Science.gov (United States)

of satellite, aircraft and ground-based observations. In ..... swarm traps by Utah Department of Food and Agriculture (DAF) personnel. Preliminary Results ..... the 150th anniversary of the book's publication and the 200th anniversary of Darwin's birth. ...... cold war submarine missions to find that Arctic Ocean ...

Science.gov (United States)

BAE SYSTEMS Infrared Imaging Systems. MS 209. 2 Forbes Road. Lexington, MA 02421 -7306. (781) 863-3762. (781) 863-4809 (fax) ken.overoye @lmco.com ...

British Library Electronic Table of Contents (United Kingdom)

We present an empirical model for periodic variations of diurnal and sub-diurnal Earth rotation parameters (ERPs) that was derived based on the transformation of normal equation (NEQ) systems of Very Long Baseline Interferometry (VLBI) observing sessions. NEQ systems that contain highly resolved polar motion and UT1-TAI with a temporal resolution of 15?min were generated and then transformed to the coefficients of the tidal ERP model to be solved for. To investigate the quality of this model, comparisons with empirical models from the Global Positioning System (GPS), another VLBI model and the model adopted by the conventions of the International Earth Rotation and Reference Systems Service (IERS) were performed. The absolute coefficients of these models agree almost completely within 7.5?...

CERN Document Server

We investigate the influence of lunar-like satellites on the infrared orbital light curves of Earth-analog extra-solar planets. Such light curves will be obtained by NASA's Terrestrial Planet Finder (TPF) and ESA's Darwin missions as a consequence of repeat observations to confirm the companion status of a putative planet. We use an energy balance model to calculate disk-averaged infrared (bolometric) fluxes from planet-satellite systems over a full orbital period (one year). The satellites are assumed to lack an atmosphere, have a low thermal inertia like that of the Moon and span a range of plausible radii. The planets are assumed to have thermal and orbital properties that mimic those of the Earth while their obliquities and orbital longitudes of inferior conjunction remain free parameters. Even if the gross thermal properties of the planet can be independently constrained (e.g. via spectroscopy or ...

Energy Technology Data Exchange (ETDEWEB)

The automatic interpretation of apparent resistivity curves from horizontally layered earth models is carried out by the curve-fitting method in three steps: (1) the observed VES data are interpolated at equidistant points of electrode separations on the logarithmic scale by using the cubic spline function, (2) the layer parameters which are resistivities and depths are predicted from the sampled apparent resistivity values by SALS system program and (3) the theoretical VES curves from the models are calculated by Ghosh's linear filter method using the Zhody's computer program. Two soundings taken over Takenoyu geothermal area were chosen to test the procedures of the automatic interpretation.

CERN Document Server

Cosmic ray antiprotons provide an important probe for the study of cosmic-ray propagation in the interstellar space and to investigate the existence of Galactic dark matter. Cosmic rays are hampered by the Moon, therefore a deficit of cosmic rays in its direction is expected (the so-called "Moon shadow"). The Earth-Moon system acts as a magnetic spectrometer. In fact, due to the geomagnetic field the center of the Moon shifts westward by an amount depending on the primary cosmic ray energy. Paths of primary antiprotons are therefore deflected in an opposite sense in their way to the Earth. This effect allows, in principle, the search of antiparticles in the opposite direction of the observed Moon shadow. The ARGO-YBJ experiment, in stable data taking since November 2007 with an energy threshold of a few hundreds of GeV, is observing the Moon shadow with high statistical ...

Energy Technology Data Exchange (ETDEWEB)

An important growth in the power of the photovoltaic systems connected to a grid has recently been observed. In spite of the advances in module technology, the problems in the system design increased, especially regarding the surface of the earth they occupy. In this work we propose a complete model for plant simulation with different wiring diagrams and under dynamic shading. Results obtained from simulations showed that the configuration with the lowest performance was that of only one serial-parallel group, whereas the highest efficiency corresponded to a design of groups of modules in parallel connected then in series. In general, a higher efficiency was obtained diminishing the quantity of modules in series and increasing their number in parallel. The simulation model proposed allows exploring different alternatives of wiring modules and finding the most efficient configurations for photovoltaic ...

British Library Electronic Table of Contents (United Kingdom)

The gravitational torque applied on the Earth by the other celestial bodies generates periodic variations in the orientation of the Earth's rotation axis in space which are called nutations. Observations of Earth's nutations allow for insights into the physical properties of the inner core because of the presence of a normal mode, the Free Inner Core Nutation (FICN), which is characterized by a tilt of the inner core figure and rotation axes with respect to the mantle and outer core. The frequency of the FICN is controlled by the strength of the mechanical coupling acting at the inner core boundary (ICB) and by the ability of the inner core to deform under the action of centrifugal and gravitational forces. Attenuation of the FICN reflects energy dissipated by electromagnetic (EM) and visc...

British Library Electronic Table of Contents (United Kingdom)

For the reuse of a waste salt from an electrorefining process of a spent oxide fuel, a separation of rare earth elements by an oxidative precipitation in a LiCl-KCl molten salt was tested without using precipitate agents. From the results obtained from the thermochemical calculations by HSC Chemistry software, the most stable rare earth compounds in the oxygen-used rare earth chlorides system were oxychlorides (EuOCl, NdOCl, PrOCl) and oxides (CeO2, PrO2), which coincide well with results of the Gibbs free energy of the reaction. In this study, similar to the thermochemical results, regardless of the sparging time and molten salt temperature, oxychlorides and oxides were formed as a precipitant by a reaction with oxygen. The structure of the rare earth precipitates was divided into two sha...

CERN Document Server

The Galactic Exoplanet Survey Telescope (GEST) will observe a 2 square degree field in the Galactic bulge to search for extra-solar planets using a gravitational lensing technique. This gravitational lensing technique is the only method employing currently available technology that can detect Earth-mass planets at high signal-to-noise, and can measure the frequency of terrestrial planets as a function of Galactic position. GEST's sensitivity extends down to the mass of Mars, and it can detect hundreds of terrestrial planets with semi-major axes ranging from 0.7 AU to infinity. GEST will be the first truly comprehensive survey of the Galaxy for planets like those in our own Solar System.

International Nuclear Information System (INIS)

Phase transformations from #alpha#- to #beta#-SiAlONs (i.e., from #alpha#' to #beta#') have been recently reported in a number of rare-earth SiAlON systems during postsintering heat treatment. In the present work, this transformation process in a Sm (#alpha# + #beta#)-SiAlON material is studied by using XRD, TEM, and EDS X-ray mapping techniques. It is observed that in addition to the formation of #beta#' and M' phases, the #alpha#'-to-#beta#' transformation is accompanied by a significant increase in the amount of an AlN-polytypoid phase. The results suggest that some #alpha#' phases are thermodynamically unstable at temperatures lower than the material sintering temperature and will decompose when conditions allow. For the composition studied in this work, the #alpha#-SiAlON decomposition can be described in general as #alpha#' #-># #beta#' + M' + AlN polytypoid.

International Nuclear Information System (INIS)

For the reuse of a waste salt from an electrorefining process of a spent oxide fuel, a separation of rare earth elements by an oxidative precipitation in a LiCl-KCl molten salt was tested without using precipitate agents. From the results obtained from the thermochemical calculations by HSC Chemistry software, the most stable rare earth compounds in the oxygen-used rare earth chlorides system were oxychlorides (EuOCl, NdOCl, PrOCl) and oxides (CeO2, PrO2), which coincide well with results of the Gibbs free energy of the reaction. In this study, similar to the thermochemical results, regardless of the sparging time and molten salt temperature, oxychlorides and oxides were formed as a precipitant by a reaction with oxygen. The structure of the rare earth precipitates was divided into two shapes: small cubic (oxide) and large plate-like (tetragonal) structures. The conversion ...

Energy Technology Data Exchange (ETDEWEB)

When the foundations of the building are designed and worked, the prediction calculation of immediate settlement of the building exercised practically is to calculate assuming the earth is a linear elastic body, but the actual stress-strain relationship of the earth is nonlinear and rigidity of the earth becomes lower as strain (or stress) increases. Hence in order to grasp the actual settling behavior of the earth, it is necessary to elucidate the nonlinear relationship between stress and strain. In this article, a prediction method of building settlement is introduced which uses an analytical technique of the multi-layered earth by the linear elasticity theory and takes into consideration strain dependency of rigidity of the earth. Part of the conclusion is as follows which has been obtained by studying the settling behaviors observed in ...

Energy Technology Data Exchange (ETDEWEB)

When a bipolar HVDC transmission system is operating monopolar using the earth as a return path, it is often desired to divert the return current from the earth to the line from the unused pole. To do so requires either that the system be shut down temporarily or that a dc circuit breaker be used. This paper describes the development of such a new dc circuit breaker, and its application on the Pacific Intertie as a Metallic Return Transfer Breaker (MRTB).

Science.gov (United States)

Sep 9, 2009... a French Ariane rocket successfully launched a new Earth-observing satellite ... The payload is a pair of identical sensors known as "high-resolution ... the resulting image) are activated simultaneously by incoming radiation; ...

Energy Technology Data Exchange (ETDEWEB)

An oxidative precipitation reaction of rare-earth chlorides in a LiCl-KCl molten salt was successfully carried out by a lab-scale apparatus. The conversion efficiency of the used rare earth chlorides into the insoluble precipitates was increased with the sparging time and temperature and was affected on oxygen sparger type. In the conditions of 700 .deg. C molten salt temperature and above 540min sparging time, the final conversion efficiencies were over 99% for all the experimented rare-earth chlorides. The hydrodynamic characteristics of an oxygen-molten salt two phase flow system are very important for a co-oxidative precipitation of rare earth elements.

British Library Electronic Table of Contents (United Kingdom)

This study presents new software, called Google Earth-based Optimal HAulage RouTing System (GEOHARTS), to improve the functionality of Google Earth for optimal haulage routing of off-road dump trucks in construction and mining sites. A modified least-cost path algorithm, which is applicable to working areas with both paved and unpaved temporary roads and can consider the effects of terrain relief and curves along a route on the route planning, was proposed and utilized for the software development. GEOHARTS can determine optimal haulage routes between loaders and dumps that ensure the least travel time or fuel consumption of off-road dump trucks and can visualize the results using an embedded 3D render window of Google Earth. The application to the Pasir open-pit coal mine in Indonesia dem...

Energy Technology Data Exchange (ETDEWEB)

The object of this program was to design and build a self-contained system for remote monitoring of the atmosphere in mines. The system developed uses the mine pager phone line as the primary communication channel and also has the capability of using 208 Hz in the ELF band for wireless transmission through the earth. The depth for through-the-earth transmission is expected to be about 80 to 90 meters in high conductivity soil and is limited by the noise level in the ELF band-pass filters. The underground components of the TEM System are energized by mine power through a battery charger-storage battery power supply. In the event of mine power failure the battery capacity is more than sufficient for 1 week's operation with interrogations every 4 hours.

Science.gov (United States)

1. Contest rules The European Space Agency (ESA) is launching a public competition to find the most suitable names for its four Cluster II space weather satellites. The quartet, which are currently known as flight models 5, 6, 7 and 8, are scheduled for launch from Baikonur Space Centre in Kazakhstan in June and July 2000. Professor Roger Bonnet, ESA Director of Science Programme, announced the competition for the first time to the European Delegations on the occasion of the Science Programme Committee (SPC) meeting held in Paris on 21-22 February 2000. The competition is open to people of all the ESA member states (*). Each entry should include a set of FOUR names (places, people, or things from history, mythology, or fiction, but NOT living persons). Contestants should also describe in a few sentences why their chosen names would be appropriate for the four Cluster II satellites. The winners will be those which are considered most suitable and relevant for the Cluster II mission. ...

International Nuclear Information System (INIS)

The desire to study negative ion structure and negative ion-photon interactions has spurred the development of ion sources for use in research and industry. The many different types of negative ion sources available today differ in their characteristics and abilities to produce anions of various species. Thus the importance of choosing the correct type of negative ion source for a particular research or industrial application is clear. In this study, the results of an investigation on the production of beams composed of negatively-charged rare-earth ions from a cylindrical-cathode-geometry, cesium-sputter-type negative ion source are presented. Beams of atomic anions have been observed for most of the first-row rare-earth elements, with typical currents ranging from hundreds of picoamps to several nanoamps.

International Nuclear Information System (INIS)

This paper introduces examples of satellite imageries analysis and utilizations for safeguards activities. Recently, many kinds of satellite imageries are available in the world i.e., high-spatial resolution, multi- and hyper-spectral, multi-function, and multi-polarization radars. The problem is that how to obtain the required information from these digital images. The Japan Aerospace Exploration Agency (JAXA) has successfully launched the Advanced Land Observing Satellite (ALOS, the nickname is 'Daichi') on 24th January, 2006. The mission objectives are cartography, regional observation, disaster monitoring etc. ALOS has three instruments, PRISM, AVNIR-2, and PALSAR, to achieve these objectives. An overview of ALOS is provided. ALOS follows the Japanese Earth Resources Satellite- 1 (JERS-1) and the Advanced Earth Observing Satellite (ADEOS) and utilizes advanced ...

International Nuclear Information System (INIS)

We have begun the ExploreNEOs project in which we observe some 700 Near-Earth Objects (NEOs) at 3.6 and 4.5 ?m with the Spitzer Space Telescope in its Warm Spitzer mode. From these measurements and catalog optical photometry we derive albedos and diameters of the observed targets. The overall goal of our ExploreNEOs program is to study the history of near-Earth space by deriving the physical properties of a large number of NEOs. In this paper, we describe both the scientific and technical construction of our ExploreNEOs program. We present our observational, photometric, and thermal modeling techniques. We present results from the first 101 targets observed in this program. We find that the distribution of albedos in this first sample is quite broad, probably indicating a wide range of compositions within the NEO population. Many objects smaller than 1 km have ...

Science.gov (United States)

Wildlife Monitoring System Schematic .......................... 40 ...... sentinel species - healthy fish are placed in an environment of water (where they arc not .... The way ir! which data for the fnre mdor study groups will be gathered tor managciacilt ...... Earth Resources Aircraft Program (ERAP) Camera ...

Science.gov (United States)

Federated Search (openSearch) (C. Lynnes); Infusion Process (S. Olding) Metrics Planning & Reporting (R. Ramapriyan); Service & Event Casting (B. Wilson) ...

CERN Document Server

The bright star 55 Cancri is known to host five planets, including a transiting super-Earth. The interferometric study presented here yields directly determined values for 55 Cnc's stellar astrophyiscal parameters: $R=0.943 \\pm 0.010 R_{\\odot}$, $T_{\\rm EFF} = 5196 \\pm 24$ K. We use isochrone fitting to determine 55 Cnc's age to be 10.2 $\\pm$ 2.5 Gyr, implying a stellar mass of $0.905 \\pm 0.015 M_{\\odot}$. Our analysis of the location and extent of the system's habitable zone (0.67--1.32 AU) shows that planet f ($M \\sin i = 0.155 M_{Jupiter}$) spends the majority of the duration of its elliptical orbit in the circumstellar habitable zone, where, with moderate greenhouse heating, it could harbor liquid water. Finally, our direct value for 55 Cancri's stellar radius allows for a model-independent calculation of the physical diameter of the transiting super-Earth 55 Cnc e ($\\sim 2.05 \\pm 0.15 ...

Science.gov (United States)

We briefly reviewed and summarized the experimental study on {beta}-delayed proton decays published by our group over the last 8 years, namely the experimental observation of {beta}-delayed proton decays of nine new nuclides in the rare-earth region near the proton drip line and five nuclides in the mass 90 region with N{approx}Z by utilizing the p-{gamma} coincidence technique in combination with a He-jet tape transport system. In addition, important technical details of the experiments were provided. The experimental results were compared to the theoretical predictions of some nuclear models, resulting in the following conclusions. (1) The experimental half-lives for {sup 85}Mo, {sup 92}Rh, as well as the predicted 'waiting point' nuclei {sup 89}Ru and {sup 93}Pd were 5-10 times longer than the macroscopic-microscopic model predictions of Moeller et al. [At. Data Nucl. Data Tables 66,131(1997)]. These ...

International Nuclear Information System (INIS)

The experimental study on #beta#-delayed proton decays near the proton drip line published by our group over the last 8 years were reviewed and summarized briefly, including first observation of 9 precursors in the rare-earth region and new measurements of 5 nuclei in the mass-90 region near N-Z line with the aid of the 'p-#gamma#' coincidence in combination with a He-jet tape transport system. Systematically comparing the experimental data with the current nuclear-model predictions, following points were represented. (1) the experimental half-lives for "8"5Mo and "9"2Rh as well as the predicted 'waiting point' nuclei "8"9Ru and "9"3Pd are 5-10 times longer than the macroscopic-microscopic model predictions given by Moeller et al. It considerably influences the prediction of mass abundances of the nuclides produced in rp-process. (2) The current-model predictions are not consistent with the experimental spin-parity ...

Energy Technology Data Exchange (ETDEWEB)

A novel two-phase flow management process useful for active thermal power rejection in space is introduced. The process serves as a condenser in a Rankine cycle and is applicable for thermal energy management needs in low gravity environments. Benefit is derived from the ability to utilize the high specific energy transport capability of two-phase flow, while not requiring mass-intensive solutions nor complex control strategies to maintain design energy balance integrity. Initial design calculations for a hypothetical space vapor cycle demonstration experiment were done and a steady-state computer model of the novel condensing process was created and used to evaluate its potential to maintain the design energy balance of the experiment. The experiment (approximately 28 kg) was a supercritical organic thermal loop operating between 500 and 400 Kelvin at a mass flow of 1 grain per second; using R-113 as the working fluid and rejecting all of its generated thermal energy to space ...

International Nuclear Information System (INIS)

In order to improve the measuring efficiency, a 'proton-gamma' coincidence technique in combination with a He-jet tape transport system was proposed and employed to identify the #beta#-delayed proton precursors. The study of #beta#-delayed proton decays near the proton drip line by using the 'proton-gamma' coincidence technique over the last 5 years at the Institute of Modern Physics, Lanzhou, China, was summarized. New #beta#-delayed proton precursors "1"2"1Ce, "1"2"5Nd, "1"2"8Pm, "1"2"9Sm, "1"3"5Gd, "1"3"7Gd, "1"3"9Dy, "1"4"2Ho, and "1"4"9Yb in the rare-earth region along a speculated proton drip line were synthesized and identified for the first time. The #beta#-delayed proton decays of "8"1Zr, "8"5Mo, "8"9Ru, and "9"3Pd in T_z=1/2 series as well as "9"2Rh in T_z=1 series were observed.

Science.gov (United States)

The Gateway to Astronaut Photography of Earth hosts the best and most complete online collection of astronaut photographs of the Earth.

Energy Technology Data Exchange (ETDEWEB)

Hard X-ray/gamma-ray spectrometers aboard two interplanetary spacecraft, Ulysses and Pioneer Venus Orbiter (PVO), and two near-Earth spacecraft, Yohkoh and Compton Gamma Ray Observatory (GRO/BATSE), are currently in operation. A unique set of circumstances have permitted the observation of the 15 November 1991 (2238 UT) flare by all the four instruments. This intense flare (GOES class X 1.5) was associated with the bright (3B) H-alpha flare located on the disk (S13, W19) in the active region 6919. At the time of the flare, the Ulysses and PVO spacecraft were located respectively 101[degree] and 52[degree] west of the Sun-Earth line. Thus the view angles for the PVO and Ulysses instruments were quite different from those of the near-Earth instruments on GRO and Yohkoh. The preliminary photon energy spectra observed by the four instruments at different times during the flare will be ...

International Nuclear Information System (INIS)

'Glass Earth' represents a number of current and planned projects within CSIRO aimed at making 'transparent' the top 1000 m of the Earth's crust It builds upon current technologies developed within a number of CSIRO divisions as well as the Australian Mineral Exploration Technologies CRC (AMET CRC), the Australian Geodynamics CRC (AG CRC) and the CRC for Landscape Evolution and Mineral Exploration (CRC LEME). New geophysical and geochemical technologies will be developed to complement these, together with new capabilities in modelling, data integration and visualisation, including hydrogeochemistry, hydrogeology, surface geochemistry and isotope geochemistry, modelling of chemical, fluid and heat flows in rock and regolith, advanced visualisation and data fusion. This paper describes some recent work in the field of isotope geochemistry, with the principal aim of 'seeing through' cover to understand basement geology and detect hidden ore ...

British Library Electronic Table of Contents (United Kingdom)

A new coumarin-based sensor molecule (L1) has been synthesized and this was found to bind calcium and magnesium ions more effectively as compared to other alkali/alkaline earth/lanthanide and certain transition metal ions. A significant enhancement in fluorescence intensity was observed on binding to Ca2+ and Mg2+ ions; while a minor quenching was observed for weakly bound Hg2+, Ni2+, Fe3+, and Co2+ ions. PET process, coupled with the ICT process, is proposed to explain the observed spectral response.

Science.gov (United States)

NASA's Visible Earth catalog of NASA images and animations of our home planet.

Energy Technology Data Exchange (ETDEWEB)

The effect of small misch metal additions (0.25 to 1 wt.%) on the corrosion behaviour of aluminium was studied through electrochemical polarization in 0.1 N inorganic and organic acids at room temperature. It has been observed that rare earth addition improves the corrosion resistance of aluminium. (orig.).

International Nuclear Information System (INIS)

Decay sequences based on the 1/2"+[660] proton orbital have been identified in "1"7"1Ta and "1"7"7Re based on spin, parity, and large alignment. This decay sequence is observed higher in energy than predicted in cranking calculations based on modified oscillator potentials. Similarly known 1/2"-[541] decay sequences in these and other neighbouring isotopes are observed lower in energy than predicted. A reduction in the strength of the spin-orbit potential for protons is suggested as a solution to these problem. (orig.).

Energy Technology Data Exchange (ETDEWEB)

The results of an investigation on the production of Group IIA atomic and molecular negative ion beams formed in a cesium-sputter negative ion source are presented. The sputtering material was formed by pressing pellets of stoichiometric mixtures of the Group IIA element carbonates and 10% copper powder. Negative ions of several alkaline-earth elements and their oxides have been observed. Beam intensities as high as 180 pA have been observed for Sr{sup -}and 20 nA for SrO{sup -}. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Decay sequences based on the 1/2/sup +/(660) proton orbital have been identified in /sup 171/Ta and /sup 177/Re based on spin, parity, and large alignment. This decay sequence is observed higher in energy than predicted in cranking calculations based on modified oscillator potentials. Similarly known 1/2/sup -/(541) decay sequences in these and other neighbouring isotopes are observed lower in energy than predicted. A reduction in the strength of the spin-orbit potential for protons is suggested as a solution to these problem.

CERN Document Server

We compare the metallicities of stars with radial velocity planets to the metallicity of a sample of field dwarfs. We confirm recent work indicating that the stars-with-planet sample as a whole is iron rich. However, the lowest mass stars tend to be iron poor, with several having [Fe/H]0.48) that contributes to but does not explain the mass-metallicity trend in the stars-with-planets sample. We use Monte Carlo models to show that adding an average of 6.5 Earth masses of iron to each star can explain both the mass-metallicity and the age-metallicity relations of the stars-with-planets sample. However, for at least one star, HD 38529, there is good evidence that the bulk metallicity is high. We conclude that the observed metallicities and metallicity trends are the result of the interaction of three effects; accretion of about 6 Earth masses of iron rich material, selection effects, and in some cases, high intrinsic ...

Energy Technology Data Exchange (ETDEWEB)

Many modern military systems used for communications, command and control, navigation, and surveillance depend on reliable and relatively noise-free transmission of radiowave signals through the earth`s ionosphere. Small-scale irregularities in the ionospheric density can cause severe distortion, known as radiowave scintillation, of both the amplitude and phase of these signals. The WBMOD computer program can he used to estimate these effects on a wide range of systems. The objective of this study is to investigate improvements to the WBMOD model based on extensive data sets covering both the equatorial and high-latitude regimes. This report summarizes the work completed during the third year of this project, which includes completion of the new model for the high-latitude (auroral and polar cap) region of the WBMOD model.

Science.gov (United States)

Automated Transport. Not Studied in Detail. Earth's Neighborhood. Simplified Infrastructure. Mars. Earth-. Moon L. 1. Gateway. Moon. Earth-Sun L. 2. Science ...

Energy Technology Data Exchange (ETDEWEB)

Recognizing that a high percentage of transmission-line faults are single-phase to earth and temporary in nature, provides the impetus for considering single-pole switching as a means to enhance the reliability of EHV transmission systems. The effectiveness of single-pole switching schemes is largely determined by the speed with which the secondary arcs extinguish, and hence allow system restoration. Simulation techniques that enable better prediction of the faulted-system response are of obvious importance to the design and assessment of the various single-pole switching scheme applications. In this thesis, digital methods are developed to enable the faulted response of EHV systems to be simulated for a variety of different single-pole switching schemes. These include conventional single-pole switching, the hybrid method of autoreclosure, the neutral switched reactor, and the High ...

Energy Technology Data Exchange (ETDEWEB)

The rare-earth based nickelates RNiO{sub 3} (R = Pr, Nd, Sm, Eu, and Pr{sub 1-x}La{sub x}, 0{<=}x{<=}0.7) were studied by inelastic neutron scattering. Energy splittings due to the crystalline-electric-field (CEF) interaction at the R{sup 3+} site within the electronic ground-state J multiplet (for R = Pr, Nd, and Pr{sub 1-x}La{sub x}) as well as within the two lowest-lying J multiplets (for R = Sm and Eu) were directly observed, and the corresponding CEF energy-level schemes were reconstructed. The latter were rationalized in terms of CEF parameters, which vary smoothly over the rare-earth series and give magnetic properties associated with the R sublattice in agreement with results from neutron powder diffraction experiments. Across the metal-insulator transition, a continuous change in the electronic part of the CEF parameters is observed. However, an attempt to quantify a charge ...

International Nuclear Information System (INIS)

The rare-earth based nickelates RNiO_3 (R=Pr, Nd, Sm, Eu, and Pr_1_-_xLa_x, 0#<=#x#<=#0.7) were studied by inelastic neutron scattering. Energy splittings due to the crystalline-electric-field (CEF) interaction at the R"3"+ site within the electronic ground-state J multiplet (for R=Pr, Nd, and Pr_1_-_xLa_x) as well as within the two lowest-lying J multiplets (for R=Sm and Eu) were directly observed, and the corresponding CEF energy-level schemes were reconstructed. The latter were rationalized in terms of CEF parameters, which vary smoothly over the rare-earth series and give magnetic properties associated with the R sublattice in agreement with results from neutron powder diffraction experiments. Across the metal-insulator transition, a continuous change in the electronic part of the CEF parameters is observed. However, an attempt to quantify a charge transfer from the ...

Energy Technology Data Exchange (ETDEWEB)

Magnetic properties of polycrystalline samples of RPd/sub 2/Si compounds (R = Gd, Tb, Dy, Ho and Er) are presented. The Gd and Tb based compounds are antiferromagnetic with Neel temperatures of 13.5 and 21 K respectively. For both compounds a metamagnetic transition is observed in low field. Moreover, in TbPd/sub 2/Si a transition between two different antiferromagnetic phases is observed at 8.5 K. The Dy, Ho and Er based compounds are ferromagnetic with Curie temperatures of 9, 3.5 ad 2.8 K respectively. The observed properties result from indirect exchange interactions and crystal field effects acting on rare earth ions which lie in a very low symmetry site.

Wastenet

... Electro-Osmotic Pulse (EOP) technology forces moisture to flow through concrete surfaces against the hydraulic gradient when an electric field is applied to an embedded anode system. This flow is initiated by the movement of cations (positively charged ions) present in a porous medium such as concrete toward the negative earth. Water surrounding the cations moves with them. The Corps of Engineers owns and maintains many buried ...

Energy Technology Data Exchange (ETDEWEB)

This book presents topics on: Density of rocks and minerals, includes histograms of density ranges; elastic constants of minerals, elastic moduli, thermal properties; inelastic properties, strength and rheology for rocks and minerals, rock mechanics and friction, and stress-strain relations; radioactivity, decay constants and heat production of isotope systems in geology; seismic attenuation, in rocks, minerals, and the earth, with application to oil exploration and terrestrial studies; and index.

Energy Technology Data Exchange (ETDEWEB)

This journal contains the following articles (1) The Grand Challenge of Thermonuclear Ignition--Commentary by Edward I. Moses; (2) Orchestrating the World's Most Powerful Laser--The computer control system for the National Ignition Facility will soon have about 1.4-million lines of code running on more than 750 computers; (3) A Randon Walk through Time and Space--Albert einstein's 1905 papers on Brownian motion, random fluctuations, and statistical mechanics are fundamental to many Livermore research projects; (4) The Search for Methane in Earth's Mantle--Scientists are discovering that Earth's mantle may have untapped reserves of methane; and (5) Testing the Physics of Nuclear Isomers--Results from a tri-laboratory project contradict claims of accelerated release of energy from the nuclear isomer hafnium-178.

Science.gov (United States)

Feb 25, 2008 ... NASA's Visible Earth catalog of NASA images and animations of our home planet.

International Nuclear Information System (INIS)

Thermophotovoltaic (TPV) systems are attractive possibilities for direct thermal-to-electric energy conversion, but have typically required the use of black body radiators operating at high temperatures. Recent advances in both the understanding and performance of solid rare-earth oxide selective emitters make possible the use of TPV at temperatures as low as 1200K. Both selective emitter and filter system TPV systems are feasible. However, requirements on the filter system are severe in order to attain high efficiency. A thin-film of a rare-earth oxide is one method for producing an efficient, rugged selective emitter. An efficiency of 0.14 and power density of 9.2 W/KG at 1200K is calculated for a hypothetical thin-film neodymia (Nd2O3) selective emitter TPV system that uses radioisotope decay as the thermal energy source.

DEFF Research Database (Denmark)

The tidal motion of the ocean water through the ambient magnetic field, generates secondary electric field. This motionally induced electric field can be detected in the sea or inland and has a potential for electrical soundings of the Earth. A first goal of the paper is to gain an understanding of the global distribution of the electric signal due to tidal ocean flow. We simulate the electric signals for two tidal constituents - lunar semidiurnal (M2) and diurnal (O1) tides. We assume a realistic Earth's conductivity model with a surface thin shell and 1-D mantle underneath. Simulations demonstrate that in some coastal regions the amplitudes of the electric field can reach 100 mV/km and 10 mV/km for M2 and O1 tides respectively. The changes of lithosphere resistance produce detectable changes in the tidal electric signals. We show that our predictions are in a good agreement with observations.

Energy Technology Data Exchange (ETDEWEB)

In many parts of the United States, as well as other regions of the world, competing demands for fresh water or water suitable for desalination are outstripping sustainable supplies. In these areas, new water supplies are necessary to sustain economic development and agricultural uses, as well as support expanding populations, particularly in the Southwestern United States. Increasing the supply of water will more than likely come through desalinization of water reservoirs that are not suitable for present use. Surface-deployed seismic and electromagnetic (EM) methods have the potential for addressing these critical issues within large volumes of an aquifer at a lower cost than drilling and sampling. However, for detailed analysis of the water quality, some sampling utilizing boreholes would be required with geophysical methods being employed to extrapolate these sampled results to non-sampled regions of the aquifer. The research in this report addresses using seismic and EM methods in ...

Energy Technology Data Exchange (ETDEWEB)

This project employs multi-disciplinary teams to accelerate development of the Community Climate System Model (CCSM), based at the National Center for Atmospheric Research (NCAR). A consortium of eight Department of Energy (DOE) National Laboratories collaborate with NCAR and the NASA Global Modeling and Assimilation Office (GMAO). The laboratories are Argonne (ANL), Brookhaven (BNL) Los Alamos (LANL), Lawrence Berkeley (LBNL), Lawrence Livermore (LLNL), Oak Ridge (ORNL), Pacific Northwest (PNNL) and Sandia (SNL). The work plan focuses on scalablity for petascale computation and extensibility to a more comprehensive earth system model. Our stated goal is to support the DOE mission in climate change research by helping ... To determine the range of possible climate changes over the 21st century and beyond through simulations using a more accurate climate system model that includes the full range of human ...

Energy Technology Data Exchange (ETDEWEB)

The performance of a high temperature ion source coupled to a helium gas-jet transport system for an efficient mass separation of neutron-rich alkaline earth and lanthanide isotopes is reported and the results of overall efficiency measurements using different cluster materials in the gas-jet are given. A fast, microprocessor controlled tape transport system for ..gamma..-spectroscopic studies on short-lived isotopes is described. Some results on the decay of 3.8sub(-s) /sup 152/Pr are presented.

Energy Technology Data Exchange (ETDEWEB)

The Fast On-Orbit Recording of Transient Events (FORTE) satellite being built by Los Alamos National Laboratory (LANL) and Sandia National Laboratories (SNL) has as its most prominent feature a large deployable (11 m by 5 m) log periodic antenna to monitor emissions from electrical storms on the Earth. This paper describes the antenna and the design for the long elements and explains the dynamics of their deployment and the damping system employed. It also describes the unique paraffin-actuated reusable tie-down and release mechanism employed in the system.

CERN Document Server

A proposal is made to test Newton's inverse-square law using the perihelion shift of test masses (planets) in free fall within a spacecraft located at the Earth-Sun L2 point. Such an Artificial Planetary System In Space (APSIS) will operate in a drag-free environment with controlled experimental conditions and minimal interference from terrestrial sources of contamination. We demonstrate that such a space experiment can probe the presence of a "hidden" fifth dimension on the scale of a micron, if the perihelion shift of a "planet" can be measured to sub-arc-second accuracy. Some suggestions for spacecraft design are made.

Energy Technology Data Exchange (ETDEWEB)

A parachute system was designed and prototypes built to deploy a telemetry package behind an earth-penetrating weapon just before impact. The parachute was designed to slow the 10 lb. telemetry package and wire connecting it to the penetrator to 50 fps before impact occurred. The parachute system was designed to utilize a 1.3-ft-dia cross pilot parachute and a 10.8-ft-dia main parachute. A computer code normally used to model the deployment of suspension lines from a packed parachute system was modified to model the deployment of wire from the weapon forebody. Results of the design calculations are presented. Two flight tests of the WBS were conducted, but initiation of parachute deployment did not occur in either of the tests due to difficulties with other components. Thus, the trajectory calculations could not be verified with data. Draft drawings of the major components of the parachute ...

International Nuclear Information System (INIS)

We report de Haas--van Alphen measurements of the Fermi surface of lutetium at temperatures down to 0.3 K and in fields up to 150 kG in the (1010) and (1120) planes. Lutetium, having a filled 4f shell, serves as a nonmagnetic prototype of the structurally similar (hcp), trivalent, heavy rare-earth elements from Gd to Tm. The fact that no complete frequency branches were observed indicates that there are no closed pieces of the Fermi surface. We observed all but one orbit predicted by relativistic augmented-plane-wave calculations of Keeton and Loucks and by recent spin-orbit--linearized-augmented-plane-wave calculations of Tibbetts and Harmon. The data support a geometry similar to that of yttrium, and in good qualitative agreement with energy-band theory.

Science.gov (United States)

The present conference on U.S. space transportation systems development discusses opportunities for aerospace students in prospective military, civil, industrial, and scientific programs, current strategic conceptualization and program planning for future U.S. space transportation, the DOD space transportation plan, NASA space transportation plans, medium launch vehicle and commercial space launch services, the capabilities and availability of foreign launch vehicles, and the role of commercial space launch systems. Also discussed are available upper stage systems, future space transportation needs for space science and applications, the trajectory analysis of a low lift/drag-aeroassisted orbit transfer vehicle, possible replacements for the Space Shuttle, LEO to GEO with combined electric/beamed-microwave power from earth, the National Aerospace Plane, laser propulsion to earth ...

International Nuclear Information System (INIS)

The crystal structure of borophosphates ABPO_5 (A = alkaline earth or Pb) was resolved on a polycrystalline sample using the Rietveld method. The x-ray diffraction patterns data show that ABPO_5 crystallize in a centrosymmetric space group P3_121 and their structure is related to the borogermanates REBGeO_5 with a stillwellite-type structure. Pr"3"+ ion was used as a local structural probe to corroborate the structural resolution results. Absorption and fluorescence spectra of A_1_-_xPr_xBP_1_-_xGe_xO_5 (A alkaline earth or Pb; x = 0.05) have been investigated at different temperatures. At 9 K the 3"H_4#->#"3P_0 transition of trivalent praseodymium ion (4f"2 configuration) is observed as a single line. This indicates a unique crystallographic site for the rare earth ion in these compounds replacing the divalent cation. Energy level schemes were deduced from the low-temperature spectroscopic ...

Energy Technology Data Exchange (ETDEWEB)

Magnetic properties of single crystals of nonstoichiometric fluorides M[sub 1-x]R[sub x]F[sub 2+x] (M = Ca, Sr, Ba; R = Ce, Pr, Nd, Gd, Ho, Er, Tm, Yb; with 0.05 [le] x [le] 0.28) with the fluorite-type structure have been studied for the first time. The magnetic susceptibility was measured using a Faraday balance in the 15-300 K temperature range. The samples are paramagnetic following the Curie-Weiss law. The values of paramagnetic Curie temperatures and effective magnetic moments of rare-earth ions have been found. Deviations of the temperature dependence of magnetic susceptibility from the Curie-Weiss law are observed for some nonstoichiometric fluorides at temperatures ranging from 60 to 85 K. Possible reaons for these deviations are discussed. Measurements of magnetic susceptibility provide an effective technique for a rapid and accurate determination of the concentration of rare-earth ions in nonstoichiometric ...

International Nuclear Information System (INIS)

SX Holdings Limited intends to establish a rare earths plant at Port Pirie, South Australia. The proposal involves three stages of development, Stage 3 being to develop a monazite cracking plant and associated rare earths separation facility with the capacity to process up to 8,000 t/a of monazite-type ores. The proposed initial capacity is 4,000 t/a. This Draft Environmental Impact Statement relates to Stage 3 and is based on a monazite processing capacity of 8,000 t/a. The justification of the project is given in terms of use and the market for rare earths, the economic and environmental benefits of the proposal, the site selection process, site rehabilitation, and the consequences of not proceeding. A detailed description of the project is given, including the treatment process, site development and facilities, the supply of raw materials, product and waste handling, transport and storage, plant commissioning, operation ...

Energy Technology Data Exchange (ETDEWEB)

Three independent studies have been conducted for assessing the impact of rocket launches on the earth`s environment. These studies have addressed issues of acid rain in the troposphere, ozone depletion in the stratosphere, toxicity of chemical rocket exhaust products, and the potential impact on global warming from carbon dioxide emissions from rocket launches. Local, regional, and global impact assessments were examined and compared with both natural sources and anthropogenic sources of known atmospheric pollutants with the following conclusions: (1) Neither solid nor liquid rocket launches have a significant impact on the earth`s global environment, and there is no real significant difference between the two. (2) Regional and local atmospheric impacts are more significant than global impacts, but quickly return to normal background conditions within a few hours after launch. And (3) vastly increased space launch activities equivalent to 50 ...

Energy Technology Data Exchange (ETDEWEB)

The heating system of the `Centre integre de mecanique industrielle de la Chaudiere`, in Saint-Georges, Quebec, is based on a solar wall and a geothermal heat pump with a glycol/water mixture circulating in 44 wells that are 100 m deep. With installation costs below $25 per sq.m, more than 85 per cent of the heating needs of the 9500 sq.m centre were supplied by geothermal power. The geothermal heat pump is composed of a well field and two 211-kW cooling units, each equipped with four coiled compressors. In winter, heat is pumped from the earth and in summer, a heat exchanger with control valves allows to heat to be dumped back into the earth. The monitoring and simulation of the system proved its efficiency, considering the climatic conditions in Quebec. The annual consumption of geothermal heating is 0.146 GJ per sq.m, which is very low compared to the consumption of electric heating (0.286 GJ per ...

Energy Technology Data Exchange (ETDEWEB)

A preliminary design effort directed toward a low concentration ratio photovoltaic array system capable of delivering multihundred kilowatts (300 kW to 1000 kW range) in low earth orbit is described. The array system consists of two or more array modules each capable of delivering between 113 kW to 175 kW using silicon solar cells or gallium arsenide solar cells, respectively. The array module deployed area is 1320 square meters and consists of 4356 pyramidal concentrator elements. The module, when stowed in the Space Shuttle's payload bay, has a stowage volume of a cube with 3.24 meters on a side. The concentrator elements are sized for a geometric concentration ratio (GCR) of six with an aperture area of .25 sq. m. The structural analysis and design trades leading to the baseline design are discussed. It describes the configuration, as well as optical, thermal and electrical performance analyses that support the ...

Science.gov (United States)

... that defines hydrometeor categories for the duration of the simulation ... and to observe the movement of any particular system ... particle settling occurred ...

Science.gov (United States)

... Title : The Numerical Weather Prediction System at the Italian Air Force Weather Service: Impact of Non-Conventional Observations and Increased ...

International Nuclear Information System (INIS)

Sialons are phases in the Si-Al-O-N and M-Si-Al-O-N systems where M includes Li, Mg, Ca, Sc, Y and the rare earth elements. They are comparable in variety with the mineral silicates and are built up of one-, two-, and three-dimensional arrangements of (Si,Al)(O,N)/sub 4/ tetrahedra in the same way that the structural units of the silicates are SiO/sub 4/ tetrahedra. These new materials include N-containing ceramics, glasses and glass-ceramics that are being explored for their thermal, chemical and physical properties.

CERN Document Server

The open source Scala language is a Java--based dynamic scripting, functional programming language. Moreover, this highly scalable scripting language lends itself well to building Cloud--based/deliverable Software as a Service (SaaS) online applications. Written by Lift Scala web framework founder and lead Dave Pollak, Beginning Scala takes a down--to--earth approach to teaching Scala that leads you through simple examples that can be combined to build complex, scalable systems and applications. This book introduces you to the Scala programming language and then guides you through Scala constr

Energy Technology Data Exchange (ETDEWEB)

A solar energy collection and conversion system is disclosed in which a cassegrain mirror system is rotated about a diurnal axis, which axis is adjusted for seasonal variations in the incidence of the sun's rays on the earth's surface. A black body absorption cavity filled with translucent or transparent fluid material is used for direct absorption of the sun's rays. The incident solar energy is absorbed directly by the fluid medium. The fluid within the cavity may be maintained under extremely high pressures and temperatures in order to utilize this fluid as a heat storage medium. Such heat storage is facilitated by apparatus which permits a change in the volume of the reflective cavity in response to the temperature or pressure of the fluid within the cavity.

Energy Technology Data Exchange (ETDEWEB)

WELLOG is a system of programs developed at the Earth Science Laboratory to be used to digitize well logs and perform some analysis and plotting of the data. Multiple logs can be plotted side by side for correlation analysis and up to three logs can be plotted in a cross plot. Data entry and editing functions are also provided by the programs. This system of well log interpretation programs is presently operating on the University of Utah UNIVAC 1108 computer. Digitizing of well logs is accomplished by an old model CALMA (off-line) digitizer. Those parts of WELLOG that handle the digitized data tapes are extremely machine dependent. The parts of WELLOG that produce the plots and handle the data beyond the digitized data tape are more portable.

Science.gov (United States)

Feb 25, 2008 ... In the two Landsat scenes shown above, the pattern of deforestation can be clearly discerned. Deep green in these images shows lush ...

Science.gov (United States)

films and cylinders of rare earth doped yttrium aluminum garnets. ... We knew that yttrium aluminum garnet (YAG) could be doped with ...

Science.gov (United States)

... of this material is, however, outside the currently approved earth fill materials collection area ... fill material suitable for its intended use. The currently approved site contains material that is ...

Energy Technology Data Exchange (ETDEWEB)

X-ray irradiation-induced paramagnetic radicals in rare earth (Ln) ion-doped glaserite and Ln ion-doped langbeinite were studied by means of ESR technique, aiming at developing the highly sensitive sensor for an ESR dosimetry. The samples were prepared by two kinds of procedures as follows. In one process, the glaserite (K{sub 3}Na(SO{sub 4}){sub 2}) matrix or the langbeinite (K{sub 2}Mg{sub 2}(SO{sub 4}){sub 3}) matrix were synthesized by heating the mixture of K{sub 2}SO{sub 4} and Na{sub 2}SO{sub 4} or the mixture of K{sub 2}SO{sub 4} and MgSO{sub 4} at 1023 K for 1 hour in He flow. The matrices obtained were mixed well with a fixed amount of Ln{sub 2}(SO{sub 4}){sub 3} (Ln=La, Eu, Gd, Lu) powder and heated at 1023 K for 1 hour in He flow. In the other process, the homogeneous mixture of a fixed amount of K{sub 2}SO{sub 4}, Na{sub 2}SO{sub 4} and Ln{sub 2}(SO{sub 4}){sub 3} powders or a fixed amount of K{sub 2}SO{sub 4}, MgSO{sub 4} and Ln{sub 2}(S0{sub 4}){sub ...

Energy Technology Data Exchange (ETDEWEB)

The COBE data on cosmic background radiation (CBR) isotropy and spectrum are generally considered to be explicable only in the context of the Big Bang theory and to be confirmation of that theory. However, this data can also be explained by an alternative, non-Big Bang model which hypothesizes an intergalactic radio-absorbing and scattering medium. Dense, force-free magnetic filaments generated by quasars, active galactic nuclei and Herbig-Haro objects can remain stable in the intergalactic medium for many Gy. They will be opaque to radiation with wavelengths longer than 100--400 microns, and essentially transparent to shorter wavelengths. They are thus capable of thermalizing and isotropizing the cosmic background radiation, and of accounting for the observed decrease of radio luminosity of galaxies within increasing distance from earth. A simple, inhomogeneous model of such an absorbing medium can reproduce both the isotropy and spectrum of ...

International Nuclear Information System (INIS)

The ternary rare earth compound NdRh_4B_4 has been studied by means of critical field, low temperature heat capacity, and static magnetic susceptibility measurements. Features in the upper critical field and heat capacity data at 1.31 K and 0.89 K suggest the occurrence of long-range magnetic order in the superconducting state. The temperature dependence of the static magnetic susceptibility follows a Curie-Weiss law with an effective magnetic moment #mu#sub(eff) = 3.58 +- 0.05 #mu#sub(B) and a Curie-Weiss temperature thetasub(p) = -6.2 +- 1.0 K between 20 K and room temperature. However, magnetization vs. applied magnetic field isotherms suggest the development of a ferromagnetic component in the Nd"3"+ magnetization at low temperatures. (author).

British Library Electronic Table of Contents (United Kingdom)

The crystal structure of Ca2RuD6 has been determined by neutron powder diffraction: space group Fm3m, K2PtCl6 structure, as found for other hexahydride salts of group 8 metals with alkaline earth or lanthanide counter ions. No structural phase transition was observed between 340K and 50K. The deuterium nuclear quadrupole coupling constant, 54.7kHz, leads to an ionic character of the Ru-D bond of 76%. The known trends in the behaviour of A2MH6 salts are interpreted in terms of the ionization energies of the cation and the central metal atom.

British Library Electronic Table of Contents (United Kingdom)

Commercial rolled magnesium sheets of alloys AZ31 (Mg-3 mass%Al-1 mass%Zn) and ZE10 (Mg-1 mass% Zn-<1 mass% Rare Earths) in O-temper condition were used for blanking experiments near room temperature. A serrated fracture surface can be observed in case of AZ31 but not in case of ZE10. During the shearing process of the AZ31 sheet, many micro cracks parallel to the sheet plane are generated in the shearing zone. These micro cracks lead to the formation of loose particles during the shearing operation, which interfere with further processing of the part and incur additional costs by increasing the scrap rate. It is found that the strong basal texture of this alloy is an important reason for the generation of such serrated cracks. In this paper a new method of selective texture modification i...

CERN Document Server

The true nature of the progenitor to GRBs remains elusive; one characteristic that would constrain our understanding of the GRB mechanism considerably is gamma-ray polarimetry measurements of the initial burst flux. We present a method that interprets the prompt GRB flux as it Compton scatters off the Earth's atmosphere, based on detailed modelling of both the Earth's atmosphere and the orbiting detectors. The BATSE mission aboard the \\textit{CGRO} monitored the whole sky in the 20 keV - 1 MeV energy band continuously from April 1991 until June 2000. We present the BATSE Albedo Polarimetry System (BAPS), and show that GRB 930131 and GRB 960924 provide evidence of polarisation in their prompt flux that is consistent with degrees of polarisation of $\\Pi>35$% and $\\Pi>50$% respectively. While the evidence of polarisation is strong, the method is unable to strongly constrain the degree of polarisation beyond a ...

International Nuclear Information System (INIS)

Three classes of solar emanations, namely, photon radiation from solar flares, solar energetic particles, and inhomogeneities in the solar wind that drive magnetic storms, are examined, and their effects on humans and technological systems are discussed. Solar flares may disrupt radio communications in the HF and VLF ranges. Energetic particles pose a special hazard at low-earth orbit and above, where they can penetrate barriers such as spacesuits and aluminum and destroy cells and solid state electronics. Energetic solar particles also influence terrestrial radio waves propagating through polar regions. Magnetic storms may disturb the operation of navigation instruments, power lines and pipelines, and satellites; they give rise to ionospheric storms which affect radio communication at all latitudes. There is also a growing body of evidence that changes in the geomagnetic field affect biological systems. 3 refs.

CERN Document Server

This paper presents three non-linear asymptotic observers corresponding to three examples of engineering interest: a chemical reactor, a non-holonomic car, and an inertial navigation system. For each example, the design is based on physical symmetries. This motivates the theoretical development of invariant observers, i.e, symmetry-preserving observers. We consider an observer to consist in a copy of the system equation and a correction term, and we give a constructive method (based on the Cartan moving-frame method) to find all the symmetry-preserving correction terms. They rely on an invariant frame (a classical notion) and on an invariant output-error, a less standard notion precisely defined here. For each example, the convergence analysis relies also on symmetries consideration with a key use of invariant state-errors. For the non-holonomic car and the ...

Energy Technology Data Exchange (ETDEWEB)

The electrogeometric model cannot consider the influence of some parameters on the screening of the wire conductor of the H.V. lines. For analysing the influence of these parameters (the conductor potential, the influence of the distance from phase conductor to earth wire, the influence of the reducing factor of the striking earth distance, the earth slope, etc.), the Monte Carlo method is preferable. The influence of the earth slope on the screening effect of the wire conductor for different conditions is presented in this paper. (author)

CSIR Research Space (South Africa)

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Energy Technology Data Exchange (ETDEWEB)

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Energy Technology Data Exchange (ETDEWEB)

Holmium doped barium based hexaferrites BaFe{sub 12-2x}Ho{sub 2x}O{sub 19} with (x = 0.0-1.0) were synthesized by solid state reaction method. Structural and magnetic characterization of these ferrites provide significant information about their reactive physical properties. X-ray analysis reveals that in all samples M-type structure exist with few secondary phases. Scanning electron microscope revealed the grain size of the specimen. The results show that grain size decreases with the substitution degree of Holmium. Thus rare earth element Holmium Ho{sup 3+} acts as a grain growth inhibitor. The magnetic hysteresis loops show the variation in the values of magnetic parameters like saturation magnetization (M{sub s}), remanent magnetization (M{sub r}) and coercivity (H{sub c}) were observed by changing Ho{sup 3+} content in BaFe{sub 12-2x}Ho{sub 2x}O{sub 19} ferrites. Coercivity showed a maximum value of 2230 Oe for (x = 0.4) and then ...

Energy Technology Data Exchange (ETDEWEB)

An ASTER (advanced spaceborne thermal emission and reflection radiometer) is one of the image sensors. It is to be installed in an earth survey polar orbit platform satellite, EOS-AM1, which is to be launched in 1998, and it is going to start its operation. Data observed by the thermal infrared remote sensing of ASTER include the spectral emissivity, and the spectral emission reflectivity which is expressed by the function of temperature. It is required to overcome technical problems how to extract the spectral emissivity from the observed data. The spectral emissivity extracted from the remote sensing data by the MMD method, measured for samples collected in Cuprite area, Nevada, and/or measured at sampled points were compared to each other and discussed. The hemisphere spectral reflectivity, which is indirect spectral emissivity, agreed well with the direct spectral emissivity. Data suggesting the establishment of ...

International Nuclear Information System (INIS)

The umbrella magnetic structure of the terbium iron garnet (TbIG) has been studied using neutron diffraction experiments peformed in the 4.2 to 650 K temperature range which covers both the Neel temperature (Tsub(N) = 550 +- 10 K) and the compensation temperature (Tsub(comp) = 244 +- 2 K). When T > Tsub(N), the observed peak intensities originate from nuclear contribution only. When Tsub(comp) < T < Tsub(N), the results have been interpreted in the Neel theory of ferrimagnetism. Below Tsub(comp), three salient features have been observed: there appears superstructure lines forbiden by the cubic space group Ia3d, whereas the other superstructure peaks are found absent contrary to other heavy rare earth garnets; the strongest reflexion (110) vanishes near Tsub(comp). The magnetic modes associated to the rhombohedral symmetry space group R(-3)c have been calculated; the two inequivalent magnetic sites C_1 and C'_1 of ...

Science.gov (United States)

To fulfill the President s Vision for Space Exploration - successful human and robotic missions between the Earth and other solar system bodies in order to explore their atmospheres and surfaces - NASA must reduce trip time, cost, and vehicle weight so that payload and scientific experiment capabilities are maximized. As a collaboration among NASA Centers, this project will generate products that will enable greater fidelity in mission/vehicle design trade studies, support risk reduction for material selections, assist in optimization of vehicle weights, and provide the material and process templates for development of human-rated qualification and certification Thermal Protection System (TPS) plans. Missions performing aerocapture, aerobraking, or direct aeroentry rely on technologies that reduce vehicle weight by minimizing the need for propellant. These missions use the destination planet s atmosphere to slow the ...

British Library Electronic Table of Contents (United Kingdom)

The mounting evidence about human-induced environmental change, and about its expected detrimental effects on humans and their societies (IPCC, 2007; Reid et al., 2010; Rockstrom et al., 2009), has turned out to be exceedingly difficult to turn into political action to mitigate the change and adapt to its consequences. Economic self-interest creates friction between nation-states, within regional alliances like the EU, and across the divide between the developing and developed world. A significant factor is a vocal and well-funded group of climate skeptics, who question the credibility of mainstream earth system science, overemphasize the disagreements within the scientific community, argue for more research before any action is warranted, and in general create doubt to justify inaction or...

British Library Electronic Table of Contents (United Kingdom)

In this paper we provide a geochemical investigation on 34 groundwater samples in the Mt. Vulture volcanic aquifer representing one of the most important groundwater resources of the southern Italy pumped for drinking and irrigation supply. The present study includes the first data on the abundance and mobility of minor and trace elements and the thermodynamic considerations on water-rock interaction processes in order to evaluate the conditions of alkali basalt weathering by waters enriched in magma-derived CO2. The results highlight the occurrence of two hydrofacies: bicarbonate alkaline-earth and alkaline waters deriving from low-temperature leaching of volcanic rocks of Mt. Vulture, and bicarbonate-sulfate-alkaline waters (high-salinity waters) related to prolonged water circulation in...

British Library Electronic Table of Contents (United Kingdom)

Many important advances in the physics of strongly correlated electron systems have been driven by the development of new materials: for instance the filled skutterudites Formula Not Shown ( Formula Not Shown metal, alkaline earth, lanthanide, or actinide; Formula Not Shown , Ru, or Os; Formula Not Shown , As, or Sb), certain lanthanide and actinide intermetallic compounds such as Formula Not Shown and Formula Not Shown ( Formula Not Shown , Rh, or Ir), and layered oxypnictides and related materials. These types of complex multinary d- and f-electron compounds have proven to be a vast reservoir of novel strongly correlated electron ground states and phenomena. In these materials, the occurrence of such a wide range of ground states and phenomena arises from a delicate interplay between com...

International Nuclear Information System (INIS)

Recent advances in thin film solar photovoltaic converters (PV's) can furnish multimegawatt power levels during lunar daylight periods with only modest mass requirements. The extended duration of lunar night (ca. 354 hr) and the high specific mass of earth-imported energy storage systems (regenerative fuel cells, batteries, etc.) render PV plus import storage power systems non-competitive with nuclear power plants for lunar bases. However, power storage or generation methods which can be constructed using primarily lunar materials, used either alone or with lightweight PV's, can be attractive alternatives to nuclear power. Three separate generic systems which can provide favorable low import mass goals have been identified and studied. These are: gravitational energy generation using lunar soil, thermal energy storage using basalt rock or glass, and electrochemical storage using lunar derived electrodes ...

Energy Technology Data Exchange (ETDEWEB)

A study of the joint evolution of the normal- and neutron-star components of massive binaries opens with a classification scheme and the analytic expressions to be applied in Paper II for computer simulation of the observable properties of such systems.

UK PubMed Central (United Kingdom)

An estimator for the load share parameters in an equal load-share model is derived based on observing k-component parallel systems of identical components that have a continuous...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The crystal structure and the luminescence properties of a new carbonate, Na{sub 3}Eu(CO{sub 3}){sub 3}, are presented. Na{sub 3}Eu(CO{sub 3}){sub 3} is orthorhombic, acentric, Ama2, Z = 4; a = 9.942(2) {angstrom}, b = 11.024(3) {angstrom}, c = 7.147(2) {angstrom}; R = 0.019, R{sub w} = 0.051, 2374 unique reflections. The anionic subnetwork is built up from the stacking of {open_quotes}standing on edge{close_quotes} and {open_quotes}flat lying{close_quotes} carbonate layers into which Na{sup +} and Eu{sup 3+} ions are inserted. The symmetry of the EuO{sub 9} polyhedra is C{sub s}. The Eu{sup 3+} ions are inserted. The symmetry of the EuO{sub 9} polyhedra is C{sub s}. The Eu{sup 3+} luminescence technique confirms the presence of a unique low symmetry site for the rare earth atom. The electrostatic crystal field (cf) effects on the {sup 7}F multiplet are evaluated on the basis of the phenomenological cf theory. The simulation using C{sub 2v} symmetry for the rare ...

International Nuclear Information System (INIS)

Pale colored BiY_1_-_xR_xGeO_5 (R=rare-earth from Pr to Yb) polycrystalline samples exhibit a crystalline phase isostructural with the orthorhombic Pbca (No. 61) structure-type established for BiYGeO_5 and BiYbGeO_5. R occupies a single point site in the host, with the lowest C_1 symmetry. While for Pr and Nd x must be #<=#0.35, for smaller R ions, Sm to Yb, the phase appears for any x content. Detailed crystallographic data for BiErGeO_5 have been determined from the structure refinement of its neutron diffraction profile at room temperature. Optical absorption and photoluminescence measurements at 10 K have been performed for BiEuGeO_5. An initial approach to the parametrization of crystal-field effects on this new host has been provided by results of the semi-empirical Simple Overlap Model, which considers the crystallographic positions of the nearest neighbors around R. Furthermore, the strongly reduced "7F_J_M set of levels of the 4f"6 configuration has ...

Energy Technology Data Exchange (ETDEWEB)

The Office of Civilian Radioactive Waste-Management in the Department of Energy (DOE) is responsible for disposing of this nation`s spent fuel and high-level radioactive waste in a manner that protects the health and safety of the public and the quality of the environment. Although embodied in the Federal repository program that began with studies in the late 1950s, this mission was explicitly established by the Nuclear Waste Policy Act of 1982 and reaffirmed by the Nuclear Waste Policy Amendments Act of 1987. To fulfill our mission, we are developing a waste management system consisting of a geologic repository for permanent disposal deep beneath the surface of the earth, a facility for monitored retrievable storage, and a system for transporting the waste. This discussion draft was developed to help involve parties affected by or interested in the waste-management program in the formulation of the basic principles on ...

British Library Electronic Table of Contents (United Kingdom)

The estimation of numerical values of the mean distance of closest approach of ions, a, of alkaline-earth metal ion salts in aqueous solutions, determined from activity coefficients, as well as from different theoretical approaches, is presented and discussed.

Science.gov (United States)

This frequently-asked-questions feature provides answers about earthquakes, faults, plate tectonics, and earth structure. Maps and diagrams are provided with some answers, and links to additional information and to related topics are included.

Science.gov (United States)

The Infrared Camera (IRC) is one of the scientific focal plane instruments on board the ASTRO-F infrared astronomical satellite. The IRC is designed for wide field imaging and slit-less spectroscopic observations at near- and mid-infrared wavelengths. The IRC consists of three channels; NIR, MIR-S and MIR-L, each of which covers wavelengths of 2-5, 5-12 and 12-26 micron, respectively. All channels adopt compact refractive optical designs. Large format array detectors (a InSb 512 x 412 array and two Si:As IBC 256 x 256 arrays) are employed. Each channel has 10 x 10 arcminutes wide FOV with diffraction-limited angular resolution of 70cm aperture of the liquid helium cooled telescope at wavelengths over 5 micron. A 6-position filter wheel is placed at the aperture stop in each channel, and has three band-pass filters, two grisms/prisms and a mask for dark current measurements. The 5 sigma sensitivity of one pointed observation is estimated to be ...

International Nuclear Information System (INIS)

After presenting a general account of the observed global properties of single stars of low, intermediate, and high mass, together with their theoretical Hertzsprung-Russell diagram evolution, attention is given to the observed properties of various evolved close binaries and to an assessment of the value of comparisons between observation and crude theory in characterizing the physics of mass transfer within interacting binary systems. Detailed consideration is then undertaken of such topics as stellar evolution in globular clusters, interior star changes due to nucleosynthesis and mixing, asymptotic giant branch stars of intermediate mass, the response of white dwarfs in binary systems to mass accretion, and scenarios for binary star evolution tending toward close white dwarf pairs.

International Nuclear Information System (INIS)

... angular momentum cranking model even-even nuclei gadolinium 156 governor

Energy Technology Data Exchange (ETDEWEB)

This paper presents an analysis of the performance of a selective emitter using small particles of rare earth compounds stable at high temperatures in a low emittance inert gas stream. An expression for the spectral emissive power excluding radiation scattering was derived to include the radiation in the emission band, produced by electronic transitions of the rare earth ion, and the continuum radiation outside the emission band produced by the rare earth host. Preliminary results suggest that a selective emitter based on suspended rare earth oxide particles will have high efficiency and merits further experimental investigation. {copyright} {ital 1996 American Institute of Physics.}

British Library Electronic Table of Contents (United Kingdom)

The electrophysical characteristics of the electric cable?s transition into a state of a heterogenic polymer system due to a wire?s explosion were examined. Using cyclic heating-cooling of the composite, the changes in its topology were observed. The latter makes it possible to regulate the dielectric characteristics of the system.

International Nuclear Information System (INIS)

The rare earth antimonates RE_3Sb_5O_1_2 constitute an isostructural series, where the rare earth site symmetry is S_4. The spectroscopic properties of pure or doped compounds of this family are studied in order to derive their energy level schemes and to simulate them through the crystal field theory, by using the approximated D_2_d potential. The paramagnetic susceptibilities are calculated with the derived wavefunctions and compared to experiment.

CERN Document Server

We calculated the matter effect, including both the Earth and supernova, on the detection of neutrinos from type II supernovae at the proposed Daya Bay reactor neutrino experiment. It is found that apart from the dependence on the flip probability P_H inside the supernova and the mass hierarchy of neutrinos, the amount of the Earth matter effect depends on the direction of the incoming supernova neutrinos, and reaches the biggest value when the incident angle of neutrinos is around 93^\\circ. In the reaction channel \\bar{\

Energy Technology Data Exchange (ETDEWEB)

Laser desorption (LD) and thermal desorption (TD) mass spectra of the metallofullerenes found in arc-produced primary soots have been studied for a large variety of alkaline earth and lanthanide elements. The metallofullerene ratios found in the LD spectra indicate that two distinct groups are observed: Sc, Y, La, Ce, Pr, Nd, Gd, Tb, Ho, Er, and Lu (group A) and Ca, Sr, Sm, Eu, and Yb (group B). The TD spectra of most of these same soots also separate into two groups that contain the same elements as groups A and B. Group A metallofullerenes show strong signals in both LD and TD spectra. Group B metallofullerenes are distinguished by their presence in the LD spectra but absence in the TD spectra. From the general ionic behavior of the elements of these groups, and recent studies of the endohedral oxidation states, we propose that the oxidation states are +3 for group A and +2 for group B. C[sub 70] metallofullerenes are anomalous in that they ...

CERN Document Server

We explore as clearly as possible the features of neutrino oscillation which are relevant for measurements of the CP violating Kobayashi-Maskawa phase delta and the sign of \\Delta m^2_{13}. We focus on the so called low-energy option and discuss principles for optimizing experimental parameters to measure these two quantities simultaneously. Toward the goal, we first formulate a method for obtaining a bird-eye view of the phenomenon of neutrino oscillation by introducing a new powerful tool called the ``CP trajectory diagram in bi-probability space''. It allows us to represent pictorially the three effects separately in a single diagram; effect from genuine CP violation due to the sin delta term, effect from the CP conserving cos delta term, and the fake CP violating effect due to earth matter. By using the CP trajectory diagram we observe that there is a two-fold ambiguity in the determination of delta which is related with the sign of Delta ...

International Nuclear Information System (INIS)

SiAlONs are ceramics with high potential as biomaterials due to their chemical stability, associated with suitable mechanical properties, such as high fracture toughness and fracture resistance. The objective of this work was to investigate the mechanical properties and the cytotoxicity of these ceramic materials. Three different compositions were prepared, using silicon nitride, aluminum nitride and a rare earth oxide mixture as starting powders, yielding Si_3N_4-SiAlON composites or pure SiAlON ceramics, after hot-pressing at 1750 deg. C, for 30 min. The sintered samples were characterized by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). Furthermore, hardness and fracture toughness were determined using the Vicker's indentation method. The biological compatibility was evaluated by in vitro cytotoxicity tests. Ceramic with elevated hardness, ranging between 17 and 21 GPa, and high fracture toughness of 5 to 6 MPa m"1"/"2 were obtained. ...

British Library Electronic Table of Contents (United Kingdom)

The Formula Not Shown system of Formula Not Shown was first observed in auroral emissions by Meinel in 1950. Although the Formula Not Shown band system has been reinvestigated since this first spectral study, no laboratory spectrum of the (2,1) vibronic band has been obtained. We have recently built a continuous-wave cavity ringdown spectrometer, and as a first test of this spectrometer we observed the (2,1) band of Formula Not Shown in a positive column discharge cell. Many lines of the first positive band system of Formula Not Shown were also identified during the process of assigning this spectrum. The relative intensities of the Formula Not Shown and Formula Not Shown bands were found to change with discharge cell pressure, and so each spectral region was observed at two pressures to a...

Science.gov (United States)

WR 104 is the prototype for a small but growing group of stars that present the remarkably striking appearance of pinwheels. High resolution images of WR 104 show the (apparently) face-on spiral turning with an 8 month period. The pinwheel is assumed to be composed of dust produced via colliding winds in a low-inclination WR+OB binary. These assumptions have been very successful in modeling the imaging, but remain largely untested by spectroscopy. Strong motivation for further study of this system has emerged. Recent theory suggests that some gamma-ray bursts (GRB's) are core-collapse supernovae viewed nearly pole-on. The WC class Wolf-Rayet star in WR 104 is the type of star thought to be a possible GRB progenitor. If the orbit (and thus stellar rotation axes) are pole-on, the effects on Earth's biosphere could be significant. Confrontation of the face-on colliding-wind binary model with eight years of spectroscopy, offering full phase ...

International Nuclear Information System (INIS)

Many important advances in the physics of strongly correlated electron systems have been driven by the development of new materials: for instance the filled skutterudites MT4X12 (M=alkali metal, alkaline earth, lanthanide, or actinide; T=Fe, Ru, or Os; X=P, As, or Sb), certain lanthanide and actinide intermetallic compounds such as URu2-xRexSi2 and CeTIn5 (T=Co, Rh, or Ir), and layered oxypnictides and related materials. These types of complex multinary d- and f-electron compounds have proven to be a vast reservoir of novel strongly correlated electron ground states and phenomena. In these materials, the occurrence of such a wide range of ground states and phenomena arises from a delicate interplay between competing interactions that can be tuned by partial or complete substitution of one element for another, as well as the application of pressure, and magnetic fields, resulting in rich and complex electronic phase diagrams in the hyperspace of ...

International Nuclear Information System (INIS)

Geothermal energy resources are found in many countries. A reasonable and efficient utilization of these resources has been a worldwide concern. The application of geothermal heat pump systems (GHPS) can help increase the efficiency of using geothermal energy and reduce the thermal pollution to the earth surface. However, this is only possible with a proper working fluid. In this paper, a non-azeotropic working fluid (R290/R600a/R123) is presented for a GHPS where geothermal water at 40-45 deg. C and heating network water at 70-80 deg. C serve as the low and high temperature heat sources. Experimental results show that the coefficient of performance (COP) of a GHPS using the working fluid is above 3.5 with the condensation temperature above 80 deg. C and the condensation pressure below 18 bar, while the temperature of the geothermal water is reduced from 40-46 deg. C to 31-36 deg. C.

International Nuclear Information System (INIS)

The extraction of rare earth elements, yttrium and aluminium from red mud resulting from alumina production with the ion-exchange resin KU-2-8n was studied. Experimental results are presented. The technology of hydrometallurgical processing of pulps obtained by sorption extraction of scandium from red mud is developed. It is shown that in the process of precipitation from sulfate sulfuric acid desorbate it became possible to obtain a high degree of rare earths deposition. The use of sodium hydroxide makes it possible to obtain a maximum deposition of rare earths and aluminium - 99.9 %. Aluminium leaching from crude composite concentrate gives a possibility to get concentrates which 15 - 20 times richer in yttrium and rare earths

CERN Document Server

Most of the presently identified exoplanets have masses similar to that of Jupiter and therefore are assumed to be gaseous objects. With the ever-increasing interest in discovering lower-mass planets, several of the so-called super-Earths (i.e., with masses in the interval 1 M_earth < M < 10 M_earth), which are predicted to be rocky, have already been found. Here we report the possible discovery of a planet around the M-type star GJ 436 with a minimum mass of 4.8+/-0.6 M_earth and a true mass of ~5 M_earth, which makes it the least massive planet around a main-sequence star found to date. In contrast with other discoveries, the planet is identified from its perturbations on an inner Neptune-mass transiting planet (GJ 436b), by pumping eccentricity and producing secular variations in the orbital inclination. Analysis of published radial velocity measurements indeed reveals a ...

Energy Technology Data Exchange (ETDEWEB)

In this paper, the adaptive optics (AO) system at Keck Observatory is characterized. The AO system is described in detail. The physical parameters of the lenslets, CCD and deformable mirror, the calibration procedures and the signal processing algorithms are explained. Results of sky performance tests are presented: the AO system is shown to deliver images with an average Strehl ratio of up to 0.37 at 1.59 {micro}m using a bright guide star. An error budget that is consistent with the observed image quality is presented.

DEFF Research Database (Denmark)

X-ray observations of the RSCVn system sigma Geminorum have been undertaken with the ROSAT observatory. Several spectra of very good signal-to-noise ratio were obtained. Spectral fitting using metal abundances amounting to 50% of solar values reveal two temperature components at 2 MK and 12 MK. Previous EXOSAT observations showed another component at 40 MK. Particular interest is focused on the temporal variations of the X-ray emission. It is found that variations occur on time scales ranging from years to hours and minutes.

Energy Technology Data Exchange (ETDEWEB)

A focused ion beam (FIB) system has been applied to prepare a thin foil specimen of Si, MgO and alumina which contained cracks in the plan of foil. It was possible to observe a much larger area at and near a crack tip than has been hitherto possible. FIB was also applied to observation of microstructure near a crack tip evolved during severe rolling contact fatigue in a steel.

UK PubMed Central (United Kingdom)

BackgroundThe successful use of zirconia ceramics in orthopedic surgery led to a demand for dental zirconium-based implant systems. Because of its excellent biomechanical characteristics,...Full Text Available

Science.gov (United States)

These steps are based on work done by the AIAA. Space-Based Observation Systems Committee on Standards (SBOS COS) as well as work done in this ..... Surface Weapons Center, Code B-10, Dahlgren, VA, 22448. Although it had many ...

Energy Technology Data Exchange (ETDEWEB)

Observational work on quasars, galaxies, and stars is summarized. Theoretical studies covering stars and stellar evolution, galaxies, clusters and cosmology, high energy astrophysics the solar system and the Sun are described. (ESA)

Energy Technology Data Exchange (ETDEWEB)

This document gathers the available presentations (articles and transparencies) given at this annual meeting, the 2007 topic of which was the technological, geopolitical, economical, environmental, societal and development stakes of energy. 1 - technological stakes - which energies for the future: new energies, illusion or solution of the future; the Lorraine region, an energy land: strategies and stakes for a sustainable development; from China to Brazil: understanding the nuclear energy revival; hydroelectric power: renewable and sustainable energy; renewable energies and environment protection: the contribution of biofuels; wind power in Germany between success and contestation; 2 - geopolitical stakes - energy levier of power: the Gulf of Guinea hydrocarbons: between development and geopolitics; the complex evaluation of resources and reserves between technology, market and geopolitics; the new Bakou-Tbilissi-Ceyhan pipeline: what impacts for Turkey and the European Union; 3 - ...

CERN Document Server

Simulations of planetary microlensing at high magnification that were carried out on a cluster computer are presented. It was found that the perturbations due to two-thirds of all planets occur in the time interval [-0.5t_FWHM, 0.5t_ FWHM] with respect to the peak of the microlensing light curve, where t_FWHM is typically about 14 hours. This implies that only this restricted portion of the light curve need be intensively monitored for planets, a very significant practical advantage. Nearly all planetary detections in high magnification events will not involve caustic crossings. The position angle, mass and projected orbital radius of a planet may be systematically determined from the planetary deviation. Earth mass planets may be detected with 1-m class telescopes if their projected orbital radii lie within about 1.5 - 2.5 AU. Giant planets are detectable over a much larger region. For multi-planet systems the perturbations due to individual ...

DEFF Research Database (Denmark)

The live outdoor webcam seems inseparable from the mid-1990s' popular proliferation of the Internet. Combining a well-known medium, i.e. the photograph, with a new one, i.e. the Internet, the live outdoor webcam seems in the rear-view mirror to have contributed significantly to the popular perception of the Internet as a globally distended and thus "geographical" medium. Moreover, due to its role in the NASA Triana mission, the never-realised flagship of the Clinton-Gore administration's Digital Earth project, the live webcam seemed to play an important part in the construction of what leading geographers coined a "virtual geography"-the geography of the Internet, and the networked geography-that sought to establish itself as a new field of study during the late 1990s. In order to substantiate for this interpretation, I would like in the first part of this article to identify a number of basic characteristics of the outdoor webcam and, in the second, to analyse and ...

International Nuclear Information System (INIS)

Power plant components exposed to environments such as water and soil are susceptible to severe corrosion. Many times the effect of corrosion in power plant components can be catastrophic. The problem is aggravated for underground pipelines due to additional factors such as large network of pipelines, proximity to earth mat, high voltage transmission lines, corrosive chemicals, inadequate approach etc. Other components such as condenser water boxes, internals of pipelines, clarifier bridge structures, cooling water inlet gates and pipes etc. which are in continuous contact with water, are subjected to severe corrosion. The nature and locations of all such components are at places which are not accessible for routine maintenance and hence they require long term reliable protection against corrosion. Experience has shown that anti-corrosive coatings are inadequate in preventing corrosion and due to their location regular maintenance coatings are also not feasible. ...

International Nuclear Information System (INIS)

This is the 1st revision of the INIS/ETDE Joint Thesaurus. It contains 20 953 valid descriptors and 8 600 forbidden terms. It was last updated in December 2003. The Joint Thesaurus contains the controlled terminology for indexing all information within the subject scope of both INIS (International Nuclear Information System) and ETDE (Energy Technology Data Exchange) information systems. The terminology is intended for use in subject description for input or retrieval of information in those systems. The thesaurus is a terminological control device used in translating from the natural language of documents, indexers or users into a more constrained system language It is also a controlled and dynamic vocabulary of semantically and generically related terms which covers a specific domain of knowledge. The domain of knowledge covered by this Thesaurus includes physics (in particular, plasma physics, atomic ...

CERN Document Server

We consider the effect of distributed delays in neural feedback systems. The avian optic tectum is reciprocally connected with the nucleus isthmi. Extracellular stimulation combined with intracellular recordings reveal a range of signal delays from 4 to 9 ms between isthmotectal elements. This observation together with prior mathematical analysis concerning the influence of a delay distribution on system dynamics raises the question whether a broad delay distribution can impact the dynamics of neural feedback loops. For a system of reciprocally connected model neurons, we found that distributed delays enhance system stability in the following sense. With increased distribution of delays, the system converges faster to a fixed point and converges slower toward a limit cycle. Further, the introduction of distributed delays leads to an increased range of the ...

CERN Document Server

An effective formalism for quantum constrained systems is presented which allows manageable derivations of solutions and observables, including a treatment of physical reality conditions without requiring full knowledge of the physical inner product. Instead of a state equation from a constraint operator, an infinite system of constraint functions on the quantum phase space of expectation values and moments of states is used. The examples of linear constraints as well as the free non-relativistic particle in parameterized form illustrate how standard problems of constrained systems can be dealt with in this framework.

Energy Technology Data Exchange (ETDEWEB)

Recently the real-time neutron radiography system of the Kyoto University Reactor (KUR) has been developed and practically applied to penetrating the side plates of the MTR type reactor fuels and investigation of moving objects. In this paper an application of the KUR neutron TV system to neutron computed tomography (NCT) is described. By using the NTV system, projection data can be acquired in a single measurement and simultaneously the projection image can be observed on a CRT monitor. The Fourier-convolution technique is used to produce the reconstructed image and its image has a good enough quality for revealing water in a small hole of 1.5 mm in diameter.

Energy Technology Data Exchange (ETDEWEB)

The rare earth antimonates RE{sub 3}Sb{sub 5}O{sub 12} constitute an isostructural series, where the rare earth site symmetry is S{sub 4}. The spectroscopic properties of pure or doped compounds of this family are studied in order to derive their energy level schemes and to simulate them through the crystal field theory, by using the approximated D{sub 2d} potential. The paramagnetic susceptibilities are calculated with the derived wavefunctions and compared to experiment.

British Library Electronic Table of Contents (United Kingdom)

Abstract The creation of chirality on Earth and the development of chiral life have been discussed in this highlight. Convincing evidence for the introduction of chirality on Earth is still fragmentary. We believe that by a combination of chiral crystallization and formation of helical polymers with preferred chiral conformational structure is the key to this question. This concept of macromolecular asymmetry has inspired ideas and resulted in possible rules for how chiral life as we know it, could have been introduced. These investigations needed the understanding of the requirements for chiral crystallization, for the stereochemistry of the initial formation of helical polymers, the measurements of optical activity of solids and their coordination with the fundamentals of chirality. Spac...

Energy Technology Data Exchange (ETDEWEB)

The general objective of this workshop is to investigate and discuss methods by which uncertainties in mass balance models for toxics in the Great Lakes may be reduced. As described by the workshop prospectus, this paper is focused on problems of reducing (and quantifying) uncertainty as they relate to in situ field observations/system response measurements for the establishment of initial conditions, boundary conditions, calibration/confirmation data sets, and model post-audit data sets.'' I have taken this description to refer not only to the evaluation of uncertainty in the field observations themselves, but also to the uncertainty associated the analyses of in situ observations as they interact in the overall modeling process. Thus, I will be concerned here with quantification and reduction of uncertainty both (1) as they may be applied to descriptions of the system that is being ...

Science.gov (United States)

The Asarco-Mission complex (image left) is an active producer of copper and molybdenum (important in making steel and other metal alloys), ...

Science.gov (United States)

... Astronomy & Space Biology Chemistry & Materials Computing Earth & Environment Education ... Materials Research Center at the University of Chicago, one of nearly 30 NSF-supported Materials ...

Science.gov (United States)

The rapidly growing field of remote sensing is beginning to supply massive amounts of high resolution imagery of the earth and other planets. ...

Science.gov (United States)

Feb 15, 2010 ... This astronaut photo from January 4, 2010, shows meander scars and oxbow lakes in the floodplain of the Rio Negro in South America.

Science.gov (United States)

Federal regulators were set to vote on a plan to protect deep water corals and other sensitive fish habitats that will likely include a permanent ban on ...

International Nuclear Information System (INIS)

English 2008 p. 132-133 Turkey Nishonov, Sh. Khujaev, S.

Science.gov (United States)

of Earth Science data and information management capabilities. Dale Schulz/400 . For your exceptional achievement in leading the joint LaRC/GSFC team in ...

Science.gov (United States)

The portion of the Waterpocket Fold illustrated in this image includes layered rocks formed during the Mesozoic Era (~ 250 65 million years ago) the oldest ...

Science.gov (United States)

goals for multisensor co-registration and fusion. 6 - 12.5 Km ..... Beta-Test toolkit for cyclogenesis and early evolution of cyclones ...

Science.gov (United States)

The SHARP cannon. Hydrogen is compressed in the tube on top, the gun barrel is on bottom. When Jules Verne wrote in 1865 "From Earth to the Moon" he ...

Energy Technology Data Exchange (ETDEWEB)

Extraction of rare earths (La, Ce, Pr, Eu, Gd, Er, Yb) from nitrate solutions by melts of carboxylic acids of the C/sub 17/-C/sub 20/ fraction and stearic acid with paraffin, depending on the temperature (60-90 deg), phase contact time and their volume ratio (O:B from 1:5 up to 1:100), pH of the aqueous phase (2-6), rare earth concentration (10/sup -6/-10/sup -3/ m) is studied. It is shown that in the whole concentration range investigated rare earths are extracted quantitatively into the carboxylic acid melt of C/sub 17/-C/sub 20/ fraction at the equilibrium value of pH>=3.8, while into the melt of 0.1 M stearic acid in paraffin at pH>=4.5.

Science.gov (United States)

Aug 23, 2011 ... Earthquakes, Hurricanes and Stubborn Instruments ... And if earthquakes and stubborn instruments aren't enough, there's this giant hurricane ...

Science.gov (United States)

May 11, 2007 ... "Deforestation in the tropics accounts for nearly 20 per cent of carbon emissions due to human activities," Dr. Canadell says. ...

Science.gov (United States)

Features: FOREST, DEFORESTATION, RIO JAMARI Geographic Region: BRAZIL .... Features: DEFORESTATION, TIERRAS BAJAS DEFORESTATION Geographic Region: BOLIVIA ...

Science.gov (United States)

Zinn, John;. Hoerlin,. Herman; and Petschek,. Albert. G.: The Motion of Bomb. Debris. Following the Starfish. Test. Radiation. Trapped in the Earth's ...

International Nuclear Information System (INIS)

The objectives of this research were to investigate the possibility of controlling the #alpha#'/#beta#' phase ratio and morphology in Sialon ceramics. These objectives have been sought by the control of the starting composition, and by post sintering heat treatment. The main emphasis has been on the production of a series of #alpha#' and (#alpha#'+#beta#') Sialon ceramics with a minimum amount of the glass phase by the pressureless sintering technique and using ytterbium (Yb) as an #alpha#' stabilising element. The Yb additions were made via the oxide or the alumino- silicate presynthesised glass; the latter was found to improve the density. The XRD analysis of the as sintered materials revealed #alpha#' to be the dominant phase with minor contributions from #beta#' sialon and/ or 12H A1N polytype. Additions of SiO_2 or #beta#-Si_3N_4 were made to various materials to assess potential mechanisms for obtaining control over the microstructural development of #alpha#'/#beta#' sialon ...

British Library Electronic Table of Contents (United Kingdom)

The type III secretion system among Gram-negative bacteria is known to deliver effectors into host cell to interfere with host cellular processes. The type III secretion system in Yersina, Pseudomonas and Enterohemorrhagic Escherichia coli have been well documented to be involved in the bacterial pathogenicity. The existence of type III secretion system has been demonstrated in neuropathogenic E. coli K1 strains. Here, it is observed that the deletion mutant of type III secretion system in E. coli strain EC10 exhibited defects in the invasion and intracellular survival in Acanthamoeba castellanii (a keratitis isolate) compared to its parent strain. Next, it was determined whether type III secretion system plays a role in E. coli K1 survival inside Acanthamoeba during the encystment process...

Energy Technology Data Exchange (ETDEWEB)

The use of global three-dimensional (3-D) models with satellite observations of CO2 in inverse modeling studies is an area of growing importance for understanding Earth s carbon cycle. Here we use the GEOS-Chem model (version 8-02-01) CO2 mode with multiple modifications in order to assess their impact on CO2 forward simulations. Modifications include CO2 surface emissions from shipping (0.19 PgC yr 1), 3-D spatially-distributed emissions from aviation (0.16 PgC yr 1), and 3-D chemical production of CO2 (1.05 PgC yr 1). Although CO2 chemical production from the oxidation of CO, CH4 and other carbon gases is recognized as an important contribution to global CO2, it is typically accounted for by conversion from its precursors at the surface rather than in the free troposphere. We base our model 3-D spatial distribution of CO2 chemical production on monthly-averaged loss rates of CO (a key precursor and intermediate in the oxidation of organic ...

International Nuclear Information System (INIS)

An analytic solution is obtained for the equations of resonance coherent SRS by neglecting the population of the final level of the Raman transition for the systems with the active-medium length that is smaller than the wavelength of the incident light. For the extended systems, a numerical solution is obtained. The energy distribution of the Stokes pulses is found. The large-scale (about 100%) fluctuations of the Stokes radiation energy were observed in the case of unsaturated amplified spontaneous emission. (nonlinear optical phenomena)

International Nuclear Information System (INIS)

To assess the diagnostic capability Fuji computed radiography (FCR) using a dual side reading system was compared to the conventional radiography using a film-screen system. Twenty-eight patients with lung cancer were examined with a new FCR system (FCR 5501D) and a conventional screen-film system concurrently. FCR utilizes a reading system that detects emissions from dual sides of imaging plate. Chest X-rays were obtained with same exposure factors in both systems. Image qualities of both systems were compared by two radiologists using a five-level score. There were no lesion that FCR images were inferior to film-screen images. The frequency of score +1 or +2 that FCR images were superior to film-screen images was 31% in large nodular shadows, 40% in accompanying shadows with a nodule, 67% of small nodular shadows, and 43% of the lymph node ...

Energy Technology Data Exchange (ETDEWEB)

Porosity evolution at reactive interfaces is a key process that governs the evolution and performances of many engineered systems that have important applications in earth and environmental sciences. This is the case, for example, at the interface between cement structures and clays in deep geological nuclear waste disposals. Although in a different transport regime, similar questions arise for permeable reactive barriers used for biogeochemical remediation in surface environments. The COMEDIE project aims at investigating the coupling between transport, hydrodynamics and chemistry when significant variations of porosity occur. The present work focuses on a numerical benchmark used as a design exercise for the future COMEDIE-2D experiment. The use of reactive transport simulation tools like Hytec and Crunch provides predictions of the physico-chemical evolutions that are expected during the future experiments in laboratory. Focus is given in ...

International Nuclear Information System (INIS)

A Real-Time Neutron Radiography (RTNR) system and a high speed X-ray Computed Tomography (X-CT) system are used to determine the flow regime, the instantaneous cross-sectional averaged void fraction, and the time averaged void fraction in a vertical annulus flow channel. A standard optical video system is also used to observe the flow regime. The annulus flow channel is operated as a bubble column and measurements are obtained for gas flow rates form 0.0 to 30.0 l/min. The flow regimes observed by all three measurement systems via image analysis shows that the results agree well with each other. Both the RTNR and the X-CT systems show that the time averaged and cross-sectional averaged void fraction increases with increasing superficial gas velocity. Time and cross-sectional averaged void fractions determined by the RTNR ...

International Nuclear Information System (INIS)

A Real-Time Neutron Radiography (RTNR) system and a high speed X-ray Computed tomography (X-CT) system are compared for measurement of two-phase flow. Each system is used to determine the flow regime, and the void fraction distribution in a vertical annulus flow channel. A standard optical video system is also used to observe the flow regime. The annulus flow channel is operated as a bubble column and measurements obtained for gas flow rates from 0.0 to 30.01/min. The flow regimes observed by all three measurement systems through image analysis shows that the two-dimensional void fraction distribution can be obtained. The X-CT system is shown to have a superior temporal resolution capable of resolving the void fraction distribution in an (r,#theta#) plane in 33.0 ms. Void fraction distribution for bubbly flow and slug ...

Energy Technology Data Exchange (ETDEWEB)

Aimed at post-graduate and post-doctoral researchers in geochemistry, this book reflects the rapid changes in the applications of radioactive and stable isotope analysis to a range of geological and geochemical problems. Isotropic chemistry and methods used in mass spectroscopy are discussed initially. The second section deals with radiometric dating methods. The role of isotopes in climate and environmental research is also explored. The book closes with a section on extra-terrestrial matter, geothermometry and the isotopic geochemistry of the Earth`s lithosphere. (UK).

Energy Technology Data Exchange (ETDEWEB)

Clays and zeolites are among the most important of natural dusts by virtue of their occurrence through out the world on the earth`s surface and their important industrial uses. (The 1:1 layer silicates, including the serpentine and kaolin minerals, are not addressed in this chapter.) This chapter provides basic information on a variety of important aspects of each mineral, including crystal structure diagrams of each and references to more detailed discussions. 110 refs., 20 figs.

Wastenet

...6 Resource type: reference data Global Change Master Directory An extensive source of information about satellite and in situ Earth science data, with broad coverage of the atmosphere, hydrosphere, oceans, solid earth, and biosphere. Author: NASA Subjects: climatology, global change, oceanographic data DeweyClass: 551.6 Resource type: documents, news International ...

International Nuclear Information System (INIS)

CIRNAT, a one-dimensional code for natural circulation analysis, was described. The homogeneous approach was adopted for the two-phase flow regime and different heat transfer regimes were considered. The code was exhaustively tested for one-phase flow systems. For two phase flows a boiling/condensing system was simulated. The results are qualitatively correct but the oscillations observed at the system were not captured by the model. Other two-phase flow tests must be done to show the limits of the homogeneous approach before the introduction of a more complex model. (author)

Energy Technology Data Exchange (ETDEWEB)

This paper reviews the molecular biology of the renin-angiotensin system. The renin gene structure is analyzed in detail, including an examination of the putative regulatory regions. The combined action of these regulatory sequences would result in the complex, tissue-specific expression and regulation observed in vivo. The expression of the tissue renin-angiotensin systems, which may have important physiological functions, is also described. In addition, the pathway of renin biosynthesis and secretion is reviewed. This includes speculation on the fate of circulating prorenin and the physiological role of multiple renin forms and secretory pathways. The molecular approaches described in this paper have greatly advanced our knowledge of the biology of the renin-angiotensin system. Future studies using these and other approaches should provide further insight into this complex system.

Energy Technology Data Exchange (ETDEWEB)

Neutron radiography is a non-destructive test method to examine a material by using the dependency of neutron attenuation on the nuclear characteristics of the atoms composing the object material. There are two categories of neutron radiography; static neutron radiography and dynamic neutron radiography. The static neutron radiography is a technique to observe a standing object by using a camera or a film cassette. The dynamic neutron radiography(DNR) is a technique to observe a moving object usually by using a camera. Depending on the camera frame rate, the dynamic neutron radiography is categorized into the real time neutron radiography(RTNR) and the high speed neutron radiography(HSNR). The frame rate for RTNR is 30 frames/s and that for HSNR is usually more that 500 frames/sec. Thus, RTNR is good for observing time-averaged phenomena and HSNR is good for observing instantaneous phenomena. DNR is a ...

Energy Technology Data Exchange (ETDEWEB)

The young open cluster Berkeley 87 was predicted to be associated with the COS B {gamma}-ray source 2CG 075+00 on the basis of the experimental evidence of the presence of a shock front around the Wolf - Rayet star ST3 placed in the inner part of the cluster. The CGRO phase-1 data confirm this identification. Protons accelerated at the shock boundary can produce {pi} deg. via p-p interactions and then {gamma}-rays. With the measured flux F{sub {gamma}} (E > 100 MeV) {approx_equal} 9x10{sup -7} ph cm{sup -2} s{sup -1} and the power-law proton spectrum with spectral index {gamma} = 2, the cosmic-ray-energy-density in the inner part ({approx} 0.8 pc radius) of Berk 87 is about 100 times greater than that in the vicinity of the Earth. We have calculated {gamma}-ray spectra expected from the decay of {pi}{sup d}eg. produced in p-p interactions. The spectra have been normalized to the observed flux of Berk 87 by using different input proton ...

Energy Technology Data Exchange (ETDEWEB)

The NA50 Collaboration has recently observed a strong suppression of {ital J}/{psi} production in Pb-Pb collisions at 158GeV/nucleon. We show that this recent observation finds a quantitative explanation in a model which relates the suppression mechanism to the local energy density, whose value is higher in Pb-Pb collisions than in any other system studied previously. The sensitivity of the phenomenon to small changes in the energy density could be suggestive of quark-gluon plasma formation. {copyright} {ital 1996 The American Physical Society.}

Energy Technology Data Exchange (ETDEWEB)

Magnetic fluctuations present in the paramagnetic Mn{sub 0.81}Ni{sub 0.19} system have been investigated by measuring inelastic magnetic neutron scattering from a single crystal at temperatures of 450, 585 and 700 K. Antiferromagnetic correlations are observed to be present at all the temperatures studied. The spectral width of the magnetic scattering has been observed to increase with temperature, while the spatial range of the magnetic correlations is seen to decrease as the temperature is raised. The wave-vector-dependent susceptibility is found to follow a Curie-Weiss law near the (1 0 0) position, in agreement with theoretical predictions.

International Nuclear Information System (INIS)

It is experimentally demonstrated that a relatively strong ion-rich sheath formed at a fixed negative bias of the grid can be changed to a rather weak ion sheath (sheath potential weakly retards electrons) only by increasing the discharge voltage in the system. At sufficiently high negative grid bias, an increase of discharge voltage enhances the ion collection current at the grid. An explanation is put forward in support of this experimental observation. A slight density enhancement with a fall in plasma electron temperature is also observed with the increasing negative grid bias. (authors)

Energy Technology Data Exchange (ETDEWEB)

In 2009, the Atmospheric Radiation Measurement (ARM) Program and the Climate Change Prediction Program (CCPP) have been asked to produce joint science metrics. For CCPP, the second quarter metrics are reported in Evaluation of Simulated Precipitation in CCSM3: Annual Cycle Performance Metrics at Watershed Scales. For ARM, the metrics will produce and make available new continuous time series of radiative fluxes based on one year of observations from Barrow, Alaska, during the International Polar Year and report on comparisons of observations with baseline simulations of the Community Climate System Model (CCSM).

Energy Technology Data Exchange (ETDEWEB)

We present a systematic study of the magnetization, Hall effect and specific heat on single crystals of Mn{sub 4}Si{sub 7}. Curie-Weiss law is observed above 43 K. At low-temperature moments order in an anisotropic helical state and are aligned above 1 T. We observe an anomalous Hall effect in both {rho}{sub H} vs. B and in R{sub H} vs. T curves and a field dependence of the low T specific heat due to spin fluctuations. The magnetic moments (p{sub eff} and p{sub sat}) are the lowest reported for similar itinerant magnetic systems, this suggests that Mn{sub 4}Si{sub 7} is a good candidate to observe critical quantum fluctuations expected for a marginal Fermi liquid.

Energy Technology Data Exchange (ETDEWEB)

The authors have studied (Al{sub x}Ga{sub 1{minus}x}){sub 0.5}In{sub 0.5}P doped with tellurium using deep level transient spectroscopy and associated electrical measurements. Several defect states are observed in the upper half of the band gap, that are believed to be intrinsic to the alloy system as well as related to the tellurium donors. Defects observed at measurement temperatures above 390 K exhibit a hysteretic behavior. The observed spectra depend on the biasing conditions applied to the Schottky diode during cooling. The hysteretic behavior suggests the existence of different defect configurations, which can be accessed under conditions of high temperatures and electrical stress, but remain stable below 300 K.

Energy Technology Data Exchange (ETDEWEB)

Modern high-resolution electron microscopy (HREM) instruments, which are capable of a point-to-point resolution of better than 0.2 nm, have allowed atomic-scale observations of a variety of internal interfaces. The application of the HREM technique to fcc model systems for the purpose of addressing a number of interface issues will be examined in this paper. Atomic structure observations for heterophase interfaces of metal/metal and metal/metal-oxide systems as well as HREM studies of grain boundaries in NiO and Au will be discussed with emphasis on generic structural features and the role of the interface plane. Comparisons between observed interface structures and atomistic computer modeling results have shown agreements for some interfaces, as well as certain differences in others. A number of structural features are common to both metal and oxide grain boundaries, as well as ...

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The neutron radiography system installed at the E-2 experimental hole of the KUR (Kyoto University Reactor) has been used for some NDT applications in the nuclear field. The on-line video image processing system of this facility is introduced in this paper. A 0.5 mm resolution in images was obtained by using a super high quality TV camera developed for X-radiography viewing a NE-426 neutron-sensitive scintillator. The image of the NE-426 on a CRT can be observed directly and visually, thus many test samples can be sequentially observed when necessary for industrial purposes. The video image signals from the TV camera are digitized, with a 33 ms delay, through a video A/D converter (ADC) and can be stored in the image buffer (32 KB DRAM) of a microcomputer (Z-80) system. The digitized pictures are taken with 16 levels of gray scale and resolved to 240 x 256 picture elements (pixels) ...

International Nuclear Information System (INIS)

The real-time neutron radiography system of the Kyoto University Reactor (KUR) has been practically applied to penetrating the side plates containing boron burnable poison to test MTR type reactor fuels and to investigation of moving objects. Compared with the image obtained by the direct film method, however, the image from the TV system is in low-contrast and poor-resolution. This paper presents some digital processing approaches to improve the image quality and the neutron TV system is successfully applied to neutron computed tomography (NCT). The frame summing technique is effective to increase the quality of the radiographic image. By using the NTV system in NCT, the projection data are able to be acquired in a single measurement as observing the projection image on a CRT monitor. Two weighting functions based on the Fourier-convolution algorithm are employed to obtain the ...

International Nuclear Information System (INIS)

Medical imaging using single gamma-ray-emitting radionuclides typically makes use of parallel hole collimators or pinholes in order to achieve good spatial resolution. However, a tradeoff in sensitivity is inherent in the use of a collimator, and modern preclinical single photon emission computed tomography (SPECT) systems detect a very small fraction of emitted gamma rays, often less than 0.1%. A system for small animal SPECT imaging which uses no collimators could potentially achieve very high sensitivity-several tens of percent-with reasonably sized detectors. This would allow two significant improvements in preclinical studies: images could be obtained more rapidly, allowing higher throughput for screening applications, or for dynamic processes to be observed with very good time resolution; and images could be obtained with less radioactive tracer, making possible the in vivo imaging of low-capacity receptor ...

International Nuclear Information System (INIS)

This study serves to investigate the uptake of POPs in the different trophic levels (scrapers, collectors, predators, shredders) of macroinvertebrate communities sampled from a glacial and a non-glacial stream in the Italian Alps. The presented results show that the contaminant concentrations in glacial communities are generally higher compared to those from non-glacial catchments, highlighting the importance of glaciers as temporary sinks of atmospherically transported pollutants. Moreover, the data also suggests that in mountain systems snow plays an important role in influencing macroinvertebrate contamination. The main chemical uptake process to the macroinvertebrates is considered to be bioconcentration from water, as similar contaminant profiles were observed between the different trophic levels. The role of biomagnification/bioaccumulation is thought to be absent or negligible. The enrichment of chemicals observed in ...

Energy Technology Data Exchange (ETDEWEB)

Reliable facility of cyclotron-based real time neutron radiography system has been developed and applied to some industrial components. The equipment for neutron fluoroscopy is based on a sub-compact cyclotron and a LiF/ZnS (Ag) fluorescent screen viewed by a silicon intensifier target TV camera. The real time image is monitored on a CRT, recorded with a standard video recorder and processed by a digital image processor. The effectiveness of our real time neutron radiograph has been demonstrated to be applicable to not only the dynamic observation but also the magnifying and stereoscopic observation of fluoroscopic images.

Energy Technology Data Exchange (ETDEWEB)

An adaptive contingency selection process is set up which produces outage lists in order to guarantee on-line network security control. The quality index system used so far did not detect and reveal all critical variables due to observation problems in the mapping of two functions. The new process uses the results of the outage simulation computing of the system status just past for the drawing up of an up-to-date outage list. A linear correcting function transform the G{sub 2}-values of the standard quality index method - which still incorporate the observation problem effect - into improved values G. Studies which use data from realstic high-voltage networks prove that the detection of critical variables is far superior to ordinary methods. (orig.).

CERN Document Server

System identification refers to estimation of process parameters and is a necessity in control theory. Physical systems usually have varying parameters. For such processes, accurate identification is particularly important. Online identification schemes are also needed for designing adaptive controllers. Real processes are usually of fractional order as opposed to the ideal integral order models. In this paper, we propose a simple and elegant scheme of estimating the parameters for such a fractional order process. A population of process models is generated and updated by particle swarm optimization (PSO) technique, the fitness function being the sum of squared deviations from the actual set of observations. Results show that the proposed scheme offers a high degree of accuracy even when the observations are corrupted to a significant degree. Additional schemes to improve the accuracy still further are ...

Energy Technology Data Exchange (ETDEWEB)

Multi-dimensional modelling of two-phase flow requires accurate constitutive relationships for interfacial parameters such as interfacial heat transfer, void fraction distribution, interfacial area, etc. However, existing diagnostic systems for measurement of two-phase flow parameters have difficulty measuring two or three-dimensional void distributions required for determination of interfacial parameters. In this work, a Real-Time Neutron Radiography (RTNR) system is developed for non-intrusive measurement of two-phase flow parameters in nuclear fuel channels at low thermal neutron fluxes (on the order of 10{sup 6}n/cm{sup 2}-s). This advanced radiation technique has the advantage of measuring two-phase flow in 3 1/2 dimensions (x,{integral}dy,t) where the 1/2 dimension refers to an integrated or averaged space dimension. Pipe flow channels, annulus flow channels, MAPLE-type nuclear fuel flow channels, and CANDU-type nuclear fuel flow channels ...

International Nuclear Information System (INIS)

The authors report on observations of plasma wave turbulence generated during electron beam injections, spacecraft potential variations, and neutral gas emissions of the CHARGE 2 sounding rocket experiment. The payload was flown in a mother/daughter configuration, with the two sub-payloads electrically connected by an insulated, conducting tether. While tethered, the two platforms were separated, drifting apart in a direction perpendicular to both the magnetic field and to the spacecraft velocity, reaching a maximum distance of 426 m at the end of the flight. The mother carried a high-voltage (HV) system (0-460 V), biasing the mother negative relative to the daughter. The operation of the HV bias system simulated the motional emf induced in larger orbiting space structures like the Tethered Satellite System 1 (TSS 1) space shuttle mission scheduled for the spring of 1992. In addition, the mother carried ...

Energy Technology Data Exchange (ETDEWEB)

Storage of thermal energy in aquifers has obvious benefits of saving energy and decreasing the consumption of fossil fuels. However, aquifer thermal energy storage (ATES), which involves groundwater aquifers as the storage medium for heat or chill, impinges on the environment. A literature review of pertinent microbiology publications (Hicks and Stewart, 1988) identified the potential for the interaction of ATES systems and microbiological processes to create a source of infectious diseases and the potential for damage to the environment. In addition, the review identified a potential for microbiological processes to develop conditions that would interfere with the operation of an ATES system. As a result of this research effort, investigators from Finland, Germany, Switzerland, and the United States have examined several ATES systems in operation and have observed that the ATES ...

International Nuclear Information System (INIS)

More than sixty base-isolated buildings have been built in Japan. A number of base-isolation systems were considered in our research, which was intended to establish the effectiveness of base-isolation systems. We conducted research on silicone rubber bearings. Generally, silicone rubber is durable and its characteristics are not dependent on the temperature within the relevant design range. The first part of the report covers material and elements testing. After the bearings were installed in the building, we performed forced vibration tests in both the horizontal and vertical directions. These test results form the next section. After several experiments, we carried out earthquake observations. We report on the effectiveness of the system in reducing response acceleration during a small displacement. This system was installed in the building in March 1992