M.; Dreiden, G. V.; Semenova, I. V.; Shvartz, A. G.

    2015-10-01

    A short and object oriented conspectus of bulk solitary wave theory, numerical simulations and real experiments in condensed matter is given. Upon a brief description of the soliton history and development we focus on bulk solitary waves of strain, also known as waves of density and, sometimes, as elastic and/or acoustic solitons. We consider the problem of nonlinear bulk wave generation and detection in basic structural elements, rods, plates and shells, that are exhaustively studied and widely used in physics and engineering. However, it is mostly valid for linear elasticity, whereas dynamic nonlinear theory of these elements is still far from being completed. In order to show how the nonlinear waves can be used in various applications, we studied the solitary elastic wave propagation along lengthy wave guides, and remarkably small attenuation of elastic solitons was proven in physical experiments. Both theory and generation for strain soliton in a shell, however, remained unsolved problems until recently, and we consider in more details the nonlinear bulk wave propagation in a shell. We studied an axially symmetric deformation of an infinite nonlinearly elastic cylindrical shell without torsion. The problem for bulk longitudinal waves is shown to be reducible to the one equation, if a relation between transversal displacement and the longitudinal strain is found. It is found that both the 1+1D and even the 1+2D problems for long travelling waves in nonlinear solids can be reduced to the Weierstrass equation for elliptic functions, which provide the solitary wave solutions as appropriate limits. We show that the accuracy in the boundary conditions on free lateral surfaces is of crucial importance for solution, derive the only equation for longitudinal nonlinear strain wave and show, that the equation has, amongst others, a bidirectional solitary wave solution, which lead us to successful physical experiments. We observed first the compression solitary wave in the

  20. Performance of bulk SiC radiation detectors

    CERN Document Server

    Cunningham, W; Lamb, G; Scott, J; Mathieson, K; Roy, P; Bates, R; Thornton, P; Smith, K M; Cusco, R; Glaser, M; Rahman, M

    2002-01-01

    SiC is a wide-gap material with excellent electrical and physical properties that may make it an important material for some future electronic devices. The most important possible applications of SiC are in hostile environments, such as in car/jet engines, within nuclear reactors, or in outer space. Another area where the material properties, most notably radiation hardness, would be valuable is in the inner tracking detectors of particle physics experiments. Here, we describe the performance of SiC diodes irradiated in the 24 GeV proton beam at CERN. Schottky measurements have been used to probe the irradiated material for changes in I-V characteristics. Other methods, borrowed from III-V research, used to study the irradiated surface include atomic force microscope scans and Raman spectroscopy. These have been used to observe the damage to the materials surface and internal lattice structure. We have also characterised the detection capabilities of bulk semi-insulating SiC for alpha radiation. By measuring ...

  1. Melt-growth bulk superconductors and application to an axial-gap-type rotating machine

    Science.gov (United States)

    Zhang, Yufeng; Zhou, Difan; Ida, Tetsuya; Miki, Motohiro; Izumi, Mitsuru

    2016-04-01

    The present manuscript addresses key issues in the course of our study of materials processing of bulk high-temperature superconductors, trapped flux and its application to a prototype axial-gap-type rotating machine. The TUMSAT group has conducted a series of studies since 2003 on the growth of GdBa2Cu3O7-δ bulk material and its application in a compact low-speed high-torque rotating machine. In the stage of material growth, gaining the advantage of a large motive torque density requires large integrated flux in the motor/generators. A large grain surface might be required with sophisticated techniques for the melt-growth texture in the bulk with optimal flux pinning. In the second stage, the in situ magnetization procedure for bulk superconductors in the applied machine is a crucial part of the technology. Pulsed current excitation by using an armature copper winding has magnetized field pole bulks on the rotor. The axial-gap flux synchronous machine studied in the past decade is a condensed technology and indicates that further scientific development is required for a future compact machine to be superior to conventional ones in accordance with the cryogenic periphery and flux stabilization.

  2. Evaluation of Radiopacity of Bulk-fill Flowable Composites Using Digital Radiography.

    Science.gov (United States)

    Tarcin, B; Gumru, B; Peker, S; Ovecoglu, H S

    2016-01-01

    New flowable composites that may be bulk-filled in layers up to 4 mm are indicated as a base beneath posterior composite restorations. Sufficient radiopacity is one of the several important requirements such materials should meet. The aim of this study was to evaluate the radiopacity of bulk-fill flowable composites and to provide a comparison with conventional flowable composites using digital imaging. Ten standard specimens (5 mm in diameter, 1 mm in thickness) were prepared from each of four different bulk-fill flowable composites and nine different conventional flowable composites. Radiographs of the specimens were taken together with 1-mm-thick tooth slices and an aluminum step wedge using a digital imaging system. For the radiographic exposures, a storage phosphor plate and a dental x-ray unit at 70 kVp and 8 mA were used. The object-to-focus distance was 30 cm, and the exposure time was 0.2 seconds. The gray values of the materials were measured using the histogram function of the software available with the system, and radiopacity was calculated as the equivalent thickness of aluminum. The data were analyzed statistically (p SDR (Dentsply DeTrey) ≥ Filtek Bulk Fill (3M ESPE). To conclude, the bulk-fill flowable restorative materials, which were tested in this study using digital radiography, met the minimum standard of radiopacity specified by the International Standards Organization. PMID:27045286

  3. Premelting at Defects Within Bulk Colloidal Crystals

    Science.gov (United States)

    Alsayed, A. M.; Islam, M. F.; Zhang, J.; Collings, P. J.; Yodh, A. G.

    2005-08-01

    Premelting is the localized loss of crystalline order at surfaces and defects at temperatures below the bulk melting transition. It can be thought of as the nucleation of the melting process. Premelting has been observed at the surfaces of crystals but not within. We report observations of premelting at grain boundaries and dislocations within bulk colloidal crystals using real-time video microscopy. The crystals are equilibrium close-packed, three-dimensional colloidal structures made from thermally responsive microgel spheres. Particle tracking reveals increased disorder in crystalline regions bordering defects, the amount of which depends on the type of defect, distance from the defect, and particle volume fraction. Our observations suggest that interfacial free energy is the crucial parameter for premelting in colloidal and atomic-scale crystals.

  4. Fully antisymmetrised dynamics for bulk fermion systems

    International Nuclear Information System (INIS)

    The neutron star's crust and mantel are typical examples of non-uniform bulk systems with spacial localisations. When modelling such systems at low temperatures, as is the case in the crust, one has to work with antisymmetrised many-body states to get the correct fermion behaviour. Fermionic molecular dynamics, which works with an antisymmetrised product of localised wave packets, should be an appropriate choice. Implementing periodic boundary conditions into the fermionic molecular dynamics formalism would allow the study of the neutron star's crust as a bulk quantum system. Unfortunately, the antisymmetrisation is a non-local entanglement which reaches far out of the periodically repeated unit cell. In this proceeding, we give a brief overview how periodic boundary conditions and fermionic molecular dynamics can be combined without truncating the long-range many-body correlation induced by the antisymmetry of the many-body state.

  5. NPP bulk equipment dismantling problems and experience

    International Nuclear Information System (INIS)

    NPP bulk equipment dismantling problems and experience are summarized. 'ECOMET-S' JSC is shown as one of the companies which are able to make NPPs industrial sites free from stored bulk equipment with its further utilization. 'ECOMET-S' JSC is the Russian Federation sole specialized metallic LLW (MLLW) treatment and utilization facility. Company's main objectives are waste predisposal volume reduction and treatment for the unrestricted release as a scrap. Leningrad NPP decommissioned main pumps and moisture separators/steam super heaters dismantling results are presented. Prospective fragmentation technologies (diamond and electro-erosive cutting) testing results are described. The electro-erosive cutting machine designed by 'ECOMET-S' JSC is presented. The fragmentation technologies implementation plans for nuclear industry are presented too. (author)

  6. Bulk viscous cosmology with causal transport theory

    International Nuclear Information System (INIS)

    We consider cosmological scenarios originating from a single imperfect fluid with bulk viscosity and apply Eckart's and both the full and the truncated Müller-Israel-Stewart's theories as descriptions of the non-equilibrium processes. Our principal objective is to investigate if the dynamical properties of Dark Matter and Dark Energy can be described by a single viscous fluid and how such description changes when a causal theory (Müller-Israel-Stewart's, both in its full and truncated forms) is taken into account instead of Eckart's non-causal one. To this purpose, we find numerical solutions for the gravitational potential and compare its behaviour with the corresponding ΛCDM case. Eckart's and the full causal theory seem to be disfavoured, whereas the truncated theory leads to results similar to those of the ΛCDM model for a bulk viscous speed in the interval 10−11 || cb2 ∼−8

  7. Bulk band gaps in divalent hexaborides

    Energy Technology Data Exchange (ETDEWEB)

    Denlinger, Jonathan; Clack, Jules A.; Allen, James W.; Gweon, Gey-Hong; Poirier, Derek M.; Olson, Cliff G.; Sarrao, John L.; Bianchi, Andrea D.; Fisk, Zachary

    2002-08-01

    Complementary angle-resolved photoemission and bulk-sensitive k-resolved resonant inelastic x-ray scattering of divalent hexaborides reveal a >1 eV X-point gap between the valence and conduction bands, in contradiction to the band overlap assumed in several models of their novel ferromagnetism. This semiconducting gap implies that carriers detected in transport measurements arise from defects, and the measured location of the bulk Fermi level at the bottom of the conduction band implicates boron vacancies as the origin of the excess electrons. The measured band structure and X-point gap in CaB6 additionally provide a stringent test case for proper inclusion of many-body effects in quasi-particle band calculations.

  8. Surface-Bulk Vibrational Correlation Spectroscopy.

    Science.gov (United States)

    Roy, Sandra; Covert, Paul A; Jarisz, Tasha A; Chan, Chantelle; Hore, Dennis K

    2016-05-01

    Homo- and heterospectral correlation analysis are powerful methods for investigating the effects of external influences on the spectra acquired using distinct and complementary techniques. Nonlinear vibrational spectroscopy is a selective and sensitive probe of surface structure changes, as bulk molecules are excluded on the basis of symmetry. However, as a result of this exquisite specificity, it is blind to changes that may be occurring in the solution. We demonstrate that correlation analysis between surface-specific techniques and bulk probes such as infrared absorption or Raman scattering may be used to reveal additional details of the adsorption process. Using the adsorption of water and ethanol binary mixtures as an example, we illustrate that this provides support for a competitive binding model and adds new insight into a dimer-to-bilayer transition proposed from previous experiments and simulations. PMID:27058265

  9. Nuclear Matter Bulk Parameter Scales and Correlations

    International Nuclear Information System (INIS)

    We study the arising of correlations among some isovector bulk parameters in nonrelativistic and relativistic hadronic mean-field models. For the former, we investigate correlations in the nonrelativistic (NR) limit of relativistic point-coupling models. We provide analytical correlations, for the NR limit model, between the symmetry energy and its derivatives, namely, the symmetry energy slope, curvature, skewness and fourth order derivative, discussing the conditions in which they are linear ones. We also show that some correlations presented in the NR limit model are reproduced for relativistic models presenting cubic and quartic self-interactions in its scalar field. As a direct application of such linear correlations, we remark its association with possible crossing points in the density dependence of the linearly correlated bulk parameter. (author)

  10. Brane plus Bulk Supersymmetry in Ten Dimensions

    CERN Document Server

    Bergshoeff, E A; Ortín, Tomas; Roest, D; Van Proeyen, A

    2001-01-01

    We discuss a generalized form of IIA/IIB supergravity depending on all R-R potentials C^(p) (p=0,1,...,9) as the effective field theory of Type IIA/IIB superstring theory. For the IIA case we explicitly break this R-R democracy to either p=5 which allows us to write a new bulk action that can be coupled to N=1 supersymmetric brane actions. The case of 8-branes is studied in detail using the new bulk & brane action. The supersymmetric negative tension branes without matter excitations can be viewed as orientifolds in the effective action. These D8-branes and O8-planes are fundamental in Type I' string theory. A BPS 8-brane solution is given which satisfies the jump conditions on the wall. As an application of our results we derive a quantization of the mass parameter and the cosmological constant in string units.

  11. Melt Grown ZnO Bulk Crystals

    OpenAIRE

    Schulz, Detlev; Ganschow, Steffen; Klimm, Detlef

    2009-01-01

    Bulk crystals of zinc oxide can be grown from the melt by a Bridgman technique under pressure. This new technology using an iridium crucible shows the potential to yield large single crystals of good crystalline perfection. Crystals with diameters up to 33 mm and a length of up to 50 mm have been demonstrated. The impurity content can be strongly reduced by using the crucibles repeatedly.

  12. Oscillatory Dynamical Switching System of Bulk Ferroelectrics

    OpenAIRE

    M. N.A. Halif; S. Daud; Junaidah Osman

    2005-01-01

    This study gives a detailed account of calculation of the bulk ferroelectric (FE) oscillatory dynamical system switching to first and second-order phase transition, respectively. All the formalism is delineated in the framework of Landau free-energy expansion and Landau-Khalatnikov (LK) equation of motion where the effect of external energy may affray FE atoms similar to the spring damped oscillatory system. Here we scrutinized the switching properties from free-energy expansion and hysteresi...

  13. Effective Pure States for Bulk Quantum Computation

    OpenAIRE

    Knill, Emanuel; Chuang, Isaac; Laflamme, Raymond

    1997-01-01

    In bulk quantum computation one can manipulate a large number of indistinguishable quantum computers by parallel unitary operations and measure expectation values of certain observables with limited sensitivity. The initial state of each computer in the ensemble is known but not pure. Methods for obtaining effective pure input states by a series of manipulations have been described by Gershenfeld and Chuang (logical labeling) and Cory et al. (spatial averaging) for the case of quantum computa...

  14. Superconducting RF cavities film of bulk

    CERN Document Server

    Darriulat, Pierre

    1999-01-01

    The successful operation of LEP2 has demonstrated the feasibility of using on a large scale copper accelerating cavities coated with a thin superconducting niobium film. Yet other existing or planned installations such as CEBAF and TESLA, rely instead on the bulk niobium technology. The reason is a wide spread belief that the film technology would suffer from fundamental limitations preventing high gradients to be reached...

  15. Depleted Bulk Heterojunction Colloidal Quantum Dot Photovoltaics

    KAUST Repository

    Barkhouse, D. Aaron R.

    2011-05-26

    The first solution-processed depleted bulk heterojunction colloidal quantum dot solar cells are presented. The architecture allows for high absorption with full depletion, thereby breaking the photon absorption/carrier extraction compromise inherent in planar devices. A record power conversion of 5.5% under simulated AM 1.5 illumination conditions is reported. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Statistical Determination of Bulk Flow Motions

    CERN Document Server

    Song, Yong-Seon; Nichol, Robert C; Miller, Christopher J

    2010-01-01

    We present here a new parameterization for the bulk motions of galaxies and clusters (in the linear regime) that can be measured statistically from the shape and amplitude of the two-dimensional two-point correlation function. We further propose the one-dimensional velocity dispersion (v_p) of the bulk flow as a complementary measure of redshift-space distortions, which is model-independent and not dependent on the normalisation method. As a demonstration, we have applied our new methodology to the C4 cluster catalogue constructed from Data Release Three (DR3) of the Sloan Digital Sky Survey. We find v_p=270^{+433}km/s (also consistent with v_p=0) for this cluster sample (at z=0.1), which is in agreement with that predicted for a WMAP5-normalised LCDM model (i.e., v_p(LCDM=203km/s). This measurement does not lend support to recent claims of excessive bulk motions (\\simeq1000 km/s) which appear in conflict with LCDM, although our large statistical error cannot rule them out. From the measured coherent evolutio...

  17. Superconducting State Parameters of Bulk Amorphous Alloys

    Directory of Open Access Journals (Sweden)

    Aditya M. Vora

    2012-12-01

    Full Text Available Well recognized empty core (EMC pseudopotential of Ashcroft is used to investigate the superconducting state parameters viz; electron-phonon coupling strength λ, Coulomb pseudopotential μ*, transition temperature TC, isotope effect exponent α and effective interaction strength NOV of some (Ni33Zr671 – xVx (x = 0, 0.05, 0.1, 0.15 bulk amorphous alloys. We have incorporated five different types of local field correction functions, proposed by Hartree (H, Taylor (T, Ichimaru-Utsumi (IU, Farid et al. (F and Sarkar et al. (S to show the effect of exchange and correlation on the aforesaid properties. Very strong influence of the various exchange and correlation functions is concluded from the present study. The TC obtained from Sarkar et al. (S local field correction function are found an excellent agreement with available theoretical data. Quadratic TC equation has been proposed, which provide successfully the TC values of bulk amorphous alloys under consideration. Also, the present results are found in qualitative agreement with other such earlier reported data, which confirms the superconducting phase in the s bulk amorphous alloys.

  18. Bulk viscous cosmology in early Universe

    Indian Academy of Sciences (India)

    C P Singh

    2008-07-01

    The effect of bulk viscosity on the early evolution of Universe for a spatially homogeneous and isotropic Robertson-Walker model is considered. Einstein's field equations are solved by using `gamma-law' equation of state = ( - 1)ρ, where the adiabatic parameter gamma () depends on the scale factor of the model. The `gamma' function is defined in such a way that it describes a unified solution of early evolution of the Universe for inflationary and radiation-dominated phases. The fluid has only bulk viscous term and the coefficient of bulk viscosity is taken to be proportional to some power function of the energy density. The complete general solutions have been given through three cases. For flat space, power-law as well as exponential solutions are found. The problem of how the introduction of viscosity affects the appearance of singularity, is briefly discussed in particular solutions. The deceleration parameter has a freedom to vary with the scale factor of the model, which describes the accelerating expansion of the Universe.

  19. DEMONSTRATION BULK VITRIFICATION SYSTEM (DBVS) EXTERNAL REVIEW

    International Nuclear Information System (INIS)

    The Hanford mission to retrieve and immobilize 53 million gallons of radioactive waste from 177 underground storage tanks will be accomplished using a combination of processing by the waste treatment plant currently under construction, and a supplemental treatment that would process low-activity waste. Under consideration for this treatment is bulk vitrification, a versatile joule-heated melter technology which could be deployed in the tank farms. The Department proposes to demonstrate this technology under a Research, Development and Demonstration (RD and D) permit issued by the Washington State Department of Ecology using both non-radioactive simulant and blends of actual tank waste. From the demonstration program, data would be obtained on cost and technical performance to enable a decision on the potential use of bulk vitrification as the supplemental treatment technology for Hanford. An independent review by sixteen subject matter experts was conducted to assure that the technical basis of the demonstration facility design would be adequate to meet the objectives of the Demonstration Bulk Vitrification System (DBVS) program. This review explored all aspects of the program, including flowsheet chemistry, project risk, vitrification, equipment design and nuclear safety, and was carried out at a time when issues can be identified and corrected. This paper describes the mission need, review approach, technical recommendations and follow-on activities for the DBVS program

  20. Multiphase composites with extremal bulk modulus

    DEFF Research Database (Denmark)

    Gibiansky, L. V.; Sigmund, Ole

    2000-01-01

    This paper is devoted to the analytical and numerical study of isotropic elastic composites made of three or more isotropic phases. The ranges of their effective bulk and shear moduli are restricted by the Hashin-Shtrikman-Walpole (HSW) bounds. For two-phase composites, these bounds are attainabl...... isotropic three-dimensional three-phase composites with cylindrical inclusions of arbitrary cross-sections (plane strain problem) or transversely isotropic thin plates (plane stress or bending of plates problems). (C) 2000 Elsevier Science Ltd. All rights reserved.......This paper is devoted to the analytical and numerical study of isotropic elastic composites made of three or more isotropic phases. The ranges of their effective bulk and shear moduli are restricted by the Hashin-Shtrikman-Walpole (HSW) bounds. For two-phase composites, these bounds are attainable......, that is, there exist composites with extreme bulk and shear moduli. For multiphase composites, they may or may not be attainable depending on phase moduli and volume fractions. Sufficient conditions of attainability of the bounds and various previously known and new types of optimal composites are...

  1. Bulk Comptonization by turbulence in accretion discs

    Science.gov (United States)

    Kaufman, J.; Blaes, O. M.

    2016-06-01

    Radiation pressure dominated accretion discs around compact objects may have turbulent velocities that greatly exceed the electron thermal velocities within the disc. Bulk Comptonization by the turbulence may therefore dominate over thermal Comptonization in determining the emergent spectrum. Bulk Comptonization by divergenceless turbulence is due to radiation viscous dissipation only. It can be treated as thermal Comptonization by solving the Kompaneets equation with an equivalent `wave' temperature, which is a weighted sum over the power present at each scale in the turbulent cascade. Bulk Comptonization by turbulence with non-zero divergence is due to both pressure work and radiation viscous dissipation. Pressure work has negligible effect on photon spectra in the limit of optically thin turbulence, and in this limit radiation viscous dissipation alone can be treated as thermal Comptonization with a temperature equivalent to the full turbulent power. In the limit of extremely optically thick turbulence, radiation viscous dissipation is suppressed, and the evolution of local photon spectra can be understood in terms of compression and expansion of the strongly coupled photon and gas fluids. We discuss the consequences of these effects for self-consistently resolving and interpreting turbulent Comptonization in spectral calculations in radiation magnetohydrodynamic simulations of high luminosity accretion flows.

  2. Three-dimensional microstructural characterization of bulk plutonium and uranium metals using focused ion beam technique

    Science.gov (United States)

    Chung, Brandon W.; Erler, Robert G.; Teslich, Nick E.

    2016-05-01

    Nuclear forensics requires accurate quantification of discriminating microstructural characteristics of the bulk nuclear material to identify its process history and provenance. Conventional metallographic preparation techniques for bulk plutonium (Pu) and uranium (U) metals are limited to providing information in two-dimension (2D) and do not allow for obtaining depth profile of the material. In this contribution, use of dual-beam focused ion-beam/scanning electron microscopy (FIB-SEM) to investigate the internal microstructure of bulk Pu and U metals is demonstrated. Our results demonstrate that the dual-beam methodology optimally elucidate microstructural features without preparation artifacts, and the three-dimensional (3D) characterization of inner microstructures can reveal salient microstructural features that cannot be observed from conventional metallographic techniques. Examples are shown to demonstrate the benefit of FIB-SEM in improving microstructural characterization of microscopic inclusions, particularly with respect to nuclear forensics.

  3. Development of fabrication technique of bulk high superconductor

    International Nuclear Information System (INIS)

    In order to realize the commercial application of HTSC materials, it is necessary to develop the fabrication process of high Tc oxide superconductor materials with desired shape and for practical application and high critical current density as well as good mechanical strength which critical current density as well as good mechanical strength which can withstand high lorenz force generated at high magnetic field. Much studies have been concentrated to develop the fabrication technique for high critical current density but still there are a lot of gap which should be overcome for large scale application of HTSC materials at liquid nitrogen temperature. Recently some new fabrication techniques have been developed for YBCO bulk superconductor with high mechanical strength and critical current density. In this project, plastic extrusion and melt process techniques were studied. The components materials for the current lead and the flywheel application were fabricated and their characteristics were investigated from the view point of microstructure and phase formation during heat treatment process. (author). 64 refs., 59 figs

  4. Yielding and its adaptability of several promising bulk cocoa clones

    Directory of Open Access Journals (Sweden)

    Dedy Suhendi

    2005-05-01

    Full Text Available Yielding and its adaptability are considered to be an important criteria for clones recommendation. An experiment to evaluate yield and its adaptability of several promising bulk cocoa clones has been executed during 1996—2003 in three locations having different altitude and type of climate, consisted of Jatirono(450 m asl., B type of climate, Kalisepanjang (275 m asl., C type of climate and Kalitelepak (145 m asl., B type of climate. Randomized completely block design (RCBD was used in each location with 14 promising clones and four replications. Recommended clones of ICS 60 and GC 7 were used as standard. The promising clones were originated from mother trees selection with the main criteria of yield. Observations were conducted on yield and its components as well as bean characteristics. Determination of adaptability of each clone by using yield performance and its stability. Statistical analysis was done by using combined analysis. The results showed that KW 30 and KW 48 perform higher yield (2.3 ton/ha than that of standard clone (1.7 ton/ha as well as consistant yield stability between location and over years. There for, the two clones performed good adaptability. KW 30 and KW 48 also perform good yield components, and high percentage of fat content i.e 55%. So, those clones are potential to be recommended for commercial planting materials. Key words : bulk cocoa, yield, clone, stability, adaptability.

  5. Processing of bulk Bi-2223 high-temperature superconductor

    Directory of Open Access Journals (Sweden)

    Alexander Polasek

    2005-12-01

    Full Text Available The Bi2Sr2Ca2Cu3 O10+x (Bi-2223 is one of the main high temperature superconductors for applications. One of these applications is the Superconductor Fault Current Limiter (SCFCL, which is a very promising high temperature superconducting device. SCFCL's can be improved by using bulk superconductors with high critical currents, which requires a sufficiently dense and textured material. In the present work, a process for improving the microstructure of Bi-2223 bulk samples is investigated. Pressed precursor blocks are processed by sintering with a further partial melting step, in order to enhance the Bi-2223 grain texture and to healing cracks induced by pressing. In order to improve the microstructure, the precursor is mixed with silver powder before pressing. Samples with and without silver powder have been studied, with the aim of investigating the influence of silver on the microstructure evolution. The phase contents and the microstructure obtained have been analyzed through XRD and SEM/EDS. The electromagnetic characterization has been performed by Magnetic Susceptibility Analysis. We present and discuss the process and the properties of the superconducting blocks. High fractions of textured Bi-2223 grains have been obtained.

  6. Digestibility and bulking effect of ispaghula husks in healthy humans.

    Science.gov (United States)

    Marteau, P; Flourié, B; Cherbut, C; Corrèze, J L; Pellier, P; Seylaz, J; Rambaud, J C

    1994-12-01

    The digestibility of ispaghula, a mucilage from Plantago ovata composed mainly of arabinoxylans, and its faecal bulking effect were studied in seven healthy volunteers who ingested a low fibre controlled diet plus either placebo or 18 g/day of ispaghula for two 15 day periods. Whole gut transit time and gas excretion in breath and flatus were not different during the periods of ispaghula and placebo ingestion. Faecal wet and dry weights rose significantly, however, during ispaghula ingestion. Faecal short chain fatty acid concentrations and the molar proportions of propionic and acetic acids also increased. Most of the ispaghula had reached the caecum four hours after ingestion in an intact highly polymerised form. During ispaghula ingestion, the increase in the faecal output of neutral sugars was accounted for by the faecal excretion of arabinose and xylose in an intact highly polymerised form; the apparent digestibilities of these sugars were 24 (11) and 53% (6) respectively (mean (SEM)). In conclusion, ispaghula is more resistant to fermentation than previously reported in humans, and its bulking effect largely results from intact material. PMID:7829013

  7. X-Ray Nanoscopy of a Bulk Heterojunction

    Science.gov (United States)

    Skjønsfjell, Eirik Torbjørn Bakken; Van den Brande, Niko; Chavez Panduro, Elvia Anabela; Claessens, Raf; Guizar-Sicairos, Manuel; Van Mele, Bruno; Breiby, Dag Werner

    2016-01-01

    Optimizing the morphology of bulk heterojunctions is known to significantly improve the photovoltaic performance of organic solar cells, but available quantitative imaging techniques are few and have severe limitations. We demonstrate X-ray ptychographic coherent diffractive imaging applied to all-organic blends. Specifically, the phase-separated morphology in bulk heterojunction photoactive layers for organic solar cells, prepared from a 50:50 blend of poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) and thermally treated for different annealing times is imaged to high resolution. Moreover, using a fast-scanning calorimetry chip setup, the nano-morphological changes caused by repeated thermal annealing applied to the same sample could be monitored. X-ray ptychography resolves to better than 100 nm the phase-segregated domains of electron donor and electron acceptor materials over a large field of view within the active layers. The quantitative phase contrast images further allow us to estimate the local volume fraction of PCBM across the photovoltaically active layers. The volume fraction gradient for different regions provides insight on the PCBM diffusion across the depletion zone surrounding PCBM aggregates. Phase contrast X-ray microscopy is under rapid development, and the results presented here are promising for future studies of organic-organic blends, also under in situ conditions, e.g., for monitoring the structural stability during UV-Vis irradiation. PMID:27367796

  8. X-Ray Nanoscopy of a Bulk Heterojunction.

    Directory of Open Access Journals (Sweden)

    Nilesh Patil

    Full Text Available Optimizing the morphology of bulk heterojunctions is known to significantly improve the photovoltaic performance of organic solar cells, but available quantitative imaging techniques are few and have severe limitations. We demonstrate X-ray ptychographic coherent diffractive imaging applied to all-organic blends. Specifically, the phase-separated morphology in bulk heterojunction photoactive layers for organic solar cells, prepared from a 50:50 blend of poly(3-hexylthiophene (P3HT and phenyl-C61-butyric acid methyl ester (PCBM and thermally treated for different annealing times is imaged to high resolution. Moreover, using a fast-scanning calorimetry chip setup, the nano-morphological changes caused by repeated thermal annealing applied to the same sample could be monitored. X-ray ptychography resolves to better than 100 nm the phase-segregated domains of electron donor and electron acceptor materials over a large field of view within the active layers. The quantitative phase contrast images further allow us to estimate the local volume fraction of PCBM across the photovoltaically active layers. The volume fraction gradient for different regions provides insight on the PCBM diffusion across the depletion zone surrounding PCBM aggregates. Phase contrast X-ray microscopy is under rapid development, and the results presented here are promising for future studies of organic-organic blends, also under in situ conditions, e.g., for monitoring the structural stability during UV-Vis irradiation.

  9. Influence of bulk pre-straining on the size effect in nickel compression pillars

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, A.S., E-mail: Andreas.schneider@inm-gmbh.de [INM-Leibniz Institute for New Materials, Campus D2 2, 66123 Saarbruecken (Germany); Kiener, D. [University of Leoben, Department of Materials Physics, Jahnstr. 12, 8700 Leoben (Austria); Yakacki, C.M. [Department of Mechanical Engineering, University of Colorado Denver, Denver 80217 (United States); Maier, H.J. [University of Paderborn, Lehrstuhl fuer Werkstoffkunde (Materials Science), 33098 Paderborn (Germany); Gruber, P.A. [Karlsruhe Institute of Technology, Institute for Applied Materials, Kaiserstr. 12, 76131 Karlsruhe (Germany); Tamura, N.; Kunz, M. [Advanced Light Source (ALS), Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Berkeley, CA 94720 (United States); Minor, A.M. [Department of Materials Science and Engineering, University of California, Berkeley, and National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Frick, C.P. [University of Wyoming, Mechanical Engineering Department, 1000 East University Avenue, Laramie, WY 82071 (United States)

    2013-01-01

    Micro-compression tests were performed on pre-strained nickel (Ni) single crystals in order to investigate the influence of the initial dislocation arrangement on the size dependence of small-scale metal structures. A bulk Ni sample was grown using the Czochralski method and sectioned into four compression samples, which were then pre-strained to nominal strains of 5, 10, 15 and 20%. Bulk samples were then characterized using transmission electron microscopy (TEM), micro-Laue diffraction, and electron backscatter diffraction. TEM results show that a dislocation cell structure was present for all deformed samples, and Laue diffraction demonstrated that the internal strain increased with increased amount of pre-straining. Small-scale pillars with diameters from 200 nm to 5 {mu}m were focused ion beam (FIB) machined from each of the four deformed bulk samples and further compressed via a nanoindenter equipped with a flat diamond punch. Results demonstrate that bulk pre-straining inhibits the sample size effect. For heavily pre-strained bulk samples, the deformation history does not affect the stress-strain behavior, as the pillars demonstrated elevated strength and rather low strain hardening over the whole investigated size range. In situ TEM and micro-Laue diffraction measurements of pillars confirmed little change in dislocation density during pillar compression. Thus, the dislocation cell walls created by heavy bulk pre-straining become the relevant internal material structure controlling the mechanical properties, dominating the sample size effect observed in the low dislocation density regime.

  10. 29 CFR 1919.81 - Examination of bulk cargo loading or discharging spouts or suckers.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Examination of bulk cargo loading or discharging spouts or suckers. 1919.81 Section 1919.81 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) GEAR CERTIFICATION Certification of Shore-Based Material Handling Devices §...

  11. Automatic sample changer and microprocessor controlled data router for a small bulk-sample counter

    International Nuclear Information System (INIS)

    We have designed a gamma-ray counting system for small bulk-samples that incorporates an automatic sample-changer and multiple data-output device. The system includes an inexpensive microprocessor and is constructed mainly of materials and equipment commonly available at most institutions engaged in nuclear research

  12. Tailored Porous Materials

    Energy Technology Data Exchange (ETDEWEB)

    BARTON,THOMAS J.; BULL,LUCY M.; KLEMPERER,WALTER G.; LOY,DOUGLAS A.; MCENANEY,BRIAN; MISONO,MAKOTO; MONSON,PETER A.; PEZ,GUIDO; SCHERER,GEORGE W.; VARTULI,JAMES C.; YAGHI,OMAR M.

    1999-11-09

    Tailoring of porous materials involves not only chemical synthetic techniques for tailoring microscopic properties such as pore size, pore shape, pore connectivity, and pore surface reactivity, but also materials processing techniques for tailoring the meso- and the macroscopic properties of bulk materials in the form of fibers, thin films and monoliths. These issues are addressed in the context of five specific classes of porous materials: oxide molecular sieves, porous coordination solids, porous carbons, sol-gel derived oxides, and porous heteropolyanion salts. Reviews of these specific areas are preceded by a presentation of background material and review of current theoretical approaches to adsorption phenomena. A concluding section outlines current research needs and opportunities.

  13. Sub-picosecond ultraviolet laser filamentation-induced bulk modifications in fused silica

    Science.gov (United States)

    Papazoglou, D. G.; Zergioti, I.; Tzortzakis, S.; Sgouros, G.; Maravelias, G.; Christopoulos, S.; Fotakis, C.

    2005-07-01

    We present experiments with sub-picosecond ultraviolet laser pulses (248 nm, 450 fs) tightly focused in the bulk of fused-silica samples. The high laser intensities attained generate plasma through multi-photon absorption and electron avalanche processes in the bulk of the material. Depending on the initial experimental conditions three distinct types of structural changes in the material are observed, from small changes of the refractive index to birefringence, and even cracks and voids. We also observe the creation of micro-channels, up to 115 μm in length, inside the material due to self-guiding and filamentation of the laser pulses in the transparent material. The selective change of the refractive index is a promising method for the fabrication of photonic structures such as waveguides and three-dimensional integrated optical devices.

  14. Fatigue effect on polarization switching dynamics in polycrystalline bulk ferroelectrics

    Science.gov (United States)

    Zhukov, S.; Glaum, J.; Kungl, H.; Sapper, E.; Dittmer, R.; Genenko, Y. A.; von Seggern, H.

    2016-08-01

    Statistical distribution of switching times is a key information necessary to describe the dynamic response of a polycrystalline bulk ferroelectric to an applied electric field. The Inhomogeneous Field Mechanism (IFM) model offers a useful tool which allows extraction of this information from polarization switching measurements over a large time window. In this paper, the model was further developed to account for the presence of non-switchable regions in fatigued materials. Application of the IFM-analysis to bipolar electric cycling induced fatigue process of various lead-based and lead-free ferroelectric ceramics reveals different scenarios of property degradation. Insight is gained into different underlying fatigue mechanisms inherent to the investigated systems.

  15. Targets for bulk hydrogen analysis using thermal neutrons

    CERN Document Server

    Csikai, J; Buczko, C M

    2002-01-01

    The reflection property of substances can be characterized by the reflection cross-section of thermal neutrons, sigma subbeta. A combination of the targets with thin polyethylene foils allowed an estimation of the flux depression of thermal neutrons caused by a bulk sample containing highly absorbing elements or compounds. Some new and more accurate sigma subbeta values were determined by using the combined target arrangement. For the ratio, R of the reflection and the elastic scattering cross-sections of thermal neutrons, R=sigma subbeta/sigma sub E sub L a value of 0.60+-0.02 was found on the basis of the data obtained for a number of elements from H to Pb. Using this correlation factor, and the sigma sub E sub L values, the unknown sigma subbeta data can be deduced. The equivalent thicknesses, to polyethylene or hydrogen, of the different target materials were determined from the sigma subbeta values.

  16. Magnetic properties of Fe-Co-based bulk metallic glasses

    International Nuclear Information System (INIS)

    Amorphous [(Fe1-xCox)75B20Si5]93Nb4Y3(x=0, 0.2 and 0.4) have been produced by water-cooled Cu-mold injection casting technique in cylindrical shape. Amorphous ribbon having the same composition have been produced by rapid quenching technique. The presence of an amorphous structure have been checked by means of X-ray diffraction measurements and differential scanning calorimetry. Magnetic hysteresis loops have been measured by means of vibrating sample magnetometer at a maximum field of 10 kOe. In addition, to study the frequency dependence of magnetic losses, hysteresis loops have been measured by a digital wattmeter. A critical analysis of the results obtained on both ribbons and bulk cylinder will be presented. The obtained data will be compared with the ones of Fe-based materials conventionally exploited in applications.

  17. Comparison of recombination models in organic bulk heterojunction solar cells

    International Nuclear Information System (INIS)

    Recombination in bulk-heterojunction (BHJ) organic solar cells is the key loss mechanism, and it directly affects characteristic parameters such as power conversion efficiency, short-circuit current, open-circuit voltage, and fill factor. However, which recombination mechanism dominates the loss in organic materials is unclear at present. In this work, we simulate state-of-art BHJ solar cells using five recombination models, including direct recombination, Langevin recombination, charge transfer state recombination, trap-assisted recombination, and recombination via tail. All processes are strongly dependent on charge carrier mobility and exhibit a similar recombination distribution in active layer. For high mobilities, all models present a similar behavior along with the increased mobilities, whereas, there are slight differences in open-circuit voltage between trap/tail model and other ones at lower mobilities, resulting from the interaction between photo-carriers and dark-carriers

  18. Evolution of bulk damage initiation in DKDP

    Science.gov (United States)

    Carr, Christopher W.; McMillian, T. H.; Staggs, Mike C.; Radousky, Harry B.; Demos, Stavros G.

    2003-05-01

    We investigate the evolution of laser-induced damage initiated in the bulk of DKDP crystals using in-situ microscopy. Experimental results indicate that at peek fluences greater than 10 J/cm2, damage sites are formed with increasing number as a function of the laser fluence. Following plasma formation, cracks are observed which grow in size for tens of seconds after the termination of the laser pulse. Subsequent irradiation leads to modest increase in size only during the initial 2-5 pulses. Experimental results suggest that there is also relaxation of the stresses adjacent to a damage site for several hours after initial damage.

  19. Calculated Bulk Properties of the Actinide Metals

    DEFF Research Database (Denmark)

    Skriver, Hans Lomholt; Andersen, O. K.; Johansson, B.

    1978-01-01

    Self-consistent relativistic calculations of the electronic properties for seven actinides (Ac-Am) have been performed using the linear muffin-tin orbitals method within the atomic-sphere approximation. Exchange and correlation were included in the local spin-density scheme. The theory explains t...... the variation of the atomic volume and the bulk modulus through the 5f series in terms of an increasing 5f binding up to plutonium followed by a sudden localisation (through complete spin polarisation) in americium...

  20. Oscillatory Dynamical Switching System of Bulk Ferroelectrics

    Directory of Open Access Journals (Sweden)

    M. N.A. Halif

    2005-01-01

    Full Text Available This study gives a detailed account of calculation of the bulk ferroelectric (FE oscillatory dynamical system switching to first and second-order phase transition, respectively. All the formalism is delineated in the framework of Landau free-energy expansion and Landau-Khalatnikov (LK equation of motion where the effect of external energy may affray FE atoms similar to the spring damped oscillatory system. Here we scrutinized the switching properties from free-energy expansion and hysteresis loop. The polarization and current switching appropriate to the estimated complete switching time, changing of temperature, electric field and damping are scrutinized and discussed.