Energy Technology Data Exchange (ETDEWEB)

An experimental study was conducted to determine the effects of ply thickness in composite laminates on thermally induced cracking and changes in the coefficient of thermal expansion (CTE). After a few thermal cycles, laminates with thick-plies cracked, resulting in large changes in CTE. CTE`s of the thin-ply laminates were unaffected by microcracking during the first 500 thermal cycles, whereas, the CTE`s of the thick-ply laminates changed significantly. After about 1500 cycles, microdamage had also reduced the CTE of the thin-ply laminates to a value of about half of their initial value.

British Library Electronic Table of Contents (United Kingdom)

Annealing of magnetostrictive Metglas foils, subsequently incorporated into laminated Metglas/Pb(Zr, Ti)O3 magnetoelectric (ME) composites, is shown to result in improved magnetic properties, as well as ME coefficients. Annealing of the foils at 350 ?C resulted in partial crystallization, without oxidation or magnetic cluster formation that would reduce the magnetization. Laminate composites made with these annealed Metglas foils had improved ME coefficients.

Energy Technology Data Exchange (ETDEWEB)

A 1000-watt CO/sub 2/ laser has been demonstrated as a reliable production machine tool for cutting of plastics, high strength reinforced composites, and other nonmetals. More than 40 different plastics have been laser cut, and the results are tabulated. Applications for laser cutting described include fiberglass-reinforced laminates, Kevlar/epoxy composites, fiberglass-reinforced phenolics, nylon/epoxy laminates, ceramics, and disposable tooling made from acrylic.

Science.gov (United States)

A flutter-motion equation is presently derived for a 2D composite sandwich panel considering the total lateral displacement of the plate as the sum of the displacement due to bending of the plate, and that which is due to shear deformation at the core. The effects of core thickness and stacking sequence of the faces on the flutter boundary of the plate are discussed; it is shown that the sandwich panel greatly improves the flutter boundary over that of a composite laminate panel, provided it has sufficient core thickness.

Energy Technology Data Exchange (ETDEWEB)

To predict the fatigue life of fiber reinforced composites, fatigue process of CFRP laminates of [0 /90 ]{sub s} is investigated and the influence of damages occurring at fiber, matrix and fiber/matrix interface on the various critical strengths and the relationship between residual critical strength and failure are discussed. As a result, it was shown that fatigue strength (i.e. fatigue life) consisted of residual critical strength and stresses occurring at each layer (0 and 90 layers) and interlayer. Moreover, the fatigue failure occurred because the residual critical strength of each layer and interlayer decreased with dependence of their microdamage densities, so that the fatigue life can be predicted by evaluating microdamage behavior in fatigue process. (orig.) 14 refs.

International Nuclear Information System (INIS)

We solve an R -linear problem for a multiple-connected circular domain in a class of doubly periodic functions in analytic form by a method of functional equations. This problem models transport properties of two-dimensional composite materials made from a collection of disks embedded in an otherwise uniform host.

International Nuclear Information System (INIS)

A laminated material composed of glass cloth/polyimide film/epoxy resin will be used as an insulating material for superconducting coil of International Thermonuclear Experimental Reactor (ITER). In order to keep safe and stable operation of the superconducting coil system, it is indispensable to evaluate radiation resistance of the material, because the material is exposed to severe environments such as high radiation field and low temperature of 4 K. Especially, it is important to estimate the amount of gases evolved from the insulating material by irradiation, because the gases affect on the purifying system of liquid helium in the superconducting coil system. In this work, the gas evolution from the laminated material by gamma ray irradiation at liquid nitrogen temperature (77 K) was investigated, and the difference of gas evolution behavior due to difference of composition in the epoxy resin was discussed. It was found ...

Energy Technology Data Exchange (ETDEWEB)

Elastic and elasto-plastic modelling of indentation in CFRP cross-ply laminates has been performed. Detailed knowledge of the field solutions in the volume below the indentor forms the basis for the reported micromechanical interpretation of the observed damage in test specimens. The analysis shows that matrix cracks originate at sites of maximum tensile stress perpendicular to fibers. The predicted stress fields due to indentation show that stress concentrations occur in the interface between alternating plies. It is found that microcracking in this zone is a precursor to the observed failure. This analysis is supported by in-situ scanning electron microscopy during loading by a cylindrical indentor onto the laminate supported on a rigid substrate. The microscopy reveals microdamage in the region of interfacial tensile stress concentrations. The onset of indentation failure in these layered composites suggests that plastic ...

Science.gov (United States)

The results of an investigation into the behavior of adhesively bonded doubler splices of two composite material sandwich panels are presented. The splices are studied from three approaches: analytical; numerical (finite elements); and experimental. Several parameters that characterize the splice are developed to determine their influence upon joint strength. These parameters are: doubler overlap length; core stiffness; laminate bending stiffness; the size of the gap between the spliced sandwich panels; and room and elevated temperatures. Similarities and contrasts between these splices and the physically similar single and double lap joints are discussed. The results of this investigation suggest several possible approaches to improving the strength of the sandwich splices.

Science.gov (United States)

... The moisture content-dimension relationship of two laminate components, phenolic core and melamine overlay, are compared. (Author, modified). ...

British Library Electronic Table of Contents (United Kingdom)

Abstract We have experimentally and theoretically investigated the equivalent magnetic noise in a magnetoelectric Metglas/ 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 laminate sensor unit by considering the constituent noise sources of dielectric loss (NDE) and DC leakage resistance (NR). In the low frequency range (f = 1 Hz), theory predicts that NR dominates the noise charge (1.6 times larger than NDE), with a 1 Hz noise of 9.1\\;{\\rm pt}/\\sqrt {\\rm Hz}. The experimental equivalent magnetic noise was 10.8\\;{\\rm pt}/\\sqrt {\\rm Hz}. This observed value is slightly higher than the predicted one, which might be due to an oversimplification of the theoretical model in terms of electrical charge amplifier and external vibration noise sources. ( 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

International Nuclear Information System (INIS)

Comprehensive investigation has been made into the application of the polymerization hardening by radiation, particularly electron beam, to the composites of polymers and other materials. The report is divided into four parts, namely 1) characteristics and problems of the reaction of curing by radiation polymerization, 2) improvement of the bonding capability of high molecular weight materials, 3) bonding by radiation, and 4) composites made by the impregnation and polymerization hardening of monomers. The first part includes the effects of dose rate, temperature rise during the hardening, the peculiarity of electron beam irradiation at high dose rate, reaction environment and additive effects. Main conclusions are as follows: caution must be taken to the amount of residual double bonds because they affect the quality of hardened polymers; the polymerization hardening reaction at high dose rate cannot be analogized by that at low dose rate; and ...

International Nuclear Information System (INIS)

Phenolic resins have made a major breakthrough in the field of high technology in 80's. These are now active participants of "high tech' areas ranging from electronics, computers, communication, outer space, aerospace, advanced materials, bio materials and technology. A phenol - formaldehyde (1:1.5) resin having resin content of 70% synthesized in the laboratory has been applied for wood coating and reinforcing glass fiber. The weatherability and solvent resistance of these items have been studied and results discussed keeping in view the envisaged application for structural materials and chemical equipment. The toxic materials released during contact with solvents for chemical applications and during degradation general have been monitored. The results are discussed with reference to environmental pollution due to these resins and their composites under different conditions. (authors)

Energy Technology Data Exchange (ETDEWEB)

A lightweight, low permeability liner for graphite epoxy composite compressed gas storage vessels. The liner is composed of polymers that may or may not be coated with a thin layer of a low permeability material, such as silver, gold, or aluminum, deposited on a thin polymeric layer or substrate which is formed into a closed bladder using torispherical or near torispherical end caps, with or without bosses therein, about which a high strength to weight material, such as graphite epoxy composite shell, is formed to withstand the storage pressure forces. The polymeric substrate may be laminated on one or both sides with additional layers of polymeric film. The liner may be formed to a desired configuration using a dissolvable mandrel or by inflation techniques and the edges of the film seamed by heat sealing. The liner may be utilized in most any type of gas storage system, and is particularly applicable for hydrogen, gas ...

UK PubMed Central (United Kingdom)

AbstractQuantities and types of ceramides and their relationships to physical properties of the horn covering the claws of clinically normal cows and cows with subclinical laminitis were...Full Text Available

Science.gov (United States)

... Coupon 119 * 52 Probability of Survival Versus Ultimate Compressive Strength for Un-notched Laminate 1 Coupon ipn ...

International Nuclear Information System (INIS)

Information circulars are published from time to time under the symbol INFCIRC/... for the purpose of bringing matters of general interest to the attention of all Members of the Agency. The present revision contains INFCIRCs published up to mid-August 1994. A complete numerical list of information circulars is reproduced with their titles in the Annex.

Science.gov (United States)

... Title : Wear Rate and Friction Coefficient in Liquid Nitrogen and Hydrogen of Steel Sliding on Polymer Laminates (Various Fabrics and Polymers. ...

Energy Technology Data Exchange (ETDEWEB)

The nuclear lamina proteins, prelamin A, lamin B, and a 70-kD lamina-associated protein, are posttranslationally modified by a metabolite derived from mevalonate. This modification can be inhibited by treatment with (3-R,S)-3-fluoromevalonate, demonstrating that it is isoprenoid in nature. We have examined the association between isoprenoid metabolism and processing of the lamin A precursor in human and hamster cells. Inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase by mevinolin (lovastatin) specifically depletes endogenous isoprenoid pools and inhibits the conversion of prelamin A to lamin A. Prelamin A processing is also blocked by mevalonate starvation of Mev-1, a CHO cell line auxotrophic for mevalonate. Moreover, inhibition of prelamin A processing by mevinolin treatment is rapidly reversed by the addition of exogenous mevalonate. Processing of prelamin A is, therefore, dependent on isoprenoid metabolism. ...

UK PubMed Central (United Kingdom)

In several respects the dorsal thalamus of Trichosurus presents a level of organizational complexity considerably in advance of that seen in Didelphis. In particular, such features as the lamination...Full Text Available

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

To heighten durability and safety of materials/parts for undersea oil drilling, the development of ceramic base materials was made by developing function harmony type process technology which harmonizes on a high grade contrary characteristics and various functions. The paper summed up the fiscal 1997 results. In the design of system formation, computational simulation technology was developed to the composite process and the diploid system. The development of multifunction simultaneous manifestation materials was trially made by the higher nano structure process. A study was made of control of microstructures of porous materials and matrix filling by the gas phase precipitation control. Proposed were selective control of grain growth from species crystals and the columnar particle orientation laminated structure of simultaneous manifestation of strength and toughness. By composite precipitation reaction control, studied ...

Energy Technology Data Exchange (ETDEWEB)

A thesis is presented on improving the understanding of the fatigue properties of wood and fatigue failure mechanisms in the design of wind turbine blades. Three main areas were researched: the effect of R ratio on fatigue life, the effect of moisture on fatigue life and the development of cumulative damage laws. Tests were carried out on mainly four-ply laminates. Recommendations to future work are outlined. (U.K.).

Energy Technology Data Exchange (ETDEWEB)

A study was carried out to identify optimal laminate/oil combinations for low pressure oil filled and high pressure pipe-type cables, and to establish taping criteria under factory conditions. Laminates from two sources were evaluated in conjunction with Sun XX high viscosity mineral oil and Cosden 015SH polybutene oil for high pressure type cables, and Dussek TC-2288N mineral oil, Shell P2 dedecylbenzene and Chevron DF-100 alkylbenzene for low pressure oil-filled cables. Swelling tests, infrared analysis, dissipation and dielectric measurements, impulse tests and a taping trial were performed. It was found that there is no appreciable difference in performance of both laminates when tested on model cables in a variety of oils. Both types exhibited superior aging characteristics vis-a-vis cellulose paper when tested with a variety of oils and at temperatures up to 105{degree}C. For pipe type cable, high viscosity polybutene ...

Energy Technology Data Exchange (ETDEWEB)

A dielectric-wall linear accelerator is improved by a high-voltage, fast rise-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface.

Energy Technology Data Exchange (ETDEWEB)

This paper describes the development of cellulose paper/plastic film/cellulose paper laminate insulated Self-Contained 500 kV Oil-Filled (OF) Cable and its accessories. Dielectric loss of this new cable was confirmed to be about one third that of conventional kraft paper cable. Moreover, by employing the reduced insulation thickness of 25 mm rather than that of 33 mm, as is usual with conventional cables, the new cable could be made very compact, due to the high dielectric strengths of laminated paper. As a result, the shipping reel length of the new cable, which is about 10% lighter in total weight and 10% smaller in overall diameter than conventional cables, could be dramatically increased. The reliability and the stability of the new cable have been demonstrated by the successful completion of a one and a half year field test.

International Nuclear Information System (INIS)

The authors have investigated here whether tachyons can move in stable circular orbits in Kerr, Kerr-Newmann and Lewis fields owing to their dragging effect. It is found that stable circular orbits are possible only in a Lewis field. (author).

UK PubMed Central (United Kingdom)

Experimental techniques are presented that can be used to assay and correct for differential light scattering effects in circular dichroism spectra of biological macrostructures. The assay is based...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Steam generators (SG) are the weak link of nuclear power plants, their service life is shorter than the service life of other NPP components. This paper is dedicated to a statistical analysis of SG damages and failures. Heat exchanging tubes (HET) are the most damaged elements in SG, there are on average 286 plugged or repaired tubes in each operating SG. The usually mechanisms of tube failure are the following: denting, corrosion at tube outside, pitting, fretting, and circular crack propagation. Most of damages are located in the transition zone above a tube plate. This study shows that the factors that are involved in the SG HET fault probability are: - design features of SG and secondary equipment elements (high pressure feed heaters (HPFH), low pressure feed heater (LPFH)), - water chemistry at different points of condensate feed pipe, composition and density of deposits on HET surface, efficiency of mechanical and chemical washing, - the ...

UK PubMed Central (United Kingdom)

Circularly polarized X-rays produced by a diamond X-ray phase retarder of thickness 0.5 mm in the Laue transmission configuration have been used for recording X-ray magnetic circular dichroism...Full Text Available

Science.gov (United States)

The quasi-static normal indentation of sandwich panels with quasi-isotropic laminated composite skins and honeycomb or foam cores, by spherical indentors, has been investigated using experiments and finite element analysis. The experimental program emphasized the effects of indentor size on the resulting load indentation responses, failure mechanisms in the skin and the core, and the measurement of contact areas between indentor and the target. The sandwich panels were indented up to the initiation of skin fracture and the resulting contact data was used to characterize contact power laws. A non-linear finite element model was developed based on the experimental observations to systematically explore the indentation behavior of diverse sandwich configurations and to investigate the contact pressure distributions. The finite element model was used as an experimental tool in the development of a simple non-dimensional semi-empirical model that ...

Energy Technology Data Exchange (ETDEWEB)

In the present paper an attempt is made to describe transverse cracking of cross-ply ([0{sup o}{sub n}/90{sup o}{sub m}]{sub s}) laminates subjected to an external applied load and a temperature change. For this purpose a new method is suggested which was developed on the basis of the energy balance based finite fracture criterion suggested by Hashin (1996) [Hashin, Z., 1996. J. Mech. Phys. Solids 44, 1129]. In this approach the value of the specific surface energy (the critical energy release rate) is assumed to be dependent on a random microdamage distribution in the material. Hence, it is assumed to be a random function of location. A new probabilistic technique is developed to take this randomness into consideration. It is shown that only one unknown probabilistic function is required, namely the probability density function of the specific surface energy. This is determined by fitting the external stress and the corresponding crack density to experimental data ...

Science.gov (United States)

... established in allied communications publications (ACP); DISA circulars (DISAC), Joint Army-Navy-Air Force publications (JANAP), and MAJ- COM ...

Science.gov (United States)

... Calculations of asymmetric separated flow past circular ... in Missile Aerodynamics, AGARD-CP-336 ... Marconi Asymmetric separated flows about sharp ...

CERN Document Server

The production of X-ray radiation with a high degree of circular polarization constitutes an important goal at XFEL facilities. A simple scheme to obtain circular polarization control with crossed undulators has been proposed so far. In its simplest configuration the crossed undulators consist of pair of short planar undulators in crossed position separated by an electromagnetic phase shifter. An advantage of this configuration is a fast helicity switching. A drawback is that a high degree of circular polarization (over 90%) can only be achieved for lengths of the insertion devices significantly shorter than the gain length, i.e. at output power significantly lower than the saturation power level. The obvious and technically possible extension considered in this paper, is to use a setup with two or more crossed undulators separated by phase shifters. This cascade crossed undulator scheme is distinguished, in performance, by ...

Science.gov (United States)

Several central results of the method of structural formulae for some classes of analytic functions, which were known before for a disc and an annulus, are generalized to analytic functions in a finitely connected circular domain.

UK PubMed Central (United Kingdom)

Hepatitis delta virus (HDV) contains a viroid-like circular RNA that replicates via a double rolling circle replication mechanism. It is generally assumed that HDV RNA is synthesized and remains exclusively...Full Text Available

CERN Document Server

In light beams with circular or elliptic polarization, the transverse energy flow consists of the "spin" and "orbital" parts. Both of them can induce the orbital motion of microparticles suspended within the field of a light beam, and this should be taken into account in experiments on the spin-to-orbital angular momentum conversion. The character of the spin, orbital and total transverse energy flows in circular Laguerre-Gaussian beams is studied analytically; graphical representations of the flows in the beam cross section (flow maps) are calculated and analyzed. The spin circulatory flow can be directed oppositely to the orbital one and/or to the polarization handedness. As a result, the total transverse energy circulation of a beam with homogeneous circular polarization can be of different handedness in different regions of the beam cross section, which are separated by the contours of zero transverse energy flow. ...

Science.gov (United States)

An exact solution method for the free vibration problem of thin circular cylindrical shells is presented. The differential equations of motion are solved directly with the use of simple Fourier series as the modal displacement functions. Stokes' transformation is exploited to obtain correct series expressions for the derivatives of the Fourier series. From this method an explicit expression of the exact frequency equation can be obtained for any kind of boundary conditions. The accuracy of the present method is checked against available data. The proposed method is then used to find the modal characteristics of the thermal liner of the Fast Test Reactor (FTR). The numerical results obtained are compared with finite element method solutions. (auth)

International Nuclear Information System (INIS)

The mass distribution of the Sombrero Galaxy, NGC 4594, is calculated in order to investigate the suspicion that the rotational velocity of the galactic gas does not measure the circular velocity in the galaxy. It is shown that the H II rotation velocities are much less than circular in the central 35 arcsec of the galaxy, and that the suspicion is correct. Thus, the H II rotation velocities cannot be used to measure the mass distribution. The absorption-line rotation curve is used to derive the mass distribution, and it is found that the M/L ratio is nearly constant. It is concluded that the visible matter is self-gravitating at least in the central 180 arcsec. 44 references.

Science.gov (United States)

Constant property, laminar flow heat transfer in a semicircular tube with uniform wall temperature has been analyzed to define the lower bound of heat transfer augmentation in circular tubes with twisted-tape inserts. Two thermal boundary conditions, which correspond to the two extremes of the fin effect of twisted tapes encountered in practical applications, are considered. Numerical solutions, employing finite-difference formulations for the governing momentum and energy equations were carried out for the thermal entrance region and for fully developed flow.

Energy Technology Data Exchange (ETDEWEB)

The objective of the present study is to reveal thermal characteristic of microcapsulated lauric acid slurry in circular pipe. Test were performed with microcapsulated lauric acid slurry in a heating test section with a constant heat flux boundary condition. Local Nusselt number and the effective thermal capacity were measured. As the size of microcapsulated lauric acid were increased, local Nusselt number of microcapsulated lauric acid slurry were increased. The effective thermal capacity of microcapsulated lauric acid slurry was 0.5 times than it of water.

International Nuclear Information System (INIS)

... radiation effects RADIATIONS. WOOD-PLASTIC COMPOSITES.

International Science & Technology Center (ISTC)

New Composite Multifunctional Coatings Produced Using SHS-Electrodes

International Science & Technology Center (ISTC)

Development of Ceramic Composite Materials and Structural Elements for High-Temperature Nuclear Reactors

Energy Technology Data Exchange (ETDEWEB)

Flame lengths inside circular tubes, using an (in-shot) atmospheric burner design commonly found in gas-fired residential furnaces were visually observed for natural gas and air under various operating conditions. The flame length data were reduced into dimensionless flame lengths, which were shown to be linearly proportional to the Peclet number of the fuel and air mixture. The dimensionless flame length dependence reported does not scale according to the classical flame models: pre-mixed (laminar) flame or diffusion flame. Instead, the flame length dependence was found to scale with the fuel burn speed, gas/mixture properties (evaluated at the adiabatic flame temperature), and flow parameters. Currently, this is the only flame length study available for the standard atmospheric burner designs commonly used in residential heating products. The results and data reduction provide an easy method to compute flame length penetrations inside ...

Energy Technology Data Exchange (ETDEWEB)

The heat transfer a characteristics and friction factor in the horizontal double pipes of flat tubes with full length helical screw element of different twist ratio and helical screw inserts with different spacer length are investigated. Cold and hot water are used as working fluid in tube side and shell side respectively. The experiments covered a range of Reynolds numbers 5.7 x 10{sup 2} {<=} Re {<=} 1.31 x 10{sup 3}. The effect of spacer length on the heat transfer augmentation and friction factor and the effect of twist ratio on heat transfer augmentation and friction factor have been presented separately. The study shows that, the Nusslet number (Nu) and friction factor (f) decrease with the increase of S or Y for flat tube. The comparison between the data of present plain circular with that of previous plain circular tube showed a good agreement between them but the data of present plain flat tube showed a higher in heat ...

Science.gov (United States)

Light Weight Composite Mirrors for Science Instruments. Composite Optics, Inc. San Diego, CA. INNOVATION. Light weight, large aperture reflectors of graphite ...

Science.gov (United States)

The present study numerically investigates the enhancement of forced convective heat transfer from a single circular cylinder embedded in a packed bed of spherical particles confined by two impermeable parallel plates. The heat transfer results from the heated cylinder, with and without the presence of a porous medium, are compared. The results show that the presence of the porous particles enhances the heat transfer from the cylinder; however, the significant heat transfer augmentation is produced at high Re due to the effect of thermal dispersion. In addition, the effect of Re on Nut is much greater than that of kr and Bi in the porous channel. It is also found that the %?p is much higher than %HTE producing from packing the empty channel.

Science.gov (United States)

Linearly polarized laser radiation accelerates electrons to very high velocities and these electron form a sheath layer on the rear side of thin targets where preferentially protons are accelerated. When mass-limited targets are used, the lateral transport of the absorbed laser energy is reduced and the accelerating field is enhanced. For targets consisting of two ion species, heavier ions facilitate formation of quasi-monoenergetic bunch of lighter ions. For circularly polarized light, fast electron production is suppressed by the absence of the oscillatory component of the ponderomotive force. Ions are accelerated on the front side by the separation field and very thin foil can be accelerated as one massive quasi-neutral block. As all ion species acquire the same velocity, this acceleration mechanism is preferred for heavier ions.

British Library Electronic Table of Contents (United Kingdom)

A nonlinear free boundary-value problem of supercavitating flow past n + 1 hydrofoils is analyzed. To describe the cavities' closure mechanism, the Tulin-Terentev single-spiral-vortex model is employed. The flow domain is considered as the image of an (n + 1)-connected circular domain. The conformal map is constructed in terms of the solutions to two Riemann-Hilbert problems of the theory of symmetric automorphic functions. One of the problems is homogeneous and its coefficients are continuous functions while the second problem is inhomogeneous and has discontinuous coefficients. The exact solutions to the problems are found by using quasiautomorphic and quasimultiplicative analogs of the Cauchy kernel. The case of a single plate is considered in detail and the numerical results are report...

Energy Technology Data Exchange (ETDEWEB)

Three-dimensional seismic wavefields may be extrapolated in depth, one frequency at a time, by two-dimensional convolution with a circularly symmetric, frequency- and velocity-dependent filter. This depth extrapolation, performed for each frequency independently, lies at the heart of 3-D finite-difference depth migration. The computational efficiency of 3-D depth migration depends directly on the efficiency of this depth extrapolation. McClellan transformations provide an efficient method for both designing and implementing two-dimensional digital filters that have a particular form of symmetry, such as the circularly symmetric depth extrapolation filters used in 3-D depth migration. Given the coefficients of one-dimensional, frequency- and velocity-dependent filters used to accomplish 2-D depth migration, McClellan transformations lead to a simple and efficient algorithm for 3-D depth migration. 21 refs., 12 figs.

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Norwegian Open Research Archives (NORA)

Full Text Available

Science.gov (United States)

Not Available

International Nuclear Information System (INIS)

The influence of electron-beam irradiation on mechanical properties of commercial multilayer flexible packaging materials based on coextruded and laminated polypropylene (PP), low-density polyethylene (LDPE), ethylene vinyl alcohol copolymer (EVOH) and poly(ethylene terephthalate) (PET), irradiated with doses up to 120 kGy, was studied. The tensile strength and elongation at break of the irradiated PET/PP film increase, while the penetration and sealing resistance decreased. In addition, the irradiated PET/LDPE/EVOH/LDPE film presented increase in the tensile strength on some radiation doses and decrease of the penetration and sealing resistance, except for sealing resistance at radiation dose of 15 kGy that resulted in a slight increase of ca 4%.

International Science & Technology Center (ISTC)

Thermodynamic Stable Metal Compositions for Improvement of an Operational Safety of Constructional Materials under Conditions of Multifactor Loadings of an Aggressive Environment

Science.gov (United States)

... Accession Number : ADD345858. Title : Nondestructive Testing of Polymeric Composite Sandwich Panels Via the Thermographic Halo,. ...

Energy Technology Data Exchange (ETDEWEB)

A fuel composition comprising a liquid hydrocarbon fuel and a detergent amount of the product of reaction between a polyamine and a stearic acid is described.

Science.gov (United States)

the progressive simplification of composite sandwich panels. The equations ... The thermal and structural behavior of composite sandwich panels with a ...

Science.gov (United States)

... polypropylene, polylactic acid and polyvinyl chloride to form wood plastic composites (WPC). WPCs have seen a large growth in ... ...

Energy Technology Data Exchange (ETDEWEB)

Methods of designing ultrasonic piezoelectric transducers in accord with a specified directivity pattern are analyzed and general formulas are presented for the design problem. As an example, the pressure distribution on the working surface of a circular piezoelectric transducer is determined that is capable of forming a narrow weakly divergent beam. Experimental results are presented with respected to ultrasonic fields that support the theoretical conclusions.

UK PubMed Central (United Kingdom)

The Bacillus anthracis Sterne plasmid pXO1 was sequenced by random, “shotgun” cloning. A circular sequence of 181,654 bp was generated. One hundred forty-three open...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Effective barrier pillar design is essential for safe and productive underground coal mining. This U.S. Bureau of Mines report presents an overview of available barrier pillar design methodologies that incorporate sound engineering principles while remaining practical for everyday usage. Nomographs and examples are presented to assist in the determination of proper barrier pillar sizing. Additionally, performance evaluation techniques and criteria are included to assist in determining the effectiveness of selected barrier pillar configurations.

Energy Technology Data Exchange (ETDEWEB)

A complete theory for waveguide laser modes for oversized metallic and dielectric waveguides with circular cross section has been developed for the submillimeter wavelength region. The experimental investigations have been done by a submillimeter heterodyne technique for the first stage using a Schottky barrier diode in an open structure mixer.

UK PubMed Central (United Kingdom)

Amplification of oncogenes has been found to be an important prognostic factor in behavior of patients' malignancies. In this study we have used new gel electrophoresis techniques to follow the location...Full Text Available

International Nuclear Information System (INIS)

Critical power characteristics of tight lattice rod assembly was investigated using a simple-shaped experimental apparatus. An electrically heated rod with four spacers was placed in a circular tube, and boiling transition condition for a rod in an annular geometry was clarified varing annulus clearance. It was found that critical heat flux depends strongly on the clearance accoding as the gap becomes smaller. This results was compared with KfK correlation and the trends were well correlated. (author).

International Nuclear Information System (INIS)

This book contains nine selections. Some of the titles are: High Heat-Flux, Forced-Convection Heat Transfer for Tubes with Twisted-Tape Inserts; Heat Transfer Augmentation by Interrupted Surfaces - Experimental Consideration; Turbulent Flow Heat Transfer from Externally Roughened Tubes in Axial Flow in Concentric Pipe Heat Exchangers; and Heat Transfer Enhancement of Turbulent Flow in Pipes with an Internal Circular Rib.

British Library Electronic Table of Contents (United Kingdom)

In this research, hybrid composite materials were prepared from combination of oil palm Empty fruit bunches (EFB) fibre and jute fibre as reinforcement, epoxy as polymer matrix. This study intended to investigate the effect of jute fiber hybridization and different layering pattern on the physical properties of oil palm EFB-Epoxy composites. Water absorption and thickness swelling test reveal that hybrid composite shows a moderate water absorption which is 11.20% for hybrid EFB/Jute/EFB composite and 6.08% for hybrid Jute/EFB/Jute composite. The thickness swelling and water absorption of the hybrid composites slightly increased as the layering pattern of hybrid composites changed. Hybrid composites are more water resistance and dimensional stable compare to the pure EFB composites. This is...

Energy Technology Data Exchange (ETDEWEB)

Approximately 700m of deep water clastic deposits of Mt. Messenger Formation are superbly exposed along the Taranaki coast of North Island, New Zealand. Biostratigraphy indicates the interval was deposited during the time span 10.5-9.2m.y. in water depths grading upward from lower bathyal to middle-upper bathyal. This interval is considered part of a 3rd order depositional sequence deposited under conditions of fluctuating relative sea-level, concomitant with high sedimentation rates. Several 4th order depositional sequences, reflecting successive sea-level falls, are recognized within the interval. Sequence boundaries display a range of erosive morphologies from metre-wide canyons to scours several hundred metres across. All components of a generic lowstand systems tract--basin floor fan, channel-levee complex and progading complex--are present in logical and temporal order. They are repetitive through the interval, with the relatively shallower-water components becoming more ...

British Library Electronic Table of Contents (United Kingdom)

A tobermorite/hydroxyapatite composite was prepared by hydrothermal treatment using diatomaceous earth, ?-tricalcium phosphate and slaked lime starting materials. The XRD patterns of the composite confirmed that tobermorite and hydroxyapatite were formed after the hydrothermal process. The bending strength of the composite reached a level higher than 9?MPa after the hydrothermal process. The development of the bending strength was due to the formation of tobermorite and hydroxyapatite during the hydrothermal process. The composite had a high specific surface area due to these newly formed crystals.

Science.gov (United States)

A process is provided for conducting organic compound conversion over a catalyst composition comprising a supported crystalline zeolite having a high initial silica-to-alumina mole ratio, said supported zeolite being prepared by compositing said crystalline zeolite with alumina, reacting the composite with a particular hydrogen fluoride solution in a specified way, drying the hydrogen fluoride reacted composite, treating the dried composite by hydrolysis, ammonolysis and/or by contact with an ammonium salt solution, and calcining the resulting material.

International Nuclear Information System (INIS)

Effect of nitrogen-containing additives in the study of wood plastic composites of MMA with simul and mango wood of Bangladesh has been investigated. Nine different additives were used and the additives containing carboamide group induce the highest tensile strength to the composite. (author).

Energy Technology Data Exchange (ETDEWEB)

A composite is any combination of two or more resources held together by some type of mastic or matrix. This report will describe several different types of composites with regard to thermoplasticization, improved mechanical properties, and stiffness.

UK PubMed Central (United Kingdom)

Dimethacrylate polymers and composites are seeing increased usage in orthopedics. As these applications require the material to integrate with the surrounding tissues, direct contact cytotoxicity...Full Text Available

International Nuclear Information System (INIS)

A new model for short-range isoscalar current in the deuteron and NN system is developed and tested on a variety of isoscalar magnetic observables such as the deuteron magnetic moment, magnetic form factor, and the circular polarization of photons at n"#->#p radiative capture at thermal neutron energies. The model for electromagnetic two-nucleon current proposed in the paper is based on generation of an intermediate dibaryon in the short-range NN interaction. This intermediate dibaryon, in turn, is treated within the new model for intermediate and short-range NN interaction recently proposed by the present authors. The transition current model developed here satisfies the current conservation relation by the construction. Our calculations have demonstrated that the new current model, using only one parameter (with a clear physical meaning), is able to describe, in very good agreement with the experimental data, three basic deuteron observables of magnetic type, ...

Energy Technology Data Exchange (ETDEWEB)

Magnetic imaging in the transmission electron microscope (TEM) has been used to examine submicron elements with the aim of discovering down to what element size complex domain patterns can form. The elements were squares, circles, triangles, and pentagons in the size range 100{endash}500 nm and were made from 36 nm Co films or 8 nm Ni{sub 80}Fe{sub 20} (NiFe) with in-plane magnetization. The magnetic domain structures in these elements were imaged at high resolution using the differential phase contrast imaging mode in a TEM. Nonuniform magnetization structures were seen in the images. Vortices were present at remanence in all shapes of 36-nm-thick Co elements down to 100 nm size and in circular NiFe elements down to 116 nm diameter. Triangular NiFe elements did not have a vortex state at remanence, instead the magnetization curved round within the element but did not achieve complete flux closure. In simulations of square and circular NiFe ...

International Nuclear Information System (INIS)

In the utilization of the thermal energy by ocean temperature difference and factory waste heat, the high performance heating surfaces in pipes from which scale can be removed are required. As the method of removing scale, the method using sponge balls seems most suitable, but for applying this method, as the form of the protrusions attached to the inner surfaces of pipes, smooth circular are form is desirable. The promotion of heat transfer with the rows of circular arc protrusions like this is strongly related to the mode of flow and such structure as separation, recirculation flow, readhesion and turbulent energy generation. In this study, as the basic research to optimize the heating surface with the rows of smooth protrusions, the flow characteristics and the heat transfer characteristics including the turbulent structure of the wake of protrusions were experimentally determined, and the essence of the heat transfer characteristics was to ...

Science.gov (United States)

We present an x-ray magnetic circular dichroism (XMCD) study performed on both Ho{sub 6}Fe{sub 23} and Y{sub 6}Fe{sub 23} compounds as a function of the temperature. The combined analysis of both Fe K-edge and Ho L{sub 2,3}-edge XMCD spectra recorded through the magnetic compensation transition allows us to disentangle the thermal dependence of both Fe and Ho magnetic moments in Ho{sub 6}Fe{sub 23}. In addition, contributions from Ho ions to the Fe K-edge XMCD signals and, conversely, from Fe ions to the Ho L{sub 2,3}-edge XMCD spectra have been clearly identified. These extra contributions, arising from the strong Fe(3d)-Ho(5d) hybridization, have been isolated from the spectra and correlated with the magnetic state of both Ho and Fe ions surrounding the absorbing site. The influence of these contributions to the values of the orbital and spin moments derived by using sum rule analysis is also shown.

Energy Technology Data Exchange (ETDEWEB)

A study on development of magnetic drive packless valves for commercial purpose showed the results as follows; 1. Study on the radial rays effecting to the permanent magnets -Measurement of the strength of Nd-magnets according to irradiation of radial rays. 2. Effects of temperature on the magnetic driving device -Temperature dependency of the Nd-casting magnets. -Effects of temperature on the heat releasing fins of high-temperature valve. 3. Optimization of torque -Arranging method of permanent magnets -Measuring method and results of torque. 4. Design, manufacture and test for the pressure-resisting structure of magnetic power transmitting device -Calculation and design for the flat circular plates under pressure of the magnetic power transmitting device -Design, manufacture and test for the pressure-resisting structure of magnetic power transmitting device -Comparison of the characteristics between magnetic drive valve and general/bellows-sealed valves. 5. ...

Energy Technology Data Exchange (ETDEWEB)

This paper deals with the buffeting of a slender, circular, flexible beam-rod in an axial turbulent flow. The principal excitation mechanisms are the turbulent wall pressure fluctuations and the motion-dependent (self-excited) aerodynamic force caused by the beam motion. On the assumption that the turbulent wall pressure fluctuations are independent of the beam motion, a linear forced-vibration model is used to determine the buffeting response of the beam and to investigate the length scale effects of turbulences on the beam buffeting. Transverse buffeting of the beam in an axial turbulent flow depends largely on the ratio of the longitudinal scale of the turbulences to the bending wavelength of the beam and on the ratio of the circumferential scale of the turbulences to the radius of the beam. The spectra and the mean square values of the buffeting displacement of the beam become vanishingly small, both when either of these ratios is very small (<10/sup -2/) ...

UK PubMed Central (United Kingdom)

The relative role of the maternal source and the filial sink in controlling the composition of maize (Zea mays L.) kernels is unclear and may be influenced by the genotype and the N...Full Text Available

Science.gov (United States)

Composite Sandwich Panels under Different Thermal Environments, Composite Structures, Vol. 25,. July 1993, pp. 227239. 11. Ko, William L., Mechanical and ...

Energy Technology Data Exchange (ETDEWEB)

As a new composition of matter, alkali metal or ammonium or tetraalkylammonium diazidoperfluorophthalocyanatoferrate. Other embodiments of the invention comprise compositions wherein the metal of the coordination complex is cobalt, manganese and chromium.

Science.gov (United States)

... Accession Number : ADD442819. Title : Instrumeted Impact Testing of Composite Sandwich Panels,. Corporate Author : AUBURN UNIV AL. ...

Science.gov (United States)

hlgh fiber content composites met the minlmum requirements. (1400 O F ) , the hlgher fiber content as-fabricated composites have impact strengths distinctly ...

CERN Document Server

Composition of the Scientific Policy Committee Appointment of Two New Members by the Chairman of the Committee (J. Specht, A. Wroblewski)

Science.gov (United States)

A Composite Architecture for Network Security at JPL. Robert B. Mead, Tom G. Dearmond, and Joseph S. Sherif. JPL, California Institute of Technology ...

Energy Technology Data Exchange (ETDEWEB)

The present investigation represents the initial phase of a comprehensive experimental program designed to study the potential for increasing the heat transfer per unit pressure drop in a ribbed duct by positioning vortex generators at key locations in the flow. In particular, the present investigation consists of a rib positioned at the inlet to a rectangular test section with uniform heating at its bottom wall. Local and average Nusselt number results are obtained for a circular rod positioned either immediately above or just downstream of the rib.

CERN Document Server

Charged particle beams in circular accelerators couple with their surroundings through induced electromagnetic fields. This interaction can be described by so-called coupling impedances. In the frequency domain the impedance in connection with the bunch spectrum allows for stability analysis and estimates. However, for simulation codes one usually needs the wakefunction, the equivalent of the impedance in time domain. Recently the transverse impedance of a cylindrical pipe with arbitrary surface impedance was given by L. Vos. An expression for the wakefunction of this transverse resistive wall impedance with inductive bypass is derived here.

International Nuclear Information System (INIS)

In this work, the effects of the focus ion beam (FIB) milling process on the optical properties of semiconductor nanostructures were investigated. With this aim, a sensitive materials system based on InGaAs/GaAs quantum dots with well known and excellent optical properties was selected for the FIB treatment. The FIB technique was used to locally remove a metallic mask deposited on top of the quantum dot sample. The photoluminescence (PL) signal, collected from the circular openings, was used to infer the possible damage effects of the ion beam on the properties of the dots.

Energy Technology Data Exchange (ETDEWEB)

The invention concerns a solar power station with a hollow solar heater, which has reflected radiation coming in, focussed by a mirror through the inlet opening. To match the differing solar radiation during the day, the inlet opening can be adjusted by changing its cross-section. This is done by at least two thick flat circular parts which can move relative to each other which are preferably movable relative to each other in pairs on a common rail and which are cooled by a coolant which is the working medium for absorbing solar energy.

Energy Technology Data Exchange (ETDEWEB)

We present a study of the interaction between Josephson junctions in circular superconducting rings and non-classical microwaves, treating both quantum mechanically. A Hamiltonian that describes both inductive and capacitive coupling between the two systems is derived within the external field approximation. Other Hamiltonians which go beyond the external field approximation, and describe explicitly the interaction of the quantum circuit that produces the non-classical microwaves with the Josephson junction circuit, are also presented. A comparison between current experiments which use classical electromagnetic fields and the proposed experiments that use non-classical microwaves, is made. (orig.) With 6 figs., 32 refs.

Science.gov (United States)

The method of reactivity determination using noise analysis correlation measurements with /sup 252/Cf was used to determine the reactivity for subcritical 17.77-cm-dia uranium (93.2 wt percent /sup 235/U) metal cylinders with reactivities as low as 25 dollars. Far subcritical tests were performed with right circular cylinders of uranium metal for which the subcritical reactivity was known from other inverse kinetics and prompt neutron decay constant measurements.

International Nuclear Information System (INIS)

Several recent experiments on micro- (or nano-) structured samples of ferromagnetic materials are introduced. Magnetization reversal phenomena are investigated on submicron wire samples of trilayer structure using the giant magnetoresistance effect. Domain wall movements are sensitively monitored by resistivity measurements and the velocity of propagation is determined. The contribution of domain wall to the resistivity is argued from the results on artificially designed samples of a spring-magnet system. In circular dots of permalloy, the existence of vortex magnetization is confirmed and the reversal of the vortex core magnetization is studied from magnetic force microscopy measurements. (author)

DEFF Research Database (Denmark)

Axially symmetric waveguides, resonators, and scatterers of arbitrary cross section and anisotropy in the cross section can be modeled rigorously with use of 2-D Cartesian-grid based codes by means of mere redefinition of material permittivity and permeability profiles. The method is illustrated by the frequencydomain simulations of resonant modes in a circular-cylinder cavity with perfectly conducting walls, a shielded uniaxial anisotropic dielectric cylinder, and an open dielectric sphere for which, after proper implementation of the perfectly matched layer boundary conditions, the radiation quality factor is also determined.

International Nuclear Information System (INIS)

The geodesic equation for space-like objects moving along a circular trajectory in the expanding universe is considered. Our analysis leads to the conclusion that ancient cosmological tachyons may exist in the present-day world and may play an important role in (i) the internal structure of hadrons conceived as nonlocal objects called strings, (ii) the T-symmetry violation observed in the weak K-decays, (iii) the multidimensional unified field theories of Kaluza-Klein type, and in (iv) the classical models of charged particles which combine ordinary electromagnetism with a self-interacting version of Newtonian gravity. 18 refs.

International Nuclear Information System (INIS)

The rapid circularization and synchronization of the stellar components in an eccentric binary system at the onset of Roche lobe overflow is a fundamental assumption common to all binary stellar evolution and population synthesis codes, even though the validity of this assumption is questionable both theoretically and observationally. Here we calculate the evolution of the orbital elements of an eccentric binary through the direct three-body integration of a massive particle ejected through the inner Lagrangian point of the donor star at periastron. The trajectory of this particle leads to three possible outcomes: direct accretion onto the companion star within a single orbit, self-accretion back onto the donor star within a single orbit, or a quasi-periodic orbit around the companion star, possibly leading to the formation of a disk. We calculate the secular evolution of the binary orbit in the first two cases and conclude that direct impact accretion can increase ...

Energy Technology Data Exchange (ETDEWEB)

The durability of ball bearings, 32-mm- and 45-mm-bore, with a retainer or glass cloth-polytetrafluoroethylene (PTFE) laminate was tested under a high radial load at a speed of 20,000 rpm in LOX or LN2. The retainers were characterized as good self-lubricators because the abrasive glass-cloth fiber tips exposed on the retainer were chemicaly etched away with hydrofluoric acid (HF). During testing, the bearing-cartridge-acceleration was monitored to detect bearing damage. Testing in LOX for about 2.2 hr showed that excellent lubricating conditions were obtained for all bearings. Testing in LN2 for about 5.1 hr detected that the fatigue life of the bearing was about the same as the calculated B10 fatigue life. The HF chemical treatment resulted in a reacted fluoride-oxide material which remained in the etched part of the glass fiber. Several chemical products, particularly MgO, CaO, and CaCO3, enhanced adhesion of PTFE transfer film to the counterface, resulting in ...

Energy Technology Data Exchange (ETDEWEB)

Kevlar 49/epoxy laminates often exhibit substantial material nonlinearity when subjected to bending. This is a consequence of the yeild-like behavior of a Kevlar 49/epoxy lamina in fiber-directed compression. In this paper, analyses that utilize a simple idealization of compressive yielding are described and calculated results for Kevlar 49 reinforced beams and rings are compared with available data. First, results of a finite element analysis of a thin, unidirectionally reinforced ring subjected to diametral compression are presented. This analysis uses beam elements that incorporate linear tensile and elastic-perfectly plastic compressive behavior. Then a method used to analyze quasi-isotropic beams tested in four-point bending is discussed. This finite element analysis uses a layered shell element with a lamina constitutive model that permits elastic-perfectly plastic response to fiber-directed compression, but otherwise assumes linear elastic behavior. ...

Energy Technology Data Exchange (ETDEWEB)

The effect of atmospheric pressure on tracking resistance of organic insulating materials were investigated in the range of 500 to 1007 hPa. The tracking resistance for Polycarbonate (PC), Modified Polyphenylene Oxide (M-PPO) and Paper Base Phenolic Resin Laminate (PL) increase with the decrease in atmospheric pressure. The scintillating discharges on these samples surface lead to the ignition. The tracking failure on these results from the ignition on the surface. For Polybutylene Terephthalate (PBT) and Polyethylene Terephthalate (PET), the tracking resistance decrease with the decrease in atmospheric pressure. The discharges observed on the these surface are the glow-like. The discharge area spreads on the surface between the electrodes at the lower pressure. The failure on this group results from the carbonization by the discharges on the surface. However, the tracking resistance for Unsaturated Polyester Resins (UP) has no significant dependence on lower ...

Energy Technology Data Exchange (ETDEWEB)

A multi-stage, multi-disk type seismic source was developed as a downhole seismic source. The seismic source is an improved version of the downhole seismic source of a system in which an elastic wave is generated by a weight accelerated by restitutive force of a spring striking the upper part of a laminated structure consisted of metal disks and elastic bodies installed in water in a well. Enhancing the vibration exciting efficiency requires impedance radiated from the disks to be increased. The multi-disk structure was adopted because of restrictions on the disk area under the limiting condition of being inside the well. Further limitation has still existed, which led to finally structuring the multi-disk type to a multi-stage construction to increase the radiated impedance. In order to increase average velocity on the radiation surface, mass relationship between the hammer and the anvil was sought so that the maximum velocity is achieved at the process of ...

Science.gov (United States)

... and testing of unidirectional composites, there are serious doubts about the possibility of obtaining a true ultimate compressive strength for this kind ...

Science.gov (United States)

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KoreaScience (Korea)

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KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

The method of production of xAl{sub 2}O{sub 3}-yTiO{sub 2} compositions provides for the depth distribution of coating components and specifies its mechanical properties. In case of the composition obtained by cladding, titanium is mainly concentrated at the substrate. In case of mechanical mixture or composition obtained by sintering the oxides, the depth distribution of coating components is random.

KoreaScience (Korea)

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Science.gov (United States)

... slenderness ratio. Equations which determine the ultimate compressive strength of a composite were established. Several ...

KoreaScience (Korea)

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KoreaScience (Korea)

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KoreaScience (Korea)

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KoreaScience (Korea)

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KoreaScience (Korea)

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KoreaScience (Korea)

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Science.gov (United States)

... Descriptors : *PROPELLING CHARGES, *NITROCELLULOSE, *COMBUSTIBLE CARTRIDGE CASES, DENSITY, FIBERS, MANUFACTURING ...

KoreaScience (Korea)

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KoreaScience (Korea)

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Science.gov (United States)

... Descriptors : *POLYMERS, *BINDERS, *HOWITZERS, *COMBUSTIBLE CARTRIDGE CASES, CHEMICAL COMPOSITION, PROPELLING ...

International Nuclear Information System (INIS)

Wood plastic composites are prepared under radiation of "6"0Co gamma source with simul, a low grade wood of Bangladesh using a water soluble monomer acrylamide (AM) mixed with a swelling solvent methanol, water or methanol/water (1:1) at different compositions in the presence of a number of additives and co-additives such as NVP (N-vinylpyrrolidone), TPGDA (tripropylene glycol diacrylate), TMPTA (trimethylol propane triacrylate), sulfuric acid, urea and copper sulfate. Polymer loading (PL) and tensile strength (TS) of the composites are measured. The role of these additives on the composites is also discussed. It is observed that nitrogen-atom containing-materials like urea, NVP and AM produce composites with the highest mechanical strength, and incorporation of copper into this system provides additional property of protection and preservation of the composites ...

International Nuclear Information System (INIS)

Polymerizing effects of high energy radiation has been found suitable for preparation of wood-polymer composites. In the present work after evaluating polymer products that have been obtained by irradiation method, wood-polymer composites have been prepared by in situ polymerization of vinyl acetate, acrylic acid and acrylic acid/styrene mixture using two samples of Iranian hardwoods, Beech and Hornbeam. These woods and their composites have been tested for their physical and mechanical properties. The results have shown that chemical bonding between polymer and the cell wall component lead to better strength properties in the composites. (author).

International Nuclear Information System (INIS)

There is growing interest in the use of natural fibres as the reinforcements for polymer composites in the automotive industry and as matrix for composites in building products application to replace synthetic fibres. In this respect the aim of this study is to develop an environmental friendly composites for furniture industry based on EFB fibres and sago starch. In this preliminary study, a basic composition and processing of EFB fibres-sago starch composites were established and the properties of the composites were determined. EFB fibre content was varied between 50-80% by weight. The amount of sago starch in liquid form was also varied and final weight percentage of sago starch added into the EFB fibres was adjusted accordingly. The mixtures of EFB fibres and sago starch were blended using Haake Rheomixer. The preliminary results indicate that the impact ...

Energy Technology Data Exchange (ETDEWEB)

To study the effect of CuO on the electrochemical properties of MgNi alloy, the MgNi-xCuO (x = 3, 5 and 10 wt%) composites were prepared by ball-milling method. The X-ray diffraction (XRD) analysis showed that the structures of the composites were amorphous. The cycle stability of the composites was improved compared to pure MgNi alloy due to the enhancement of the anti-corrosion property in the alkaline electrolyte, and the composite with 5 wt% CuO ball-milled for 15 h exhibited the best performance. Electrochemical impedance spectroscopy (EIS) and potential-step measurements indicated that the electrochemical kinetics of the composites was improved.

Energy Technology Data Exchange (ETDEWEB)

A measurement of the magnetic form factor of a ferromagnetic actinide compound of UTe with circularly polarized X-rays is reported. The present geometrical configuration of the measurement gives a form factor of L(k)+0.3S(k), where L(k) and S(k) are the form factors of the orbital and the spin magnetic moment, respectively. We have combined the X-ray magnetic form factor with the neutron one which gives L(k)+2S(k) (G. Busch et al.: J. Phys. C 12 (1979) 1391), and have deduced L(k) and S(k) separately. The obtained profiles of L(k) and S(k) show that the orbital and the spin magnetic moments are spatially spread out more than those calculated for a free uranium ion. (author).

CERN Document Server

A new class of (not necessarily bounded) operators related to (mainly infinite) directed trees is introduced and investigated. Operators in question are to be considered as a generalization of classical weighted shifts, on the one hand, and of weighted adjacency operators, on the other; they are called weighted shifts on directed trees. The basic properties of such operators, including closedness, adjoints, polar decomposition and moduli are studied. Circularity and the Fredholmness of weighted shifts on directed trees are discussed. The relationships between domains of a weighted shift on a directed tree and its adjoint are described. Hyponormality, cohyponormality, subnormality and complete hyperexpansivity of such operators are entirely characterized in terms of their weights. Related questions that arose during the study of the topic are solved as well. Particular trees with one branching vertex are intensively studied mostly in the context of subnormality and ...

CERN Document Server

We formulate a complete theory of Edge Radiation based on a novel method relying on Fourier Optics techniques. Similar types of radiation like Transition Undulator Radiation are addressed in the framework of the same formalism. Special attention is payed in discussing the validity of approximations upon which the theory is built. Our study makes consistent use of both similarity techniques and comparisons with numerical results from simulation. We discuss both near and far zone. Physical understanding of many asymptotes is discussed. Based on the solution of the field equation with a tensor Green's function technique, we also discuss an analytical model to describe the presence of a vacuum chamber. In particular, explicit calculations for a circular vacuum chamber are reported. Finally, we consider the use of Edge Radiation as a tool for electron beam diagnostics. We discuss Coherent Edge Radiation, Extraction of Edge Radiation by a mirror, and other issues ...

CERN Document Server

We present mid-infrared spectro-imagery and high-resolution spectroscopy ofthe Orion bar and of a region in the Orion nebula. These observations have beenobtained in the Guaranteed Time with the Circular Variable Filters of the ISOcamera (CAM-CVF) and with the Short Wavelength Spectrometer (SWS), on board theEuropean Infrared Space Observatory (ISO). Our data shows emission fromamorphous silicate grains from the entire HII region and around the isolatedO9.5V star Theta2 Ori A. The observed spectra can be reproduced by a mixture ofinterstellar silicate and carbon grains heated by the radiation of the hotstars present in the region. Crystalline silicates are also observed in theOrion nebula and suspected around Theta2 Ori A. They are probably ofinterstellar origin. The ionization structure and the distribution of thecarriers of the Aromatic Infrared Bands (AIBs) are briefly discussed on thebasis of the ISO observations.

CERN Document Server

UBVI CCD photometry of NGC 2353 is obtained as part of the "Sejong Open cluster Survey" (SOS). Using the photometric membership criteria we selelct probable members of the cluster. We derive the reddening and distance to the cluster, i.e. E(B-V) = 0.10 +/- 0.02 mag and 1.17 +/- 0.04 kpc, respectively. We find that the projected distribution of the probable members on the sky is elliptical in shape rather than circular. The age of the cluster is estimated to be log(age)=8.1 +/- 0.1, older than what was found in previous studies. The minimum value of binary fraction is estimated to be about 48 +/- 5 percent from a Gaussian function fit to the distribution of the distance moduli of the photometric members. Finally, we also obtain the luminosity function and the initial mass function (IMF). The slope of the IMF is Gamma = -1.3 +/- 0.2.

CERN Document Server

A new particle swarm optimization (PSO) technique for electromagnetic applications is proposed. The method is based on quantum mechanics rather than the Newtonian rules assumed in all previous versions of PSO, which we refer to as classical PSO. A general procedure is suggested to derive many different versions of the quantum PSO algorithm (QPSO). The QPSO is applied first to linear array antenna synthesis, which is one of the standard problems used by antenna engineers. The performance of the QPSO is compared against an improved version of the classical PSO. The new algorithm outperforms the classical one most of the time in convergence speed and achieves better levels for the cost function. As another application, the algorithm is used to find a set of infinitesimal dipoles that produces the same near and far fields of a circular dielectric resonator antenna (DRA). In addition, the QPSO method is employed to find an equivalent circuit model for the DRA that can ...

International Nuclear Information System (INIS)

We present production rates of the two- and three-jet final states for the processes of massive cc/bb quark production in circularly polarized photon-photon collisions, including QCD radiative corrections. Lowest-order cross section, one-loop virtual correction, and gluon emission correction are shown to be of the same order of magnitude for bb quark production at s_#gamma#_#gamma# similar 100 GeV. It is shown that the signal from an intermediate mass Higgs boson is observable at a photon-photon collider, though the statistical significance is substantially reduced with respect to the tree-level calculation. ((orig.)).

British Library Electronic Table of Contents (United Kingdom)

We demonstrate a novel cross-sectional deformation, called the radial corrugation, of multi-walled carbon nanotubes (MWNTs) under hydrostatic pressure. Theoretical analyses based on the continuum elastic approximation have revealed that MWNTs consisting of more than ten concentric walls undergo elastic deformations at critical pressure Formula Not Shown , above which the circular shape of the cross-section becomes radially corrugated. Various corrugation modes have been observed by tuning the innermost tube diameter and the number of constituent walls, which is a direct consequence of the core-shell structure of MWNTs. Cross-sectional views of MWNT under high hydrostatic pressure: elliptic deformation with the mode index n = 2 (left), and radial corrugations with n = 5 (center), and n = 6 ...

British Library Electronic Table of Contents (United Kingdom)

In this work, a pre-cracked semi-circular shaped explosive simulant was loaded using a split Hopkinson pressure bar (SHPB). A high-speed camera was used to capture the deformation and fracture process of the specimen in situ. The digital images were processed using the digital image correlation (DIC) method. Next, full displacement and strain fields were obtained. The displacement vector field shows that the specimen fractured under tensile stress action. The strain field can be used to predict the crack propagation. Results show that the method of combined DIC and SHPB is effective to study the dynamic deformation and fracture behavior of explosive simulants. In addition, the specimen was loaded using a drop weight. The fracture toughness of the specimen was preliminary measured.

British Library Electronic Table of Contents (United Kingdom)

Propanolol is a betablocker drug used in the treatment of arterial hypertension related diseases. In order to achieve an optimal performance of this drug it is important to consider the possible interactions of propanolol with plasma proteins. In this work, we have used several experimental techniques to characterise the effect of addition of the betablocker propanolol on the properties of bovine plasma fibrinogen (FB). Differential scanning calorimeter (DSC), circular dichroism (CD), dynamic light scattering (DLS), surface tension techniques and atomic force microscopy (AFM) measurements have been combined to carry out a detailed physicochemical and surface characterization of the mixed system. As a result, DSC measurements show that propranolol can play two opposite roles, either acting ...

British Library Electronic Table of Contents (United Kingdom)

Objectives: The aim of this study was to evaluate the in vitro behaviour of all-ceramic zirconia molar crowns in regard to different core designs and marginal fit. Methods: Identically shaped methacrylate molars were prepared according to the ceramic restoration directives resulting in a 1-mm deep circular shoulder preparation. They were embedded in polymethylmethacrylate resin after covering their roots with a polyether layer to simulate periodontal mobility. The crown cores were made of yttria-stabilized zirconia veneered with a corresponding veneering ceramic. The crowns were divided into 5 groups (n=8) which differed in core design and cement gap thickness: #1: simple core, 40mm cement; #2: core with minimal occlusal support, 40mm cement; #3: core with optimized cusp support, 40mm ceme...

Science.gov (United States)

This paper presents the experimental results of heat transfer augmentation in an axisymmetric jet impinging normally on a flat plate surface without the requirement of additional pumping power. The present technique of augmentation utilizes only a punched plate with circular holes arranged in a triangular array, fixed parallel to, just in front of the heated target plate. Near the optimum conditions determined, the heat transfer coefficient at the geometrical stagnation point can be increased 4 times. Additional flow visualization study indicates that this augmentation mechanism creates an improved flow field where the punched plate acts as a detached fin, the conductivity of which may be exploited for further augmentation. Besides augmentation, the present investigation foresees the possibility of manipulating the distribution of local heat transfer rate by varying few parameters.

International Nuclear Information System (INIS)

This report summarizes the results of a research programme which involves the development of a laboratory experimental facility for the simulation and study of hydro-thermo-mechanical processes in saturated geomaterials with low permeability. The experimentation involves a synthetic cement based porous material made of cement grout which possesses permeabilities in the range of dense unfractured sandstones or shale. Specially manufactured pore-pressure transducers were installed within the cylindrical block at locations adjacent to a plane free boundary. The block was saturated with the periodic application of a vacuum. In its saturated state the plane boundary of the block was subjected to heating via a circular heater the temperature of which was maintained constant. The resulting pore pressure generation along with temperature at these locations was monitored continuously. The results of a series of experiments are documented and further extensions to the ...

Energy Technology Data Exchange (ETDEWEB)

The electron cyclotron resonance layer in a tokamak, {omega}={omega}{sub c}(r), is not accessible by the extraordinary wave from the low field side, because it is shielded by a cutoff layer. However, a X-mode launched with a nonzero toroidal angle propagates at the cutoff parallel to the magnetic field and has a circular polarization. Therefore it can already at the cutoff layer interact efficiency with electrons via the Doppler shifted resonance. The driven current can be substantially higher than that driven by the second harmonic X-mode. The applicability of this current drive scheme is limited to rather low values of {omega}{sub p}{sup 2}/{omega}{sub c}{sup 2}, but may be of interest for high magnetic field devices. (author)

Energy Technology Data Exchange (ETDEWEB)

The potential profitability of a horizontal borehole drilling program for recovering methane gas in an Alabama coalbed for 6 yr in advance of mining is estimated in the Bureau of Mines report. A cash flow analysis based on estimated capital investments, annual operating costs, and the selling price of methane gas was used to determine the net income and net cash flow for each year of operation. Subsequently, the annual net cash flows were capitalized to determine the discounted cash flow rate of return. Findings indicate that a 25.08-percent interest rate of return on investment could be realized from the sale of methane gas in excess of 3 billion cubic feet during the years 1985 through 1990 at a minesite price of $2.25/per thousand cubic feet.

British Library Electronic Table of Contents (United Kingdom)

Rapid administration of stable iodine is essential for the saturation and subsequent protection of the thyroid gland against the potential harm caused by radioiodines. This paper proposes the Dutch risk analysis that uses an atmospheric dispersion model to calculate the size of the zones around nuclear power plants where radiological thyroid doses for children might be sufficiently high to warrant iodine administration. Dose calculations for possible releases from the nuclear power plants of Borssele (The Netherlands), Doel (Belgium) and Emsland (Germany) are based on two scenarios in combination with a 1-y set of authentic, high-resolution meteorological data. The dimensions of the circular zones were defined for each nuclear power plant. In these zones, with a radius up to 50 km, distrib...

Energy Technology Data Exchange (ETDEWEB)

The interaction of thermal radiation with conduction and convection in thermally developing absorbing, emitting, nongray gas-particulate turbulent suspension flow through a circular tube is investigated. The contribution of thermal radiation is obtained through evaluation of the total hemispherical emittance of the particulate cloud and through evaluation of single band absorptances for molecular gases, modified to account for the interaction with the particles. The governing differential equation is derived as a (nonlinear) energy equation, coupled with integral equations to find the thermal radiation contributions. The energy equation is solved numerically by an implicit finite difference method with an iterative procedure. Qualitative results for Nusselt numbers are shown for a variety and range of parameters, such as optical thickness of particulates and single molecular gas bands, relative gas band position and band width, and temperature ratios (heated as ...

British Library Electronic Table of Contents (United Kingdom)

Purpose To study the chemical modifications induced upon irradiation of solid human insulin at radiosterilization doses and investigate the influence of the absorbed dose on radiolysis. Materials and Methods Volatile radiolytic products were monitored by gas chromatography coupled with mass spectrometry (GC-MS) and non-volatile products by two different high performance liquid chromatography (HPLC) methods: the formation of higher molecular weight proteins was assessed by size exclusion liquid chromatography whereas assays for related compounds and chemical potency tests were carried out using reverse-phase HPLC-UV. Conformational changes were investigated by measurements of circular dichroism. Results After gamma irradiation at 10?kGy, the recovery of insulin was 96.8%; higher molecular w...

CERN Document Server

Mono-layers of stearic and behenic acids deposited with the Langmuir-Blodgett technique, were used as aligning films in nematic liquid crystal cells. During the filling process the liquid crystal adopts a deformed quasi-planar alignment with splay-bend deformation and preferred orientation along the filling direction. This state is metastable and transforms with time into homeotropic once the flow has ceased. The transition is accompanied by formation of disclination lines which nucleate at the edges of the cell. The lifetime of the metastable splay-bend state was found to depend on the cell thickness. On heating, anchoring transition from quasi-homeotropic to degenerate tilted alignment in form of circular domains takes place near the transition to the isotropic phase. The anchoring transition is reversible with a small hysteresis.

Energy Technology Data Exchange (ETDEWEB)

Radial sonic crystals (RSC) are fluidlike structures infinitely periodic along the radial direction that verify the Bloch theorem and are possible only if certain specially designed acoustic metamaterials with mass density anisotropy can be engineered (see Torrent and Sanchez-Dehesa 2009 Phys. Rev. Lett. 103 064301). A comprehensive analysis of two-dimensional (2D) RSC shells is reported here. A given shell is in fact a circular slab with a central cavity. These finite crystal structures contain Fabry-Perot-like resonances and modes strongly localized at the central cavity. Semi-analytical expressions are developed to obtain the quality factors of the different resonances, their symmetry features and their excitation properties. The results reported here are completely general and can be extended to equivalent 3D spherical shells and to their photonic counterparts.

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The human mitochondrial DNA (mtDNA) is a closed circular, 16,569-bp double-stranded DNA, encoding 13 genes whose protein products are subunits of the oxidative phosphorylation system required for synthesis of most of the ATP consumed by eukaryotic cells. Point mutations of the mtDNA that cause multi-tissue, loss-of-energy syndromes, called mitochondrial encephalomyopathies (e.g., MERRF and MELAS), have been identified. In addition, large-scale deletions of the human mtDNA have been identified and are the molecular bases for the neonatal and adolescent onset loss-of-energy syndromes Pearson and Kearns-Sayer, respectively. 5 refs., 1 fig.

UK PubMed Central (United Kingdom)

The effect of reinforcement in the cross-linked poly(propylene fumarate-co-caprolactone diol) thermoset composites based on Kevlar fibres and hydroxyapatite was studied. Cross-linked poly(propylene...Full Text Available

International Nuclear Information System (INIS)

Superconducting Cu-rich composites containing the A-15 compounds V_3Si or V_3Ga were made by the ''Tsuei'' process (melting into ingots followed by cold working and heat treatment). Superconducting transition temperatures of the composites were measured. X-ray diffraction analyses were performed. Microstructures were studied using both the optical metallograph and the scanning electron microscope. For some composites containing V_3Ga, the critical current densities as functions of transverse magnetic field up to 60 kG, and as functions of temperature from 4.2 to 12"0K were measured. It was found that the Tsuei process does not work for the composites containing V_3Si, but works satisfactorily for V_3Ga; reasons are discussed. Relations between measured properties and various metallurgical factors such as alloy compositions, cross-section reduction ratios, and heat treatment are ...

UK PubMed Central (United Kingdom)

In this study, we report the physico-chemical and biological properties of a novel biodegradable composite scaffold made of nano-hydroxyapatite and natural derived polymers of chitosan and carboxymethyl...Full Text Available

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The present invention relates to a method of acidizing a subterranean formation or well bore employing an acidic solution containing a corrosion inhibitor composition comprising an inhibiting effective amount of an acetylenic alcohol, a quaternary ammonium compound, an aromatic hydrocarbon and an antimony compound.

UK PubMed Central (United Kingdom)

Improving the anti-demineralizing/remineralizing and mechanical properties of amorphous calcium phosphate (ACP) composites has been the focus of our recent research. In this study, an ethoxylated...Full Text Available

UK PubMed Central (United Kingdom)

This study compared the effectiveness of collaborative group composition and instructional method on reasoning gains and achievement in college biology. Based on initial student reasoning ability (i.e.,...Full Text Available

Science.gov (United States)

A summary of research conducted during the first year is presented. The research objectives were sought by conducting two tasks: (1) investigation of probabilistic design techniques for reliability-based design of composite sandwich panels, and (2) examin...

UK PubMed Central (United Kingdom)

In this study we determined the composition and biogeochemistry of novel, brightly colored, white and orange microbial mats at the surface of a brine seep at the outer rim of the Chefren mud volcano....Full Text Available

UK PubMed Central (United Kingdom)

The objectives of this study were to quantify the effect of 16 ppm of dietary monensin on milk production and composition of dairy cows, and to investigate factors having a potential impact on this...Full Text Available

International Nuclear Information System (INIS)

... thermal power plants thermal reactors water cooled reactors WATER

CERN Document Server

We provide an algebraic study of the local composite operators A_\\mu A_\

Science.gov (United States)

Surface crystallization and surface-to-bulk ratio in high-level waste glasses.

KoreaScience (Korea)

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International Nuclear Information System (INIS)

This is a preliminary study on the sound absorption properties of two tropical hardwoods, Light Red Meranti and Ramin, and their wood-polymer composites. Sound absorption is measured using a standing wave apparatus. The samples are of one thickness (7 mm) and cut longitudinally. Wood-polymer composites are made by impregnating the samples with methyl methacrylate which is polymerized in situ through #gamma#-irradiation. Both woods and their composites are better sound absorbers at higher sound frequencies. With partial impregnation, the absorption coefficients are improved upon particularly in the region between 1-3 kHz. (author).

International Science & Technology Center (ISTC)

Development of SHS-technologies for SiC, Si3N4 and Ceramic Composites on Their Basis from Rocks

Science.gov (United States)

... interactive surfaces and interfaces, and 3) the more complex a ... carbonate or calcium phosphate with a thin interface ... diameter) for nerve prosthesis. ...

Science.gov (United States)

Moisture ingression was studied in several composite sandwich panels.No observable ingression was

Science.gov (United States)

... The task consisted of determination of the most economical composition of the charge of the cupola furnace of the foundry. 21s was no simple task. ...

Energy Technology Data Exchange (ETDEWEB)

A heat storage compostion comprises sodium sulfate decahydrate as main component, a supercooling inhibitor, and a solid-liquid separation inhibitor. The composition is characterized in that hydraulic calcium sulfate and/or calcium sulfate dihydrate is contained as the solid-liquid separation inhibitor in an amount of 2-15 wt% base on the whole weight of the composition, whereby the solid-liquid separation, i.e. the sedimentation of the anhydrous sodium sulfate during the phase transition, is effectively prevented and the long-term stability is improved. The long-term stabilty of the composition can be more improved by addition of a silcia series of thickener.

KoreaScience (Korea)

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KoreaScience (Korea)

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KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

The Cu- and Ni-based bulk metallic glass matrix composites were fabricated by spark plasma sintering of a mixture of gas-atomized metallic glass powders and ductile brass powders. The brass powders added for the enhancement of plasticity are well distributed in the matrix after consolidation. The matrix of the composite materials remains as a fully amorphous phase after consolidation process. With increasing the brass content, the level of plasticity strain increased, although the level of strength decreased. The successful consolidation of metallic glass matrix composite with high density was attributed to viscous flow in the supercooled liquid state during spark plasma sintering.

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A variety of engineering and experimental applications require primary support structures which are self-centering. High mechanical strength, low-density, carbon fiber/epoxy matrix composite springs are used in unique planar, cylindrical, conical, and spherical configurations to self-center components. The sinusoidal and triangular-shaped composite springs are readily manufactured and assembled into component hardware. Design considerations, flexural strength properties, load bearing and centering data plus procedures for the manufacture of composite springs are presented.

Science.gov (United States)

A new high capacity anode composite based on mesoporous silicon is proposed. By virtue of a structure that resembles a pseudo one-dimensional phase, ...

British Library Electronic Table of Contents (United Kingdom)

The physics and technology of a new class of efficient composite piezoelectrics are described. This material combines nanostructured and micropiezoelectric matrix composites. They consist of a polymer matrix, an insulating nanodimensional phase, and a microdimensional piezoelectric phase. It is shown that the nanostructuring of the near-surface region of polymer-PZT piezoelectric composites greatly improves their piezoelectric, mechanical, and electromechanical characteristics. A plausible mechanism underlying this effect is suggested.

International Nuclear Information System (INIS)

X-ray scattering methods suitable for the investigation of the morphology and chemical composition of self-organized quantum dots and quantum wires are reviewed. Their application is demonstrated in experimental examples showing that a combination of small angle X-ray scattering with high-resolution X-ray diffraction can reveal both the shape and the chemical composition of the self-organized objects. (author)

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The gas composition of recent thermal waters is in perfect conformity with their geologic-tectonic positions. The composition of gas-liquid inclusions in the basic-hyperbasic xenoliths of basaltoid lavas depends on the depth from which xenoliths are supplied. (The depth is determined by using the methods of geological thermobarometers). By comparing available data the conclusion was drawn that the gas compositions of thermal waters reflect the depth of generation of deep fluid which heats them and depends on the penetration depth of the fluid-conducting fissure zones.

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Airbag pressure vessels for the north-American market mainly are made by forging and by the use of steel alloys. In Europe aluminum alloys are common and the manufacturing process is extrusion of circular blanks - made from cold rolled plates - in a form applying a 100 t press at room temperature. Then by heat treatment the strength/hardness of the material is properly adjusted and after that the pressure vessel parts have to be continuously inspected with an inspection and handling cycle time of 3 s. Inspection of the axis-symmetric parts is asked for surface breaking extrusion defects as well as for surface parallel delaminations in the bulk volume. Furthermore, the material strength is a quality characteristic that has to be nondestructively registered and documented. The inspection is performed by eddy current probes and an EMAT, of which the eddy current impedance measurements are used for surface breaking extrusion defect detection and sizing (single ...

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Characteristics of pressure drop and heat transfer have been investigated for a lithium single-phase flow and a helium-lithium two-phase flow in a horizontal conducting circular channel in the presence of a uniform transverse magnetic field up to 1.4 T as related to the lithium cooling for magnetic-confinement fusion reactors. By the application of the magnetic field to the lithium single-phase flow, remarkable heat transfer enhancement has been observed at the top wall due to the suppression of the mixed convection occurring in the low Peclet number range, while appreciable heat transfer deterioration appeared in the high Peclet number range. It has been confirmed that the helium-lithium two-phase flow can reduce the high magnetohydrodynamic (MHD) pressure drop in a lithium single-phase flow, and it can provide much better heat transfer performance than that in a helium single-phase flow. In the presence of the magnetic field, heat transfer coefficient drastically ...

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X-ray magnetic circular dichroism (XMCD) was used to probe the existence of induced magnetic moments in yttrium iron garnet (YIG) films in which yttrium is partly substituted with lanthanum, lutetium or bismuth. Spin polarization of the 4d states of yttrium and of the 5d states of lanthanum or lutetium was clearly demonstrated. Angular momentum resolved d-DOS of yttrium and lanthanun was shown to be split by the crystal field, the two resolved substructures having opposite magnetic polarization. The existence of a weak orbital moment involving the 6p states of bismuth was definitely established with the detection of a small XMCD signal at the Bi M{sub 1}-edge. Difference spectra also enhanced the visibility of subtle changes in the Fe K-edge XMCD spectra of YIG and {l_brace}Y, Bi{r_brace}IG films. Weak natural X-ray linear dichroism signatures were systematically observed with all iron garnet films and with a bulk YIG single crystal cut parallel to the (1 1 1) ...

British Library Electronic Table of Contents (United Kingdom)

The integration of the environmental problem in the design of industrial products leads us to incorporate vegetal fibres and recycled polymers into composite materials. The aim of this work is to study the behaviour and the environmental interest of a recycled PP/hemp fibre after several injection cycles. The mechanical and rheological behaviour of recycled PP/hemp composite was first studied by using tensile, dynamical mechanic analysis and rheological measurements. Then, to better understand the influence of the recycling, a morphology study was carried out on composites by using optical and electron microscopy. Finally, we investigated the environmental advantages of our composite thanks to a simplified environmental assessment. Our results highlighted the environmental interest of usin...

British Library Electronic Table of Contents (United Kingdom)

The age hardening behavior of Al-4.5%Cu alloy composite reinforced with zircon sand particulates and produced by stir casting route has been investigated in different quenching media viz, water, oil, and salt brine solution (7wt%). Optical microscopy of the as cast alloy composite indicates that the matrix of the composite has the cellular structure. Copper rich CuAl2 precipitates have been found near particle matrix interface. The results of ageing demonstrate that the microhardness of age hardenable Al-Cu based alloy composites depend on the quenching medium in which they are heat treated. Salt brine quenching is faster as compared to water and oil, even if higher strength is obtained but cannot be used for complex shapes and thin sections where oil quenching is the alternative due to mi...

International Nuclear Information System (INIS)

This study is an attempt to measure the quantities of elements in a composite by irradiating that composite with #gamma#-rays of various energies and detecting the transmitted radiation through the composite. A previous knowledge of the number of the elements and their attenuation coefficients is required. The quantities are calculated by solving the matrix of a linear system of equations. A computer program was developed to select the best combinations of the available energies. Five criteria were established to determine these energy combinations: (i) the determinant of the attenuation coefficient matrix; (ii) the condition number, (iii) the number of times the solution of the matrix leads to acceptable results; (iv) the indicator, (a new concept); (v) the standard deviations of the results. The intended application of this technique in medicine is to measure the bone mineral content of the skeleton. An examination of the ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Poly(butylene terephthalate) (PBT) composites containing multiwalled carbon nanotubes (MWCNTs) were prepared using a melt-blending process and used to examine the effects on the composite structure and properties of replacing PBT with acrylic acid-grafted PBT (PBT-g-AA). PBT-g-AA and multihydroxyl-functionalized MWCNTs (MWCNTs-OH) were used to improve the compatibility and dispersibility of the MWCNTs within the PBT matrix. The composites were characterized morphologically using transmission electron microscopy, and chemically using Fourier transform infrared, solid-state 13C NMR and UV-visible absorption spectroscopy. The antibacterial and electrical conductivity properties of the composites were also evaluated. MWCNTs or MWCNTs-OH enhanced the antibacterial activity and electric...

Energy Technology Data Exchange (ETDEWEB)

The effect of the coated composite surface of particles on the mechanical properties of the powder bed was investigated. Polyethylene-silica surface composite powder was prepared at several coating ratios with Hybridizer. Various tests on mechanical properties of the powder bed were carried out with the prepared powder, and the following results were obtained: The ultimate tensile strength depends only on the cohesive force between particles, and the contact probability model of composite particles led to good agreement between the experimental and calculated values. The coefficient of internal friction and cohesive shear strength were influenced due to the interlocking effect of the surface roughness of composite particles. The effects of coating particles became small with dynamic properties like angle of repose. It is possible to control the mechanical properties in a step wise fashion by changing ...

British Library Electronic Table of Contents (United Kingdom)

To improve the friction and wear behavior of carbon fabric reinforced polymer composites (CFRP), nano-SiO2 was deposited on the fabric surface. The friction and wear behavior of the resulting composites were investigated on a model ring-on-block test rig. Experimental results revealed that fiber surface treatment contributed to largely improve the tribological properties of the CFRP composites. Scanning electron microscope (SEM) investigation showed that the worn surface of the surface modified CFRP composite was smoother under given load and sliding rate. Field emission scanning electron microscopy (FESEM), FTIR and X-ray photoelectron spectroscopy (XPS) studies of the carbon fiber surface showed that nanostructured Sio2 thin film can be obtained by SiO2 sols deposition, which improved th...

International Nuclear Information System (INIS)

Composite materials of synthetics (based on monomers, oligomers and thermoplastics) and of natural polymers (wood and other fibrous cellulosics) prepared by radiation processing, offer valuable structural materials with enhanced coupling forces between the components. The applied polymer chemistry of such composites shows several common features with that of radiation grafting, e.g. the polymerization rate of oligomer-monomer mixtures in wood remains in most cases proportional to the square-root of the initiating dose-rate, just as in the simultaneous grafting, demonstrating that the chain termination kinetics remain regularly bimolecular in the corresponding dose-rate ranges. In the processing experiences of such composites, low dose requirement, easy process-control, and good technical feasibility have been found for composites of wood with oligomer-monomer mixtures, for coconut fibres with ...

Energy Technology Data Exchange (ETDEWEB)

The Rader Member contains coarse allochthonous carbonate debris deposited basinward of a approx. = 500-m high angle of repose foreslope. Sheet-like megabreccias with internal channel fills up to 35 m thick are traceable 6.5 km along the reef escarpment (depositional strike) and extend 13 km southeast from the toe of slope into the Delaware basin. A prominent erosion surface at the base of the megabreccias may represent a major basin-sloping unconformity. At maximum thickness (65 m) of exposed Rader, three lithologic units are recognized in upward succession: (1) fine-grained, bioturbated limestones interbedded with fine-grained, laminated sandstones; (2) matrix- and clast-supported megabreccias comprised of chaotically oriented limestone blocks (up to 10 m across) with a fine-grained sandstone matrix; and (3) coarse to fine-grained carbonate turbidites interbedded with sandstones. The megabreccias truncate 30 m of section within 2.5 km of the shelf edge, completely ...

Energy Technology Data Exchange (ETDEWEB)

A downhole seismic source which can output continuous waves having arbitrary waveforms was developed. The development was targeted to make tomographic exploration purposed to evaluate geological properties of a ground bed before and after constructing a building in a ground several hundred meters deep from the ground surface. The source is considered to be used in an environment consisting of soft rocks or more robust rocks and having no casing. It can be used in a well hole having a diameter of 100 mm, is capable of measuring P and S waves in a distance between well holes of up to 100 m, can be used at a depth of up to 500 m, and can output waveforms having seismic source spectra of up to 1000 Hz. An oscillation actuator using laminated piezo-electric elements was used for the oscillation element. The seismic source consists of a hydraulic device to clamp the equipment onto hole walls, piezo-electric elements as the oscillation element, and an inertia weight for ...

Science.gov (United States)

Within the Williston basin, thickness variations of the Prairie Formation are common and are interpreted to originate by two processes: differential accumulation of salt during deposition and differential removal of salt by dissolution. Unambiguous evidence for each process is rare because the Prairie/Winnipegosis interval is seldom cored within the US portion of the basin. Therefore, indirect methods, using well logs, provide the principal method for identifying characteristics of the two processes. The results of this study indicate that the two processes can be distinguished using correlations within the Prairie Formation. Several regionally correlative brining-upward and probably shoaling-upward sequences occur within the Prairie Formation. Near the basin center, the lowermost sequence is transitional with the underlying Winnipegosis Formation. This transition is characterized by thinly laminated basal carbonates that become increasingly interbedded with ...

International Nuclear Information System (INIS)

Spherical nanostructured Si/C composite was prepared by spray drying technique, followed by heat treatment, in which nanosized silicon and fine graphite particles were homogeneously embedded in carbon matrix pyrolyzed by phenol formaldehyde resin. Cyclic voltammetry tests showed two pairs of redox peaks corresponding to lithiation and delithiation of Si/C composite. The Si/C composite exhibited a reversible capacity of 635 mAh g"-"1 and good cycle performance used in lithium ion batteries. To improve cycle performance of this Si/C composite further, the carbon-coated Si/C composite was synthesized by the second spray drying and heat treatment processing. The cycle performance of carbon-coated Si/C composite was improved significantly, which was attributed to the formation of stable SEI passivation layers on the outer surface of carbon shell which protected the ...

International Nuclear Information System (INIS)

The composite of doped lanthanum gallate (La_0_._9Sr_0_._1Ga_0_._8Mg_0_._2O_2_._8_5, LSGM) and doped ceria (Ce_0_._8Sm_0_._2O_1_._9, CSO) was investigated as an electrolyte for solid oxide fuel cell (SOFC). The LSGM-CSO composite was examined by X-ray diffraction (XRD) and impedance spectroscopy. It was found that the sintered LSGM-CSO composite contains mainly fluorite CeO_2 phase and a minority impurity phase, Sm_3Ga_5O_1_2. The LSGM-CSO composite electrolyte shows a small grain boundary response in the impedance spectroscopy as compared to LSGM and CSO pellets. The composite electrolyte exhibits the highest conductivity in the temperature range of 250-600 "oC, compared to LSGM and CSO. The LSGM-CSO composite can be expected to be an attractive intermediate temperature electrolyte material for solid oxide fuel cells.

Energy Technology Data Exchange (ETDEWEB)

MmMg{sub 12}-Ni amorphous or nanocrystalline composites (Mm: Ce-rich mischmetal) were prepared through the ball-milling method, and their electrochemical hydrogen storage performance was investigated and compared with that of ball-milled CeMg{sub 12}-Ni composites. It was found that the ball-milled MmMg{sub 12}-Ni composites had larger initial discharge capacities and better high rate dischargeability. Analysis of electrochemical impedance spectra (EIS) shows that the reaction resistance and hydrogen diffusion resistance of the ball-milled MmMg{sub 12}-Ni composites are lower as a result of the decrease in Ce content, and thus can contribute to the larger discharge capacity and better high rate dischargeability. Additionally, the cycle performance of the ball-milled MmMg{sub 12}-Ni composites is better than those of the ball-milled CeMg{sub 12}-Ni composites. ...

Energy Technology Data Exchange (ETDEWEB)

In order to investigate the role of amorphous SiO{sub 2} particles in corrosion and wear resistance of Ni-based metal matrix composite alloying layer, the amorphous nano-SiO{sub 2} particles reinforced Ni-based composite alloying layer has been prepared by double glow plasma alloying on AISI 316L stainless steel surface, where Ni/amorphous nano-SiO{sub 2} was firstly predeposited by brush plating. The composition and microstructure of the nano-SiO{sub 2} particles reinforced Ni-based composite alloying layer were analyzed by using SEM, TEM and XRD. The results indicated that the composite alloying layer consisted of {gamma}-phase and amorphous nano-SiO{sub 2} particles, and under alloying temperature (1000 deg. C) condition, the nano-SiO{sub 2} particles were uniformly distributed in the alloying layer and still kept the amorphous structure. The corrosion resistance of ...

International Nuclear Information System (INIS)

For several decades, ceramic matrix composite have been attracted attention in advanced structural and tribological applications. Advanced structural ceramics are presently used in diverse tribological applications such as tips for ballpoint pens, precision instrument bearings and cutting tools inserts. Design and selection of ceramics for these applications require reliable data on the effects of temperature, load and environment on the tribological behavior of these ceramics. In the present work, #alpha#-sialon matrix composites reinforced with different amounts of #beta#-sialon fibers were produced with the aim of improving their toughness to increase the industrial applications. The wear properties of #alpha#-sialon matrix composites were evaluated by carried out wear tests using a pin-on-disk tribometer under dry conditions. The #alpha#-sialon matrix composites were manufactured by slip casting and ...