CERN Document Server

We consider a Josephson junction system installed with a finite length inhomogeneity, either of microresistor or of microresonator type. The system can be modelled by a sine-Gordon equation with a piecewise-constant function to represent the varying Josephson tunneling critical current. The existence of pinned fluxons depends on the length of the inhomogeneity, the variation in the Josephson tunneling critical current and the applied bias current. We establish that a system may either not be able to sustain a pinned fluxon, or - for instance by varying the length of the inhomogeneity - may exhibit various different types of pinned fluxons. Our stability analysis shows that changes of stability can only occur at critical points of the length of the inhomogeneity as a function of the (Hamiltonian) ...

CERN Document Server

We analyze the impact of trap states in the oxide layer of a superconducting tunnel junctions, on the fluctuation of the Josephson critical current, thus on coherence in superconducting qubits. Two mechanisms are usually considered: the current blockage due to repulsion at the occupied trap states, and the noise from electrons hopping across a trap. We extend previous studies of noninteracting traps to the case where the traps have on-site electron repulsion inside one ballistic channel. The repulsion not only allows the appropriate temperature dependence of 1/f noise, but also is a control to the coupling between the computational qubit and the spurious two-level systems inside the oxide dielectric. We use second order perturbation theory which allows to obtain analytical formulae for the interacting bound states and spectral weights, limited to small and intermediate repulsions. Remarkably, it still ...

Energy Technology Data Exchange (ETDEWEB)

We report on a new experimental approach to the size estimation of the hot spot induced by ionizing particles in a Josephson tunnel junction. Here, in contrast to the case of a superconducting strip, it is possible to investigate the hot spot dynamics in absence of effects due to the heating induced by the bias current. The reported experiment is based on the motion of Abrikosov vortices, trapped in the thin films constituting the junction electrodes, under 5.6 MeV {alpha}-particle irradiation. The fast time evolution of a hot spot, combined with the presence of Abrikosov vortices, produces a change of the static magnetic field in the junction area and thus a change of the critical current value, I{sub c}. Measurements of I{sub c} during the {alpha}-particle irradiation and in presence of trapped Abrikosov vortices allow to determine the rate of appearance of those I{sub c} changes. The behavior of the ...

Science.gov (United States)

This report discusses the following topics on superconductivity: nonlinearities in hard superconductors such as surface impedance of a type II superconductimg half space and harmonic generation and intermodulation due to alternating transport currents; and nonlinearities in superconducting weak links such as harmonic generation by a long Josephson Junction in a superconducting slab.

Energy Technology Data Exchange (ETDEWEB)

This paper reports on superconductor-semiconductor-superconductor (S-N-S) weak-link junctions with the normal layer of Si or InSb thin films were prepared by using focused ion beam (FIB), and electrical properties were measured. Whereas InSb thin films on single crystals did not have an intrinsic mobility, S-N-S junction with InSb shows the characteristics of Josephson S-N-S junction. A 200nm-thick film of InSb deposited on MgO had a mobility of 83 cm{sup 2}.V {center dot} s and a carrier density of 6.5 {times} 10{sup 17} cm{sup {minus}3} at 4.2K. The coherence length {xi}{sub n} was computed to be 17 nm from these experimental data, and we obtained critical superconducting current Ic of 100 {mu} A for the S-N-S junction which had a line width of 10{mu} m and a channel length of 20 nm.

Science.gov (United States)

... decoherence. Descriptors : *QUANTUM COMPUTING, NUCLEAR MAGNETIC RESONANCE, JOSEPHSON JUNCTIONS. Subject ...

International Nuclear Information System (INIS)

We report the observation of quantum interference in superfluid 4He. The interferometer, an analog of a dc-superconducting quantum interference device (SQUID), employs a recently reported phenomenon wherein superfluid 4He exhibits Josephson frequency oscillations in an array of submicron apertures. An interference pattern is generated by reorienting the loop of the superfluid 'SQUID' with respect to the Earth's rotation vector, thereby varying the rotation flux in the loop. The experiment is performed at 2 K, a temperature 2000 times higher than previously achieved with superfluid 3He. We find that the interference exists not only when the aperture array current-phase relation is a sinusoidal function characteristic of the Josephson effect, but also at lower temperatures where it is linear and oscillations occur by phase slips. The modest requirements for the interferometer (2 K cryogenics and fabrication of apertures at ...

International Nuclear Information System (INIS)

1974. United States Taur, Y. Univ. of California, Berkeley Richards, PL Auracher,

Energy Technology Data Exchange (ETDEWEB)

This paper described the application of an AC surface probe, similar to presently used eddy current probes, to the measurement of DC transport critical currents and critical state dissipation in high {Tc} superconductors. It has been shown that the probe can provide quantitative measurement of the full field penetration in superconducting samples by measuring the response of AC induced screening currents for superconducting materials in the form of tapes with overlayers of silver. In this manner, the AC probe can be used to replace the contact DC probe for determining critical currents in a noncontacting and local manner suitable for scanning over or along the sample.

Energy Technology Data Exchange (ETDEWEB)

This paper described the application of an AC surface probe, similar to presently used eddy current probes, to the measurement of DC transport critical currents and critical state dissipation in high [Tc] superconductors. It has been shown that the probe can provide quantitative measurement of the full field penetration in superconducting samples by measuring the response of AC induced screening currents for superconducting materials in the form of tapes with overlayers of silver. In this manner, the AC probe can be used to replace the contact DC probe for determining critical currents in a noncontacting and local manner suitable for scanning over or along the sample.

International Nuclear Information System (INIS)

Most superconductors are quite sensitive to irradiation defects. Critical temperatures may be depressed, critical currents may be increased, by irradiation, but other behaviours may be encountered. In compounds, the sublattice in which defects are created is of significant importance. 24 refs.

International Nuclear Information System (INIS)

Thermally recyclable Nb point-contact Josephson junctions are investigated as low-noise mixers with an external local oscillator at 115 GHz. The best single sideband mixer noise temperature achieved is 140 ( +- 20) K with a (SSB) conversion loss of 2.4 ( +- 0.5) dB. Such rugged junctions are suitable for use in practical receivers and should give unprecedented sensitivity at the shorter millimeter wavelengths.

UK PubMed Central (United Kingdom)

BackgroundAdequate pain assessment is critical for evaluating the efficacy of analgesic treatment in clinical practice and during the development of new therapies. Yet the currently...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Improvements in critical current capacity for superconducting film structures are disclosed and include the use of a superconducting RE-BCO layer including a mixture of rare earth metals, e.g., yttrium and europium, where the ratio of yttrium to europium in the RE-BCO layer ranges from about 3 to 1 to from about 1.5 to 1.

Energy Technology Data Exchange (ETDEWEB)

Maintaining uniformity of properties over long distances is one of the fabrication problems encountered with the new high {Tc} superconductors. Uniform properties are crucial in long tapes or wires with high critical current since local nonuniformities can limit the current carrying capacity of the whole piece. Transport critical currents in high {Tc} superconductors are conventionally measured with the contact 4-point probe DC current-voltage technique. This technique requires contact with the sample and and spatially averages over the region between the two voltage contacts. Two techniques have been used to infer the critical state model. The first uses the net magnetization of a suitably shaped sample in an external magnetic field. The second combines a DC magnetic field with AC induced currents to infer spatial flux ...

International Nuclear Information System (INIS)

Josephson effect heterodyne mixers with external local oscillators are very promising low noise mm-wave receivers for applications such as radio astronomy. Experiments at 36 GHz have shown that both the noise and the conversion efficiency of mixers made using Nb point contacts are in quantitative agreement with values calculated from the resistively shunted junction (RSJ) model. Preliminary measurements at 140 GHz suggest that this agreement extends to higher frequencies. In this paper the theoretical limits to the sensitivity of such receivers are explored as a function of the signal frequency. (Auth.).

Science.gov (United States)

The relationship between processing, microstructure, and properties was studied for A-15 compounds in multifilamentary composites produced by solid-state diffusion and in thin-film samples produced by vapor deposition. Grain sizes of A-15 superconducting compounds were measured by transmission electron microscopy of multifilamentary composites reacted at various temperatures. Critical current densities at 4.2 K and fields up to 6 T were found to be similar for niobium-tin, vanadium-gallium, and vanadium-silicon of the same grain size. Study of the Cu-V-Si phase diagram led to the production of improved multifilamentary vanadium-silicon conductors. The effects of various alloying elements on A-15 layers produced by solid-state diffusion were studied. The most promising new observation was that tantalum can be incorporated into niobium-tin reaction layers, leading to an enhancement of critical currents at ...

International Nuclear Information System (INIS)

The Fast Flux Test Facility (FFTF) was designed to test fast-reactor fuels and other nonfuel materials. In its 37 reactor cycles of operations, the FFTF reactor has performed very well and successfully completed all the irradiation testings with an operating efficiency factor as high as 98%. Since FFTF is an experimental reactor, its core loading changed from cycle to cycle. Depending on the number of test assemblies in the core and their location, the core loading can change significantly from an essentially homogeneous core loading to a relatively nonhomogeneous or even highly localized heterogeneous loading. Consequently, the core reload design and initial criticality analyses were required for each operating cycle. The zero power initial critical control rod bank height was predicted before each reactor startup. The initial critical prediction depends on the reactivity conditions at the end of the previous cycle, the ...

Energy Technology Data Exchange (ETDEWEB)

Critical current density and dissipation of four sintered YBCO filaments were measured using a continuous DC power supply. Each sample exhibited somewhat different characteristics from the others even though 3 of the 4 samples are from the same batch. The data suggest that it is possible for the YBCO filament to be in a state of stable equilibrium when part of the filament is in the flux-flow state and part of the filament is in the normal state (local hot spots). This behavior may be advantageous for resistive fault current limiters because the intermediate state (partly flux-flow and partly normal) has an overall resistance much higher than that of the flux-flow state but it does not lead to thermal runaway (burnout) or excessive heating compared to a YBCO filament driven into normal state over its entire length. Two of the samples were broken as a result of local burnout.

Energy Technology Data Exchange (ETDEWEB)

Anode polarization measurement is performed in mixed solution of NaCl and NaF using SUS 304 steel to investigate whether F[sup -] promotes or inhibits pitting corrosion. Pitting corrosion does not occur in the solution of NaF only, but passive state is broken above a certain critical potential, resulting in overall dissolution. When anode polarization measurement is made in a solution of fixed concentration NaCl added with NaF, pitting corrosion is inhibited at a certain critical concentration. F[sup -] has no effect on corrosion potential in the solution up to this critical concentration. Overall dissolution occurs in the solution with higher concentration than the critical concentration, the current value at that time agrees with that in the solution of NaF alone, and no effect of Cl[sup -] is shown. The concentration range where pitting corrosion occurs and that where overall ...

Energy Technology Data Exchange (ETDEWEB)

A computational model has been developed to calculate the potential and current distributions in the electrolyte phase and on the electrode surface for a system in which a part of the anode is passivated while the rest remains in the active dissolution state. The computation employs the finite element method allied with a boundary variation and a trial and error technique. From the obtained distributions, the location of the boundary between the active and passive regions on the anode can be predicted. In the case of a crevice, this means that a critical distance into the crevice exists beyond which active corrosion (crevice corrosion) takes place. In addition to the active/passive behavior of the material, solution conductivity, applied potential at the sample's outer surface, crevice gap and depth dimensions, and passive current density influence this critical distance to different degrees. ...

International Nuclear Information System (INIS)

Multifilamentary superconductors with 2.5 micron sized NbTi filaments are being proposed for the High Energy Booster part of the SSC project. The small filament size and the large number of filaments in the superconductor strands make the fabrication a challenge, especially in view of the high critical current performance required of them. IGC has produced two 309 mm diameter prototype billets and fabricated both the 'Inner' and the 'Outer' grade strands. The production approach was based on a triple extrusion process incorporating Cu-0.6 st.% Mn as the interfilament matrix material. The results of this pilot development effort, in terms of critical current density and mechanical properties, are presented in this paper. Appropriate comparisons with past performances are made.

International Nuclear Information System (INIS)

The paper reviews the formation of minor actinides in light water and fast reactors, as well as the current status and recent improvements in the nuclear data for minor actinides, and compares recently evaluated data with experimental results. The paper also describes the qualification of nuclear data by post-irradiation analysis and integral measurements in fast critical assemblies. (author).

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.

International Nuclear Information System (INIS)

To be able to carry out review functions regulatory authorities must be able to make critical evaluations of proponent's safety cases. In Sweden the Swedish Radiation Safety Authority aims to have in place its own suite of performance assessment tools. This paper looks at the role and application of a regulator's models to important features of current modelling in a proponent's performance assessment. (authors)

Energy Technology Data Exchange (ETDEWEB)

Charge transport in disordered organic semiconductors is generally described as thermally activated hopping in a gaussian distribution of localized states. The presence of charge traps is critical to the performance of organic electronic devices, since trapped charge carriers do no longer contribute to the current flow. The trap distribution in the polymer poly(3-hexylthiophene) (P3HT) is investigated by applying the fractional thermally stimulated current technique. Thereby, a low temperatur double-peak distribution has been revealed. One of the peaks is believed to belong to the tail of the intrinsic density of states, whereas the other trap is strongly affected by exposure to oxygen. We discuss the influence of oxygen exposure time on the trap distribution.

Energy Technology Data Exchange (ETDEWEB)

This report discusses the UTR-10 reactor at Iowa State University which went critical on low enriched uranium (LEU) fuel on August 14, 1991. However, subsequent to the criticality experiments the fuel plates started to discolor. In addition, roll pins used to lift the fuel assemblies were discovered to be cracked. It was determined that these problems were due to chemical agents in the primary coolant water. The roll pins were replaced by solid stainless steel pins. The primary coolant was replaced and the reactor is currently in operation. Surveillance specimens will be used to monitor any possible future discoloration. The high enriched fuel (HEU) is being prepared for eventual shipment to a high enriched fuel receiving facility.

International Nuclear Information System (INIS)

The influence of irradiation with 2.6 MeV H and He nuclei on the superconducting properties (critical temperature Tsub(c), critical current Isub(c)) of the intermetallic compound Nb_3Sn was studied. Irradiation led to a significant lowering of Tsub(c), while Isub(c) is increasing with the radiation dose. This is assumed to be due to the formation of active pinning centres in the lattice. There is a fast drop of Isub(c) after a peak value has been reached. Annealing of the samples (600-1,000"0C) led to an almost complete recovery of the initial value of Tsub(c). X-ray diffraction showed that irradiation causes considerable distortions of the lattice while the A15 crystal structure is retained. The causes of the radiation effects related to structural defects are discussed. (GSCH).

CERN Document Server

We report on the design, fabrication and testing of two superconducting passive microwave components, a quadrature hybrid and a 20 dB directional coupler. These components are designed to be integrated with superconducting qubits or Josephson parametric amplifiers and used in quantum information processing applications. For the coupler, we measure return loss and isolation > 20 dB, and insertion loss 20 dB and insertion loss < 0.3 dB in a 10% band around 6.5 GHz. These values are within the design specifications of our application; however, we find a 7% difference between the designed and measured center frequency for the hybrid.

International Nuclear Information System (INIS)

Dosimetry is evaluated for live-line workers exposed to 50 Hz non-uniform magnetic fields from typical high-voltage transmission lines in the United Kingdom. The configurations involve twin-, triple- and quadruple-conductor transmission line bundles. Scenarios include three worker postures for the twin and triple bundles, and four postures for the quadruple bundle. The postures are selected to simulate worst case scenarios representative of work practices and result in highest values of dosimetric measures in critical organs. Only single-phase bundles are considered, as adjacent bundles of differing phase result only in a small reduction of the dosimetric measures. Reported data include various measures of the electric field and current density induced in tissues, as well as of the current density averaged over 1 cm"2 areas normal to the current flow. A value of this latter quantity of 10 mA m"-"2 is ...

Energy Technology Data Exchange (ETDEWEB)

This study effort was required as a preliminary step prior to initiation of field measurements of atmospheric dispersion in coastal regions. The Nuclear Regulatory Commission (NRC) is in the process of planning an extensive field measurement program to generate data which will serve as improved data bases for licensing decisions, confirmation of regulations, standards, and guides, and for site characterizations. The study being reported here is an effort directed to obtaining as much information as is possible from existing studies that is relevant toward NRC's objectives. For this study, reports covering research and meteorological measurements conducted for industrial purposes, utility needs, military objectives, and academic studies were obtained and critically reviewed in light of NRC's current data needs. This report provides an interpretation of the extent of existing usable information, an indication of the potential ...

Science.gov (United States)

In 2002 and again in 2003, an investigative journalist unit at ABC News transported a 6.8 kilogram metallic slug of depleted uranium (DU) via shipping container from Istanbul, Turkey to Brooklyn, NY and from Jakarta, Indonesia to Long Beach, CA. Targeted inspection of these shipping containers by Department of Homeland Security (DHS) personnel, included the use of gamma-ray imaging, portal monitors and hand-held radiation detectors, did not uncover the hidden DU. Monte Carlo analysis of the gamma-ray intensity and spectrum of a DU slug and one consisting of highly-enriched uranium (HEU) showed that DU was a proper surrogate for testing the ability of DHS to detect the illicit transport of HEU. Our analysis using MCNP-5 illustrated the ease of fully shielding an HEU sample to avoid detection. The assembly of an Improvised Nuclear Device (IND) -- a crude atomic bomb -- from sub-critical pieces of HEU metal was then examined via Monte Carlo ...

British Library Electronic Table of Contents (United Kingdom)

This paper describes industrial aspects of combined inventory management and routing in maritime and road-based transportation, and gives a classification and comprehensive literature review of the current state of the research. The literature is contrasted with aspects of industrial applications from a constructive, but critical, viewpoint. Based on the status and trends within the field, future research is suggested with regard to both further development of the research area and industrial needs. By highlighting the industrial aspects, practitioners will hopefully see the benefit of using advanced decision support systems in complex situations related to combined inventory management and routing in their business. In addition, a classification and presentation of the research should hel...

Science.gov (United States)

The dynamic response characteristics of the VAWT rotor are important factors governing the safety and fatigue life of VAWT systems. The principal problems are the determination of critical rotor speeds (resonances) and the assessment of forced vibration response amplitudes. The solution to these problems is complicated by centrifugal and coriolis effects which can have substantial influence on rotor resonant frequencies and mode shapes. This paper will describe and discuss the primary tools now in use at Sandia National Laboratories for rotor analysis. These tools include a lumped springmass model (VAWTDYN) and also finite-element based approaches. The discussion will center on the accuracy and completeness of current capabilities and plans for future research.

Energy Technology Data Exchange (ETDEWEB)

Dynamic contingency analysis is certainly a demanding task in the context of dynamic performance evaluation. This paper presents the results of a test for checking the contingency screening capability of the IPEBS method. A brazilian 1100-bus, 112-gen system was used in the test; the ranking of the contingencies based on critical clearing times obtained with IPEBS, was compared with the ranking derived from detailed time-domain simulation. The results of this comparison encourages us to recommended the use of the method in industry applications, in a complementary basis to the current method of time domain simulation. (author) 5 refs., 1 fig., 2 tabs.

Energy Technology Data Exchange (ETDEWEB)

The Fuels Material Examination Facility/Fuel Assembly Area is proposed to be used for fabrication of mixed oxide fuel to support the Fast Flux Test Facility (FFTF) tritium/medical isotope mission. The plutonium isotope mix for the new mission is different than that analyzed in the FMEF safety analysis report. A reanalysis was performed of three representative accidents for the revised plutonium mix to determine the impact on the safety analysis. Current versions computer codes and meterology data files were used for the analysis. The revised accidents were a criticality, an explosion in a glovebox, and a tornado. The analysis concluded that risk guidelines were met with the revised plutonium mix.

British Library Electronic Table of Contents (United Kingdom)

As portable electronics become more advanced and alternative energy demands become more prevalent, the development of advanced energy storage technologies is becoming ever more critical in today's society. In order to develop higher power and energy density batteries, innovative electrode materials that provide increased storage capacity, greater rate capabilities, and good cyclability must be developed. Nanostructured materials are gaining increased attention because of their potential to mitigate current electrode limitations. Here we report on the use of vertically aligned multi-walled carbon nanotubes (VA-MWNTs) as the active electrode material in lithium-ion batteries. At low specific currents, these VA-MWNTs have shown high reversible specific capacities (up to 782mAhg^-^1 at 57mAg^-...

Energy Technology Data Exchange (ETDEWEB)

'Regional climate change: hydrology and land-use' is a topic that is being intensively discussed for quite a while already. At the same time, this topic demands consequences both on the level of politics and other decision makers. We scientists bear a particular responsibility for the analysis of existing data, targeted additional research to fill information gaps, and the critical evaluation and interpretation of the obtained results. The currently gathered sub-population of the scientific community is, albeit small, quite representative of a wide spectrum of activities and can very well offer a deeper insight into the current state-of-the-art. We deliberately organized the contributions such as to offer both overviews and results from detailed projects, as well as a close proximity of very well founded results with rather provocative hypotheses. (orig.)

International Nuclear Information System (INIS)

Critical experiments have been analyzed to verify a nuclear analysis system for fast reactors used in Japan Nuclear Cycle Development Institute (JNC). The experiments were performed in a collaboration work between JNC and the Institute of Physics and Power Engineering of Russia to dispose Russian surplus weapons plutonium, focusing on the effect of the introduction of uranium-plutonium mixed-dioxide (MOX) fuel and stainless steel reflector into the current BN-600 core that is comprised of UO_2 fuel and blanket. The analysis results agreed well with measured values on most of the nuclear characteristics. The accuracies are comparable to those obtained for the conventional MOX fueled fast reactors. It suggests that the JNC analysis system can analyze accurately nuclear characteristics in uranium fueled cores as well. A significant improvement was achieved on the sodium void reactivity by employing an ultra fine group cell calculation system. A ...

Energy Technology Data Exchange (ETDEWEB)

Recently we have found a highly effective additive for the melt growth processings attaining high critical currents in YBCO superconductor. It is platinum and it behaves as an effective grain growth inhibitor for the Y{sub 2}BaCuO{sub 5} phase. Even with less than 1 wt.% doping, Y{sub 2}BaCuO{sub 5} particles becomes less than one micron in size and distribute themselves to become homogeneously embedded in the large grown YBa{sub 2}Cu{sub 3}O{sub y} grains. The sample shows large magnetic hysteresis and a typical J{sub c} value estimated by using Bean's model critical state model is 18000 A/cm{sup 2} at 77 K and 1 T. We found that rhodium has a similar remarkable effect. (orig.).

Science.gov (United States)

Not Available

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

British Library Electronic Table of Contents (United Kingdom)

Climate change and limited primary energy resources require indigenous renewable electricity generation options to change the current coal-dominated power source matrix in China. The wind power is such a solution for the above challenges, and it still has large space for improvement in China. In this paper several critical factors related to Chinese wind power were studied in details, including the wind resources, the wind turbine industry and the policies from the Chinese government. Based on the study, the perspective of wind power in China was discussed. With outstanding advantages, the offshore wind power has a bright future in China, so its main characteristics are discussed. Based on the discussions, suggestions were given to improve the development of Chinese wind power, and the gov...

CERN Document Server

Consider the flow of a thin layer of non-Newtonian fluid over a solid surface. I model the case of a viscosity that depends nonlinearly on the shear-rate; power law fluids are an important example, but the analysis here is for general nonlinear dependence. The modelling allows for large changes in film thickness provided the changes occur over a large enough lateral length scale. Modifying the surface boundary condition for tangential stress forms an accessible base for the analysis where flow with constant shear is a neutral critical mode, in addition to a mode representing conservation of fluid. Perturbatively removing the modification then constructs a model for the coupled dynamics of the fluid depth and the lateral momentum. For example, the results model the dynamics of gravity currents of non-Newtonian fluids even when the flow is not very slow.

Energy Technology Data Exchange (ETDEWEB)

The propagation of acoustic pressure perturbations in an adiabatic low-quality air/water flow were investigated both theoretically and experimentally. A linearized dispersion model is correlated with data to extract information on the behavior of interfacial momentum transfer controlled by the virtual volume coefficient. The dispersion model is examined in limiting cases of low and high frequency and related to current models for critical flow velocity. Fourier decomposition techniques are employed to predict the dispersion of measured pressure pulses and to relate data for standing waves and propagating pulses. The dispersion model is based on a two-fluid model and is the most complete model available in the literature at this time. The dispersion data presented herein is also the best available to date for low frequency (i.e., frequencies less than bubble resonance) sound propagation in bubbly air/water mixtures.

International Nuclear Information System (INIS)

This article describes the project for the installation of an additional emergency diesel generator in both Asco and Vandellos NPPs. The basic objectives of this project are to improve the availability of the emergency generation system, in order to provide greater ability to address potential contingencies, and also to increase the flexibility of the preventive periodic maintenance of the emergency diesel generators. This maintenance, that is currently a milestone of the critical path of the refueling outage, will be performed on-line. The new diesel generator will be sized to support all the loads considered in the safety case and also the consumption of its own auxiliary systems, and will be tested for operability assessment on the same periodical basis than the existing ones. The solution adopted will also permit that the N diesel generator may be connected to any bus bar class 1E in a station black-out scenario. (Author)

Energy Technology Data Exchange (ETDEWEB)

Passive films were formed on a high purity Fe-23 Cr alloy in acid sulfate solutions in the presence and absence of chloride ion. The resulting film composition was investigated by Auger depth profiling. The passivated samples were exposed to a 1M NaCl solution at a constant potential slightly above the critical pitting potential, and the current-time transient was measured in order to compare the relative stability of the different films. The results obtained suggest that the formation conditions influence the chloride content of the passive film and the breakdown behavior. Passive films formed in the presence of chloride contain and are slightly less stable towards breakdown. No chloride was found in films formed in sulfate and subsequently exposed to chloride well below the pitting potential.

Energy Technology Data Exchange (ETDEWEB)

A strong effort is currently being devoted to the investigation of defects and diffusion phenomena in silicon. This effort is not only driven by the stringent technological requirements for the processing of integrated circuits of increased complexity and miniaturization, but also by the lack of fundamental understanding of many of the critical parameters and mechanisms involved. Experimental and theoretical investigations are needed to identify the properties of the defects, the mechanisms of impurity diffusion and the strength of impurity-defect, defect-defect, and impurity-impurity interactions. This volume provides a unique and interdisciplinary forum for the discussion of experimental, theoretical and applied aspects of defects and diffusion phenomena in silicon. Topics include: defect properties and diffusion phenomena in silicon; experimental and theoretical assessments of defect properties; transient-enhanced diffusion and dopant ...

Wastenet

...comAbstract: Hepatocellular carcinoma (HCC), once thought to be a rare tumor in North America, is a rapidly increasing type of cancer in recent years in the United States. Current treatment modalities to halt the disease progression are only marginally effective. The mainstay treatment ...In addition, NM was shown to down-regulate urokinase plasminogen activator (by fibrin zymography) and up-regulate tissue inhibitors of metalloproteinases (by reverse zymography) in another HCC cell line, Sk-Hep-1. MMP-2 and MMP-9 activities were further modulated by cytokines, inducers and inhibitors, including NM. In ... Our results suggest that NM is an excellent candidate for therapeutic use in the treatment HCC by inhibiting critical parameters in cancer development and progression, such as proliferation, invasion and metastasis, and by inducing apoptosis. Last update: 2 September 2011 JavaScript seems ...

Energy Technology Data Exchange (ETDEWEB)

The book examines current experimental and clinical knowledge concerning the biological and biophysical effects of electromagnetic radiation, particularly that in the microwave range. The biophysical bases of the interaction of electromagnetic radiation with matter are reviewed with emphasis on biological systems, and the effects of radiation on critical biological systems, including the nervous, reproductive, visual and blood-forming systems are compared. Data concerning the lethal effects of nonionizing radiation is presented and characteristics of the effects of electromagnetic radiation on the whole mammalian organisms are examined. Various reactions of the neuroendocrine system to electromagnetic radiation are described, with particular attention given to the adrenal system, and the combined effects of ionizing and microwave radiation in the flight environment are discussed. Results are also presented of a series of animal experiments on ...

International Nuclear Information System (INIS)

Stemming from their unique combination of elevated strength, low density, and good overall corrosion resistance, beta titanium alloys have become attractive candidate materials for critical, high-stress, components in corrosive services. An overview of the comparative corrosion resistance of beta alloys to conventional alpha and alpha/beta titanium alloys in common industrial and aerospace service environments generally reveals attractive behavior depending on the environment and alloy composition and, in some cases, alloy condition. Expanded performance windows are especially noted for the molybdenum-rich beta alloys, particularly in regard to resisting reducing acids, stress corrosion, and high temperature localized chloride attack, along with hydrogen and oxidation resistance. Where applicable, implications of this enhanced corrosion performance on current and perspective beta alloy applications are also noted.

CERN Document Server

This paper proposes a framework based completely on Java technology. The advantages brought about by the use of Java in network management answer some critical problems existing in current systems. With this work we address several factors concerning interoperability and security in heterogeneous network environments. Specifically, we present a manager application and a multithreaded agent engine that make use of a lightweight communication mechanism for message exchange. A MIB parser is introduced to accelerate handling of incoming management requests, and the RSA public-key cryptosystem is implemented to provide both encryption and authentication features. Results, measured in terms of response time, compare favourably with other published work and standard management frameworks.

Science.gov (United States)

This article provides an historical look at how programs and practices for students with emotional or behavior disorders (E/BD) have been evaluated since 1964, leading to a codified, although not universally recognized, set of recommendations for evaluating best practices for students with E/BD set out by The Peacock Hill Working Group (1991). The authors contend that, in addition to the programmatic features of best practice, the addition of the quality indicators and standards for research in special education add a critical dimension for examining the quality of the scientific research of identified best practices. Taken together, these set of recommendations and quality indicators represent the state of the art in program evaluation for best practice and programs for students with E/BD. The goal of this article is to outline the current recommendations and apply them to current behavior intervention practices to ...

Energy Technology Data Exchange (ETDEWEB)

This paper reports on three-dimensional continuous-energy coupled neutron-gamma Monte Carlo models of the Advanced Neutron Source (ANS) final preconceptual and conceptual reference core designs developed using the Monte Carlo Neutron and Photon transport code (MCNP) Version 3b. These models contain the reactor core with control rods, the heavy water reflector tank with shutdown rods and some beam tubes, and the outer light water pool. Eighty homogenized fuel zones per fuel element are used to represent the radial and axial {sup 235}U fuel distribution. These models are the most sophisticated, physically accurate reactor physics models of the ANS currently available. The use of MCNP methods and applications to the ANS are demonstrated. Beam tube studies, coolant voiding studies, and many criticality studies have already been performed, as have studies with variance reduction techniques. In comparison with deterministic methods, MCNP proves ...

Energy Technology Data Exchange (ETDEWEB)

A low-molybdenum austenitic stainless steel (UNS S30100) has been surface implanted with molybdenum ions, using various doses of 50 keV and 140 keV ions at room temperature. It is found that in aqueous sulphate/chloride solutions similar to the constitution of sea-waters the implantation does not affect the potentiostatically-determined critical pitting potential, but does change the density and morphology of corrosion pits. Pitting initiation after the addition of chloride at a fixed potential indicates little change in the time for measurable current increase, but the rate of increase of the current is much lower for implanted material. Detailed examination using optical microscopy, scanning electron microscopy, transmission electron microscopy and selected area diffraction suggests that the pits produced in implanted material are hemispherical with smooth covers of unattacked alloy. The use of half-implanted samples ...

International Nuclear Information System (INIS)

With the objective to improve the reactor physics calculation on a 2D and 3D nuclear reactor via the Diffusion Equation, an adaptive automatic finite element remeshing method, based on the elementary area (2D) or volume (3D) constraints, has been developed. The adaptive remeshing technique, guided by a posteriori error estimator, makes use of two external mesh generator programs: Triangle and TetGen. The use of these free external finite element mesh generators and an adaptive remeshing technique based on the current field continuity show that they are powerful tools to improve the neutron flux distribution calculation and by consequence the power solution of the reactor core even though they have a minor influence on the critical coefficient of the calculated reactor core examples. Two numerical examples are presented: the 2D IAEA reactor core numerical benchmark and the 3D model of the Argonauta research reactor, built in Brasil. (author)

International Nuclear Information System (INIS)

A cell calculation code SLAROM-UF was developed to improve calculation accuracy of effective cross sections for various fast reactor types. SLAROM-UF has a capability to calculate effective cross sections in ultra fine groups of about 100,000 below 50keV and in fine groups above the energy (maximum 900 groups). Resonance interaction among the fuel, the coolant, and the structure materials can be treated accurately even in a heterogeneous cell structure. Temperature can be set up freely in a cell by the ultra fine group calculation. Improvement in nuclear characteristics was observed in the analysis of JUPITER critical experiment, as 0.1% for criticality, 4% for sodium void reactivity, several % for radial reaction rate distribution, when SLAROM-UF was used instead of the typical cell calculation code. The effect of the ultra fine group calculation is remarkable in the non-leakage term of sodium void reactivity, and that of the fine group ...

Energy Technology Data Exchange (ETDEWEB)

A-15 compounds are extremely brittle and difficult to process for practical applications. A novel processing technique was developed to greatly improve the mechanical and superconducting properties of A-15 alloys. The new processing technique can be described as follows: (1) to select compounds that can form the A-15 phase (the selected A-15 compounds in this research were Ti3Nb6Mo3Si4 and Nb99.5-(x + y)AlxSiyB0.5 alloys); (2) to rapidly solidify them into the amorphous state; (3) to anneal the quenched amorphous products into ultra fine-grained single A-15 phase. The extreme grain refinement greatly improved the flexibility and the critical current density of the alloys. The melt spinning technique was used to rapidly solidify Ti3Nb6Mo3Si4 and Nb99.5-(x + y)AlxSiyB0.5 alloys. Ti3Nb6Mo3Si4 alloys were relatively easily formed into the amorphous state. Nb3Al alloys required the addition of glass forming elements Si and B. It was found that, ...

International Nuclear Information System (INIS)

The trifluoroacetate metal-organic decomposition route to YBa_2Cu_3O_7 film growth was investigated in order to bring new insights in the growth mechanism and its dependence on processing conditions and critical current density. Precursor films were processed on LaAlO_3 substrates at different total pressure, oxygen partial pressure, water vapor partial pressure, and volume gas flow rate keeping the growth temperature at 740 "0C. The influence of these various experimental parameters on the film growth rate, which was evaluated by in situ electrical resistance measurements, was studied thoroughly. It was found that the growth rate is nearly independent of the oxygen pressure and proportional to the square root of the water pressure. Additionally, the growth rate increases with a decrease of the total pressure or an increase of the gas flow rate. An empirical multi-exponential model simulates the experimental data, however, a better ...

Energy Technology Data Exchange (ETDEWEB)

Colorectal cancer (CRC) is a highly conversed topic, particularly since implementation of screening for CRC is imminent within the U.K. Aims: The aim of this research project was to examine the diagnostic tools currently used within the UK to detect CRC and their impact on the aetiology and epidemiology of CRC. Methodology: The complexity of the research topic lent itself towards a literature review. A systematic approach of researching was therefore adopted to analyse and critically evaluate the reliability and validity of articles. Electronic databases including AMED, Cancerlit, CINHAL, the Cochrane Library, EMBASE, MEDLINE and EBM-Reviews were utilised to provide a wide spectrum of recent and relevant articles. Other research strategies involved looking for books relating to the topics, which were kept to within 6 years of publication to maintain accuracy of information. Selected websites, such as NICE, the Department of Health, NHS websites ...

UK PubMed Central (United Kingdom)

Opinion statementCritical limb ischemia (CLI), defined as chronic ischemic rest pain, ulcers, or gangrene attributable to objectively proven arterial occlusive disease, is the most advanced...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The windmill industry in Denmark is currently confronted with making a choice between competing technologies so that the role of the stimulus of state subsidies for research has lately increased in importance. The Ministry of Energy, it is claimed, must be aware of this as possibilities for making use of research results are dictated by the market and competition. The industry is not sympathetic to the idea of state research contracts with specified goals for which manufacturers must produce a technical solution. Consultancy firms should work towards solving general problems which could help the industry as a whole. Wind turbines which are cheap to produce and operate are of more interest to industry than those which are technologically advanced or of a lighter construction. It is not thought to be advantageous to concentrate the allocation of subsidies on one key project chosen by the Ministry itself, such as the current intense interest in ...

International Nuclear Information System (INIS)

Colerectal cancer (CRC) is the second commonest cancer in the Western World. Successful treatment relies significantly on accurate detection and staging of primary disease as well as the early identification of the presence and extent of recurrence. Morphological imaging techniques, particularly computed tomography (CT), are well established and widely available to carry out these tasks in addition to predicting and monitoring response to therapy. This review analyses the current inadequacies for imaging CRC and critically assesses the potential role of functional imaging with positron emission tomography (PET). It was reviewed the current literature, to use the experience from the firs 1000 PET studies carried out at the institution and the perspective of surgical colleagues. It was found little evidence for the use of 2-["1"8F]fluoro-2-deoxy-D-glucose (FDG)-PET for screening asymptomatic individuals and ...

International Nuclear Information System (INIS)

The economic value of environmental goods is commonly determined using the concepts of willingness to pay (WTP) or willingness to accept (WTA). However, the WTP/WTA observed in different countries (or between individuals) will differ according to socio-economic characteristics, in particular income. This notion of differentiated values for otherwise identical goods (say, a given reduction in mortality risk) has been criticized as unethical, most recently in the context of the 'social cost' chapter of the IPCC Second Assessment Report. These critics argue that, being a function of income, WTP/WTA estimates reflect the unfairness in the current income distribution, and for equity reasons uniform per-unit values should therefore be applied across individuals and countries. This paper analyses the role of equity in the aggregation of climate change damage estimates, using basic tools of welfare economics. It shows one way of ...

Energy Technology Data Exchange (ETDEWEB)

We fabricated lauric acid (LA) doped MgB{sub 2} wires and investigated the effects of the LA doping. For the fabrication of the LA-doped MgB{sub 2} wires, B powder was mixed with LA at 0-5 wt.% of the total amount of MgB{sub 2} using an organic solvent, dried, and then the LA-treated B and Mg powders were mixed stoichiometrically. The powder mixture was loaded into an Fe tube and the assemblage was drawn and sintered at 900 deg. C for 3 h under an argon atmosphere. We observed that the LA doping induced the substitution of C for the B sites in MgB{sub 2} and that the actual content of C increased monotonically with increasing LA doping level. The LA-doped MgB{sub 2} wires exhibited a lower critical temperature (T{sub c}), but better critical current density (J{sub c}) behavior in a high magnetic field: the 5 wt.% LA-doped sample had a J{sub c} value of 5.32 x 10{sup 3} A/cm{sup 2}, which was 2.17 times higher than that of ...

International Nuclear Information System (INIS)

Objective: To apply the obtained results from 3 stages of research in Chinese radiation protection field. Methods: Based on the identification of physical, chemical and biological qualities for element and its radionuclides under equilibrium condition, main application of these results in Chinese radiation protection field have been discussed by using reported methods in literature. Results: Based on developing elemental reference values of organs or tissues, whole body burdens and their distribution for Chinese Reference Man, discussed in the above 3 articles, current dietary elemental intakes of 42 elements have been updated, and related basis for certain important parameters of bio-kinetic model for use in radiation protection (for example, f_l, T_e and T_b) have been provided. The internal doses from primordial radionuclides and transfer coefficients of elements from environment into the critical organs of Chinese adult men have been ...

Energy Technology Data Exchange (ETDEWEB)

A solid-state precipitation process was used to prepare superconducting tapes containing an A15 phase, V/sub 3/Ga or Nb/sub 3/Al, in a ductile niobium or vanadium containing BCC matrix. Ingots weighing as large as 30 to 50 gms of V-(14 approx. 19 at. %) Ga and Nb-(13 approx. 22 at. %) Al were prepared by arc-melting, homogenized, quenched, warm-rolled over 99% into tape, and aged at temperatures in the range 600/sup 0/C to 1000/sup 0/C to precipitate the superconducting A15 phase. The features demonstrated by the process are very attractive for practical applications. In the V-Ga system, transmission electron microscopy (TEM) studies revealed the A15 precipitates in an elongated form. However, for the Nb-Al samples, deformed and aged at 750/sup 0/C, TEM studies revealed A15 precipitation in fine equi-axed particles which formed as a semi-continuous network over sub-grain boundaries formed by the recovery of deformation-induced dislocations. In the V-Ga system, the maximum ...

Energy Technology Data Exchange (ETDEWEB)

High-spatial-resolution microfocus-based X-ray imaging technology, both real-time and film, has been used to study the thickness variation that occurs in the oxide core of silver-sheathed BSCCO ribbons produced by the powder-in-tube method. This thickness variation (also called ``sausaging``) occurs during incremental rolling and degrades the critical current densities of the ribbons. Using X-ray image data the authors determined the onset and severity of sausaging. Onset occurred at a ribbon thickness of 203 {micro}m, and the severity increased with subsequent rolling reductions. Scanning electron microscopy was used to confirm the X-ray image data. X-ray imaging provides several advantages over more traditional methods for characterizing the superconductors such as optical or scanning electron microscopy. The X-ray imaging provides nondestructive information about the entire width of the ribbon, with far greater speed, lower cost, and more ...

Energy Technology Data Exchange (ETDEWEB)

An assessment of the cooling requirements for fusion reactor components, such as the first wall and limiter/divertor, was carried out using pressurized water as the coolant. In order to establish the coolant operating conditions, a survey of the literature on departure from nucleate boiling, critical heat flux, asymmetrical heating and heat transfer augmentation techniques was carried out. The experimental data and the empirical correlations indicate that thermal protection for the fusion reactor components based on current design concepts can be provided with an adequate margin of safety without resorting to either high coolant velocities, excessive coolant pressures, or heat transfer augmentation techniques. If, however, the future designs require heat transfer enhancement techniques, experimental verification would be necessary since no data on heat transfer augmentation techniques exist for complex geometries, especially under ...

CERN Document Server

The He-shell flash convection in AGB stars is the site for the high-temperature component of the s-process in low- and intermediate mass giants, driven by the Ne22 neutron source. [...] The upper convection boundary plays a critical role during the H-ingestion episode that may lead to neutron-bursts in the most metal-poor AGB stars. We address these problems through global 3-dimensional hydrodynamic simulations including the entire spherical He-shell flash convection zone (as oposed to the 3D box-in-a-star simulations). An important aspect of our current effort is to establish the feasibility of our appoach. We explain why we favour the explicit treatment over the anelastic approximation for this problem. The simulations presented in this paper use a Cartesian grid of 512^3 cells and have been run on four 8-core workstations for four days to simulate ~5000s, which corresponds to almost ten convective turn-over times. The convection layer ...

Energy Technology Data Exchange (ETDEWEB)

Fe-sheathed MgB{sub 2} tapes with cheap stearic acid, Mg stearate and Zn stearate doping were prepared through the in situ powder-in-tube method. It is found that J{sub c}, H{sub irr} and H{sub c2} were significantly enhanced by doping. Compared to the pure tapes, J{sub c} for all the doped samples was improved by more than an order of magnitude in a high-field regime. At 4.2 K, the transport J{sub c} reached 2.02 x 10{sup 4} A cm{sup -2} at 10 T for the Zn stearate doped tapes and 3.72 x 10{sup 3} A cm{sup -2} at 14 T for the stearic acid doped samples, respectively. Moreover, at 20 K, H{sub irr} for the Zn stearate doped tape achieved 10 T, which is comparable to that of the commercial NbTi at 4.2 K. The improvement of J{sub c}-H properties in doped samples can be attributed to the increase of H{sub c2} resulting from the incorporation of C atoms into the MgB{sub 2} crystal lattice as well as a high density of flux-pinning centres.

CERN Document Server

The DARWIN mission is an Infrared free flying interferometer mission based on the new technique of nulling interferometry. Its main objective is to detect and characterize other Earth-like planets, analyze the composition of their atmospheres and their capability to sustain life, as we know it. DARWIN is currently in definition phase. This PhD work that has been undertaken within the DARWIN team at the European Space Agency (ESA) addresses two crucial aspects of the mission. Firstly, a DARWIN target star list has been established that includes characteristics of the target star sample that will be critical for final mission design, such as, luminosity, distance, spectral classification, stellar variability, multiplicity, location and radius of the star. Constrains were applied as set by planet evolution theory and mission architecture. Secondly, a number of alternative mission architectures have been evaluated on the basis of interferometer ...

International Nuclear Information System (INIS)

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

International Nuclear Information System (INIS)

In an attempt to enhance the electrical and mechanical properties of the high temperature superconducting oxides, high T(sub c) composites were prepared composed of the 123 compounds and AgO. The presence of extra oxygen due to the decomposition of AgO at high temperature is found to stabilize the superconducting 123 phase. Ag is found to serve as clean flux for grain growth and precipitates as pinning center. Consequently, almost two orders of magnitude enhancement in critical current densities were also observed in these composites. In addition, these composites also show much improvement in workability and shape formation. On the other hand, proper oxygen treatment of Y5Ba6Cu11Oy was found to possibly stabilize superconducting phase with T(sub c) near 250 K. I-V, ac susceptibility, and electrical resistivity measurements indicate the existence of this ultra high T(sub c) phase in this compound. Detailed structure, microstructure, electrical, ...

Energy Technology Data Exchange (ETDEWEB)

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that will work satisfactorily at a reasonable cost. A primary example of this is copper heap leaching, where there are no binders currently encountered in this acidic environment process. As a result, operators of many facilities see a large loss of process efficiency due to their ...

International Nuclear Information System (INIS)

Microfabrication processes for Y-Ba-Cu-O films have been investigated, using ion-beam techniques. High-T_c superconducting lines as narrow as 0.8 #mu#m have been fabricated from epitaxial YBa_2Cu_3O_7 _- _y films by Ar ion-beam etching (IBE), combined with focused ion-beam (FIB) lithography. The resulting lines, 1.3 #mu#m wide and 2 mm long, showed a zero resistance temperature of 81 K and a critical current density of 1.9 x 10"4 A/cm"2 at 77.3 K. Maskless etching was carried out using 130-keV au"+ focused ion-beam (FIB) with a 0.1-#mu#m-diameter beam. A 50-nm-thick film was patterned into 0.3-#mu#m-wide lines at a dose of 5 x "1"6 ions/cm"2. In comparison with Ar IBE, Cl_2 reactive ion-beam etching (RIBE) exhibited an enhancement effect in sputtering yield. Ion implantation with 300-keV Si"+ "+ FIB also indicated the possibility to produce submicrometer patterns by selectively modifying film properties from superconductive to normal or ...

International Nuclear Information System (INIS)

Finding environmentally friendly and cost-effective methods to remediate soils contaminated with polycyclic aromatic hydrocarbons (PAHs) is currently a major concern of researchers. In this study, a series of small-scale semi-continuous extractions - with and without in situ wet oxidation - were performed on soils polluted with PAHs, using subcritical water (i.e. liquid water at high temperatures and pressures, but below the critical point) as the removal agent. Experiments were performed in a 300 mL reactor using an aged soil sample. To find the desorption isotherms and oxidation reaction rates, semi-continuous experiments with residence times of 1 and 2 h were performed using aged soil at 250 deg. C and hydrogen peroxide as oxidizing agent. In all combined extraction and oxidation flow experiments, PAHs in the remaining soil after the experiments were almost undetectable. In combined extraction and oxidation no PAHs could be detected in the ...

International Nuclear Information System (INIS)

Brittleness and poor low-temperature thermal conductivity of A-15 compounds remain the major obstacles preventing the effective use of these superconductors in large-scale engineering applications. In order to circumvent these difficulties, a new type of ductile superconducting filamentary alloy has been developed recently by a simple metallurgical process which consists of melting the constituent elements and subsequent cold working and appropriate heat treatment. These superconducting materials are essentially Cu-base alloys containing a few percent of A-15 phase such as Nb_3Sn or V_3Ga which is in the form of fine filaments embedded in the Cu matrix. The emphasis of this work is on the formation of the A-15 phase in the Cu-base alloys and its correlation with superconducting properties such as transition temperature and critical current density. The formation of Nb_3Sn, Nb_3Al, V_3Si, and V_3Ga will serve as examples to illustrate the ...

Energy Technology Data Exchange (ETDEWEB)

A program is currently in progress at Argonne National Laboratory to evaluate and develop evaporator technology for concentrating radioactive waste streams. By concentrating radioactive waste streams, disposal costs can be significantly reduced. To effectively reduce the volume of waste, the evaporator must achieve high decontamination factors so that the distillate is sufficiently free of radioactive material. One technology that shows a great deal of potential for this application is being developed by LICON, Inc. In this program, Argonne plans to apply LICON`s evaporator designs to the processing of radioactive solutions. Concepts that need to be incorporated into the design of the evaporator include, criticality safety, remote operation and maintenance, and materials of construction. To design an effective process for concentrating waste streams, both solubility and vapor-liquid equilibrium data are needed. The key issue, however, is the ...

Energy Technology Data Exchange (ETDEWEB)

An innovative horizontal drilling system was used to install two horizontal wells as part of an integrated demonstration project at the Savannah River Site (SRS), Aiken, South Carolina. The SRS is located in south-central South Carolina in the upper Coastal Plain physiographic province. The demonstration site is located near the A/M Area, and is currently known as the Integated Demonstration Site. The Department of Energy`s Office of Technology Development initiated an integrated demonstration of innovative technologies for cleanup of volatile organic compounds (VOCS) in soils and groundwater at the SRS in 1989. The overall goal of the program is to demonstrate, at a single location, multiple technologies in the fields of drilling, characterization, monitoring, and remediation. Innovative technologies are compared to one another and to baseline technologies in terms of technical performance and cost effectiveness. Transfer of successfully demonstrated technologies ...

International Nuclear Information System (INIS)

Acetylcholine and other neurotransmitters play unique trophic roles in brain development. Accordingly, drugs and environmental toxicants that promote or interfere with neurotransmitter function evoke neurodevelopmental abnormalities by disrupting the timing or intensity of neurotrophic actions. The current review discusses three exposure scenarios involving acetylcholine systems: nicotine from maternal smoking during pregnancy, exposure to environmental tobacco smoke (ETS), and exposure to the organophosphate insecticide, chlorpyrifos (CPF). All three have long-term, adverse effects on specific processes involved in brain cell replication and differentiation, synaptic development and function, and ultimately behavioral performance. Many of these effects can be traced to the sequence of cellular events surrounding the trophic role of acetylcholine acting on its specific cellular receptors and associated signaling cascades. However, for chlorpyrifos, additional ...

Science.gov (United States)

In 2000, the Accreditation Council of Graduate Medical Education (ACGME) laid out a definition of competence that included six specific areas of focus: patient care (including clinical reasoning), medical knowledge, practice-based learning and improvement, interpersonal and communication skills, professionalism, and systems-based practice. The ACGME's intention was to mandate increasingly reliable and valid assessment measures to be used by all training programs over the next decade, with the goal of providing "more credible, accurate, reliable and useful educational outcome data." In this article, the authors will review definitions of competency according to the new ACGME standards and examine the assessment tools currently available, including global evaluations, 360-degree evaluations, checklists, standardized examinations and direct observations. The authors will provide an overview of critical considerations in different assessment ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

KoreaScience (Korea)

Full Text Available

Science.gov (United States)

PMID:4060625

Energy Technology Data Exchange (ETDEWEB)

The availability of reactor-produced radioisotopes in the United States for use in medical research and nuclear medicine has traditionally depended on facilities which are an integral part of the US national laboratories and a few reactors at universities. One exception is the reactor in Sterling Forest, New York, originally operated as part of the Cintichem (Union Carbide) system, which is currently in the process of permanent shutdown. Since there are no industry-run reactors in the US, the national laboratories and universities thus play a critical role in providing reactor-produced radioisotopes for medical research and clinical use. The goal of this survey is to provide a comprehensive summary of these production capabilities. With the temporary shutdown of the Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor (HFIR) in November 1986, the radioisotopes required for DOE-supported radionuclide generators were made available at ...

Energy Technology Data Exchange (ETDEWEB)

Understanding the mechanical properties of biomedical devices is critical in predicting and preventing their failure in the body. Such knowledge is essential, for example, in the design of biomedical stents, which must undergo repeated strain over their ten year lifetimes without breaking. Computational models are used to predict mechanical response of a device, but these models are not complete; there are significant deviations from the predictions, especially when devices are subjected to repeated multi-axial loads. Improving these models requires comparisons with actual measurements of strained nitinol. Local measurements of the full strain tensor can be made using X-ray diffraction techniques, but they are currently limited to materials whose grain size is larger than the X-ray beam size or require several diffraction patterns produced by rotation of the sample. Nitinol stents are nanocrystalline, with grains smaller than any available ...

Energy Technology Data Exchange (ETDEWEB)

Recently, independent system operators (ISOs) and others have published reports on the costs of transmission congestion. The magnitude of congestion costs cited in these reports has contributed to the national discussion on the current state of U.S. electricity transmission system and whether it provides an adequate platform for competition in wholesale electricity markets. This report reviews reports of congestion costs and begins to assess their implications for the current national discussion on the importance of the U.S. electricity transmission system for enabling competitive wholesale electricity markets. As a guiding principle, we posit that a more robust electricity system could reduce congestion costs; and thereby, (1) facilitate more vibrant and fair competition in wholesale electricity markets, and (2) enable consumers to seek out the lowest prices for electricity. Yet, examining the details suggests that, sometimes, there will be ...

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. The presence of fins enhanced the two-phase ...

International Nuclear Information System (INIS)

The Chinese government has enacted policies to promote alternative vehicle fuels (AVFs) and alternative fuel vehicles (AFVs), including city bus fleets. The life cycle (LC), energy savings (ES) and GHG reduction (GR) profiles of AVFs/AFVs are critical to those policy decisions. The well-to-wheels module of the Tsinghua-CA3EM model is employed to investigate actual performance data. Compared with conventional buses, AFVs offer differences in performance in terms of both ES and GR. Only half of the AFVs analyzed demonstrate dual benefits. However, all non-oil/gas pathways can substitute oil/gas with coal. Current policies seek to promote technology improvements and market creation initiatives within the guiding framework of national-level diversification and district-level uniformity. Combined with their actual LC behavior and in keeping with near- and long-term strategies, integrated policies should seek to (1) apply hybrid electric technology ...

Energy Technology Data Exchange (ETDEWEB)

The goal of this program was to increase the high-temperature strength of the H-Series of cast austenitic stainless steels by 50% and upper use temperature by 86 to 140 F (30 to 60 C). Meeting this goal is expected to result in energy savings of 38 trillion Btu/year by 2020 and energy cost savings of $185 million/year. The higher strength H-Series of cast stainless steels (HK and HP type) have applications for the production of ethylene in the chemical industry, for radiant burner tubes and transfer rolls for secondary processing of steel in the steel industry, and for many applications in the heat-treating industry. The project was led by Duraloy Technologies, Inc. with research participation by the Oak Ridge National Laboratory (ORNL) and industrial participation by a diverse group of companies. Energy Industries of Ohio (EIO) was also a partner in this project. Each team partner had well-defined roles. Duraloy Technologies led the team by identifying the base alloys that were to be ...

Science.gov (United States)

... Title : THE APPLICATION OF STEEP PULSE CURRENTS TO THE ELECTROHYDRAULIC AND MAGNETIC FORMING OF METALS. ...

UK PubMed Central (United Kingdom)

Two large, prospective, randomized, controlled trials have shown a beneficial effect of intensive insulin therapy (IIT) on the kidney function of critically ill patients. The data from these trials...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Critical properties of a fluid or fluid mixtures are important for describing fluid phase behavior, predicting physical properties, developing equations of state, and designing supercritical-fluid extraction processes, and compression and refrigeration units. The predictive capability of the Peng-Robinson-Styjek-Vera (PRSV-2) equation of state (1986) for critical properties of binary mixtures was investigated. The procedure adopted by Heidemann and Khalil (1980) and discussed by Abu-Eishah et al. (1998) was followed. An optimized value for the binary interaction parameter based on minimization of error between experimental and predicted critical temperatures was used. The standard and the average of the absolute relative deviations in critical properties are included. The predicted critical temperature and pressure for several nonpolar and polar systems agree well with experimental ...

UK PubMed Central (United Kingdom)

Expressed emotion measures, encompassing dimensions of criticism (CRIT), and emotional overinvolvement (EOI) are increasingly being used to assess the parent–child relationship in child...Full Text Available

UK PubMed Central (United Kingdom)

Vulnerable periods during the development of the nervous system are sensitive to environmental insults because they are dependent on the temporal and regional emergence of critical developmental processes...Full Text Available

UK PubMed Central (United Kingdom)

An integrated system of micro-and mini-computers is described to acquire, analyze, store and report data on the total activity of the heart of a critically ill patient. Real-time beat and rhythm diagnoses...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A liquid-fillet is formed in front of a rotor blade in the cylinder of a horizontal agitated thin-film evaporator. Its thickness varies due to the gravity while the blade revolves inside the cylinder. In the critical condition, the amplitude of the oscillation becomes infinite and the phase advances 180 degrees. Prior to the critical condition, the experimental data agrees fairly well with the predictions. Near the critical condition, the amplitutde increases and the phase advances 60 degrees. In other words, the transition to the critical condition occurs continuously. (6 figs, 1 ref)

International Nuclear Information System (INIS)

... Tohoku University, Graduate School of Engineering, Sendai, Miyagi (Japan)

International Nuclear Information System (INIS)

Monte Carlo criticality calculations have been performed for over 50 years for reactor physics and criticality safety applications. With today's faster computers, these calculations are being carried out to greater precision (smaller uncertainties) in keff, and detailed distributions of power and reaction rates are being computed routinely. This paper provides a review of the fundamental theory of Monte Carlo criticality calculations, with guidance on practical methods for: (1) assuring convergence of both keff and the source distribution, (2) minimizing the bias in keff and reaction rate distributions, and (3) dealing with the under-prediction bias in uncertainties for keff and reaction rate distributions. (authors)

Energy Technology Data Exchange (ETDEWEB)

I discuss several examples of critical phenomena in O(N) models where topological excitations play an important role at criticality. I focus particular attention on the O(2) model in 3D, where recent measurements of the vortex string length distribution in equilibrium suggest the existence of a quantitative picture of the critical behavior in terms of defects. The compatibility of this perspective with renormalization group predictions is examined.

Energy Technology Data Exchange (ETDEWEB)

The theoretical treatment of the relation between the critical angle of planar channeling and the characteristics of crystal lattice defects is carried out. The predictions are made about some typical forms of the critical angle dependence on the mean-square static displacement produced by defects, and then these predictions are detailed for the cases of homogeneous disordering, spherical clusters of point defects and dislocation loops. Analytical results are supported by the exact computer calculations for the defects in the intermetallic A-15 compounds.

Energy Technology Data Exchange (ETDEWEB)

The American National Standard, `Nuclear Criticality Safety in Operations with Fissionable Materials Outside Reactors` ANSI/ANS-8.1- 1983 provides guidance for the nuclides [sup 233]U, [sup 235]U, and [sup 239]Pu These three nuclides are of primary interest in out-of-reactor criticality safety since they are the most commonly encountered in the vast majority of operations. However, some operations can involve nuclides other than `U, `U, and `Pu in sufficient quantities that their effect on criticality safety could be of concern. The American National Standard, `Nuclear Criticality Control of Special Actinide Elements` ANSI/ANS-8.`15-1983 (Ref 2), provides guidance for fifteen such nuclides.

Energy Technology Data Exchange (ETDEWEB)

The Stockpile Stewardship Program (SSP) is a single, highly integrated technical program for maintaining the surety and reliability of the U.S. nuclear stockpile. The SSP uses past nuclear test data along with current and future non-nuclear test data, computational modeling and simulation, and experimental facilities to advance understanding of nuclear weapons. It includes stockpile surveillance, experimental research, development and engineering (D&E) programs, and an appropriately scaled production capability to support stockpile requirements. This integrated national program requires the continued use of current facilities and programs along with new experimental facilities and computational enhancements to support these programs. The Advanced Simulation and Computing Program (ASC) is a cornerstone of the SSP, providing simulation capabilities and computational resources to support the annual stockpile assessment and certification, ...

Science.gov (United States)

... Accession Number : ADD344580. Title : SQUID Eddy Current Technique Applying Conformable Eddy Current Probes,. Corporate Author : ...

Energy Technology Data Exchange (ETDEWEB)

The most relevant aspects of research and service experience with environmentally-assisted cracking (EAC) of carbon (C) and low-alloy steels (LAS) in high-temperature (HT) water are reviewed, with special emphasis on the primary pressure boundary components of boiling water reactors (BWRs). The main factors controlling the susceptibility to EAC under light water reactor (LWR) conditions are discussed with respect to crack initiation and crack growth. The adequacy and conservatism of the current BWRVIP-60 stress corrosion cracking (SCC) disposition lines (DLs), ASME III fatigue design curves, and ASME XI reference fatigue crack growth curves, as well as of the GE EAC crack growth model are evaluated in the context of recent research results. The operating experience is summarized and compared to the experimental/mechanistic background knowledge. Finally, open questions and possible topics for further research are identified. Laboratory investigations revealed ...

Energy Technology Data Exchange (ETDEWEB)

The Wendelstein 7-X (W7-X) modular stellarator is under construction at the Max-Planck-Institut fuer Plasmaphysik in Greifswald, Germany. The W7-X magnet system contains 70 coils made up from helium cooled superconducting cables in aluminium alloy (EN AW-6063) jackets. Several hundred connections of the jacket to the cable joints are made by aluminium-to-aluminium welds. Due to geometrical and thermal boundary conditions these welds cannot be accomplished free from defects. Microscopic analyses of the welds show that a variety of small flaws such as cracks and pores develop during welding. The welds have thus to be dimensioned accordingly, and appropriate weld qualification, investigation and testing has to be done in order not to jeopardise the structural integrity and leak tightness. The weld is mechanically loaded during cool-down due to the difference in thermal contractions between the GRP insulation and the aluminium, and during operation by bending moments from electromagnetic ...

Energy Technology Data Exchange (ETDEWEB)

With the end of the Cold War and the election of President Clinton, the Department of Energy (DOE) set a new course which began with the publication of its first departmental strategic plan in April 1994. Entitled ``Fueling a Competitive Economy, it provided the framework and shared vision for meeting responsibilities in energy, national security, environmental quality, and science and technology. The strategic plan was the guidepost for the formulation of the Department`s FY 1996, FY 1997, and FY 1998 budgets and was critical to the development of the Department`s Strategic Alignment Initiative, designed to save $1.7 billion over five years. This current plan, which has been significantly improved through a very close consultation process with Congress and customers stakeholders, takes DOE to the next important performance level by being more directly linked to actions and results. It defines a strategic goal for each of the Department`s four ...

Energy Technology Data Exchange (ETDEWEB)

In response to a request from DOE-SR, the current state of knowledge of the reactions between TBP and aqueous nitrate solutions is critically reviewed, and recommendations are made for the safe operation of SRS separations equipment in which this combination of chemicals may be present. The existing limits for evaporation are validated. Guidelines are presented for cases in which general limits do not apply. The rate of reaction between nitric acid and TBP appears to be controlled by the rate of TBP hydrolysis. The hydrolysis reaction produces dibutyl phosphate and n-butanol. The hydrolysis rate is a strong function of temperature, and becomes very fast at temperatures in the range 130{degrees} to 150{degrees}C. The resulting n-butanol is volatile at high temperatures, boiling at 117.5{degrees}C, but is also subject to exothermic oxidation by nitric acid or nitrates. If oxidation occurs before the n-butanol evaporates, the heat of oxidation may ...

International Nuclear Information System (INIS)

A processing technique for A-15 compounds which has improved mechanical and superconducting properties has been developed. This technique consists of rapid solidification of the alloy by the chill block spinning machine (CBSM) to form amorphous ribbons and by subsequent annealing crystallizes the stable or metastable fine grain flexible A-15 structure. The CBSM has been modified so that all the processing parameters could be controlled and optimized for each alloy composition. By the improved CBSM it was possible to form amorphous Nb_3Si, Nb_3Ge and Nb_3(AlSi) ribbons with more than 80% reproducible rate. Critical current density measurements are limited by contact resistance. A Cu plating technique was introduced in this research that made the contact resistance three orders of magnitude lower than that obtained by other methods. This plated coating also gave an additional mechanical support to the sample and acted as a shunt for thermal ...

Energy Technology Data Exchange (ETDEWEB)

Integrating technology readiness levels (TRL) into the management of engineering projects is critical to the mitigation of risk and improved customer/supplier communications. TRLs provide a common framework and language with which consistent comparisons of different technologies and approaches can be made. At Sandia National Laboratories, where technologies are developed, integrated and deployed into high consequence systems, the use of TRLs may be transformational. They are technology independent and span the full range of technology development including scientific and applied research, identification of customer requirements, modeling and simulation, identification of environments, testing and integration. With this report, we provide a reference set of definitions for TRLs and a brief history of TRLs at Sandia National Laboratories. We then propose and describe two approaches that may be used to integrate TRLs into the NW SMU business practices. In the first ...

Energy Technology Data Exchange (ETDEWEB)

Microfabrication processes for Y-Ba-Cu-O films have been investigated, using ion-beam techniques. High-{Tc} superconducting lines as narrow as 0.8 {mu}m have been fabricated from epitaxial YBa{sub 2}Cu{sub 3}O{sub 7 {minus} {ital y}} films by Ar ion-beam etching (IBE), combined with focused ion-beam (FIB) lithography. The resulting lines, 1.3 {mu}m wide and 2 mm long, showed a zero resistance temperature of 81 K and a critical current density of 1.9 {times} 10{sup 4} A/cm{sup 2} at 77.3 K. Maskless etching was carried out using 130-keV au{sup +} focused ion-beam (FIB) with a 0.1-{mu}m-diameter beam. A 50-nm-thick film was patterned into 0.3-{mu}m-wide lines at a dose of 5 {times} {sup 16} ions/cm{sup 2}. In comparison with Ar IBE, Cl{sub 2} reactive ion-beam etching (RIBE) exhibited an enhancement effect in sputtering yield. Ion implantation with 300-keV Si{sup + +} FIB also indicated the possibility to produce submicrometer patterns by ...

Energy Technology Data Exchange (ETDEWEB)

CNG vehicles suffer from an uncontrolled temperature rise of the gas inside the tank during the filling process and heat exchange with the environment leads to variable filling levels. A partly filled tank reduces the range of CNG vehicles and works as a impediment to the spreading of environmentaly more friendly CNG vehicles. The increase of the pressure inside the tank combined with a prolongation of the filling time beyond three minutes can reduce the deficit of the filling process. For economic reasons the time required for refuelling should be as short as possible without the need to operate the filling station with a critical pressure. To meet this target the current technique requires further improvement. (orig.) [Deutsch] Die betriebliche Praxis bei Tankvorgaengen von Erdgasfahrzeugen zeigt, dass waehrend des Tankvorganges die Temperatur des getankten Erdgases im Fahrzeugtank ansteigt. Waehrend und nach Beendigung des Tankvorganges ...

Science.gov (United States)

The advancement of bioprocess monitoring will play a crucial role to meet the future requirements of bioprocess technology. Major issues are the acceleration of process development to reduce the time to the market and to ensure optimal exploitation of the cell factory and further to cope with the requirements of the Process Analytical Technology initiative. Due to the enormous complexity of cellular systems and lack of appropriate sensor systems microbial production processes are still poorly understood. This holds generally true for the most microbial production processes, in particular for the recombinant protein production due to strong interaction between recombinant gene expression and host cell metabolism. Therefore, it is necessary to scrutinise the role of the different cellular compartments in the biosynthesis process in order to develop comprehensive process monitoring concepts by involving the most significant process variables and their interconnections. Although research ...

Energy Technology Data Exchange (ETDEWEB)

This paper discusses the evolution of the horizontal subsea tree and its utilization in increasingly demanding applications. Initially, the Horizontal Tree was seen as a solution for wells requiring high well maintenance, such as those using electrical downhole pumps. Today, the horizontal tree is being applied to natural drive wells because of attractive whole life economics. This raises concern in a number of areas. Tubing hanger seals are permanently exposed to well fluids, and must provide high integrity sealing. This required the development of a new type of radially energized, all metal sealing system, specifically for horizontal tree applications, suitable for oil or gas service at working pressures to 15,000 psi. In addition, horizontal tree pressure integrity depends on the master valve stem, gate and bonnet seals. The need for high seal integrity also dictates that the first master valves should be integral to the main body of the tree, to maximize dropped object protection. ...

Science.gov (United States)

Receptor interacting protein 140 (RIP140) is a coregulator for numerous nuclear receptors and transcription factors and primarily exerts gene-repressive activities on various target genes. We previously identified a spectrum of posttranslational modifications on RIP140 that augment its property and biological activity. In T(3)-triggered biphasic regulation of cellular retinoic acid binding protein 1 (Crabp1) gene along the course of fibroblast-adipocyte differentiation, we found TRAP220(MED1) critical for T(3)-activated chromatin remodeling whereas RIP140 essential for T(3)-repressive chromatin remodeling of this gene promoter. In this current study, we aim to examine whether and how RIP140 replaces TRAP220(MED1) on the CrabpI promoter in differentiating adipocyte cultures. We find increasing recruitment of RIP140 to this promoter, with corresponding reduction in TRAP220(MED1) recruitment during the T(3)-repressive phase. We also uncover direct ...

Science.gov (United States)

The kinetics of benzoate degradation by the anaerobic syntrophic bacterium, Syntrophus buswellii, was studied in coculture with Desulfovibrio strain G11. The threshold value for benzoate degradation was dependent on the acetate concentration with benzoate threshold values ranging from 2.4 [mu]M at 20 mM acetate to 30.0 [mu]M at 65 mM acetate. Increasing acetate concentrations also inhibited the rate of benzoate degradation with a apparent K[sub i] for acetate inhibition of 7.0 mM. Lower threshold values were obtained when nitrate rather than sulfate was the terminal electron acceptor. These data are consistent with a thermodynamic explanation for the threshold, and suggest that there is a minimum Gibbs free energy value required for the degradation of benzoate. An acetoacetyl-CoA thiolase has been isolated from Syntrophomonas wolfei; it is apparently a key enzyme controlling the synthesis of poly-B-hydroxyalkanoate from acetyl-CoA in this organism. Kinetic characterization of the ...

Energy Technology Data Exchange (ETDEWEB)

Rhodium (Rh) is a critical component of current automotive three-way catalysts (TWCs), particularly with regard to NO{sub x} and CO conversion at rich and stoichiometric air-fuel ratios (A/F). Rh supported on CeO{sub 2} was active for NO{sub x} and CO conversions but could be deactivated easily by high temperature aging. The cause of the deactivation is ascribed to the sintering of CeO{sub 2}. ZrO{sub 2} incorporation into CeO{sub 2} is reported to have high thermal durability in terms of oxygen storage capacity (OSC). There has been no report showing direct experimental evidence that Rh-loaded on CeO{sub 2}-ZrO{sub 2} mixed oxides induced effects on TWC performance improvement in the actual automotive exhaust. In the present paper, the Rh-CeO{sub 2} interaction contributing to NO{sub x} reduction and the catalytic behavior of Rh-loaded CeO{sub 2}-ZrO{sub 2} mixed oxide is addressed. Incorporating CeO{sub 2}-ZrO{sub 2} into a catalyst offered ...

Energy Technology Data Exchange (ETDEWEB)

A necessary condition for crevice corrosion is that a crevice former create a sufficiently tight, restricted geometry on the metal surface to support the development of critical crevice chemistry. Crevice corrosion is affected by the crevice geometry (tightness) and the properties of the crevice former. The objective of this study is to determine the effect of the crevice former material on the evolution of localized corrosion-damage. A standard crevice corrosion test method is modified by (a) the use of ceramic, metal or polymer materials as the crevice former and (b) the variation of size and shape of the crevice. This study focuses on the post initiation stage of crevice corrosion and addresses factors that may limit the initiation of localized corrosion and also slow or stop the continued propagation of corrosion. Controlled crevice corrosion tests are performed under aggressive, accelerated conditions on Ni-Cr-Mo alloy C-22 and other alloys for comparison. ...

International Nuclear Information System (INIS)

We review the current status of Andreev reflection spectroscopy on the heavy fermions, mostly focusing on the case of CeCoIn5, a heavy-fermion superconductor with a critical temperature of 2.3 K. This is a well-established technique to investigate superconducting order parameters via measurements of the differential conductance from nanoscale metallic junctions. Andreev reflection is clearly observed in CeCoIn5 as in other heavy-fermion superconductors. Considering the large mismatch in Fermi velocities, this observation seemingly appears to disagree with the Blonder-Tinkham-Klapwijk (BTK) theory. The measured Andreev signal is highly reduced to the order of maximum ?13% compared to the theoretically predicted value (100%). The background conductance exhibits a systematic evolution in its asymmetry over a wide temperature range from above the heavy-fermion coherence temperature down to well below the superconducting transition temperature. ...

International Nuclear Information System (INIS)

Full text: The transmutation of nuclear waste to reduce the burden on a geological repository is a relevant topic within the Program of Nuclear Safety Research of the Research Centre Karlsruhe. Several studies have confirmed that a high efficiency of transmutation of actinides is reached in fast neutron spectrum reactor system. Therefore, an important effort is dedicated to the study of transmutation strategies with different fast reactors and their associated technologies. Moreover, in international contexts as Generation IV International Forum (GIF) and Sustainable Nuclear Energy Technology Platform (SNETP), fast reactors are considered in the frame of sustainable development of nuclear energy and reduction of waste. The systems that are currently under investigation, in the frame of the different fuel cycle scenarios, are liquid metal cooled and gas cooled fast reactors as well as Accelerator Driven Sub-critical Transmutation devices (ADS). ...

International Nuclear Information System (INIS)

Steam generators (SG) are among the most critical components of pressurized water Nuclear Power Plants (NPP). SG tubes must provide a reliable pressure boundary between the primary and secondary cooling water. It is because that any leakage from tube defects could result in the release of radioactivity to the environment. Thus degradations of steam generators tubes should be monitored and inspected periodically under nuclear regulatory. In-service inspections of SG tubes are carried out using eddy current test (ECT) and the defected tubes are usually plugged. Because the radioactivity in the internal of SG chambers limits free access of human worker, remote manipulators are required. In South Korea, Manipulators such as the Zetec SM series and the Westinghouse ROSA series have been used. Such manipulators are rigidly mounted to manways or tube sheets of SG. Confusions for the inspected tubes may occur from deflection of the manipulators. To ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Science.gov (United States)

... Accession Number : ADD321199. Title : OPTIMIZATION OF EDDY CURRENT PROBES FOR NDT OF CARBON FIBER COMPOSITES. ...

Science.gov (United States)

... HARDENED CUP AND CARBURIZED AND HARDENED CORES HAVE BEEN PROFILED USING 2 TYPES OF EDDY CURRENT PROBES. ...

Science.gov (United States)

... ADA185428. Title : Combustible Cartridge Cases, an Account of the Current Technology and Proposals for Future Development. ...

Energy Technology Data Exchange (ETDEWEB)

Geologic sequestration is currently being practiced and scientifically evaluated as a critical component in a broad strategy, comprising new practices and technologies, for mitigating global climate change due to anthropogenic emissions of CO2. Demonstrating that geologic sequestration of CO2 is safe and effective, and gaining public acceptance of sequestration technologies are critically important in meeting these global climate change challenges. Monitored field-scale demonstrations of geologic sequestration of carbon dioxide will contribute greatly toward growing trust and confidence in the technology; however, pilot demonstrations ultimately will not be the norm for new geological sequestration deployments. Instead, scientists, engineers, regulators, and ultimately the public will rely on numerical simulations to predict the performance of geologic repositories for carbon dioxide sequestration. The U.S. Department of ...

Energy Technology Data Exchange (ETDEWEB)

The primary objective of the work was to establish and verify cost and performance parameters for integrated concepts in which agricultural and other biomass derived pyrolysis oils are utilised as fuel for small scale heat and power production. Production of non-food value-added products was also considered. The cost and performance studies were carried out in Spain, Denmark, and Finland, using olive oil farming residues, straw, and rapeseed oil pressing residues and straw as fuels for pyrolysis, respectively. Use of forest residue wood fuel was also considered in the Finnish vase. A rather wide selection of biomasses was therefore studied within the project. The secondary objective was to generate experimental data to verify and support the critical features within these concepts. Experimental work, modelling, and techno-economic assessments were carried out within the project. The experimental part included: Determination of flash pyrolysis balances in a PDU-unit ...

International Nuclear Information System (INIS)

The compressive and torsional buckling behavior of carbon nanotube bundles at room temperature is examined with classical molecular dynamics simulation. The critical compressive load and stiffness of a single carbon nanotube in the bundle are found to be similar to those of individual carbon nanotubes. However, the critical torsional moment and stiffness of a single carbon nanotube in the bundle are found to be higher than those of individual carbon nanotubes. In addition, this study demonstrates that van der Waals interactions between the nanotubes in the bundle significantly affect the critical compressive load of the nanotube bundle.

Energy Technology Data Exchange (ETDEWEB)

Monte Carlo methods have been used to compute k{sub eff} and the fundamental mode eigenfunction of critical systems since the 1950s. While such calculations have become routine using standard codes such as MCNP and SCALE/KENO, there still remain 3 concerns that must be addressed to perform calculations correctly: convergence of k{sub eff} and the fission distribution, bias in k{sub eff} and tally results, and bias in statistics on tally results. This paper provides a review of the fundamental problems inherent in Monte Carlo criticality calculations. To provide guidance to practitioners, suggested best practices for avoiding these problems are discussed and illustrated by examples.

UK PubMed Central (United Kingdom)

Though notes in electronic medical record systems (EMRs) have advantages, they are often criticized for their unattractive and unprofessional appearance. We sought to identify notes regarded by physicians...Full Text Available

International Nuclear Information System (INIS)

(1977). United States Thomas, JT Tang, JS Oak Ridge National Lab., TN San

International Nuclear Information System (INIS)

Apart from conventional phase transitions driven by the thermal effects, quantum phase transitions generated by quantum fluctuations have their own mechanisms that are reflected in critical phenomena. Quantum phase transitions have an origin from spontaneous symmetry breaking commonly to thermal phase transitions. Even in this case, inherent quantum fluctuations substantially modify and yield new aspects. Quantum phase transitions have, however, another mechanism caused by topology changes, which gives completely new characters. Recently, a mechanism which connects these two has been found. Proimities from first-order transitions and phase separatins as well as from multiphase coexistence also generate characteristic and unconventional quantum criticalities. Understanding novel quantum criticalities offers a firm basis of recent active researches on fields such as magnetism, ferroelectricity and metal-insulator transitions ...

UK PubMed Central (United Kingdom)

For some neurotoxic chemicals, neurobehavioral effects are now considered to be among the most sensitive end points yet detected, particularly if exposures occur during critical windows of vulnerability....Full Text Available

CERN Document Server

The celebrated Kuramoto model captures various synchronization phenomena in biological and man-made dynamical systems of coupled oscillators. It is well-known that there exists a critical coupling strength among the oscillators at which a phase transition from incoherency to synchronization occurs. This paper features three contributions. First, we characterize and distinguish the different notions of synchronization used throughout the literature and formally introduce the concept of phase cohesiveness as an analysis tool and performance index for synchronization. Second, we review the vast literature providing necessary, sufficient, implicit, and explicit estimates of the critical coupling strength in the finite and infinite-dimensional case. Finally, we present the first explicit necessary and sufficient condition on the critical coupling strength to achieve synchronization in the finite-dimensional Kuramoto model for an ...

Energy Technology Data Exchange (ETDEWEB)

A brief article considers the possible result of the enquiry into Nirex`s plan to build an underground rock laboratory at Sellafield in relation to radioactive waste disposal in the UK. (UK).

UK PubMed Central (United Kingdom)

Contractile vacuole complexes are critical components of cell volume regulation and have been shown to have other functional roles in several free-living protists....Full Text Available

Science.gov (United States)

... Hutchinson, V. H., A. Vinegar, and R. J. Kosh. 1966. Critical thermal maxima in turtles. Herpetologica 22: ... ...

Energy Technology Data Exchange (ETDEWEB)

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

UK PubMed Central (United Kingdom)

ObjectiveAngiography remains a critical component for diagnostic imaging and therapeutic intervention in peripheral arterial disease (PAD). The goal of this study...Full Text Available

UK PubMed Central (United Kingdom)

Behavioral responses to wind are thought to play a critical role in controlling the dispersal and population genetics of wild Drosophila species1,Full Text Available

UK PubMed Central (United Kingdom)

OBJECTIVESIntroduce pediatric delirium and provide understanding of acute brain dysfunction with its classification and...Full Text Available

Science.gov (United States)

... Uninterrupted access to and use of critical infrastructure in the Arabian Gulf region are key to the successful prosecution of the Global War on Terror ...

UK PubMed Central (United Kingdom)

Background:To determine nutrient requirements by the carbon oxidation techniques, it is necessary to know the fraction of carbon dioxide produced during the oxidative...Full Text Available

UK PubMed Central (United Kingdom)

The challenges of lung cancer radiotherapy are intra/inter-fraction tumor/organ anatomy/motion changes and the need to spare surrounding critical structures. Evolving radiotherapy technologies, such...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundMitochondrial DNA (mtDNA) is being analyzed by an increasing number of laboratories in order to investigate its potential role as an active marker of tumorigenesis...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

6 mm diameter current leads made of M1, M3 copper and L62 brass are tested for extension of operation range of current leads supplying superconducting devices submerged into the cryostat. Data characterizing the effect of material purity on lead superheating are obtained. A theoretical model permitting to obtain analytical dependences for calculating the current lead maximum temperature is proposed and the possibility of its decrease by increasing current lead diameter in the hot part is considered.

Energy Technology Data Exchange (ETDEWEB)

The high-speed direct-injection diesel engine for passenger cars has been a resounding success in the marketplace in the last few years. This was due to an intensive development process as a result of which the direct-injection diesel engine for passenger cars is currently setting new standards with regard to performance and fuel consumption in spite of the constant tightening of emission regulations. Of particular importance in this context is exhaust gas recirculation (EGR). This technology permits a considerable reduction in nitrogen oxide emissions, which are especially critical in the case of the direct-injection diesel engine. In addition, continuing development of supercharging technology, in particular the turbocharger with variable turbine geometry, have allowed further improvement of the full-load behaviour and the engine response and a considerable reduction in the fuel consumption of direct-injection diesel engines. This FVV paper ...

Energy Technology Data Exchange (ETDEWEB)

The ''Enabling & Information Technology To Increase RAM for Advanced Powerplants'' program, by DOE request, was re-directed, de-scoped to two tasks, shortened to a 2-year period of performance, and refocused to develop, validate and accelerate the commercial use of enabling materials technologies and sensors for coal/IGCC powerplants. The new program was re-titled ''Enabling Technology for Monitoring & Predicting Gas Turbine Health & Performance in IGCC Powerplants''. This final report summarizes the work accomplished from March 1, 2003 to March 31, 2004 on the four original tasks, and the work accomplished from April 1, 2004 to July 30, 2005 on the two re-directed tasks. The program Tasks are summarized below: Task 1--IGCC Environmental Impact on high Temperature Materials: The first task was refocused to address IGCC environmental impacts on high temperature materials used in gas turbines. This task ...

Energy Technology Data Exchange (ETDEWEB)

The study described in this report is part of a project sponsored by the Toronto Atmospheric Fund, performed at the Lawrence Berkeley National Laboratory, to assess the potential role of surface property modifications on energy, meteorology, and air quality in the Greater Toronto Area (GTA), Canada. Numerical models were used to establish the possible meteorological and ozone air-quality impacts of increased urban albedo and vegetative fraction, i.e., ''cool-city'' strategies that can mitigate the urban heat island (UHI), significantly reduce urban energy consumption, and improve thermal comfort, particularly during periods of hot weather in summer. Mitigation is even more important during critical heat wave periods with possible increased heat-related hospitalization and mortality. The evidence suggests that on an annual basis cool-city strategies are beneficial, and the implementation of such measures is ...

International Nuclear Information System (INIS)

A simple model is used to explain the decrease in superconducting critical temperature with damage observed for irradiated A-15 compounds. A truncated t-matrix approximation is used to describe the disorder along the one-dimensional transition metal chains. Three dimensionality is introduced by the inclusion of interaction between transition metal atoms on different chains. Numerical fits to experiment are discussed in the conclusion. (author).

International Nuclear Information System (INIS)

Power density measurements in the critical facility RA-8 are presented. These measurements were the first systematic use of the reactor. A measurement system was designed, built and proved for this goal. Power profiles are showed and the results are compared with calculated values. (author)

Energy Technology Data Exchange (ETDEWEB)

Institutional issues play a critical, but often overlooked, role in the implementation of renewable energy systems. This paper briefly reviews the institutional arrangements involved in deploying renewable energy from both the sender and receiver perspectives, giving the institutional basis principal characteristics, and pros and cons of each institution. It then offers several perspectives on the critical issues facing the deployment of renewable energy systems before offering a number of potential institutional based solutions. (author)

Energy Technology Data Exchange (ETDEWEB)

The critical concentrations correspond to contamination thresholds of environments over which noxious effects can occur and deteriorate soils, water and vegetation. They are defined according to the type of pollutants and their mode of action. The aim of this document is to provide a scientific framework to the policies of reduction of atmospheric pollution negotiated at Geneva`s convention. The methodology of evaluation, the results obtained for surface waters and forest soils, the perspectives of French research and the integration of French knowledge in the European database are presented. (J.S.)

International Nuclear Information System (INIS)

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

Science.gov (United States)

...Critical habitat units are depicted for Baldwin County, Alabama, on the maps below...paragraph (2) of this entry, over 2005 Baldwin County, Alabama color photography (UTM...ER30JA07.000(6) Unit 1: Fort Morgan, Baldwin County, Alabama.(i) General...

International Nuclear Information System (INIS)

The dynamics of a general Bianchi type-IX model with three scale factors is examined. The matter content of the model is assumed to be comoving dust plus a positive cosmological constant. The model presents a critical point of saddle-center-center type in the finite region of phase space. This critical point engenders in the phase space dynamics the topology of stable and unstable four dimensional tubes RxS"3, where R is a saddle direction and S"3 is the manifold of unstable periodic orbits in the center-center sector. A general characteristic of the dynamical flow is an oscillatory mode about orbits of an invariant plane of the dynamics which contains the critical point and a Friedmann-Robertson-Walker (FRW) singularity. We show that a pair of tubes (one stable, one unstable) emerging from the neighborhood of the critical point towards the FRW singularity have homoclinic transversal crossings. The ...

Energy Technology Data Exchange (ETDEWEB)

Vegetation is a key compartment of ecosystems. It contains a large part of the biodiversity at the species level. For the evaluation of critical loads, we have to separate different receptors: lower plants (algae, fungi, lichens and mosses) and vascular plants. Trees must be distinguished due to their economic value. We analyze the different changes that pollution produces on vegetation: the state of health of individuals, changes in the biology and genetics at the population level, changes in the biodiversity or the specific composition at the community level. Calculation of critical loads is based on observational or experimental studies, in more or less controlled environments. However, they cannot yet be obtained through models of vegetation changes. Some results have been acquired at the European level, mainly for critical loads for nitrogen, but these results have come mostly from Northern Europe. Moreover, only ...

Energy Technology Data Exchange (ETDEWEB)

This paper reconsiders the problem of the violation of the Jacobi identity in the algebra of currents. Such a violation has recently been claimed to occur also in the case of free fermionic current. The authors consider a regularization prescription for the corresponding double commuters consistent with the Jacobi identity.

Energy Technology Data Exchange (ETDEWEB)

The results of finite element calculations detailing the interactions of eddy currents with fine collinear slots in nonferromagnetic and ferromagnetic conductors are presented. These are applicable to both remote field eddy current inspection tools and conventional reflected impedance eddy current probes. The calculations show that, while fine slots have little interaction with collinear induced currents in nonferromagnetic conductors, there are much larger effects in ferromagnetic conductors. This is due to magnetic field interactions. The term eddy current inspection' is therefore somewhat restrictive and the much broader term electromagnetic inspection' is proposed.

British Library Electronic Table of Contents (United Kingdom)

Abstract: [public affairs, ethical currents, Ireland, social research ethics] Liam Frink is contributing editor of Ethical Currents, the AN column of the AAA Committee on Ethics.

Science.gov (United States)

... The development of various modeling methods for conventional eddy current probes (absolute, differential, two-port, etc.) has led to a general ...

Science.gov (United States)

... Accession Number : ADD336001. Title : Development of a FeCoNb Alloy to be used in Eddy Current Probes for Testing Ferromagnetic Tubes,. ...

Science.gov (United States)

... 13BRL I COMBUSTIBLE CARTRIDGE CASES: CURRENT STATUS AND FUTURE PROSPECTS FW ROBBINS J. W. COLB3URN DI ...

Science.gov (United States)

... perform the inspection in the extremely limited space between adjacent blades and at the blade root, miniature eddy current probes were developed ...

Science.gov (United States)

... Accession Number : ADA539720. Title : A Hybrid Kinetic Model of Asymmetric Thin Current Sheets with Sheared Flows in a Collisionless Plasma. ...

Energy Technology Data Exchange (ETDEWEB)

Ternary diagrams are commonly used to provide a graphic representation of equilibrium fluid phase behavior for systems as diverse as distillation columns and miscible gas floods of oil reservoirs. The phase envelope, and the position of the critical point on it, are important to enhanced oil recovery engineers who are involved with miscible gas flood design. In the past, phase equilibrium data were laboriously plotted on the ternary diagram and special graphic techniques were utilized to locate the critical point on the phase envelope. This work presents a computerized curve fitting method to generate the phase envelope from a given set of phase equilibrium data and then use the tie-line slopes to position the critical point. Experimental data are included and show excellent agreement with this new method.

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 ...

International Nuclear Information System (INIS)

Using indigenously developed computer program, coupled neutron gamma multi-group libraries have been generated from MA TXS-NJOY files. The MATXS format contains all the details for each reaction. Temperature and dilution factor dependent cross-sections have been generated and used in discrete ordinates method for benchmark studies of fast critical experiments. We have analyzed criticality benchmarks, which includes CSEWG fast critical benchmarks, "2"3"3U and Pu spheres and enriched uranium spheres using 30-group neutron cross-sections. Neutron and gamma spectra for spheres with point neutron source at the center, are also calculated with 42-group coupled neutron gamma cross-sections. (author)

International Nuclear Information System (INIS)

The report presents the results of experimental studies conducted to provide a description of the conditions which lead to the occurrence of critical heat flux (CHF), in Combustion Engineering (C-E) fuel assemblies using the C-E standard spacer grid. A CHF correlation is presented which is based on CHF data obtained in tests with electrically heated rod bundles representative of the C-E 14 x 14 and 16 x 16 array fuel assemblies. The results reported are for a uniform axial heat flux distribution. The experiments were conducted in the Medium Pressure Heat Transfer Flow Loop at the Chemical Engineering Research Laboratories at Columbia University.

KoreaScience (Korea)

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CSIR Research Space (South Africa)

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International Nuclear Information System (INIS)

The results show that the SQUID device eddy current testing system is a suitable tool for NDE. Due to the high low-frequency sensitivity of the SQUID sensor, the SQUID device eddy current testing system permits lower examination frequencies than the conventional eddy current probe system. The SQUID system enhances fault detection in even deeper materials layers. (orig./MM).

KoreaScience (Korea)

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Science.gov (United States)

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Science.gov (United States)

In this activity, students will make a turbidity current. They will discover how fluids of differing densities interact with one another, learn some ways the densities of fluids can be changed and observe how density currents transport and deposit tremendous amounts of sediment in lakes and in the ocean. Additional options allow students to create and observe different kinds of density currents.

KoreaScience (Korea)

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UK PubMed Central (United Kingdom)

The mechanisms that contribute to the extinction of previously acquired memories are not well understood. These processes, often referred to as inhibitory learning, are thought to be parallel...Full Text Available

UK PubMed Central (United Kingdom)

This paper summarizes the deliberations of a work group charged with addressing specific questions relevant to risk estimation in developmental neurotoxicology. We focused on eight questions. a) Does...Full Text Available

UK PubMed Central (United Kingdom)

A critical research priority for our field is to develop treatments that enhance cognitive functioning in schizophrenia and thereby attenuate the functional losses associated with the illness. In this...Full Text Available

UK PubMed Central (United Kingdom)

The hemagglutinin (HA) glycoprotein of influenza virus performs two critical roles during infection: it binds virus to cell surface sialic acids, and under mildly acidic conditions it induces fusion...Full Text Available

UK PubMed Central (United Kingdom)

Synaptic vesicle endocytosis is critical to maintain synaptic communication during intense stimulation. Here we describe Tweek, a conserved protein that is required for synaptic vesicle recycling....Full Text Available

UK PubMed Central (United Kingdom)

BackgroundProcessing of multimodal information is a critical capacity of the human brain, with classic studies showing bimodal stimulation either facilitating or interfering in perceptual...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The temperature dependence of the dislocation mobility threshold is investigated on the basis of a dislocation model suggested by Frenkel-Kontorova. The critical value is obtained for the stress/temperature, corresponding to the dislocation depinning from its equilibrium position. The universal behaviour of a barrier height at finite stress and temperature is revealed and investigated.

UK PubMed Central (United Kingdom)

Thyroid hormone is a critical regulator of growth, development and metabolism in virtually all tissues, and altered thyroid status affects many organs and systems. Although for many years testis...Full Text Available

UK PubMed Central (United Kingdom)

By analysis of crossovers in key recombinant families and by homozygosity analysis of inbred families, the Friedreich ataxia (FRDA) locus was localized in a 300-kb interval between the X104 gene and...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundRasbora tawarensis is an endemic freshwater fish in Lake Laut Tawar, Aceh Province, Indonesia. Unfortunately, its status is regarded as critical endangered...Full Text Available

International Nuclear Information System (INIS)

A calculation program (URA 6.F4) was elaborated on FORTRAN IV language, that through finite differences solves the unidimensional scalar Helmholtz equation, assuming only one energy group, in spherical cylindrical or plane geometry. The purpose is the determination of the flow distribution in a reactor of spherical cylindrical or plane geometry and the critical dimensions. Feeding as entrance datas to the program the geometry, diffusion coefficients and macroscopic transversals cross sections of absorption and fission for each region. The differential diffusion equation is converted with its boundary conditions, to one system of homogeneous algebraic linear equations using the box integration technique. The investigation on criticality is converted then in a succession of eigenvalue problems for the critical eigenvalue. In general, only is necessary to solve the first eigenvalue and its corresponding eigenvector, employing ...

Energy Technology Data Exchange (ETDEWEB)

Three dispersants (stearic acid, oleic acid, and poly-(12-hydroxystearic acid)) are compared for their ability to produce low-viscosity suspensions of zirconia in kerosene. Rheological measurements and sediment packing density measurements show that poly(12-hydroxystearic acid) is a better dispersant than stearic acid or oleic acid; this is explained in terms of the longer tail of the poly-(12-hydroxystearic acid) surfactant molecule. The amount of dispersant can be optimized to reduce viscosity and yield point of the suspension, and to eliminate thixotropic hysteresis. The use of a dispersion medium of lower viscosity than the dispersant makes it easy to detect when complete monolayer coverage has been achieved. The loss of pseudoplasticity, brought about by a higher degree of deflocculation, can be recovered by increasing the volume fraction of solids of a suspension and this is beneficial in the plastic forming of ceramics. Rheological measurements showed that these suspensions ...