International Nuclear Information System (INIS)

We propose a scheme for the generation of the cluster states for many atoms in cavity QED. In our scheme, the atoms are sent through nonresonant cavity fields in the vacuum states. The cavity fields are only virtually excited and no quantum information will be transferred from the atoms to the cavity fields. The advantage is that the cavities are suppressed during the procedure. The scheme can also be generalized to the ion trap system.

International Nuclear Information System (INIS)

Direct nuclear reactions are commonly understood in terms of distorted wave (DW) formalisms. In the case of a single nucleon knockout or transfer reaction the DW analysis provides a reasonable understanding of the observed data. On the other hand the predictions based on different available information inputs have been verified with the observations consistently. In the case of direct reactions involving nuclear clusters however, the DW predictions have been found to disagree with the observations in most cases. The outcome of these and other improvements in the intermediate energy nuclear phenomena involving direct reactions are highlighted. (author). 13 refs., 18 figs.

Science.gov (United States)

Staggered arrays of dimples printed on opposite surfaces of a cooling channel is formulated numerically and optimized with hybrid multi-objective evolutionary algorithm and Pareto optimal front. As Pareto optimal front produces a set of optimal solutions, the trends of objective functions with design variables are predicted by hybrid multi-objective evolutionary algorithm. The problem is defined by three non-dimensional geometric design variables composed of dimpled channel height, dimple print diameter, dimple spacing, and dimple depth, to maximize heat transfer rate compromising with pressure drop. Twenty designs generated by Latin hypercube sampling were evaluated by Reynolds-averaged Navier-Stokes solver and the evaluated objectives were used to construct Pareto optimal front through hybrid multi-objective evolutionary algorithm. The optimum designs were grouped by k-means clustering technique and some of the clustered ...

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.

Energy Technology Data Exchange (ETDEWEB)

Abstract Not Provided

CERN Document Server

Problem statement: Clustering has a number of techniques that have been developed in statistics, pattern recognition, data mining, and other fields. Subspace clustering enumerates clusters of objects in all subspaces of a dataset. It tends to produce many over lapping clusters. Approach: Subspace clustering and projected clustering are research areas for clustering in high dimensional spaces. In this research we experiment three clustering oriented algorithms, PROCLUS, P3C and STATPC. Results: In general, PROCLUS performs better in terms of time of calculation and produced the least number of un-clustered data while STATPC outperforms PROCLUS and P3C in the accuracy of both cluster points and relevant attributes found. Conclusions/Recommendations: In this study, we analyze in ...

CERN Document Server

In cluster-based routing protocol (CBRP), two-level hierarchical structure is successfully used to reduce over-flooding in wireless Ad Hoc networks. As it is vulnerable to a single point of failure, we propose a new adaptive distributed threshold scheme to replace the cluster head by a group of cluster heads within each cluster, called COUNCIL, and distribute the service of single cluster head to multiple cluster heads using (k,n) threshold secret sharing scheme. An Ad Hoc network formed by COUNCIL based clusters can work correctly when the number of compromised cluster heads is smaller than k. To implement this adaptive threshold scheme in wireless Ad Hoc Networks, membership of the clusters should be defined in an adaptive way. In this paper, we mainly discuss our algorithm for forming COUNCIL ...

CERN Document Server

Globular clusters are found usually in galaxies and they are an excellent tracer of dark matter. Long ago it was suggested that there may exist intracluster globular clusters (IGCs) bound to a galaxy cluster rather than to any single galaxy. Here we present a map showing the large scale distribution of globular clusters over the entire Virgo cluster. It shows that IGCs are found out to 5 million light years from the Virgo center, and that they are concentrated in several substructures much larger than galaxies. These objects might have been mostly stripped off from low-mass dwarf galaxies.

UK PubMed Central (United Kingdom)

BackgroundThe search for cluster structure in microarray datasets is a base problem for the so-called "-omic sciences". A difficult problem in clustering is how to handle data with...Full Text Available

International Nuclear Information System (INIS)

The dynamics of a cluster-type system formed by constant total number of molecules, M, is studied when clusters change their sizes by nearest-size transitions (the Szilard model) with time-dependent boundary conditions and non-zero initial cluster size distribution. We compare these results to those reported previously, when non-stationary cluster size distribution was considered under the condition that only monomers are present in the system at the initial moment t=0, and describe the effect of arbitrary pre-existing clusters on the time evolution of the interacting clusters with different sizes, n. The average group size problem is also solved, and the process of relaxation in the system is studied. authors)

CERN Document Server

We present results from a large volume simulation of Hydrogen reionization. We combine 3d radiative transfer calculations and an N-body simulation, describing structure formation in the IGM, to detail the growth of HII regions around high redshift galaxies. Our simulation tracks 1024^3 dark matter particles, in a box of side length 65.6 Mpc/h. This large volume allows us to accurately characterize the size distribution of HII regions throughout most of the reionization process. At the same time, our simulation resolves many of the small galaxies likely responsible for reionization. It confirms a picture anticipated by analytic models: HII regions grow collectively around highly-clustered sources, and have a well-defined characteristic size, evolving from a sub-Mpc scale at the beginning of reionization to R>10 Mpc towards the end. We present a detailed statistical description of our results, and compare them with a numerical hybrid scheme ...

CERN Document Server

We propose genuine ($k$, $m$)-threshold controlling schemes for controlled teleportation via multi-particle entangled states, where the teleportation of a quantum state from a sender (Alice) to a receiver (Bob) is under the control of $m$ supervisors such that $k$ ($k\\leq m$) or more of these supervisors can help Bob recover the transferred state. By construction, anyone of our quantum channels is a genuine multipartite entangled state of which any two parts are inseparable. Their properties are compared and contrasted with those of the well-known Greenberger-Horne-Zeilinger, W, and linear cluster states, and also several other genuine multipartite entangled states recently introduced in literature. We show that our schemes are secure against both Bob's dishonesty and supervisors' treacheries. For the latter case, the game theory is utilized to prove that supervisors' cheats can be well prevented. In addition to their practical importance, our ...

International Nuclear Information System (INIS)

The cross sections for /sup 250/Fm, /sup 244-246/Cf, /sup 242-244/Cm, and /sup 242/Am/sup g/ produced by the /sup 12/C+ /sup 242/Pu and the /sup 16/O+ /sup 238/U reactions leading to the same compound nucleus of /sup 254/Fm have been measured by using radiochemical methods. The excitation functions show that the difference between the /sup 12/C+ /sup 242/Pu and the /sup 16/O+ /sup 238/U reactions can be attributed mainly to the Coulomb barriers. Our results were compared with others reported previously for /sup 22/Ne+ /sup 232/Th, /sup 12/C+ /sup 238/U, /sup 12/C+ /sup 240,241/Pu, /sup 13/C+ /sup 241/Pu, /sup 16/O+ /sup 233/U, and /sup 16/O+ /sup 242/Pu reaction systems, and support a mechanism involving transfer of #alpha#-particle clusters (C,Be,He) from projectile to target for the production of Cf and Cm isotopes.

CERN Document Server

This paper describes the approach taken to the XML Mining track at INEX 2008 by a group at the Queensland University of Technology. We introduce the K-tree clustering algorithm in an Information Retrieval context by adapting it for document clustering. Many large scale problems exist in document clustering. K-tree scales well with large inputs due to its low complexity. It offers promising results both in terms of efficiency and quality. Document classification was completed using Support Vector Machines.

Norwegian Open Research Archives (NORA)

Full Text Available

CERN Document Server

{The determination of cluster masses is a complex problem that would be aided by information about the cluster shape and orientation (along the line-of-sight).} {It is in this context, that we have developed a scheme for identifying the intrinsic morphology and inclination of a cluster, by looking for the signature of the true cluster characteristics in the inter-comparison of the different deprojected emissivity profiles (that all project to the same X-ray brightness distribution) and by using SZe data when available.} {We deproject the cluster X-ray surface brightness profile under the assumptions of four different geometry and inclination configurations for the observed system; these 4 configurations correspond to four extreme geometry+inclination scenarios. The deprojection in question is performed by the non-parametric algorithm DOPING. The formalism is tested with model ...

CERN Document Server

In this paper we have investigated the performance of PSO Particle Swarm Optimization based clustering on few real world data sets and one artificial data set. The performances are measured by two metric namely quantization error and inter-cluster distance. The K means clustering algorithm is first implemented for all data sets, the results of which form the basis of comparison of PSO based approaches. We have explored different variants of PSO such as gbest, lbest ring, lbest vonneumann and Hybrid PSO for comparison purposes. The results reveal that PSO based clustering algorithms perform better compared to K means in all data sets.

International Nuclear Information System (INIS)

Kinetic Monte Carlo (KMC) computer simulations are performed to determine the kinetics of SIA cluster 'clouds' in the vicinity of edge dislocations. The simulations include elastic interactions amongst SIA clusters, and between clusters and dislocations. Results of KMC simulations that describe the formation of 'SIA clouds' during neutron irradiation of bcc Fe and the corresponding evolution kinetics are presented, and the size and spatial distribution of SIA clusters in the cloud region are studied for a variety of neutron displacement damage dose levels. We then investigate the collective spatio-temporal dynamics of SIA clusters in the presence of internal elastic fields generated by static and mobile dislocations. The main features of the investigations are: (1) determination of the kinetics and spatial extent of defect clouds near static dislocations; (2) assessment of the ...

Science.gov (United States)

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International Nuclear Information System (INIS)

The size distributions of precipitated Ni clusters on the surface of a LaNi_5-based alloy immersed in alkaline solution (alkaline treatment) at 383 K for 0-110 min were precisely determined by combining superparamagnetic analysis and transmission electron microscopy (TEM) observations. The superparamagnetic analysis indicated that the diameters of the Ni clusters were smaller than #approx#25 nm in all samples, while their average values increased approximately from 5 to 9 nm with increasing alkaline treatment time. The spatial distribution of the Ni clusters was successively observed by TEM, which agreed fairly well with the estimated size distribution by superparamagnetic analysis. Therefore, estimation of the actual size distribution of Ni clusters by superparamagnetic analysis was proved to be feasible. Based on the above results, a precipitation process for Ni clusters by ...

CERN Document Server

With the advancement of technology and reduced storage costs, individuals and organizations are tending towards the usage of electronic media for storing textual information and documents. It is time consuming for readers to retrieve relevant information from unstructured document collection. It is easier and less time consuming to find documents from a large collection when the collection is ordered or classified by group or category. The problem of finding best such grouping is still there. This paper discusses the implementation of k-Means clustering algorithm for clustering unstructured text documents that we implemented, beginning with the representation of unstructured text and reaching the resulting set of clusters. Based on the analysis of resulting clusters for a sample set of documents, we have also proposed a technique to represent documents that can further improve the ...

CERN Document Server

Context. Study of open clusters is important not only for learning properties of these objects but also for understanding the process of formation and evolution of stars and the Milky Way. Aims. The paper contains determination of the global (geometrical and physical) characteristics of a large sample of Galactic open clusters from homogeneous near-infrared photometric data and analysis of mutual relations between those characteristics. Methods. The near-infrared JHK photometric data from the 2-Micron All Sky Survey were used to determine new coordinates of the centres, angular sizes and radial density profiles of 849 open clusters in the MilkyWay. Additionally, for 754 of these clusters age, reddening, distance and linear sizes were also derived. The sample contains 140 open clusters which have not been studied before. Results. The analysed sample contains open ...

CERN Document Server

We investigate the thermodynamic and chemical structure of the intracluster medium (ICM) across a statistical sample of 20 galaxy clusters analysed with the Chandra X-ray satellite. In particular, we focus on the scaling properties of the gas density, metallicity and entropy and the comparison between clusters with and without cool cores (CCs). We find marked differences between the two categories except for the gas metallicity, which declines strongly with radius for all clusters (Z ~ r^{-0.31}), outside ~0.02 r500. The scaling of gas entropy is non-self-similar and we find clear evidence of bimodality in the distribution of logarithmic slopes of the entropy profiles. With only one exception, the steeper sloped entropy profiles are found in CC clusters whereas the flatter slope population are all non-CC clusters. We explore the role of thermal conduction in stabilizing the ICM and ...

British Library Electronic Table of Contents (United Kingdom)

Metalloid cluster compounds of group 14 of the general formulae EnRm with n > m (E = Si, Ge, Sn, Pb; R = ligand), where naked as well as ligand bound tetrel atoms are present, represent a novel class of cluster compounds in group 14 chemistry and can be seen as intermediates on the way to the elemental state. Therefore, interesting properties are expected for these compounds, which might complement results from nanotechnology. In this article, first results for germanium are discussed, together with novel build-up reactions on the way to novel materials based on metalloid cluster compounds. GRAPHICAL ABSTRACT[image omitted

Science.gov (United States)

PMID:21910487

Energy Technology Data Exchange (ETDEWEB)

The Si-L X-ray emission spectrum of amorphous hydrogenated silicon (a-Si:H) is presented and discussed. For a qualitative interpretation of the measured spectra cluster calculations of pure Si clusters (SiSi4) and Si clusters with hydrogen (SiSi3H) have been performed using a simplified LCAO-X scheme. In general the level shifts caused by introduction of hydrogen are small compared with the valence band width.

Energy Technology Data Exchange (ETDEWEB)

We study by means of Quantum Monte Carlo simulations based on the Worm Algorithm the low temperature (down to T = 0.05 K) properties of parahydrogen clusters comprising up to 40 molecules. Three different intermolecular interactions are employed: the Silvera-Goldman, the Buck and the Lennard-Jones potential. Despite important discrepancies observed in the numerical estimates of energy and superfluid fraction, the mechanism by which clusters melt at low T is independent of the particular choice of the potential, whose only effect is to alter the temperature scale.

International Nuclear Information System (INIS)

In this contribution we compare the electron scattering processes observed in pure O_2 clusters and mixed clusters like O_2/Ne, O_2/Ar and O_2/N_2. The overlap and positions of the potential curves of O_2 states show the different possible electron attachment processes and also explain the formation of O_2 in clusters. (author).

British Library Electronic Table of Contents (United Kingdom)

Nest locations of breeding birds are often spatially clustered. This tendency to nest together has generally been related to a patchy distribution of nesting habitat in landscape studies, but behavioral studies of species with clustered breeding patterns draw attention to the importance of social and biotic factors. Indeed, it is becoming increasingly apparent that the breeding system of many territorial, migrant birds may be semi-colonial. The reasons for, and extent of, spatial clustering in their breeding systems are not well understood. Our goal was to tease apart the influence of habitat availability and social drivers of clustered breeding in a neotropical migrant species, the hooded warbler (Wilsonia citrina). To test alternative hypotheses related to clustered habitat or conspecifi...

CERN Document Server

We use direct N-body simulations to investigate the evolution of star clusters with large size-scales with the particular goal of understanding the so-called extended clusters observed in various Local Group galaxies, including M31 and NGC6822. The N-body models incorporate a stellar mass function, stellar evolution and the tidal field of a host galaxy. We find that extended clusters can arise naturally within a weak tidal field provided that the tidal radius is filled at the start of the evolution. Differences in the initial tidal filling-factor can produce marked differences in the subsequent evolution of clusters and the size-scales that would be observed. These differences are more marked than any produced by internal evolution processes linked to the properties of cluster binary stars or the action of an intermediate-mass black hole, based on models performed in this work and ...

International Nuclear Information System (INIS)

The authors describe the application of an approximate fuzzy C-means (AFCM) clustering algorithm as a data dimension reduction approach to medical magnetic resonance images (MRI). Image data consisted of one T1-weighted, two T2-weighted, and one T2*-weighted (magnetic susceptibility) image for each cranial study and a matrix of 10 images generated from 10 combinations of TE and TR for each body lymphoma study. All images were obtained with a 1.5 Tesla imaging system (GE Signa). Analyses were performed on over 100 MR image sets with a variety of pathologies. The cluster analysis was operated in an unsupervised mode and computational overhead was minimized by utilizing a table look-up approach without adversely affecting accuracy. Image data were first segmented into 2 coarse clusters, each of which was then subdivided into 16 fine clusters. The final tissue classifications were presented as color-coded ...

Science.gov (United States)

... To maximise heat transfer rates, many heatshield designs make use of heat transfer augmentation devices such as large numbers of pin-fin ...

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Not Available

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

CERN Document Server

Recent wide-field imaging observations of the X-ray luminous cluster RDCSJ1252.9-2927 at z=1.24 uncovered several galaxy groups that appear to be embedded in filamentary structure extending from the cluster core. We make a spectroscopic study of the galaxies in these groups using GMOS on Gemini-South and FORS2 on VLT with the aim of determining if these galaxies are physically associated to the cluster. We find that three groups contain galaxies at the cluster redshift and that they are probably bound to the cluster. This is the first confirmation of filamentary structure as traced by galaxy groups at z>1. We then use several spectral features in the FORS2 spectra to determine the star formation histories of group galaxies. We find a population of relatively red star-forming galaxies in the groups that are absent from the cluster core. While similarly red ...

CERN Document Server

Galactic open clusters are since long recognized as one of the best tools for investigating the radial distribution of iron and other metals. We employed FLAMES at VLT to collect UVES spectra of bright giant stars in a large sample of open clusters, spanning a wide range of Galactocentric distances, ages, and metallicities. We present here the results for four clusters: Berkeley 20 and Berkeley 29, the two most distant clusters in the sample; Collinder 261, the oldest and the one with the minimum Galactocentric distance; Melotte 66. Equivalent width analysis was carried out using the spectral code MOOG and Kurucz model atmospheres to derive abundances of Fe, Al, Mg, Si, Ca, Ti, Cr, Ni, Ba; non-LTE Na abundances were derived by direct line-profile fitting. We obtain subsolar metallicities for the two anticenter clusters Be 20 ([Fe/H]=-0.30, rms=0.02) and Be 29 ([Fe/H]=-0.31, ...

CERN Document Server

We present the results of a search for Extreme Ultraviolet emission in A4059, a cluster with an X-ray emitting cluster gas. Our analysis of Extreme Ultraviolet Explorer (EUVE) Deep Survey observations of this cluster shows that it is associated with diffuse EUV emission. Outside the central 2 arcmin radius the entire EUV emission detected is explained by the low energy tail of the X-ray emitting gas. Within the central 2 arcmin region of the cluster we find a deficit of EUV emission compared to that expected from the X-ray gas. This flux deficit is discussed in the context of the cluster's cooling flow. The results derived for A4059 are compared to EUVE results obtained for other clusters such as Coma, Virgo, A1795, and A2199. As part of the study we have carried out a detailed investigation of the stability of the EUVE Deep Survey detector background. Based on ...

International Science & Technology Center (ISTC)

Safe Transference of Spent Fuel Assemblies from Near-Reactor Storage Pools to Long-term "Dry" Storage

CERN Document Server

We study luminosities of millisecond pulsars in globular clusters by fitting the observed luminosity distribution with single and double power laws. We use simulations to model the observed distribution as the brighter part of some parent distribution for Terzan 5 and try to find a model which simultaneously agrees with the observed diffuse radio flux, total predicted number of pulsars and observed luminosity distribution. We find that wide ranges of parameters for log-normal and power-law distributions give such good models. No clear difference between the luminosity distributions of millisecond pulsars in globular clusters and normal disk pulsars was seen.

Energy Technology Data Exchange (ETDEWEB)

The electronic structure of octahedral metal atom clusters Me/sub 6/ of 3d, 4d, and 5d transition metal atoms (V, Cr; Nb, Mo; Ta, W) has been calculated applying two different quantum-chemical approximation methods (Extended Hueckel (EH) method; SW-Xsub(alpha) method). Equilibrium structures, energy level schemes, Fermi energies and band widths as well as densities of states of clusters are discussed in detail.

UK PubMed Central (United Kingdom)

BackgroundFeature selection is an important pre-processing task in the analysis of complex data. Selecting an appropriate subset of features can improve classification or clustering...Full Text Available

International Nuclear Information System (INIS)

Defect cluster formation in 14-MeV neutron irradiated polycrystalline copper has been observed by transmission electron microscopy (TEM) and correlated with the increase in yield stress. The measurements indicate that the radiation hardening component of the yield strength in polycrystals is not directly additive to the unirradiated yield strength. A transitional behavior was observed for radiation hardening at low fluences, which produces an anomalous variation of the defect cluster barrier strength with fluence. The behavior is attributed to the effect of grain boundaries on slip band transmission. An upper limit for the room temperature barrier strength of defect clusters in neutron-irradiated copper was determined to be #alpha#=0.23. (orig.).

CERN Document Server

A new constraint of clustering for the AMD calculation is proposed. This new constraint gives us large improvement in studying the cluster structure by AMD which sometimes meets difficulty in giving rise to some specific cluster configurations. The usefulness of this new constraint is verified by applying it to the the study of the third $K^\\pi = 0^+$ band of $^{20}$Ne which has been discussed to have $2\\alpha$-$^{12}$C structure. This band has not been easy even to construct by AMD. We see that the AMD+GCM calculation by the use of the new constraint gives rise to the third $K^\\pi = 0^+$ band which contains the $2\\alpha$-$^{12}$C structure as an important component.

Science.gov (United States)

These include, but are not limited to: stellar winds and outflows, post-main- sequence star evolution, binary star evolution, globular cluster structure and ...

UK PubMed Central (United Kingdom)

SUMMARYExpression profile analysis clusters Gpnmb with known pigment genes, Tyrp1, Dct, and Si. During development,...Full Text Available

Science.gov (United States)

These include, but are not limited to: stellar winds and outflows, post-main- sequence stellar evolution, binary/multiple star evolution, globular cluster structure ...

Energy Technology Data Exchange (ETDEWEB)

The foundation of a drill unit for cluster drilling of wells is proposed, which includes support, intermediate, and primary girders, forward and rear carts attached to them, railways and traction units. In order to improve operating reliability of the device during unloading on the cart during drilling and placement of the elevator and movement of the foundation within the area of the cluster of boreholes, it is equipped with controllable rods for connecting the carts to one another with the power component. Each of the power components is attached by hinges to a cart and intermediate girder, while the railways with parts are located on supporting girders. The forward carts are connected to the traction units. In order to reduce labor in moving the foundation to a new borehole of the cluster the foundation has brackets and temporary support. The power components have braces which are connected by hinges to them in the ...

CERN Document Server

We investigate the extent to which the pure magnification effect of gravitational lensing can be extracted from galaxy clustering statistics, by a nulling method which aims to eliminate terms arising from the intrinsic clustering of galaxies. The aim is to leave statistics which are free from the uncertainties of galaxy bias. We find that nulling can be done effectively, leaving data which are relatively insensitive to uncertainties in galaxy bias and its evolution, leading to cosmological parameter estimation which is effectively unbiased. This advantage comes at the expense of increased statistical errors, which are in some cases large, but it offers a robust alternative analysis method to cosmic shear for cosmological imaging surveys designed for weak lensing studies, or to full modelling of the clustering signal including magnification effects.

Energy Technology Data Exchange (ETDEWEB)

The electronic structure of small niobium clusters Nb/sub n/ (n = 2, 4, 6, 9) has been calculated applying two different quantum-chemical approximation methods (Extended Hueckel (EH) method; SW-X/sub alpha/ method). It was found that both the methods led to the same results concerning equilibrium structures, energy level schemes, Fermi energies and band widths as well as the densities of states of the clusters. In solving solid state problems of transition metals with the aid of the cluster model a better adaptation of the EH method should be expected by adjusting the EH parameters to the SW-X/sub alpha/ results.

UK PubMed Central (United Kingdom)

In this model, without dark matter, the flat rotation curves of galaxies and the mass-to-light ratios of clusters of galaxies are described quantitatively. The hypothesis is that the agent of gravitational...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundThe Prospective Space-Time scan statistic (PST) is widely used for the evaluation of space-time clusters of point event data. Usually a window of cylindrical shape is employed,...Full Text Available

International Nuclear Information System (INIS)

The electronic structure of octahedral metal atom clusters Me_6 of 3d, 4d, and 5d transition metal atoms (V, Cr; Nb, Mo; Ta, W) has been calculated applying two different quantum-chemical approximation methods (Extended Hueckel (EH) method; SW-Xsub(alpha) method). Equilibrium structures, energy level schemes, Fermi energies and band widths as well as densities of states of clusters are discussed in detail.

Science.gov (United States)

Aluminium toxicity is a major problem in agriculture worldwide. Among the cultivated triticeae, rye (Secale cereale L.) is one of the most Al-tolerant and represents an important potential source of Al-tolerance for improvement of wheat. The Alt4 Al-tolerance locus of rye contains a cluster of genes...

International Nuclear Information System (INIS)

Simulation irradiation experiments were carried out to investigate the formation processes and contribution to hardening of radiation-induced features in low alloy steels. Medium Cu (0.12 and 0.16%) and low Cu (0.03%) A533B steels were irradiated with 3 MeV Ni ions and 5 MeV electrons, and in KUR at 290degC. Irradiated steels were examined by three-dimensional atom probe, positron annihilation, high-resolution transmission electron microscopy and hardness measurements. Electron irradiation caused almost the same hardening as KUR irradiation in medium Cu steels under almost the same dose rate and dose conditions, whereas the formation of larger, denser and more Cu enriched clusters and smaller accumulation of single vacancies were confirmed for KUR irradiation. This indicated that cascade damage provides additional cluster nucleation sites to compensate for lower free point defect production. High dose rate Ni ion irradiation produced Mn-Ni-Si ...

International Nuclear Information System (INIS)

Seeing convolved two-dimensional de Vaucouleurs profiles have been fitted to digital images of the brightest elliptical galaxies in two nearby groups of galaxies and three clusters of galaxies with redshifts in the range 0.06 to 0.15. The digital images were created by scanning electronographic plates obtained by the use of several versions of the RGO electronographic camera. The linear relation between effective surface brightness #mu#/sub e/ and the logarithm of the effective radius r/sub e/, first discovered by Kormendy to be valid for nearby elliptical galaxies, is found to be equally valid for the largest and brightest galaxies in rich clusters of galaxies. The apparent universal nature of that relation indicates that the same type of processes might have been involved during the formation of all ellipticals from cD galaxies in clusters to fainter ellipticals in small groups. It is suggested that the (I/sub e/,r/sub ...

Energy Technology Data Exchange (ETDEWEB)

A simulation model for boron diffusion which takes into account the aggregation of the excess interstitials in clusters, and subsequently, the dissolution of these defects, is proposed. The interstitial supersaturation and generation rate are determined according to the classical theory of nucleation and growth of particles, in analogy with the precipitation of a new phase in heavily doped silicon. The clusters are considered as precipitates formed by interstitial Si atoms. The B diffusion is modelled on the basis of the dopant-interstitial pair diffusion mechanism. The clusters dissolution during annealing maintains nearly constant, for a long period, the interstitial supersaturation and the related enhancement of the boron diffusion. This gives a good account of the diffusion results over a large range of experimental conditions. Furthermore, this approach describes most of the behavior of the transient enhanced diffusion ...

International Nuclear Information System (INIS)

The project is intended to yield information on the transfer factors describing the transfer of ingested radionuclides to breast milk for the following elements: antimony, cerium, chromium, cobalt, gallium, lanthanum, molybdenum, niobium, radium, ruthenium, silver, thorium, titanium, and uranium. Those yet unknown or poorly known transfer factors are required in order to be able to develop a reliable model for description and assessment of the transfer of the radionuclides and the possibly resulting hazardous doses to infants, and for subsequent formulation of recommendations for radiological protection of the population. (orig./CB)

International Nuclear Information System (INIS)

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

Energy Technology Data Exchange (ETDEWEB)

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

UK PubMed Central (United Kingdom)

Charge-charge interactions dramatically influence the dissociation and proton transfer reactivity of large multiply protonated ions. In combination with tandem mass spectrometry, proton transfer...Full Text Available

CERN Document Server

Preparation of covalently modified organic-inorganic composite nanoparticles and their interfacial electron transfer researches

Science.gov (United States)

heat transfer augmentation was found to increase with decreasing length scale but no optimum length scale was found. Heat transfer augmentation due to turbu- ...

CERN Multimedia

An ion beam has been successfully transfered from the SPS to the LHC for the first time on 12 November 2007.

CERN Document Server

We report the results of the evaluation of the ``concentration-density'' relation of galaxies in the local universe, taking advantage of the very large and homogeneous data set available from the Las Campanas Redshift Survey (Shectman et al. 1996). This data set consists of galaxies inhabiting the entire range of galactic environments, from the sparsest field to the densest clusters, thus allowing us to study environmental variations without combining multiple data sets with inhomogeneous characteristics. Concentration is quantified by the automatically-measured concentration index $C$, which is a good measure of a galaxy's bulge-to-disk ratio. The environment of the sample galaxies is characterized both by the three-space local galaxy density and by membership in groups and clusters. We find that the distribution of C in galaxy populations varies both with local density and with cluster/group membership: the fraction of ...

British Library Electronic Table of Contents (United Kingdom)

We present structure calculations of neutral and singly ionized Mg clusters of up to 30 atoms, as well as Na clusters of up to 10 atoms. The calculations have been performed using density functional theory (DFT) within the local (spin-)density approximation, ion cores are described by pseudopotentials. We have utilized a new algorithm for solving the Kohn-Sham equations that is formulated entirely in coordinate space and, thus, permits straightforward control of the spatial resolution. Our numerical method is particularly suitable for modern parallel computer architectures; we have thus been able to combine an unrestricted simulated annealing procedure with electronic structure calculations of high spatial resolution, corresponding to a plane-wave cutoff of 954 eV for Mg. We report the geo...

British Library Electronic Table of Contents (United Kingdom)

This paper addresses the problem of partitioning a local service region into nonoverlapping work areas in which pickups and deliveries are made throughout the day. For a fleet of homogeneous vehicles, a given set of customers, and expected demand for service, the objective is to find the least number of work areas or clusters that satisfy a variety of geometric and capacity constraints. Using rectangles as the basic shape, each cluster must have an aspect ratio that falls within certain bounds, as well as meet load and time requirements dictated by the capacity of a vehicle and the working hours in a day, respectively. The latter requirement presents a unique hurdle because travel times are a function of the actual routes followed by the drivers, and are not known, even in a probabilistic ...

CERN Document Server

Dark matter particles form halos that contribute the major part of the mass of galaxy clusters. The formation of these cosmological structures have been investigated both observationally and in numerical simulations, which have confirmed the existence of a universal mass profile. However, the dynamic behaviour of dark matter in halos is not as well understood. We have used observations of 16 equilibrated galaxy clusters to show that the random velocities of dark matter particles are larger on average along the radial direction than along the tangential, and that the magnitude of this velocity anisotropy is radially varying. Our measurement implies that the collective behaviour of dark matter particles is fundamentally different from that of normal particles and the radial variation of the anisotropy velocity agrees with the predictions of numerical simulation.

CERN Document Server

In this paper we present a model and simulator for many clusters of heterogeneous PCs belonging to a local network. These clusters are assumed to be connected to each other through a global network and each cluster is managed via a local scheduler which is shared by many users. We validate our simulator by comparing the experimental and analytical results of a M/M/4 queuing system. These studies indicate that the simulator is consistent. Next, we do the comparison with a real batch system and we obtain an average error of 10.5\\% for the response time and 12\\% for the makespan. We conclude that the simulator is realistic and well describes the behaviour of a large-scale system. Thus we can study the scheduling of our system called \\dirac in a high throughput context. We justify our decentralized, adaptive and opportunistic approach in comparison to a centralized approach in such a context.

International Nuclear Information System (INIS)

In a sufficiently large cluster of several polar molecules, collective interactions lead to localization or 'solvation' of electrons. The existence of the solvated electron is known since 1863 in liquid ammonia and since 1962 for liquid water. In 1984, electron localization in clusters was experimentally demonstrated in (H_2O)_N_#>=#_1_1 and (NH_3)_N_#>=#_3_4 clusters. In cooperation with K. Bowen, we recently initiated a test of the theory of electron binding by a dipole and a new ground state dipole bound dimer anion, (H_2O..NH_3), was predicted and observed. We here describe results of a search for new dipole-bound and solvated electron systems. (author).

International Nuclear Information System (INIS)

We have obtained radial velocities for 69 stars in the globular cluster M2 (NGC 7089). M2's rotation axis is, within sizeable uncertainties, perpendicular to the major axis determined by the flattening. The ratio of rotational to random kinetic energy agrees with that predicted from the ellipticity assuming an oblate figure and an isotropic velocity-dispersion tensor. We have fitted King-Michie models to determine M2's mass, the exponent of an assumed power-law mass function, and the anisotropy radius. The most significant sources of uncertainty in the modeling are the velocity dispersion, the distance, and the mass-luminosity relation for the cluster stars. The models favor mass functions similar to or shallower than the Salpeter initial-mass function and a moderate amount of velocity anisotropy.

International Nuclear Information System (INIS)

Hyperspherical-harmonics method to investigate the lightest nuclei having three-cluster structure is discussed together with recent experiments. Properties of bound states and methods to explore three-body continuum are presented. The challenges created by large neutron excess and halo phenomena are highlighted. Astrophysical aspects of the "7Li + n "#-># "8Li + #gamma# reaction and the solar-boron-neutrinos problem are analyzed. Three-cluster structure of highly excited states in "8Be is shown to be responsible for extreme isospin mixing. Progress in studies of "6He- and "1"1Li-induced inclusive and exclusive nuclear reactions is demonstrated, providing information on the nature of continuum structures of Borromean nuclei.

Energy Technology Data Exchange (ETDEWEB)

The increasing use of quantum-chemical methods in catalysis has underscored the importance of developing and improving semiempirical approximations oriented toward calculations of the total energy and geometry, offering a means for examining intermolecular interactions. In this article a general approach is proposed, using weighting factors for certain regions of distances, i.e., introducing different parametrization into the various regions. A scheme designated MINDO/3-HB is presented as an extension of the MINDO/3 scheme to the region of hydrogen bonds and ..pi..-complexes of olefins with Broensted acid centers (BACs). Examples of cluster calculations are given for the adsorption of ammonia, pyridine, ethylene, and ethanol on the BACs of zeolites. In the example of the process of zeolite synthesis, the possibilities of the cluster approach are discussed for calculations related to the formation of catalysts.

Science.gov (United States)

Transition-metal chemistry in ionic liquids (IL) has achieved intrinsic fascination in the last few years. The use of an IL as environmental friendly solvent, offers many advantages over traditional materials synthesis methods. The change from molecular to ionic reaction media leads to new types of materials being accessible. Room-temperature IL have been found to be excellent media for stabilising transition-metal clusters in solution and to crystallise homo- and heteronuclear transition-metal complexes and clusters. Furthermore, the use of IL as solvent provides the option to replace high-temperature routes, such as crystallisation from the melt or gas-phase deposition, by convenient room- or low-temperature syntheses. Inorganic IL composed of alkali metal cations and polynuclear transition-metal cluster anions are also known. Each of these areas will be discussed briefly in this contribution. PMID:21743925

International Nuclear Information System (INIS)

Proton and neutron transfer populating low-lying states have been studied in the system "1"4"4Sm+"8"8Sr at an energy below the Coulomb barrier. The experimental cross sections for the single proton transfer are well reproduced by DWBA-calculations using spectroscopic information from light ion reactions. The two-proton transfer appears enhanced relative to the uncorrelated sequential transfer of single protons. The same holds for the transfer of proton pairs, the enhancement is kept for the second pair. This is interpreted as a supercurrent between two superfluid nuclear proton-pair wave functions: More mass and charge is transported per time unit in pairs than by single nucleons. Neutron transfer is observed with large cross sections and is found to contribute to the energy loss observed in the transfer reactions. For mixed proton-neutron ...

UK PubMed Central (United Kingdom)

Pathogenicity islands (PAIs) are chromosomal clusters of pathogen-specific virulence genes often found at tRNA loci. In the Yersinia pseudotuberculosis 32777 chromosome, we characterized...Full Text Available

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Objectives: Human influenza A (H1N1) 2009 has caused severe epidemics in many countries, but its dynamics in spatial and temporal contexts have so far been poorly appreciated. Methods: A total of 24,414 laboratory confirmed human influenza A (H1N1) 2009 cases reported from May to September 2009 in Hong Kong were evaluated, using a Geographic Information System (GIS)-based approach. Spatio-temporal clustering was assessed after dividing Hong Kong into 4 geographic sectors, 18 districts and 500 m x 500 m cells. Global Moran's I, Local Moran's I and SaTScan(TM) were used in the exploration. Results: Spatio-temporal clusters first appeared on Hong Kong Island at week 3, alongside multiple foci suggestive of infection nidus introduced from abroad. The clusters grew rapidly and became confluent ...

CERN Document Server

The Sunyaev-Zeldovich (SZ) effect gives a measure of the thermal energy and electron pressure in groups and clusters of galaxies. In the near future SZ surveys will map hundreds of systems, shedding light on the pressure distribution in the systems. The thermal energy is related to the total mass of a system of galaxies, but it is only a projection that is observed through the SZ effect. A model for the 3D distribution of pressure is needed to link the SZ signal to the total mass of the system. In this work we construct an empirical model for the 2D and 3D SZ profile, and compare it to a set of realistic high resolution SPH simulations of galaxy clusters and groups, and to a stacked SZ profile for massive clusters derived from WMAP data. Furthermore, we combine observed temperature profiles with dark matter potentials to yield an additional constraint, under the assumption of hydrostatic equilibrium. We find a very tight ...

UK PubMed Central (United Kingdom)

BackgroundIn many of the European countries affected by Bovine Spongiform Encephalopathy (BSE), case clustering patterns have been observed. Most of these patterns have been interpreted...Full Text Available

UK PubMed Central (United Kingdom)

Previous studies have been conducted in gene expression profiling to identify groups of genes that characterize the colorectal carcinoma disease. Despite the success of previous attempts to identify...Full Text Available

UK PubMed Central (United Kingdom)

ObjectiveTo refine the CT prediction of emphysema by comparing histology and CT for specific regions of lung. To incorporate both regional lung density measured by CT and cluster...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The A(..pi../sup +/,/sup 3/He)B reaction near threshold is studied in a model where the pion is absorbed by an /sup 4/He constituent of the target nucleus. The predictions of this model using harmonic oscillator cluster wave functions agree semi-quantitatively with the experimental data on the inverse reaction.

UK PubMed Central (United Kingdom)

Noncoding RNAs play important roles in various aspects of gene regulation. We have identified 7SK RNA to be enriched in nuclear speckles or interchromatin granule clusters (IGCs), a subnuclear domain...Full Text Available

CERN Document Server

We present the results of an isophotal shape analysis of three samples of galaxies in the Coma cluster. Quantitative morphology, together with structural and photometric parameters, is given for each galaxy. Special emphasis has been placed on the detailed classification of early-type galaxies. The three samples are: i) a sample of 97 early-type galaxies brighter than m_B = 17.00 falling within one degree from the center of the Coma cluster; these galaxies were observed with CCD cameras, mostly in good to excellent resolution conditions; ii) a magnitude complete sample of 107 galaxies of all morphological types down to m_B = 17.00 falling in a circular region of 50 arcmin diameter, slightly offcentered to the North-West of the cluster center; the images for this and the next sample come from digitized photographic plates; iii) a complete comparison sample of 26 galaxies of all morphological types down to m_R = 16.05 (or m_B ...

UK PubMed Central (United Kingdom)

In the course of a prenatal diagnosis for beta thalassaemia by linkage analysis of restriction fragment length polymorphisms, a homozygous beta thalassaemia fetus was misdiagnosed as beta thalassaemia...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundMass treatment to trachoma endemic communities is a critical part of the World Health Organization SAFE strategy. However, non-participation may not be at random, affecting...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundMuch of our current understanding of the epidemiology of Ascaris lumbricoides infections in humans has been acquired by analyzing worm count data. These...Full Text Available

UK PubMed Central (United Kingdom)

Extended-spectrum beta-lactamases (ESBL) constitute a key antibiotic-resistance mechanism affecting Gram-negative bacteria, and also an excellent model for studying evolution in real time. A shift in...Full Text Available

CERN Document Server

The expression levels of many thousands of genes can be measured simultaneously by DNA microarrays (chips). This novel experimental tool has revolutionized research in molecular biology and generated considerable excitement. A typical experiment uses a few tens of such chips, each dedicated to a single sample - such as tissue extracted from a particular tumor. The results of such an experiment contain several hundred thousand numbers, that come in the form of a table, of several thousand rows (one for each gene) and 50 - 100 columns (one for each sample). We developed a clustering methodology to mine such data. In this review I provide a very basic introduction to the subject, aimed at a physics audience with no prior knowledge of either gene expression or clustering methods. I explain what genes are, what is gene expression and how it is measured by DNA chips. Next I explain what is meant by "clustering" and how we analyze ...

UK PubMed Central (United Kingdom)

BackgroundThe implementation of high throughput sequencing for exploring biodiversity poses high demands on bioinformatics applications for automated data processing. Here we introduce...Full Text Available

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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)

UK PubMed Central (United Kingdom)

Aluminum toxicity is a major problem in agriculture worldwide. Among the cultivated Triticeae, rye (Secale cereale L.) is one of the most Al tolerant and represents an important potential...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundWith rates of childhood obesity increasing, physical activity (PA) promotion especially in young children has assumed greater importance. Given the limited effectiveness...Full Text Available

CERN Document Server

We have discovered seven type Ia cluster supernovae (SNe) in the course of the Wise Observatory Optical Transients Search in the fields of galaxy clusters with redshifts between z=0.06 and z=0.2. Two of these events, SN 1998fc in Abell 403 (z=0.10) and SN 2001al in Abell 2122/4 (z = 0.066), have no obvious hosts. Both events appear projected on the halos of the central cD galaxies, but have velocity offsets of 750-2000 km/s relative to those galaxies, suggesting they are not bound to them. We use deep Keck imaging of the locations of the two SNe to put upper limits on the luminosities of possible dwarf hosts, M_R > -14 mag for SN 1998fc and M_R > -11.8 mag for SN 2001al. The fractions of the cluster luminosities in dwarf galaxies fainter than our limits are less than 3 x 10^-3 and 3 x 10^-4, respectively. Thus, 2/7 of the SNe would be associated with less than 3 x 10^-3 of the luminosity attributed to galaxies. We ...

International Nuclear Information System (INIS)

The fission fragments from spontaneous fission of 252Cf have been measured with the spectrometric and position-sensitive semiconductor pixel detector Medipix2. Fragments are identified by pattern recognition of clusters generated in the Medipix2 pixel matrix sensor upon heavy particle hit. From analysis of cluster area, the distribution of kinetic energy of fission fragments is obtained. Together with a novel USB readout interface, the Medipix2/USB system operates as active nuclear emulsion in single-quantum and on-line tracking mode.

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A method based on cluster analysis techniques is proposed in order to obtain representative local wind patterns. Modeling renewable energy systems, in an accurate way which strongly depends on wind loads, requires reliable data to analyze their response and evaluate their performance. Otherwise poor agreement with the models may be obtained. In a case study for La Paz, Baja California Sur, Mexico, four different wind patterns were obtained from a one-year data set recorded at 10-min intervals. (author)

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Fractal dimensional analysis was employed to obtain a quantitative measure of the morphology of polymer networks formed by UV irradiation induced polymerization of photo-reactive mesogenic monomers dissolved in a liquid crystal host medium. The fractal dimensions obtained, may be interpreted by polymer network growth following a percolation-like model for monomer concentrations well below the solubility limit. On passing the solubility limit, the polymerization process changes from a (radical chain) solution polymerization to a dispersion polymerization, with fractal dimensions decreasing and suggesting a cluster-cluster aggregation process for monomer concentrations above the solubility limit, similar to the aggregation of colloidal particles.

International Nuclear Information System (INIS)

The electronic structure of the clusters [V_3Si_4]"1"2"-, [Nb_3Sn_4]"1"2"-[Mo_3Ge_4]"1"5"- in crystalline V_3Si, Nb_3Sn, Mo_3Ge compounds is calculated by the Extended Hueckel method. The influence of different types of radiation induced defects on the density of states at the Fermi level (the anti-site defects, the displacement of atoms in linear chains, the vacancy-interstitial type defects) is considered. (author).

British Library Electronic Table of Contents (United Kingdom)

Phelps N. A. Cluster or capture? Manufacturing foreign direct investment, external economies and agglomeration, Regional Studies.?This paper reviews the nature and significance of external economies associated with multinational enterprise (MNE) participation in the manufacturing industries of host economies. It argues that the balance of forces of internalization and externalization is currently skewed towards the former and the interests of MNEs rather than the latter and the interests of local and national communities and governments. A stylized comparison of developmental and competition state interventions in relation to MNEs and their foreign direct investment (FDI) suggests that in the absence of co-ordinated interventions by governments, there will commonly be a failure of t...

CERN Document Server

We study a percolation process on the planted binary tree, where clusters freeze as soon as they become larger than some fixed parameter N. We show that as N goes to infinity, the process converges in some sense to the frozen percolation process introduced by Aldous. In particular, our results show that the asymptotic behaviour differs substantially from that on the square lattice, on which a similar process has been studied recently by van den Berg, de Lima and Nolin.

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... females in vitro intestines lead 203 mucous membranes radionuclide kinetics

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... momentum transfer propagator scattering scattering amplitudes strong

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... administrative procedures developing countries economic development nuclear

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International Nuclear Information System (INIS)

This paper deals with construction types of high temperature heat exchangers, their circulation loops and temperature differences. Most attention is given to gas dynamics, convective heat transfer, convection and radiant heat transfer interaction in high temperature heat exchangers. The ways of heat transfer augmentation and efficient heat exchanger construction are discussed.

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Experimental investigation was carried out for friction factor and heat transfer coefficient in the case of a rotating tube with a twisted-tape insert for heat transfer augmentation. The data obtained were compared with existing data for a stationary tube with a twisted-tape insert. It has been observed that the enhancement in heat transfer offsets the rise in friction factor due to rotation, with respect to a plain tube under stationary conditions. A correlation has been proposed for the data obtained.

International Nuclear Information System (INIS)

In this paper, numerical simulation of a concentric tube heat exchanger is presented to determine the convective heat transfer coefficient and friction factor in a smooth tube. Increasing the convective heat transfer coefficient can increase heat transfer rate in a concentric tube heat exchanger from a given tubular surface area. This can be achieved by using heat transfer augmentation devices. This work constitutes the initial phase of the numerical simulation of heat transfer from tubes employing augmentation devices, such as twisted tapes, wire-coil inserts, for heat transfer enhancement. A computational fluid dynamics (CFD) simulation tool was developed with CFX software and the results obtained from the simulations are validated with the empirical correlations for a smooth tube heat exchanger. The difficulties associated with the simulation of a heat ...

International Nuclear Information System (INIS)

This experiment investigated the effects of free-stream turbulence intensity, length scale, Reynolds number, and leading-edge velocity gradient on stagnation-region heat transfer. Heat transfer was measured in the stagnation region of four models with elliptical leading edges downstream of five turbulence-generating grids. Stagnation-region heat transfer augmentation increased with decreasing length scale but an optimum scale was not found. A correlation was developed that fit heat transfer data for isotropic turbulence to within #+-#4 percent but did not predict data for anisotropic turbulence. Stagnation heat transfer augmentation caused by turbulence was unaffected by the velocity gradient. The data of other researchers compared well with the correlation. A method of predicting heat transfer downstream of the stagnation point was developed. 28 refs., 12 ...

International Nuclear Information System (INIS)

We derive stellar masses, ages, and star formation histories (SFHs) of massive early-type galaxies in the z = 1.237 RDCS1252.9-2927 cluster and compare them with those measured in a similarly mass-selected sample of field contemporaries drawn from the Great Observatories Origin Deep Survey South Field. Robust estimates of these parameters are obtained by comparing a large grid of composite stellar population models with 8-9 band photometry in the rest-frame near-ultraviolet, optical, and IR, thus sampling the entire relevant domain of emission of the different stellar populations. Additionally, we present new, deep U-band photometry of both fields, giving access to the critical far-ultraviolet rest frame, in order to empirically constrain the dependence of the most recent star formation processes on the environment. We also analyze the morphological properties of both samples to examine the dependence of their scaling relations on their mass and environment. We ...

Science.gov (United States)

This investigation concerns the nonlinear dynamics of heat transfer from a surface using an upstream eddy promoter. A numerical model is developed for the coupled fluid flow and heat transfer process based on a modified MacCormack scheme. Numerical simulations are carried out to determine the response and heat transfer enhancement due to the promoter. The average heat transfer from a cavity floor is seen to be increased by a factor of approximately five over the unpromoted'' flow. Another interesting feature of the study is the nonlinear viscous flow dynamics from the cylinder-wall interaction which differ significantly from the familiar cylinder-free stream patterns.

International Nuclear Information System (INIS)

Heat transfer augmentation has developed into a major specialty area in heat transfer research and development. A bibliography of world literature on augmentation is presented. The literature is classified into passive augmentation techniques, which require no external power, and active techniques, which do require external power. The fourteen techniques are grouped in terms of their application to the various modes of heat transfer. Mass transfer is included for completeness. Key words are included with each citation for technique/mode identification. The total number of publications cited is 1,967, including 75 surveys of various techniques and 42 papers on performance evaluation of passive techniques. Patents are not included as they will be the subject of a future topical report.

Energy Technology Data Exchange (ETDEWEB)

A heat transfer (condenser) of a domestic freezer was tested in a vertical channel in order to study the influence of the chimney effect in the optimization of the heat transfer coefficient. The variation of the opening of the channel, position and the heating power of the heat exchanger in the heat transfer coefficient was considered. The influence of the surface emissivity on the heat transfer by thermal radiation was studied with the heat exchanger testes without paint and with black paint. The air velocity entering the channel was measured with a hot wire anemometer. In order to evaluate the chimney effect, the heat exchanger was testes in a open ambient. This situation simulates its operational conditions when installed on the freezer system. The variables collected in the experimental procedures was gathered in the form of dimensionless parameters as Nusselt, Rayleigh, Grashof and Prandtl numbers, ...

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We create realistic, full-sky, half-arcminute resolution simulations of the microwave sky matched to the most recent astrophysical observations. The primary purpose of these simulations is to test the data reduction pipeline for the Atacama Cosmology Telescope (ACT) experiment; however, we have widened the frequency coverage beyond the ACT bands and utilized the easily accessible HEALPix map format to make these simulations applicable to other current and near future microwave background experiments. Some of the novel features of these simulations are that the radio and infrared galaxy populations are correlated with the galaxy cluster and group populations, the primordial microwave background is lensed by the dark matter structure in the simulation via a ray-tracing code, the contribution to the thermal and kinetic Sunyaev-Zel'dovich (SZ) signals from galaxy clusters, groups, and the intergalactic medium has been included, and the gas ...

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The interaction between a lower hybrid wave and a fusion alpha particle displaces the alpha particle simultaneously in space and energy. This results in coupled diffusion. Diffusion of alphas down the density gradient could lead to their transferring energy to the wave. This could, in turn, put energy into current drive. Here we calculate numerical solutions for the alpha energy transfer and study a range of conditions that are favourable for wave amplification from alpha energy. We find that it is possible for fusion alpha particles to transfer a large fraction of their energy to the lower hybrid wave. The numerical calculation shows that the net energy transfer is not sensitive to the value of the diffusion coefficient over a wide range of practical values. An extension of this idea, the use of a lossy boundary to enhance the energy transfer, is investigated. This technique is ...

Energy Technology Data Exchange (ETDEWEB)

The interaction between a lower hybrid wave and a fusion alpha particle displaces the alpha particle simultaneously in space and energy. This results in coupled diffusion. Diffusion of alphas down the density gradient could lead to their transferring energy to the wave. This could, in turn, put energy into current drive. An initial analytic study was done by Fisch and Rax. Here the authors calculate numerical solutions for the alpha energy transfer and study a range of conditions that are favorable for wave amplification from alpha energy. They find that it is possible for fusion alpha particles to transfer a large fraction of their energy to the lower hybrid wave. The numerical calculation shows that the net energy transfer is not sensitive to the value of the diffusion coefficient over a wide range of practical values. An extension of this idea, the use of a lossy boundary to enhance the energy ...

Energy Technology Data Exchange (ETDEWEB)

An experimental and theoretical study of heat and mass transfer analogy and a comparison of that to a binary liquid mixture evaporation is presented. Common organic solvents, ethanol and n-heptane, were used to form an alcohol - hydrocarbon mixture. Studies were carried out in a horizontal rectangular channel having air flow velocities of 0.2 - 0.9 m/s. Heat transfer coefficients were measured with a copper plate resistor and mass transfer coefficients with a square pool. The heat and mass transfer analogy is presented for a system having two evaporating compounds with a fixed value of air flow and verified by measuring and comparing mass transfer coefficients for distilled water with air flow velocities of 0.2 - 0.9 m/s. An illustrative example of the use of the theory for industrial ventilation is presented. (author)

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Fundamental phenomena of condensation heat transfer at a steam-water interface have been studied related to the thermo-hydrodynamics of the emergency core cooling system for light water reactors. In this study temperature fluctuations near the interface and in the liquid phase were measured using fine thermocouples for a saturated steam-subcooled water co-current stratified two-phase flow in a nearly horizontal rectangular channel, and heat transfer coefficients were determined experimentally. The values of the condensation heat transfer coefficients in this experiment are from 6 to 40 kW/m{sup 2}K. In the regions of high Reynolds numbers, as the steam Reynolds numbers become larger, the average interfacial heat transfer coefficients tend to increase. The corelations of Nusselt numbers were obtained from the heat transfer data. (author)

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A metal matrix is inserted into a phase-change material to enhance the heat transfer during phase-change processes. The metal matrix tends to act like a heat transfer fin from the heated or cooled surface and to increase the effective thermal conductivity of the phase-change fluid. The scope of the study involves numerically modeling the heat transfer to and from constant-temperature cylindrical tubes surrounded by water during the freezing and melting processes. Comparisons of heat transfer with and without the metal matrix are made, with different porosities and densities of the metal matrix being examined. The results of this study are discussed in terms of the effectiveness of the metal matrix as a heat transfer enhancement device.

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A detailed investigation of the damage formation and evolution in ion-implanted crystalline Si is presented. Deep-level transient spectroscopy has been used to monitor room temperature migration of point defect complexes and evolution from simple point-like defect complexes to defect clusters and even extended defects. Si samples were implanted with Si or He ions with energies of 145 keV-3MeV, to fluences in the range 5x10[sup 8]-5x10[sup 13]cm[sup -2]. The effects of thermal annealing, in the range 100-680 C and 10 min-15h, were also explored. A systematic comparison of defect complexes formation and evolution in ion-implanted or electron-irradiated Si samples with a different impurity content were used to assess the role of impurities (C and O), extra implanted ion and defect clustering on the nature and thermal stability of residual damage. In particular, an interstitial excess directly resulting from the extra implanted ion is shown to ...

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Related to other research on the effectiveness of flow boiling heat transfer augmentation using various types of turbulators this investigation comprises a definitive study of the effect of large discrete roughness elements on heat transfer over the entir...

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The effect of velocity gradient on stagnation region heat transfer augmentation by free stream turbulence was investigated. Heat transfer was measured in the stagnation region of four models with elliptical leading edges with ratios of major to minor axes of 1:1, 1.5:1, 2.25:1, and 3:1. Four geometrically similar, square bar, square mesh, biplane grids were used to generate free stream turbulence with different intensities and length. Heat transfer measurements were made for the following ranges of parameters: Reynolds number, based on leading edge diameter, 37,000 to 228,000; dimensionless leading edge velocity gradient, 1.20 to 1.80; turbulence intensity, 1.1 to 15.9%; and length scale to leading edge diameter ratio, 0.05 to 0.30. Stagnation point heat transfer augmentation by free stream turbulence can be predicted using a modified version of a previously developed correlation for a circular leading ...

UK PubMed Central (United Kingdom)

Plasmid transfer between strains of Bacillus thuringiensis subsp. israelensis was studied under a range of environmentally relevant laboratory conditions in vitro,...Full Text Available

International Nuclear Information System (INIS)

The Subseabed Disposal Program has recently completed a 30-day, 0.286-scale laboratory simulation of an In Situ Heat Transfer Experiment (ISHTE), scheduled for eventual deployment in the deep ocean 600 nautical miles north of Hawaii. 10 figures.

International Nuclear Information System (INIS)

This textbook contains the following main topics: Heat conductivity, convection, condensation and evaporation, radiation heat transfer and heat exchangers. It includes the physical foundations for all these aspects and many examples. (orig.)

Science.gov (United States)

Heating and cooling by impinging jets is widely used in various engineering applications, due to the high heat transfer rates prevailing in the vicinity of the stagnation point. The authors have been able to utilize acoustically excited turbulence for the...

UK PubMed Central (United Kingdom)

Equinovarus of the foot is the most common lower extremity deformity following traumatic brain injury. We evaluated outcomes of the split anterior tibialis tendon transfer (SPLATT) for correction of...Full Text Available

UK PubMed Central (United Kingdom)

Nuclear transfer (NT) is a procedure by which genetically identical individuals can be created. The technology of pig somatic NT, including in vitro maturation of oocytes, isolation and treatment of...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

An attempt is made to augment the heat transfer efficiency by means of inserting an oscillating thin plate into a tube of the shell and tube heat exchanger. However, the heat transfer augmenting mechanism has not been fully explained. To elucidate this heat transfer augmenting mechanism, an investigation was given on the heat transfer characteristics of a tube inlet at its preliminary run area when a double-hinged oscillating thin plate is inserted in the inlet. As a result of the experiment, the heat transfer augmentation in the tube as a result of inserting the double-hinged oscillating thin plate was found effective when the preliminary inlet run area is treated as the object. However, in comparison of the effect with the heat transfer in a fully developed turbulent region, it was {eta}- 1. The result thus obtained explains that no sufficient turbulence can ...

CERN Document Server

We present structure calculations of neutral and singly ionized Mg clusters of up to 30 atoms, as well as Na clusters of up to 10 atoms. The calculations have been performed using density functional theory (DFT) within the local (spin-)density approximation, ion cores are described by pseudopotentials. We have utilized a new algorithm for solving the Kohn-Sham equations that is formulated entirely in coordinate space and, thus, permits straightforward control of the spatial resolution. Our numerical method is particularly suitable for modern parallel computer architectures; we have thus been able to combine an unrestricted simulated annealing procedure with electronic structure calculations of high spatial resolution, corresponding to a plane-wave cutoff of 954eV for Mg. We report the geometric structures of the resulting ground-state configurations and a few low-lying isomers. The energetics and HOMO-LUMO gaps of the ground-state ...

International Nuclear Information System (INIS)

Experimental observations related to the initiation of plastic deformation in metals and alloys irradiated with fission neutrons have been analyzed. The experimental results, showing irradiation-induced increase in the upper yield stress followed by a yield drop and plastic instability, cannot be explained in terms of conventional dispersed-barrier hardening because (a) the grown-in dislocations are not free, and (b) irradiation-induced defect clusters are not rigid indestructible Orowan obstacles. A new model called 'cascade-induced source hardening' is presented where glissile loops produced directly in cascades are envisaged to decorate the grown-in dislocations so that they cannot act as dislocation sources. The upper yield stress is related to the breakaway stress which is necessary to pull the dislocation away from the clusters/loops decorating it. The magnitude of the breakaway stress has been estimated and is found to be in good ...

CERN Document Server

We describe a clustering method for labeled link network (semantic graph) that can be used to group important nodes (highly connected nodes) with their relevant link's labels by using PARAFAC tensor decomposition. In this kind of network, the adjacency matrix can not be used to fully describe all information about the network structure. We have to expand the matrix into 3-way adjacency tensor, so that not only the information about to which nodes a node connects to but by which link's labels is also included. And by applying PARAFAC decomposition on this tensor, we get two lists, nodes and link's labels with scores attached to each node and labels, for each decomposition group. So clustering process to get the important nodes along with their relevant labels can be done simply by sorting the lists in decreasing order. To test the method, we construct labeled link network by using blog's dataset, where the blogs are the nodes and labeled links ...

CERN Document Server

NGC 1407 is the central elliptical in a nearby evolved galaxy group apparently destined to become a cluster core. We use the kinematics of globular clusters to probe the dynamics and mass profile of the group's center, out to 60 kpc (~10 R_eff) -- the most extended data set to date around an early-type galaxy. This sample consists of 172 GC velocities, most of them newly obtained using Keck/DEIMOS, with a few additional objects identified as DGTOs or as IGCs. We find weak rotation in the GC system's outer parts, with the metal-poor and metal-rich GCs misaligned. The RMS velocity profile declines rapidly to a radius of ~20 kpc, and then becomes flat or rising to ~60 kpc. There is evidence that the GC orbits have a tangential bias that is strongest for the metal-poor GCs -- possibly contradicting theoretical expectations. We construct cosmologically-motivated galaxy+dark halo dynamical models and infer a mass within 60 kpc of ~3x10^12 M_Sun, ...

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With regard to a fracture system in the Hijiori hot dry rock artificial reservoir, an attempt was made on an interpretation which integrates different data. Major factors that characterize development and performance of an artificial reservoir are composed of a fracture system in rocks, which acts as circulating water paths, a heat exchange face and a reservoir space. The system relates not only with crack density distribution, but also with cracks activated by water pressure fracturing, cracks generating acoustic emission (AE), and cracks working as major flow paths, all of which are characterized by having respective behaviors and roles. Characteristics are shown on AE cluster distribution, crack distribution, production zone and estimated stress fields. Mutual relationship among these elements was discussed based on the Coulomb`s theory. The most important paths are characterized by distribution of slippery cracks. Directions and appearance frequencies of the ...

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The IR double-resonance techniques IR/R2PI (infrared/resonant 2-photon ionization), IR/PIRI (infrared-photo-induced Rydberg ionization) and IR-photodissociation spectroscopy are valuable tools to investigate structure, vibrations, and dynamical processes of neutral and ionic hydrogen-bonded clusters containing aromatic molecules. In this paper we report on the application of the IR double-resonance techniques to determine the NH and OH stretching vibrations of 4-aminophenol and 4-aminophenol(H{sub 2}O){sub 1}, both in the neutral (S{sub 0}) and ionic (D{sub 0}) ground state. All vibrational frequencies obtained for 4-aminophenol and the cluster are compared with the values obtained from ab initio and DFT calculations. In the S{sub 0} state, a trans-linear arrangement of 4-aminophenol(H{sub 2}O){sub 1} is obtained containing an O-H. O hydrogen bond. In the D{sub 0} state an overlay of two spectra can be observed resulting from the trans-linear ...

Science.gov (United States)

A novel multilevel hierarchical Kohonen Net (K-Map) for an intrusion detection system is presented. Each level of the hierarchical map is modeled as a simple winner-take-all K-Map. One significant advantage of this multilevel hierarchical K-Map is its computational efficiency. Unlike other statistical anomaly detection methods such as nearest neighbor approach, K-means clustering or probabilistic analysis that employ distance computation in the feature space to identify the outliers, our approach does not involve costly point-to-point computation in organizing the data into clusters. Another advantage is the reduced network size. We use the classification capability of the K-Map on selected dimensions of data set in detecting anomalies. Randomly selected subsets that contain both attacks and normal records from the KDD Cup 1999 benchmark data are used to train the hierarchical net. We use a confidence measure to label the ...

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The relationship between the fractal dimensions of spatial distributions of aftershocks and pre-existing active faults is examined. Fourteen mainshocks taking place in Japan were followed by aftershocks, and the aftershocks occur in swarms around the mainshocks. The epicentral distributions of the aftershocks exhibit fractal properties, and the fractal dimensions are estimated by using the two-point correlation integral. The pre-existing active fault systems observed in the 14 aftershock regions have fractal structures, and the fractal dimensions are estimated by using the box-counting method. A positive correlation between the estimated fractal dimensions is found, and it is independent on the mainshock magnitude. The correlation shows that aftershock distributions become less clustered with increasing the fractal dimensions of active fault systems. Namely, the fractal clusters of aftershocks are put under the constraint of the fractal ...

CERN Document Server

One class of gravitational wave signals LIGO is searching for consists of short duration bursts of unknown waveforms. Potential sources include core collapse supernovae, gamma ray burst progenitors, and the merger of binary black holes or neutron stars. We present a density-based clustering algorithm to improve the performance of time-frequency searches for the such gravitational-wave bursts when they are extended in time and/or frequency. We have implemented this algorithm as an extension to the QPipeline search for bursts, which currently determines the statistical significance of events based solely on the peak significance observed in minimum uncertainty regions of the time-frequency plane. Density based clustering improves the performance of such a search by considering the aggregate significance of arbitrarily shaped regions in the time-frequency plane and rejecting the isolated minimum uncertainty features expected from the background ...

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(001) CZ silicon wafers were implanted with arsenic (As{sup +}) at energies of 10--50 keV to doses of 2 {times} 10{sup 14} to 5 {times} 10{sup 15}/cm{sup 2}. All implants were amorphizing in nature. The samples were annealed at 700 C for 16 hrs. The resultant defect microstructures were analyzed by XTEM and PTEM and the As profiles were analyzed by SIMS. The As profiles showed significantly enhanced diffusion in all of the annealed specimens. The diffusion enhancement was both energy and dose dependent. The lowest dose implant/annealed samples did not show As clustering which translated to a lack of defects at the projected range. At higher doses, however, projected range defects were clearly observed, presumably due to interstitials generated during As clustering. The extent of enhancement in diffusion and its relation to the defect microstructure is explained by a combination of factors including surface recombination of point defects, As ...

CERN Document Server

Very large databases are required to store massive amounts of data that are continuously inserted and queried. Analyzing huge data sets and extracting valuable pattern in many applications are interesting for researchers. We can identify two main groups of techniques for huge data bases mining. One group refers to streaming data and applies mining techniques whereas second group attempts to solve this problem directly with efficient algorithms. Recently many researchers have focused on data stream as an efficient strategy against huge data base mining instead of mining on entire data base. The main problem in data stream mining means evolving data is more difficult to detect in this techniques therefore unsupervised methods should be applied. However, clustering techniques can lead us to discover hidden information. In this survey, we try to clarify: first, the different problem definitions related to data stream clustering in general; second, ...

CERN Document Server

We have used HST/FOS to study faint UV stars in the core of the nearby globular cluster NGC 6397. We confirm the presence of a 4th cataclysmic variable (CV) in NGC 6397 (CV 4), and we use the photometry of Cool et al. (1998) to present evidence that CVs 1--4 all have faint disks and probably low accretion rates. By combining these results with new UV spectra of CV 1 and the published spectra of Grindlay et al. (1995) we present new evidence that CVs 1--3 may be DQ Her systems, and we show that CV 4 may either be a dwarf nova or another magnetic system. Another possibility is that the CVs could be old novae in hibernation between nova eruptions. We also present the first spectrum of a member of a new class of UV bright stars in NGC 6397. These faint, hot stars do not vary, unlike the CVs, and are thus denoted as ``non-flickerers'' (NFs). Like the CVs, their spatial concentration is strongly concentrated toward the cluster center. Using stellar ...

Science.gov (United States)

... TTP tactics, techniques, and procedures UCP Unified ... be sold or transferred to Pakistan, pursuant to ... substantial amounts of those funds being spent ...

Science.gov (United States)

The present study investigates the effect of the shear rate-dependent thermal conductivity of non-Newtonian fluids on the heat transfer enhancement in a pipe flow. The constant heat flux as thermal boundary condition was adopted in the thermally developed region. The present analytical results show the heat transfer enhancement over those of a shear rate-independent thermal conductivity fluid. The heat transfer coefficient ratio (h/h{sub 0}) linearly increase with the non-dimensional average velocity difference which is the product of the shear rate-dependence of the thermal conductivity and wall-shear rate.

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... table (ASCAMP) system and the Military Strategic and Tactical Relay (Milstar) program. 10 ... Single Channel Antijam Milstar Portable Terminal ...

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

International Nuclear Information System (INIS)

... brakes lmfbr type reactors breeder reactors epithermal reactors fast reactors

Energy Technology Data Exchange (ETDEWEB)

MINEQL is a subroutine package to calculate equilibrium composition of an aqueous system, accounting for mass transfer.

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A comprehensive presentation is made of state-of-the-art configurations and design methodologies for heat transfer devices applicable to industrial processes, automotive systems, air conditioning/refrigeration, cryogenics, and petrochemicals refining. Attention is given to topics in heat exchanger mechanical design, single-phase convection processes, thermal design, two-phase exchanger thermal design, heat-transfer augmentation, and rheological effects. Computerized analysis and design methodologies are presented for the range of heat transfer systems, as well as advanced methods for optimization and performance projection.

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No abstract prepared.

Science.gov (United States)

Unsteady impinging jets are systematically controlled with respect to their time dependence in order to investigate the influence of unsteadiness on the heat transfer performance. This is achieved by a special mass flow control device, which allows almost arbitrary shapes of unsteadiness to be imposed onto the impinging jet. Three different standard signals (sinusoidal, triangular, rectangular) and two specially designed signals are applied and their influence on heat transfer is determined in terms of an enhancement factor. Heat transfer augmentation up to 30% was found and could be physically explained with the help of PIV and hot-wire measurements of the flow field.

International Nuclear Information System (INIS)

This paper presents the results of the experimental investigation on heat transfer and fluid friction characteristics of a class of spiral spring coil used as a tube side forced convection heat transfer augmentation devices. Based on a lot of experimental data, the heat transfer correlation and fluid friction correlation revised by temperature were reached in terms of linear regression. At the same time, proper criteria were used to evaluate the economic performance of the spiral spring inserted tube according to the demand of practical application and some probing analysis were made.

Science.gov (United States)

Topics covered include: Methods of Helium Injection and Removal for Heat Transfer Augmentation; The

International Nuclear Information System (INIS)

This book is organized under the following headings: Electrohydrodynamic heat transfer augmentation; Forced convection augmentation and heat transfer control; Turbulent heat transfer; Thermal problems in the environment; Energy conversion systems; Measurement, visualization, and imaging; Thermal problems in space technology; and Thermal properties.

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The Monte Carlo simulation method is applied to calculate the nucleon transfer part of the imaginary optical-model potential in colliding heavy ions. In the process of transfer of nucleons from one nucleus to the other, forward and backward neutrons and protons are treated separately by taking into consideration the effect of the Coulomb forces and the potential energy surfaces (driving forces). The Pauli exclusion principle is also incorporated properly in the calculation.

Energy Technology Data Exchange (ETDEWEB)

The field trial of an unattended monitoring system for SF transfer verification ended in June 2005. The system is aiming to improve the safeguards measures applied during SF transfers and reduce inspection effort currently required by the Operator, NNCA and the IAEA. They were reviewed based on its technical performance and other issues in this paper.

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In our previous theoretical analyses, solubility-limited mass transfer from waste solids applies if a species is at a constant elemental concentration in liquid at the waste surface. For an element with isotopes that decay appreciably during the time of interest, a solubility boundary condition results in a time-dependent boundary concentration of each isotope. Here we present mass-transfer equations that include the effects of isotopic decay boundary conditions. 9 refs., 1 fig.

Science.gov (United States)

This paper presents a theoretical study of heat transfer from magneto-rheological fluid (MRF) dampers. A lumped system model is developed which is capable of predicting the temperature rise for any size MRF damper. As a case study example, finned and unfinned dampers are compared for automotive-size MRF dampers. The results demonstrate that heat transfer from these devices can be enhanced considerably with the use of fins.

Science.gov (United States)

Analytical solutions are derived for a flow in a semi-infinite vertical porous medium with heat and mass transfer. When the temperature and mass concentration are uniform a constant pressure is possible and sustains a fully developed flow. Thereafter there is a small perturbation on the wall temperature and concentration and the subsequent two-dimensional problem is tackled for a large Prandtl number, free convection parameters and small Reynolds number. The heat transfer rate at the wall is discussed quantitatively.

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This report focuses on a better understanding of the physical phenomenon related to the enhancement of boiling and non-boiling heat transfer by applying ultrasonic waves. Experimental results obtained both in a pool of water and in a vertically upward water flow proved clearly that macroscopic acoustic stream induced by ultrasonics is a major contribution to heat transfer augmentation. (author).

Energy Technology Data Exchange (ETDEWEB)

Granted patents are an important source of information on the potential commercialization of augmented heat transfer technology. This report presents a bibliography of US patents pertinent to that technology. The total number of patents cited is 321. They are presented in three separate lists: by patent number, alphabetically by first inventor, and by augmentation techniques (with secondary arrangement according to mode of heat transfer).

British Library Electronic Table of Contents (United Kingdom)

Abstract We analyse extinction maps of nearby giant molecular clouds to forge a link between driving processes of turbulence and modes of star formation. Our investigation focuses on cloud structure in the column density range above the self-shielding threshold of 1-mag AV and below the star formation threshold - the regime in which turbulence is expected to dominate. We identify clouds with shallow mass distributions as cluster forming. Clouds that form stars in a less clustered or isolated mode show a steeper mass distribution. Structure functions prove inadequate to distinguish between clouds of different star formation mode. They may, however, suggest that the turbulence in the average cloud is governed by solenoidal forcing. The same is found using the -variance analysis which also in...

International Nuclear Information System (INIS)

We present results from a kinetic Monte Carlo simulation of boron transient enhanced diffusion (TED) in silicon. Our approach avoids the use of phenomenological fits to experimental data by using a complete and self-consistent set of values for defect and dopant energetics derived mostly from ab initio calculations. The results predict that, during annealing of 40 keV B-implanted Si at 800 degree C, there exists a time window during which all the implanted boron atoms are substitutional. At earlier or later times, the interactions between free silicon self-interstitials and boron atoms drive the growth of boron clusters and result in an inactive boron fraction. The results show that the majority of boron TED takes place during the growth period of interstitial clusters and not during their dissolution. copyright 1998 American Institute of Physics.

International Nuclear Information System (INIS)

Ion desorption from a condensed gas solid Ne impacted by singly- and multiply-charged Ar"q"+ ions (q = 1-7) has been investigated. Various secondary ions such as cluster ions, Ne"+_n (n = 2-20) as well as atomic ions are observed. Mass spectral patterns, thickness dependence of the yields, and kinetic energy distributions of the desorbed Ne"+_n (n = 1,2) depend strongly on the projectile charge state. These results indicate that the dissipation of the projectile potential energy on the surface leads to the desorption of the monomer and small cluster ions by a Coulomb repulsion between adjacent target ions.

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We introduce a novel scheme for one-way quantum computing (QC) based on the use of information encoded qubits in an effective cluster state resource. With the correct encoding structure, we show that it is possible to protect the entangled resource from phase damping decoherence, where the effective cluster state can be described as residing in a decoherence-free subspace (DFS) of its supporting quantum system. One-way QC then requires either single or two-qubit adaptive measurements. As an example where this proposal can be realized, we describe an optical lattice set-up where the scheme provides robust quantum information processing. We also outline how one can adapt the model to provide protection from other types of decoherence.

International Nuclear Information System (INIS)

Potassium clusters arrayed in zeolite A are known to show ferromagnetic properties at low temperature. The origin of the spontaneous magnetization has been explained by a model of spin-canting in an antiferromagnetically ordered state. The direct information for the magnetic structure, however, has not been obtained so far. In the present work, we measure the neutron powder diffraction by using pulsed neutron source at KEK-KENS below and above the Curie temperature. No significant temperature-dependence was, however, obtained within the statistical errors, namely, magnetic scattering could not be detected separately. We also estimate the intensity of magnetic scattering by assuming some possible magnetic structures with considering the magnetic form factor of the cluster wave function. The intensity of magnetic scattering is estimated to be extremely weak and higher S/N of ?104 or more is required to detect the magnetic scattering of this ...

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The Sputter coefficient of accelerated CO{sub 2} cluster ions hitting surfaces of various materials is investigated. For copper it varies proportional to the 2nd power of the energy between 155 and 260 keV. The rate of erosion for different target materials varies by two orders of magnitude from tungsten to PMMA. Diamond is eroded fairly quickly, while aluminum is eroded less than corundum (Al{sub 2}O{sub 3}). No simple correlation of the sputter coefficient on the bulk material properties is found. For copper the angular distribution of sputtered material is measured and found to be following roughly a cosine distribution. By using masks different microstructures have been produced in cobalt-samarium magnets, diamond and glass. (orig.)

International Nuclear Information System (INIS)

We have measured K-edge X-ray absorption spectra of argon in sputtered aluminum films at a synchrotron radiation facility (the Photon Factory). We found that the energy and shape of white line change when the film is annealed at 500 C and the spectrum becomes resembling that of argon implanted in silicon. From the analyses of the X-ray absorption spectra and TEM observation we concluded that argon exists as very small atom clusters with a diameter less than 1 nm or exist as isolated atoms in the as-sputtered aluminum film, and that the size of the clusters become as big as 10 nm diameter when the film is heated. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

British Library Electronic Table of Contents (United Kingdom)

The dynamics of state of the crystallite-containing magma is studied within the framework of the gas-dynamic model of bubble cavitation. The effect of crystallites on flow evolution is considered for two cases: where the crystallites are cavitation nuclei (homogeneous-heterogeneous nucleation model) and where large clusters of crystallites are formed in the magma in the period between eruptions. In the first case, decompression jumps are demonstrated to arise as early as in the wave precursor; the intensity of these jumps turns out to be sufficient to form a series of discrete zones of nucleation ahead of the front of the main decompression wave. Results of experimental modeling of an explosive eruption with ejection of crystallite clusters (magmatic ?bombs??) suggest that a cocurrent flow...

British Library Electronic Table of Contents (United Kingdom)

An ultrafine-grained ferrite/cementite (UGF/C) steel with a local high density of cementite particles was fabricated through caliber-warm-rolling followed by annealing and resulted in a bimodal-sized microstructure. The characteristic bimodal-sized microstructure was attributed to the original ferrite-pearlite structure and cementite spacing, and reflected the original ferrite-pearlite structure. The smaller-sized clusters corresponded to the former pearlite regions and the larger-sized clusters to the proeutectoid ferrite regions. The cementite particles naturally localized within the former pearlite region. Most of the ferrite coarsening did not occur until the cementite particle spacing reached a critical value. The UGF/C microstructure with a bimodal grain size showed a yield strength ...

CERN Document Server

Microcalcifications in mammogram have been mainly targeted as a reliable earliest sign of breast cancer and their early detection is vital to improve its prognosis. Since their size is very small and may be easily overlooked by the examining radiologist, computer-based detection output can assist the radiologist to improve the diagnostic accuracy. In this paper, we have proposed an algorithm for detecting microcalcification in mammogram. The proposed microcalcification detection algorithm involves mammogram quality enhancement using multirresolution analysis based on the dyadic wavelet transform and microcalcification detection by fuzzy shell clustering. It may be possible to detect nodular components such as microcalcification accurately by introducing shape information. The effectiveness of the proposed algorithm for microcalcification detection is confirmed by experimental results.

International Nuclear Information System (INIS)

A deep band of #left brace#311#right brace# defects was created 520 nm below the silicon surface with a 350 keV Si implant followed by a cluster-forming rapid thermal anneal (800 C, 1000 s). Chemical etching was used to vary the depth to the surface of the #left brace#311#right brace#-defect band. Afterwards, the defect dissolution was investigated at 750 C for different times. Varying the depth in this fashion assures that only the depth and no other feature of the cluster distribution is changed. The #left brace#311#right brace# defects were analyzed by plan-view, transmission electron microscopy. We show that the dissolution time of the #left brace#311#right brace#-defect band varies linearly with depth, confirming that surface recombination controls the dissolution and is consistent with analogous observations of transient enhanced diffusion.

British Library Electronic Table of Contents (United Kingdom)

SummaryProcesses of upgrading and the promotion of industrial "clusters," which encompass multiple policies, institutions, and actors, necessarily vary from place to place. Based on the evidence from Morocco and Tunisia, this article contends that different patterns of business-government relations facilitate different elements of industrial upgrading and cluster promotion. State-dominated political economies may be more amenable to implementing macroeconomic and infrastructure-related measures, which are critical in the initial stages of upgrading. Political economies with more organized business communities may be better equipped to pursue the kinds of inter-firm linkages traditionally associated with later phases of upgrading, when the focus is on boosting innovation.

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We have employed Environmental Scanning Electron Microscopy (ESEM) and Energy Dispersive X-ray (EDX) analysis to study the microstructural evolution of acrylic latex stabilised with a novel polysaccharide derived from agricultural waste. The analysis revealed that the micro structure of the latex in the 'wet' state consists of individual particles and clusters. Upon evaporation a discontinuous film is formed, with voids present within its structure, which is inconsistent with the conventional descriptions of film formation. Further ESEM examination of 'dry' specimens revealed that aging resulted in the formation of dendritic structures on the surfaces of the latex films, which EDX analysis confirmed to have been formed via crystallisation of salt. The experimental evidence suggests that the clusters, which are part of the structure of the latex, may act as nucleation centres that would allow the dendrites to ...

British Library Electronic Table of Contents (United Kingdom)

A numerical study has been conducted to examine the heat transfer from a metal foam-wrapped solid cylinder in cross-flow. Effects of the key parameters including the free stream velocity and characteristics of metal foam such as porosity, permeability, and form drag coefficient on heat and fluid flow are examined. Being a determining factor in pressure drop and heat transfer increment, the porous layer thickness is changed systematically to observe that there is an optimum layer thickness beyond which the heat transfer does not improve while the pressure drop continues to increase. This has been verified by the application of Bejan?s Intersection of Asymptotes method. Results have been compared to those of a finned-tube heat exchanger to observe much higher heat transfer rate with reasonab...

International Nuclear Information System (INIS)

Mass transfer to a wall of a horizontal rectangular channel reactor was investigated by the limiting current technique for Reynolds numbers ranging from 200 to 32000. Overall mass transfer coefficients at various mass transfer surface angles were obtained while the reactor was operated under isothermal and non-isothermal conditions. Dimensionless correlations were developed for isothermal flows from 25 to 55"oC and for non-isothermal flows with applied temperature differences up to 30"oC. In the laminar flow range natural convection dominated, but under turbulent conditions combined natural and forced convection prevailed. Mass transfer was approximately doubled under optimum selection of channel surface rotation, temperature gradient and flow rate. (author)

Science.gov (United States)

Forced convective heat transfer in a cross-corrugated channel solar air heater has been studied experimentally using air as a working fluid. The channel was formed by two transversely positioned corrugated sheets and two flat thermally insulated side walls. One corrugated sheet was heated by a radiant heater, while the other was thermally insulated. The fluid velocity and temperature, and the wall temperature and the local heat flux across the heated corrugated sheet were measured for a variety of operating flow rates. Experimental results for the channel geometry have yielded the correlation Nu = 0.0743 (Re)[sup 0.76]. This heat-transfer coefficient is about 2.8 times that of a smooth flat channel. The experiments showed that local heat transfer rate was smaller on the valley of the corrugation than that on the peak. The ratio of the local heat transfer rates on the two locations was related to the ...

Energy Technology Data Exchange (ETDEWEB)

The portion of the potential energy surface (PES) of acetylacetone relevant for the intramolecular proton transfer reaction is studied using ab initio and DFT methods. The best estimate of the barrier governing proton transfer was found to be 3.4 kcal mol{sup -1} at the MP4(FC)/6-311 + G(2d,2p)//MP2(FC)/6-311 + G(2d,2p) level of theory. Six stationary points on the PES were characterized as well as the reaction paths connecting these points. Special attention paid to the pathway of intramolecular proton transfer reveals that the internal rotation of the methyl group adjacent to the carbonyl group and the proton transfer reaction are consecutive processes.

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The analysis for the WITCH/LINER experiments was performed to investigate the heat transfer characteristics between the gas-agitated steel melt and the vertical surface. The applicability of heat transfer correlations for a gas-agitated fluid system was examined through the numerical analysis of the one-dimensional heat conduction taking into account the crust formation due to the solidification of the steel melt. The heat transfer correlation developed by Konsetov was modified for the application to fluids with low Prandtl number. The constant in the modified correlation was empirically found mainly through the comparison between the analysis and the experiments under conditions that a churn-turbulent two-phase flow regime was anticipated to form. The modified Konsetov correlation could predict the heat transfer characteristics observed through the experiments in an acceptable level. (author)

International Nuclear Information System (INIS)

Counter rotating longitudinal vortices produced by winglet in a channel are known to enhance heat transfer. In the present investigation the flow structure and heat-transfer enhancement by a winglet pair of non-zero thickness has been studied. A delta winglet pair type vortex generator is placed in a hydrodynamically developed and thermally developing laminar channel flow. Computations are done by solving the unsteady, three-dimensional, incompressible Navier-Strokes equations and energy equation using a modified Marker-and-Cell (MAC) method. The flow structure is complex and consists of main, corner and induced vortices. It is observed that as compared to a channel without winglets, the heat transfer is enhanced by 33% when single winglet is used and by 67% when a winglet pair is employed. Effects of thickness of the winglets and Reynolds number on the heat transfer augmentation are presented.

International Nuclear Information System (INIS)

1 - Description of program or function: The COOLOD-N2 code provides a capability for the analyses of the steady-state thermal-hydraulics of research reactors. This code is a revised version of the COOLOD-N code, and is applicable not only for research reactors in which plate-type fuel is adopted, but also for research reactors in which rod-type fuel is adopted. In the code, subroutines to calculate temperature distribution in rod-type fuel have been newly added to the COOLOD-N code. The COOLOD-N2 code can calculate fuel temperatures under both forced convection cooling mode and natural convection cooling mode. A 'Heat Transfer package' is used for calculating heat transfer coefficient, DNB heat flux etc. The 'Heat Transfer package' is a subroutine program and is especially developed for research reactors in which plate-type fuel is adopted. In case of rod-type fuel, DNB heat flux is calculated by both the 'Heat ...

International Nuclear Information System (INIS)

In the presence of hydroxyl anion, both formaldehyde and glyoxal are known to undergo rearrangements involving intermolecular and intramolecular hydride transfer (the Cannizzaro and Benzilic acid rearrangements respectively). The authors report ab initio SCF-MO calculations of the transition state geometries, the activation barriers, and the hydrogen isotope effects for these two reactions. The structure of the transition state for the rection involving formaldehyde is usually basis set dependent, becoming more linear and symmetrical as the basis set size increases. In contrast, the analogous transition state for the glyoxal reaction involves a highly non-linear hydride transfer. They find the isotope effects to be quite low for the Cannizzaro reaction, and significantly larger for the non-linear benzilic acid rection, in apparent contradiction to Westheimer's suggestion the isotope effects reach a maximum for linear hydrogen ...

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Experiments are performed to investigate the single-phase flow and flow-boiling heat transfer augmentation in 3D internally finned and micro-finned helical tubes. The tests for single-phase flow heat transfer augmentation are carried out in helical tubes with a curvature of 0.0663 and a length of 1.15 m, and the examined range of the Reynolds number varies from 1000 to 8500. Within the applied range of Reynolds number, compared with the smooth helical tube, the average heat transfer augmentation ratio for the two finned tubes is 71% and 103%, but associated with a flow resistance increase of 90% and 140%, respectively. A higher fin height gives a higher heat transfer rate and a larger friction flow resistance. The tests for flow-boiling heat transfer are carried out in 3D internally micro-finned helical tube with a curvature of 0.0605 and a length of 0.668 m. Compared with that in ...

Energy Technology Data Exchange (ETDEWEB)

Numerical investigations of three-dimensional flow and heat transfer in a finned tube with punched longitudinal vortex generators (LVG`s) are carried out for Reynolds number of 250 and 300. Air with a Prandtl number of 0.7 is used as the fluid. The flow is both thermally and hydrodynamically developing. The LVG is a delta winglet pair (DWP) punched out of the fin and is located directly behind the tube, symmetrically separated by one tube diameter. The DWP generates longitudinal vortices in the wake of the tube, defers flow separation on the tube, deflects the main stream into the tube wake, and strong reduces the ``dead water zone.`` Heat transfer reversal is avoided by the DWP. Comparison of the span-averaged Nusselt numbers for the fin with and without DWP shows significant local heat transfer enhancement of several hundred percent in the tube wake. For Re = 300 and Fi = 200 the global heat transfer ...