International Nuclear Information System (INIS)

This paper discusses the mechanisms of gas breakdown at low values of pressure and inter-electrode gap, i.e. in the vicinity of the Paschen minimum. In this area of pressure and inter-electrode gap values, breakdown occurs either through gas or vacuum mechanisms, and also the so called anomalous Paschen effect appears. Electrical breakdown of electropositive, electronegative and noble gases has been investigated theoretically, experimentally and numerically. Based on the results obtained, regions in which particular breakdown mechanisms appear have been demarcated. Special attention has been devoted to the anomalous Paschen effect as well as to the avalanche vacuum breakdown mechanism.

International Nuclear Information System (INIS)

The accurate prediction of local hot spot during normal operation is important to ensure core thermal margin in a very high temperature gas-cooled reactor because of production of its high temperature output. The active cooling of the reactor core determining local hot spot is strongly affected by core bypass flows through the inter-column gaps between graphite blocks and the cross gaps between two stacked fuel blocks. The bypass gap sizes vary during core life cycle by the thermal expansion at the elevated temperature and the shrinkage/swelling by fast neutron irradiation. This study is to investigate the impacts of the variation of bypass gaps during core life cycle as well as core restraint mechanism on the amount of bypass flow and thus maximum fuel temperature. The core thermo fluid analysis is performed using the GAMMA+ code for the PMR200 block-core design. For the analysis ...

Science.gov (United States)

An estimate of the undercounted electrostatic energy terms in local-density-functional total-energy calculations for nonmetallic systems with separated electron-hole pairs is used to derive a simplified correction to density-functional - theory band gaps. The correction is evaluated for Ne, Ar, Kr, LiF, NaCl, CsCl, MgO, CaS, BaS, C, AlP, and Si. The band-gap errors are reduced from 40-50% to 10-15% for most of the systems studied. Conduction-band corrections are shown to be nearly as large as valence-band corrections in free-electron-like semiconductors. 28 references, 1 figure.

International Nuclear Information System (INIS)

Uniform and transparent thin films of Zn_1_-_xCo_xO (0 #=# 0.035, CoO (cubic) was detected as the secondary phase. Influence of Co addition on the volume fraction of grain boundaries has been interpreted. Increase in Co content in the range 0 #<=# x #<=# 0.10 led to quenching of near-band edge and blue emissions, decrease in band gap energy (E_g) from 3.36 eV to 3.26 eV, decrease in film thickness and refractive index and an increase in extinction coefficient of Zn_1_-_xCo_xO thin films. The change in nature of stress from compressive to tensile with lower to higher doping of Co is corroborative with the angular peak shift of (002) plane of ZnO lattice. An overall increase in microhardness of Zn_1_-_xCo_xO thin films up to x = 0.05 is attributed to change in microstructure and evolution of secondary phase and as the secondary phase separates out the overall stress is released leading to lowering of hardness after this concentration. ...

Science.gov (United States)

flow separation occurred at the junction of the tip fin and the fuselage. ...... Systems, presented at the AGARD Guidance and Control and Flight Mechanics ...

Energy Technology Data Exchange (ETDEWEB)

A continuous-flow filter/concentrator for separating and/or concentrating particles in a fluid is disclosed. The filter is a three-port device an inlet port, an filter port and a concentrate port. The filter separates particles into two streams by the ratio of their dielectrophoretic mobility to their electrokinetic, advective, or diffusive mobility if the dominant transport mechanism is electrokinesis, advection, or diffusion, respectively.Also disclosed is a device for separating and/or concentrating particles by dielectrophoretic trapping of the particles.

British Library Electronic Table of Contents (United Kingdom)

A mechanical model with local resonators is proposed as an acoustic metamaterial that exhibits an unusual frequency-dependent effective stiffness. If treated as an equivalent elastic solid, its effective Young's modulus can become unbounded or vanishingly small at two respective frequencies. Moreover, in a certain frequency range, the effective Young's modulus would become negative, resulting in a band gap that coincides with this frequency range. The wave attenuation behavior and mechanism are studied through numerical simulations on the acoustic metamaterial model. The capability of the metamaterial to selectively block or filter unwanted waves is demonstrated by a numerical simulation example.

Energy Technology Data Exchange (ETDEWEB)

The magnetic fluid is a colloidal suspension of magnetite in kerosene, prepared by a low-cost process. Separation is accomplished in an open trough filled with magnetic fluid. A magnetic field is established in the fluid, by energizing an electromagnet having poles on each side of the trough. Due to the design of the magnet poles and air gaps, the magnetic field is strongest at the bottom, about 10,000 oersteds, and uniformly decreases in strength to about 2000 oersteds at the top of the fluid. Therefore, the magnetic field gradient increases with depth. The magnetic force attracts the entire separation medium (magnetic fluid) creating a reaction force of equal magnitude and acting in the opposite direction. This reaction created within a magnetic fluid/magnetic field combination is called a magnetic levitation force. It increases with the field strength. In this case because the magnetic field is strongest at the bottom of ...

Energy Technology Data Exchange (ETDEWEB)

The optoelectronic and excitonic properties in a series of linear acenes are investigated using range-separated methods within time-dependent density functional theory (TDDFT). In these highly-conjugated systems, we find that the range-separated formalism provides a substantially improved description of excitation energies compared to conventional hybrid functionals, which surprisingly fail for the various low-lying valence transitions. Moreover, we find that even if the percentage of Hartree-Fock exchange in conventional hybrids is re-optimized to match wavefunction-based CC2 benchmark calculations, they still yield serious errors in excitation energy trends. Based on an analysis of electron-hole transition density matrices, we also show that conventional hybrid functionals overdelocalize excitons and underestimate quasiparticle energy gaps in the acene systems. The results of the present study emphasize the importance of ...

International Nuclear Information System (INIS)

Two new identical insertion devices have been designed for the Daresbury SRS. They are 2T permanent-magnet multipole wigglers that will provide high flux in the X-ray region. This paper describes the magnetic and mechanical design of the arrays of steel pole pieces and permanent-magnet blocks. Also given is the engineering design of the support structure that will cope with the very large forces present while maintaining high levels of precision in gap setting and parallelism. The engineering design has been fully assessed using finite-element techniques to predict the deflections of critical parts of the structure. These two devices are due to be installed into the SRS by the end of 1998.

UK PubMed Central (United Kingdom)

A major goal in perceptual neuroscience is to understand how signals from different sensory modalities are combined to produce stable and coherent representations. We previously investigated interactions...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

In this report, the quantitative relation between the height equivalent to a theoretical plate (HETP) and the size of ion exchange resin is studied by enriching lithium isotopes with high pressure ion exchange displacement chromatography. The dependence of HETP on the size of the resin can be expressed as H = C x (anti r)sup( ) in which = 2.4 and it is found that Snyder's equation is suitable for such a system of isotope separation as may be explained by the simple displacement mechanism.

CERN Document Server

We present first worldline numerical results for the nontrivial interplay between geometry and temperature dependencies of the Casimir effect. We show that the temperature dependence of the Casimir force can be significantly larger for open geometries (e.g., perpendicular plates) than for closed geometries (e.g., parallel plates). For surface separations in the experimentally relevant range, the thermal correction for the perpendicular-plates configuration exhibits a stronger parameter dependence and exceeds that for parallel plates by more than an order of magnitude at room temperature. This effect can be attributed to the fact that the fluctuation spectrum for closed geometries is gapped, inhibiting the thermal excitation of modes at low temperatures. By contrast, open geometries support a thermal excitation of the low-lying modes in the gapless spectrum already at low temperatures.

British Library Electronic Table of Contents (United Kingdom)

Abstract Phase-separation dynamics are investigated by SALS in aqueous MC solutions in the presence of 5% NaCl, promoted by a quench temperature. The observed scattering peak indicates that the phase separation occurs by the SD mechanism, leading to a bicontinuous structure. A semilog plot of I(q) against time in the early stage of SD gives a straight line, but the position of qmax varies; also, a Cahn-Hilliard plot indicates that diffusive processes dominate and the data can be described by linear CHC theory. Dapp shows a kinetic dependency on the quench temperature. The spinodal temperature of the sample is 41-C. In the late stages, S(q,t) collapses into a universally time-independent curve.

Science.gov (United States)

In 1991, the Peacock Hill Working Group provided the field of emotional and behavioral disorders (EBD) a roadmap for improving the quality of services provided to students with EBD. The working group considered issues at every level of the educational system, from the classroom to federal policy. Although many strides have been made in the past 20 years regarding the education and treatment of students with EBD, the gap has persisted between empirically validated practices and the classroom routines of teachers serving students from this population. In the authors' view, the field of EBD would benefit greatly from conceptual and empirical developments to improve the mechanisms required to bring science to the classroom. Using the theoretical underpinnings of implementation science, the authors describe a transactional model for integrating research, policy, and practice to close the research-to-practice gap. Recommendations ...

Energy Technology Data Exchange (ETDEWEB)

Degradation reactions of a nylon 6 battery separator material have been studied in 4-34% aqueous KOH electrolytes at 35/sup 0/-110/sup 0/C. In a Ni/Cd cell, this degradation involves a slow hydrolysis reaction followed by fast electrochemical oxidations of the hydrolysis reaction products. Arrhenius activation energy of the hydrolysis reaction in 34% KOH was 20.0 +- 0.3 kcal/mole. A plot of the hydrolysis rate at 100/sup 0/C vs. hydroxyl ion concentration gave a rate maximum at about 16% KOH, and the mechanism for this effect is discussed. Electrochemical oxidations of the hydrolysis product, 6-aminocaproate ion, appear to proceed rapidly in several sequential steps at a nickel oxide electrode. In a Ni/Cd cell, the combination of nylon separator hydrolysis followed by electrochemical oxidation of the products can seriously degrade the battery lifetime. The rate of the hydrolysis of nylon 66 separator ...

International Nuclear Information System (INIS)

The repulsive Casimir force is expected as a force which enables to levitate small objects such as machine parts used in Micro Electro Mechanical Systems (MEMS), and superlubricity in MEMS may be realized by this levitation. We study the Casimir force between a gold sphere and a nanocomposite sheet containing many nickel nanoparticles. In particular, we focus on the dependence of the Casimir force on the separation between the gold sphere and the surface of the nanocomposite sheet. The Casimir force changes from the attractive force to the repulsive force as the separation increases. The strength of the repulsive force is, however, too small to levitate MEMS parts.

British Library Electronic Table of Contents (United Kingdom)

Nano- and microstructured surfaces are known to impact on the binding and differentiation of cells, but the detailed basic understanding of the underlying regulatory mechanisms is still scarce, which impedes the rational design of smart biomaterials. Towards a comprehensive analysis of the interplay between topographical parameters such as feature design and lateral and vertical dimensions we here report on a combinatorial screening approach, BioSurface Structure Array (BSSA) of test squares each with a distinct topography. Using such BSSA libraries of 504 topographically distinct surface structures, we have identified combinations of size, gap and height of structures which enhance mineralization as well as the expression of osteogenic markers of a preosteoblastic murine cell line. This g...

British Library Electronic Table of Contents (United Kingdom)

A novel continuous laminar shear structuring crystallizer with a suitable cooling system was designed and built. This is a new method to continuously crystallize edible fat in the desirable polymorphic form from the melt while being uniformly sheared.The machine consists of four main sections: Feed unit, shearing mechanism, cooling system and power unit. In each of these sections specific design considerations are taken into account which makes the process controllable and continuous. The shearing unit is made of two concentric cylinders. The internal cylinder is stationary and has a cooling system inside for temperature control. The outer cylinder rotates to produce a uniform shear in the sample fluid placed in the 1.5mm gap between the cylinders. The sample's feed rate is controlled whil...

CERN Document Server

A recurrent idea in the study of complex systems is that optimal information processing is to be found near bifurcation points or phase transitions. However, this heuristic hypothesis has few (if any) concrete realizations where a standard and biologically relevant quantity is optimized at criticality. Here we give a clear example of such a phenomenon: a network of excitable elements has its sensitivity and dynamic range maximized at the critical point of a non-equilibrium phase transition. Our results are compatible with the essential role of gap junctions in olfactory glomeruli and retinal ganglionar cell output. Synchronization and global oscillations also appear in the network dynamics. We propose that the main functional role of electrical coupling is to provide an enhancement of dynamic range, therefore allowing the coding of information spanning several orders of magnitude. The mechanism could provide a microscopic neural basis for ...

British Library Electronic Table of Contents (United Kingdom)

As lithium battery technology sets out to bridge the gap between portable electronics and the electrical automotive industry, cathode materials still stand as the bottleneck regarding performances. In the realm of highly attractive polyanion-type structures as high-voltage cathode materials, the sulfate group (SO4)^2^- possesses an acknowledged superiority over other contenders in terms of open circuit voltage arising from the inductive effect of strong covalent S-O bonds. In parallel, novel lithium insertion mechanisms are providing alternatives to traditional intercalation, enabling reversible multi-electron processes securing high capacities. Combining both of these advantageous features, we report here the successful electrochemical reactivity of copper sulfate pentahydrate (CuSO4.5H2O...

International Nuclear Information System (INIS)

Monolithic SiAlON ceramics are hard and brittle with little possibility for property design, but multi-phase SiAlON ceramics offer great scope for controlling microstructural development and desired properties. The ceramics can also be reinforced by separate additions of other hard, refractory compounds. The toughness in all these SiAlON composites can be increased by several mechanisms, and the best effect is reached if they are combined. When glassy phase is present, crack paths are affected by the strains caused by different thermal expansion of the glassy phase and the crystals and also by the interface properties. The crystal shape influence toughness, especially pronounced is the effect of the elongated #beta#- grains. Different toughening mechanisms are achieved by separately added reinforcement phases. The hardness is raised by the presence of #alpha# SiAlON and other hard constituents, such as ...

CERN Document Server

A survey of various mechanisms for particle emission in hydrodynamics is presented. First, in the case of sudden freeze out, the problem of negative contributions in the Cooper-Frye formula and ways out are presented. Then the separate chemical and thermal freeze out scenario is described and the necessity of its inclusion in a hydrodynamical code is discussed. Finally, we show how to formulate continuous particle emission in hydrodynamics and discuss extensively its consistency with data. We point out in various cases that the interpretation of data is quite influenced by the choice of the particle emission mechanism.

Medline Plus

... the pulmonary vein and because there's a gap, electricity is going across the ablation line and capturing ...

DEFF Research Database (Denmark)

Udgivelsesdato: 2009

CERN Document Server

2000-003 Wire pad chambers (WPC) have been proposed for the outer Region 4 of the LHCb Muon System. These are double gap MWPCs with small wire spacing allowing to obtain 99% detection efficiency in a 20 ns time window. The chambers have a rectangular shape with the vertical dimension from 20 cm in Station 1 to 30 cm in Station 5. The horizontal dimensions will be different with the maximal size of 3 meters in Station 5. The wires are in the vertical direction. The short wire length allows to use small wire spacing needed for high time resolution. Also, this helps to obtain the uniform gas gain over the whole chamber area. The WPC has one row of the wire pads formed by grouping wires in separate readout channels. Four WPC prototypes have been built at PNPI and tested in the PS beam at CERN. Here we report on the results from these tests. Also, the results of simulation of the WPC performance are presented.

Energy Technology Data Exchange (ETDEWEB)

When a metallic alloy is quenched into a miscibility gap, a mixture of two phases develops, whose domain structure then coarsens because of the interfacial energy between the two phases. This spatial arrangement of the domains and the rate at which they evolve may be strongly influenced by elastic interactions. In a recent paper, the authors described a method for simulating the effect of anisotropic elastic interactions in a two-dimensional Ising model of a cubic alloy, using Kawasaki dynamics with the elastic interactions represented by a long-range two-body interaction potential. Here they present the results of such simulations at various temperatures, alloy compositions and misfits (by misfit they mean the difference in size between the two kinds of atom), exhibiting snapshots both of the microscopic configurations (corresponding to experimental measurements using transmission electron microscopy) and of their squared Fourier transforms (corresponding to ...

Energy Technology Data Exchange (ETDEWEB)

A study has been made of the interaction between graphitized thermal carbon-black and cyclodextrins and a series of 28 derivatives of benzene (benzene, alkyl-, isoalkyl-, dialkyl-, trialkylbenzenes, vinyl-, and allyl-benzene). The specific retention volumes form the basis for a discussion of the mechanism of interaction and drawing conclusions for the practical separation of isomeric compounds. (orig.).

International Nuclear Information System (INIS)

Heat transfer augmentation by straight grid spacers in rod bundles is studied for single phase flow and for post critical heat flux dispersed flow. The heat transfer effect of swirling grid spacers in single phase flow is also examined. Governing heat transfer mechanisms are analyzed, and predictive formulations are established. For single phase flow, the local heat transfer at a straight spacer and at its upstream or downstream locations are treated separately. 18 refs.

International Nuclear Information System (INIS)

In this paper a study is made of the structure and mechanical properties of the #beta# alloy system Ti-Mo-Zr-Sn (the composition of which is equivalent to the #beta# III alloy used abroad) containing different amounts of carbon. Study of the #beta#-titanium alloy containing 0.1% C revealed the presence of particles of titanium carbide. Separation of the titanium carbide promotes a reduction in impact strength, an increased tendency toward cold shortness, and poorer workability. (author).

Energy Technology Data Exchange (ETDEWEB)

Two rapidly solidified powders with compositions Al-6.7 wt.% Fe-5.9 wt.% Ce and Al-6.2 wt.% Fe-5.9 wt.% Ce-1.63 wt.% Si were separated into -32 [mu]m and +32 to -63 [mu]m size fractions. Powders from both size fractions were extruded at 500 C. For comparison purposes, extrusion at a lower temperature of 400 C was also performed. In this investigation, tensile property evaluation indicated that processing of finer size fractions at high temperature offers no advantages in terms of the tensile properties but is advantageous in terms of improving the fracture toughness of alloy B. These observations underline the importance of the stability of powder microstructure during thermomechanical processing for the development of optimum mechanical properties. (orig.)

British Library Electronic Table of Contents (United Kingdom)

A novel microcapsule adsorbent for separation of uranium from phosphoric acid solutions was developed by immobilizing the di(2-ethylhexyl) phosphoric acid-?trioctyl phosphine oxide extractants in the polymeric matrix of calcium alginate. Physical characterization of the microcapsules was accomplished by scanning electron microscopy and thermogravimetric techniques. Equilibrium experiments revealed that both ion exchange and solvent extraction mechanisms were involved in the adsorption of Formula Not Shown ions, but the latter prevailed in a wider range of acid concentration. According to the results of kinetics study, at low acidity level, the rate controlling step was slow chemical reaction of Formula Not Shown ions with the microdroplets of extractant, whereas it changed to intraparticle...

British Library Electronic Table of Contents (United Kingdom)

Abstract A novel and convenient protocol for the preparation of an open-tubular column coated with chitosan-silica hybrid using chitosan and silane-coupling agent (-glycidoxy-propyltrimethoxysilane) was developed for CEC, in which, chitosan was covalently bonded to the inner wall of a fused-silica capillary using -glycidoxy-propyltrimethoxysilane as a cross-linking agent. The stationary phase was hydrophilic due to the chitosan-silica hybrid with abundant amine and hydroxyl functional groups. The chromatographic characteristics of the column were evaluated by the separation of some organic acids and inorganic anions. The column showed good selectivity for nucleotides, aromatic acids, and inorganic anions. The mechanism for the separation of these compounds was primarily based on the hydrop...

Energy Technology Data Exchange (ETDEWEB)

In order to optimize the performance of molecular organic electronic devices it is important to study the intermolecular density of states and charge transport mechanisms in the environment of crystalline organic material. Using this approach in Field Effect Transistors (FETs) we show that material purification improves carrier mobility and decreases density of the deep localized electronic state. We also report a general exponential energy dependence of the density of localized states in a vicinity of the mobility edge (Fermi energies up to approx7 times higher than the thermal energy (kT)) in a variety of the extensively purified molecular organic crystal FETs. This observation and the low activation energy of the order of approxkT suggest that molecular structural misplacements of the sizes that are comparable with thermal molecular modes rather than impurity deep traps play a role in formation of these shallow states. We find that the charge carrier mobility in ...

Energy Technology Data Exchange (ETDEWEB)

This paper presents the technical and economic studies performed by CEMIG, Companhia Energetica de Minas Gerais, Brazil, concerning the use of closing resistor in its extra-high voltage (EHV) breakers. The analysis emphasizes the advantages which could be achieved with the elimination of the resistor as far as costs and reliability are concerned. This evaluation was motivated by two 500 kV breaker failures resulting from the breakdown of the closing resistor operation mechanism. These occurrences resulted in operative restriction for CEMIG EHV system. The analysis demanded a review of the capability criteria of silicon carbide (Si C) gap arresters, which are still greatly used in CEMIG EHV System, and of the procedures to be applied when carrying out the transient studies. The investigation resulted in the prompt removal of closing resistors from circuit breakers in CEMIG extra-high voltage system generating an economy of approximately U$ ...

Energy Technology Data Exchange (ETDEWEB)

A theoretical model, which describes subband gap photoexcitation involving localized electronic states, was developed. The escape probability of a charge carrier trapped in a localized state is considered via Poole-Frenkel, direct tunneling, or phonon-assisted tunneling processes, as competing escape mechanisms. Photoelectrochemical experiments were performed on the passive films formed on zirconium and amorphous iron-zirconium alloys and on pure HfO/sub 2/ films and HfO/sub 2/ films implanted with varying concentrations of xenon. These films were found to possess some degree of disorder depending on the substrate, the thickness of the film, and the extent of implantation. The spectral dependence of the photocurrent in all of the films studied is considerably different from what was found for crystalline passive films. The potential dependence of the photocurrent yields Poole-Frenkel behavior. Reverse tunneling processes were also observed at ...

Energy Technology Data Exchange (ETDEWEB)

Managing sites contaminated with munitions constituents is an international challenge. Although the choice of approach and the use of Ecological Risk Assessment (ERA) tools may vary from country to country, the assurance of quality and the direction of ecotoxicological research are universally recognized as shared concerns. Drawing on a multidisciplinary team of contributors, 'Ecotoxicology of Explosives' provides comprehensive and critical reviews available to date on fate, transport, and effects of explosives. The book delineates the state of the science of the ecotoxicology of explosives, past, present, and recently developed. It reviews the accessible fate and ecotoxicological data for energetic materials (EMs) and the methods for their development. The chapters characterize the fate of explosives in the environment, then provide information on their ecological effects in key environmental media, including aquatic, sedimentary, and terrestrial habitats. The book ...

International Nuclear Information System (INIS)

Sealants for radon-resistant foundation construction must seal the gap between concrete sections. Modern sealants have such low permeability that seal performance depends only on the permeability of the material that contacts the sealant. The surface permeability of concrete walls and floors was measured by a specially designed permeameter, which measures the airflow induced by a pressure difference across a temporary test seal applied to the surface. The permeability of bulk concrete is about 10"-"1"5 m"2. Areas free of surface defects had surface permeability ranging from 10"-"1"4 to 10"-"1"6 m"2. However, surface defects are common on concrete wall surfaces, which increase the permeability to >10"-"1"2 m"2, too high for standard seal designs to be adequate as the only method of soil gas and radon exclusion. Radon-resistant seals require either extended contact widths or mechanical removal of the surface layer and defects. (au) (4 refs.).

Energy Technology Data Exchange (ETDEWEB)

The United States and Russia have agreed to jointly develop a solar dynamic (SD) system for flight demonstration on the Russian Mir space station starting in late 1997. Two important components of this SD system are the solar concentrator and heat receiver provided by Russia and the US, respectively. This paper describes optical analysis of the concentrator and solar flux predictions on target receiver surfaces. The optical analysis is performed using the code CIRCE2. These analyses account for finite sun size with limb darkening, concentrator surface slope and position errors, concentrator petal thermal deformation, gaps between petals, and the shading effect of the receiver support struts. The receiver spatial flux distributions are then combined with concentrator shadowing predictions. Geometric shadowing patterns are traced from the concentrator to the target receiver surfaces. These patterns vary with time depending on the chosen Mir flight attitude and ...

DEFF Research Database (Denmark)

Udgivelsesdato: DEC

International Nuclear Information System (INIS)

The purpose of this text is to train engineers and technologists not just to understand corrosion but to control it. Materials selection, coatings, chemical inhibitors, cathodic and anodic protection, and equipment design are covered in separate chapters. High-temperature oxidation is discussed in the final two chapters ne on oxidation theory and one on controlling oxidation by alloying and with coatings. This book treats corrosion and high-temperature oxidation separately. Corrosion is divided into three groups: (1) chemical dissolution including uniform attack, (2) electrochemical corrosion from either metallurgical or environmental cells, and (3) stress-assisted corrosion. Corrosion is logically grouped according to mechanisms rather than arbitrarily separated into different types of corrosion as if they were unrelated. For those university students and industry personnel who approach corrosion ...

Energy Technology Data Exchange (ETDEWEB)

Full text of publication follows: The heat transfer and flow in narrow channels has lots of advantages such as compact structure, high efficiency, design flexibility and so on. So it is widely used in the fields such as the new reactor core plate elements, the once-through stream generator, compact heat exchangers as well as electronic components. In recent years, more strong attentions have been attracted to the thermal-hydraulic characteristics and mechanism of the two-phase flow in narrow channels. As the flow regime characteristics of two-phase flow is fundamental one of them, the research on the two-phase flow regimes and the regime transitions in horizontal rectangular narrow heated channels can provide theoretical foundation and engineering directions to the whole research on the thermal-hydraulic characteristics and mechanism of the two-phase flow in narrow channels. The characteristics of two-phase flow regimes and regime transitions ...

CERN Document Server

A simple analytical model of the barrier discharge in a long gap between opposing plane electrodes is developed. It is shown that the plasma density becomes uniform over large part of the gap in the course of the discharge development, so that one can speak of a formation of a dynamic positive column. The column completely controls the dynamics of the barrier discharge and determines such characteristics as the discharge current, discharge duration, light output, etc. Using the proposed model, all discharge parameters can be easily evaluated

Energy Technology Data Exchange (ETDEWEB)

A dust extraction system removes the contaminated air at source by means of a hood. The extraction system for dust is essentially a ducted air system that prevents excessive employee exposure to dust in the working zone. The four major mechanisms that remove the contaminants in an extraction system are: - capture of contaminants by hoods - transport of contaminated air in duct network - separation of dust in the collector - exhaust of clean air through stack. The current methods of design are based on empirical relations, multi-variable tables, graphs and nomographs that have been derived from the principle of fluid mechanics and particle dynamics. However, the empirical formulae, tables and graphs are used in different geographical locations of the world having different environmental conditions and geo-characteristics of dust particles. Therefore, it is required to establish a rational design method that will be based on ...

British Library Electronic Table of Contents (United Kingdom)

The versatile electrospinning technique was used to successfully align and disperse multiwalled carbon nanotubes (MWCNT) in nylon 6,6 matrix to obtain composite fibers. The morphology of the composite fibers and the dispersion of the CNTs within the fibers were analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. TEM analysis revealed that the CNTs were well-dispersed, separated and aligned along the fiber axis. The thermal and mechanical properties of the composite fibers were characterized as a function of weight fraction of the CNTs. Incorporation of the CNTs in the fibers resulted in an increase in glass-transition temperature (Tg) by 7degreeC, indicating that the addition of CNTs has restricted the mobility of the polymer chains a...

Energy Technology Data Exchange (ETDEWEB)

The conference proceedings contains 30 papers of which five are abstracted separately. The subjects covered include fatigue crack growth in aircraft materials, fractographic measurements, fatigue cracks in nylon 66 blends, cyclic inelastic deformation aspects, prestressing, tensile cracks in creeping solids, creep-crack-growth in 304 stainless steel, high-temperature fatigue, parallel impact loading, numerical fracture dynamic code, J-resistance curves, specimen geometry effects, reactor piping systems, temperature dependence of fracture toughness, small-scale yielding, compact specimens, power hardening materials, semi-empirical fracture analyses, pipeline girth welds, wrought steels, and A36 bridge steels.

DEFF Research Database (Denmark)

We extend the pi-calculus with polyadic synchronisation, a generalisation of the communication mechanism which allows channel names to be composite. We show that this operator embeds nicely in the theory of pi-calculus, we suggest that it permits divergence-free encodings of distributed calculi, and we show that a limited form of polyadic synchronisation can be encoded weakly in pi-calculus. After showing that matching cannot be derived in pi-calculus, we compare the expressivity of polyadic synchronisation, mixed choice and matching. In particular we show that the degree of synchronisation of a language increases its expressive power by means of a separation result in the style of Palamidessi's result for mixed choice.

Energy Technology Data Exchange (ETDEWEB)

A method of assembling two or more parts together that may be metal, ceramic, metal and ceramic parts, or parts that have different CTE. Individual parts are formed and sintered from particles that leave a network of interconnecting porosity in each sintered part. The separate parts are assembled together and then a fill material is infiltrated into the assembled, sintered parts using a method such as capillary action, gravity, and/or pressure. The assembly is then cured to yield a bonded and fully or near-fully dense part that has the desired physical and mechanical properties for the part's intended purpose. Structural strength may be added to the parts by the inclusion of fibrous materials.

International Nuclear Information System (INIS)

An interferometric technique for hard X-rays is presented. It is based on two transmission gratings and a phase-stepping technique, and it provides separate radiographs of the phase and absorption profiles of bulk samples. Tomographic reconstruction yields quantitative three-dimensional maps of the X-ray refractive index and of the attenuation coefficient, with a spatial resolution down to a few microns. The method is mechanically robust, it requires little monochromaticity, and can be scaled up to large fields of view. These are important prerequisites for use with laboratory X-ray sources. Numerous applications ranging from wave front sensing to medical radiography are presently under investigation.

International Nuclear Information System (INIS)

Lithium was selectively extracted from near-neutral aqueous solutions of alkali metal salts. The mechanism by which this was achieved involves the formation of the trioctylphosphine oxide adduct of a lithium chelate of a fluorinated #beta#-diketone, which is then readily extractable into an organic diluent. High separation factors were obtained from sodium, potassium, rubidium, and cesium. The selectivity of the fluorinated #beta#-diketones for lithium over the alkaline earths was found to be poor. A suggested general flowsheet for the recovery of lithium from a salt brine concentrate is included. (author).

Science.gov (United States)

Breakdowns occurring in rf accelerating structures will limit the ultimate performance of future linear colliders such as the Compact Linear Collider (CLIC). Because of the similarity of many aspects of dc and rf breakdown, a dc breakdown study is underway at CERN to better understand the vacuum breakdown mechanism in a simple setup. Measurements of the field enhancement factor ? show that the local breakdown field is constant and depends only on the electrode material. With copper electrodes, the local breakdown field is around 10.8GV/m, independent of the gap distance. The ? value characterizes the electrode surface state, and the next macroscopic breakdown field can be well predicted. In breakdown rate experiments, where a constant field is applied to the electrodes, clusters of consecutive breakdowns alternate with quiet periods. The occurrence and lengths of these clusters and quiet periods depend on the evolution of ?. The application of ...

International Science & Technology Center (ISTC)

Development of a Plant for Neon Isotopes Separation by Low-Temperature Rectification Method

International Nuclear Information System (INIS)

The Median Tectonic Zone (MTZ) of New Zealand is a generally north trending belt of Mesozoic subduction related I-type plutonic, volcanic, and sedimentary rocks in South Island and Stewart Island that separates Permian strata of the Eastern Province Brook Street Terrane from lower to mid Gondwana margin assemblages of the Western Province. High precision isotope dilution U/Pb ages of zircons from 30 rocks are reported. Pre-digestion leaching of zircon in hydrofluoric acid yielded significantly more concordant residues by removing common Pb and dissolving more soluble high-U domains that have been more affected by relatively recent Pb loss. The results show that MTZ magmatism ranges in age from at least Early Triassic to Early Cretaceous (247-131 Ma), with a pronounced gap in the Middle Jurassic. Triassic plutons tend to occur on the eastern side of the MTZ, and they intrude volcanic/sedimentary sequences of the MTZ in Nelson and eastern ...

Energy Technology Data Exchange (ETDEWEB)

The thermomechanical behaviour of clayey soils was examined in a laboratory study because of their importance in some engineering applications such as hydrocarbon extraction from oil-bearing sands and radioactive waste disposal. The slightest temperature variations have been known to have an impact on the mechanical behaviour of clayey soils. In this study, tests were conducted on reconstituted and natural clayey soils using triaxial cells modified to control temperatures. Changes of temperature and stress state were not applied simultaneously. Instead, the tests were divided into two separate sections aimed at studying the thermal and mechanical behaviour of clays. The thermal behaviour tests examined the deformations induced by drainage temperature changes as well as pore-pressure generation and consolidation phenomena. The mechanical behaviour tests, focused on the influence of temperature and ...

International Nuclear Information System (INIS)

Penning trap mass spectrometry is presented as a complementary tool to nuclear spectroscopy experiments for the study of nuclear structure in the vicinity of N=40, Z=28. High-precision mass measurements of the "6"3"-"6"6Fe and "6"4"-"6"7Co isotopes have been carried out with the Low Energy Beam and Ion Trap (LEBIT) Penning trap mass spectrometer. The newly obtained mass values for "6"6Fe and "6"7Co are presented, together with the previously reported LEBIT mass measurements in this region. In the case of "6"5Fe the existence of a new isomer is reported, and an isomer recently discovered by decay spectroscopy in "6"7Co is confirmed. Relative mass uncertainties as low as 4x10"-"8 are obtained. All mass values are found to be in good agreement with previous experimental results with the exception of "6"4Co, where a 5#sigma# deviation is observed. Using these data the two neutron separation energies S_2_n are calculated. However, the large error bars in the mass values ...

Science.gov (United States)

Basic research of the structure and electronic properties of a-Si:H is reported with particular emphasis on the role of defects. The main findings are as follows: (1) low defect density material can be deposited at a high rate using SiH/sub 4/ diluted in He or Ne. Using Ar or Kr results in a high defect density and columnar material; (2) an electrical bias during deposition modifies the band gap, hydrogen concentration and structure; (3) the clustering of hydrogen in the regions between the columns is confirmed; (4) hydrogen diffusion is observed by NMR; (5) the oxidation of an a-Si:H surface results in approx. 3 x 10/sup 11/ cm/sup -2/ dangling bonds at the interface; (6) auger recombination of photoexcited carriers is a significant non-radiative mechanism at low temperatures; (7) non-radiative recombination by diffusion and capture at dangling bonds is observed at temperatures above 50 to 100/sup 0/K; (8) the defect density in doped and ...

Energy Technology Data Exchange (ETDEWEB)

Systematic studies of the NdFeAsOF superconducting energy gap using point-contact Andreev-reflection (PCAR) spectroscopy are presented. At low temperatures the PCAR conductance spectra show a pair of gap-like peaks at about {+-} (4-7) mV and in most cases also a pair of humps at around {+-} 10 mV. Fits to the s-wave two-gap model of the PCAR conductance allowed to determine two superconducting energy gaps in the system. However, the energy-gap features disappear at T* = 15-20 K, much below the particular T{sub c} of the junction under study. At T* a zero-bias conductance (ZBC) peak emerges, which at higher temperatures usually overwhelms the spectrum with an intensity significantly higher than the conductance signal at lower temperatures. Possible causes of this unexpected temperature effect are discussed. In some cases the conductance spectra show just a reduced conductance around ...

International Nuclear Information System (INIS)

Liquid radioactive raffinates from nuclear fuel reprocessing at the Idaho National Engineering and Environmental Laboratory were solidified, or calcines, in a fluidized bed reactor at approximately 500 C to form a dry granular material. This calcine has been provisionally stored near-surface in concrete-encased stainless steel bins at the Idaho Nuclear Technology Engineering Center. Research addressing the permanent immobilization of radioactive waste has been ongoing. One option is to separate the radioactive constituents from the calcine, thereby reducing the radioactive waste volume to be ultimately stored at a national nuclear waste repository. Nitric acid dissolution of the calcine is a key front-end unit operation in the separations option. In order to design calcine dissolution equipment, quantification of dissolution reaction rate parameters is required. A pilot-plant-produced, non-radioactive calcine was utilized to study the ...

Energy Technology Data Exchange (ETDEWEB)

This paper presents a new method for the determination of the energy gap of superconductors. The V/sub max//kT versus ..delta../kT curve was calculated from tunneling theory. The maximum voltage in differential conductance V/sub max/ was measured from the electron tunneling spectrum. From V/sub max//kT and the curve, one can easily calculate the energy gap value ..delta... This method is simple, and the accuracy almost approaches that of the curve-fitting method.

Energy Technology Data Exchange (ETDEWEB)

A new method for determining the energy gap of a superconductor using the maximum in the differential conductance curve of electron tunneling spectrum is given in this paper. The V/sub max//kT versus ..delta../kT curve was calculated from tunneling theory. V/sub max/, the voltage of the conductance maximum, can be measured from electron tunneling spectrum. ..delta../kT can be found from this curve, then the energy gap ..delta.. can be calculated. This method is simple, fast and accurate. The accuracy almost approaches that of the curve fitting method.

Energy Technology Data Exchange (ETDEWEB)

The group- V vacancy pair, the so-called E-center, has recently been demonstrated to have, both in Si and Ge, more complicated energy-level schemes in the energy gap than were previously assumed. The E-center in silicon has, in addition to its well-established single-acceptor level in the upper half of the band gap, also a donor level in the lower half of the band gap; this donor level has lain hidden for more than 40 years. The E-center in Ge has an even more complicated level scheme as it induces, in addition to two levels analogous to those found in Si, also a double-acceptor level in the upper half of the band gap. Thus the E-center in Si can exist in three charge states and the E-center in Ge in four.

Science.gov (United States)

... an Page 15. NSWC TR 86-32 exploding bridgewire detonator containing PETN rather, than a pri'mary explosive. However ...

International Nuclear Information System (INIS)

The disrupted magnetic braking theory for the period gap of cataclysmic variable systems is used to study the binary evolution of low-mass main-sequence-like stars with white dwarf companions. The model is able to reproduce the observed location and width of the gap provided that the average mass transfer rates above the upper edge of the gap are greater than about 1.9 x 10 to the -9th solar masses/yr. For the case of angular momentum loss by magnetic braking, the slope of the mass transfer rate with respect to orbital period is shown to range from 3.4 to 3.7. For the evolutionary sequences considered, the He-3 abundance at the surface of the secondary exceeds 0.0015 after the complete mixing phase, resulting in modifications in the nuclear burning development of nova explosions. 31 refs.

Energy Technology Data Exchange (ETDEWEB)

Energy flows in deep inelastic electron-proton scattering are investigated at a centre-of-mass energy of 296 GeV for the range Q{sup 2}{>=}10 GeV{sup 2} using the ZEUS detector. A comparison is made between events with and without a large rapidity gap between the hadronic system and the proton direction. The energy flows, corrected for detector acceptance and resolution, are shown for these two classes of events in both the HERA laboratory frame and the Breit frame. From the differences in the shapes of these energy flows we conclude that QCD radiation is suppressed in the large-rapidity-gap events compared to the events without a large rapidity gap. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Our Andreev reflection measurements (Phys. Rev. Lett. 87 (2001) 137005) along with other experiments have led to a general consensus that MgB{sub 2} is a multiband superconductor with two main superconducting gaps closing at the same T{sub c}. Here we show the behavior of the small gap as a function of the temperature and magnetic field. This gap is isotropic with T{sub c} of the bulk material but with a specific small (crossover) critical magnetic field of about 1 T much lower than the real H{sub c2}. The latter field is anisotropic and is rather governed by the large gap and strongly anisotropic Fermi surface of the material.

Energy Technology Data Exchange (ETDEWEB)

This report summarizes the major features of the advisory tool `TUNDTEMP`, developed to act as a decision support in the continuous steel casting process. `TUNDTEMP` provides a means to predict abnormal phenomena of temperature origin in the casting that may be difficult to foresee in practical situations. The heart of the system is a semi-empirical calculation model that yields an estimate of the evolution of the tundish temperature of the liquid steel on the basis of a few important casting factors. The user interface of the system is to a large extent based on the visual presentation of the simulated results. The system also contains an optional rule based mechanism that provides assistance in the result interpretation and, if wished, linguistically formulates action recommendations. A separate program has been built for the tuning of the calculation model and for maintenance of the system. At the end of the report, the different tuning ...

CERN Document Server

Theory of quantum games is relatively new to the literature and its applications to various areas of research are being explored. It is a novel interpretation of strategies and decisions in quantum domain. In the earlier work on quantum games considerable attention was given to the resolution of dilemmas present in corresponding classical games. Two separate quantum schemes were presented by Eisert et al. and Marinatto and Weber to resolve dilemmas in Prisoners' Dilemma and Battle of Sexes games respectively. However for the latter scheme it was argued that dilemma was not resolved. We have modified the quantization scheme of Marinatto and Weber to resolve the dilemma. We have developed a generalized quantization scheme for two person non-zero sum games which reduces to the existing schemes under certain conditions. Applications of this generalized quantization scheme to quantum information theory are studied. Measurement being ubiquitous in quantum ...

CERN Document Server

Today, component oriented middlewares are used to design, develop and deploy easily distributed applications, by ensuring the heterogeneity, interoperability, and reuse of the software modules, and the separation between the business code encapsulated in the components and the system code managed by the containers. Several standards answer this definition such as: CCM (CORBA Component Model), EJB (Enterprise Java Beans) and .Net. However these standards offer a limited and fixed number of system services, removing any possibility to add system services or to reconfigure dynamically the middleware. Our works propose mechanisms to add and to adapt dynamically the system services, based on a reconfiguration language which is dynamically adaptable to the need of the reconfiguration, and on a tool of dynamic reconfiguration, a prototype was achieved for the OpenCCM platform, that is an implementation of the CCM specification. This work was partially ...

Energy Technology Data Exchange (ETDEWEB)

Wheeling electric power, the transmission of electricity not owned by an electric utility over its transmission lines, is a term not generally recognized outside the electric utility industry. Investigation of the term`s origin is intriguing. For centuries, wheel has been used to describe an entire machine, not just individual wheels within a machine. Thus we have waterwheel, spinning wheel, potter`s wheel and, for an automobile, wheels. Wheel as a verb connotes transmission or modification of forces and motion in machinery. With the advent of an understanding of electricity, use of the word wheel was extended to be transmission of electric power as well as mechanical power. Today, use of the term wheeling electric power is restricted to utility transmission of power that it doesn`t own. Cogeneration refers to simultaneous production of electric and thermal power from an energy source. This is more efficient than separate production of ...

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.

CERN Document Server

The problem of a spin 1 charged particle with electromagnetic polarizability, obeying a generalized 15-component quantum mechanical equation, is investigated in presence of the external Coulomb potential. With the use of the Wigner's functions techniques, separation of variables in the spherical tetrad basis is done and the 15-component radial system is given. It is shown that there exists a class of quantum states for which the additional characteristics, polarizability, does not manifest itself anyhow; at this the energy spectrum of the system coincides with the known spectrum of the scalar particle. For j=0 states, a 2-order differential equation is derived, it contains an additional potential term 1/r^{4}. In analogous approach wave functions the generalized particle are examined in presence of external Dirac monopole field. It is shown that there exists one special state with minimal conserved quantum number j_{min}. It this solution, ...

Energy Technology Data Exchange (ETDEWEB)

A kinetic model based on the Mars-van Krevelen mechanism that allows to describe the microkinetics of the heterogeneously catalysed partial oxidation of {alpha}, {beta}-unsaturated aldehydes is presented. This conversion is represented by a network, composed of the oxidation of the {alpha}, {beta}-unsaturated aldehyde towards the {alpha}, {beta}-unsaturated carboxylic acid and the consecutive oxidation of the acid as well as the parallel reaction of the aldehyde to products of deeper oxidation. The reaction steps of aldehyde respectively acid oxidation and catalyst reoxidation have been investigated separately in transient experiments. The combination of steady state and transient experiments has led to an improved understanding of the interaction of the catalyst with the aldehyde and the carboxylic acids as well as to a support of the kinetic model assumptions. (orig.)

International Nuclear Information System (INIS)

Heat-transfer augmentation by straight grid spacers in rod bundles is studied for single-phase flow and for post-critical heat flux dispersed flow. The heat transfer effect of swirling grid spacers in single-phase flow is also examined. Governing heat-transfer mechanisms are analyzed, and predictive formulations are established. For single-phase flow, the local heat transfer at a straight spacer and at its upstream or downstream locations are treated separately. The effect of local velocity increasing near swirling spacer is considered. For post critical heat flux (CHF) dispersed flow, the heat transfer by thermal radiation, fin cooling, and vapor convection near the spacer are calculated. The predictions are compared with experimental data with satisfactory agreement.

Energy Technology Data Exchange (ETDEWEB)

The evolution of these new ion-exchange resins hinges upon an understanding of the chemistry of actinide metal complexes as they exist in solution and when interacting with the cationic sites. Molecular modeling of electrostatic interactions between the metal complex and the cationic substrate is used to help visualize uptake mechanisms and, eventually, to predict optimized coordination sites. Thus, these new materials integrate the fields of ion-specific chelation and ion-exchange technology. Synthesized resins contain cationic sites designed to facilitate the uptake of plutonium nitrato complexes from high-nitrate solutions, and they exhibit distribution coefficients that are up to 10 times higher than those observed for commercial resins. Additionally, some new resins show surprisingly large Kd`s for anionic complexes of Am(III) and U(VI).

CERN Document Server

Land snails move via adhesive locomotion. Through muscular contraction and expansion of their foot, they transmit waves of shear stress through a thin layer of mucus onto a solid substrate. Since a free surface cannot support shear stress, adhesive locomotion is not a viable propulsion mechanism for water snails that travel inverted beneath the free surface. Nevertheless, the motion of the freshwater snail, Sorbeoconcha physidae, is reminiscent of that of its terrestrial counterparts, being generated by the undulation of the snail foot that is separated from the free surface by a thin layer of mucus. Here, a lubrication model is used to describe the mucus flow in the limit of small amplitude interfacial deformations. By assuming the shape of the snail foot to be a traveling sine wave and the mucus to be Newtonian, an evolution equation for the interface shape is obtained and the resulting propulsive force on the snail is calculated. This ...

Science.gov (United States)

In this article, we report anticancer activity of 14 anthracenedione derivatives separated from the secondary metabolites of the mangrove endophytic fungi Halorosellinia sp. (No. 1403) and Guignardia sp. (No. 4382). Some of them inhibited potently the growth of KB and KBv200 cells, among which compound 6 displayed strong cytotoxicity with IC(50) values of 3.17 and 3.21 microM to KB and KBv200 cells, respectively. Furthermore, we demonstrate that the mechanism involved in the apoptosis induced by compound 6 is probably related to mitochondrial dysfunction. Additionally, the structure-activity relationships of these compounds are discussed. PMID:20479985

British Library Electronic Table of Contents (United Kingdom)

Electrochemical discharge machining (ECDM) is a promising hybrid process for high-performance machining of non-conductive glass. ECDM drilling has been found to have different characteristics and material removal mechanisms in discharge regime (less than 300??m in depth) and hydrodynamic regime (more than 300??m in depth); however, these regimes are never separately modeled in existing ECDM models, which leads to large prediction error, especially at low applied voltages and high machining depths. Until now, no model is particularly designed for discharge regime, where most material is removed. In this paper, a finite element based model for ECDM drilling in discharge regime is presented. Material removal subjected to a single spark was simulated using finite element method. The drilling d...

Energy Technology Data Exchange (ETDEWEB)

The average American generates four pounds of solid waste per day, yet increasing constraints are being placed on the ability of municipalities to handle waste disposal. Most cities face a scarcity of acceptable landfill sites and conventional incineration and landfill methods have come under strict air, water and soil pollution standards. City administrators are being encouraged to select from a variety of proposed technologies that supplant traditional waste disposal methods, some of which offer the promise of revenues from energy and resource recovery. The problem is to select from available near-term technologies those systems that will fit into a city's long-term solid-waste management program. Broadly, waste-to-energy recovery systems now available to cities may be classified as combustion, pyrolysis, biodegradation, and mechanical front-end systems. It is important to notice that operations used for mechanical front-end systems ...

Energy Technology Data Exchange (ETDEWEB)

The multidimensional countercurrent two-phase flow regimes that occur in a pressurized-water reactor (PWR) vessel downcomer during the refill phase of a large-break loss-of-coolant accident are studied using a transparent 1/10 scale model of a PWR vessel. The various flow regimes and their distribution in the downcomer have been identified and mapped for a range of air-water flooding experiments. The two-phase flow patterns that are identified in the downcomer included various types of film flows, droplet flows, countercurrent churn flows and cocurrent flows depending on the flooding condition. Through observation of the two-phase flow dynamics it was deduced that the physical mechanisms associated with the flooding processes could be separated into a liquid entrainment process and a film flow reversal process. In addition to the above exercise, the effect of non-uniform injection of water into the downcomer via different combinations of cold ...

Science.gov (United States)

The strategies employed by oral streptococci to resist the inimical influences of acidification reflect the diverse and dynamic niches of the human mouth. All of the oral streptococci are capable of rapid degradation of sugar to acidic end-products. As a result, the pH value of their immediate environment can plummet to levels where glycolysis and growth cease. At this point, the approaches for survival in acid separate the organisms. Streptococcus mutans, for example, relies on its F-ATPase, to protect itself from acidification by pumping protons out of the cells. S. salivarius responds by degrading urea to ammonia and S. sanguis produces ammonia by arginolysis. The mechanisms by which these organisms regulate their particular escape route are now being explored experimentally. The picture that emerges is that the acid-adaptive regulatory mechanisms of the oral streptococci differ markedly from those employed by ...

Science.gov (United States)

... Agard Report 272,1960 ... and reattached subsonic turbulent flows obtained downstream ... of flow separations due to deflected control surfaces. ...

British Library Electronic Table of Contents (United Kingdom)

We present a comparative study on the acoustic tunneling through artificial periodical composites, from phononic crystals to acoustic metamaterials. We find that the features of the acoustic tunneling are closely related with the origins of band gaps. In particular, the band gap associated with the negative effective material parameter in the metamaterial results in a better analog of the tunneling effect to the quantum system.

International Nuclear Information System (INIS)

Fluorinated amorphous carbon (a-C:F) films were deposited by radio frequency bias assisted microwave plasma electron cyclotron resonance chemical vapor deposition with tetrafluoromethane (CF_4) and acetylene (C_2H_2) as precursors. The deposition process was performed at two flow ratios R=0.90 and R=0.97, where R=CF_4/(CF_4+C_2H_2). The samples were annealed at 300 deg. C for 30 min. in a N_2 atmosphere. Both Fourier transform infrared and electron spectroscopy for chemical analyzer were used to characterize the a-C:F film chemical bond and fluorine concentration, respectively. A high resolution electron energy loss spectrometer was applied to detect the electronic structure. The higher CF_4 flow ratio (R=0.97) produced more sp"3 linear structure, and it made the a-C:F film smoother and softer. A lifetime of around 0.34 #mu#s and an energy gap of #approx#2.75 eV were observed in both the as-deposited and after annealing conditions. The short carriers lifetime in ...

Energy Technology Data Exchange (ETDEWEB)

The dependence of the photoluminescent properties of In{sub 0.48}(Al{sub {ital y}}Ga{sub 1{minus}{ital y}}){sub 0.52}P alloys (0{le}{ital y}{le}0.5) on growth temperature and substrate misorientation off GaAs(100) has been studied. Samples were grown using low-pressure metalorganic vapor phase epitaxy. By studying the dependence of ordering behavior in InGaP as a function of substrate misorientation and growth temperature simultaneously, a very large range in low-temperature photoluminescence emission energy---135 meV---has been obtained. The photoluminescence linewidth exhibits a strong, continuous dependence on the extent of atomic ordering (the emission energy) in the alloys. The results indicate that inhomogeneity in the microstructure of the material (i.e., between ordered'' domains and the disordered'' matrix) is the dominant photoluminescence broadening mechanism. This investigation has allowed a significant optimization ...

Energy Technology Data Exchange (ETDEWEB)

The structure of hydroxylated oxide films (passive films) formed on Cr(110) in 0.5 M H{sub 2}SO{sub 4} at +0.35, +0.55, and +0.75 V/SHE has been investigated by in situ scanning tunneling microscopy (STM). Cathodic reduction pretreatments at {minus}0.54, {minus}0.64, and {minus}0.74 V/SHE destroy the well-defined topography of the single-crystal electrode and they have been excluded from the passivation procedure. Two different passive film structures have been observed, depending on the potential and time of passivation. At low potential (+0.35 V/SHE), the passive film, consisting mostly of chromium hydroxide, has a noncrystalline and granular structure whose roughness suggests local variations of thickness of ca. {+-} 0.5 nm. A similar structure is observed at higher potential (+0.55 V/SHE), but only for a short polarization time. For longer polarization at 0.55 V/SHE, and at higher potentials (+0.75 V/SHE), a crystalline structure is formed; the higher the potential, the faster the ...

International Nuclear Information System (INIS)

The effect of uniaxial tensile stress on intergranular corrosion (IGC) of AA2024-T3 was studied using the foil penetration technique. Standard ASTM G49 fixed-displacement jigs were modified to allow the use of sheet samples, which were then attached to an electrochemical cell as in the foil penetration setup. The time for IGC to penetrate samples of varying thickness was monitored. This method provides a new approach to bridge the gap between IGC and intergranular stress corrosion cracking (IGSCC). Samples with various orientations relative to the rolling direction were studied in 1.0 M NaCl at controlled anodic potentials. Potentiodynamic polarization measurements indicated that the two breakdown potentials typically observed for AA2024-T3 were lower for stressed samples than for unstressed samples, and the current at a given potential was higher. The penetration rate depended on potential and was higher for stressed samples than for unstressed samples. The ...

Energy Technology Data Exchange (ETDEWEB)

The transfer kinetics of the neutral glycosphingolipid gangliotetraosylceramide (asialo-GM1) were investigated by monitoring tritiated asialo-GM1 movement from donor to acceptor vesicles. Two different methods were employed to separate donor and acceptor vesicles at desired time intervals. In one method, a negative charge was imparted to dipalmitoylphosphatidylcholine donor vesicles by including 10 mol% dipalmitoylphosphatidic acid. Donors were separated from neutral dipalmitoylphosphatidylcholine acceptor vesicles by ion-exchange chromatography. In the other method, small, unilamellar donor vesicles and large, unilamellar acceptor vesicles were coincubated at 45 degrees C and then separated at desired time intervals by molecular sieve chromatography. The majority of asialo-GM1 transfer to acceptor vesicles occurred as a slow first-order process with a half-time of about 24 days assuming that the relative concentration of ...

International Nuclear Information System (INIS)

Bone marrow is one of the most radiosensitive organs. Irradiation causes a marked decrease in the total number of hematopoietic cells in the bone marrow. The reticular meshwork structure of marrow stromal cells, however, is relatively resistant to irradiation. Unimpaired stromal cell structure has been thought to be a prerequisite for the repopulation of hematopoietic cells during recovery from the effects of irradiation. The reticular framework is maintained by cell adhesion apparatuses such as gap junctions. The in vitro radiobiologic survival values of a cloned stromal cell line, H-1/A, were studied (n = 1.8, D0 = 138 cGy). Radiation doses of up to 4000 cGy had no detectable effects on the production of colony-stimulating factor 1. H-1/A cells communicate with each other via gap junctions as determined by the sensitive dye-transfer method. Gap-junctional communication between H-1/A cells was resistant to different levels ...

International Nuclear Information System (INIS)

Photoelectrochemical current response of passive film was investigated for pure Cr and Fe-xCr (x = 8, 14, 18) alloys polarised potentiostatically in 0.1 kmol m"-"3 H_2SO_4 solution. Photoelectrochemical action spectrum could be separated into two or three constituents. These components were considered to be derived from Cr_2O_3 (E_g"o"p"t#propor to#3.6 eV) and Cr(OH)_3 (E_g"o"p"t#propor to#2.5 eV), and possibly CrO OH. The optical band gap, E_g"o"p"t, of each component was almost constant for various applied potentials, polarisation periods, and substrate materials. Flat band potential E_j_b at which the polarity of photocurrent changes from negative to positive with increasing potential was determined for each phase. E_j_b for Cr(OH)_3 on Cr and Fe-Cr alloys was about 250 mV_A_g_/_A_g_C_l. E_j_b for Cr_2O_3 was about 700 mV for Cr and about 500 mV for Fe-Cr alloys. E_j_b of Cr_2O_3 for Fe-Cr alloys slightly shifted in noble direction with ...

Science.gov (United States)

In order to understand not only the mechanisms of earthquakes, but also the origin of diverse behavior of faults and plate boundaries, one must integrate (1) field studies on faults to understand deep intrafault processes, (2) laboratory work to reproduce those processes and determine mechanical and transport properties of fault zones, (3) theoretical and numerical studies analyzing fault motion, including earthquake generation processes, based on the constitutive properties determined by laboratory studies, and (4) seismological and geodetic studies revealing dynamic fault motion during earthquakes and diverse aseismic fault behavior. Ideally, such integrated studies should be carried out for a selected fault that produced an earthquake with good seismic/geodetic records so the prediction from (1) to (3) can be fully tested with (4), rather than selecting favorite data in the literature. Present session is organized to promote such integrated ...

Energy Technology Data Exchange (ETDEWEB)

A process is described for removing carbon dioxide from a feed stream of natural gas, having at least methane, ethane and heavier hydrocarbon, comprising: separating the feed stream in a first separator to form a first stream, having substantially all of the propane and heavier hydrocarbons and carbon dioxide and ethane, and a second stream, having methane, carbon dioxide and ethane; mixing the second stream with a polar compound to form a third stream; separating the vapor and liquid of the third stream in the bottom portion of an absorber; absorbing carbon dioxide and ethane from the separated vapor of Step C in a lean portion of the polar compound in the absorber, the absorber carbon dioxide and ethane forming a fourth stream; separating the ethane from the polar compound and carbon dioxide in a separator; separating the first stream in a ...

International Nuclear Information System (INIS)

The newly discovered oxypnictide family of superconductors show very high critical temperatures of up to 55 K. Whilst there is growing evidence that suggests a nodal order parameter, point contact Andreev reflection spectroscopy can provide crucial information such as the gap value and possibly the number of energy gaps involved. For the oxygen deficient NdFeAsO_0_._8_5 with a T_c of 45.5 K, we show that there is clearly a gap value at 4.2 K that is of the order of 7 meV, consistent with previous studies on oxypnictides with lower T_c. In addition, taking the spectra as a function of gold tip contact pressure reveals important changes in the spectra which may be indicative of more complex physics underlying this structure. (rapid communication)

British Library Electronic Table of Contents (United Kingdom)

This paper presents a new method of extracting biologic particles from a mixture of particles. The method is based on the pumping effect in a p-shaped ultrasonic actuator, which has a gap between its two vibrating metal plates. An adhesive tape is placed at a proper position in the gap. Due to the pumping effect which is induced by the sound field in the gap, the particles with smaller mass and radius in the mixture can be pumped up to reach the adhesive tape; while the ones with larger mass cannot. Therefore, the particles with smaller mass and radius can be extracted from the mixture. A theoretical model which can well explain the operation principle and experimental phenomena is developed. By the experimental results and the theoretical analyses based on the model, the validity of the m...

British Library Electronic Table of Contents (United Kingdom)

The design and operating principle of a small (50 mm in diameter and 100 mm in height) ???-73C vacuum spark gap are described. It is shown that it can be efficiently switched using a control circuit with a low (?900 V) supply voltage, which is based on an inductive energy storage and a diode opening switch that forms a high-voltage igniting pulse with a rise time of nanosecond duration. The ???-73C switching process is investigated at different rise times of igniting voltage pulses and different igniting current amplitudes. The results of tests of the spark gap operating in regimes of switching current pulses with an amplitude of 12 kA and a rise time of 800 ns are presented.

Science.gov (United States)

A separation phenomenon occurring during the Charpy impact test of API X80 pipeline steels was investigated in the present study. A detailed microstructural analysis of fractured impact specimens showed that the band structure of bainite elongated along the rolling direction worked as prior initiation sites for separations, and that the number and length of the separations increased with the increasing volume fraction of bainite. In the steels having high work hardenability, tearing-shaped separations were found because the hammer-impacted region was seriously hardened during the impact test, which led to the reduction in the impact toughness. As the test temperature decreased, the tendency toward separations increased, but separations were not found when the cleavage fracture prevailed at very low temperatures. These findings suggested that the formation of ...

Energy Technology Data Exchange (ETDEWEB)

Measurements of temperature and NO concentration in laminar, partially premixed methane-air flames stabilized on a ceramic burner in coflow are reported. The NO concentration and temperature were determined by laser-induced fluorescence (LIF) and coherent anti-Stokes Raman scattering (CARS), respectively. Upstream heat loss to the burner was varied by changing the exit velocity of the fuel-air mixture at a constant equivalence ratio of 1,3; this alters the structure of the flame from an axisymmetric Bunsen-type to a strongly stabilized flat flame. To facilitate analysis of the results, a method is derived for separating the effects of dilution from those of chemical reaction based on the relation between the measured temperature and the local mixture fraction, including the effects of upstream heat loss. Using this method, the amount of NO formed during burnout of the hot, fuel-rich combustion products can be ascertained. In the Bunsen-type flame, it is seen that ...

Science.gov (United States)

Beta silicon carbide is an excellent candidate semiconductor material for demanding applications in high power and high temperature electronic devices due to its high breakdown voltage, relatively large band gap, high thermal conductivity and high melting...

International Nuclear Information System (INIS)

We compare experimental data for temperature dependence of the magnetic order parameter and the magnetic excitations (spin waves) in materials with a quenched orbital moment and a well-defined spin quantum number. It is observed that the thermal decrease of the two quantities proceeds according to the same analytical function of the type y(T)=1-cT"#epsilon# with an identical exponent #epsilon#. This power function applies not only asymptotically for T->0 but holds over a wide temperature range. The exponent #epsilon# is universal, i.e. independent of spin order type and lattice symmetry and depends only on the dimensionality of the relevant interactions and on whether the spin quantum number is integer or half-integer. The different T"#epsilon# functions are identified as representations of stable universality classes. The fact that order parameter and magnetic excitations follow the same T"#epsilon# function shows that the two quantities belong to the same universality class. The ...

Science.gov (United States)

The object of the test was to develop a method to field test the Exploding Bridgewire (EBW) System for proper functioning prior to use. Two basic designs were conceived and tested. The first design using a two element spark gap and a calibrated fuse link ...

UK PubMed Central (United Kingdom)

CF-23“The biggest stumbling block for biological sciences turned out to be synthetic organic chemistry” – Elias A. Zerhouni, Former NIH Director in Chemical...Full Text Available

Science.gov (United States)

In this paper, necessary and sufficient conditions for successful detection of errors in a binary adder by any separate code are developed. The author demonstrates the existence of separate checking codes for addition modulo (2 sup n) ( n > or = 4) and mo...

Science.gov (United States)

Children Who Won't Go To School (Separation Anxiety) No. 7; Updated March 2011 Click here to ... and behaviors are common among children with separation anxiety disorder. The potential long-term effects (anxiety and ...

Energy Technology Data Exchange (ETDEWEB)

This paper represents a parametric study of the amplification factor to account for rebound effects in the Energy Balance Method. Of the 66 distinct cases we chose for our parametric study, the amplification factor of 1.1 seems sufficient except in four borderline cases where the carbon steel pipes are small or have very small gaps between the pipes and the pipe whip restraints. We conclude that the amplification factor generally decreases as the parameters gap size, hinge-to-break distance and overhang increase.

International Nuclear Information System (INIS)

Experiments are described on a plasma cathode with biased grids to prevent entry of ions into the electron extraction gap. The cathode has potential applications to the generation of high-current pulsed electron beams. Operation at 20 A/cm"2 is theoretically possible. The source combines the low average power consumption of a plasma cathode with many of the attractive features of thermionic cathodes, such as space-charge-limited extractor gap electron flow, fast turn-on, and no diode closure. Initial experiments are reported at the 2 A/cm"2 level for pulse lengths to 160 #mu#s.

International Nuclear Information System (INIS)

The Gamma Physics (GaP) program of physical phenomena investigation is proposed on #gamma#p, #gamma#e and #gamma##gamma# colliders at TeV energies. The program contains specialized software (CompHEP system) created for automation of particle interaction processes calculations in the framework of various gauge models. Preliminary physical results are presented (heavy quark production, W, Z production, supersymmetry etc.), and further software development is suggested. (R.P.) 22 refs., 8 figs., 4 tabs.

International Nuclear Information System (INIS)

Hitherto in this laboratory, ionization coefficients alpha and attachment coefficients #eta# have been determined from Townsend's discharge experiments by a curve-fitting method. However, the method proved to be laborious, Formulae have been derived in this paper to give value of alpha and #eta# as a function of Isubo, Isub1 and Isub2 where Isubo is the photoelectric current at a gap setting d and Isub2 the current at another gap setting 2 d. The values of alpha and #eta# obtained give currents in agreement to within 3% in the best cases with the observed currents.

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The dispersion curves E(k-bar) have been calculated for bound and resonant (110) surface states of AlSb, AlAs, and AlP. AlSb is predicted to have no surface states within the bulk fundamental band gap, but AlAs and AlP are predicted to have surface state band minima which are very near the conduction band edge, and could lie either within the gap or immediately above the edge.

International Nuclear Information System (INIS)

A graphic approach, terms a Genetic Activity Profile (GAP), was developed to display a matrix of data on the genetic and related effects of selected chemical agents. The profiles provide a visual overview of the quantitative (doses) and qualitative (test results) data for each chemical. Either the lowest effective dose or highest ineffective dose is recorded for each agent and bioassay. Up to 200 different test systems are represented across the GAP. Bioassay systems are organized according to the phylogeny of the test organisms and the end points of genetic activity. The methodology for producing and evaluating genetic activity profile was developed in collaboration with the International Agency for Research on Cancer (IARC). Data on individual chemicals were compiles by IARC and by the US Environmental Protection Agency (EPA). Data are available on 343 compounds selected from volumes 1-53 of the IARC Monographs and on 115 compounds identified ...

Energy Technology Data Exchange (ETDEWEB)

Counter-current two-phase flows of air-water in narrow rectangular channels with offset-strip fins have been experimentally investigated in a 760 mm long and 100 mm wide test section with 3.0 and 5.0 mm gap widths. The two-phase flow regime, channel-average void fractions and two-phase pressure gradients were studied. Flow regime transition occurred at lower superficial velocities of air than in the channels without fins. In the bubbly and slug flow regimes, elongated bubbles rose along the subchannel formed by fins without lateral movement. The critical void fraction for the bubbly-to-slug transition was about 0.14 for the 3 mm gap channel and 0.2 for the 5 mm gap channel, respectively. Channel-average void fractions in the channels with fins were almost the same as those in the channels without fins. Void fractions increased as the gap width increased, especially at high superficial velocity of air. ...

Science.gov (United States)

... In: Separated Flows, AGARD CP No. ... on thin wings in two-dimensional incompressible flow. ... fields in the region of separating and reattaching flows. ...

Science.gov (United States)

Surface pressure measurements at mid span indicate that flow separation begins near ..... Turbomachinery Flows, AGARD Propulsion Energetics Panel, 1998. ...

Science.gov (United States)

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

Energy Technology Data Exchange (ETDEWEB)

Vanadium alloys exhibit important advantages as a candidate structural material for fusion first wall/blanket applications. These advantages include fabricability, favorable safety and environmental features, high temperature and high wall load capability, and long lifetime under irradiation. Vanadium alloys with (3-5)% chromium and (3-5)% titanium appear to offer the best combination of properties for first wall/blanket applications. A V-4Cr-4Ti alloy is recommended as the reference composition for the ITER application. This report provides a summary of the R&D conducted during 1994 in support of the ITER Engineering Design Activity. Progress is reported for Vanadium Alloy Production, Welding, Physical Properties, Baseline Mechanical Properties, Corrosion/Compatibility, Neutron Irradiation Effects, Helium Transmutation Effects on Irradiated Alloys, and the Status of Irradiation Experiments. Separate abstracts have been prepared for ...

International Nuclear Information System (INIS)

There are two major distinct activities involved with reprocessing of nuclear fuel. They are: a) Mechanical handling of the fuel in the head end plants; and b) chemical dissolution and separation of unused fuel, useful by-products and waste products. Plants and facilities associated with the former include significant remote handling equipment that is designed for handling of fuel for normal production processes. These equipment are selected and designed to meet the design throughput of the plant taking into consideration ease of their operation and maintenance in conjunction with statutory regulations on safety and operator dose uptake. Nevertheless, during the life of the plant, there are instances when special equipment is called for to access part of the plant and undertake tasks such as inspection, maintenance and modification to improve the existing process. BNFL has much experience in the design and application of remote handling ...

International Nuclear Information System (INIS)

The atomic explosions in Hiroshima and Nagasaki made the name radiation itself become a nightmare. Notwithstanding this, radiation continued to serve the mankind specially in diagnosis of several human diseases and in the treatment of intractable malignancies. With their latest research tools biologists have now shown a significant shift in the earlier paradigm; even the concept that radiation initiates cancer appears to be no longer tenable. On the contrary, selective radiation doses inhibit growth of cancer cells and radiation in combination with many chemotherapeutic drugs, radiosensitizing chemicals and/or hyperthermia, is emerging as a new modality for cancer treatment which offers high therapeutic advantages. In addition, the deleterious effects of radiation can now be strategically counter poised by the use of many drugs and chemicals. This has been possible by the newer insights gained in the mechanism of biological effects of radiation. The fate of ...

Energy Technology Data Exchange (ETDEWEB)

We study double Higgs boson production at future linear colliders while paying special attention to the option of high-energy and high-luminosity photon beams. The main purpose is to examine the feasibility of {ital e}{sup +}{ital e}{sup {minus}}, {gamma}{ital e}, and {gamma}{gamma} colliders in order to establish bounds on the value of triple Higgs coupling, which could be crucial for understanding a spontaneous breaking mechanism. We consider mainly those cases of light and intermediate Higgs bosons, including an analysis of the electroweak backgrounds. The mass range {ital M}{sub {ital H}}{approximately}{ital M}{sub {ital Z}} is discussed separately. It is shown that for a light Higgs boson the {ital H}{sup 3} coupling can be visible, even at a future linear {ital e}{sup +}{ital e}{sup {minus}} collider at 500 GeV. For an intermediate Higgs boson, a collider with TeV energies is suitable for investigations. We estimate the bounds on the ...

Energy Technology Data Exchange (ETDEWEB)

This proceedings is the compilation of papers presented at the ninth PV Performance and Reliability Workshop held at the Sheraton Denver West Hotel on September 4--6, 1996. This years workshop included presentations from 25 speakers and had over 100 attendees. All of the presentations that were given are included in this proceedings. Topics of the papers included: defining service lifetime and developing models for PV module lifetime; examining and determining failure and degradation mechanisms in PV modules; combining IEEE/IEC/UL testing procedures; AC module performance and reliability testing; inverter reliability/qualification testing; standardization of utility interconnect requirements for PV systems; need activities to separate variables by testing individual components of PV systems (e.g. cells, modules, batteries, inverters,charge controllers) for individual reliability and then test them in actual system configurations; more results ...

International Nuclear Information System (INIS)

The microstructural development and grain-coarsening behavior of WC-Co alloys, with and without a VC additive, were investigated. The primary goal was to determine the mechanism through which VC acts as a grain-growth inhibitor. The study involved long-time sintering experiments (1 to 100 hours) on fully dense material, nascent stage sintering (90 to 1,320 seconds) starting with the green compact, and surrogate liquid phase experiments to characterize the WC powder prior to sintering. Quantitative microstructural analysis using intercept length distributions was performed for the long-term sintering. The nascent stage experiments involved the measurement of the specific surface area (S_v) of each type of interface separately allowing the determination of the contribution of each developing entity to the overall microstructural evolution. The VC addition has been found to enhance the breakup of multigrained particles in the earliest stages of ...

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The Electromagnetic Fluctuations (EMF) diagnostic will be used to monitor ion fluctuations which could be unstable in MFTF-B. Each probe assembly includes a high impedance electrostatic probe to measure potential fluctuations, and a group of nested, single turn loops to measure magnetic fluctuations in three directions. Eventually, more probes and loops will be added to each probe assembly for making more detailed measurements. The sensors must lie physically close to the plasma edge and are radially positionable. Also, probes at separate axial locations can be positioned to connect along the same magnetic field line. These probes are similar in concept to the rf probes used on TMX, but the high thermal load for 30-second shots on MFTF-B requires a water-cooled design along with temperature monitors. Each signal channel has a bandwidth of .001 to 150 MHz and is monitored by up to four different data channels which obtain amplitude and frequency information. This ...

Science.gov (United States)

Recent investigations of wood plastic composites have revealed a detrimental effect of using lubricant systems in production. This includes nullifying part or all of the mechanical benefit of using a polar compatibilizer, maleic anhydride polypropylene (MAPP), in the composite formulation. This investigation utilizes lubricants labeled with deuterium in conjunction with Fourier transform infrared (FT-IR) spectroscopy to allow for the separation of individual lubricants from all other material constituents. All of the deuterium labeled lubricants, used without MAPP, revealed their expulsion from the wood interface during crystallization. MAPP coupling agent was found to exist near the wood, but it is unclear if any covalent bonding with the hydroxyl functionality on the wood surface occurred. The addition of zinc stearate lubricants appears to nullify the activity of the anhydride functionality near the wood surface as evidenced by a shift in ...

International Nuclear Information System (INIS)

INSAG has emphasized that safety culture has two general components: the organizational framework and the attitude of the staff. To develop a structured approach to the assessment of safety culture, we propose that the highly formalized nature of nuclear power plant organizations be exploited. The prime coordinating mechanism of NPP organizations is the standardization of work processes, where a work process is defined as a standardized sequence of tasks designed to achieve a specific goal (an example is the maintenance work process). The predictable nature of work processes is exploited by the Work Process Analysis Model (WPAM) to conduct a systematic analysis that identifies the desirable characteristics of work processes and develops performance measures for their strengths and weaknesses. These can provide a set of tangible characteristics of a good safety culture. It is argued in this paper that the analysis of normal power production and investment protection ...

Energy Technology Data Exchange (ETDEWEB)

As characterization of artificial cracks formed underground by using the water pressure fracturing method, experiments have been carried out to detect relationship of pressurization and S-wave propagation time with the polarizing direction dependence. Openings are created when pressure in the vicinity of the artificial cracks increases greater than reopening pressure of micro cracks. Elastic wave velocity decreases in this region because of water in the opened micro cracks. Anisotropy is created in the S-wave propagation velocity due to influence from anisotropic reopening region when the artificial cracks are pressurized, and is separated into two components which polarize orthogonally with each other (micro splitting). Field experiments conducted at the Higashi-hachimantai field were analyzed by using wavelet transform. It was possible to detect the S-wave arrival time at high accuracy, and the arrival of an orthogonally polarized wave was observed in 0.03 to ...

International Nuclear Information System (INIS)

Thermodynamic consideration and process calculations at equilibrium conditions showed that processes for separating gas mixtures by partial condensation at low temperatures using turboexpanders have got less energy losses than processes with quasi isobar partial condensation. Compared to the low-pressure parts of condensing steam turbines in turboexpanders less erosion problems are to expected for such separating processes. Separation of liquid in the machine, however, is more difficult withouf additional measures. (orig.).

KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

Separate abstracts were prepared for individual papers. (MHR)

Energy Technology Data Exchange (ETDEWEB)

Short communication.

Energy Technology Data Exchange (ETDEWEB)

A radiochemical method of separation of {sup 203}Hg from {sup 181}Hf is described. The method involves separation by Dowex 50W- X 8, 100-200 mesh, cation exchange resin using 1 M hydrochloric acid as the eluant. The chemical yield for the separation of mercury is > 85% and the decontamination factor is >10{sup 4}. The {sup 181}Hf can be eluted from the column by 4 M HCl.

International Nuclear Information System (INIS)

Nuclear forensic science has become increasingly important for global nuclear security. However, many current laboratory analysis techniques are based on methods developed without the imperative for timely analysis that underlies the post-detonation forensics mission requirements. Current analysis of actinides, fission products, and fuel-specific materials requires time-consuming chemical separation coupled with nuclear counting or mass spectrometry. High-temperature gas-phase separations have been used in the past for the rapid separation of newly created elements/isotopes and as a basis for chemical classification of that element. We are assessing the utility of this method for rapid separation in the gas-phase to accelerate the separations of radioisotopes germane to post-detonation nuclear forensic investigations. The existing state of the art for thermo chromatographic ...

International Nuclear Information System (INIS)

The beta transformation characteristics and mechanical properties of the #beta# titanium alloy Ti_5_0Zr_3_0Nb_1_0Ta_1_0 in the temperature range between 200 and 900 deg. C have been studied by means of X-ray diffraction (XRD), Vickers hardness (HV), and tensile test techniques. In the as-rolled state, only #beta#-phase was identified by XRD. Upon heat-treating at 250 deg. C for 4 h, the #alpha#-phase was precipitated from the #beta#-phase matrix, and leading to an increase of Vickers hardness. A maximum HV value was observed at 400 deg. C, and then HV value decreased with increasing heat-treating temperature. Above 650 deg. C, HV value remained almost constant. During heat-treating at 300-650 deg. C, the decomposition of the metastable #beta#-phase has been found to proceed through a phase separation reaction leading to the formation of #beta#-Ti and #beta#-Zr b.c.c. solid solution phases rather than the formation of solute rich and solute lean ...

Energy Technology Data Exchange (ETDEWEB)

The heat transfer augmentation effect by the unsteady heat conduction between the particles and heat transfer surface is one of the main factors, causing the heat transfer augmentation around the stagnation point in the gas-solid two-phase impinging jet flow. By separating and evaluating that effect, material influence on it was studied of particles and heat transfer surface, together with change by the jet flow condition. That effect enlarged with enlarging in heat capacity, multiplied by the heat conduction coefficient, of both the particles and heat transfer surface, and if both of them were constant in material combination, was dominated by the contact frequency of particles per unit time. Therefore in case of lading solid particles, equal in weight, that effect enlarges with diminishing in particle diameter. Such a heat transfer augmentation mechanism model is universally applicable to the data by Yoshida et al., using comparatively large ...

Energy Technology Data Exchange (ETDEWEB)

The mechanism of cobalt uptake was investigated using cells of the giant alga Chara corallina in which it is possible to resolve separately uptake by the cell wall and actual influx across the cell membrane. The absorption of {sup 60}Co by Chara cells appeared to saturate within 2 h. but this was mainly due to rapid uptake into the cell wall which accounted for 87-92% of the total activity. Even after prolonged desorption most of the cell-associated {sup 60}Co was found on the cell wall. The intracellular distribution of absorbed {sup 60}Co was investigated by fractionating the cell into cytoplasm and vacuole. It was shown that {sup 60}Co influx to the vacuole occurs simultaneously with influx to the cytoplasm. The transported species appears to be Co{sup 2+} rather than the less charged Co(OH){sup +} or Co(O){sub 2}. {sup 60}Co influx is pH dependent (optimum pH 7-9), and is sensitive to some other divalent metals. Influx from solutions ...

Energy Technology Data Exchange (ETDEWEB)

The reactions of CF{sub 3}O radicals with (1) NO and (2) NO{sub 2} were studied using two different experimental techniques. A laser photolysis/LIF detection method was applied for measuring the rate constants as a function of temperature (T=222-302 K) and total pressure (p{sub tot}=7-107 mbar). Whereas the reaction with (1) NO was found to be independent of temperature and pressure with k{sub 1}=(4.5{+-}1.2) x 10{sup -11} cm{sup 3}s{sup -1}, the reaction with (2) NO{sub 2} was found to be dependent on both of these variables. The temperature dependence of k{sub 2} in the high pressure limit can be given by the expression k{sub 2{infinity}}{sup -}(T)=(8{+-}5) x 10{sup -13} exp ((863{+-}194) K/T) cm{sup 3}s{sup -1}. The product distributions of the two reactions were determined in separate experiments using steady-state photolysis combined with FTIR spectroscopy. For reaction (1) only CF{sub 2}O was found as a reaction product with a yield of 0.93{+-}0.10, ...

International Nuclear Information System (INIS)

Hydrolyzates of tissues that had been labeled with [14C]proline often contain significant amounts of cis-4-hydroxy[14C]proline. Since animal cells do not contain an enzyme which can effect formation of cis-4-hydroxyproline, there are only two possible explanations for its presence. Either it is formed during acid hydrolysis of trans-4-hydroxyproline (which is synthesized by cells and is a common constituent of connective tissues), or it is produced by a nonenzymatic mechanism such as attack by oxygen radicals. It is important to resolve this issue because if a nonenzymatic mechanism is active in connective tissues, then it will be necessary to reevaluate currently accepted ideas about production of hydroxyproline. This communication describes a method for distinguishing between the two alternate explanations. Tissues or cells are labeled with [14C]proline, and then a known amount of trans-4-hydroxy[3H]proline is added to each sample before ...

International Science & Technology Center (ISTC)

Investigation of Destruction Mechanisms in Reactor Steels and Alloys under Cycling Deformation

International Nuclear Information System (INIS)

In laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS), the properties of laser-generated aerosols, such as size and composition, are crucial for matrix-independent quantification. In this study, the aerosol particle morphology and elemental composition generated by two state-of-the-art laser systems (ArF excimer nanosecond-UV laser and Ti:sapphire femtosecond-IR laser) were investigated by electron microscopic techniques. Electrostatic sampling of the aerosols directly onto transmission electron microscopy (TEM) grids allowed us to study the morphology and elemental composition of the aerosols using TEM and TEM-EDX (energy dispersive X-ray spectroscopy) analyses, respectively. The results of the electron microscopic studies were finally compared to the LA-ICPMS signals of the main matrix components. The investigations were carried out for non-conducting materials (glass and zircon), metallic samples (steel and brass) and semiconductors (sulfides). The studies ...

Energy Technology Data Exchange (ETDEWEB)

The influence of small amounts of alloying elements (0.36% Cu and 0.47% Cr) on the semiconducting properties of passive films formed on weathering steels was investigated either in tetraborate/boric acid buffer solution (pH 9.2) or artificial atmospheric environment (SO{sub 2}-containing environment). The electrochemical behaviour was assessed by potentiodynamic polarisation, capacitance measurements and photoelectrochemistry. The chemical characterisation of the films was carried by Auger electron spectroscopy. The polarization results obtained in the buffer solution show that the addition of chromium decreases the passive current density. The capacitance results show that the films behave as an n-type semiconductor with shallow and deep donor levels situated in the forbidden gap. The presence of copper seems to affect the density of the shallow and of the deep donor levels in the forbidden gap, and as chromium, it also decreases the doping ...

International Nuclear Information System (INIS)

We studied the influence of alloying on the structural and electronic properties of the unrelaxed and relaxed Si_1_-_yC_y random alloys by means of ab initio theoretical calculations using two methods: (i) a supercell approach in connection with the plane-wave pseudopotential method; (ii) the full-potential augmented plane-wave plus local orbitals (APW+lo) method. The first method is used to obtain the relaxed atomic structure. The relaxed atomic positions obtained by pseudopotential calculations were used to calculate the band structure via the second method. The local density approximation was used for the exchange and correlation energy density functional. We investigated the lattice parameters and band gap energies. We found that a quite smaller gap appears in the neighborhood of y=0.03125 concentration of C atoms. The band gap shows a large anomalous bowing and is strongly composition dependent. The electron densities ...

International Nuclear Information System (INIS)

The credibility of the model proposed by Ghosh in predicting the refractive indices of mixed semiconductor crystals of technological importance within their miscibility range as a function of band gap is demonstrated. The high-frequency refractive indices of four quaternary alloys Al_xGa_1_-_x_-_yIn_yP (y = 0.49, 0 #<=# x #<=# 0.51), InSb_xAs_1_-_x_-_yP_y (y = 2.2x, 0 #<=# x #<=# 0.313, 0 #<=# y #<=# 0.638), Cd_xZn_1_-_x_-_yHg_ySe (x + y = 1, 0.153 #<=# x #<=# 0.684, 0.316 #<=# y #<=# 0.847), and CdS_1_-_x_-_ySe_xTe_y (x + y = 1, 0.15 #<=# x #<=# 0.93, 0.07 #<=# y #<=# 0.85) are calculated according to the relation n"2-1 = A/(E_g + B)"2 where A is an energy gap dependent constant and B is a constant depending on crystal ionicity. The calculated values show excellent agreement with the experimental data thus justifying the validity of the model.

Energy Technology Data Exchange (ETDEWEB)

The integrity of the RPV head and reactor internals was assessed by means of fluid-structural analyses using a coupled method to evaluate the water hammer phenomenon arising from high burnup fuel failure under RIA conditions. The fluid viscosity effect on the water column burst as well as the complex three-dimensional flow paths caused by a core shroud and standpipes were considered in this study. The three analysis scenarios were designed to investigate the above mentioned influential factors separately. In the first scenario, a two-dimensional axisymmetric reactor vessel model without any reactor internals was modeled to assess the influence of the fluid dynamics in the NSC RIA regulatory evaluation. This model has an actual RPV geometry and can be simply separated from other influential factors in order to concentrate only on investigation of the fluid viscosity effect. In the second scenario, a two-dimensional axisymmetric reactor vessel ...

International Nuclear Information System (INIS)

The Bragg-curve detector of the parallel plate ionization chamber type generates a signal that is a distorted replica of the original Bragg-curve. In result of this distortion, the signal peak height is not only a function of the atomic number of the heavy ion, as it is often stated, but also of the particle mass. This mass effect was studied with the aid of computer simulation, and it was found to be dependent on the Frisch grid to anode gap width and on the detector gas. The charge resolution of the detector is affected very significantly by this mass dependence of the signal peak height. Therefore, a careful selection of the detector gas and the grid to anode gap width is necessary, if good charge resolution over a wide range of heavy ions is required. (orig.).

British Library Electronic Table of Contents (United Kingdom)

Purpose - The service-dominant (S-D) logic views supply chains as value co-creation networks. These networks promote knowledge growth amongst network members via resource deployment and coordination. The exchange of knowledge and utilization of operant resources among the network members leads to co-created service offerings and value proposals for the end-users, with the ultimate goal of transforming end-user experiences to perceptions of superior value-in-use. The purpose of this paper is to develop an illustration of the value co-creation concept and use this illustration as guide to examine the research gaps that are yet to be tapped in the area where supply chain networks and S-D logic intersects. Design/methodology/approach - The literature on S-D logic is reviewed and research gaps ...

Energy Technology Data Exchange (ETDEWEB)

The pressure dependence of the photoluminescence (PL) transition associated with the fundamental band gap of ZnO nanowires has been studied at pressures up to 15 GPa. ZnO nanowires are found to have a higher structural phase transition pressure around 12 GPa as compared to 9.0 GPa for bulk ZnO. The pressure-induced energy shift of the near band-edge luminescence emission yields a linear pressure coefficient of 29.6 meV/GPa with a small sublinear term of -0.43 meV/GPa{sup 2}. An effective hydrostatic deformation potential -3.97 eV for the direct band gap of the ZnO nanowires is derived from the result.

Energy Technology Data Exchange (ETDEWEB)

The Bragg-curve detector of the parallel plate ionization chamber type generates a signal that is a distorted replica of the original Bragg-curve. In result of this distortion, the signal peak height is not only a function of the atomic number of the heavy ion, as it is often stated, but also of the particle mass. This mass effect was studied with the aid of computer simulation, and it was found to be dependent on the Frisch grid to anode gap width and on the detector gas. The charge resolution of the detector is affected very significantly by this mass dependence of the signal peak height. Therefore, a careful selection of the detector gas and the grid to anode gap width is necessary, if good charge resolution over a wide range of heavy ions is required.

Energy Technology Data Exchange (ETDEWEB)

The IEA has identified energy efficiency as essential to achieving a sustainable energy future. In order to improve energy efficiency in industry one of the priority areas for further action is the promotion of more and higher quality energy management (EM) activity. However, there are significant gaps in the current implementation of EM. One method of bridging these gaps would be the creation of an EM Action NetworK (EMAK) to bring practical support to energy managers, connect energy managers to energy policy makers, and interconnect these networks globally. The paper describes possible aims, activities, scope, structure, timelines and approaches related to EMAK and looks at specific tasks that would be important in the set-up and implementation.

International Nuclear Information System (INIS)

The electronic structures of platinum group elements (Ru, Os, Rh, Ir, Pd, and Pt) silicides have been calculated. Ir_3Si_5 is a semiconductor with the direct gap of 1.14 eV. Among monosilicides, RuSi and OsSi with the FeSi-type structure are semiconductors with the gap values of 0.21 and 0.41 eV but RhSi, IrSi, PdSi, and PtSi with the MnP-type structure are metals. No semiconducting compounds can be found in other platinum group elements silicides other than known Ru_2Si_3, Os_2Si_3, and OsSi_2.

Energy Technology Data Exchange (ETDEWEB)

Spectroscopy based on the Andreev reflection (AR) process at the interface between the normal metal tip and the superconductor has become one of the very successful methods for studies in novel exotic superconductors. The method is capable to address the size, symmetry as well as multiplicity of the superconducting order parameter. The method provided one of the first evidences of the two-gap superconductivity in MgB{sub 2} with a detailed temperature dependence of the both gaps. A theory treating the Andreev reflection spectroscopy in the mixed state is missing. We analyse the AR spectra of MgB{sub 2} in the mixed state via modelling the magnetic pair-breaking by the increasing spectral broadening parameter {gamma}. As a result a non-trivial pair breaking effect in the {pi}-band is found.

CERN Document Server

The work identifies the first lattice decoding solution that achieves, in the general outage-limited MIMO setting and in the high-rate and high-SNR limit, both a vanishing gap to the error-performance of the (DMT optimal) exact solution of preprocessed lattice decoding, as well as a computational complexity that is subexponential in the number of codeword bits. The proposed solution employs lattice reduction (LR)-aided regularized (lattice) sphere decoding and proper timeout policies. These performance and complexity guarantees hold for most MIMO scenarios, all reasonable fading statistics, all channel dimensions and all full-rate lattice codes. In sharp contrast to the above manageable complexity, the complexity of other standard preprocessed lattice decoding solutions is shown here to be extremely high. Specifically the work is first to quantify the complexity of these lattice (sphere) decoding solutions and to prove the surprising result that the complexity ...

International Nuclear Information System (INIS)

This paper reports that only a few years ago superconducting magnetic separation was viewed as the next major market for superconducting magnets. The first commercial units had been installed, worked flawlessly, and demonstrated real economic viability. The potential market was seen as quite large, and many people believed that superconducting magnetic separation would soon show the same rapid growth that MRI had demonstrated after its initial success. These hopes even prompted IGC, one of the top MRI magnet builders, to form a separate division devoted to magnetic separation. Despite the existence of Magstream, IGC has not been overly active in the market. As a technology that has applications from the clay on the Earth to the soil on the moon, superconducting magnetic separation has yet to become widely used.

International Nuclear Information System (INIS)

Full text: Pigments possessing the ability to confer high solar reflectance have received considerable attention in recent years. The inorganic class of NIR reflective pigments are mainly metal oxides and are primarily employed in two applications: (i) visual camouflage and (ii) reducing heat build up. More than half of the solar radiation consists of near-infrared radiation (52%), the remaining being 43% visible light and 5% ultraviolet radiation. Over heating due to solar radiation negatively affects comfort in the built environment and contributes substantially to electrical consumption for air conditioning and release of green house gases. A pigment which has strong reflections in the NIR region (780-2500 nm) can be referred to as a 'cool' pigment. However, most of the NIR reflective inorganic pigments particularly yellow (eg. cadmium yellow, lead chromate, chrome titanate yellow etc.) contain toxic metals and hence their consumption is being limited. Replacing them with ...

Science.gov (United States)

Kinetic reaction mechanisms have a hierarchical smacture with mechanisms for complex fuels built up on sub-mechanisms for simple fuel molecules ...

UK PubMed Central (United Kingdom)

The chloroplast and cytoplasmic isoenzymes of phosphoglycerate kinase (PGK) (EC. 2.7.2.3) from Hordeum vulgare leaves have been separated and purified for the first time to apparent...Full Text Available

Science.gov (United States)

(accumulates & stores brine for disposal). Separator. (separates water from purge gases). ? Purge pump periodically vent ... Reactor Health. Sensor. ( verifies reactor is operating w/n limits) ... Waste and Hygiene Compartment ...

International Nuclear Information System (INIS)

A pretreatment flowsheet was tested for separating key radionuclide components from the sludge stored in one of the high level waste tanks (B-110) at the Hanford Site; this sludge resulted primarily from the bismuth phosphate process, which was one of the three major plutonium separation processes used at Handford. This test involved (1) washing with water, (2) caustic leaching, (3) acid dissolution, (4) separation of transuranic elements (TRUs) by extraction with octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide(CMPO), (5) separation of Sr by extraction with di-t-butylcyclohexano-18-crown-6, (6) separation of Cs from the acid-dissolved sludge solution by treatment with ammonium molybdophosphate (AMP), and (7) separation of Cs from the sludge wash and caustic leach solutions by ion exchange using a phenol-formaldehyde resin (CS-100). The results of the ...

Energy Technology Data Exchange (ETDEWEB)

Apparatus and method for selective measurement of tritium oxide in an environment which may include other radioactive components and gamma radiation, the measurement including the selective separation of tritium oxide from a sample gas through a membrane into a counting gas, the generation of electrical pulses individually representative by rise times of tritium oxide and other radioactivity in the counting gas, separation of the pulses by rise times, and counting of those pulses representative of tritium oxide. The invention further includes the separate measurement of any tritium in the sample gas by oxidizing the tritium to tritium oxide and carrying out a second separation and analysis procedure as described above.

Science.gov (United States)

... However, the solution of the Stefan problem in this context becomes abruptly complicated, since within each zone, the differential equations ...

Science.gov (United States)

... PRC's President Jiang Zemin promised, under all circumstances and despite political differences, to protect fully Taiwanese business interests on ...

Science.gov (United States)

Seven papers were presented at the meeting. A separate abstract was prepared for each paper. (LCL)

Energy Technology Data Exchange (ETDEWEB)

Magnetic separation of several classes of antibiotics was investigated using electrochemical magnetic seeding. Electrocoagulation with a sacrificial anode followed by addition of magnetite particles was applied for the magnetic seeding of antibiotics. With electrochemical magnetic seeding using an iron anode, tetracycline antibiotics (oxytetracycline, chlortetracycline, doxycycline and tetracycline) and cephalosporin antibiotic (cefdinir) were rapidly removed from synthetic wastewater by magnetic separation using a neodymium magnet. Iron and aluminium anodes were suitable for magnetic seeding of the antibiotics. The results indicated that the ability of antibiotics to form strong complex with iron and aluminium allowed the higher removal by magnetic separation. This method would be appropriate for rapid treatment of antibiotics in wastewater.

Energy Technology Data Exchange (ETDEWEB)

Separate abstracts were prepared for thirteen papers. Two papers were abstracted previously for EDB. (MHR)

KoreaScience (Korea)

Full Text Available

Science.gov (United States)

Group for Aerospace Research and Development (AGARD) symposium and continue to ...... of vertical structures and flow separation within the tip, platform, ...

Energy Technology Data Exchange (ETDEWEB)

Separate entries are individually indexed.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

On-power refuelling is an integral feature of PHWR units. The most notable aspect of refuelling system of 540 MWe PHWR (TAPP-3 and 4) is that the FM Head is based on rack and pinion mechanism for B-ram and C-ram of Ram assembly. Latch ram used during plug operations, is assembled in between B-ram and C-ram and is moved by a ballscrew driven by oil hydraulic motors. This unique design has been employed for the first time in a PHWR unit. In comparison, B-ram is ballscrew driven and C-ram is moved by heavy water hydraulic force in FM Heads of 220 MWe PHWR units. Over the years, a number of design improvements have been carried out in the 220 MWe Fuelling Machines to meet the challenge of increasing demands of higher refuelling rates. However, in 540 MWe unit, the average refuelling rate for an equilibrium core is nearly twice that of 220 MWe units. Apart from other assemblies in FM Head, the performance of Ram assembly plays a key role in meeting this demand. The ...

International Nuclear Information System (INIS)

The present state of knowledge on the influence of stray radiation on image quality and its physical description and quantification is summarized. Experimental results on the influence of physical parameters on the fraction of scattered radiation and the effect of scatter reduction by air gap technique and secondary radiation grids are committed. Open theoretical and practical problems and the limitations of common methods of scatter reduction are pointed out. (author).

Energy Technology Data Exchange (ETDEWEB)

The interest in efficient solar collector design has stimulated investigation of two-dimensional (trough-like) cavity structures. A novel principle for designing cavity enclosures is described. The present method maintains high transmission albeit at the expense of some concentration in the presence of gaps as large as the radius between reflector and receiver. The new method can be applied to advantage to nonimaging concentrator design as well as to line focus concentrators.

International Nuclear Information System (INIS)

A review of fission product yields and delayed neutron data for Np-237, Pu-242, Am-242m, Am-243, Cm-243 and Cm-245 has been undertaken. Gaps in understanding and inconsistencies in existing data were identified and priority areas for further experimental, theoretical and evaluation investigation detailed. (author)

UK PubMed Central (United Kingdom)

We demonstrate that expression of the UGA1, CAN1, GAP1, PUT1, PUT2, PUT4, and DAL4 genes is sensitive to nitrogen catabolite repression. The expression of all these genes, with the exception of UGA1...Full Text Available

International Nuclear Information System (INIS)

Photonic band gap structures with single or multiple defects show potential for use in single-beam and multi-beam klystrons and particle accelerators. The primary concerns are the coupling between the modes at each individual defect site and the damping of unwanted higher order modes. A conceptual design of a PBG based, multi-beam klystron and methods to damp HOMs and to cool and tune the structure are presented.

Energy Technology Data Exchange (ETDEWEB)

Experimentally it is found that at constant temperature the order-parameter relaxation time, tausub(..delta..), decreases with increasing power of the microwaves, coupled into a superconducting strip. If the same increase in critical current, that corresponds with a given power of the microwaves, is obtained by lowering the temperature, the decrease in tausub(..delta..) is smaller. This reflects the fact that quasiparticles are removed more efficiently from the gap edge by microwaves than by lowering the temperature in equilibrium. A modified time-dependent Ginzburg-Landau equation is shown to describe these results adequately.

Wastenet

... (restricted)] 2009, Volume 39, Issue 5 523-529 Parents, peers, or school inputs: Which components of school outcomes are capitalized into house value? by Brasington, David M. & Haurin, Donald R. [Downloadable! (restricted)] 530-541 Trade liberalisation and agglomeration with firm heterogeneity: Forward and backward linkages by Okubo, Toshihiro [Downloadable! (restricted)] 542-552 Alternative measures of homeownership gaps across segregated ...

UK PubMed Central (United Kingdom)

1. Using a grease-gap recording technique we have investigated the effects of some antagonists of P2-purinoceptors on the depolarization of the rat isolated superior cervical ganglion evoked by 100...Full Text Available

International Nuclear Information System (INIS)

The defect-induced electron lifetime and energy-gap anisotropy effects on the T/sub c/ of the A-15 compounds are examined. A self-consistent model calculation demonstrates that the various defect dependences of T/sub c/ can be qualitatively understood in terms of the electron-lifetime effect.

CERN Document Server

We argue that the occurrence of late-time acceleration can conveniently be described by first-order general relativity covariantly coupled to fermions. Dark energy arises as a gravitationally driven BCS condensate of fermions which forms in the early universe. At late times, the gap and chemical potential evolve to have an equation of state with effective negative pressure, thus naturally leading to acceleration.

Energy Technology Data Exchange (ETDEWEB)

(1) To determine the accuracy of computed tomography (CT) in the evaluation of ligament tear and avulsion in patients with tibial plateau fracture. (2) To evaluate whether the presence or severity of fracture gap and articular depression can predict meniscal injury. A fellowship-trained musculoskeletal radiologist retrospectively reviewed knee CT and MRI examinations of 41 consecutive patients presenting to a level 1 trauma center with tibial plateau fractures. Fracture gap, articular depression, ligament tear and footprint avulsions were assessed on CT examinations. The MRI studies were examined for osseous and soft tissue injuries, including meniscal tear, meniscal displacement, ligament tear, and ligament avulsion. CT demonstrated torn ligaments with 80% sensitivity and 98% specificity. Only 2% of ligaments deemed intact on careful CT evaluation had partial or complete tears on MRI. Although the degree of fracture gap ...

Energy Technology Data Exchange (ETDEWEB)

The authors investigate the breakdown luminescence spectra in reverse-biased p-n heterojunctions based on gallium and aluminum phosphides and arsenides for the purpose of determining their behavior as lasing and photodetection materials. Data are given on temperature coefficients, band gap structure, bremsstrahlung, hot carrier mobility and photon emission, and transition and recombination parameters.

International Nuclear Information System (INIS)

The separation, concentration, and determination of trace elements in iron ores are described. After the sample has been dissolved, the iron is separated by liquid-liquid extraction with a liquid cation-exchanger, di-(2-ethylhexyl) phosphoric acid. The trace elements aluminium, cadmium, calcium, chromium, cobalt, copper, lead, magnesium, manganese, mercury, potassium, sodium, vanadium, and zinc are determined in the aqueous phase by atomic-absorption spectrophotometry.

Energy Technology Data Exchange (ETDEWEB)

Tetracycline in solution of benzyl alcohol was used as an extracting agent to separate uranium from interfering elements in the determination of uranium and of isotopic ratio sup(235)U/sup(238)U by neutron activation analysis. Separation gives a recovery of 97% for uranium and the interferences from matrices of pitchblende and monazite are eliminated.

International Nuclear Information System (INIS)

Research highlights: #-># Red mud residues (RM) were disposed in alumina production. #-># Utilization of Red mud residues was affected by its iron content. #-># Superconducting magnetic separation (HGSMS) was used in iron separation from RM. #-># RM with high and low iron contents were separated in HGSMS. - Abstract: The disposal of bayer red mud tailings now seriously threats the environment safety. Reduction and recycling of red mud is now an urgent work in aluminum industry. High gradient superconducting magnetic separation (HGSMS) system was applied to separate the extreme fine RM particles (<100 #mu#m) into high iron content part and low iron content part. Two sorts of RM were fed in the HGSMS. The iron oxide contents in concentrates were about 65% and 45% when RM 1 and RM 2 were fed respectively. Meanwhile, the residues contained 52.0% or 14.1% iron oxide in ...

Science.gov (United States)

... MECHANICAL PROPERTIES, *COPOLYMERS, *SOFT TISSUES, *GELS, *BIOMIMETICS, ISOPRENE, WOUND BALLISTICS, STYRENE PLASTICS ...

Science.gov (United States)

... Accession Number : ADA136144. Title : Characteristics of the Mechanical Properties and the Fractures of an Alpha Beta Titanium Alloy,. ...

International Nuclear Information System (INIS)

The role of helium in a process of embrittlement and hardening of RAFM steels was investigated in EUROFER97 based experimental heats, ADS2, ADS3 and ADS4, that were doped with different contents of natural B and the separated 10B-isotope (0.008-0.112 wt.%). The neutron irradiation of the boron doped and the reference RAFM steels was performed in the Petten High Flux Reactor up to 16.3 dpa at different temperatures between 250 and 450 deg. C. The embrittlement behaviour and hardening was investigated by instrumented Charpy-V tests with subsize specimens. Irradiation lead to generation of 84, 432 and 5580 appm He in ADS2, ADS3 and ADS4 steels, respectively. At irradiation temperatures Tirr ? 350 deg. C the boron doped steals show progressive embrittlement and reduction of toughness with increasing helium amount. The analysis of the hardening vs. embrittlement behaviour at Tirr ? 350 deg. C reveals hardening nature of embrittlement for helium contents up to 84 appm ...

Energy Technology Data Exchange (ETDEWEB)

This thesis presents an experimental study performed on compacted loose and natural dense expansive soils using osmotic odometers. Several successive cycles were applied under three different low constant vertical net stresses. The loose soil presents a significant shrinkage accumulation while the dense one produces the swelling accumulation during the suction cycles. The suction cycles induced an equilibrium stage which indicates an elastic behaviour of the samples. At the end of suction cycles, a loading/unloading test was performed at the constant suctions for both materials. The mechanical parameters, i.e. the virgin compression index lambda(s), the apparent pre-consolidation stress p0(s) and the elastic compression index values lambda are completely dependent on the followed stress paths. The whole experimental results made it possible to define the yielding surfaces: suction limit between micro and macrostructure (Lm/M), loading collapse (LC) and saturation ...

Energy Technology Data Exchange (ETDEWEB)

Various thiol reactive compounds, including phenylarsine oxide (PheAsO) and mersalyl, activate K/sup +/ transport into respiring mitochondria. Dicyclohexylcarbodiimide (DCCD) inhibits K/sup +/ influx. In the present studies, unidirectional fluxes of K/sup +/ or Mg/sup + +/ into respiring rat liver mitochondria were measured by means of /sup 42/K or /sup 28/Mg, with samples separated from incubation media by centrifugation through silicon. Experiments show that the % stimulation of K/sup +/ influx by PheAsO (8.5 nmol/mg protein) or by mersalyl (150 ..mu..M) was the same (53-55%) for control mitochondria as for samples pretreated with DCCD (30 nmol/mg protein). This means that DCCD caused the same % inhibition of K/sup +/ flux into control mitochondria and mitochondria in the presence of PheAsO or mersalyl (36-37%). Thus, the DCCD reactive site associated with the K/sup +/ influx mechanism appears to be independent of the thiol groups(s) ...

International Nuclear Information System (INIS)

In this paper, we study the J/#psi#(#UPSILON#) production in Z boson decay in a color-singlet model (CSM). We calculate the next-to-leading-order (NLO) QCD correction to Z#->#quarkonium+QQ, the dominant contribution in the CSM, with the vector and axial-vector parts in the ZQQ vertex being treated separately. The results show that the vector and axial-vector parts have the same K factor (the ratio of the NLO result to the leading-order result) 1.13 with the renormalization scale #mu#=2m_c and m_c=1.5 GeV, and the K factor falls to 0.918 when applying the Brodsky, Lepage, and Mackenzie (BLM) renormalization scale scheme with obtained #mu#_B_L_M=2.28 GeV and m_c=1.5 GeV. By including the contributions from the next-dominant ones, the photon and gluon fragmentation processes, the branching ratio for Z#->#J/#psi#_p_r_o_m_p_t+X is (7.3-10.0)x10"-"5 with the uncertainty consideration for the renormalization scale and charm quark mass. The results are about one-half ...

International Nuclear Information System (INIS)

Experimental results of compatibility tests on ceramics-metal bonded structures performed under high heat flux conditions in splash test apparatus are reported. Emphasis is placed on results of the channel wall design and its critical operating conditions under MHD environment. The module design of one cold type and three semihot type insulators have been tested. These materials were Al_2O_3, Al_2MgO_4, LaAlO_4, MgO and Sialon ceramics. The methods of cold type ceramics-metal bonding structure were studied on Al_2O_3 and Spinel spray coating technology. The refractory metallizing and ceramics-metal graded structure manufactured by HIP technologies were applied to bonding between the MgO or LaAlO_4 and metallic cooling system. The Sialon non-bonding structure was tested with mechanical supported cooling system by shrinc fitting method. The results indicated that the bonding structures made of the MgO(MG-S) with Copper and Fe-Ni Alloy relaxation layers and MgO(MG-NC) ...

Energy Technology Data Exchange (ETDEWEB)

The vast majority of fundamental studies of metal oxide selective oxidation catalysts have been performed with single phase systems. These investigations established the basic tenents of the redox mechanism of selective oxidation and ammoxidation catalysis. By comparison, structural and kinetic investigations of multiphase oxide catalysts are less numerous because of the inherent difficulties in understanding the relative contributions of separate phases to the catalytic behavior of the composite catalyst. Some attempts have been made in the past to understand the complex chemistry of multiphase catalysts and additional important insights have been realized more recently. However, a clear understanding of the most significant catalytic interactions between individual phases of a multiphase multicomponent redox catalyst is still lacking. In an effort to provide an understanding and a physical basis for the observed synergism in multiphase oxide ...

International Nuclear Information System (INIS)

This patent describes the producing of a refractory metal wherein a sponge refractory metal is produced as an intermediate product by the use of magnesium with the incidental production of magnesium chloride, and wherein residual magnesium is separated from the magnesium chloride and from refractory metal to a vacuum distillation step which fractionally distills the magnesium, the magnesium chloride, and the metal sub-chlorides; the steps of: recovering fractionally distilled vapors of magnesium chloride and metal sub-chlorides from a sponge refractory metal; separately condensing the vapors as separately recovered; and recycling the separately recovered magnesium at a purity of at least about 96%.