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1

Sampling Within k-Means Algorithm to Cluster Large Datasets  

Science Conference Proceedings (OSTI)

Due to current data collection technology, our ability to gather data has surpassed our ability to analyze it. In particular, k-means, one of the simplest and fastest clustering algorithms, is ill-equipped to handle extremely large datasets on even the most powerful machines. Our new algorithm uses a sample from a dataset to decrease runtime by reducing the amount of data analyzed. We perform a simulation study to compare our sampling based k-means to the standard k-means algorithm by analyzing both the speed and accuracy of the two methods. Results show that our algorithm is significantly more efficient than the existing algorithm with comparable accuracy. Further work on this project might include a more comprehensive study both on more varied test datasets as well as on real weather datasets. This is especially important considering that this preliminary study was performed on rather tame datasets. Also, these datasets should analyze the performance of the algorithm on varied values of k. Lastly, this paper showed that the algorithm was accurate for relatively low sample sizes. We would like to analyze this further to see how accurate the algorithm is for even lower sample sizes. We could find the lowest sample sizes, by manipulating width and confidence level, for which the algorithm would be acceptably accurate. In order for our algorithm to be a success, it needs to meet two benchmarks: match the accuracy of the standard k-means algorithm and significantly reduce runtime. Both goals are accomplished for all six datasets analyzed. However, on datasets of three and four dimension, as the data becomes more difficult to cluster, both algorithms fail to obtain the correct classifications on some trials. Nevertheless, our algorithm consistently matches the performance of the standard algorithm while becoming remarkably more efficient with time. Therefore, we conclude that analysts can use our algorithm, expecting accurate results in considerably less time.

Bejarano, Jeremy [Brigham Young University; Bose, Koushiki [Brown University; Brannan, Tyler [North Carolina State University; Thomas, Anita [Illinois Institute of Technology; Adragni, Kofi [University of Maryland; Neerchal, Nagaraj [University of Maryland; Ostrouchov, George [ORNL

2011-08-01T23:59:59.000Z

2

Using Dynamic Quantum Clustering to Analyze Hierarchically Heterogeneous Samples on the Nanoscale  

SciTech Connect

Dynamic Quantum Clustering (DQC) is an unsupervised, high visual data mining technique. DQC was tested as an analysis method for X-ray Absorption Near Edge Structure (XANES) data from the Transmission X-ray Microscopy (TXM) group. The TXM group images hierarchically heterogeneous materials with nanoscale resolution and large field of view. XANES data consists of energy spectra for each pixel of an image. It was determined that DQC successfully identifies structure in data of this type without prior knowledge of the components in the sample. Clusters and sub-clusters clearly reflected features of the spectra that identified chemical component, chemical environment, and density in the image. DQC can also be used in conjunction with the established data analysis technique, which does require knowledge of components present.

Hume, Allison; /Princeton U. /SLAC

2012-09-07T23:59:59.000Z

3

ANALYZING STAR CLUSTER POPULATIONS WITH STOCHASTIC MODELS: THE HUBBLE SPACE TELESCOPE/WIDE FIELD CAMERA 3 SAMPLE OF CLUSTERS IN M83  

SciTech Connect

The majority of clusters in the universe have masses well below 10{sup 5} M{sub Sun }. Hence, their integrated fluxes and colors can be affected by the presence or absence of a few bright stars introduced by stochastic sampling of the stellar mass function. Specific methods are being developed to extend the analysis of cluster energy distributions into the low-mass regime. In this paper, we apply such a method to real observations of star clusters, in the nearby spiral galaxy M83. We reassess the ages and masses of a sample of 1242 clusters for which UBVIH{alpha} fluxes were obtained from observations with the Wide Field Camera 3 instrument on board the Hubble Space Telescope. Synthetic clusters with known properties are used to characterize the limitations of the method (valid range and resolution in age and mass, method artifacts). The ensemble of color predictions of the discrete cluster models are in good agreement with the distribution of observed colors. We emphasize the important role of the H{alpha} data in the assessment of the fraction of young objects, particularly in breaking the age-extinction degeneracy that hampers an analysis based on UBVI data only. We find the mass distribution of the cluster sample to follow a power law of index -2.1 {+-} 0.2, and the distribution of ages a power law of index -1.0 {+-} 0.2 for log (M/ M{sub Sun }) > 3.5, and ages between 10{sup 7} and 10{sup 9} yr. An extension of our main method, which makes full use of the probability distributions of age and mass obtained for the individual clusters of the sample, is explored. It produces similar power-law slopes and will deserve further investigation. Although the properties derived for individual clusters significantly differ from those obtained with traditional, non-stochastic models in about 30% of the objects, the first-order aspect of the age and mass distributions is similar to those obtained previously for this M83 sample in the range of overlap of the studies. We extend the power-law description to lower masses with better mass and age resolution and without most of the artifacts produced by the classical method.

Fouesneau, Morgan; Lancon, Ariane [Observatoire astronomique and CNRS UMR 7550, Universite de Strasbourg, Strasbourg (France); Chandar, Rupali [Department of Physics and Astronomy, University of Toledo, Toledo, OH (United States); Whitmore, Bradley C., E-mail: morgan.fouesneau@astro.u-strasbg.fr [Space Telescope Science Institute, Baltimore, MD (United States)

2012-05-01T23:59:59.000Z

4

ELEMENTAL ABUNDANCE RATIOS IN STARS OF THE OUTER GALACTIC DISK. IV. A NEW SAMPLE OF OPEN CLUSTERS  

SciTech Connect

We present radial velocities and chemical abundances for nine stars in the old, distant open clusters Be18, Be21, Be22, Be32, and PWM4. For Be18 and PWM4, these are the first chemical abundance measurements. Combining our data with literature results produces a compilation of some 68 chemical abundance measurements in 49 unique clusters. For this combined sample, we study the chemical abundances of open clusters as a function of distance, age, and metallicity. We confirm that the metallicity gradient in the outer disk is flatter than the gradient in the vicinity of the solar neighborhood. We also confirm that the open clusters in the outer disk are metal-poor with enhancements in the ratios [{alpha}/Fe] and perhaps [Eu/Fe]. All elements show negligible or small trends between [X/Fe] and distance (<0.02 dex kpc{sup -1}), but for some elements, there is a hint that the local (R{sub GC} < 13 kpc) and distant (R{sub GC} > 13 kpc) samples may have different trends with distance. There is no evidence for significant abundance trends versus age (<0.04 dex Gyr{sup -1}). We measure the linear relation between [X/Fe] and metallicity, [Fe/H], and find that the scatter about the mean trend is comparable to the measurement uncertainties. Comparison with solar neighborhood field giants shows that the open clusters share similar abundance ratios [X/Fe] at a given metallicity. While the flattening of the metallicity gradient and enhanced [{alpha}/Fe] ratios in the outer disk suggest a chemical enrichment history different from that of the solar neighborhood, we echo the sentiments expressed by Friel et al. that definitive conclusions await homogeneous analyses of larger samples of stars in larger numbers of clusters. Arguably, our understanding of the evolution of the outer disk from open clusters is currently limited by systematic abundance differences between various studies.

Yong, David [Research School of Astronomy and Astrophysics, Australian National University, Weston, ACT 2611 (Australia); Carney, Bruce W. [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599-3255 (United States); Friel, Eileen D., E-mail: yong@mso.anu.edu.au, E-mail: bruce@physics.unc.edu, E-mail: efriel@indiana.edu [Department of Astronomy, Indiana University, Bloomington, IN 47405 (United States)

2012-10-01T23:59:59.000Z

5

JOINT ANALYSIS OF CLUSTER OBSERVATIONS. II. CHANDRA/XMM-NEWTON X-RAY AND WEAK LENSING SCALING RELATIONS FOR A SAMPLE OF 50 RICH CLUSTERS OF GALAXIES  

SciTech Connect

We present a study of multiwavelength X-ray and weak lensing scaling relations for a sample of 50 clusters of galaxies. Our analysis combines Chandra and XMM-Newton data using an energy-dependent cross-calibration. After considering a number of scaling relations, we find that gas mass is the most robust estimator of weak lensing mass, yielding 15% {+-} 6% intrinsic scatter at r{sub 500}{sup WL} (the pseudo-pressure Y{sub X} yields a consistent scatter of 22% {+-} 5%). The scatter does not change when measured within a fixed physical radius of 1 Mpc. Clusters with small brightest cluster galaxy (BCG) to X-ray peak offsets constitute a very regular population whose members have the same gas mass fractions and whose even smaller (<10%) deviations from regularity can be ascribed to line of sight geometrical effects alone. Cool-core clusters, while a somewhat different population, also show the same (<10%) scatter in the gas mass-lensing mass relation. There is a good correlation and a hint of bimodality in the plane defined by BCG offset and central entropy (or central cooling time). The pseudo-pressure Y{sub X} does not discriminate between the more relaxed and less relaxed populations, making it perhaps the more even-handed mass proxy for surveys. Overall, hydrostatic masses underestimate weak lensing masses by 10% on the average at r{sub 500}{sup WL}; but cool-core clusters are consistent with no bias, while non-cool-core clusters have a large and constant 15%-20% bias between r{sub 2500}{sup WL} and r{sub 500}{sup WL}, in agreement with N-body simulations incorporating unthermalized gas. For non-cool-core clusters, the bias correlates well with BCG ellipticity. We also examine centroid shift variance and power ratios to quantify substructure; these quantities do not correlate with residuals in the scaling relations. Individual clusters have for the most part forgotten the source of their departures from self-similarity.

Mahdavi, Andisheh [Department of Physics and Astronomy, San Francisco State University, San Francisco, CA 94131 (United States); Hoekstra, Henk [Leiden Observatory, Leiden University, Niels Bohrweg 2, NL-2333 CA Leiden (Netherlands); Babul, Arif; Bildfell, Chris [Department of Physics and Astronomy, University of Victoria, Victoria, BC V8W 3P6 (Canada); Jeltema, Tesla [Santa Cruz Institute for Particle Physics, UC Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Henry, J. Patrick [Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

2013-04-20T23:59:59.000Z

6

Mass Models and Sunyaev-Zeldovich Effect Predictions for a Flux Limited Sample of 22 Nearby X-Ray Clusters  

E-Print Network (OSTI)

We define a 90% complete, volume-limited sample of 31 z<0.1 x-ray clusters and present a systematic analysis of public ROSAT PSPC data on 22 of these objects. Our efforts are undertaken in support of the Penn/OVRO SZE survey, and to this end we present predictions for the inverse Compton optical depth towards all 22 of these clusters. We have performed detailed Monte Carlo simulations to understand the effects of the cluster profile uncertainties on the SZE predictions given the OVRO 5.5-meter telescope beam and switching patterns; we find that the profile uncertainties are one of the least significant components of our error budget for SZE-based distance measurements. We also present baryonic masses and baryon mass fractions derived under the assumption of hydrostatic equilibrium for these 22 clusters. The mean baryonic mass fraction within R_500 \\sim 500 h^-1 kpc is (7.02 \\pm 0.28) x 10^-2 h^-3/2, or (19.8 \\pm 0.8) x 10^-2 for h=0.5. We confirm the Allen et al. (1993) claim of an excess absorbing column density towards Abell 478, but do not find similar anomalies in the other 21 clusters in our sample. We also find some evidence for an excess of soft counts in the ROSAT PSPC data. A measurement of H_o using these models and OVRO SZE determinations will be presented in a second paper.

Brian S. Mason; Steven T. Myers

1999-10-25T23:59:59.000Z

7

BINARY FREQUENCIES IN A SAMPLE OF GLOBULAR CLUSTERS. I. METHODOLOGY AND INITIAL RESULTS  

SciTech Connect

Binary stars are thought to be a controlling factor in globular cluster evolution, since they can heat the environmental stars by converting their binding energy to kinetic energy during dynamical interactions. Through such interaction, the binaries determine the time until core collapse. To test predictions of this model, we have determined binary fractions for 35 clusters. Here we present our methodology with a representative globular cluster NGC 4590. We use Hubble Space Telescope archival Advanced Camera for Surveys data in the F606W and F814W bands and apply point-spread-function-fitting photometry to obtain high quality color-magnitude diagrams. We formulate the star superposition effect as a Poisson probability distribution function, with parameters optimized through Monte Carlo simulations. A model-independent binary fraction of (6.2 {+-} 0.3)% is obtained by counting stars that extend to the red side of the residual color distribution after accounting for the photometric errors and the star superposition effect. A model-dependent binary fraction is obtained by constructing models with a known binary fraction and an assumed binary mass-ratio distribution function. This leads to a binary fraction range of 6.8%-10.8%, depending on the assumed shape to the binary mass-ratio distribution, with the best fit occurring for a binary distribution that favors low mass ratios (and higher binary fractions). We also represent the method for radial analysis of the binary fraction in the representative case of NGC 6981, which shows a decreasing trend for the binary fraction toward the outside, consistent with theoretical predictions for the dynamical effect on the binary fraction.

Ji Jun; Bregman, Joel N., E-mail: jijun@umich.edu, E-mail: jbregman@umich.edu [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States)

2013-05-10T23:59:59.000Z

8

Employing post-DEA Cross-evaluation and Cluster Analysis in a Sample of Greek NHS Hospitals  

Science Conference Proceedings (OSTI)

To increase Data Envelopment Analysis (DEA) discrimination of efficient Decision Making Units (DMUs), by complementing "self-evaluated" efficiencies with "peer-evaluated" cross-efficiencies and, based on these results, to classify the DMUs using cluster ... Keywords: Benchmarking, Cluster analysis, Cross-efficiency, Data envelopment analysis, Hospital

Angeliki Flokou; Nick Kontodimopoulos; Dimitris Niakas

2011-10-01T23:59:59.000Z

9

The SEGUE Stellar Parameter Pipeline. IV. Validation with an Extended Sample of Galactic Globular and Open Clusters  

Science Conference Proceedings (OSTI)

Spectroscopic and photometric data for likely member stars of five Galactic globular clusters (M 3, M 53, M 71, M 92, and NGC 5053) and three open clusters (M 35, NGC 2158, and NGC 6791) are processed by the current version of the SEGUE Stellar Parameter Pipeline (SSPP), in order to determine estimates of metallicities and radial velocities for the clusters. These results are then compared to values from the literature. We find that the mean metallicity () and mean radial velocity (hRVi) estimates for each cluster are almost all within 2{sigma} of the adopted literature values; most are within 1{sigma}. We also demonstrate that the new version of the SSPP achieves small, but noteworthy, improvements in estimates at the extrema of the cluster metallicity range, as compared to a previous version of the pipeline software. These results provide additional confidence in the application of the SSPP for studies of the abundances and kinematics of stellar populations in the Galaxy.

Smolinski, Jason P.; Beers, Timothy C.; Lee, Young Sun; /Michigan State U. /Michigan State U., JINA; An, Deokkeun; /Ewha Women's U., Seoul; Bickerton, Steven J.; /Princeton U., Astrophys. Sci. Dept.; Johnson, Jennifer A.; /Ohio State U., Dept. Astron.; Loomis, Craig P.; /Princeton U., Astrophys. Sci. Dept.; Rockosi, Constance M.; /Lick Observ.; Sivarani, Thirupathi; /Bangalore, Indian Inst. Astrophys.; Yanny, Brian; /Fermilab

2010-08-01T23:59:59.000Z

10

THE SEGUE STELLAR PARAMETER PIPELINE. IV. VALIDATION WITH AN EXTENDED SAMPLE OF GALACTIC GLOBULAR AND OPEN CLUSTERS  

Science Conference Proceedings (OSTI)

Spectroscopic and photometric data for likely member stars of five Galactic globular clusters (M3, M53, M71, M92, and NGC 5053) and three open clusters (M35, NGC 2158, and NGC 6791) are processed by the current version of the SEGUE Stellar Parameter Pipeline (SSPP), in order to determine estimates of metallicities and radial velocities (RVs) for the clusters. These results are then compared to values from the literature. We find that the mean metallicity (([Fe/H])) and mean radial velocity ((RV)) estimates for each cluster are almost all within 2{sigma} of the adopted literature values; most are within 1{sigma}. We also demonstrate that the new version of the SSPP achieves small, but noteworthy, improvements in ([Fe/H]) estimates at the extrema of the cluster metallicity range, as compared to a previous version of the pipeline software. These results provide additional confidence in the application of the SSPP for studies of the abundances and kinematics of stellar populations in the Galaxy.

Smolinski, Jason P.; Lee, Young Sun; Beers, Timothy C. [Department of Physics and Astronomy and JINA (Joint Institute for Nuclear Astrophysics), Michigan State University, East Lansing, MI 48824 (United States); An, Deokkeun [Department of Science Education, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Bickerton, Steven J.; Loomis, Craig P. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Johnson, Jennifer A. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Rockosi, Constance M. [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Sivarani, Thirupathi [IIAP: Indian Institute of Astrophysics, II Block, Koramangala, Bangalore 560 034 (India); Yanny, Brian, E-mail: smolin19@msu.edu, E-mail: lee@pa.msu.edu, E-mail: beers@pa.msu.edu, E-mail: deokkeun@ewha.ac.kr, E-mail: bick@astro.princeton.edu, E-mail: cloomis@astro.princeton.edu, E-mail: jaj@astronomy.ohio-state.edu, E-mail: crockosi@ucolick.org, E-mail: sivarani@iiap.res.in, E-mail: yanny@fnal.gov [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States)

2011-03-15T23:59:59.000Z

11

The SEGUE Stellar Parameter Pipeline. IV. Validation with an Extended Sample of Galactic Globular and Open Clusters  

SciTech Connect

Spectroscopic and photometric data for likely member stars of five Galactic globular clusters (M 3, M 53, M 71, M 92, and NGC 5053) and three open clusters (M 35, NGC 2158, and NGC 6791) are processed by the current version of the SEGUE Stellar Parameter Pipeline (SSPP), in order to determine estimates of metallicities and radial velocities for the clusters. These results are then compared to values from the literature. We find that the mean metallicity (<[Fe/H]>) and mean radial velocity (hRVi) estimates for each cluster are almost all within 2{sigma} of the adopted literature values; most are within 1{sigma}. We also demonstrate that the new version of the SSPP achieves small, but noteworthy, improvements in <[Fe/H]> estimates at the extrema of the cluster metallicity range, as compared to a previous version of the pipeline software. These results provide additional confidence in the application of the SSPP for studies of the abundances and kinematics of stellar populations in the Galaxy.

Smolinski, Jason P.; Beers, Timothy C.; Lee, Young Sun; /Michigan State U. /Michigan State U., JINA; An, Deokkeun; /Ewha Women's U., Seoul; Bickerton, Steven J.; /Princeton U., Astrophys. Sci. Dept.; Johnson, Jennifer A.; /Ohio State U., Dept. Astron.; Loomis, Craig P.; /Princeton U., Astrophys. Sci. Dept.; Rockosi, Constance M.; /Lick Observ.; Sivarani, Thirupathi; /Bangalore, Indian Inst. Astrophys.; Yanny, Brian; /Fermilab

2010-08-01T23:59:59.000Z

12

Cluster Statistics  

NLE Websites -- All DOE Office Websites (Extended Search)

Statistics Cluster Statistics Genepool Cluster Utilization Genepool Usage by Group Process Accounting Data (houseHunter) Genepool Memory Heatmaps Genepool Time Heatmaps UGE...

13

clustering free  

Science Conference Proceedings (OSTI)

NIST. clustering free. (definition). Definition: When a collision resolution scheme spreads out entries in a hash table. ...

2013-11-18T23:59:59.000Z

14

Simultaneous clustering: a survey  

Science Conference Proceedings (OSTI)

Although most of the clustering literature focuses on onesided clustering algorithms, simultaneous clustering has recently gained attention as a powerful tool that allows to circumvent some limitations of classical clustering approach. Simultaneous clustering ... Keywords: biclusters, block clustering, simultaneous clustering

Malika Charrad; Mohamed Ben Ahmed

2011-06-01T23:59:59.000Z

15

Sampling community structure  

Science Conference Proceedings (OSTI)

We propose a novel method, based on concepts from expander graphs, to sample communities in networks. We show that our sampling method, unlike previous techniques, produces subgraphs representative of community structure in the original network. These ... Keywords: clustering, community detection, complex networks, graphs, sampling, social networks

Arun S. Maiya; Tanya Y. Berger-Wolf

2010-04-01T23:59:59.000Z

16

CLUSTER CHEMISTRY  

E-Print Network (OSTI)

Advanced Inorganic Chemistry, 11 Wiley Huetterties and C. M.Submitted to the Journal of Organometallic ChemistryCLUSTER CHEMISTRY Earl L. Muetterties TWO-WEEK LOAN COPY May

Muetterties, Earl L.

2013-01-01T23:59:59.000Z

17

Cluster generator  

DOE Patents (OSTI)

Described herein is an apparatus and a method for producing atom clusters based on a gas discharge within a hollow cathode. The hollow cathode includes one or more walls. The one or more walls define a sputtering chamber within the hollow cathode and include a material to be sputtered. A hollow anode is positioned at an end of the sputtering chamber, and atom clusters are formed when a gas discharge is generated between the hollow anode and the hollow cathode.

Donchev, Todor I. (Urbana, IL); Petrov, Ivan G. (Champaign, IL)

2011-05-31T23:59:59.000Z

18

Data clustering: a review  

Science Conference Proceedings (OSTI)

Clustering is the unsupervised classification of patterns (observations, data items, or feature vectors) into groups (clusters). The clustering problem has been addressed in many contexts and by researchers in many disciplines; this reflects its broad ... Keywords: cluster analysis, clustering applications, exploratory data analysis, incremental clustering, similarity indices, unsupervised learning

A. K. Jain; M. N. Murty; P. J. Flynn

1999-09-01T23:59:59.000Z

19

ComputerCluster ? FCW  

NLE Websites -- All DOE Office Websites (Extended Search)

CNMS Computer Cluster This page describes the CNMS Computational Cluster, how to access it, and how to use it. (16 August 2010) N.B. The latest block of the CNMS Computer Cluster...

20

Cluster Compatibility Mode  

NLE Websites -- All DOE Office Websites (Extended Search)

Cluster Compatibility Mode Cluster Compatibility Mode Edison compute nodes run a stripped down Linux operating system called Compute Node Linux (CNL). Some standard Linux services,...

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Sampling diffusive transition paths  

SciTech Connect

We address the problem of sampling double-ended diffusive paths. The ensemble of paths is expressed using a symmetric version of the Onsager-Machlup formula, which only requires evaluation of the force field and which, upon direct time discretization, gives rise to a symmetric integrator that is accurate to second order. Efficiently sampling this ensemble requires avoiding the well-known stiffness problem associated with sampling infinitesimal Brownian increments of the path, as well as a different type of stiffness associated with sampling the coarse features of long paths. The fine-features sampling stiffness is eliminated with the use of the fast sampling algorithm (FSA), and the coarse-feature sampling stiffness is avoided by introducing the sliding and sampling (S&S) algorithm. A key feature of the S&S algorithm is that it enables massively parallel computers to sample diffusive trajectories that are long in time. We use the algorithm to sample the transition path ensemble for the structural interconversion of the 38-atom Lennard-Jones cluster at low temperature.

F. Miller III, Thomas; Predescu, Cristian

2006-10-12T23:59:59.000Z

22

GALAXY CLUSTER ENVIRONMENTS OF RADIO SOURCES  

SciTech Connect

Using the Sloan Digital Sky Survey (SDSS) and the Faint Images of the Radio Sky at Twenty Centimeters (FIRST) catalogs, we examined the optical environments around double-lobed radio sources. Previous studies have shown that multi-component radio sources exhibiting some degree of bending between components are likely to be found in galaxy clusters. Often this radio emission is associated with a cD-type galaxy at the center of a cluster. We cross-correlated the SDSS and FIRST catalogs and measured the richness of the cluster environments surrounding both bent and straight multi-component radio sources. This led to the discovery and classification of a large number of galaxy clusters out to a redshift of z {approx} 0.5. We divided our sample into smaller subgroups based on their optical and radio properties. We find that FR I radio sources are more likely to be found in galaxy clusters than FR II sources. Further, we find that bent radio sources are more often found in galaxy clusters than non-bent radio sources. We also examined the environments around single-component radio sources and find that single-component radio sources are less likely to be associated with galaxy clusters than extended, multi-component radio sources. Bent, visually selected sources are found in clusters or rich groups {approx}78% of the time. Those without optical hosts in SDSS are likely associated with clusters at even higher redshifts, most with redshifts of z>0.7.

Wing, Joshua D.; Blanton, Elizabeth L., E-mail: jwing@bu.edu [Astronomy Department and Institute for Astrophysical Research, Boston University, Boston, MA 02215 (United States)

2011-03-15T23:59:59.000Z

23

CLUSTERING BY HYPERBOLIC SMOOTHING Cluster analysis ...  

E-Print Network (OSTI)

Jul 31, 2007 ... The numerical experiments were car- ried out on a Pentium IV PC ..... Design of hybrids for minimum sum-of-squares clustering problem.

24

Sampling – Soil  

INL has developed a method for sampling soil to determine the presence of extremely fine particles such as absorbents.

25

Anthrax Sampling  

NLE Websites -- All DOE Office Websites (Extended Search)

Anthrax Anthrax Sampling and Decontamination: Technology Trade-Offs Phillip N. Price, Kristina Hamachi, Jennifer McWilliams, and Michael D. Sohn Environmental Energy Technologies Division Lawrence Berkeley National Laboratory Berkeley CA 94720 September 12, 2008 This work was supported by the Office of Science, Office of High Energy Physics, Homeland Security under the U.S. Department of Energy under Contract No. DE-AC02-05CH1123. Contents 1 Executive Summary 3 1.1 How much sampling is needed to decide if a building is safe? . . . . . . . 3 1.1.1 Sampling Nomogram . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2 How many characterization samples should be taken? . . . . . . . . . . . 7 1.3 What decontamination method should be used? . . . . . . . . . . . . . . . 7 1.4 Post-decontamination sampling . . . . . . . . . . . . . . . . . . . . . . . . 8 1.5 What are rules of thumb for cost and effort? . . . . . . . . . . . .

26

A penalized fuzzy clustering algorithm  

Science Conference Proceedings (OSTI)

In this paper, we propose a penalized inter-cluster separation (PICS) fuzzy clustering algorithm by adding a penalty term to the inter-cluster separation (ICS) algorithm. Numerical comparisons are made for several fuzzy clustering algorithms according ... Keywords: fuzzy c-means (FCM), fuzzy clustering, image segmentation, inter-cluster separation (ICS), magnetic resonance image (MRI), penalized ICS

Miin-Shen Yang; Wen-Liang Hung; Chia-Hsuan Chang

2006-12-01T23:59:59.000Z

27

Sampling box  

DOE Patents (OSTI)

An air sampling box that uses a slidable filter tray and a removable filter cartridge to allow for the easy replacement of a filter which catches radioactive particles is disclosed.

Phillips, Terrance D. (617 Chestnut Ct., Aiken, SC 29803); Johnson, Craig (100 Midland Rd., Oak Ridge, TN 37831-0895)

2000-01-01T23:59:59.000Z

28

Document clustering with committees  

E-Print Network (OSTI)

Document clustering is useful in many information retrieval tasks: document browsing, organization and viewing of retrieval results, generation of Yahoo-like hierarchies of documents, etc. The general goal of clustering is to group data elements such that the intra-group similarities are high and the inter-group similarities are low. We present a clustering algorithm called CBC (Clustering By Committee) that is shown to produce higher quality clusters in document clustering tasks as compared to several well known clustering algorithms. It initially discovers a set of tight clusters (high intra-group similarity), called committees, that are well scattered in the similarity space (low inter-group similarity). The union of the committees is but a subset of all elements. The algorithm proceeds by assigning elements to their most similar committee. Evaluating cluster quality has always been a difficult task. We present a new evaluation methodology that is based on the editing distance between output clusters and manually constructed classes (the answer key). This evaluation measure is more intuitive and easier to interpret than previous evaluation measures.

Patrick Pantel; Dekang Lin

2002-01-01T23:59:59.000Z

29

Electron: Cluster interactions  

SciTech Connect

Beam depletion spectroscopy has been used to measure absolute total inelastic electron-sodium cluster collision cross sections in the energy range from E {approximately} 0.1 to E {approximately} 6 eV. The investigation focused on the closed shell clusters Na{sub 8}, Na{sub 20}, Na{sub 40}. The measured cross sections show an increase for the lowest collision energies where electron attachment is the primary scattering channel. The electron attachment cross section can be understood in terms of Langevin scattering, connecting this measurement with the polarizability of the cluster. For energies above the dissociation energy the measured electron-cluster cross section is energy independent, thus defining an electron-cluster interaction range. This interaction range increases with the cluster size.

Scheidemann, A.A. [Washington Univ., Seattle, WA (United States). Dept. of Chemistry; Kresin, V.V. [Lawrence Livermore National Lab., CA (United States); Knight, W.D. [California Univ., Berkeley, CA (United States). Dept. of Physics

1994-02-01T23:59:59.000Z

30

NREL: Process Development and Integration Laboratory - Silicon Cluster Tool  

NLE Websites -- All DOE Office Websites (Extended Search)

Silicon Cluster Tool Capabilities Silicon Cluster Tool Capabilities Photo of a cylindrical metal chamber surrounded by numerous other smaller cylindrical or rectangular chambers. Each tool has several flanges and is typically held within a metal frame or rack. A computer is on a table in front of a cabinet of electronic equipment. Silicon cluster tool in the Process Development and Integration Laboratory. The Silicon cluster tool within the Process Development and Integration Laboratory is a 10-port cluster tool designed by the National Renewable Energy Laboratory (NREL) and manufactured by MVSystems. It handles standard 157-mm x 157-mm samples introduced into the central 10-6 torr vacuum chamber via a load lock. From there, a robotic arm moves samples from one chamber to another within the cluster tool. Contact Qi Wang for more

31

A WISE VIEW OF STAR FORMATION IN LOCAL GALAXY CLUSTERS  

SciTech Connect

We present results from a systematic study of star formation in local galaxy clusters using 22 {mu}m data from the Wide-field Infrared Survey Explorer (WISE). The 69 systems in our sample are drawn from the Cluster Infall Regions Survey, and all have robust mass determinations. The all-sky WISE data enable us to quantify the amount of star formation, as traced by 22 {mu}m, as a function of radius well beyond R{sub 200}, and investigate the dependence of total star formation rate upon cluster mass. We find that the fraction of star-forming galaxies increases with cluster radius but remains below the field value even at 3R{sub 200}. We also find that there is no strong correlation between the mass-normalized total specific star formation rate and cluster mass, indicating that the mass of the host cluster does not strongly influence the total star formation rate of cluster members.

Chung, Sun Mi; Gonzalez, Anthony H. [Department of Astronomy, University of Florida, Gainesville, FL 32611-2055 (United States); Eisenhardt, Peter R.; Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Stanford, Spencer A. [Department of Physics, University of California, Davis, CA 95616 (United States); Brodwin, Mark [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Jarrett, Thomas, E-mail: schung@astro.ufl.edu [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States)

2011-12-10T23:59:59.000Z

32

HOW TO FIND YOUNG MASSIVE CLUSTER PROGENITORS  

SciTech Connect

We propose that bound, young massive stellar clusters form from dense clouds that have escape speeds greater than the sound speed in photo-ionized gas. In these clumps, radiative feedback in the form of gas ionization is bottled up, enabling star formation to proceed to sufficiently high efficiency so that the resulting star cluster remains bound even after gas removal. We estimate the observable properties of the massive proto-clusters (MPCs) for existing Galactic plane surveys and suggest how they may be sought in recent and upcoming extragalactic observations. These surveys will potentially provide a significant sample of MPC candidates that will allow us to better understand extreme star-formation and massive cluster formation in the Local Universe.

Bressert, E.; Longmore, S.; Testi, L. [European Southern Observatory, Karl Schwarzschild Str. 2, D-85748 Garching bei Muenchen (Germany); Ginsburg, A.; Bally, J.; Battersby, C. [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States)

2012-10-20T23:59:59.000Z

33

Siting technologies for large wind turbine clusters  

DOE Green Energy (OSTI)

Site selection for large wind turbine clusters requires thorough documentation of the wind characteristics at the site, because of the influence these characteristics will have on the economics, operations, and service life of the wind turbines. The wind prospecting strategy can be used by a utility to determine specific locations for each wind turbine in a cluster of 10 to 50 or more machines. The key to site selection is knowing what and where to measure. Siting techniques to be used at the various stages of the wind-prospecting strategy are discussed. These techniques help determine where to measure. What to measure at a site is still a moot question. Suggestions are made on what data are needed at what sampling rates. These are based on the assumption that until further experience in siting large clusters of wind turbines is in hand, thorough documentation of wind characteristics affecting machine and cluster output characteristics, operation strategies, and service life are necessary.

Hiester, T.R.; Pennell, W.T.

1979-11-01T23:59:59.000Z

34

AN UPDATED CATALOG OF M33 CLUSTERS AND CANDIDATES: UBVRI PHOTOMETRY AND SOME STATISTICAL RESULTS  

SciTech Connect

We present UBVRI photometry for 392 star clusters and candidates in the field of M33, which are selected from the most recent star cluster catalog. In this catalog, the authors listed star clusters' parameters such as cluster positions, magnitudes, colors in the UBVRIJHK{sub s} filters, and so on. However, a large fraction of objects in this catalog do not have previously published photometry. Photometry is performed using archival images from the Local Group Galaxies Survey, which covers 0.8 deg{sup 2} along the major axis of M33. Detailed comparisons show that, in general, our photometry is consistent with previous measurements. Positions (right ascension and declination) for some clusters are corrected here. Combined with previous literature, ours constitute a large sample of M33 star clusters. Based on this cluster sample, we present some statistical results: none of the youngest M33 clusters ({approx}10{sup 7} yr) have masses approaching 10{sup 5} M{sub Sun} ; roughly half the star clusters are consistent with the 10{sup 4}-10{sup 5} M{sub Sun} mass models; the continuous distribution of star clusters along the model line indicates that M33 star clusters have been formed continuously from the epoch of the first star cluster formation until recent times; and there are {approx}50 star clusters which are overlapped with the Galactic globular clusters on the color-color diagram, and these clusters are old globular cluster candidates in M33.

Ma Jun, E-mail: majun@nao.cas.cn [National Astronomical Observatories, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing 100012 (China)

2012-08-15T23:59:59.000Z

35

Cluster mass function in mixed models  

E-Print Network (OSTI)

We study the cluster mass function in mixed dark matter (MDM) models, using two COBE normalized simulations with Omega_h = 0.26 and n=1.2, and Omega_h = 0.14 and n = 1.05, both with 2 massive nu's (MDM1 and MDM2, respectively). For the sake of comparison, we also simulate a CDM model with spectral index n=0.8 (TCDM), also COBE normalized. We argue that, in our non--hydro simulations, where CDM particles describe both actual CDM and baryons, the galaxy distribution traces CDM particles. Therefore, we use them to define clusters and their velocities to work out cluster masses. As CDM particles are more clustered than HDM and therefore have, in average, greater velocities, this leads to significant differences from PS predictions. Such predictions agree with simulations if both HDM and CDM are used to define clusters. Clusters defined through CDM in MDM models, instead, are less numerous than PS estimates, by a factor ~0.3, at the low mass end; the factor becomes \\~0.6-0.8, depending on the mix, on intermediate mass scales (~4-5, h^-1 10^14 Msun) and almost vanishes on the high mass end. Therefore: (i) MDM models expected to overproduce clusters over intermediate scales are viable; (ii) the greater reduction factor at small scales agrees with the observational data dependence on the cluster mass M (which, however, may be partially due to sample incompleteness); (iii) the higher spectral normalization is felt at large scales, where MDM models produce more objects (hence, large clusters) than CDM. MDM1 even exceeds Donahue et al. (1998) findings, while MDM2 is consistent with them. (abridged)

A. Gardini; S. A. Bonometto; G. Murante

1999-05-21T23:59:59.000Z

36

X-RAY BINARIES AND STAR CLUSTERS IN THE ANTENNAE: OPTICAL CLUSTER COUNTERPARTS  

SciTech Connect

We compare the locations of 82 X-ray binaries (XRBs) detected in the merging Antennae galaxies by Zezas et al., based on observations taken with the Chandra X-Ray Observatory, with a catalog of optically selected star clusters presented by Whitmore et al., based on observations taken with the Hubble Space Telescope. Within the 2{sigma} positional uncertainty of Almost-Equal-To 0.''8, we find 22 XRBs are coincident with star clusters, where only two to three chance coincidences are expected. The ages of the clusters were estimated by comparing their UBVI, H{alpha} colors with predictions from stellar evolutionary models. We find that 14 of the 22 coincident XRBs (64%) are hosted by star clusters with ages of Almost-Equal-To 6 Myr or less. All of the very young host clusters are fairly massive and have M {approx}> 3 Multiplication-Sign 10{sup 4} M {sub Sun }, with many having masses M Almost-Equal-To 10{sup 5} M {sub Sun }. Five of the XRBs are hosted by young clusters with ages {tau} Almost-Equal-To 10-100 Myr, while three are hosted by intermediate-age clusters with {tau} Almost-Equal-To 100-300 Myr. Based on the results from recent N-body simulations, which suggest that black holes are far more likely to be retained within their parent clusters than neutron stars, we suggest that our sample consists primarily of black hole binaries with different ages.

Rangelov, Blagoy; Chandar, Rupali [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States); Prestwich, Andrea [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Whitmore, Bradley C., E-mail: blagoy.rangelov@gmail.com [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

2012-10-20T23:59:59.000Z

37

Cold cluster ferromagnetism  

SciTech Connect

We examine the magnetic moment distribution of ferromagnetic clusters under conditions where the magnetic moment is aligned with the internal cluster axis. Analytic expressions are obtained for the moment distribution and the adiabatic average moment induced in low fields. The result differs from the low-field Langevin function by a factor 2/3.

Bertsch, G.F. [Washington Univ., Seattle, WA (United States). Inst. for Nuclear Theory; Yabana, K. [Niigata Univ. (Japan). Dept. of Physics

1993-12-31T23:59:59.000Z

38

Cool Cluster Correctly Correlated  

Science Conference Proceedings (OSTI)

Atomic clusters are unique objects, which occupy an intermediate position between atoms and condensed matter systems. For a long time it was thought that physical and chemical properties of atomic dusters monotonically change with increasing size of the cluster from a single atom to a condensed matter system. However, recently it has become clear that many properties of atomic clusters can change drastically with the size of the clusters. Because physical and chemical properties of clusters can be adjusted simply by changing the cluster's size, different applications of atomic clusters were proposed. One example is the catalytic activity of clusters of specific sizes in different chemical reactions. Another example is a potential application of atomic clusters in microelectronics, where their band gaps can be adjusted by simply changing cluster sizes. In recent years significant advances in experimental techniques allow one to synthesize and study atomic clusters of specified sizes. However, the interpretation of the results is often difficult. The theoretical methods are frequently used to help in interpretation of complex experimental data. Most of the theoretical approaches have been based on empirical or semiempirical methods. These methods allow one to study large and small dusters using the same approximations. However, since empirical and semiempirical methods rely on simple models with many parameters, it is often difficult to estimate the quantitative and even qualitative accuracy of the results. On the other hand, because of significant advances in quantum chemical methods and computer capabilities, it is now possible to do high quality ab-initio calculations not only on systems of few atoms but on clusters of practical interest as well. In addition to accurate results for specific clusters, such methods can be used for benchmarking of different empirical and semiempirical approaches. The atomic clusters studied in this work contain from a few atoms to tens of atoms. Therefore, they are quantum objects. Some qualitative information about the geometries of such clusters can be obtained with classical empirical methods, for example geometry optimization using an empirical Lennard-Jones potential. However, to predict their accurate geometries and other physical and chemical properties it is necessary to solve a Schroedinger equation. If one is not interested in dynamics of clusters it is enough to solve the stationary (time-independent) Schroedinger equation (H{Phi}=E{Phi}). This equation represents a multidimensional eigenvalue problem. The solution of the Schroedinger equation is a set of eigenvectors (wave functions) and their eigenvalues (energies). The lowest energy solution (wave function) corresponds to the ground state of the cluster. The other solutions correspond to excited states. The wave function gives all information about the quantum state of the cluster and can be used to calculate different physical and chemical properties, such as photoelectron, X-ray, NMR, EPR spectra, dipole moment, polarizability etc. The dimensionality of the Schroedinger equation is determined by the number of particles (nuclei and electrons) in the cluster. The analytic solution is only known for a two particle problem. In order to solve the equation for clusters of interest it is necessary to make a number of approximations and use numerical methods.

Sergey Aleksandrovich Varganov

2005-12-17T23:59:59.000Z

39

Document clustering methods, document cluster label disambiguation methods, document clustering apparatuses, and articles of manufacture  

DOE Patents (OSTI)

Document clustering methods, document cluster label disambiguation methods, document clustering apparatuses, and articles of manufacture are described. In one aspect, a document clustering method includes providing a document set comprising a plurality of documents, providing a cluster comprising a subset of the documents of the document set, using a plurality of terms of the documents, providing a cluster label indicative of subject matter content of the documents of the cluster, wherein the cluster label comprises a plurality of word senses, and selecting one of the word senses of the cluster label.

Sanfilippo, Antonio (Richland, WA); Calapristi, Augustin J. (West Richland, WA); Crow, Vernon L. (Richland, WA); Hetzler, Elizabeth G. (Kennewick, WA); Turner, Alan E. (Kennewick, WA)

2009-12-22T23:59:59.000Z

40

Heating Rate Profiles in Galaxy Clusters  

E-Print Network (OSTI)

In recent years evidence has accumulated suggesting that the gas in galaxy clusters is heated by non-gravitational processes. Here we calculate the heating rates required to maintain a physically motived mass flow rate, in a sample of seven galaxy clusters. We employ the spectroscopic mass deposition rates as an observational input along with temperature and density data for each cluster. On energetic grounds we find that thermal conduction could provide the necessary heating for A2199, Perseus, A1795 and A478. However, the suppression factor, of the clasical Spitzer value, is a different function of radius for each cluster. Based on the observations of plasma bubbles we also calculate the duty cycles for each AGN, in the absence of thermal conduction, which can provide the required energy input. With the exception of Hydra-A it appears that each of the other AGNs in our sample require duty cycles of roughly $10^{6}-10^{7}$ yrs to provide their steady-state heating requirements. If these duty cycles are unrealistic, this may imply that many galaxy clusters must be heated by very powerful Hydra-A type events interspersed between more frequent smaller-scale outbursts. The suppression factors for the thermal conductivity required for combined heating by AGN and thermal conduction are generally acceptable. However, these suppression factors still require `fine-tuning` of the thermal conductivity as a function of radius. As a consequence of this work we present the AGN duty cycle as a cooling flow diagnostic.

Edward C. D. Pope; Georgi Pavlovski; Christian R. Kaiser; Hans Fangohr

2006-01-05T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Matrix Approximation and Projective Clustering via Iterative Sampling  

E-Print Network (OSTI)

We present two new results for the problem of approximating a given real m by n matrix A by a rank-k matrix D, where k < min{m, n}, so as to minimize ||A-D||_F^2. It is known that bysampling O(k/eps) rows of the matrix, ...

Rademacher, Luis

2005-03-29T23:59:59.000Z

42

Cluster Sampling and Its Applications in Image Analysis  

E-Print Network (OSTI)

i.e. likelihood in Bayesian inference. In this paper, weto general Bayesian inference on graphs. Especially we focusprobabilities in many Bayesian inference tasks. x m u mi x n

Adrian Barbu; Song-Chun Zhu

2011-01-01T23:59:59.000Z

43

Cluster Sampling and Its Applications in Image Analysis  

E-Print Network (OSTI)

i.e. likelihood in Bayesian inference. In this paper, weto general Bayesian inference on graphs. Especially we focusprobabilities in many Bayesian inference tasks. x m u mi x n

Barbu, Adrian; Zhu, Song-Chun

2004-01-01T23:59:59.000Z

44

Ab initio Monte Carlo investigation of small lithium clusters.  

Science Conference Proceedings (OSTI)

Structural and thermal properties of small lithium clusters are studied using ab initio-based Monte Carlo simulations. The ab initio scheme uses a Hartree-Fock/density functional treatment of the electronic structure combined with a jump-walking Monte Carlo sampling of nuclear configurations. Structural forms of Li{sub 8} and Li{sub 9}{sup +} clusters are obtained and their thermal properties analyzed in terms of probability distributions of the cluster potential energy, average potential energy and configurational heat capacity all considered as a function of the cluster temperature. Details of the gradual evolution with temperature of the structural forms sampled are examined. Temperatures characterizing the onset of structural changes and isomer coexistence are identified for both clusters.

Srinivas, S.

1999-06-16T23:59:59.000Z

45

Partition selection approach for hierarchical clustering based on clustering ensemble  

Science Conference Proceedings (OSTI)

Hierarchical clustering algorithms are widely used in many fields of investigation. They provide a hierarchy of partitions of the same dataset. However, in many practical problems, the selection of a representative level (partition) in the hierarchy ... Keywords: cluster validity index, clustering ensemble, hierarchical clustering, partition selection

Sandro Vega-Pons; José Ruiz-Shulcloper

2010-11-01T23:59:59.000Z

46

Clusters and entrepreneurship  

E-Print Network (OSTI)

This article examines the role of regional clusters in regional entrepreneurship. We focus on the distinct influences of convergence and agglomeration on growth in the number of start-up firms as well as in employment in ...

Delgado, Mercedes

47

Exploring Beowulf clusters  

Science Conference Proceedings (OSTI)

Beowulf clusters provide the computational power of parallel programming at minimal cost, making this technology available to small colleges and individual labs. In this paper, we explore the construction and programming of four distinct varieties of ...

Marsha Meredith; Teresa Carrigan; James Brockman; Timothy Cloninger; Jaroslav Privoznik; Jeffery Williams

2003-04-01T23:59:59.000Z

48

THE PANCHROMATIC HUBBLE ANDROMEDA TREASURY. III. MEASURING AGES AND MASSES OF PARTIALLY RESOLVED STELLAR CLUSTERS  

Science Conference Proceedings (OSTI)

The apparent age and mass of a stellar cluster can be strongly affected by stochastic sampling of the stellar initial mass function (IMF), when inferred from the integrated color of low-mass clusters ({approx}light of the fainter, more numerous unresolved stars can be analyzed separately. When comparing the light from the less luminous cluster members to models of unresolved light, more accurate age estimates can be obtained than when analyzing the integrated light from the entire cluster under the assumption that the IMF is fully populated. We show the success of this technique first using simulated clusters, and then with a stellar cluster in M31. This method represents one way of accounting for the discrete, stochastic sampling of the stellar IMF in less massive clusters and can be leveraged in studies of clusters throughout the Local Group and other nearby galaxies.

Beerman, Lori C.; Johnson, L. Clifton; Fouesneau, Morgan; Dalcanton, Julianne J.; Weisz, Daniel R.; Williams, Ben F. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Seth, Anil C. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Bell, Eric F. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Bianchi, Luciana C. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Caldwell, Nelson [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Dolphin, Andrew E. [Raytheon Company, 1151 East Hermans Road, Tucson, AZ 85756 (United States); Gouliermis, Dimitrios A. [Zentrum fuer Astronomie, Institut fuer Theoretische Astrophysik, Universitaet Heidelberg, Albert-Ueberle-Strasse 2, D-69120 Heidelberg (Germany); Kalirai, Jason S. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Larsen, Soren S. [Department of Astrophysics, IMAPP, Radboud University Nijmegen, P.O. Box 9010, NL-6500 GL Nijmegen (Netherlands); Melbourne, Jason L. [Caltech Optical Observatories, Division of Physics, Mathematics and Astronomy, Mail Stop 301-17, California Institute of Technology, Pasadena, CA 91125 (United States); Rix, Hans-Walter [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Skillman, Evan D., E-mail: beermalc@astro.washington.edu [Department of Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States)

2012-12-01T23:59:59.000Z

49

Substructure in the Coma Cluster: Giants vs Dwarfs  

E-Print Network (OSTI)

The processes that form and shape galaxy clusters, such as infall, mergers and dynamical relaxation, tend to generate distinguishable differences between the distributions of a cluster's giant and dwarf galaxies. Thus the dynamics of dwarf galaxies in a cluster can provide valuable insights into its dynamical history. With this in mind, we look for differences between the spatial and velocity distributions of giant (b18) galaxies in the Coma cluster. Our redshift sample contains new measurements from the 2dF and WYFFOS spectrographs, making it more complete at faint magnitudes than any previously studied sample of Coma galaxies. It includes 745 cluster members - 452 giants and 293 dwarfs. We find that the line-of-sight velocity distribution of the giants is significantly non-Gaussian, but not that for the dwarfs. A battery of statistical tests of both the spatial and localised velocity distributions of the galaxies in our sample finds no strong evidence for differences between the giant and dwarf populations. These results rule out the cluster as a whole having moved significantly towards equipartition, and they are consistent with the cluster having formed via mergers between dynamically-relaxed subclusters.

Scott A. Edwards; Matthew Colless; Terry J. Bridges; Dave Carter; Bahram Mobasher; Bianca M. Poggianti

2001-11-02T23:59:59.000Z

50

Clusters in Light Nuclei  

E-Print Network (OSTI)

A great deal of research work has been undertaken in the alpha-clustering study since the pioneering discovery, half a century ago, of 12C+12C molecular resonances. Our knowledge of the field of the physics of nuclear molecules has increased considerably and nuclear clustering remains one of the most fruitful domains of nuclear physics, facing some of the greatest challenges and opportunities in the years ahead. In this work, the occurence of "exotic" shapes in light N=Z alpha-like nuclei is investigated. Various approaches of superdeformed and hyperdeformed bands associated with quasimolecular resonant structures are presented. Results on clustering aspects are also discussed for light neutron-rich Oxygen isotopes.

C. Beck; P. Papka; A. Sanchez i Zafra; S. Thummerer; F. Azaiez; P. Bednarczyk; S. Courtin; D. Curien; O. Dorvaux; A. Goasduff; D. Lebhertz; A. Nourreddine; M. Rousseau; M. -D. Salsac; W. von Oertzen; B. Gebauer; C. Wheldon; Tz. Kokalova; G. Efimov; V. Zherebchevsky; Ch. Schulz; H. G. Bohlen; D. Kamanin; G. de Angelis; A. Gadea; S. Lenzi; D. R. Napoli; S. Szilner; M. Milin; W. N. Catford; D. G. Jenkins; G. Royer

2010-11-15T23:59:59.000Z

51

Efficiently Clustering Documents with Committees  

E-Print Network (OSTI)

Abstract. The general goal of clustering is to group data elements such that the intragroup similarities are high and the inter-group similarities are low. We present a clustering algorithm called CBC (Clustering By Committee) that is shown to produce higher quality clusters in document clustering tasks as compared to several well known clustering algorithms. It initially discovers a set of tight clusters (high intra-group similarity), called committees, that are well scattered in the similarity space (low inter-group similarity). The union of the committees is but a subset of all elements. The algorithm proceeds by assigning elements to their most similar committee. Evaluating cluster quality has always been a difficult task. We present a new evaluation methodology based on the editing distance between output clusters and manually constructed classes (the answer key). This evaluation measure is more intuitive and easier to interpret than previous evaluation measures. 1

Patrick Pantel; Dekang Lin

2002-01-01T23:59:59.000Z

52

Four-stage computational technology with adaptive numerical methods for computational aerodynamics  

Science Conference Proceedings (OSTI)

Computational aerodynamics is a key technology in aircraft design which is ahead of physical experiment and complements it. Of course all three components of computational modeling are actively developed: mathematical models of real aerodynamic processes

2012-01-01T23:59:59.000Z

53

Charged Metallic Clusters  

Science Conference Proceedings (OSTI)

Usually in Nuclear Physics the minimum of the liquid drop model (LDM) energy occurs at a mass asymmetry which is different from the minimum of shell correction. Charged metallic clusters are ideal emitters of singly ionized trimers because both LDM and shell correction are reaching a minimum for the same mass asymmetry corresponding to the emission of a charged particle with two delocalized electrons. Maximum dissociation energy (Q-value) is obtained for metallic clusters with high surface tension and low Wigner-Seitz radius (transition metals). The Q-values for spheroidal shapes are much larger than for hemispheroids.

Poenaru, D. N.; Gherghescu, R. A. [Horia Hulubei National Institute of Physics and Nuclear Engineering (IFIN-HH), Bucharest-Magurele (Romania); Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe University, Frankfurt am Main (Germany); Solov'yov, A. V.; Greiner, W. [Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe University, Frankfurt am Main (Germany)

2009-12-03T23:59:59.000Z

54

Nuclear Cluster Physics  

Science Conference Proceedings (OSTI)

Predictive power of theory needs good models and accurate calculation methods to solve the Schroedinger equations of the systems concerned. We present some examples of successful predictions based on the nuclear cluster models of light nuclei and hypernuclei and on the calculation methods that have been developed by Kyushu group.

Kamimura, Masayasu [RIKEN Nishina Center, RIKEN, Wako 351-0198 (Japan); Department of Physics, Kyushu University, Fukuoka 812-8581 (Japan)

2011-05-06T23:59:59.000Z

55

FUEL ROD CLUSTERS  

DOE Patents (OSTI)

A cluster of nuclear fuel rods and a tubular casing therefor through which a coolant flows in heat-exchange contact with the fuel rods is described. The fuel rcds are held in the casing by virtue of the compressive force exerted between longitudinal ribs of the fuel rcds and internal ribs of the casing or the internal surfaces thereof.

Schultz, A.B.

1959-08-01T23:59:59.000Z

56

WISE-cluster: clustering e-commerce search engines automatically  

Science Conference Proceedings (OSTI)

In this paper, we propose a new approach to automatically clustering e-commerce search engines (ESEs) on the Web such that ESEs in the same cluster sell similar products. This allows an e-commerce metasearch engine (comparison shopping system) to be ... Keywords: document clustering, search engine categorization

2004-11-01T23:59:59.000Z

57

No evidence for mass segregation in young clusters  

E-Print Network (OSTI)

Aims. We investigate the validity of mass segregation indicators commonly used in the analysis of young stellar clusters. Methods. We simulate observations by constructing synthetic seeing limited images of a 1000 massive clusters (10^4 Msun) with a standard IMF and a King density distribution function. Results. We find that commonly used indicators are highly sensitive to sample incompleteness in observational data, and that radial completeness determinations do not provide satisfactory corrections, rendering the studies of radial properties highly uncertain. On the other hand, we find that under certain conditions, the global completeness can be estimated accurately, allowing for the correction of the global luminosity and mass functions of the cluster. Conclusions. We argue that there is currently no observational evidence for mass segregation in young compact clusters since there is not a robust way to differentiate between true mass segregation and sample incompleteness effects. Caution should then be ex...

Ascenso, J; Lago, M T V T

2008-01-01T23:59:59.000Z

58

Ensemble Clustering for Result Diversification  

Science Conference Proceedings (OSTI)

Page 1. Ensemble Clustering for Result Diversification Dong Nguyen Human Media Interaction University of Twente d.nguyen@utwente.nl ...

2013-02-12T23:59:59.000Z

59

The Assembly of Galaxy Clusters  

SciTech Connect

We study the formation of fifty-three galaxy cluster-size dark matter halos (M = 10{sup 14.0-14.76} M{sub {circle_dot}}) formed within a pair of cosmological {Lambda}CDM N-body simulations, and track the accretion histories of cluster subhalos with masses large enough to host {approx} 0.1L{sub *} galaxies. By associating subhalos with cluster galaxies, we find the majority of galaxies in clusters experience no 'pre-processing' in the group environment prior to their accretion into the cluster. On average, {approx} 70% of cluster galaxies fall into the cluster potential directly from the field, with no luminous companions in their host halos at the time of accretion; and less than {approx} 12% are accreted as members of groups with five or more galaxies. Moreover, we find that cluster galaxies are significantly less likely to have experienced a merger in the recent past ({approx}< 6 Gyr) than a field halo of the same mass. These results suggest that local, cluster processes like ram-pressure stripping, galaxy harassment, or strangulation play the dominant role in explaining the difference between cluster and field populations at a fixed stellar mass; and that pre-evolution or past merging in the group environment is of secondary importance for setting cluster galaxy properties for most clusters. The accretion times for z = 0 cluster members are quite extended, with {approx} 20% incorporated into the cluster halo more than 7 Gyr ago and {approx} 20% within the last 2 Gyr. By comparing the observed morphological fractions in cluster and field populations, we estimate an approximate time-scale for late-type to early-type transformation within the cluster environment to be {approx} 6 Gyr.

Berrier, Joel C.; Stewart, Kyle R.; Bullock, James S.; Purcell, Chris W.; Barton, Elizabeth J.; Wechsler, Risa H.

2008-05-16T23:59:59.000Z

60

The Coincidence of Nuclear Star Clusters and Active Galactic Nuclei  

E-Print Network (OSTI)

We study galaxies that host both nuclear star clusters and active galactic nuclei (AGN) implying the presence of a massive black hole. We select a sample of 176 galaxies with previously detected nuclear star clusters that range from ellipticals to late-type spirals. We search for AGN in this sample using optical spectroscopy and archival radio and X-ray data. We find galaxies of all Hubble types and with a wide range of masses (10^9-11 solar masses) hosting both AGN and nuclear star clusters. From the optical spectra, we classify 10% of the galaxies as AGN and an additional 15% as composite, indicating a mix of AGN and star-formation spectra. The fraction of nucleated galaxies with AGN increases strongly as a function of galaxy and nuclear star cluster mass. For galaxies with both a NC and a black hole, we find that the masses of these two objects are quite similar. However, non-detections of black holes in Local Group nuclear star clusters show that not all clusters host black holes of similar masses. We discuss the implications of our results for the formation of nuclear star clusters and massive black holes.

Anil Seth; Marcel Agueros; Duane Lee; Antara Basu-Zych

2008-01-02T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

The Assembly of Galaxy Clusters  

Science Conference Proceedings (OSTI)

We study the formation of fifty-three galaxy cluster-size dark matter halos (M = 10{sup 14.0-14.76} M{sub {circle_dot}}) formed within a pair of cosmological {Lambda}CDM N-body simulations, and track the accretion histories of cluster subhalos with masses large enough to host {approx} 0.1L{sub *} galaxies. By associating subhalos with cluster galaxies, we find the majority of galaxies in clusters experience no 'pre-processing' in the group environment prior to their accretion into the cluster. On average, {approx} 70% of cluster galaxies fall into the cluster potential directly from the field, with no luminous companions in their host halos at the time of accretion; and less than {approx} 12% are accreted as members of groups with five or more galaxies. Moreover, we find that cluster galaxies are significantly less likely to have experienced a merger in the recent past ({approx}ram-pressure stripping, galaxy harassment, or strangulation play the dominant role in explaining the difference between cluster and field populations at a fixed stellar mass; and that pre-evolution or past merging in the group environment is of secondary importance for setting cluster galaxy properties for most clusters. The accretion times for z = 0 cluster members are quite extended, with {approx} 20% incorporated into the cluster halo more than 7 Gyr ago and {approx} 20% within the last 2 Gyr. By comparing the observed morphological fractions in cluster and field populations, we estimate an approximate time-scale for late-type to early-type transformation within the cluster environment to be {approx} 6 Gyr.

Berrier, Joel C.; Stewart, Kyle R.; Bullock, James S.; Purcell, Chris W.; Barton, Elizabeth J.; Wechsler, Risa H.

2008-05-16T23:59:59.000Z

62

Cluster-Impact Fusion  

Science Conference Proceedings (OSTI)

This report considers the theoretical interpretation of cluster-impact fusion (CIF). The proton energy spectrum of CIF shows it to be hot fusion on a microscopic atomic scale. The temperature of the reaction can be determined by the Doppler-like broadening of the 3.025 MeV proton line. The spectrum also indicates that the high temperature results from a one-dimensional rather than a three-dimensional velocity distribution.

1992-05-01T23:59:59.000Z

63

Globular Cluster Distance Determinations  

E-Print Network (OSTI)

The present status of the distance scale to Galactic globular clusters is reviewed. Six distance determination techniques which are deemed to be most reliable are discussed in depth. These different techniques are used to calibrate the absolute magnitude of the RR Lyrae stars. The various calibrations fall into three groups. Main sequence fitting using Hipparcos parallaxes, theoretical HB models and the RR Lyrae in the LMC all favor a bright calibration, implying a `long' globular cluster distance scale. White dwarf fitting and the astrometric distances yield a somewhat fainter RR Lyrae calibration, while the statistical parallax solution yields faint RR Lyrae stars implying a `short' distance scale to globular clusters. Various secondary distance indicators discussed all favor the long distance scale. The `long' and `short' distance scales differ by (0.31+/-0.16) mag. Averaging together all of the different distance determinations yields Mv(RR) = (0.23+/-0.04)([Fe/H] + 1.6) + (0.56+/-0.12) mag.

Brian Chaboyer

1998-08-19T23:59:59.000Z

64

White Dwarfs in Globular Clusters  

E-Print Network (OSTI)

We review empirical and theoretical findings concerning white dwarfs in Galactic globular clusters. Since their detection is a critical issue we describe in detail the various efforts to find white dwarfs in globular clusters. We then outline the advantages of using cluster white dwarfs to investigate the formation and evolution of white dwarfs and concentrate on evolutionary channels that appear to be unique to globular clusters. We also discuss the usefulness of globular cluster white dwarfs to provide independent information on the distances and ages of globular clusters, information that is very important far beyond the immediate field of white dwarf research. Finally, we mention possible future avenues concerning globular cluster white dwarfs, like the study of strange quark matter or plasma neutrinos.

S. Moehler; G. Bono

2008-06-27T23:59:59.000Z

65

A New Method of Source Rock Prediction Based on Q Cluster in YB Region, Northern Sichuan Basin  

Science Conference Proceedings (OSTI)

On the basis of clustering theory, Q cluster is applied to predict source rocks. Distance coefficient and similarity coefficient are calculated, and the shortest distance method is used to analyze the oil shale samples. Then, a prediction map of the ... Keywords: Cluster, Distance coefficient, Similarity coefficient, Shortest distance method, source rock prediction

Peng Bo, Li Guorong, Zhao Yong, Zhao Yingquan, Hu Jingjing, Liao Tai-Ping

2013-06-01T23:59:59.000Z

66

Globular Cluster Ages and the Formation of the Galactic Halo  

E-Print Network (OSTI)

Main sequence turnoff magnitudes from the recent set of Yale isochrones (Chaboyer \\ea 1995) have been combined with a variety of relations for the absolute magnitude of RR Lyr stars (\\mvrr) to calibrate age as a function of the difference in magnitude between the main sequence turn-off and the horizontal branch (\\dv). A best estimate for the calibration of \\mvrr is derived from a survey of the current literature: $\\mvrr = 0.20 \\feh + 0.98$. This estimate, together with other calibrations (with slopes ranging from 0.15 to 0.30) has been used to derive \\dv ages for 43 Galactic globular clusters. Independent of the choice of \\mvrr, there is no strong evidence for an age-Galacto\\-centric distance relationship among the 43 globular clusters. However, an age-metallicity relation exists, with the metal-poor clusters being the oldest. A study of the age distribution reveals that an age range of 5 Gyr exists among the bulk of the globular clusters. In addition, about 10\\% of the sample are substantially younger, and including them in the analysis increases the age range to 9 Gyr. Once again, these statements are independent of the \\mvrr ~relation. Evidence for age being the second parameter governing horizontal branch morphology is found by comparing the average \\dv ~age of the second parameter clusters to the normal clusters. The second parameter clusters are found to be on average 2 - 3 Gyr younger than the other clusters, which is consistent with age being the second parameter. These results suggest that globular clusters were formed over an extended period of time, with progressively more metal-rich globular clusters ($\\feh \\ga -1.7$) being formed at later times.

Brian Chaboyer; P. Demarque; Ata Sarajedini

1995-09-12T23:59:59.000Z

67

Measuring Cluster Relaxedness  

SciTech Connect

When is a dark matter halo 'relaxed'? In our efforts to understand the structure of the universe, dark matter simulations have provided essential grounds for theoretical predictions. These simulations provide a wealth of ways of parameterizing and measuring the features of astronomical objects. It is these measurements on which we base comparisons of our world and our attempts to re-create it. One of the essential questions dark matter simulations help address is how dark matter halos evolve. How does one characterize different states of that evolution? The focus of this project is identifying cluster relaxedness and how it relates to the internal structure of the halo. A dark matter simulation consists of an N-body simulation which takes an initial set of positions and velocities of the dark matter particles and evolves them under the influence of gravity [6]. Though scientists have so far not been able to detect dark matter particles, the information from these simulations is still valuable especially given the relationship between dark matter halos and galaxy clusters. Galaxies sit within dark matter halos and recent evidence points to filaments of dark matter forming the framework on which galaxy clusters grow [7]. A dark matter halo is a collapsed group of gravitationally bound dark matter particles. Subsets of bound particles form subhalos or substructures. The dark matter simulation is carried out over time - with decreasing redshift (z) or increasing scale factor (a = 1/1+z ). (Thus, z = 0 or a = 1.0 is present-day.) The merger history of a halo can be represented pictorally by a merger tree. A major merger event occurs when a structure joins the main halo with the mass ratio between it and the main halo being above a certain threshold. These events mark important points in the halo's evolution. And it is at these events that one hopes, and perhaps is more likely, to relate measures of relaxedness to this mass accretion. Cluster relaxedness is not a well-defined concept. Rather a set of qualities are defined that one expects a 'relaxed' cluster to have. One expects a relaxed halo to have a roughly isotropic density distribution. Most of the particles should be part of the main halo rather than bound in substructures. Taking into account kinematic information of the halo, one does not expect a proportion of the particles energy in kinetic energy that goes far beyond virial equilibrium. With our measures of cluster relaxedness, we want to investigate its relationship to these major merger events. We'll first look at how measurements of different aspects of relaxedness relate to each other and to other aspects of a halo's internal structure. We'll then look at how these measurements behave in response to major mergers.

Moreland, Blythe; /Michigan U. /SLAC

2012-08-24T23:59:59.000Z

68

Are Earthquake Magnitudes Clustered?  

Science Conference Proceedings (OSTI)

The question of earthquake predictability is a long-standing and important challenge. Recent results [Phys. Rev. Lett. 98, 098501 (2007); ibid.100, 038501 (2008)] have suggested that earthquake magnitudes are clustered, thus indicating that they are not independent in contrast to what is typically assumed. Here, we present evidence that the observed magnitude correlations are to a large extent, if not entirely, an artifact due to the incompleteness of earthquake catalogs and the well-known modified Omori law. The latter leads to variations in the frequency-magnitude distribution if the distribution is constrained to those earthquakes that are close in space and time to the directly following event.

Davidsen, Joern; Green, Adam [Complexity Science Group, Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4 (Canada)

2011-03-11T23:59:59.000Z

69

Cooling flows, central galaxy--cluster alignments, X-ray absorption and dust  

E-Print Network (OSTI)

We present the analysis of pointed ROSAT PSPC observations of five of the most luminous, intermediate redshift ($0.1 cooling flows. The alignment between CCGs and their host clusters has been investigated. For those clusters with cooling flows, the position angles of the X-ray emission from the clusters and the optical emission from the CCGs agrees within 5 degrees. For the one probable non-cooling flow cluster in the sample, Abell 2208, the alignment is significantly poorer. We examine the evidence for intrinsic X-ray absorption in the clusters. The X-ray spectra for Abell 1068 and Abell 1664 show that the cooling flows in these clusters are intrinsically absorbed by equivalent hydrogen column densities $\\geq 10^{21} atom cm$^{-2}$. The optical spectra of the CCGs in these clusters exhibit substantial intrinsic reddening, at levels consistent with the X-ray absorption results if standard dust to gas ratios are assumed.

S. W. Allen; A. C. Fabian; A. C. Edge; H. Bohringer; D. A. White

1995-03-28T23:59:59.000Z

70

Performance Analysis of Enhanced Clustering Algorithm for Gene Expression Data  

E-Print Network (OSTI)

Microarrays are made it possible to simultaneously monitor the expression profiles of thousands of genes under various experimental conditions. It is used to identify the co-expressed genes in specific cells or tissues that are actively used to make proteins. This method is used to analysis the gene expression, an important task in bioinformatics research. Cluster analysis of gene expression data has proved to be a useful tool for identifying co-expressed genes, biologically relevant groupings of genes and samples. In this paper we applied K-Means with Automatic Generations of Merge Factor for ISODATA- AGMFI. Though AGMFI has been applied for clustering of Gene Expression Data, this proposed Enhanced Automatic Generations of Merge Factor for ISODATA- EAGMFI Algorithms overcome the drawbacks of AGMFI in terms of specifying the optimal number of clusters and initialization of good cluster centroids. Experimental results on Gene Expression Data show that the proposed EAGMFI algorithms could identify compact clus...

Chandrasekhar, T; Elayaraja, E

2011-01-01T23:59:59.000Z

71

SIZES OF GALACTIC GLOBULAR CLUSTERS  

SciTech Connect

A study is made of deviations from the mean power-law relationship between the Galactocentric distances and the half-light radii of Galactic globular clusters. Surprisingly, deviations from the mean R{sub h} versus R{sub gc} relationship do not appear to correlate with cluster luminosity, cluster metallicity, or horizontal-branch morphology. Differences in orbit shape are found to contribute to the scatter in the R{sub h} versus R{sub gc} relationship of Galactic globular clusters.

Van den Bergh, Sidney, E-mail: sidney.vandenbergh@nrc-cnrc.gc.ca [Dominion Astrophysical Observatory, Herzberg Institute of Astrophysics, National Research Council of Canada, 5071 West Saanich Road, Victoria, BC, V9E 2E7 (Canada)

2012-02-20T23:59:59.000Z

72

Two-Cluster Distribution Functions  

NLE Websites -- All DOE Office Websites (Extended Search)

Cluster Distribution Functions New New: Green's function Monte Carlo results We have computed momentum distributions and configuration space overlaps in a number of systems,...

73

Variability Study of EHB Stars in the Globular Cluster NGC 6752  

E-Print Network (OSTI)

We present the results of a search for variable stars in the central part of the globular cluster NGC 6752. The monitored sample included 160 BHB and 107 EHB stars, respectively. A total of 17 variables were detected of which 14 are new identifications. Five variables are BHB/EHB stars. We report also on identification of a detached eclipsing binary being likely a member of the cluster. Moreover, we detected an outburst of a dwarf nova located in the cluster core.

J. Kaluzny; I. B. Thompson

2007-12-21T23:59:59.000Z

74

Acceptance sampling methods for sample results verification  

SciTech Connect

This report proposes a statistical sampling method for use during the sample results verification portion of the validation of data packages. In particular, this method was derived specifically for the validation of data packages for metals target analyte analysis performed under United States Environmental Protection Agency Contract Laboratory Program protocols, where sample results verification can be quite time consuming. The purpose of such a statistical method is to provide options in addition to the ``all or nothing`` options that currently exist for sample results verification. The proposed method allows the amount of data validated during the sample results verification process to be based on a balance between risks and the cost of inspection.

Jesse, C.A.

1993-06-01T23:59:59.000Z

75

Substructure in the Coma Cluster Giants vs Dwarfs  

E-Print Network (OSTI)

The processes that form and shape galaxy clusters, such as infall, mergers and dynamical relaxation, tend to generate distinguishable differences between the distributions of a cluster's giant and dwarf galaxies. Thus the dynamics of dwarf galaxies in a cluster can provide valuable insights into its dynamical history. With this in mind, we look for differences between the spatial and velocity distributions of giant (b18) galaxies in the Coma cluster. Our redshift sample contains new measurements from the 2dF and WYFFOS spectrographs, making it more complete at faint magnitudes than any previously studied sample of Coma galaxies. It includes 745 cluster members - 452 giants and 293 dwarfs. We find that the line-of-sight velocity distribution of the giants is significantly non-Gaussian, but not that for the dwarfs. A battery of statistical tests of both the spatial and localised velocity distributions of the galaxies in our sample finds no strong evidence for differences between the giant and dwarf populations....

Edwards, S A; Bridges, T J; Carter, D; Mobasher, B; Poggianti, B M; Edwards, Scott A.; Colless, Matthew; Bridges, Terry J.; Carter, Dave; Mobasher, Bahram; Poggianti, Bianca M.

2001-01-01T23:59:59.000Z

76

Query clustering using user logs  

Science Conference Proceedings (OSTI)

Query clustering is a process used to discover frequently asked questions or most popular topics on a search engine. This process is crucial for search engines based on question-answering. Because of the short lengths of queries, approaches based on ... Keywords: Query clustering, search engine, user log, web data mining

2002-01-01T23:59:59.000Z

77

Clustering in massive data sets  

Science Conference Proceedings (OSTI)

We review the time and storage costs of search and clustering algorithms. We exemplify these, based on case-studies in astronomy, information retrieval, visual user interfaces, chemical databases, and other areas. Theoretical results developed as far ... Keywords: clustering, massive data sets

Fionn Murtagh

2002-01-01T23:59:59.000Z

78

Antibody-gold cluster conjugates  

DOE Patents (OSTI)

Antibody- or antibody fragment-gold cluster conjugates are shown wherein the conjugate size can be about 5.0 nm. Methods and reagents are disclosed in which antibodies or Fab' fragments thereof are covalently bound to a stable cluster of gold atoms. 2 figs.

Hainfeld, J.F.

1988-06-28T23:59:59.000Z

79

Sample Preparation Laboratory Training - Course 204 | Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

Sample Preparation Laboratory Training - Course 204 Who Should Attend This course is mandatory for: SLAC employees and non-employees who need unescorted access to SSRL or LCLS...

80

Discovering cardholders' payment-patterns based on clustering analysis  

Science Conference Proceedings (OSTI)

This paper sampled approximately 9.3 million entries of data, concerning payments from 300,000 credit card customers over the past two years of Bank A in Taiwan. By applying data mining techniques to decipher customers' behavior and perform risk analysis, ... Keywords: Clustering algorithms, Credit card, Data mining

Chien-Chou Shih; Ding-An Chiang; Yi-jen Hu; Chun-Chi Chen

2011-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Pose-Based Clustering in Action Sequences  

Science Conference Proceedings (OSTI)

A method is presented for automatically extracting key frames from an image sequence. The sequence is divided into clusters of frames with similar appearance, and the most central frame in each cluster defines a key frame. Clustering is done using ...

Gareth Loy; Josephine Sullivan; Stefan Carlsson

2003-10-01T23:59:59.000Z

82

On challenges in evaluating malware clustering  

Science Conference Proceedings (OSTI)

Malware clustering and classification are important tools that enable analysts to prioritize their malware analysis efforts. The recent emergence of fully automated methods for malware clustering and classification that report high accuracy suggests ... Keywords: malware clustering and classification, plagiarism detection

Peng Li; Limin Liu; Debin Gao; Michael K. Reiter

2010-09-01T23:59:59.000Z

83

Cosmological Constraints from the SDSS maxBCG Cluster Catalog  

Science Conference Proceedings (OSTI)

We use the abundance and weak lensing mass measurements of the SDSS maxBCG cluster catalog to simultaneously constrain cosmology and the richness-mass relation of the clusters. Assuming a flat {Lambda}CDM cosmology, we find {sigma}{sub 8}({Omega}{sub m}/0.25){sup 0.41} = 0.832 {+-} 0.033 after marginalization over all systematics. In common with previous studies, our error budget is dominated by systematic uncertainties, the primary two being the absolute mass scale of the weak lensing masses of the maxBCG clusters, and uncertainty in the scatter of the richness-mass relation. Our constraints are fully consistent with the WMAP five-year data, and in a joint analysis we find {sigma}{sub 8} = 0.807 {+-} 0.020 and {Omega}{sub m} = 0.265 {+-} 0.016, an improvement of nearly a factor of two relative to WMAP5 alone. Our results are also in excellent agreement with and comparable in precision to the latest cosmological constraints from X-ray cluster abundances. The remarkable consistency among these results demonstrates that cluster abundance constraints are not only tight but also robust, and highlight the power of optically-selected cluster samples to produce precision constraints on cosmological parameters.

Rozo, Eduardo; /CCAPP; Wechsler, Risa H.; /KIPAC, Menlo Park /SLAC; Rykoff, Eli S.; /UC, Santa Barbara; Annis, James T.; /Fermilab; Becker, Matthew R.; /Chicago U. /KICP, Chicago; Evrard, August E.; /Michigan U. /Michigan U., MCTP; Frieman, Joshua A.; /Fermilab /KICP, Chicago /Chicago U.; Hansen, Sarah M.; /UC, Santa Cruz; Hao, Jia; /Michigan U.; Johnston, David E.; /Northwestern U.; Koester, Benjamin P.; /KICP, Chicago /Chicago U.; McKay, Timothy A.; /Michigan U. /Michigan U., MCTP; Sheldon, Erin S.; /Brookhaven; Weinberg, David H.; /CCAPP /Ohio State U.

2009-08-03T23:59:59.000Z

84

Additive Manufacturing Cluster Strategy | ornl.gov  

NLE Websites -- All DOE Office Websites (Extended Search)

Additive Manufacturing Cluster Strategy SHARE Additive Manufacturing Cluster Strategy As the nation's premier research laboratory, ORNL is one of the world's most capable resources...

85

Dust cluster explosion  

Science Conference Proceedings (OSTI)

A model for the dust cluster explosion where micron/sub-micron sized particles are accelerated at the expense of plasma thermal energy, in the afterglow phase of a complex plasma discharge is proposed. The model is tested by molecular dynamics simulations of dust particles in a confining potential. The nature of the explosion (caused by switching off the discharge) and the concomitant dust acceleration is found to depend critically on the pressure of the background neutral gas. At low gas pressure, the explosion is due to unshielded Coulomb repulsion between dust particles and yields maximum acceleration, while in the high pressure regime it is due to shielded Yukawa repulsion and yields much feebler acceleration. These results are in agreement with experimental findings. Our simulations also confirm a recently proposed electrostatic (ES) isothermal scaling relation, P{sub E}{proportional_to}V{sub d}{sup -2} (where P{sub E} is the ES pressure of the dust particles and V{sub d} is the confining volume).

Saxena, Vikrant [School of Mathematics and Physics, Queen's University Belfast, Belfast, Northern Ireland (United Kingdom); Institute for Plasma Research, Bhat, Gandhinagar (India); Avinash, K. [Department of Physics and Astrophysics, University of Delhi, New Delhi (India); Sen, A. [Institute for Plasma Research, Bhat, Gandhinagar (India)

2012-09-15T23:59:59.000Z

86

STAR CLUSTERS IN THE TIDAL TAILS OF INTERACTING GALAXIES: CLUSTER POPULATIONS ACROSS A VARIETY OF TAIL ENVIRONMENTS  

Science Conference Proceedings (OSTI)

We have searched for compact stellar structures within 17 tidal tails in 13 different interacting galaxies using F606W- and F814W-band images from the Wide Field Planetary Camera 2 on the Hubble Space Telescope. The sample of tidal tails includes a diverse population of optical properties, merging galaxy mass ratios, H I content, and ages. Combining our tail sample with Knierman et al., we find evidence of star clusters formed in situ with M{sub V} < -8.5 and V - I < 2.0 in 10 of 23 tidal tails; we are able to identify cluster candidates to M{sub V} = -6.5 in the closest tails. Three tails offer clear examples of 'beads on a string' star formation morphology in V - I color maps. Two tails present both tidal dwarf galaxy candidates and cluster candidates. Statistical diagnostics indicate that clusters in tidal tails may be drawn from the same power-law luminosity functions (with logarithmic slopes {approx}-2 to -2.5) found in quiescent spiral galaxies and interiors of interacting systems. We find that the tail regions with the largest number of observable clusters are relatively young ({approx}<250 Myr old) and bright (V {approx}< 24 mag arcsec{sup -2}), probably attributed to the strong bursts of star formation in interacting systems soon after periapse. Otherwise, we find no statistical difference between cluster-rich and cluster-poor tails in terms of many observable characteristics, though this analysis suffers from complex, unresolved gas dynamics and projection effects.

Mullan, B.; Konstantopoulos, I. S.; Lee, K. H.; Charlton, J. C.; Gronwall, C.; Hunsberger, S.; Palma, C. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16803 (United States); Kepley, A. A.; Johnson, K. E. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Knierman, K. [School of Earth and Space Exploration, Bateman Physical Sciences Center, Arizona State University, F-wing Room 686, Tempe, AZ 85287-1404 (United States); Bastian, N. [School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom); Chandar, R. [Department of Physics and Astronomy, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 (United States); Durrell, P. R. [Department of Physics and Astronomy, Youngstown State University, Youngstown, OH 44555 (United States); Elmegreen, D. [Department of Physics and Astronomy, Vassar College, Box 745, Poughkeepsie, NY 12604 (United States); English, J. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Gallagher, S. C. [Department of Physics and Astronomy, University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 3K7 (Canada); Hibbard, J. E. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States); Maybhate, A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Trancho, G. [Gemini Observatory, Casilla 603, Colina el Pino S/N, La Serena (Chile); Vacca, W. D., E-mail: mullan@astro.psu.edu [Stratospheric Observatory for Infrared Astronomy/Universities Space Research Association, NASA Ames Research Center, MS 144-2, Moffett Field, CA 94035 (United States)

2011-04-20T23:59:59.000Z

87

CCD uvbyHbeta Photometry in Clusters: I. The Open Cluster Standard, IC 4651  

E-Print Network (OSTI)

CCD photometry of the intermediate-age open cluster, IC 4651, on the uvbyHbeta system is presented and analyzed. By using a combination of the information from the color-magnitude diagram (CMD) and the color-color diagrams, a sample of 98 highly probable main sequence cluster members with high photometric accuracy is isolated. From this sample, adopting the intrinsic color relation of Olsen (1988), E(b-y) = 0.062 +/- 0.003 and [Fe/H] = +0.077 +/- 0.012, where the errors quoted are the standard errors of the mean and refer to the internal errors alone. Use of the Nissen (1988) intrinsic color relation produces E(b-y) = 0.071 and [Fe/H] = +0.115. Adopting the lower reddening, a direct main-sequence fit to the Hyades with (m-M) = 3.33 leads to (m-M) = 10.15, while isochrones with convective overshoot and zeroed to the Hyades produce an age of 1.7 +/- 0.1 Gyr, with an excellent match to the morphology of the turnoff. The higher reddening produces (m-M) = 10.3 and an age lower by 0.1 Gyr. Comparison with the CMD of NGC 3680 shows that the two clusters have virtually identical morphology which, in combination with their similar compositions, produces identical ages. Coincidentally, the shifts in the CMD necessary to superpose the two clusters require that the apparent moduli of IC 4651 and NGC 3680 be the same, while E(b-y)(4651) = E(b-y)(3680) + 0.04.

B. J. Anthony-Twarog; B. A. Twarog

1999-12-28T23:59:59.000Z

88

On the origin and acceleration of cosmic rays: Cooling flow clusters and AGN hosts  

E-Print Network (OSTI)

We are looking for radio `relics' and `halos' in an X-ray selected sample of clusters of galaxies. These radio features are not a product of the Active Galactic Nuclei (AGN)-mechanism, but more likely are associated with past cluster merger events. AGN hosts of cooling flow clusters contain particle bubbles that show non-thermal radio emission. These bubbles could explain the presence of radio relics and halos if they can restrict cosmic rays efficiently. Intracluster magnetic fields and cluster environments can reveal the acceleration mechanisms of cosmic rays. Using radio/X-ray data and analytical methods we examine three AGN hosts out of our 70 clusters, namely Hercules A, 3C310 and 3C388. We found that none of these clusters contain relics and/or halos.

Gizani, Nectaria A B

2011-01-01T23:59:59.000Z

89

September 2004 Water Sampling  

Office of Legacy Management (LM)

Sampling at the Sampling at the Shirley Basin South, Wyoming, Disposal Site September 2013 LMS/SBS/S00613 This page intentionally left blank U.S. Department of Energy DVP-June 2013, Shirley Basin South, Wyoming September 2013 RIN 13065426 Page i Contents Sampling Event Summary ...............................................................................................................1 Shirley Basin South, Wyoming, Disposal Site Sample Location Map ............................................3 Data Assessment Summary ..............................................................................................................5 Water Sampling Field Activities Verification Checklist .............................................................7

90

Star forming galaxies in the Hercules cluster: Halpha imaging of A2151  

E-Print Network (OSTI)

This paper presents the first results of an Halpha imaging survey of galaxies in the central regions of the A2151 cluster. A total of 50 sources were detected in Halpha. The morphologies of the 43 H$\\alpha$ selected galaxies range from grand design spirals and interacting galaxies to blue compacts and tidal dwarfs or isolated extragalactic HII regions, spanning a range of magnitudes of -21 <= MB <= -12.5 mag. A comparison with the clusters Coma and A1367 and a sample of field galaxies has shown the presence of cluster galaxies with L(Halpha) lower than expected for their MB, a consecuence of the cluster environment. This fact results in differences in the L(Halpha) vs. EW(Halpha) and L(H\\alpha) distributions of the clusters with respect to the field, and in cluster to cluster variations of these quantities, which we propose are driven by a global cluster property as the total mass. Overall, we conclude that both, the global cluster environment as well as the cluster merging history play a non negligible...

Cedres, B; Vílchez, J M; Reverte, D; Petropolou, V; Hernandez-Fernandez, J

2009-01-01T23:59:59.000Z

91

Chemistry of Tantalum Clusters in Solution And on SiO(2) Supports: Analogies And Contrasts  

Science Conference Proceedings (OSTI)

Tantalum clusters have been synthesized from Ta(CH{sub 2}Ph){sub 5} on the surface of porous fumed SiO{sub 2}. When these clusters are small, incorporating, on average, several Ta atoms, their chemistry is similar to that of molecular tantalum clusters (and other early transition-metal) clusters. For example, The Ta-Ta bonds in these small supported clusters have been characterized by extended X-ray absorption fine structure (EXAFS), IR, and UV-vis spectroscopy, being similar to those in molecular analogues. The redox reactions of the supported clusters, characterized by X-ray absorption near-edge structure, are analogous to those of early transition-metal clusters in solution. In contrast to the largest of these clusters in solution and in the solid state, those supported on SiO{sub 2} are raftlike, facilitating the substantial metal-support-oxygen bonding that is evident in the EXAFS spectra. Samples consisting of tantalum clusters on SiO{sub 2} catalyze alkane disproportionation and the conversion of methane with n-butane to give other alkanes, but catalytic properties of analogous clusters in solution have barely been explored.

Nemana, S.; Okamoto, N.L.; Browning, N.D.; Gates, B.C.

2009-06-03T23:59:59.000Z

92

Clusters and the Cosmic Web  

E-Print Network (OSTI)

We discuss the intimate relationship between the filamentary features and the rare dense compact cluster nodes in this network, via the large scale tidal field going along with them, following the cosmic web theory developed Bond et al. The Megaparsec scale tidal shear pattern is responsible for the contraction of matter into filaments, and its link with the cluster locations can be understood through the implied quadrupolar mass distribution in which the clusters are to be found at the sites of the overdense patches. We present a new technique for tracing the cosmic web, identifying planar walls, elongated filaments and cluster nodes in the galaxy distribution. This will allow the practical exploitation of the concept of the cosmic web towards identifying and tracing the locations of the gaseous WHIM. These methods, the Delaunay Tessellation Field Estimator (DTFE) and the Morphology Multiscale Filter (MMF) find their basis in computational geometry and visualization.

Rien van de Weygaert

2006-07-24T23:59:59.000Z

93

Properties of the Intracluster Medium in an Ensemble of Nearby Galaxy Clusters  

E-Print Network (OSTI)

We present a systematic analysis of the intracluster medium (ICM) in an X-ray flux limited sample of 45 galaxy clusters. Using archival ROSAT PSPC data and published ICM temperatures, we present best fit double and single beta model profiles and extract ICM central densities and radial distributions. We use numerical cluster simulations to estimate uncertainties for all measurements. We examine the ICM properties within the context of models of structure formation and galaxy feedback. We present best fit ICM mass-temperature MICM-TX relations for MICM calculated within R500 and 1Mpc. These relations exhibit small scatter (17%), providing evidence of regularity in large, X-ray flux limited cluster ensembles. The slope of the MICM-TX relation (at limiting radius R500) is steeper than the self-similar expectation by 4.3sigma. There is a mild dependence of ICM mass fraction fICM on TX; the clusters with ICM temperatures below 5keV have a lower mass fraction =0.160\\pm0.008 than hotter clusters =0.212\\pm0.006 (H0=50; 90% conf intervals). Our large, X-ray flux limited cluster sample provides no evidence for a more extended radial ICM distribution in low TX clusters down to the sample limit of 2.4keV. We find that density variations in simulated clusters cause MICM to be overestimated by 12%. We also use simulations to estimate an fICM depletion factor at R500. We use the bias corrected mean fICM within the hotter cluster subsample as a lower limit on the cluster baryon fraction. In combination with nucleosynthesis constraints this measure provides a firm upper limit on the density parameter for clustered matter Omega_M<0.36\\pm0.01 (H0=50).

Joe Mohr; Ben Mathiesen; Gus Evrard

1999-01-20T23:59:59.000Z

94

Completion Report for Well Cluster ER-6-1  

SciTech Connect

Well Cluster ER-6-1 was constructed for the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office in support of the Nevada Environmental Restoration Division at the Nevada Test Site, Nye County, Nevada. This work was initiated as part of the Groundwater Characterization Project, now known as the Underground Test Area Project. The well cluster is located in southeastern Yucca Flat. Detailed lithologic descriptions with stratigraphic assignments for Well Cluster ER-6-1 are included in this report. These are based on composite drill cuttings collected every 3 meters and conventional core samples taken below 639 meters, supplemented by geophysical log data. Detailed petrographic, chemical, and mineralogical studies of rock samples were conducted on 11 samples to resolve complex interrelationships between several of the Tertiary tuff units. Additionally, paleontological analyses by the U.S. Geological Survey confirmed the stratigraphic assignments below 539 meters within the Paleozoic sedimentary section. All three wells in the Well ER-6-1 cluster were drilled within the Quaternary and Tertiary alluvium section, the Tertiary volcanic section, and into the Paleozoic sedimentary section.

Bechtel Nevada

2004-10-01T23:59:59.000Z

95

Rain sampling device  

DOE Patents (OSTI)

The present invention constitutes a rain sampling device adapted for independent operation at locations remote from the user which allows rainfall to be sampled in accordance with any schedule desired by the user. The rain sampling device includes a mechanism for directing wet precipitation into a chamber, a chamber for temporarily holding the precipitation during the process of collection, a valve mechanism for controllably releasing samples of the precipitation from the chamber, a means for distributing the samples released from the holding chamber into vessels adapted for permanently retaining these samples, and an electrical mechanism for regulating the operation of the device. 11 figures.

Nelson, D.A.; Tomich, S.D.; Glover, D.W.; Allen, E.V.; Hales, J.M.; Dana, M.T.

1991-05-14T23:59:59.000Z

96

Automatic decentralized clustering for wireless sensor networks  

Science Conference Proceedings (OSTI)

We propose a decentralized algorithm for organizing an ad hoc sensor network into clusters. Each sensor uses a random waiting timer and local criteria to determine whether to form a new cluster or to join a current cluster. The algorithm operates without ... Keywords: clustering algorithm, random waiting timer, wireless sensor networks

Chih-Yu Wen; William A. Sethares

2005-10-01T23:59:59.000Z

97

Navigating massive data sets via local clustering  

Science Conference Proceedings (OSTI)

This paper introduces a scalable method for feature extraction and navigation of large data sets by means of local clustering, where clusters are modeled as overlapping neighborhoods. Under the model, intra-cluster association and external differentiation ... Keywords: association, confidence, nearest neighbor, soft clustering

Michael E. Houle

2003-08-01T23:59:59.000Z

98

Quality Reference Samples  

Science Conference Proceedings (OSTI)

Peer-reviewed fats and oils related performance-based control samples for lab quality assurance and quality control. Quality Reference Samples Certified Reference Materials (CRM) aocs certified Certified Reference Materials chemists CRM fat fats lab labo

99

September 2004 Water Sampling  

Office of Legacy Management (LM)

information documented on the field data sheets? Yes 18. Was the presence or absence of ice in the cooler documented at every sample location? NA Sample chilling was not required....

100

Sampling for information and structure preservation when mining large data bases  

Science Conference Proceedings (OSTI)

The unsupervised learning process of identifying data clusters on large databases, in common use nowadays, requires an extremely costly computational effort. The analysis of a large volume of data makes it impossible to handle it in the computer's main ... Keywords: clustering, data mining, large databases, preprocessing, sampling

Angel Kuri-Morales; Alexis Lozano

2010-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

September 2004 Water Sampling  

Office of Legacy Management (LM)

3 3 Groundwater and Surface Water Sampling at the Slick Rock East and West, Colorado, Processing Sites November 2013 LMS/SRE/SRW/S0913 This page intentionally left blank U.S. Department of Energy DVP-September 2013, Slick Rock, Colorado November 2013 RIN 13095593 Page i Contents Sampling Event Summary ...............................................................................................................1 Slick Rock East and West, Colorado, Processing Sites, Sample Location Map .............................5 Data Assessment Summary ..............................................................................................................7 Water Sampling Field Activities Verification Checklist .............................................................9

102

September 2004 Water Sampling  

Office of Legacy Management (LM)

Old and New Rifle, Old and New Rifle, Colorado, Processing Sites August 2013 LMS/RFN/RFO/S00613 This page intentionally left blank U.S. Department of Energy DVP-June 2013, Rifle, Colorado August 2013 RIN 13065380 Page i Contents Sampling Event Summary ...............................................................................................................1 Sample Location Map, New Rifle, Colorado, Processing Site ........................................................5 Sample Location Map, Old Rifle, Colorado, Processing Site ..........................................................6 Data Assessment Summary ..............................................................................................................7 Water Sampling Field Activities Verification Checklist .............................................................9

103

September 2004 Water Sampling  

NLE Websites -- All DOE Office Websites (Extended Search)

3 3 Groundwater and Surface Water Sampling at the Tuba City, Arizona, Disposal Site November 2013 LMS/TUB/S00813 This page intentionally left blank U.S. Department of Energy DVP-August 2013, Tuba City, Arizona November 2013 RIN 13085553 Page i Contents Sampling Event Summary ...............................................................................................................1 Tuba City, Arizona, Disposal Site, Sample Location Map ..............................................................7 Data Assessment Summary ..............................................................................................................9 Water Sampling Field Activities Verification Checklist ...........................................................11

104

September 2004 Water Sampling  

NLE Websites -- All DOE Office Websites (Extended Search)

and October 2013 and October 2013 Groundwater Sampling at the Bluewater, New Mexico, Disposal Site December 2013 LMS/BLU/S00813 This page intentionally left blank U.S. Department of Energy DVP-August and October 2013, Bluewater, New Mexico December 2013 RIN 13085537 and 13095651 Page i Contents Sampling Event Summary ...............................................................................................................1 Private Wells Sampled August 2013 and October 2013, Bluewater, NM, Disposal Site ................3 Data Assessment Summary ..............................................................................................................5 Water Sampling Field Activities Verification Checklist .............................................................7

105

September 2004 Water Sampling  

Office of Legacy Management (LM)

Riverton, Wyoming, Riverton, Wyoming, Processing Site September 2013 LMS/RVT/S00613 This page intentionally left blank U.S. Department of Energy DVP-June 2013, Riverton, Wyoming September 2013 RIN 13065379 Page i Contents Sampling Event Summary ...............................................................................................................1 Riverton, Wyoming, Processing Site, Sample Location Map .........................................................5 Data Assessment Summary ..............................................................................................................7 Water Sampling Field Activities Verification Checklist .............................................................9 Laboratory Performance Assessment ........................................................................................11

106

GAMMA RAYS FROM STAR FORMATION IN CLUSTERS OF GALAXIES  

SciTech Connect

Star formation in galaxies is observed to be associated with gamma-ray emission, presumably from non-thermal processes connected to the acceleration of cosmic-ray nuclei and electrons. The detection of gamma rays from starburst galaxies by the Fermi Large Area Telescope (LAT) has allowed the determination of a functional relationship between star formation rate and gamma-ray luminosity. Since star formation is known to scale with total infrared (8-1000 {mu}m) and radio (1.4 GHz) luminosity, the observed infrared and radio emission from a star-forming galaxy can be used to quantitatively infer the galaxy's gamma-ray luminosity. Similarly, star-forming galaxies within galaxy clusters allow us to derive lower limits on the gamma-ray emission from clusters, which have not yet been conclusively detected in gamma rays. In this study, we apply the functional relationships between gamma-ray luminosity and radio and IR luminosities of galaxies derived by the Fermi Collaboration to a sample of the best candidate galaxy clusters for detection in gamma rays in order to place lower limits on the gamma-ray emission associated with star formation in galaxy clusters. We find that several clusters have predicted gamma-ray emission from star formation that are within an order of magnitude of the upper limits derived in Ackermann et al. based on non-detection by Fermi-LAT. Given the current gamma-ray limits, star formation likely plays a significant role in the gamma-ray emission in some clusters, especially those with cool cores. We predict that both Fermi-LAT over the course of its lifetime and the future Cerenkov Telescope Array will be able to detect gamma-ray emission from star-forming galaxies in clusters.

Storm, Emma M.; Jeltema, Tesla E.; Profumo, Stefano [Department of Physics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)

2012-08-20T23:59:59.000Z

107

Galaxy Formation at z~3: Constraints from Spatial Clustering  

E-Print Network (OSTI)

We use N-body simulations combined with semi-analytic models to compute the clustering properties of modeled galaxies at z~3, and confront these predictions with the clustering properties of the observed population of Lyman-break galaxies (LBGs). Several scenarios for the nature of LBGs are explored, which may be broadly categorized into models in which high-redshift star formation is driven by collisional starbursts and those in which quiescent star formation dominates. For each model, we make predictions for the LBG overdensity distribution, the variance of counts-in-cells, the correlation length, and close pair statistics. Models which assume a one-to-one relationship between massive dark-matter halos and galaxies are disfavored by close pair statistics, as are models in which colliding halos are associated with galaxies in a simplified way. However, when modeling of gas consumption and star formation is included using a semi-analytic treatment, the quiescent and collisional starburst models predict similar clustering properties and none of these models can be ruled out based on the available clustering data. None of the ``realistic'' models predict a strong dependence of clustering amplitude on the luminosity threshold of the sample, in apparent conflict with some observational results.

Risa H. Wechsler; Rachel S. Somerville; James S. Bullock; Tsafrir S. Kolatt; Joel R. Primack; George R. Blumenthal; Avishai Dekel

2000-11-14T23:59:59.000Z

108

Consensus clustering in complex networks  

E-Print Network (OSTI)

The community structure of complex networks reveals both their organization and hidden relationships among their constituents. Most community detection methods currently available are not deterministic, and their results typically depend on the specific random seeds, initial conditions and tie-break rules adopted for their execution. Consensus clustering is used in data analysis to generate stable results out of a set of partitions delivered by stochastic methods. Here we show that consensus clustering can be combined with any existing method in a self-consistent way, enhancing considerably both the stability and the accuracy of the resulting partitions. This framework is also particularly suitable to monitor the evolution of community structure in temporal networks. An application of consensus clustering to a large citation network of physics papers demonstrates its capability to keep track of the birth, death and diversification of topics.

Lancichinetti, Andrea; 10.1038/srep00336

2012-01-01T23:59:59.000Z

109

AGE AND MASS FOR 920 LARGE MAGELLANIC CLOUD CLUSTERS DERIVED FROM 100 MILLION MONTE CARLO SIMULATIONS  

SciTech Connect

We present new age and mass estimates for 920 stellar clusters in the Large Magellanic Cloud (LMC) based on previously published broadband photometry and the stellar cluster analysis package, MASSCLEANage. Expressed in the generic fitting formula, d{sup 2} N/dMdt{proportional_to}M{sup {alpha}} t{sup {beta}}, the distribution of observed clusters is described by {alpha} = -1.5 to -1.6 and {beta} = -2.1 to -2.2. For 288 of these clusters, ages have recently been determined based on stellar photometric color-magnitude diagrams, allowing us to gauge the confidence of our ages. The results look very promising, opening up the possibility that this sample of 920 clusters, with reliable and consistent age, mass, and photometric measures, might be used to constrain important characteristics about the stellar cluster population in the LMC. We also investigate a traditional age determination method that uses a {chi}{sup 2} minimization routine to fit observed cluster colors to standard infinite-mass limit simple stellar population models. This reveals serious defects in the derived cluster age distribution using this method. The traditional {chi}{sup 2} minimization method, due to the variation of U, B, V, R colors, will always produce an overdensity of younger and older clusters, with an underdensity of clusters in the log (age/yr) = [7.0, 7.5] range. Finally, we present a unique simulation aimed at illustrating and constraining the fading limit in observed cluster distributions that includes the complex effects of stochastic variations in the observed properties of stellar clusters.

Popescu, Bogdan; Hanson, M. M. [Department of Physics, University of Cincinnati, P.O. Box 210011, Cincinnati, OH 45221-0011 (United States); Elmegreen, Bruce G., E-mail: popescb@mail.uc.edu, E-mail: margaret.hanson@uc.edu, E-mail: bge@us.ibm.com [IBM Research Division, T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598 (United States)

2012-06-01T23:59:59.000Z

110

Massively parallel Wang Landau sampling on multiple GPUs  

Science Conference Proceedings (OSTI)

Wang Landau sampling is implemented on the Graphics Processing Unit (GPU) with the Compute Unified Device Architecture (CUDA). Performances on three different GPU cards, including the new generation Fermi architecture card, are compared with that on a Central Processing Unit (CPU). The parameters for massively parallel Wang Landau sampling are tuned in order to achieve fast convergence. For simulations of the water cluster systems, we obtain an average of over 50 times speedup for a given workload.

Yin, Junqi [ORNL; Landau, D. P. [UGA

2012-01-01T23:59:59.000Z

111

September 2004 Water Sampling  

Office of Legacy Management (LM)

Green River, Utah, Disposal Site Green River, Utah, Disposal Site August 2013 LMS/GRN/S00613 This page intentionally left blank U.S. Department of Energy DVP-June 2013, Green River, Utah August 2013 RIN 13065402 Page i Contents Sampling Event Summary ...............................................................................................................1 Data Assessment Summary ..............................................................................................................7 Water Sampling Field Activities Verification Checklist .............................................................9 Laboratory Performance Assessment ........................................................................................11 Sampling Quality Control Assessment ......................................................................................18

112

Beacon Project - Unpredictable Sampling  

Science Conference Proceedings (OSTI)

... or undetected tampering), with the random number generator used for sampling can lead to erroneous estimates of the percentage of faulty parts. ...

2013-07-25T23:59:59.000Z

113

FANS - Sample Change  

Science Conference Proceedings (OSTI)

... result of neutrons with incident energies higher than ... between the sample position and the detector bank. ... 60 to 300 seconds per energy point and ...

114

September 2004 Water Sampling  

Office of Legacy Management (LM)

field procedures? Yes List any Program Directives or other documents, SOPs, instructions. Work Order Letter dated May 1, 2013. Program Directive SHL 2013 01. 2. Were the sampling...

115

FANS - Sample Change  

Science Conference Proceedings (OSTI)

... This is achieved by placing a cadmium shield between the sample position and the detector bank. In order to place the ...

116

Rotation invarient simultaneous clustering and dictionary learning  

E-Print Network (OSTI)

In this paper, we present an approach that simultaneously clusters database members and learns dictionaries from the clusters. The method learns dictionaries in the Radon transform domain, while clustering in the image domain. The main feature of the proposed approach is that it provides rotation invariant clustering which is useful in Content Based Image Retrieval (CBIR). We demonstrate through experimental results that the proposed rotation invariant clustering provides better retrieval performance than the standard Gabor-based method that has similar objectives. Index Terms — Radon transform, rotation invariance, clustering, dictionary learning, CBIR.

Yi-chen Chen; Challa S. Sastry; Vishal M. Patel; P. Jonathon Phillips

2012-01-01T23:59:59.000Z

117

Interpreting the Clustering of Distant Red Galaxies  

SciTech Connect

We analyze the angular clustering of z {approx} 2.3 distant red galaxies (DRGs) measured by Quadri et al. (2008). We find that, with robust estimates of the measurement errors and realistic halo occupation distribution modeling, the measured clustering can be well fit within standard halo occupation models, in contrast to previous results. However, in order to fit the strong break in w({theta}) at {theta} = 10{double_prime}, nearly all satellite galaxies in the DRG luminosity range are required to be DRGs. Within this luminosity-threshold sample, the fraction of galaxies that are DRGs is {approx} 44%, implying that the formation of DRGs is more efficient for satellite galaxies than for central galaxies. Despite the evolved stellar populations contained within DRGs at z = 2.3, 90% of satellite galaxies in the DRG luminosity range have been accreted within 500 Myr. Thus, satellite DRGs must have known they would become satellites well before the time of their accretion. This implies that the formation of DRGs correlates with large-scale environment at fixed halo mass, although the large-scale bias of DRGs can be well fit without such assumptions. Further data are required to resolve this issue. Using the observational estimate that {approx} 30% of DRGs have no ongoing star formation, we infer a timescale for star formation quenching for satellite galaxies of 450 Myr, although the uncertainty on this number is large. However, unless all non-star forming satellite DRGs were quenched before accretion, the quenching timescale is significantly shorter than z {approx} 0 estimates. Down to the completeness limit of the Quadri et al sample, we find that the halo masses of central DRGs are {approx} 50% higher than non-DRGs in the same luminosity range, but at the highest halo masses the central galaxies are DRGs only {approx} 2/3 of the time.

Tinker, Jeremy L.; /BCCP, Berkeley; Wechsler, Risa H.; /KIPAC, Menlo Park /SLAC; Zheng, Zheng; /Princeton, Inst. Advanced Study

2009-08-03T23:59:59.000Z

118

Evolution of Substructure in Galaxy Clusters as Observed in X-Rays  

E-Print Network (OSTI)

Clusters of galaxies are the largest gravitationally-bound objects in the Universe, having diameters on order of Mpc. Our work asked whether their shapes (morphologies) change over time as the Universe ages. We observed a sample of 165 galaxy clusters, at 0.1 < z < 1.3. A variety of measures were used to quantify the shapes of galaxy clusters. Archive observations from the Chandra X-Ray Observatory were used. Morphology evolution was probed at two different distances from clusters' centers -- 300 kpc and 500 kpc -- for comparison. In almost all cases, we were able to rule out that clusters retain their morphology over the history of the Universe, which is in agreement with our current picture of large-scale structure formation. In addition, we found that ellipticities, as a means of quantifying morphologies, are of limited use in studies such as this work.

Brian C. Hart

2008-01-28T23:59:59.000Z

119

Evolution of the X-ray Properties of Clusters of Galaxies  

E-Print Network (OSTI)

The amount and nature of the evolution of the X-ray properties of clusters of galaxies provides information on the formation of structure in the universe and on the properties of the universe itself. The cluster luminosity - temperature relation does not evolve strongly, suggesting that the hot X-ray gas had a more complicated thermodynamic history than simply collapsing into the cluster potential well. Cluster X-ray luminosities do evolve. The dependence of this evolution on redshift and luminosity is characterized using two large high redshift samples. Cluster X-ray temperatures also evolve. This evolution constrains the dark matter and dark energy content of the universe as well as other parameters of cosmological interest.

J. Patrick Henry

2002-07-06T23:59:59.000Z

120

Research on Fault Diagnosis of Marine Diesel Engine Based on Grey Relational Analysis and Kernel Fuzzy C-means Clustering  

Science Conference Proceedings (OSTI)

According to the problem of small samples and nonlinear feature in fault diagnosis of marine diesel engine, comprehensively using the methods of grey relational analysis and kernel fuzzy c-means clustering, a method solving fault diagnosis of marine ... Keywords: marine diesel engine, fault diagnosis, grey relational analysis, kernel fuzzy c-means clustering

Xiuyan Peng; Yanyou Chai; Yanyou Chai; Liufeng Xu; Xinjiang Man

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Fast Identification of Gene Clusters in Prokaryotic Genomes ... - CECM  

E-Print Network (OSTI)

linear space practical complexity. The number of clusters for the data set of 12 genomes goes from 199 clusters (? = 3, ? = 2. and ? = 100) to 930 clusters (? = 2,  ...

122

Sampling system and method  

DOE Patents (OSTI)

The present disclosure provides an apparatus and method for coupling conduit segments together. A first pump obtains a sample and transmits it through a first conduit to a reservoir accessible by a second pump. The second pump further conducts the sample from the reservoir through a second conduit.

Decker, David L.; Lyles, Brad F.; Purcell, Richard G.; Hershey, Ronald Lee

2013-04-16T23:59:59.000Z

123

Cold Fronts in CDM clusters  

E-Print Network (OSTI)

Recently, high-resolution Chandra observations revealed the existence of very sharp features in the X-ray surface brightness and temperature maps of several clusters (Vikhlinin et. al., 2001). These features, called ``cold fronts'', are characterized by an increase in surface brightness by a factor >2 over 10-50 kpc, accompanied by a drop in temperature of a similar magnitude. The existence of such sharp gradients can be used to put interesting constraints on the physics of the intracluster medium (ICM), if their mechanism and longevity are well understood. Here, we present results of a search for cold fronts in high-resolution simulations of galaxy clusters in cold dark matter (CDM) models. We show that sharp gradients with properties similar to those of observed cold fronts naturally arise in cluster mergers when the shocks heat gas surrounding the merging sub-cluster, while its dense core remains relatively cold. The compression induced by supersonic motions and shock heating during the merger enhance the amplitude of gas density and temperature gradients across the front. Our results indicate that cold fronts are non-equilibrium transient phenomena and can be observed for a period of less than a billion years. We show that the velocity and density fields of gas surrounding the cold front can be very irregular which would complicate analyses aiming to put constraints on the physical conditions of the intracluster medium in the vicinity of the front.

Daisuke Nagai; Andrey V. Kravtsov

2002-06-26T23:59:59.000Z

124

An Improved Cluster Richness Estimator  

Science Conference Proceedings (OSTI)

Minimizing the scatter between cluster mass and accessible observables is an important goal for cluster cosmology. In this work, we introduce a new matched filter richness estimator, and test its performance using the maxBCG cluster catalog. Our new estimator significantly reduces the variance in the L{sub X}-richness relation, from {sigma}{sub lnL{sub X}}{sup 2} = (0.86 {+-} 0.02){sup 2} to {sigma}{sub lnL{sub X}}{sup 2} = (0.69 {+-} 0.02){sup 2}. Relative to the maxBCG richness estimate, it also removes the strong redshift dependence of the richness scaling relations, and is significantly more robust to photometric and redshift errors. These improvements are largely due to our more sophisticated treatment of galaxy color data. We also demonstrate the scatter in the L{sub X}-richness relation depends on the aperture used to estimate cluster richness, and introduce a novel approach for optimizing said aperture which can be easily generalized to other mass tracers.

Rozo, Eduardo; /Ohio State U.; Rykoff, Eli S.; /UC, Santa Barbara; Koester, Benjamin P.; /Chicago U. /KICP, Chicago; McKay, Timothy; /Michigan U.; Hao, Jiangang; /Michigan U.; Evrard, August; /Michigan U.; Wechsler, Risa H.; /SLAC; Hansen, Sarah; /Chicago U. /KICP, Chicago; Sheldon, Erin; /New York U.; Johnston, David; /Houston U.; Becker, Matthew R.; /Chicago U. /KICP, Chicago; Annis, James T.; /Fermilab; Bleem, Lindsey; /Chicago U.; Scranton, Ryan; /Pittsburgh U.

2009-08-03T23:59:59.000Z

125

2003 CBECS Sample Design  

U.S. Energy Information Administration (EIA) Indexed Site

Technical Information > Sample Design Technical Information > Sample Design How the Survey Was Conducted 2003 Commercial Buildings Energy Consumption Survey: Sample Design Introduction The Commercial Buildings Energy Consumption Survey (CBECS) is conducted quadrennially by the Energy Information Administration (EIA) to provide basic statistical information about energy consumption and expenditures in U.S. commercial buildings and information about energy-related characteristics of these buildings. The survey is based upon a sample of commercial buildings selected according to the sample design requirements described below. A “building,” as opposed to an “establishment,” is the basic unit of analysis for the CBECS because the building is the energy-consuming unit. The 2003 CBECS was the eighth survey conducted since 1979

126

Biological sample collector  

DOE Patents (OSTI)

A biological sample collector is adapted to a collect several biological samples in a plurality of filter wells. A biological sample collector may comprise a manifold plate for mounting a filter plate thereon, the filter plate having a plurality of filter wells therein; a hollow slider for engaging and positioning a tube that slides therethrough; and a slide case within which the hollow slider travels to allow the tube to be aligned with a selected filter well of the plurality of filter wells, wherein when the tube is aligned with the selected filter well, the tube is pushed through the hollow slider and into the selected filter well to sealingly engage the selected filter well and to allow the tube to deposit a biological sample onto a filter in the bottom of the selected filter well. The biological sample collector may be portable.

Murphy, Gloria A. (French Camp, CA)

2010-09-07T23:59:59.000Z

127

Sample push out fixture  

DOE Patents (OSTI)

This invention generally relates to the remote removal of pelletized samples from cylindrical containment capsules. V-blocks are used to receive the samples and provide guidance to push out rods. Stainless steel liners fit into the v-channels on the v-blocks which permits them to be remotely removed and replaced or cleaned to prevent cross contamination between capsules and samples. A capsule holder securely holds the capsule while allowing manual up/down and in/out movement to align each sample hole with the v-blocks. Both end sections contain identical v-blocks; one that guides the drive out screw and rods or manual push out rods and the other to receive the samples as they are driven out of the capsule.

Biernat, John L.

2000-02-22T23:59:59.000Z

128

Sample Changes and Issues  

U.S. Energy Information Administration (EIA) Indexed Site

Sample and Model Issues Sample and Model Issues Summary Our comprehensive review of the EIA 914 has confirmed that discrepancies can arise between estimates for December of one year and January of the next. These are most evident for Texas estimates between December 2008 and January 2009. Reports now available from HPDI show that production for all the companies we sampled in both 2008 and 2009 rose by about 60 million cubic feet per day (MMcf/d) in January and that total production in Texas rose by a similar amount. Our estimate was a decrease of 360 MMcf/d. Why the difference? Computationally, EIA-914 estimates depend on two factors: * Reports from the companies in the survey sample * An expansion factor to estimate total production from the sample's reported

129

Completion Report for Well Cluster ER-5-4  

Science Conference Proceedings (OSTI)

Well Cluster ER-5-4 was drilled for the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, in support of the Nevada Environmental Restoration Project at the Nevada Test Site, Nye County, Nevada. The cluster consists of two wells, positioned about 30 meters apart on the same drill pad, constructed as part of a hydrogeologic investigation program for Frenchman Flat at the Nevada Test Site. Detailed lithologic descriptions with preliminary stratigraphic assignments for the well cluster are included in this report. These are based on composite drill cuttings collected every 3 meters, and 156 sidewall samples taken at various depths below 192 meters in both boreholes, supplemented by geophysical log data. Detailed petrographic, chemical, and mineralogical studies of rock samples were conducted on 122 samples. Well ER-5-4 penetrated approximately 1,120 meters of Quaternary and Tertiary alluvium before reaching total depth in Tertiary volcanic rocks at 1,137.5 meters. The deeper Well ER-5-4 No.2 penetrated 1,120.4 meters of alluvial sediments, and was terminated within Tertiary volcanic rocks at a depth of 2,133.6 meters, indicating that Paleozoic rocks are deeper than expected at this site.

U.S. Department of Energy, National Nuclear Security Administration, Nevada Site Office; Bechtel Nevada

2005-02-01T23:59:59.000Z

130

Environmental Business Cluster EBC | Open Energy Information  

Open Energy Info (EERE)

Cluster EBC Cluster EBC Jump to: navigation, search Name Environmental Business Cluster (EBC) Place San Jose, California Zip CA 95113 Product The Environmental Business Cluster is a not-for-profit incubator sponsored by major financial groups such as Citibank, and San Jose University. It has facilitated funding for 50 eco-related start-up businesses. References Environmental Business Cluster (EBC)[1] LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! This article is a stub. You can help OpenEI by expanding it. Environmental Business Cluster (EBC) is a company located in San Jose, California . References ↑ "Environmental Business Cluster (EBC)" Retrieved from "http://en.openei.org/w/index.php?title=Environmental_Business_Cluster_EBC&oldid=345024

131

Carbon Fiber Cluster Strategy | ornl.gov  

NLE Websites -- All DOE Office Websites (Extended Search)

Carbon Fiber Cluster Strategy SHARE Carbon Fiber Cluster Strategy ORNL has a 40-year history in R&D on fiber-reinforced composite materials, and has been leading DOE's low-cost...

132

Cluster Software Tools: Beauty is in Simplicity  

Science Conference Proceedings (OSTI)

Beowulf cluster has created a lot of impact by delivering an excellent prize/performance and scalable computing systems to high performance computing community. Nevertheless, the widespread use of beowulf clusters has not happened as fast as it should ...

Putchong Uthayopas

2001-10-01T23:59:59.000Z

133

Perspectives for logistics clusters development in Russia  

E-Print Network (OSTI)

This thesis is a normative work aimed at identifying locations in Russia with high, medium and unclear potentials for logistics cluster development. As a framework this work uses four different models of logistics clusters: ...

Tantsuyev, Andriy

2012-01-01T23:59:59.000Z

134

Revisiting Climate Region Definitions via Clustering  

Science Conference Proceedings (OSTI)

This paper introduces a new distance metric that enables the clustering of general climatic time series. Clustering methods have been frequently used to partition a domain of interest into distinct climatic zones. However, previous techniques ...

Robert Lund; Bo Li

2009-04-01T23:59:59.000Z

135

Improvements to the quantum evolutionary clustering  

Science Conference Proceedings (OSTI)

In previous work, a novel approach to data clustering based on quantum evolutionary algorithm has been proposed. In a comparison to other evolutionary clustering algorithms, the approach showed a high performance in terms of effectiveness and quality ...

Chafika Ramdane, Mohamed-Khireddine Kholladi

2013-05-01T23:59:59.000Z

136

Cluster Dynamics in a Circulating Fluidized Bed  

Science Conference Proceedings (OSTI)

A common hydrodynamic feature in industrial scale circulating fluidized beds is the presence of clusters. The continuous formation and destruction of clusters strongly influences particle hold-up, pressure drop, heat transfer at the wall, and mixing. In this paper fiber optic data is analyzed using discrete wavelet analysis to characterize the dynamic behavior of clusters. Five radial positions at three different axial locations under five different operating were analyzed using discrete wavelets. Results are summarized with respect to cluster size and frequency.

Guenther, C.P.; Breault, R.W.

2006-11-01T23:59:59.000Z

137

Galaxy Orientations in the Coma Cluster  

E-Print Network (OSTI)

We have examined the orientations of early-type galaxies in the Coma cluster to see whether the well-established tendency for brightest cluster galaxies to share the same major axis orientation as their host cluster also extends to the rest of the galaxy population. We find no evidence of any preferential orientations of galaxies within Coma or its surroundings. The implications of this result for theories of the formation of clusters and galaxies (particularly the first-ranked members) are discussed.

Lisa Torlina; Roberto De Propris; Michael J. West

2007-03-16T23:59:59.000Z

138

Cluster Expansion Methods - Progress and Outlook  

Science Conference Proceedings (OSTI)

Symposium, Computational Thermodynamics and Kinetics. Presentation Title, Cluster Expansion Methods - Progress and Outlook. Author(s), Axel van de Walle .

139

Clustering hypertext with applications to web searching  

Science Conference Proceedings (OSTI)

Keywords: cluster annotation, feature combination, high-dimensional data, hyperlinks, sparse data, toric k-means algorithm, vector space model

Dharmendra S. Modha; W. Scott Spangler

2000-05-01T23:59:59.000Z

140

Letter to the Editor Explaining the mass-to-light ratios of globular clusters  

E-Print Network (OSTI)

Context. The majority of observed mass-to-light ratios of globular clusters are too low to be explained by ‘canonical’ cluster models, in which dynamical effects are not accounted for. Moreover, these models do not reproduce a recently reported trend of increasing M/L with cluster mass, but instead predict mass-to-light ratios that are independent of cluster mass for a fixed age and metallicity. Aims. This study aims to explain the M/L of globular clusters in four galaxies by including stellar evolution, stellar remnants, and the preferential loss of low-mass stars due to energy equipartition. Methods. Analytical cluster models are applied that account for stellar evolution and dynamical cluster dissolution to samples of globular clusters in Cen A, the Milky Way, M31 and the LMC. The models include stellar remnants and cover metallicities in the range Z = 0.0004—0.05. Results. Both the low observed mass-to-light ratios and the trend of increasing M/L with cluster mass can be reproduced by including the preferential loss of low-mass stars, assuming reasonable values for the dissolution timescale. This leads to a mass-dependent M/L evolution and increases the explained percentage of the observations from 39 % to 92%. Conclusions. This study shows that the hitherto unexplained discrepancy between observations and models of the massto-light ratios of globular clusters can be explained by dynamical effects, provided that the globular clusters exhibiting low M/L have dissolution timescales within the ranges assumed in this Letter. Furthermore, it substantiates that M/L cannot be assumed to be constant with mass at fixed age and metallicity.

J. M. Diederik Kruijssen

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Thermal Modeling of Hybrid Storage Clusters  

Science Conference Proceedings (OSTI)

There is a lack of thermal models for storage clusters; most existing thermal models do not take into account the utilization of hard drives (HDDs) and solid state disks (SSDs). To address this problem, we build a thermal model for hybrid storage clusters ... Keywords: Cluster, Hybrid, Model, Storage, Thermal

Xunfei Jiang; Maen M. Al Assaf; Ji Zhang; Mohammed I. Alghamdi; Xiaojun Ruan; Tausif Muzaffar; Xiao Qin

2013-09-01T23:59:59.000Z

142

Dynamic clustering using combinatorial particle swarm optimization  

Science Conference Proceedings (OSTI)

Combinatorial Particle Swarm Optimization (CPSO) is a relatively recent technique for solving combinatorial optimization problems. CPSO has been used in different applications, e.g., partitional clustering and project scheduling problems, and it has ... Keywords: Combinatorial optimization problems, Combinatorial particle swarm optimization, Dynamic clustering, Partitional clustering

Hamid Masoud; Saeed Jalili; Seyed Mohammad Hasheminejad

2013-04-01T23:59:59.000Z

143

Architectural support for enhancing security in clusters  

E-Print Network (OSTI)

Cluster computing has emerged as a common approach for providing more comput- ing and data resources in industry as well as in academia. However, since cluster computer developers have paid more attention to performance and cost e±ciency than to security, numerous security loopholes in cluster servers come to the forefront. Clusters usually rely on ¯rewalls for their security, but the ¯rewalls cannot prevent all security attacks; therefore, cluster systems should be designed to be robust to security attacks intrinsically. In this research, we propose architectural supports for enhancing security of clus- ter systems with marginal performance overhead. This research proceeds in a bottom- up fashion starting from enforcing each cluster component's security to building an integrated secure cluster. First, we propose secure cluster interconnects providing con- ¯dentiality, authentication, and availability. Second, a security accelerating network interface card architecture is proposed to enable low performance overhead encryption and authentication. Third, to enhance security in an individual cluster node, we pro- pose a secure design for shared-memory multiprocessors (SMP) architecture, which is deployed in many clusters. The secure SMP architecture will provide con¯dential communication between processors. This will remove the vulnerability of eavesdrop- ping attacks in a cluster node. Finally, to put all proposed schemes together, we propose a security/performance trade-o® model which can precisely predict performance of an integrated secure cluster.

Lee, Man Hee

2008-08-01T23:59:59.000Z

144

Galactic Globular and Open Clusters in the Sloan Digital Sky Survey. I. Crowded Field Photometry and Cluster Fiducial Sequences in ugriz  

E-Print Network (OSTI)

We present photometry for globular and open cluster stars observed with the Sloan Digital Sky Survey (SDSS). In order to exploit over 100 million stellar objects with r < 22.5 mag observed by SDSS, we need to understand the characteristics of stars in the SDSS ugriz filters. While star clusters provide important calibration samples for stellar colors, the regions close to globular clusters, where the fraction of field stars is smallest, are too crowded for the standard SDSS photometric pipeline to process. To complement the SDSS imaging survey, we reduce the SDSS imaging data for crowded cluster fields using the DAOPHOT/ALLFRAME suite of programs and present photometry for 17 globular clusters and 3 open clusters in a SDSS value-added catalog. Our photometry and cluster fiducial sequences are on the native SDSS 2.5-meter ugriz photometric system, and the fiducial sequences can be directly applied to the SDSS photometry without relying upon any transformations. Model photometry for red giant branch and main...

An, Deokkeun; Clem, James L; Yanny, Brian; Rockosi, Constance M; Morrison, Heather L; Harding, Paul; Gunn, James E; Prieto, Carlos Allende; Beers, Timothy C; Cudworth, Kyle M; Ivans, Inese I; Ivezic, Zeljko; Lee, Young Sun; Lupton, Robert H; Bizyaev, Dmitry; Brewington, Howard; Malanushenko, Elena; Malanushenko, Viktor; Oravetz, Dan; Pan, Kaike; Simmons, Audrey; Snedden, Stephanie; Watters, Shannon; York, Donald G

2008-01-01T23:59:59.000Z

145

Galactic Globular and Open Clusters in the Sloan Digital Sky Survey. I. Crowded Field Photometry and Cluster Fiducial Sequences in ugriz  

E-Print Network (OSTI)

We present photometry for globular and open cluster stars observed with the Sloan Digital Sky Survey (SDSS). In order to exploit over 100 million stellar objects with r < 22.5 mag observed by SDSS, we need to understand the characteristics of stars in the SDSS ugriz filters. While star clusters provide important calibration samples for stellar colors, the regions close to globular clusters, where the fraction of field stars is smallest, are too crowded for the standard SDSS photometric pipeline to process. To complement the SDSS imaging survey, we reduce the SDSS imaging data for crowded cluster fields using the DAOPHOT/ALLFRAME suite of programs and present photometry for 17 globular clusters and 3 open clusters in a SDSS value-added catalog. Our photometry and cluster fiducial sequences are on the native SDSS 2.5-meter ugriz photometric system, and the fiducial sequences can be directly applied to the SDSS photometry without relying upon any transformations. Model photometry for red giant branch and main-sequence stars obtained by Girardi et al. cannot be matched simultaneously to fiducial sequences; their colors differ by ~0.02-0.05 mag. Good agreement (< ~0.02 mag in colors) is found with Clem et al. empirical fiducial sequences in u'g'r'i'z' when using the transformation equations in Tucker et al.

Deokkeun An; Jennifer A. Johnson; James L. Clem; Brian Yanny; Constance M. Rockosi; Heather L. Morrison; Paul Harding; James E. Gunn; Carlos Allende Prieto; Timothy C. Beers; Kyle M. Cudworth; Inese I. Ivans; Zeljko Ivezic; Young Sun Lee; Robert H. Lupton; Dmitry Bizyaev; Howard Brewington; Elena Malanushenko; Viktor Malanushenko; Dan Oravetz; Kaike Pan; Audrey Simmons; Stephanie Snedden; Shannon Watters; Donald G. York

2008-07-31T23:59:59.000Z

146

CAeSaR: unified cluster-assignment scheduling and communication reuse for clustered VLIW processors  

Science Conference Proceedings (OSTI)

Clustered architectures have been proposed as a solution to the scalability problem of wide ILP processors. VLIW architectures, being wide-issue by design, benefit significantly from clustering. Such architectures, being both statically scheduled and ... Keywords: cluster assignment, clustered VLIW, instruction scheduling

Vasileios Porpodas; Marcelo Cintra

2013-09-01T23:59:59.000Z

147

September 2004 Water Sampling  

Office of Legacy Management (LM)

was not identified at many groundwater locations. 18. Was the presence or absence of ice in the cooler documented at every sample location? Yes 19. Were water levels measured...

148

Computer Science Sample Occupations  

E-Print Network (OSTI)

Computer Science Sample Occupations COMPUTER OPERATIONS Computer Hardware/ Software Engineer Computer Operator Database Manager/ Administrator Data Entry Operator Operations Manager DESIGN & MANUFACTURING, ENGINEERING Coder CAD Computer Applications Engineers Computer Research Scientist Computer

Ronquist, Fredrik

149

SAMPLING AND ANALYSIS PROTOCOLS  

SciTech Connect

Radiological sampling and analyses are performed to collect data for a variety of specific reasons covering a wide range of projects. These activities include: Effluent monitoring; Environmental surveillance; Emergency response; Routine ambient monitoring; Background assessments; Nuclear license termination; Remediation; Deactivation and decommissioning (D&D); and Waste management. In this chapter, effluent monitoring and environmental surveillance programs at nuclear operating facilities and radiological sampling and analysis plans for remediation and D&D activities will be discussed.

Jannik, T; P Fledderman, P

2007-02-09T23:59:59.000Z

150

Liquid sampling system  

DOE Patents (OSTI)

A conduit extends from a reservoir through a sampling station and back to the reservoir in a closed loop. A jet ejector in the conduit establishes suction for withdrawing liquid from the reservoir. The conduit has a self-healing septum therein upstream of the jet ejector for receiving one end of a double-ended cannula, the other end of which is received in a serum bottle for sample collection. Gas is introduced into the conduit at a gas bleed between the sample collection bottle and the reservoir. The jet ejector evacuates gas from the conduit and the bottle and aspirates a column of liquid from the reservoir at a high rate. When the withdrawn liquid reaches the jet ejector the rate of flow therethrough reduces substantially and the gas bleed increases the pressure in the conduit for driving liquid into the sample bottle, the gas bleed forming a column of gas behind the withdrawn liquid column and interrupting the withdrawal of liquid from the reservoir. In the case of hazardous and toxic liquids, the sample bottle and the jet ejector may be isolated from the reservoir and may be further isolated from a control station containing remote manipulation means for the sample bottle and control valves for the jet ejector and gas bleed.

Larson, Loren L. (Idaho Falls, ID)

1987-01-01T23:59:59.000Z

151

Liquid sampling system  

DOE Patents (OSTI)

A conduit extends from a reservoir through a sampling station and back to the reservoir in a closed loop. A jet ejector in the conduit establishes suction for withdrawing liquid from the reservoir. The conduit has a self-healing septum therein upstream of the jet ejector for receiving one end of a double-ended cannula, the other end of which is received in a serum bottle for sample collection. Gas is introduced into the conduit at a gas bleed between the sample collection bottle and the reservoir. The jet ejector evacuates gas from the conduit and the bottle and aspirates a column of liquid from the reservoir at a high rate. When the withdrawn liquid reaches the jet ejector the rate of flow therethrough reduces substantially and the gas bleed increases the pressure in the conduit for driving liquid into the sample bottle, the gas bleed forming a column of gas behind the withdrawn liquid column and interrupting the withdrawal of liquid from the reservoir. In the case of hazardous and toxic liquids, the sample bottle and the jet ejector may be isolated from the reservoir and may be further isolated from a control station containing remote manipulation means for the sample bottle and control valves for the jet ejector and gas bleed. 5 figs.

Larson, L.L.

1984-09-17T23:59:59.000Z

152

Quantum Computation with Magnetic Clusters  

E-Print Network (OSTI)

We propose a complete, quantitative quantum computing system which satisfies the five DiVincenzo criteria. The model is based on magnetic clusters with uniaxial anisotropy, where standard, two-state qubits are formed utilizing the two lowest-lying states of an anisotropic potential energy. We outline the quantum dynamics required by quantum computing for single qubit structures, and then define a novel measurement scheme in which qubit sates can be measured by sharp changes in current as voltage across the cluster is varied. We then extend the single qubit description to multiple qubit interactions, facilitated specifically by a new entanglement method which propagates the controlled-NOT (C-NOT) quantum gate.

Daniel D. Dorroh; Serkay Olmez; Jian-Ping Wang

2013-05-17T23:59:59.000Z

153

Novel platinum/carbon catalysts with cluster size control for...  

NLE Websites -- All DOE Office Websites (Extended Search)

Project overview - Cluster chemistry - Catalysts and supports * Experimental - Novel catalyst preparation * Results - Metal cluster size - Electrochemical properties * Summary...

154

Tracking Rotational Diffusion of Colloidal Clusters  

E-Print Network (OSTI)

We describe a novel method of tracking the rotational motion of clusters of colloidal particles. Our method utilizes rigid body transfor- mations to determine the rotations of a cluster and extends conventional proven particle tracking techniques in a simple way, thus facilitating the study of rotational dynamics in systems containing or composed of colloidal clusters. We test our method by measuring dynamical properties of simulated Brownian clusters under conditions relevant to microscopy experiments. We then use the technique to track and describe the motions of a real colloidal cluster imaged with confocal microscopy.

Gary L. Hunter; Kazem V. Edmond; Mark T. Elsesser; Eric R. Weeks

2011-07-13T23:59:59.000Z

155

Wafer Replacement Cluster Tool (Presentation);  

DOE Green Energy (OSTI)

This presentation on wafer replacement cluster tool discusses: (1) Platform for advanced R and D toward SAI 2015 cost goal--crystal silicon PV at area costs closer to amorphous Si PV, it's 15% efficiency, inexpensive substrate, and moderate temperature processing (<800 C); (2) Why silicon?--industrial and knowledge base, abundant and environmentally benign, market acceptance, and good efficiency; and (3) Why replace wafers?--expensive, high embedded energy content, and uses 50-100 times more silicon than needed.

Branz, H. M.

2008-04-01T23:59:59.000Z

156

STAR FORMATION IN DENSE CLUSTERS  

SciTech Connect

A model of core-clump accretion with equally likely stopping describes star formation in the dense parts of clusters, where models of isolated collapsing cores may not apply. Each core accretes at a constant rate onto its protostar, while the surrounding clump gas accretes as a power of protostar mass. Short accretion flows resemble Shu accretion and make low-mass stars. Long flows resemble reduced Bondi accretion and make massive stars. Accretion stops due to environmental processes of dynamical ejection, gravitational competition, and gas dispersal by stellar feedback, independent of initial core structure. The model matches the field star initial mass function (IMF) from 0.01 to more than 10 solar masses. The core accretion rate and the mean accretion duration set the peak of the IMF, independent of the local Jeans mass. Massive protostars require the longest accretion durations, up to 0.5 Myr. The maximum protostar luminosity in a cluster indicates the mass and age of its oldest protostar. The distribution of protostar luminosities matches those in active star-forming regions if protostars have a constant birthrate but not if their births are coeval. For constant birthrate, the ratio of young stellar objects to protostars indicates the star-forming age of a cluster, typically {approx}1 Myr. The protostar accretion luminosity is typically less than its steady spherical value by a factor of {approx}2, consistent with models of episodic disk accretion.

Myers, Philip C., E-mail: pmyers@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2011-12-10T23:59:59.000Z

157

Formation of Globular Clusters in Galaxy Mergers  

E-Print Network (OSTI)

We present a high-resolution simulation of globular cluster formation in a galaxy merger. For the first time in such a simulation, individual star clusters are directly identified and followed on their orbits. We quantitatively compare star formation in the merger to that in the unperturbed galaxies. The merging galaxies show a strong starburst, in sharp contrast to their isolated progenitors. Most star clusters form in the tidal tails. With a mass range of $5\\times10^{5}$--$5\\times 10^{6} M_{\\odot}$, they are identified as globular clusters. The merger remnant is an elliptical galaxy. Clusters with different mass or age have different radial distributions in the galaxy. The cluster mass spectrum appears to be roughly log-normal. Our results show that the high specific frequency and bimodal distribution of metallicity observed in elliptical galaxies are natural products of gas-rich mergers, supporting a merger origin for the ellipticals and their globular cluster systems.

Li, Y; Klessen, R S; Li, Yuexing; Low, Mordecai-Mark Mac; Klessen, Ralf S.

2004-01-01T23:59:59.000Z

158

Fluid sampling system  

DOE Patents (OSTI)

An fluid sampling system allows sampling of radioactive liquid without spillage. A feed tank is connected to a liquid transfer jet powered by a pumping chamber pressurized by compressed air. The liquid is pumped upwardly into a sampling jet of a venturi design having a lumen with an inlet, an outlet, a constricted middle portion, and a port located above the constricted middle portion. The liquid is passed under pressure through the constricted portion causing its velocity to increase and its pressure to decreased, thereby preventing liquid from escaping. A septum sealing the port can be pierced by a two pointed hollow needle leading into a sample bottle also sealed by a pierceable septum affixed to one end. The bottle is evacuated by flow through the sample jet, cyclic variation in the sampler jet pressure periodically leaves the evacuated bottle with lower pressure than that of the port, thus causing solution to pass into the bottle. The remaining solution in the system is returned to the feed tank via a holding tank.

Houck, Edward D. (Idaho Falls, ID)

1994-01-01T23:59:59.000Z

159

Fluid sampling system  

DOE Patents (OSTI)

This invention comprises a fluid sampling system which allows sampling of radioactive liquid without spillage. A feed tank is connected to a liquid transfer jet powered by a pumping chamber pressurized by compressed air. The liquid is pumped up into a sampling jet of venturi design having a lumen with an inlet, an outlet, a constricted middle portion, and a port located above the constricted middle portion. The liquid is passed under pressure through the constricted portion causing its velocity to increase and its pressure to decrease, thereby preventing liquid from escaping. A septum sealing the port can be pierced by a two pointed hollow needle leading into a sample bottle also sealed by a pierceable septum affixed to one end. The bottle is evacuated by flow through the sample jet, cyclic variation in the sampler jet pressure periodicially leaves the evacuated bottle with lower pressure than that of the port, thus causing solution to pass into the bottle. The remaining solution in the system is returned to the feed tank via a holding tank.

Houck, E.D.

1993-12-31T23:59:59.000Z

160

Fluid sampling system  

DOE Patents (OSTI)

An fluid sampling system allows sampling of radioactive liquid without spillage. A feed tank is connected to a liquid transfer jet powered by a pumping chamber pressurized by compressed air. The liquid is pumped upwardly into a sampling jet of a venturi design having a lumen with an inlet, an outlet, a constricted middle portion, and a port located above the constricted middle portion. The liquid is passed under pressure through the constricted portion causing its velocity to increase and its pressure to be decreased, thereby preventing liquid from escaping. A septum sealing the port can be pierced by a two pointed hollow needle leading into a sample bottle also sealed by a pierceable septum affixed to one end. The bottle is evacuated by flow through the sample jet, cyclic variation in the sampler jet pressure periodically leaves the evacuated bottle with lower pressure than that of the port, thus causing solution to pass into the bottle. The remaining solution in the system is returned to the feed tank via a holding tank. 4 figs.

Houck, E.D.

1994-10-11T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Viscous sludge sample collector  

DOE Patents (OSTI)

A vertical core sample collection system for viscous sludge. A sample tube's upper end has a flange and is attached to a piston. The tube and piston are located in the upper end of a bore in a housing. The bore's lower end leads outside the housing and has an inwardly extending rim. Compressed gas, from a storage cylinder, is quickly introduced into the bore's upper end to rapidly accelerate the piston and tube down the bore. The lower end of the tube has a high sludge entering velocity to obtain a full-length sludge sample without disturbing strata detail. The tube's downward motion is stopped when its upper end flange impacts against the bore's lower end inwardly extending rim.

Beitel, George A. (Richland, WA)

1983-01-01T23:59:59.000Z

162

A Census of Mid-Infrared Selected Active Galactic Nuclei in Massive Galaxy Clusters at 0 < z < 1.3  

E-Print Network (OSTI)

We conduct a deep mid-infrared census of nine massive galaxy clusters at (0 = 3 sigma level, we identify 12 that host mid-infrared selected active galactic nuclei (IR-AGN). To compare the IR-AGN across our redshift range, we define two complete samples of cluster galaxies: (1) optically-selected members with rest-frame VAB magnitude 0.5 Mpc) and are hosted by highly morphologically disturbed members. Although our sample is limited, our results suggest that f_IR-AGN in massive galaxy clusters is not strongly correlated with star formation at z 1.

Tomczak, Adam 1987-

2012-12-01T23:59:59.000Z

163

MEASURING BULK FLOW OF GALAXY CLUSTERS USING KINEMATIC SUNYAEV-ZELDOVICH EFFECT: PREDICTION FOR PLANCK  

Science Conference Proceedings (OSTI)

We predict the performance of the Planck satellite in determining the bulk flow through kinetic Sunyaev-Zeldovich (kSZ) measurements. As velocity tracers, we use ROSAT All-Sky Survey (RASS) clusters as well as expected cluster catalogs from the upcoming missions Planck and eRosita (All-Sky Survey: EASS). We implement a semi-analytical approach to simulate realistic Planck maps as well as Planck and eRosita cluster catalogs. We adopt an unbiased kSZ filter (UF) and matched filter (MF) to maximize the cluster kSZ signal-to-noise ratio. We find that the use of Planck cosmic microwave background maps in conjunction with the currently existing ROSAT cluster sample improves current upper limits on the bulk flow determination by a factor {approx}5 ({approx}10) when using the MF (UF). The accuracy of bulk flow measurement increases with the depth and abundance of the cluster sample: for an input bulk velocity of 500 km s{sup -1}, the UF recovered velocity errors decrease from 94 km s{sup -1} for RASS, to 73 km s{sup -1} for Planck, and to 24 km s{sup -1} for EASS; while the systematic bias decreases from 44% for RASS, 5% for Planck, to 0% for EASS. The 95% upper limit for the recovered bulk flow direction {Delta}{alpha} ranges between 4{sup 0} and 60{sup 0} depending on cluster sample and adopted filter. The kSZ dipole determination is mainly limited by the effects of thermal SZ emission in all cases but the one of EASS clusters analyzed with the unbiased filter. This fact makes the UF preferable to the MF when analyzing Planck maps.

Mak, D. S. Y.; Pierpaoli, E. [Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484 (United States); Osborne, S. J. [Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), Stanford University, 382 Via Pueblo, Varian Building, Stanford, CA 94305 (United States)

2011-08-01T23:59:59.000Z

164

A study of the formation of cluster ions from metal acetates using plasma desorption mass spectrometry  

E-Print Network (OSTI)

A novel application of desorption/ionization methods of mass spectrometry, e. g. plasma desorption mass spectrometry (PDMS), is the analysis of both the composition and structure of solid materials in one experiment. Cluster ions emitted from the impact of a 252Cf fission fragment on a surface may represent a "view" of the solid construction over atomic distances if composed of atoms from adjacent sites in the surface. A clearer understanding of the mechanism of secondary cluster ion formation is necessary to evaluate the usefulness of PDMS as a surface characterization technique. The aim of this research was to use metal acetate samples to study secondary cluster ion formation in PDMS. In two sets of experiments, metal acetates from period IV and group IIB of the periodic table were used to measure the influence on cluster formation by the ground state electronic configuration and the ionic size, respectively, of the metal constituent. Relative yields for homologous negative and positive secondary cluster ions were determined and compared to thermochemical properties of the metal ion or the metal acetate molecule (AHf and lattice energy). Secondary ions in negative PDMS mass spectra attributable to a gas phase recombination formation mechanism follow trends predicted by these thermochemical properties. Another series of cluster ions, however, with the composition [M(Ac)2]Ac-(where Ac = acetate) does not follow the same trends, indicating possible formation via intact emission from the solid surface. Positive secondary cluster ions showed differences from the negative ions both in the relative yield distribution and the types of ions observed. Positive cluster ions from metal acetates from the fourth period of the periodic table were mainly metal oxides. On the other hand, positive clusters ions from the group IIB of the periodic table were mainly mirror images of the negative spectra. These differences suggest that the bonding characteristics of the metal ion play an important role in the secondary cluster ion formation process.

Mendez Silvagnoli, Winston Reinaldo

1995-01-01T23:59:59.000Z

165

Clues to Nuclear Star Cluster Formation from Edge-on Spirals  

E-Print Network (OSTI)

We find 9 nuclear cluster candidates in a sample of 14 edge-on, late-type galaxies observed with HST/ACS. These clusters have magnitudes (M_I ~ -11) and sizes (r_eff ~ 3pc) similar to those found in previous studies of face-on, late-type spirals and dE galaxies. However, three of the nuclear clusters are significantly flattened and show evidence for multiple, coincident structural components. The elongations of these three clusters are aligned to within 10 degrees of the galaxies' major axes. Structurally, the flattened clusters are well fit by a combination of a spheroid and a disk or ring. The nuclear cluster disks/rings have F606W-F814W (~V-I) colors 0.3-0.6 magnitudes bluer than the spheroid components, suggesting that the stars in these components have ages nuclear clusters, we further constrain the stellar populations and provide a lower limit on the dynamical mass via spectroscopy. We also present tentative evidence that another of the nuclear clusters (in NGC 4206) may also host a supermassive black hole. Based on our observational results we propose an in situ formation mechanism for nuclear clusters in which stars form episodically in compact nuclear disks, and then lose angular momentum or heat vertically to form an older spheroidal structure. We estimate the period between star formation episodes to be 0.5 Gyr and discuss possible mechanisms for tranforming the disk-like components into spheroids. We also note the connection between our objects and massive globular clusters (e.g. $\\omega$ Cen), UCDs, and SMBHs. (Abridged)

Anil C. Seth; Julianne J. Dalcanton; Paul W. Hodge; Victor P. Debattista

2006-09-11T23:59:59.000Z

166

ANNULAR IMPACTOR SAMPLING DEVICE  

DOE Patents (OSTI)

A high-rate air sampler capable of sampling alphaemitting particles as small as 0.5 microns is described. The device is a cylindrical shaped cup that fits in front of a suction tube and which has sticky grease coating along its base. Suction forces contaminated air against the periodically monitored particle absorbing grease.

Tait, G.W.C.

1959-03-31T23:59:59.000Z

167

RASS-SDSS Galaxy Cluster Survey. VI. The dependence of the cluster SFR on the cluster global properties  

E-Print Network (OSTI)

Using a subsample of 79 nearby clusters from the RASS-SDSS galaxy cluster catalogue of Popesso et al. (2005a), we perform a regression analysis between the cluster integrated star formation rate (Sigma_SFR) the cluster total stellar mass (M_star), the fractions of star forming (f_SF) and blue (f_b) galaxies and other cluster global properties, namely its richness (N_gal, i.e. the total number of cluster members within the cluster virial radius), velocity dispersion (sigma_v), virial mass (M_200), and X-ray luminosity (L_X). All cluster global quantities are corrected for projection effects before the analysis. Galaxy SFRs and stellar masses are taken from the catalog of Brinchmann et al. (2004), which is based on SDSS spectra. We only consider galaxies with M_r analysis, and exclude AGNs. We find that both Sigma_SFR and M_star are correlated with all the cluster global quantities. A partial correlation analysis show that all the correlations are induced by the fundamental one between Sigma_SFR and N_gal, hence there is no evidence that the cluster properties affect the mean SFR or M_star per galaxy. The relations between Sigma_SFR and M_star, on one side, and both N_gal and M_200, on the other side, are linear, i.e. we see no evidence that different clusters have different SFR or different M_star per galaxy and per unit mass. The fraction f_SF does not depend on any cluster property considered, while f_b does depend on L_X. We note that a significant fraction of star-forming cluster galaxies are red (~25% of the whole cluster galaxy population). We conclude that the global cluster properties are unable to affect the SF properties of cluster galaxies, but the presence of the X-ray luminous intra-cluster medium can affect their colors, perhaps through the ram-pressure stripping mechanism.

P. Popesso; A. Biviano; M. Romaniello; H. Böhringer

2006-09-04T23:59:59.000Z

168

THE SIZE SCALE OF STAR CLUSTERS  

SciTech Connect

Direct N-body simulations of star clusters in a realistic Milky-Way-like potential are carried out using the code NBODY6. Based on these simulations, a new relationship between scale size and galactocentric distance is derived: the scale size of star clusters is proportional to the hyperbolic tangent of the galactocentric distance. The half-mass radius of star clusters increases systematically with galactocentric distance but levels off when star clusters orbit the galaxy beyond {approx}40 kpc. These simulations show that the half-mass radius of individual star clusters varies significantly as they evolve over a Hubble time, more so for clusters with shorter relaxation times, and remains constant through several relaxation times only in certain situations when expansion driven by the internal dynamics of the star cluster and the influence of the host galaxy tidal field balance each other. Indeed, the radius of a star cluster evolving within the inner 20 kpc of a realistic galactic gravitational potential is severely truncated by tidal interactions and does not remain constant over a Hubble time. Furthermore, the half-mass radius of star clusters measured with present-day observations bears no memory of the original cluster size. Stellar evolution and tidal stripping are the two competing physical mechanisms that determine the present-day size of globular clusters. These simulations also show that extended star clusters can form at large galactocentric distances while remaining fully bound to the host galaxy. There is thus no need to invoke accretion from an external galaxy to explain the presence of extended clusters at large galactocentric distances in a Milky-Way-type galaxy.

Madrid, Juan P.; Hurley, Jarrod R.; Sippel, Anna C. [Center for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, VIC 3122 (Australia)

2012-09-10T23:59:59.000Z

169

THE DYNAMICS OF MERGING CLUSTERS: A MONTE CARLO SOLUTION APPLIED TO THE BULLET AND MUSKET BALL CLUSTERS  

SciTech Connect

Merging galaxy clusters have become one of the most important probes of dark matter, providing evidence for dark matter over modified gravity and even constraints on the dark matter self-interaction cross-section. To properly constrain the dark matter cross-section it is necessary to understand the dynamics of the merger, as the inferred cross-section is a function of both the velocity of the collision and the observed time since collision. While the best understanding of merging system dynamics comes from N-body simulations, these are computationally intensive and often explore only a limited volume of the merger phase space allowed by observed parameter uncertainty. Simple analytic models exist but the assumptions of these methods invalidate their results near the collision time, plus error propagation of the highly correlated merger parameters is unfeasible. To address these weaknesses I develop a Monte Carlo method to discern the properties of dissociative mergers and propagate the uncertainty of the measured cluster parameters in an accurate and Bayesian manner. I introduce this method, verify it against an existing hydrodynamic N-body simulation, and apply it to two known dissociative mergers: 1ES 0657-558 (Bullet Cluster) and DLSCL J0916.2+2951 (Musket Ball Cluster). I find that this method surpasses existing analytic models-providing accurate (10% level) dynamic parameter and uncertainty estimates throughout the merger history. This, coupled with minimal required a priori information (subcluster mass, redshift, and projected separation) and relatively fast computation ({approx}6 CPU hours), makes this method ideal for large samples of dissociative merging clusters.

Dawson, William A., E-mail: wadawson@ucdavis.edu [Physics Department, University of California, Davis, One Shields Avenue, Davis, CA 95616 (United States)

2013-08-01T23:59:59.000Z

170

ITOUGH2 sample problems  

DOE Green Energy (OSTI)

This report contains a collection of ITOUGH2 sample problems. It complements the ITOUGH2 User`s Guide [Finsterle, 1997a], and the ITOUGH2 Command Reference [Finsterle, 1997b]. ITOUGH2 is a program for parameter estimation, sensitivity analysis, and uncertainty propagation analysis. It is based on the TOUGH2 simulator for non-isothermal multiphase flow in fractured and porous media [Preuss, 1987, 1991a]. The report ITOUGH2 User`s Guide [Finsterle, 1997a] describes the inverse modeling framework and provides the theoretical background. The report ITOUGH2 Command Reference [Finsterle, 1997b] contains the syntax of all ITOUGH2 commands. This report describes a variety of sample problems solved by ITOUGH2. Table 1.1 contains a short description of the seven sample problems discussed in this report. The TOUGH2 equation-of-state (EOS) module that needs to be linked to ITOUGH2 is also indicated. Each sample problem focuses on a few selected issues shown in Table 1.2. ITOUGH2 input features and the usage of program options are described. Furthermore, interpretations of selected inverse modeling results are given. Problem 1 is a multipart tutorial, describing basic ITOUGH2 input files for the main ITOUGH2 application modes; no interpretation of results is given. Problem 2 focuses on non-uniqueness, residual analysis, and correlation structure. Problem 3 illustrates a variety of parameter and observation types, and describes parameter selection strategies. Problem 4 compares the performance of minimization algorithms and discusses model identification. Problem 5 explains how to set up a combined inversion of steady-state and transient data. Problem 6 provides a detailed residual and error analysis. Finally, Problem 7 illustrates how the estimation of model-related parameters may help compensate for errors in that model.

Finsterle, S.

1997-11-01T23:59:59.000Z

171

Formation of Globular Clusters in Galaxy Mergers  

E-Print Network (OSTI)

We present a high-resolution simulation of globular cluster formation in a galaxy merger. For the first time in such a simulation, individual star clusters are directly identified and followed on their orbits. We quantitatively compare star formation in the merger to that in the unperturbed galaxies. The merging galaxies show a strong starburst, in sharp contrast to their isolated progenitors. Most star clusters form in the tidal features. With a mass range of $5\\times10^{5}$--$5\\times 10^{6} M_{\\odot}$, they are identified as globular clusters. The merger remnant is an elliptical galaxy. Clusters with different mass or age have different radial distributions in the galaxy. Our results show that the high specific frequency and bimodal distribution of metallicity observed in elliptical galaxies are natural products of gas-rich mergers, supporting a merger origin for the ellipticals and their globular cluster systems.

Yuexing Li; Mordecai-Mark Mac Low; Ralf S. Klessen

2004-07-13T23:59:59.000Z

172

The Lx-Yx Relation: Using Galaxy Cluster X-Ray Luminosity as a Robust, Low Scatter Mass Proxy  

E-Print Network (OSTI)

We use a sample of 115 galaxy clusters at 0.1cluster cores, and a tight LY relation (11% intrinsic scatter in Lx) is recovered if sufficiently large core regions (0.15R500) are excluded. The intrinsic scatter is well described by a lognormal distribution and the relations are consistent for relaxed and disturbed/merging clusters. We investigate the LY relation in low-quality data (e.g. for clusters detected in X-ray survey data) by estimating Lx from soft band count rates, and find that the scatter increases somewhat to 21%. We confirm the tight correlation between Yx and mass and the self-similar evolution of that scaling relation out to z=0.6 for a subset of clusters in our sample with mass estimates from the literature. This is used to estimate masses for the entire sample and hence measure the LM relation. We find that the scatter in the LM relation is much lower than previous estimates, due to the full removal of cluster cores and more robust mass estimates. For high-redshift clusters the scatter in the LM relation remains low if cluster cores are not excluded. These results suggest that cluster masses can be reliably estimated from simple luminosity measurements in low quality data where direct mass estimates, or measurements of Yx are not possible. This has important applications in the estimation of cosmological parameters from X-ray cluster surveys.

B. J. Maughan

2007-03-19T23:59:59.000Z

173

Overlapping clusters for distributed computation.  

SciTech Connect

Scalable, distributed algorithms must address communication problems. We investigate overlapping clusters, or vertex partitions that intersect, for graph computations. This setup stores more of the graph than required but then affords the ease of implementation of vertex partitioned algorithms. Our hope is that this technique allows us to reduce communication in a computation on a distributed graph. The motivation above draws on recent work in communication avoiding algorithms. Mohiyuddin et al. (SC09) design a matrix-powers kernel that gives rise to an overlapping partition. Fritzsche et al. (CSC2009) develop an overlapping clustering for a Schwarz method. Both techniques extend an initial partitioning with overlap. Our procedure generates overlap directly. Indeed, Schwarz methods are commonly used to capitalize on overlap. Elsewhere, overlapping communities (Ahn et al, Nature 2009; Mishra et al. WAW2007) are now a popular model of structure in social networks. These have long been studied in statistics (Cole and Wishart, CompJ 1970). We present two types of results: (i) an estimated swapping probability {rho}{infinity}; and (ii) the communication volume of a parallel PageRank solution (link-following {alpha} = 0.85) using an additive Schwarz method. The volume ratio is the amount of extra storage for the overlap (2 means we store the graph twice). Below, as the ratio increases, the swapping probability and PageRank communication volume decreases.

Mirrokni, Vahab (Google Research, New York, NY); Andersen, Reid (Microsoft Corporation, Redmond, WA); Gleich, David F.

2010-11-01T23:59:59.000Z

174

Nuclear Star Clusters - Structure and Stellar Populations  

E-Print Network (OSTI)

This is an overview of nuclear star cluster observations, covering their structure, stellar populations, kinematics and possible connection to black holes at the centers of galaxies.

Neumayer, Nadine

2012-01-01T23:59:59.000Z

175

NCNR Magnetic Cluster Sizes in Recording Disks  

Science Conference Proceedings (OSTI)

... Presently, cluster sizes are believed to be about 10 nano meters to 15 nano meters, but accurate knowledge of the size distribution and even the ...

176

Non thermal emission in clusters of galaxies  

E-Print Network (OSTI)

I briefly review our current knowledge of the non thermal emission from galaxy clusters and discuss future prospect with Simbol-X. Simbol-X will map the hard X-ray emission in clusters, determine its origin and disentangle the thermal and non-thermal components. Correlated with radio observations, the observation of the non-thermal X-ray emission, when confirmed, will allow to map both the magnetic field and the relativistic electron properties, key information to understand the origin and acceleration of relativistic particles in clusters and its impact on cluster evolution.

Arnaud, M

2008-01-01T23:59:59.000Z

177

Unsupervised clustering and centroid estimation using dynamic ...  

Science Conference Proceedings (OSTI)

solving cluster detection and centroid estimation prob- lems. ... density function and these vectors estimate the cen- ..... an algorithm to minimize a cost function.

178

Nanostructured manganese oxide clusters supported on ...  

2 evolution at nano-structured Mn oxide clusters in mesoporous silica under very mild conditions for the ?rst time. For driving the catalyst with

179

NID Copper Sample Analysis  

SciTech Connect

The current focal point of the nuclear physics program at PNNL is the MAJORANA DEMONSTRATOR, and the follow-on Tonne-Scale experiment, a large array of ultra-low background high-purity germanium detectors, enriched in 76Ge, designed to search for zero-neutrino double-beta decay (0???). This experiment requires the use of germanium isotopically enriched in 76Ge. The MAJORANA DEMONSTRATOR is a DOE and NSF funded project with a major science impact. The DEMONSTRATOR will utilize 76Ge from Russia, but for the Tonne-Scale experiment it is hoped that an alternate technology, possibly one under development at Nonlinear Ion Dynamics (NID), will be a viable, US-based, lower-cost source of separated material. Samples of separated material from NID require analysis to determine the isotopic distribution and impurities. DOE is funding NID through an SBIR grant for development of their separation technology for application to the Tonne-Scale experiment. The Environmental Molecular Sciences facility (EMSL), a DOE user facility at PNNL, has the required mass spectroscopy instruments for making isotopic measurements that are essential to the quality assurance for the MAJORANA DEMONSTRATOR and for the development of the future separation technology required for the Tonne-Scale experiment. A sample of isotopically separated copper was provided by NID to PNNL in January 2011 for isotopic analysis as a test of the NID technology. The results of that analysis are reported here. A second sample of isotopically separated copper was provided by NID to PNNL in August 2011 for isotopic analysis as a test of the NID technology. The results of that analysis are also reported here.

Kouzes, Richard T.; Zhu, Zihua

2011-09-12T23:59:59.000Z

180

NID Copper Sample Analysis  

Science Conference Proceedings (OSTI)

The current focal point of the nuclear physics program at PNNL is the MAJORANA DEMONSTRATOR, and the follow-on Tonne-Scale experiment, a large array of ultra-low background high-purity germanium detectors, enriched in 76Ge, designed to search for zero-neutrino double-beta decay (0???). This experiment requires the use of germanium isotopically enriched in 76Ge. The DEMONSTRATOR will utilize 76Ge from Russia, but for the Tonne-Scale experiment it is hoped that an alternate technology under development at Nonlinear Ion Dynamics (NID) will be a viable, US-based, lower-cost source of separated material. Samples of separated material from NID require analysis to determine the isotopic distribution and impurities. The MAJORANA DEMONSTRATOR is a DOE and NSF funded project with a major science impact. DOE is funding NID through an SBIR grant for development of their separation technology for application to the Tonne-Scale experiment. The Environmental Molecular Sciences facility (EMSL), a DOE user facility at PNNL, has the required mass spectroscopy instruments for making these isotopic measurements that are essential to the quality assurance for the MAJORANA DEMONSTRATOR and for the development of the future separation technology required for the Tonne-Scale experiment. A sample of isotopically separated copper was provided by NID to PNNL for isotopic analysis as a test of the NID technology. The results of that analysis are reported here.

Kouzes, Richard T.; Zhu, Zihua

2011-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Incremental spectral clustering by efficiently updating the eigen-system  

Science Conference Proceedings (OSTI)

In recent years, the spectral clustering method has gained attentions because of its superior performance. To the best of our knowledge, the existing spectral clustering algorithms cannot incrementally update the clustering results given a small change ... Keywords: Graph, Incidence vector/matrix, Incremental clustering, Spectral clustering, Web-blogs

Huazhong Ning; Wei Xu; Yun Chi; Yihong Gong; Thomas S. Huang

2010-01-01T23:59:59.000Z

182

Fluid sampling apparatus and method  

DOE Patents (OSTI)

Incorporation of a bellows in a sampling syringe eliminates ingress of contaminants, permits replication of amounts and compression of multiple sample injections, and enables remote sampling for off-site analysis.

Yeamans, David R. (Los Alamos, NM)

1998-01-01T23:59:59.000Z

183

Decoupled Sampling for Graphics Pipelines  

E-Print Network (OSTI)

We propose a generalized approach to decoupling shading from visibility sampling in graphics pipelines, which we call decoupled sampling. Decoupled sampling enables stochastic supersampling of motion and defocus blur at ...

Ragan-Kelley, Jonathan Millar

184

PDSF, NERSC's Physics Computing Cluster  

NLE Websites -- All DOE Office Websites (Extended Search)

PDSF PDSF PDSF PDSF is a networked distributed computing cluster designed primarily to meet the detector simulation and data analysis requirements of physics, astrophysics and nuclear science collaborations. For more details see About PDSF. Click on the graphs below to see larger versions and longer term graphs. Running Jobs Pending Jobs 24 hour rolling usage graph Rolling 24 Pending Jobs by Group About Find out more about PDSF, including a general overview, and information about research groups and staff... Read More » PDSF Login Node Status Getting Started Guidance on obtaining a new user account, access, passwords, and setup files... Read More » Hardware Configuration Provides guidance on hardware configurations, including: login, compute, grid and transfer nodes, and working with particular file systems.

185

THREE-CLUSTER NUCLEAR MOLECULES  

E-Print Network (OSTI)

A three-center phenomenological model able to explain, at least from a qualitative point of view, the difference in the observed yield of a particle-accompanied fission and that of binary fission was developed. It is derived from the liquid drop model under the assumption that the aligned configuration, with the emitted particle between the light and heavy fragment is obtained by increasing continuously the separation distance, while the radii of the light fragment and of the light particle are kept constant. During the first stage of the deformation one has a two-center evolution until the neck radius becomes equal to the radius of the emitted particle. Then the three center starts developing by decreasing with the same amount the two tip distances. In such a way a second minimum, typical for a cluster molecule, appears in the deformation energy. Examples are presented for 240 Pu parent nucleus emitting ?-particles and 14 C in a ternary process. 1

D. N. Poenaru; B. Dobrescu; W. Greiner

2000-01-01T23:59:59.000Z

186

Bimodal Galaxies and Bimodality in Globular Cluster Systems  

E-Print Network (OSTI)

Various galaxy properties are not continuous over a large range in mass, but rather reveal a remarkable transition or `bimodality' at a stellar mass of 3 x 10^{10} Mo. These properties include colors, stellar populations, Xray emission and mass-to-light ratios. This behavior has been interpreted as the transition from hot to cold flows by Dekel & Birnboim (2005). Here we explore whether globular cluster (GC) systems also reveal a bimodal nature with regard to this critical mass scale. Globular clusters probe star formation at early epochs in the Universe and survive subsequent galaxy mergers and accretions. We use new data from the ACS Virgo Cluster Survey (Peng etal 2005), which provides a homogeneous sample of the GC systems around one hundred Virgo early-type galaxies covering a range of five hundred in galaxy mass. Their classification of the GC color distributions is taken to examine a key quantity -- the number of GCs per unit galaxy luminosity. Below the critical mass, this quantity (called the GC specific frequency) increases dramatically in its mean value and spread. This increase may be due to regulated star formation in low mass galaxies, which in turn is due to mass loss via winds and the transition from hot to cold gas accretion flows. We also note that above the critical mass, galaxies possess two GC subpopulations (with blue and red mean colors) but below this mass, galaxies reveal an increasing proportion of single (blue) GC systems.

Duncan A. Forbes

2005-11-10T23:59:59.000Z

187

Completion report for Well Cluster ER-20-5  

SciTech Connect

The Well Cluster ER-20-5 drilling and completion project was conducted for the US Department of Energy, Nevada Operations Office (DOE/NV), in support of the Nevada Environmental Restoration Project at the Nevada Test Site (NTS) in Nye County, Nevada. Its primary tasks include collecting geological, geophysical, hydrological, and water chemistry data from new and existing wells to define groundwater quality in addition to pathways and rates of groundwater migration. A program of drilling wells near the sites of selected underground nuclear tests (near-field drilling) was implemented to obtain site-specific data about the nature and extent of migration of radionuclides that might have been produced by an underground nuclear explosion. Well Cluster ER-20-5 is the first near-field drilling project initiated at the NTS. This document presents construction data and summarizes the scientific data gathered during the drilling and well-installation phases for all three holes drilled at Well Cluster ER-20-5. Some of this information is preliminary and unprocessed, but was released so that drilling, geotechnical, well design, and completion data could be rapidly disseminated. Additional information about water levels, aquifer testing, and groundwater sampling will be reported after any of this work is performed. Any additional geologic and/or geophysical investigations conducted for this project is described in one or more analysis and interpretation reports. The lithologic and stratigraphic logs, however, are provided in final form.

NONE

1997-03-01T23:59:59.000Z

188

2009 Clusters, Nanocrystals & Nanostructures GRC  

SciTech Connect

For over thirty years, this Gordon Conference has been the premiere meeting for the field of cluster science, which studies the phenomena that arise when matter becomes small. During its history, participants have witnessed the discovery and development of many novel materials, including C60, carbon nanotubes, semiconductor and metal nanocrystals, and nanowires. In addition to addressing fundamental scientific questions related to these materials, the meeting has always included a discussion of their potential applications. Consequently, this conference has played a critical role in the birth and growth of nanoscience and engineering. The goal of the 2009 Gordon Conference is to continue the forward-looking tradition of this meeting and discuss the most recent advances in the field of clusters, nanocrystals, and nanostructures. As in past meetings, this will include new topics that broaden the field. In particular, a special emphasis will be placed on nanomaterials related to the efficient use, generation, or conversion of energy. For example, we anticipate presentations related to batteries, catalysts, photovoltaics, and thermoelectrics. In addition, we expect to address the controversy surrounding carrier multiplication with a session in which recent results addressing this phenomenon will be discussed and debated. The atmosphere of the conference, which emphasizes the presentation of unpublished results and lengthy discussion periods, ensures that attendees will enjoy a valuable and stimulating experience. Because only a limited number of participants are allowed to attend this conference, and oversubscription is anticipated, we encourage all interested researchers from academia, industry, and government institutions to apply as early as possible. An invitation is not required. We also encourage all attendees to submit their latest results for presentation at the poster sessions. We anticipate that several posters will be selected for 'hot topic' oral presentations. Because of the important role that students and postdocs play in the future of this field, we also anticipate to select several posters from young investigators for oral presentations.

Lai-Sheng Wang

2009-07-19T23:59:59.000Z

189

Catching Dissolving Clusters: a New Approach  

E-Print Network (OSTI)

Traditional studies of stellar clusters in external galaxies use surface photometry and therefore focus on systems that are still bright and compact enough to be separated from the stellar background. Consequently, the latter stages of unbound cluster evolution are still poorly understood. This dramatically constrains our knowledge of the dissolution processes of stellar clusters in various physical environments. We present the first results of a new approach to directly detect and quantify the characteristics of evolved stellar clusters. Using the exceptional spatial resolution and sensitivity of HST/ACS images to resolve the stellar content nearby galaxies, we construct colour-magnitude diagrams for the observed fields. This enable us to separate the younger population likely present in young clusters from the older stellar content of the star field background. We utilize a clustering algorithm to assign each star to a group based on its local spatial density. This novel approach makes use of algorithms typically applied in N-body and cosmological studies. We test the method and show that it successfully detects less compact clusters that would normally be lost in the star field background. We also detect B-type stars well spread in the galaxy disk of NGC 1313, probably the result of infant mortality of stellar clusters.

Anne Pellerin; Martin Meyer; Jason Harris; Daniela Calzetti

2006-10-26T23:59:59.000Z

190

Clustering techniques for open relation extraction  

Science Conference Proceedings (OSTI)

This work investigates clustering techniques for Relation Extraction (RE). Relation Extraction is the task of extracting relationships among named entities (e.g., people, organizations and geo-political entities) from natural language text. We are particularly ... Keywords: relation extraction, text clustering

Filipe Mesquita

2012-05-01T23:59:59.000Z

191

Clustering High Dimensional Massive Scientific Datasets  

Science Conference Proceedings (OSTI)

Many scientific applications can benefit from an efficient clustering algorithm of massively large high dimensional datasets. However most of the developed algorithms are impractical to use when the amount of data is very large. Given N objects ... Keywords: clustering, datasets, high dimensional, scientific

Ekow J. Otoo; Arie Shoshani; Seung-Won Hwang

2001-12-01T23:59:59.000Z

192

The multidimensional model of cluster radioactivity  

E-Print Network (OSTI)

The cluster decays $^{228}$Th $\\rightarrow \\, ^{208}$Pb + $^{20}$O, $^{232}$U $\\rightarrow \\, ^{208}$Pb + $^{24}$Ne, $^{236}$Pu $\\rightarrow \\, ^{208}$Pb + $^{28}$Mg, $^{242}$Cm $\\rightarrow \\, ^{208}$Pb + $^{34}$Si are considered in the framework of the multidimensional cluster preformation model. The macroscopic potential energy surface related to the interaction between the cluster and the residue nucleus is evaluated in the framework of the nonlocal $\\hbar^4$ extended Thomas-Fermi approach with Skyrme and Coulomb forces. The shell-correction to the macroscopic potential energy is also taken into account. The dynamical surface deformations of both the cluster and the residue nucleus are taken into consideration at the barrier penetration path. The heights of saddle points related to deformed nuclear shapes are lower than the barrier height between the spherical cluster and residue nuclei; therefore the dynamical deformations of nuclei increase the barrier penetrability and reduce the half-life of cluster decay. The shell correction contribution into the potential energy between cluster and residue nucleus is important for both the potential landscape and the half-life evaluation. The experimental values of cluster decay half-lives are well reproduced in the model.

V. Yu. Denisov

2013-11-15T23:59:59.000Z

193

Clustering objects on a spatial network  

Science Conference Proceedings (OSTI)

Clustering is one of the most important analysis tasks in spatial databases. We study the problem of clustering objects, which lie on edges of a large weighted spatial network. The distance between two objects is defined by their shortest path distance ...

Man Lung Yiu; Nikos Mamoulis

2004-06-01T23:59:59.000Z

194

Groundwater Sampling | Open Energy Information  

Open Energy Info (EERE)

Groundwater Sampling Groundwater Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Groundwater Sampling Details Activities (3) Areas (2) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Field Sampling Parent Exploration Technique: Water Sampling Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Water composition and source of fluids. Determination of mixing ratios between different fluid end-members. Determination of fluid recharge rates and residence times. Thermal: Water temperature. Dictionary.png Groundwater Sampling: Groundwater sampling is done to characterize the chemical, thermal, or hydrological properties of subsurface aqueous systems. Groundwater sampling

195

Water Sampling | Open Energy Information  

Open Energy Info (EERE)

Water Sampling Water Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Water Sampling Details Activities (51) Areas (45) Regions (5) NEPA(2) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Field Sampling Parent Exploration Technique: Field Sampling Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Water composition and source of fluids Thermal: Water temperature Dictionary.png Water Sampling: Water sampling is done to characterize the chemical, thermal, or hydrological properties of a surface or subsurface aqueous system. Other definitions:Wikipedia Reegle Introduction Water sampling is done to characterize the geothermal system under investigation. A geothermal water typically has a unique chemical signature

196

Sample holder with optical features  

DOE Patents (OSTI)

A sample holder for holding a sample to be observed for research purposes, particularly in a transmission electron microscope (TEM), generally includes an external alignment part for directing a light beam in a predetermined beam direction, a sample holder body in optical communication with the external alignment part and a sample support member disposed at a distal end of the sample holder body opposite the external alignment part for holding a sample to be analyzed. The sample holder body defines an internal conduit for the light beam and the sample support member includes a light beam positioner for directing the light beam between the sample holder body and the sample held by the sample support member.

Milas, Mirko; Zhu, Yimei; Rameau, Jonathan David

2013-07-30T23:59:59.000Z

197

A faint galaxy redshift survey behind massive clusters  

SciTech Connect

This thesis is concerned with the gravitational lensing effect by massive galaxy clusters. We have explored a new technique for measuring galaxy masses and for detecting high-z galaxies by their optical colors. A redshift survey has been obtained at the Keck for a magnitude limited sample of objects (I<23) behind three clusters, A1689, A2390, and A2218 within a radius of 0.5M pc. For each cluster we see both a clear trend of increasing flux and redshift towards the center. This behavior is the result of image magnifications, such that at fixed redshift one sees further down the luminosity function. The gradient of this magnification is, unlike measurements of image distortion, sensitive to the mass profile, and found to depart strongly from a pure isothermal halo. We have found that V RI color selection can be used effectively as a discriminant for finding high-z galaxies behind clusters and present five 4.1 < z < 5.1 spectra which are of very high quality due to their high mean magnification of {approximately}20, showing strong, visibly-saturated interstellar metal lines in some cases. We have also investigated the radio ring lens PKS 1830-211, locating the source and multiple images and detected molecular absorption at mm wavelengths. Broad molecular absorption of width 1/40kms is found toward the southwest component only, where surprisingly it does not reach the base of the continuum, which implies incomplete coverage of the SW component by molecular gas, despite the small projected size of the source, less than 1/8h pc at the absorption redshift.

Frye, Brenda

1999-12-01T23:59:59.000Z

198

3D human posture segmentation by spectral clustering with surface normal constraint  

Science Conference Proceedings (OSTI)

In this paper, we propose a new algorithm for partitioning human posture represented by 3D point clouds sampled from the surface of human body. The algorithm is formed as a constrained extension of the recently developed segmentation method, spectral ... Keywords: 3D human posture segmentation, Constrained spectral clustering

Jun Cheng; Maoying Qiao; Wei Bian; Dacheng Tao

2011-09-01T23:59:59.000Z

199

Knowledge-based cluster development in India : opportunities and challenges  

E-Print Network (OSTI)

Knowledge-based industries tend to cluster. The nature of activities illustrate the importance of networks and virtual and proximity aspects of clustering. Review of existing literature brings out the advantages of clustering ...

Singla, Chandan Dev

2008-01-01T23:59:59.000Z

200

Distilling relevant documents by means of dynamic quantum clustering  

Science Conference Proceedings (OSTI)

Dynamic Quantum Clustering (DQC) is a recent clustering technique based on physical intuition from quantum mechanics. Clusters are identified as the minima of the potential function of the Schrödinger equation. In this poster, we apply this technique ...

Emanuele Di Buccio; Giorgio Maria Di Nunzio

2011-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Power management for heterogeneous clusters: An experimental study  

Science Conference Proceedings (OSTI)

Reducing energy consumption has a significant role in mitigating the total cost of ownership of computing clusters. Building heterogeneous clusters by combining high-end and low-end server nodes (e.g., Xeons and Atoms) is a recent trend towards achieving ... Keywords: Web server cluster, power management, heterogeneous cluster, energy consumption, high-end server nodes, low-end server nodes, Xeons, Atoms, energy-efficient computing, cluster-level power manager, optimal cluster configuration

M. Mustafa Rafique; Nishkam Ravi; Srihari Cadambi; Ali R. Butt; Srimat Chakradhar

2011-07-01T23:59:59.000Z

202

Sampling streaming data with replacement  

Science Conference Proceedings (OSTI)

Simple random sampling is a widely accepted basis for estimation from a population. When data come as a stream, the total population size continuously grows and only one pass through the data is possible. Reservoir sampling is a method of maintaining ... Keywords: Data stream mining, Random sampling with replacement, Reservoir sampling

Byung-Hoon Park; George Ostrouchov; Nagiza F. Samatova

2007-10-01T23:59:59.000Z

203

Probing the Birth of Super Star Clusters: Implications for Massive Star Formation  

E-Print Network (OSTI)

Super Star Clusters are one of the most extreme star forming environments in the universe, and the most massive and dense of these may be proto globular clusters. Like individual massive stars, the earliest stages of super star cluster evolution are deeply obscured, and therefore our knowledge about their birth environments is currently very incomplete. However, the study of natal super star clusters has become somewhat of a cottage industry in recent years, and the sample of such objects has been growing rapidly with high-quality long-wavelength data now available from a number of observatories. The natal super star clusters identified in thermal-infrared and radio observations represent the youngest stage of massive star cluster evolution yet observed. Their properties appear to be similar to those of ultracompact HII regions in the Milky Way, but scaled up in total mass and luminosity. I will overview what we think we know about these objects based on existing observations, discuss their relationship to ultracompact HII regions, present new models of their spectral energy distributions based on 3-D simulations, and outline some of the most significant gaps in our current understanding.

Kelsey E. Johnson

2005-06-21T23:59:59.000Z

204

Gas Sampling | Open Energy Information  

Open Energy Info (EERE)

Gas Sampling Gas Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Gas Sampling Details Activities (7) Areas (7) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Field Sampling Parent Exploration Technique: Field Sampling Information Provided by Technique Lithology: Stratigraphic/Structural: High flux can be indicative of conduits for fluid flow. Hydrological: Gas composition and source of fluids. Thermal: Anomalous flux is associated with active hydrothermal activity. Distinguish magmatic/mantle heat inputs. Can be used to estimate reservoir fluid temperatures. Dictionary.png Gas Sampling: Gas sampling is done to characterize the chemical, thermal, and hydrological properties of a surface or subsurface hydrothermal system.

205

No Evidence for Gamma-Ray Burst/Abell Cluster or Gamma- Ray Burst/Radio-Quiet Quasar Correlations  

E-Print Network (OSTI)

We examine the recent claims that cosmic gamma-ray bursts are associated with either radio-quiet quasars or Abell clusters. These associations were based on positional coincidences between cataloged quasars or Abell clusters, and selected events from the BATSE 3B catalog of gamma-ray bursts. We use a larger sample of gamma-ray bursts with more accurate positions, obtained by the 3rd Interplanetary Network, to re-evaluate these possible associations. We find no evidence for either.

K. Hurley; D. H. Hartmann; C. Kouveliotou; R. M. Kippen; J. Laros; T. Cline; M. Boer

1998-11-28T23:59:59.000Z

206

Cluster catalyzed chemisorption of H2 on Si(111)(1×1): Effects of collision speed and cluster geometry  

Science Conference Proceedings (OSTI)

We have carried out classical dynamical simulations of collisions of Ar12H2clusters with a rigid Si(111)(1×1) solid surface for a variety of collision speeds and two different cluster geometries. At low cluster temperatures

John N. Beauregard; Howard R. Mayne

1993-01-01T23:59:59.000Z

207

Rotation and chemical abundances of Ap/Bp stars in the open cluster NGC 6475  

E-Print Network (OSTI)

The connection between age, rotation and chemical abundance of magnetic Ap stars is poorly understood. Using open clusters, we are able to study samples of stars that are both co-eval and co-environmental. By determining rotation and chemical abundance for Ap star members of clusters with various ages, the variations of these properties as a function of age and environment can be derived. All four probable Ap star members of the open cluster NGC 6475, as well as one normal late B star, were studied using detailed spectrum synthesis of high resolution UVES-POP spectra. Probable cluster membership was confirmed for all five stars, however chemical abundance anomalies only appear to be present in spectra of three. Projected rotational velocity and chemical abundances for 21 elements ranging from C to Eu are presented for the 5 stars. In the three peculiar stars we find overabundances of Si, Cr, Mn, Fe and rare earths such as Nd, characteristic of Ap stars. The set of chemically peculiar stars show fairly homogeneous abundance tables, however notable differences exist for a few elements. There also exist appreciable differences in the v sin i and main sequence evolutionary stage of the chemically peculiar stars. This may hint at the underlying processes giving rise to the observed abundance anomalies. With this first detailed study of chemical abundances of a complete sample of magnetic Ap/Bp stars in an open cluster, we have initiated an exploration of the environmental and evolutionary influence on chemical peculiarity.

C. P. Folsom; G. A. Wade; S. Bagnulo; J. D. Landstreet

2006-12-11T23:59:59.000Z

208

Clustering of scientific citations in Wikipedia Finn Arup Nielsen  

E-Print Network (OSTI)

Cluster Numberofclusters Cluster bush List of molecul Extinction (ast Supernova Gamma ray burst List of molecul Extinction (ast Supernova Gamma ray burst Myocardial infa History of inva

209

Approximating K-means-type clustering via semidefinite programming  

E-Print Network (OSTI)

One of the fundamental clustering problems is to assign n points into k clusters based on the ...... In N. Ye, Editor, The Handbook of Data Mining, Lawrence ...

210

Clustered DNA Damage Spectrum in Primary Human Hematopoietic...  

NLE Websites -- All DOE Office Websites (Extended Search)

94805 Villejuif Cedex France Clustered DNA Damages Induced by Low Radiation Doses Irradiation of cells with low doses of X- or -rays induces clustered damages in mammalian...

211

High performance computing: Clusters, constellations, MPPs, and future directions  

E-Print Network (OSTI)

and Jim Gray, “High Performance Computing: Crays, Clusters,The Marketplace of High-Performance Computing”, ParallelHigh Performance Computing Clusters, Constellations, MPPs,

Dongarra, Jack; Sterling, Thomas; Simon, Horst; Strohmaier, Erich

2003-01-01T23:59:59.000Z

212

Computer System, Cluster, and Networking Summer Institute Program...  

NLE Websites -- All DOE Office Websites (Extended Search)

System, Cluster, and Networking Summer Institute Program Description The Computer System, Cluster, and Networking Summer Institute (CSCNSI) is a focused technical enrichment...

213

A MULTI-WAVELENGTH STUDY OF LOW-REDSHIFT CLUSTERS OF GALAXIES. II. ENVIRONMENTAL IMPACT ON GALAXY GROWTH  

Science Conference Proceedings (OSTI)

Galaxy clusters provide powerful laboratories for the study of galaxy evolution, particularly the origin of correlations of morphology and star formation rate (SFR) with density. We construct visible to MIR spectral energy distributions of galaxies in eight low-redshift (z 99% confidence) with no dependence on R/R{sub 200} or projected local density at fixed mass. A merged sample of galaxies from the five best measured clusters shows (SFR){proportional_to}(R/R{sub 200}){sup 1.1{+-}0.3} for galaxies with R/R{sub 200} {R {R{sub 200}. The increase in the fraction of SFGs toward larger R/R{sub 200} and the isolation of SFGs with reduced SFRs near the cluster center are consistent with the truncation of star formation by ram-pressure stripping, as is the tendency for more massive SFGs to have higher SFRs. We conclude that stripping is more likely than slower processes to drive the properties of SFGs with R R{sub 200} in clusters. We also find that galaxies near the cluster center are more massive than galaxies farther out in the cluster at {approx}3.5{sigma}, which suggests that dynamical relaxation significantly impacts the distribution of cluster galaxies as the clusters evolve.

Atlee, David W.; Martini, Paul, E-mail: atlee@noao.edu [Department of Astronomy, Ohio State University, 4055 McPherson Laboratory, 140 W. 18th Ave., Columbus, OH 43210 (United States)

2012-12-20T23:59:59.000Z

214

The Selection Function of SZ Cluster Surveys  

E-Print Network (OSTI)

We study the nature of cluster selection in Sunyaev-Zel'dovich (SZ) surveys, focusing on single frequency observations and using Monte Carlo simulations incorporating instrumental effects, primary cosmic microwave background (CMB) anisotropies and extragalactic point sources. Clusters are extracted from simulated maps with an optimal, multi-scale matched filter. We introduce a general definition for the survey selection function that provides a useful link between an observational catalog and theoretical predictions. The selection function defined over the observed quantities of flux and angular size is independent of cluster physics and cosmology, and thus provides a useful characterization of a survey. Selection expressed in terms of cluster mass and redshift, on the other hand, depends on both cosmology and cluster physics. We demonstrate that SZ catalogs are not simply flux limited, and illustrate how incorrect modeling of the selection function leads to biased estimates of cosmological parameters. The fact that SZ catalogs are not flux limited complicates survey ``calibration'' by requiring more detailed information on the relation between cluster observables and cluster mass.

J. -B. Melin; J. G. Bartlett; J. Delabrouille

2004-09-23T23:59:59.000Z

215

The CFHT Open Star Cluster Survey I -- Cluster Selection and Data Reduction  

E-Print Network (OSTI)

We present this paper in conjuction with the following as the first results in the CFHT Open Star Cluster Survey. This survey is a large BVR imaging data set of 19 open star clusters in our Galaxy. This data set was taken with the CFH12K mosaic CCD (42' X 28') and the majority of the clusters were imaged under excellent photometric, sub-arcsecond seeing conditions. The combination of multiple exposures extending to deep (V ~ 25) magnitudes with short (white dwarf stars in these clusters and establish observational constraints on the initial-final mass relationship for these stars and the upper mass limit to white dwarf production. Additionally, we hope to better determine the properties of the clusters, such as age and distance, and also test evolution and dynamical theories by analyzing luminosity and mass functions. In order to more easily incorporate this data in further studies, we have produced a catalogue of positions, magnitudes, colors, and stellarity confidence for all stars in each cluster of the survey. This paper is intended both as a source for the astronomical community to obtain information on the clusters in the survey and as a detailed reference of reduction procedures for further publications of individual clusters. We discuss the methods employed to reduce the data and compute the photometric catalogue. The scientific results for each individual cluster and global results from the study of the entire survey will be presented in further publications (results for the rich old open cluster NGC 6819 immediately follow this paper).

Jasonjot Singh Kalirai; Harvey B. Richer; Gregory G. Fahlman; Jean-Charles Cuillandre; Paolo Ventura; Francesca D'Antona; Emmanuel Bertin; Gianni Marconi; Patrick R. Durrell

2001-04-10T23:59:59.000Z

216

Coronal Abundances in Orion Nebula Cluster Stars  

E-Print Network (OSTI)

Following the Chandra Orion Ultradeep Project (COUP) observation, we have studied the chemical composition of the hot plasma in a sample of 146 X-ray bright pre-main sequence stars in the Orion Nebula Cluster. We report measurements of individual element abundances for a subsample of 86 slightly-absorbed and bright X-ray sources, using low resolution X-ray spectra obtained from the Chandra ACIS instrument. The X-ray emission originates from a plasma with temperatures and elemental abundances very similar to those of active coronae in older stars. A clear pattern of abundances vs. First Ionization Potential (FIP) is evident if solar photospheric abundances are assumed as reference. The results are validated by extensive simulations. The observed abundance distributions are compatible with a single pattern of abundances for all stars, although a weak dependence on flare loop size may be present. The abundance of calcium is the only one which appears to vary substantially between stars, but this quantity is affected by relatively large uncertainties. The ensemble properties of the X-ray bright COUP sources confirm that the iron in the emitting plasma is underabundant with respect to both the solar composition and to the average stellar photospheric values. Comparison of the present plasma abundances with those of the stellar photospheres and those of the gaseous component of the nebula, indicates a good agreement for all the other elements with available measurements, and in particular for the high-FIP elements (Ne, Ar, O, and S) and for the low-FIP element Si. We conclude that there is evidence of a significant chemical fractionation effect only for iron, which appears to be depleted by a factor 1.5--3 with respect to the stellar composition.

A. Maggio; E. Flaccomio; F. Favata; G. Micela; S. Sciortino; E. D. Feigelson; K. V. Getman

2007-03-16T23:59:59.000Z

217

A CHEMICAL ABUNDANCE STUDY OF 10 OPEN CLUSTERS BASED ON WIYN -HYDRA SPECTROSCOPY  

SciTech Connect

We present a detailed chemical abundance study of evolved stars in 10 open clusters based on Hydra multi-object echelle spectra obtained with the WIYN 3.5 m telescope. From an analysis of both equivalent widths and spectrum synthesis, abundances have been determined for the elements Fe, Na, O, Mg, Si, Ca, Ti, Ni, Zr, and for two of the 10 clusters, Al and Cr. To our knowledge, this is the first detailed abundance analysis for clusters NGC 1245, NGC 2194, NGC 2355, and NGC 2425. These 10 clusters were selected for analysis because they span a Galactocentric distance range R{sub gc} {approx} 9-13 kpc, the approximate location of the transition between the inner and outer disks. Combined with cluster samples from our previous work and those of other studies in the literature, we explore abundance trends as a function of cluster R{sub gc}, age, and [Fe/H]. As found previously by us and other studies, the [Fe/H] distribution appears to decrease with increasing R{sub gc} to a distance of {approx}12 kpc and then flattens to a roughly constant value in the outer disk. Cluster average element [X/Fe] ratios appear to be independent of R{sub gc}, although the picture for [O/Fe] is more complicated with a clear trend of [O/Fe] with [Fe/H] and sample incompleteness. Other than oxygen, no other element [X/Fe] exhibits a clear trend with [Fe/H]; likewise, there does not appear to be any strong correlation between abundance and cluster age. We divided clusters into different age bins to explore temporal variations in the radial element distributions. The radial metallicity gradient appears to have flattened slightly as a function of time, as found by other studies. There is also some indication that the transition from the inner disk metallicity gradient to the {approx}constant [Fe/H] distribution of the outer disk occurs at different Galactocentric radii for different age bins. However, interpretation of the time evolution of radial abundance distributions is complicated by the unequal R{sub gc} and [Fe/H] ranges spanned by clusters in different age bins.

Jacobson, Heather R. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48823 (United States); Pilachowski, Catherine A. [Department of Astronomy, Indiana University, Bloomington, IN 47405 (United States); Friel, Eileen D., E-mail: jacob189@msu.edu, E-mail: catyp@astro.indiana.edu, E-mail: edfriel@mac.com [Department of Astronomy, Boston University, Boston, MA 02215 (United States)

2011-08-15T23:59:59.000Z

218

The Ages and Metallicities of Early Type Galaxies in the Fornax Cluster  

E-Print Network (OSTI)

We have measured central line strengths for a complete sample of early type galaxies in the Fornax cluster, comprising 11 elliptical and 11 lenticular galaxies, more luminous than M_B=-17. In contrast to the elliptical galaxies in the sample studied by Gonzalez (and recently revisited by Trager) we find that the Fornax ellipticals follow the locus of galaxies of fixed age in Worthey's models and have metallicities varying from roughly solar to three times solar. The lenticular galaxies however exhibit a substantial spread to younger luminosity weighted ages indicating a more extended star formation history. We present measurements of the more sensitive indices: C4668 and Hgamma_A; these confirm and re-enforce the conclusions that the elliptical galaxies are coeval and that only the lenticular galaxies show symptoms of late star-formation. The inferred difference in the age distribution between lenticular and elliptical galaxies is a robust conclusion as the models generate consistent relative ages using different age and metallicity indicators even though the absolute ages remain uncertain. The young luminosity weighted ages of the S0s in the Fornax cluster are consistent with the recent discovery that the fraction of S0 galaxies in intermediate redshift clusters is a factor of 2-3 lower than found locally and suggests that a fraction of the cluster spiral galaxy population has evolved to quiescence in the 5 Gyr interval from z=0.5 to the present. Two of the faintest lenticular galaxies in our sample have blue continua and strong Balmer-line absorption suggesting starbursts \\la2 Gyrs ago. These may be the low redshift analogues of the starburst or post-starburst galaxies seen in clusters at z=0.3, similar to the Hdelta strong galaxies in the Coma cluster.

Harald Kuntschner; Roger L. Davies

1997-10-16T23:59:59.000Z

219

Sampling Distribution of the Time between Effectively Independent Samples  

Science Conference Proceedings (OSTI)

The sampling distribution of the estimate of the “time between effectively independent samples,” T0, is investigated using Monte-Carlo techniques. It is found to be asymptotically unbiased and normally distributed. Agreement between empirical ...

Daniel Wilks

1987-03-01T23:59:59.000Z

220

Environmental Business Cluster | Open Energy Information  

Open Energy Info (EERE)

Business Cluster Business Cluster Jump to: navigation, search Logo: Environmental Business Cluster Name Environmental Business Cluster Address 2 North First Street, Third Floor Place San Jose, California Zip 95112 Region Bay Area Coordinates 37.3456227°, -121.8847222° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":37.3456227,"lon":-121.8847222,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

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221

Nuclear clusters with Halo Effective Field Theory  

E-Print Network (OSTI)

After a brief discussion of effective field theory applied to nuclear clusters, I present the aspect of Coulomb interactions, with applications to low-energy alpha-alpha and nucleon-alpha scattering.

Higa, Renato

2008-01-01T23:59:59.000Z

222

Nuclear clusters with Halo Effective Field Theory  

E-Print Network (OSTI)

After a brief discussion of effective field theory applied to nuclear clusters, I present the aspect of Coulomb interactions, with applications to low-energy alpha-alpha and nucleon-alpha scattering.

Renato Higa

2008-09-30T23:59:59.000Z

223

Clustering and disjoint principal component analysis  

Science Conference Proceedings (OSTI)

A constrained principal component analysis, which aims at a simultaneous clustering of objects and a partitioning of variables, is proposed. The new methodology allows us to identify components with maximum variance, each one a linear combination of ...

Maurizio Vichi; Gilbert Saporta

2009-06-01T23:59:59.000Z

224

Non-parametric mixture models for clustering  

Science Conference Proceedings (OSTI)

Mixture models have been widely used for data clustering. However, commonly used mixture models are generally of a parametric form (e.g., mixture of Gaussian distributions or GMM), which significantly limits their capacity in fitting diverse multidimensional ...

Pavan Kumar Mallapragada; Rong Jin; Anil Jain

2010-08-01T23:59:59.000Z

225

Cluster magnetic fields from active galactic nuclei  

E-Print Network (OSTI)

Active galactic nuclei (AGN) found at the centers of clusters of galaxies are a possible source for weak cluster-wide magnetic fields. To evaluate this scenario, we present 3D adaptive mesh refinement MHD simulations of a cool-core cluster that include injection of kinetic, thermal, and magnetic energy via an AGN-powered jet. Using the MHD solver in FLASH 2, we compare several sub-resolution approaches that link the estimated accretion rate as measured on the simulation mesh to the accretion rate onto the central black hole and the resulting feedback. We examine the effects of magnetized outflows on the accretion history of the black hole and discuss the ability of these models to magnetize the cluster medium.

Sutter, P M; Yang, H -Y

2009-01-01T23:59:59.000Z

226

Flagship Cluster Hiring Initiative Computational Science  

E-Print Network (OSTI)

Flagship Cluster Hiring Initiative Computational Science: Advancing Research, Society and the Economy Gabrielle Allen (PI) Thomas Sterling (Presenter/co-PI) Department of Computer Science Center for Computation & Technology #12;Computational Science: Advancing Research, Society and the Economy, External

Allen, Gabrielle

227

Cluster-Based Adaptive and Batch Filtering  

Science Conference Proceedings (OSTI)

... on the Web, using both 'traditional' search engine [5] and agent-based techniques [6, 7 ... led us to modify the single set-of- clusters model, creating a ...

228

THE LIFETIME AND POWERS OF FR IIs IN GALAXY CLUSTERS  

Science Conference Proceedings (OSTI)

We have identified and studied a sample of 151 FR IIs found in brightest cluster galaxies (BCGs) in the MaxBCG cluster catalog with data from FIRST and NVSS. We have compared the radio luminosities and projected lengths of these FR IIs to the projected length distribution of a range of mock catalogs generated by an FR II model and estimate the FR II lifetime to be 1.9 Multiplication-Sign 10{sup 8} yr. The uncertainty in the lifetime calculation is a factor of two, primarily due to uncertainties in the intracluster medium (ICM) density and the FR II axial ratio. We furthermore measure the jet power distribution of FR IIs in BCGs and find that it is well described by a log-normal distribution with a median power of 1.1 Multiplication-Sign 10{sup 37} W and a coefficient of variation of 2.2. These jet powers are nearly linearly related to the observed luminosities, and this relation is steeper than many other estimates, although it is dependent on the jet model. We investigate correlations between FR II and cluster properties and find that galaxy luminosity is correlated with jet power. This implies that jet power is also correlated with black hole mass, as the stellar luminosity of a BCG should be a good proxy for its spheroid mass and therefore the black hole mass. Jet power, however, is not correlated with cluster richness, nor is FR II lifetime strongly correlated with any cluster properties. We calculate the enthalpy of the lobes to examine the impact of the FR IIs on the ICM and find that heating due to adiabatic expansion is too small to offset radiative cooling by a factor of at least six. In contrast, the jet power is approximately an order of magnitude larger than required to counteract cooling. We conclude that if feedback from FR IIs offsets cooling of the ICM, then heating must be primarily due to another mechanism associated with FR II expansion.

Antognini, Joe; Bird, Jonathan; Martini, Paul, E-mail: antognini@astronomy.ohio-state.edu, E-mail: bird@astronomy.ohio-state.edu, E-mail: martini@astronomy.ohio-state.edu [Department of Astronomy, Ohio State University, 140 W 18th Avenue, Columbus, OH 43210 (United States)

2012-09-10T23:59:59.000Z

229

STRUCTURE AND DYNAMICS OF THE GLOBULAR CLUSTER PALOMAR 13  

SciTech Connect

We present Keck/DEIMOS spectroscopy and Canada-France-Hawaii Telescope/MegaCam photometry for the Milky Way globular cluster Palomar 13. We triple the number of spectroscopically confirmed members, including many repeat velocity measurements. Palomar 13 is the only known globular cluster with possible evidence for dark matter, based on a Keck/High Resolution Echelle Spectrometer 21 star velocity dispersion of {sigma} = 2.2 {+-} 0.4 km s{sup -1}. We reproduce this measurement, but demonstrate that it is inflated by unresolved binary stars. For our sample of 61 stars, the velocity dispersion is {sigma} = 0.7{sup +0.6}{sub -0.5} km s{sup -1}. Combining our DEIMOS data with literature values, our final velocity dispersion is {sigma} = 0.4{sup +0.4}{sub -0.3} km s{sup -1}. We determine a spectroscopic metallicity of [Fe/H] = -1.6 {+-} 0.1 dex, placing a 1{sigma} upper limit of {sigma}{sub [Fe/H]} {approx} 0.2 dex on any internal metallicity spread. We determine Palomar 13's total luminosity to be M{sub V} = -2.8 {+-} 0.4, making it among the least luminous known globular clusters. The photometric isophotes are regular out to the half-light radius and mildly irregular outside this radius. The outer surface brightness profile slope is shallower than typical globular clusters ({Sigma}{proportional_to}r{sup {eta}}, {eta} = -2.8 {+-} 0.3). Thus at large radius, tidal debris is likely affecting the appearance of Palomar 13. Combining our luminosity with the intrinsic velocity dispersion, we find a dynamical mass of M{sub 1/2} = 1.3{sup +2:7}{sub -1.3} Multiplication-Sign 10{sup 3} M{sub Sun} and a mass-to-light ratio of M/L{sub V} = 2.4{sup +5.0}{sub -2.4} M{sub Sun }/L{sub Sun }. Within our measurement errors, the mass-to-light ratio agrees with the theoretical predictions for a single stellar population. We conclude that, while there is some evidence for tidal stripping at large radius, the dynamical mass of Palomar 13 is consistent with its stellar mass and neither significant dark matter, nor extreme tidal heating, is required to explain the cluster dynamics.

Bradford, J. D. [Department of Physics, Central Connecticut State University, 1615 Stanley Street, New Britain, CT 06050 (United States); Geha, M.; Munoz, R. R.; Santana, F. A. [Astronomy Department, Yale University, New Haven, CT 06520 (United States); Simon, J. D. [The Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Cote, P.; Stetson, P. B. [National Research Council of Canada, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Kirby, E.; Djorgovski, S. G., E-mail: jeremydbradford@gmail.com, E-mail: marla.geha@yale.edu [California Institute of Technology, Department of Astronomy, MS 249-17, Pasadena, CA 91106 (United States)

2011-12-20T23:59:59.000Z

230

Rhenium Complexes and Clusters Supported on c-Al2O3: Effects of Rhenium Oxidation State and Rhenium Cluster Size on Catalytic Activity for n-butane Hydrogenolysis  

SciTech Connect

Supported metals prepared from H{sub 3}Re{sub 3}(CO){sub 12} on {gamma}-Al{sub 2}O{sub 3} were treated under conditions that led to various rhenium structures on the support and were tested as catalysts for n-butane conversion in the presence of H{sub 2} in a flow reactor at 533 K and 1 atm. After use, two samples were characterized by X-ray absorption edge positions of approximately 5.6 eV (relative to rhenium metal), indicating that the rhenium was cationic and essentially in the same average oxidation state in each. But the Re-Re coordination numbers found by extended X-ray absorption fine structure spectroscopy (2.2 and 5.1) show that the clusters in the two samples were significantly different in average nuclearity despite their indistinguishable rhenium oxidation states. Spectra of a third sample after catalysis indicate approximately Re{sub 3} clusters, on average, and an edge position of 4.5 eV. Thus, two samples contained clusters approximated as Re{sub 3} (on the basis of the Re-Re coordination number), on average, with different average rhenium oxidation states. The data allow resolution of the effects of rhenium oxidation state and cluster size, both of which affect the catalytic activity; larger clusters and a greater degree of reduction lead to increased activity.

Lobo Lapidus, R.; Gates, B

2009-01-01T23:59:59.000Z

231

Sampling Characteristics of Satellite Orbits  

Science Conference Proceedings (OSTI)

The irregular space-time sampling of any finite region by an orbiting satellite raises difficult questions as to which frequencies and wavenumbers can be determined and which will alias into others. Conventional sampling theorems must be extended ...

Carl Wunsch

1989-12-01T23:59:59.000Z

232

Flux Measurement with Conditional Sampling  

Science Conference Proceedings (OSTI)

A method is proposed to measure scalar fluxes using conditional sampling. Only the mean concentrations of updraft and downdraft samples, the standard deviation of the vertical velocity, and a coefficient of proportionality, b, need to be known. ...

Joost A. Businger; Steven P. Oncley

1990-04-01T23:59:59.000Z

233

Sampling Errors in Seasonal Forecasting  

Science Conference Proceedings (OSTI)

The limited numbers of start dates and ensemble sizes in seasonal forecasts lead to sampling errors in predictions. Defining the magnitude of these sampling errors would be useful for end users as well as informing decisions on resource ...

Stephen Cusack; Alberto Arribas

2009-03-01T23:59:59.000Z

234

The Young Open Cluster NGC 2129  

E-Print Network (OSTI)

The first CCD UBV(RI) photometric study in the area of the doubtful open cluster NGC 2129 is presented. Photometry of a field offset 15 arcmin northward is also provided, to probe the Galactic disk population toward the cluster. Using star counts, proper motions from the UCAC2 catalog, colour-magnitude and colour-colour diagrams we demonstrate that NGC 2129 is a young open cluster. The cluster radius is 2.5 arcmin, and across this region we find evidence of significant differential reddening, although the reddening law seems to be normal toward its direction. Updated estimates of the cluster fundamental parameters are provided. The mean reddening is found to be E(B-V)=0.80$\\pm$0.08 and the distance modulus is $(m-M)_o$= 11.70$\\pm0.30$. Hence, NGC 2129 is located at 2.2$\\pm$0.2 kpc from the Sun inside the Local spiral arm. The age derived from 37 photometrically selected members is estimated to be approximately 10 million years. These stars are used to provide new estimates of the cluster absolute proper motion components.

Giovanni Carraro; Brian Chaboyer; James Perencevich

2005-10-19T23:59:59.000Z

235

Sampling – Soil - Energy Innovation Portal  

INL has developed a method for sampling soil to determine the presence of extremely fine particles such as asbestos.

236

The Open Cluster Chemical Analysis and Mapping Survey: Local Galactic Metallicity Gradient with APOGEE using SDSS DR10  

E-Print Network (OSTI)

The Open Cluster Chemical Analysis and Mapping (OCCAM) Survey aims to produce a comprehensive, uniform, infrared-based dataset for hundreds of open clusters, and constrain key Galactic dynamical and chemical parameters from this sample. This first contribution from the OCCAM survey presents analysis of 141 members stars in 28 open clusters with high-resolution metallicities derived from a large uniform sample collected as part of the SDSS-III/Apache Point Observatory Galactic Evolution Experiment (APOGEE). This sample includes the first high-resolution metallicity measurements for 22 open clusters. With this largest ever uniformly observed sample of open cluster stars we investigate the Galactic disk gradients of both [M/H] and [alpha/M]. We find basically no gradient across this range in [alpha/M], but [M/H] does show a gradient for R_{GC} < 10 kpc and a significant flattening beyond R_{GC} = 10 kpc. In particular, whereas fitting a single linear trend yields an [M/H] gradient of -0.09 +/- 0.03$ dex/kpc -...

Frinchaboy, Peter M; Jackson, Kelly M; O'Connell, Julia; Meyer, Brianne; Zasowski, Gail; Majewski, Steven R; Chojnowksi, S Drew; Johnson, Jennifer A; Prieto, Carlos Allende; Beers, Timothy C; Bizyaev, Dmitry; Brewington, Howard; Cunha, Katia; Ebelke, Garrett; Perez, Ana Elia Garcia; Hearty, Frederick R; Holtzman, Jon; Kinemuchi, Karen; Malanushenko, Elena; Malanushenko, Viktor; Marchante, Moses; Meszaros, Szabolcs; Muna, Demitri; Nidever, David L; Oravetz, Daniel; Pan, Kaike; Schiavon, Ricardo P; Schneider, Donald P; Shetrone, Matthew; Simmons, Audrey; Snedden, Stephanie; Smith, Verne V; Wilson, John C

2013-01-01T23:59:59.000Z

237

Dynamic data assigning assessment clustering of streaming data  

Science Conference Proceedings (OSTI)

Discovering interesting patterns or substructures in data streams is an important challenge in data mining. Clustering algorithms are very often applied to identify single substructures although they are designed to partition a data set. Another problem ... Keywords: Incremental clustering, Noise clustering, Objective function-based clustering

O. Georgieva; F. Klawonn

2008-09-01T23:59:59.000Z

238

Tarazu: optimizing MapReduce on heterogeneous clusters  

Science Conference Proceedings (OSTI)

Data center-scale clusters are evolving towards heterogeneous hardware for power, cost, differentiated price-performance, and other reasons. MapReduce is a well-known programming model to process large amount of data on data center-scale clusters. Most ... Keywords: MapReduce, cluster scheduling, heterogeneous clusters, load imbalance, shuffle

Faraz Ahmad; Srimat T. Chakradhar; Anand Raghunathan; T. N. Vijaykumar

2012-04-01T23:59:59.000Z

239

On possibilistic clustering with repulsion constraints for imprecise data  

Science Conference Proceedings (OSTI)

In possibilistic clustering objects are assigned to clusters according to the so-called membership degrees taking values in the unit interval. Differently from fuzzy clustering, it is not required that the sum of the membership degrees of an object to ... Keywords: Cluster analysis, Fuzzy data, Possibilistic approach, Repulsion term

Maria Brigida Ferraro, Paolo Giordani

2013-10-01T23:59:59.000Z

240

Clustered-Hybrid Multilayer Perceptron network for pattern recognition application  

Science Conference Proceedings (OSTI)

This paper introduces a modified version of the Hybrid Multilayer Perceptron (HMLP) network to improve the performance of the conventional HMLP network. We adopted the Clustering Algorithm from the Radial Basis Function (RBF) network architecture and ... Keywords: Clustered-Hybrid Multilayer Perceptron network, Clustered-Modified Recursive Prediction Error, Clustering Algorithm, Neural network, Pattern Recognition, Radial Basis Function

Nor Ashidi Mat Isa; Wan Mohd Fahmi Wan Mamat

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Feature-based clustering for electricity use time series data  

Science Conference Proceedings (OSTI)

Time series clustering has been shown effective in providing useful information in various applications. This paper presents an efficient computational method for time series clustering and its application focusing creation of more accurate electricity ... Keywords: electricity distribution, electricity use data, feature extraction, feature-based clustering, load curves, time series clustering

Teemu Räsänen; Mikko Kolehmainen

2009-04-01T23:59:59.000Z

242

Soil Sampling | Open Energy Information  

Open Energy Info (EERE)

Soil Sampling Soil Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Soil Sampling Details Activities (10) Areas (9) Regions (1) NEPA(0) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Field Sampling Parent Exploration Technique: Field Sampling Information Provided by Technique Lithology: Stratigraphic/Structural: Can reveal relatively high permeability zones Hydrological: Thermal: Used to locate active hydrothermal systems Dictionary.png Soil Sampling: Soil sampling is a method that can be used for exploration of geothermal resources that lack obvious surface manifestations. Soils that are above or adjacent to a "hidden" hydrothermal system will have a unique chemistry that can be indicative of a hydrothermal system at depth and a zone of

243

Sample Environment | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Home › Instruments › SNS › Sample Environment Home › Instruments › SNS › Sample Environment Sample Environment The Sample Environment Group provides equipment and support for studying materials under controlled conditions (temperature, pressure, magnetic field, chemical environment, etc.). When you come to SNS to conduct an experiment, our front-line teams are there to support you. Although we currently offer a wide range of capabilities, we realize that these capabilities must continually grow. Therefore, we also have a busy research and development team, and we encourage you to partner with them to develop new equipment and techniques. The Sample Environment Equipment Database allows you to search for information about the sample environment equipment available for HFIR and SNS instruments. It will be available in the near future for SNS sample

244

Rock Sampling | Open Energy Information  

Open Energy Info (EERE)

Rock Sampling Rock Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Rock Sampling Details Activities (13) Areas (13) Regions (1) NEPA(0) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Field Sampling Parent Exploration Technique: Field Sampling Information Provided by Technique Lithology: Rock samples are used to define lithology. Field and lab analyses can be used to measure the chemical and isotopic constituents of rock samples. Stratigraphic/Structural: Provides information about the time and environment which formed a particular geologic unit. Microscopic rock textures can be used to estimate the history of stress and strain, and/or faulting. Hydrological: Isotope geochemistry can reveal fluid circulation of a geothermal system.

245

Algorithms for Gene Clustering Analysis on Genomes  

E-Print Network (OSTI)

The increased availability of data in biological databases provides many opportunities for understanding biological processes through these data. As recent attention has shifted from sequence analysis to higher-level analysis of genes across multiple genomes, there is a need to develop efficient algorithms for these large-scale applications that can help us understand the functions of genes. The overall objective of my research was to develop improved methods which can automatically assign groups of functionally related genes in large-scale data sets by applying new gene clustering algorithms. Proposed gene clustering algorithms that can help us understand gene function and genome evolution include new algorithms for protein family classification, a window-based strategy for gene clustering on chromosomes, and an exhaustive strategy that allows all clusters of small size to be enumerated. I investigate the problems of gene clustering in multiple genomes, and define gene clustering problems using mathematical methodology and solve the problems by developing efficient and effective algorithms. For protein family classification, I developed two supervised classification algorithms that can assign proteins to existing protein families in public databases and, by taking into account similarities between the unclassified proteins, allows for progressive construction of new families from proteins that cannot be assigned. This approach is useful for rapid assignment of protein sequences from genome sequencing projects to protein families. A comparative analysis of the method to other previously developed methods shows that the algorithm has a higher accuracy rate and lower mis-classification rate when compared to algorithms that are based on the use of multiple sequence alignments and hidden Markov models. The proposed algorithm performs well even on families with very few proteins and on families with low sequence similarity. Apart from the analysis of individual sequences, identifying genomic regions that descended from a common ancestor helps us study gene function and genome evolution. In distantly related genomes, clusters of homologous gene pairs serve as evidence used in function prediction, operon detection, etc. Thus, reliable identification of gene clusters is critical to functional annotation and analysis of genes. I developed an efficient gene clustering algorithm that can be applied on hundreds of genomes at the same time. This approach allows for large-scale study of evolutionary relationships of gene clusters and study of operon formation and destruction. By placing a stricter limit on the maximum cluster size, I developed another algorithm that uses a different formulation based on constraining the overall size of a cluster and statistical estimates that allow direct comparisons of clusters of different size. A comparative analysis of proposed algorithms shows that more biological insight can be obtained by analyzing gene clusters across hundreds of genomes, which can help us understand operon occurrences, gene orientations and gene rearrangements.

Yi, Gang Man

2011-05-01T23:59:59.000Z

246

(Electronic structure and reactivities of transition metal clusters)  

DOE Green Energy (OSTI)

The following are reported: theoretical calculations (configuration interaction, relativistic effective core potentials, polyatomics, CASSCF); proposed theoretical studies (clusters of Cu, Ag, Au, Ni, Pt, Pd, Rh, Ir, Os, Ru; transition metal cluster ions; transition metal carbide clusters; bimetallic mixed transition metal clusters); reactivity studies on transition metal clusters (reactivity with H{sub 2}, C{sub 2}H{sub 4}, hydrocarbons; NO and CO chemisorption on surfaces). Computer facilities and codes to be used, are described. 192 refs, 13 figs.

Not Available

1992-01-01T23:59:59.000Z

247

[Electronic structure and reactivities of transition metal clusters  

DOE Green Energy (OSTI)

The following are reported: theoretical calculations (configuration interaction, relativistic effective core potentials, polyatomics, CASSCF); proposed theoretical studies (clusters of Cu, Ag, Au, Ni, Pt, Pd, Rh, Ir, Os, Ru; transition metal cluster ions; transition metal carbide clusters; bimetallic mixed transition metal clusters); reactivity studies on transition metal clusters (reactivity with H{sub 2}, C{sub 2}H{sub 4}, hydrocarbons; NO and CO chemisorption on surfaces). Computer facilities and codes to be used, are described. 192 refs, 13 figs.

Not Available

1992-08-01T23:59:59.000Z

248

THE GLOBULAR CLUSTER SYSTEM OF NGC 4636 AND FORMATION OF GLOBULAR CLUSTERS IN GIANT ELLIPTICAL GALAXIES  

SciTech Connect

We present a spectroscopic analysis of the metallicities, ages, and alpha-elements of the globular clusters (GCs) in the giant elliptical galaxy (gE) NGC 4636 in the Virgo Cluster. Line indices of the GCs are measured from the integrated spectra obtained with Faint Object Camera and Spectrograph on the Subaru 8.2 m Telescope. We derive [Fe/H] values of 59 GCs based on the Brodie and Huchra method, and [Z/H], age, and [{alpha}/Fe] values of 33 GCs from the comparison of the Lick line indices with single stellar population models. The metallicity distribution of NGC 4636 GCs shows a hint of a bimodality with two peaks at [Fe/H] = -1.23({sigma} = 0.32) and -0.35({sigma} = 0.19). The age spread is large from 2 Gyr to 15 Gyr and the fraction of young GCs with age <5 Gyr is about 27%. The [{alpha}/Fe] of the GCs shows a broad distribution with a mean value [{alpha}/Fe] Almost-Equal-To 0.14 dex. The dependence of these chemical properties on the galactocentric radius is weak. We also derive the metallicities, ages, and [{alpha}/Fe] values for the GCs in other nearby gEs (M87, M49, M60, NGC 5128, NGC 1399, and NGC 1407) from the line index data in the literature using the same methods as used for NGC 4636 GCs. The metallicity distribution of GCs in the combined sample of seven gEs including NGC 4636 is found to be bimodal, supported by the KMM test with a significance level of >99.9%. All these gEs harbor some young GCs with ages less than 5 Gyr. The mean age of the metal-rich GCs ([Fe/H] >-0.9) is about 3 Gyr younger than that of the metal-poor GCs. The mean value of [{alpha}/Fe] of the gE GCs is smaller than that of the Milky Way GCs. We discuss these results in the context of GC formation in gEs.

Park, Hong Soo; Lee, Myung Gyoon [Astronomy Program, Department of Physics and Astronomy, Seoul National University (Korea, Republic of); Hwang, Ho Seong [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Kim, Sang Chul [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Arimoto, Nobuo; Yamada, Yoshihiko [National Astronomical Observatory of Japan, Tokyo (Japan); Tamura, Naoyuki [Kavli Institute for Physics and Mathematics of the Universe, University of Tokyo, Kashiwa City 277-8583 (Japan); Onodera, Masato, E-mail: hspark@astro.snu.ac.kr, E-mail: mglee@astro.snu.ac.kr, E-mail: hhwang@cfa.harvard.edu, E-mail: sckim@kasi.re.kr, E-mail: arimoto.n@nao.ac.jp, E-mail: yoshihiko.yamada@nao.ac.jp, E-mail: naoyuki.tamura@ipmu.jp, E-mail: monodera@phys.ethz.ch [Institute for Astronomy, ETH Zuerich, Wolfgang-Pauli-strasse 27, 8093 Zuerich (Switzerland)

2012-11-10T23:59:59.000Z

249

DISENTANGLING THE ROLE OF ENVIRONMENTAL PROCESSES IN GALAXY CLUSTERS  

SciTech Connect

In this work, we present the results of a novel approach devoted to disentangling the role of the environmental processes affecting galaxies in clusters. This is based on the analysis of the near-UV (NUV) - r' distributions of a large sample of star-forming galaxies in clusters spanning more than four absolute magnitudes. The galaxies inhabit three distinct environmental regions: virial regions, cluster infall regions, and field environment. We have applied rigorous statistical tests to analyze both the complete NUV - r' distributions and their averages for three different bins of the r'-band galaxy luminosity down to M{sub r{sup '}}{approx}-18, throughout the three environmental regions considered. We have identified the environmental processes that significantly affect the star-forming galaxies in a given luminosity bin by using criteria based on the characteristics of these processes: their typical timescales, the regions where they operate, and the galaxy luminosity range for which their effects are more intense. We have found that the high-luminosity (M{sub r{sup '}}{<=}-20) star-forming galaxies do not show significant signs in their star formation activity of being affected by: (1) the environment in the last {approx}10{sup 8} yr, or (2) a sudden quenching in the last 1.5 Gyr. The intermediate-luminosity (-20< M{sub r{sup '}}{<=}-19) star-forming galaxies appear to be affected by starvation in the virial regions and by the harassment in the virial and infall regions. Low-luminosity (-19

Hernandez-Fernandez, Jonathan D.; Vilchez, J. M.; Iglesias-Paramo, J., E-mail: jonatan@iaa.es [Instituto de Astrofisica de Andalucia, Glorieta de la Astronomia s/n, 18008 Granada (Spain)

2012-05-20T23:59:59.000Z

250

Size-restricted cluster formation and cluster maintenance technique for mobile ad hoc networks  

Science Conference Proceedings (OSTI)

Mobile ad hoc networks may be composed of a large number of nodes and hence a hierarchical cluster-based structure can be employed to address the scalability issues of the large network. In this paper we propose a size-restricted, distributed clustering ...

Gayathri Venkataraman; Sabu Emmanuel; Srikanthan Thambipillai

2007-03-01T23:59:59.000Z

251

TopCluster: A hybrid cluster model to support dynamic deployment in Grid  

Science Conference Proceedings (OSTI)

Cluster virtualization is a promising approach to construct customized execution environments for Grid users. However, Virtual-Machine Cluster (VCluster) comes with the cost of the overhead caused by virtual machines, which therefore degrades system ... Keywords: Distributed architectures, Distributed systems, Heterogeneous (hybrid) systems

Gang Chen; Yongwei Wu; Jie Wu; Weimin Zheng

2013-03-01T23:59:59.000Z

252

An ACS Survey of Globular Clusters V: Star Catalog for Each Cluster  

E-Print Network (OSTI)

The ACS Survey of Globular Clusters has used HST's Wide-Field Channel to obtain uniform imaging of 65 of the nearest globular clusters to provide an extensive homogeneous dataset for a broad range of scientific investigations. The survey goals required not only a uniform observing strategy, but also a uniform reduction strategy. To this end, we designed a sophisticated software program to process the cluster data in an automated way. The program identifies stars simultaneously in the multiple dithered exposures for each cluster and measures them using the best available PSF models. We describe here in detail the program's rationale, algorithms, and output. The routine was also designed to perform artificial-star tests, and we run a standard set of ~10^5 tests for each cluster in the survey. The catalog described here will be exploited in a number of upcoming papers and will eventually be made available to the public via the world-wide web.

Jay Anderson; Ata Sarajedini; Luigi R. Bedin; Ivan R. King; Giampaolo Piotto; I. Neill Reid; Michael Siegel; Steven R. Majewski; Nathaniel E. Q. Paust; Antonio Aparicio; Antonino P. Milone; Brian Chaboyer; Alfred Rosenberg

2008-04-12T23:59:59.000Z

253

An ACS Survey of Globular Clusters V: Star Catalog for Each Cluster  

E-Print Network (OSTI)

The ACS Survey of Globular Clusters has used HST's Wide-Field Channel to obtain uniform imaging of 65 of the nearest globular clusters to provide an extensive homogeneous dataset for a broad range of scientific investigations. The survey goals required not only a uniform observing strategy, but also a uniform reduction strategy. To this end, we designed a sophisticated software program to process the cluster data in an automated way. The program identifies stars simultaneously in the multiple dithered exposures for each cluster and measures them using the best available PSF models. We describe here in detail the program's rationale, algorithms, and output. The routine was also designed to perform artificial-star tests, and we run a standard set of ~10^5 tests for each cluster in the survey. The catalog described here will be exploited in a number of upcoming papers and will eventually be made available to the public via the world-wide web.

Anderson, Jay; Bedin, Luigi R; King, Ivan R; Piotto, Giampaolo; Reid, I Neill; Siegel, Michael; Majewski, Steven R; Paust, Nathaniel E Q; Aparicio, Antonio; Milone, Antonino P; Chaboyer, Brian; Rosenberg, Alfred

2008-01-01T23:59:59.000Z

254

Fuzzy Logic Connectivity in Semiconductor Defect Clustering  

Science Conference Proceedings (OSTI)

In joining defects on semiconductor wafer maps into clusters, it is common for defects caused by different sources to overlap. Simple morphological image processing tends to either join too many unrelated defects together or not enough together. Expert semiconductor fabrication engineers have demonstrated that they can easily group clusters of defects from a common manufacturing problem source into a single signature. Capturing this thought process is ideally suited for fuzzy logic. A system of rules was developed to join disconnected clusters based on properties such as elongation, orientation, and distance. The clusters are evaluated on a pair-wise basis using the fuzzy rules and are joined or not joined based on a defuzzification and threshold. The system continuously re-evaluates the clusters under consideration as their fuzzy memberships change with each joining action. The fuzzy membership functions for each pair-wise feature, the techniques used to measure the features, and methods for improving the speed of the system are all developed. Examples of the process are shown using real-world semiconductor wafer maps obtained from chip manufacturers. The algorithm is utilized in the Spatial Signature Analyzer (SSA) software, a joint development project between Oak Ridge National Lab (ORNL) and SEMATECH.

Gleason, S.S.; Kamowski, T.P.; Tobin, K.W.

1999-01-24T23:59:59.000Z

255

The Relative Ages of Galactic Globular Clusters  

E-Print Network (OSTI)

We present a review of the present state of knowledge regarding the relative ages of Galactic globular clusters. First, we discuss the relevant galaxy formation models and describe the detailed predictions they make with respect to the formation timescale and chemical evolution of the globular clusters. Next, the techniques used to estimate globular cluster ages are described and evaluated with particular emphasis on the advantages and disadvantages of each method. With these techniques as a foundation, we present arguments in favor of the following assertions: 1) The age of a globular cluster is the likeliest candidate to be the global second parameter, which along with metal abundance, controls the morphology of the horizonal branch. 2) A total age range of as much as $\\sim$5 Gyr exists among the bulk of the Galactic globulars. 3) There is a significant relation between age and metallicity among the Galactic globular clusters if the slope of the \\mvrr-\\feh relation is less than $\\sim$0.23. These conclusions along with other supporting evidence favor a formation scenario in which the inner regions of the Galactic halo collapsed in a monotonic fashion over a short time period much less than 1 Gyr. In contrast, the outer regions of the halo fragmented and collapsed in a chaotic manner over several Gyrs.

Ata Sarajedini; Brian Chaboyer; Pierre Demarque

1997-10-22T23:59:59.000Z

256

Photoionising feedback in star cluster formation  

E-Print Network (OSTI)

We present the first ever hydrodynamic calculations of star cluster formation that incorporate the effect of feedback from ionising radiation. In our simulations, the ionising source forms in the cluster core at the intersection of several dense filaments of inflowing gas. We show that these filaments collimate ionised outflows and suggest such an environmental origin for at least some observed outflows in regions of massive star formation. Our simulations show both positive feedback (i.e. promotion of star formation in neutral gas compressed by expanding HII regions) and negative feedback (i.e. suppression of the accretion flow in to the central regions). We show that the volume filling factor of ionised gas is very different in our simulations than would result from the case where the central source interacted with an azimuthally smoothed gas density distribution. As expected, gas density is the key parameter in determining whether clusters are unbound by photoionising radiation. Nevertheless, we find - on account of the acceleration of a small fraction of the gas to high velocities in the outflows - that the deposition in the gas of an energy that exceeds the binding energy of the cluster is not a sufficient criterion for unbinding the bulk of the cluster mass.

J. E. Dale; I. A. Bonnell; C. J. Clarke; M. R. Bate

2005-01-10T23:59:59.000Z

257

Clustering of Aerosols in Atmospheric Turbulent Flow  

E-Print Network (OSTI)

A mechanism of formation of small-scale inhomogeneities in spatial distributions of aerosols and droplets associated with clustering instability in the atmospheric turbulent flow is discussed. The particle clustering is a consequence of a spontaneous breakdown of their homogeneous space distribution due to the clustering instability, and is caused by a combined effect of the particle inertia and a finite correlation time of the turbulent velocity field. In this paper a theoretical approach proposed in Phys. Rev. E 66, 036302 (2002) is further developed and applied to investigate the mechanisms of formation of small-scale aerosol inhomogeneities in the atmospheric turbulent flow. The theory of the particle clustering instability is extended to the case when the particle Stokes time is larger than the Kolmogorov time scale, but is much smaller than the correlation time at the integral scale of turbulence. We determined the criterion of the clustering instability for the Stokes number larger than 1. We discussed applications of the analyzed effects to the dynamics of aerosols and droplets in the atmospheric turbulent flow.

T. Elperin; N. Kleeorin; M. A. Liberman; V. L'vov; I. Rogachevskii

2007-02-15T23:59:59.000Z

258

Sample page | Open Energy Information  

Open Energy Info (EERE)

Sample page Sample page Jump to: navigation, search This page has been rated 13[1][2] on the scale of awesomness. This page is awesome! The above text is generated by the SampleTemplate. Try editing it and changing the level of awesomeness to see the template react. Hint: It says something different depending on whether or not the page is at least 5 awesome. This page is related to the following topics[3][4]: References Sample pages Help pages Additional Info Name Sample page Awesomeness 13 Topics (raw) References; Sample pages; Help pages; References ↑ Francis C. Monastero. 2002. An overview of industry-military cooperation in the development of power operations at the Coso geothermal field in southern California. GRC Bulletin. . ↑ EPRI. 12/12/2012. Assessment and Mapping of the Riverine

259

Acceptance sampling using judgmental and randomly selected samples  

SciTech Connect

We present a Bayesian model for acceptance sampling where the population consists of two groups, each with different levels of risk of containing unacceptable items. Expert opinion, or judgment, may be required to distinguish between the high and low-risk groups. Hence, high-risk items are likely to be identifed (and sampled) using expert judgment, while the remaining low-risk items are sampled randomly. We focus on the situation where all observed samples must be acceptable. Consequently, the objective of the statistical inference is to quantify the probability that a large percentage of the unsampled items in the population are also acceptable. We demonstrate that traditional (frequentist) acceptance sampling and simpler Bayesian formulations of the problem are essentially special cases of the proposed model. We explore the properties of the model in detail, and discuss the conditions necessary to ensure that required samples sizes are non-decreasing function of the population size. The method is applicable to a variety of acceptance sampling problems, and, in particular, to environmental sampling where the objective is to demonstrate the safety of reoccupying a remediated facility that has been contaminated with a lethal agent.

Sego, Landon H.; Shulman, Stanley A.; Anderson, Kevin K.; Wilson, John E.; Pulsipher, Brent A.; Sieber, W. Karl

2010-09-01T23:59:59.000Z

260

Sample  

Science Conference Proceedings (OSTI)

... deficits by gouging California energy consumers, must ... to state of the art information technology. ... Industry and organization specific knowledge is ...

2010-03-22T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Sample State and Local Ballots  

Science Conference Proceedings (OSTI)

Sample State and Local Ballots. ... We thank the election officials who have contributed to this effort. State, County/Municipality, Ballot, Election, Date, ...

2010-10-05T23:59:59.000Z

262

IWTU Process Sample Analysis Report  

SciTech Connect

CH2M-WG Idaho (CWI) requested that Battelle Energy Alliance (BEA) analyze various samples collected during June – August 2012 at the Integrated Waste Treatment Facility (IWTU). Samples of IWTU process materials were collected from various locations in the process. None of these samples were radioactive. These samples were collected and analyzed to provide more understanding of the compositions of various materials in the process during the time of the process shutdown that occurred on June 16, 2012, while the IWTU was in the process of nonradioactive startup.

Nick Soelberg

2013-04-01T23:59:59.000Z

263

Homeowner Soil Sample Information Form  

E-Print Network (OSTI)

Homeowners should submit this form with their soil samples when requesting a soil test from the Texas A&M Soil Testing Laboratory.

Provin, Tony

2007-04-11T23:59:59.000Z

264

HAP sampling at Tidd PFBC  

SciTech Connect

The objective of this project was to sample process streams of the Tidd PFBC plant and to characterize the HAPs associated with those various process streams. The data are comparable to HAP data collected by DOE and EPRI studies at conventional coal-fired utility plants. Twelve sampling locations throughout Tidd PFBC plant were selected to characterize the HAPs in the plant cycle. Sampling was conducted at the input and output of the combustor, before and after the hot gas clean-up (HGCU) and before and after the electrostatic precipitator (ESP). Seven solid process streams were sampled including coal and sorbent to the PFBC unit and ash from the PFBC bed and ash collection devices. Service water which is mixed with the coal to make coal paste was the only liquid process stream sampled. The four gas stream samples collected were the inlets and outlets of the HGCU and ESP. Lists are presented for field sampling requirements for gas streams; coal sorbent, and service water; and ash samples. Lists of elements and compounds (inorganic, organic, and radioactive) are also included. The samples have been collected and are being analyzed.

Mudd, M.J.; Dal Porto, P.A.

1994-10-01T23:59:59.000Z

265

THE GEMINI/HST CLUSTER PROJECT: STRUCTURAL AND PHOTOMETRIC PROPERTIES OF GALAXIES IN THREE z = 0.28-0.89 CLUSTERS  

SciTech Connect

We present the data processing and analysis techniques we are using to determine the structural and photometric properties of galaxies in our Gemini/HST Galaxy Cluster Project sample. The goal of this study is to understand cluster galaxy evolution in terms of scaling relations and structural properties of cluster galaxies at redshifts 0.15 < z < 1.0. To derive parameters such as total magnitude, half-light radius, effective surface brightness, and Sersic n, we fit r {sup 1/4} law and Sersic function two-dimensional surface brightness profiles to each of the galaxies in our sample. Using simulated galaxies, we test how the assumed profile affects the derived parameters and how the uncertainties affect our Fundamental Plane results. We find that while fitting galaxies that have Sersic index n < 4 with r {sup 1/4} law profiles systematically overestimates the galaxy radius and flux, the combination of profile parameters that enter the Fundamental Plane has uncertainties that are small. Average systematic offsets and associated random uncertainties in magnitude and log r{sub e} for n>2 galaxies fitted with r {sup 1/4} law profiles are -0.1 {+-} 0.3 and 0.1 {+-} 0.2, respectively. The combination of effective radius and surface brightness, log r{sub e} - {beta}log (I) {sub e}, that enters the Fundamental Plane produces offsets smaller than -0.02 {+-} 0.10. This systematic error is insignificant and independent of galaxy magnitude or size. A catalog of photometry and surface brightness profile parameters is presented for three of the clusters in our sample, RX J0142.0+2131, RX J0152.7-1357, and RX J1226.9+3332 at redshifts 0.28, 0.83, and 0.89, respectively.

Chiboucas, Kristin; Joergensen, Inger [Gemini Observatory, 670 N. A'ohoku Pl., Hilo, HI 96720 (United States); Barr, Jordi; Collobert, Maela; Davies, Roger [Department of Astrophysics, University of Oxford, Keble Rd, Oxford OX1 3RH (United Kingdom); Flint, Kathleen [National Postdoctoral Association, 1200 New York Avenue, NW, Suite 635, Washington, DC 20005 (United States)], E-mail: kchibouc@gemini.edu, E-mail: ijorgensen@gemini.edu, E-mail: jordi.barr@nottingham.ac.uk, E-mail: maela.collobert@gmail.com, E-mail: rld@astro.ox.ac.uk, E-mail: kflint@nationalpostdoc.org

2009-10-01T23:59:59.000Z

266

THE FORMATION OF YOUNG DENSE STAR CLUSTERS THROUGH MERGERS  

SciTech Connect

Young star clusters such as NGC 3603 and Westerlund 1 and 2 in the Milky Way and R136 in the Large Magellanic Cloud are dynamically more evolved than expected based on their current relaxation times. In particular, the combination of a high degree of mass segregation, a relatively low central density, and the large number of massive runaway stars in their vicinity are hard to explain with the monolithic formation of these clusters. Young star clusters can achieve such a mature dynamical state if they formed through the mergers of a number of less massive clusters. The shorter relaxation times of less massive clusters cause them to dynamically evolve further by the time they merge, and the merger product preserves the memory of the dynamical evolution of its constituent clusters. With a series of N-body simulations, we study the dynamical evolution of single massive clusters and those that are assembled through merging smaller clusters together. We find that the formation of massive star clusters through the mergers of smaller clusters can reproduce the currently observed spatial distribution of massive stars, the density, and the characteristics (number and mass distribution) of the stars ejected as runaways from young dense clusters. We therefore conclude that these clusters and possibly other young massive star clusters formed through the mergers of smaller clusters.

Fujii, M. S.; Portegies Zwart, S. F. [Leiden Observatory, Leiden University, NL-2300RA Leiden (Netherlands); Saitoh, T. R. [Interactive Research Center of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8551 (Japan)

2012-07-01T23:59:59.000Z

267

Supersonic Bare Metal Cluster Beams. Final Report  

DOE R&D Accomplishments (OSTI)

A major portion of the project involved elucidating the relation between reactivity and the electronic structure of transition-metal (TM) clusters of 2--200 atoms, which required the construction and continuous development of two principal apparati; the Fourier Transform-Ion Cyclotron Resonance (FT-ICR) apparatus, and Ultraviolet Photoelectron Spectroscopy (UPS). Together, these machines have enabled the most detailed probing of the structure and chemical reactivity of TM clusters. Clusters of all the transition metals were included in these studies. Fundamental aspects in chemisorption, reactivity, and heterogeneous catalysis have also become better understood as a result of these experiments for important classes of systems such as H{sub 2}, CO, and CO{sub 2} adsorbed onto clusters of many of the metals listed above. In particular, a correlation was found between reactivity of H{sub 2} with Fe, Co, and Ni clusters and differences between the cluster IP and EA. As recounted in a previous technical report, the DOE`s role in the initial discovery of fullerenes at Rice was central, and from the start investigations were made into metal atoms trapped in the fullerenes cage. More recently, the authors have discovered that 2--4 atoms of La, Y, or Sc can be produced by laser vaporization of composite graphite/metal-oxide disks. This work was largely motivated by the prospects of using such endohedral TM metals for their catalytic activity without the well-known difficulties of effective support media and lack of control over particle size. Thus, while it will certainly be important to discover ways to efficiently scale up production (e.g., the solar generation method explored with DOE support), the efforts have concentrated more on characterization, purification, and manipulation of doped fullerenes. For the past two years, much of the group`s effort has involved the production, purification, and characterization of carbon nanotubes.

Smalley, R. E.

1997-10-14T23:59:59.000Z

268

The large scale clustering of radio sources  

E-Print Network (OSTI)

The observed two-point angular correlation function, w(theta), of mJy radio sources exhibits the puzzling feature of a power-law behaviour up to very large (almost 10 degrees) angular scales which cannot be accounted for in the standard hierarchical clustering scenario for any realistic redshift distribution of such sources. After having discarded the possibility that the signal can be explained by a high density local source population, we find no alternatives to assuming that - at variance with all the other extragalactic populations studied so far, and in particular with optically selected quasars - radio sources responsible for the large-scale clustering signal were increasingly less clustered with increasing look-back time, up to at least z=1. The data are accurately accounted for in terms of a bias function which decreases with increasing redshift, mirroring the evolution with cosmic time of the characteristic halo mass, M_{star}, entering the non linear regime. In the framework of the `concordance cosmology', the effective halo mass controlling the bias parameter is found to decrease from about 10^{15} M_{sun}/h at z=0 to the value appropriate for optically selected quasars, 10^{13} M_{sun}/h, at z=1.5. This suggests that, in the redshift range probed by the data, the clustering evolution of radio sources is ruled by the growth of large-scale structure, and that they are associated with the densest environments virializing at any cosmic epoch. The data provide only loose constraints on radio source clustering at z>1 so we cannot rule out the possibility that at these redshifts the clustering evolution of radio sources enters a different regime, perhaps similar to that found for optically selected quasars. The dependence of w(theta) on cosmological parameters is also discussed.

M. Negrello; M. Magliocchetti; G. De Zotti

2006-02-13T23:59:59.000Z

269

Automatic induction of verb classes using clustering  

E-Print Network (OSTI)

and Shi, 2001) which consistently outperforms other previous methods in our studies. We also introduce a method to automatically de- tect the number of clusters for SPEC (Zelnik-Manor and Perona, 2004). In addition, we introduce HGFC (Yu et al., 2006) as a... and Shi, 2001) which consistently outperforms other previous methods in our studies. We also introduce a method to automatically de- tect the number of clusters for SPEC (Zelnik-Manor and Perona, 2004). In addition, we introduce HGFC (Yu et al., 2006) as a...

Sun, Lin

2013-04-30T23:59:59.000Z

270

Photocatalytic semiconductor clusters for fuel production  

DOE Green Energy (OSTI)

High quality crystalline, monodisperse nanometer-size semiconductor clusters were successfully grown using an inverse micellar synthesis process and their optical and structural properties were studied. Among the materials studied were PbS, FeS{sub 2}, MoS{sub 2}, CdS and related compounds. The results demonstrated strong electronic quantum confinement effects and broad tailorability of the bandgaps with decreasing cluster size, features that are important for the potential use of these materials as photocatalysts for solar fuel production and solar detoxification. The highlights of the work are included in an Executive Summary.

Wilcoxon, J.P.; Bliss, D.E.; Martin, J.E. [and others

1995-10-01T23:59:59.000Z

271

Coupled-cluster computations of atomic nuclei  

E-Print Network (OSTI)

In the past decade, coupled-cluster theory has seen a renaissance in nuclear physics, with computations of neutron-rich and medium-mass nuclei. The method is efficient for nuclei with product-state references, and it describes many aspects of weakly bound and unbound nuclei. This report reviews the technical and conceptual developments of this method in nuclear physics, and the results of coupled-cluster calculations for nucleonic matter, and for exotic isotopes of helium, oxygen, calcium, and some of their neighbors.

G. Hagen; T. Papenbrock; M. Hjorth-Jensen; D. J. Dean

2013-12-30T23:59:59.000Z

272

Forecasting constraints on the cosmic duality relation with galaxy clusters  

E-Print Network (OSTI)

One of the fundamental hypotheses in observational cosmology is the validity of the so-called cosmic distance-duality relation (CDDR). In this paper, we perform Monte Carlo simulations based on the method developed in Holanda, Goncalves & Alcaniz (2012) [JCAP 1206 (2012) 022] to answer the following question: what is the number of galaxy clusters observations N_{crit} needed to check the validity of this relation at a given confidence level? At 2\\sigma, we find that N_{crit} should be increased at least by a factor of 5 relative to the current sample size if we assume the current observational uncertainty \\sigma_{obs}. Reducing this latter quantity by a factor of 2, we show that the present number of data would be already enough to check the validity of the CDDR at 2\\sigma.

R. S. Goncalves; J. S. Alcaniz; J. C. Carvalho; R. F. L. Holanda

2013-06-27T23:59:59.000Z

273

A review on particle swarm optimization algorithms and their applications to data clustering  

Science Conference Proceedings (OSTI)

Data clustering is one of the most popular techniques in data mining. It is a method of grouping data into clusters, in which each cluster must have data of great similarity and high dissimilarity with other cluster data. The most popular clustering ... Keywords: Data clustering, Data mining, K-mean clustering, Particle swarm optimization

Sandeep Rana; Sanjay Jasola; Rajesh Kumar

2011-03-01T23:59:59.000Z

274

Field Sampling | Open Energy Information  

Open Energy Info (EERE)

form form View source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit with form History Facebook icon Twitter icon » Field Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Field Sampling Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Field Sampling Parent Exploration Technique: Field Techniques Information Provided by Technique Lithology: Rock samples are used to define lithology. Field and lab analyses can be used to measure the chemical and isotopic constituents of rock samples. Stratigraphic/Structural: Can reveal relatively high permeability zones. Provides information about the time and environment which formed a particular geologic unit. Microscopic rock textures can be used to estimate the history of stress and strain, and/or faulting.

275

Spectroscopy at metal cluster surfaces. Annual report, Year 2  

Science Conference Proceedings (OSTI)

The focus of our research program is the study of gas phase metal clusters to evaluate their potential to model fundamental interactions present on metal surfaces. To do this, we characterize the chemical bonding present between the component atoms in metal clusters as well as the bonding exhibited by ``physisorption`` on cluster surfaces. Electronic spectra, vibrational frequencies and bond neutral and ionized clusters with a variety of laser/mass spectrometry techniques. We are particularly interested in bimetallic cluster systems, and how their properties compare to those of corresponding pure metal clusters.

Duncan, M.A.

1995-08-01T23:59:59.000Z

276

The Use of Edge-Betweenness Clustering to Investigate Biological Function in Protein Interaction Networks  

E-Print Network (OSTI)

homeostasis 1/15 Cluster: 4 GO:46916 IDs: NM_000146 Cluster: 4 GO:8104 protein localization 1/15 Cluster: 4 GO:8104 IDs: NM_016224 Cluster: 4 GO:9451 RNA modification 1/15 Cluster: 4 GO:9451 IDs: NM_002582 Cluster: 4 GO:30005 di-, tri-valent inorganic cation... homeostasis 1/15 Cluster: 4 GO:30005 IDs: NM_000146 Cluster: 4 GO:6916 anti-apoptosis 1/15 Cluster: 4 GO:6916 IDs: NM_012138 Cluster: 4 GO:30705 cytoskeleton-dependent intracellular transport 1/15 Cluster: 4 GO:30705 IDs: NM_014183 Cluster: 4 GO:7292 female...

Dunn, Ruth; Dudbridge, Frank; Sanderson, Christopher M

2005-03-01T23:59:59.000Z

277

Network regression with predictive clustering trees  

Science Conference Proceedings (OSTI)

Network data describe entities represented by nodes, which may be connected with (related to) each other by edges. Many network datasets are characterized by a form of autocorrelation, where the value of a variable at a given node depends on the values ... Keywords: Autocorrelation, Network data, Predictive clustering trees, Regression inference

Daniela Stojanova; Michelangelo Ceci; Annalisa Appice; Sašo DžEroski

2012-09-01T23:59:59.000Z

278

Clustering local frequency items in multiple databases  

Science Conference Proceedings (OSTI)

Frequent items could be considered as a basic type of patterns in a database. In the context of multiple data sources, most of the global patterns are based on local frequency items. A multi-branch company transacting from different branches often needs ... Keywords: Association, Clustering, Data mining, Measure of association, Multi-database mining

Animesh Adhikari

2013-07-01T23:59:59.000Z

279

Cluster ensembles in collaborative filtering recommendation  

Science Conference Proceedings (OSTI)

Recommender systems, which recommend items of information that are likely to be of interest to the users, and filter out less favored data items, have been developed. Collaborative filtering is a widely used recommendation technique. It is based on the ... Keywords: Cluster ensembles, Collaborative filtering, Recommender systems, Self-organizing maps, k-Means

Chih-Fong Tsai; Chihli Hung

2012-04-01T23:59:59.000Z

280

Graph clustering with network structure indices  

Science Conference Proceedings (OSTI)

Graph clustering has become ubiquitous in the study of relational data sets. We examine two simple algorithms: a new graphical adaptation of the k-medoids algorithm and the Girvan-Newman method based on edge betweenness centrality. We show that ...

Matthew J. Rattigan; Marc Maier; David Jensen

2007-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

A Cluster Refinement Algorithm for Motif Discovery  

Science Conference Proceedings (OSTI)

Finding Transcription Factor Binding Sites, i.e., motif discovery, is crucial for understanding the gene regulatory relationship. Motifs are weakly conserved and motif discovery is an NP-hard problem. We propose a new approach called Cluster Refinement ... Keywords: Transcription factor binding site, motif discovery.

Gang Li; Tak-Ming Chan; Kwong-Sak Leung; Kin-Hong Lee

2010-10-01T23:59:59.000Z

282

Bipartite graph partitioning and data clustering  

Science Conference Proceedings (OSTI)

Many data types arising from data mining applications can be modeled as bipartite graphs, examples include terms and documents in a text corpus, customers and purchasing items in market basket analysis and reviewers and movies in a movie recommender ... Keywords: bipartite graph, correspondence analysis, document clustering, graph partitioning, singular value decomposition, spectral relaxation

Hongyuan Zha; Xiaofeng He; Chris Ding; Horst Simon; Ming Gu

2001-10-01T23:59:59.000Z

283

Solar-like oscillations in cluster stars  

E-Print Network (OSTI)

We present a brief overview of the history of attempts to obtain a clear detection of solar-like oscillations in cluster stars, and discuss the results on the first clear detection, which was made by the Kepler Asteroseismic Science Consortium (KASC) Working Group 2.

Stello, D; Bedding, T R; Brogaard, K; Bruntt, H; Chaplin, W J; Christensen-Dalsgaard, J; Demarque, P; Elsworth, Y P; García, R A; Gilliland, R L; Hekker, S; Huber, D; Karoff, C; Kjeldsen, H; Lebreton, Y; Mathur, S; Meibom, S; Zakowicz, J Molenda-\\; Noels, A; Roxburgh, I W; Aguirre, V S; Sterken, C; Szabó, R

2010-01-01T23:59:59.000Z

284

College of Engineering High Performance Computing Cluster  

E-Print Network (OSTI)

College of Engineering High Performance Computing Cluster Policy and Procedures COE-HPC-01 and registered as requiring high performance computing; the course identification/registrations process the College High Performance Computing system will need register for system access by visiting http

Demirel, Melik C.

285

A Clustering-Driven LDAP Framework  

Science Conference Proceedings (OSTI)

LDAP directories have proliferated as the appropriate storage framework for various and heterogeneous data sources, operating under a wide range of applications and services. Due to the increased amount and heterogeneity of the LDAP data, there is a ... Keywords: DIT organization, LDAP services, clustering, merging criteria, query and retrieval engine

Vassiliki Koutsonikola; Athena Vakali

2011-07-01T23:59:59.000Z

286

MARLA: MapReduce for Heterogeneous Clusters  

Science Conference Proceedings (OSTI)

MapReduce has gradually become the framework of choice for "big data". The MapReduce model allows for efficient and swift processing of large scale data with a cluster of compute nodes. However, the efficiency here comes at a price. The performance of ... Keywords: MapReduce, MARLA, MARIANE, HADOOP

Zacharia Fadika; Elif Dede; Jessica Hartog; Madhusudhan Govindaraju

2012-05-01T23:59:59.000Z

287

Performance implications of virtualizing multicore cluster machines  

Science Conference Proceedings (OSTI)

High performance computers are typified by cluster machines constructed from multicore nodes and using high performance interconnects like Infiniband. Virtualizing such 'capacity computing' platforms implies the shared use of not only the nodes and node ... Keywords: Infiniband, high-performance computing, virtualization

Adit Ranadive; Mukil Kesavan; Ada Gavrilovska; Karsten Schwan

2008-03-01T23:59:59.000Z

288

Hierarchical clustering in improving microblog stream summarization  

Science Conference Proceedings (OSTI)

Microblogging has shown a massive increase in use over the past couple of years. According to recent statistics, Twitter (the most popular microblogging platform) has over 500 million posts per day. In order to help users manage this information overload ... Keywords: event detection, microblog, summarization, text clustering

Andrei Olariu

2013-03-01T23:59:59.000Z

289

Gas sampling in the DST  

SciTech Connect

Characterization of the rock-fluid interactions in the DST will play an important role in understanding the performance of waste package materials and radionuclide transport through the altered zone of a repository. Consequently, the chemistry of fluids and gases originating in the pore space of the rock and the changing compositions observed with time and temperature will be targeted for study in the chemistry boreholes of the DST. The chemical holes have been lined with SEAMIST (Science Engineering Associate Membrane In situ Sampling Technology) liners that allow gas and fluid from the pore spaces of the rock walls to be sampled on-site periodically. The concentrations of certain chemical species in the gases and fluids sampled at those locations will then be analyzed back in the laboratory. The baseline sampling of the rock-pore gases (prior to heater turn- on) is described.

DeLoach, L.; Chairappa, M.; Martinelli, R.; Glassley, B.

1998-01-12T23:59:59.000Z

290

Microfluidic Sample Preparation for Immunoassays  

SciTech Connect

Researchers at Lawrence Livermore National Laboratory are developing means to collect and identify fluid-based biological pathogens in the forms of proteins, viruses, and bacteria. to support detection instruments, they are developing a flexible fluidic sample preparation unit. The overall goal of this Microfluidic Module is to input a fluid sample, containing background particulates and potentially target compounds, and deliver a processed sample for detection. They are developing techniques for sample purification, mixing, and filtration that would be useful to many applications including immunologic and nucleic acid assays. Many of these fluidic functions are accomplished with acoustic radiation pressure or dielectrophoresis. They are integrating these technologies into packaged systems with pumps and valves to control fluid flow through the fluidic circuit.

Visuri, S; Benett, W; Bettencourt, K; Chang, J; Fisher, K; Hamilton, J; Krulevitch, P; Park, C; Stockton, C; Tarte, L; Wang, A; Wilson, T

2001-08-09T23:59:59.000Z

291

Powering The Intra-cluster Filaments in Cool-Core Clusters of Galaxies  

E-Print Network (OSTI)

The first radio surveys of the sky discovered that some large clusters of galaxies contained powerful sources of synchrotron emission. Optical images showed that long linear filaments with bizarre emission-line spectra permeated the intra-cluster medium. Recent observations in the infrared and radio show that these filaments have very strong emission lines of molecular hydrogen and carbon monoxide. The mass of molecular material is quite large, the gas is quite warm, and the filaments have not formed stars despite their ~Gyr age. I will discuss the general astrophysical context of large clusters of galaxies and how large masses of molecular gas can be heated to produce what we observe. The unique properties of the filaments are a result of the unique environment. Magnetically confined molecular filaments are surrounded by the hot intra-cluster medium. Thermal particles with keV energies enter atomic and molecular regions and produce a shower of secondary nonthermal electrons. These secondaries collisionally h...

Ferland, Gary J

2011-01-01T23:59:59.000Z

292

BWR Fuel Deposit Sample Evaluation  

Science Conference Proceedings (OSTI)

River Bend Nuclear Power Station, a boiling water reactor (BWR) plant, experienced fuel defects during Cycle 11. The failed fuel pins were identified during the subsequent refueling outage. To assist analysis of the fuel failure root cause, crud flake deposit samples were collected for analyses. Results on the morphology and distribution of chemical elements in four tenacious crud flakes that are associated with the fuel failures are reported in EPRI report 1009733, BWR Fuel Deposit Sample Evaluation–Riv...

2005-11-29T23:59:59.000Z

293

CCD photometric and mass function study of 9 young Large Magellanic Cloud star clusters  

E-Print Network (OSTI)

We present CCD photometric and mass function study of 9 young Large Magellanic Cloud star clusters namely NGC 1767, NGC 1994, NGC 2002, NGC 2003, NGC 2006, SL 538, NGC 2011, NGC 2098 and NGC 2136. The BVRI data reaching down to V ~ 21 mag, are collected from 3.5-meter NTT/EFOSC2 in sub-arcsec seeing conditions. For NGC 1767, NGC 1994, NGC 2002, NGC 2003, NGC 2011 and NGC 2136, broad band photometric CCD data are presented for the first time. Seven of the 9 clusters have ages between 16 to 25 Myr while remaining two clusters have ages $32\\pm4$ Myr (NGC 2098) and $90\\pm10$ Myr (NGC 2136). For 7 younger clusters, the age estimates based on a recent model and the integrated spectra are found to be systematically lower ($\\sim$ 10 Myr) from the present estimate. In the mass range of $\\sim 2 - 12$ $M_{\\odot}$, the MF slopes for 8 out of nine clusters were found to be similar with the value of $\\gamma$ ranging from $-1.90\\pm0.16$ to $-2.28\\pm0.21$. For NGC 1767 it is flatter with $\\gamma = -1.23\\pm0.27$. Mass segregation effects are observed for NGC 2002, NGC 2006, NGC 2136 and NGC 2098. This is consistent with the findings of Kontizas et al. for NGC 2098. Presence of mass segregation in these clusters could be an imprint of star formation process as their ages are significantly smaller than their dynamical evolution time. Mean MF slope of $\\gamma = -2.22\\pm0.16$ derived for a sample of 25 young ($\\le 100$ Myr) dynamically unevolved LMC stellar systems provide support for the universality of IMF in the intermediate mass range $\\sim 2-12 M_{\\odot}$.

B. Kumar; R. Sagar; J. Melnick

2008-01-07T23:59:59.000Z

294

The chemical abundance of the very metal rich old Open Clusters NGC 6253 and NGC 6791  

E-Print Network (OSTI)

In the framework of a project aiming at deriving in a homogeneous way the properties (age, distance, reddening and detailed chemical abundances) of a large sample of old open clusters, we present here the metal abundance and the abundance ratios of light (C, N, O, Na, Mg, Al, Si, Ca, Ti) and heavier (Cr, Mn, Ni, Ba, Eu) elements in the galactic open clusters NGC 6253 and NGC 6791. We performed spectrum synthesis of selected lines on high resolution spectra of four red clump stars in NGC 6253, taken with the UVES and FEROS spectrographs. We also determined abundances of the same elements for four red clump stars in NGC 6791, observed with SARG, for which we had derived the atmospheric parameters and the iron, carbon and oxygen abundances in a previous paper (Gratton et al. 2006). The average metallicity of NGC 6253 is [Fe/H]=+0.46 (rms = 0.03 dex, systematic error = 0.08 dex), obtained by extensive spectral synthesis of Fe lines. This intermediate age cluster closely resembles the old open cluster NGC 6791, as far as the chemical composition is concerned. C, N, O do not show any significant abundance scatter; they are underabundant with respect to the solar values both in NGC 6253 and NGC 6791. We also find no evident star-to-star scatter in any of the elements measured in both clusters, with the possible exception of Na in NGC 6791. The two clusters show very similar abundances, except for Mg, overabundant in NGC 6791 and not in NGC 6253. Both have solar scaled alpha-elements abundances. We have compared our abundance ratios with literature values for disk giants and dwarfs and bulge giants, finding a general good agreement with the run of elemental ratios with [Fe/H] of disk objects.

Eugenio Carretta; Angela Bragaglia; Raffaele Gratton

2007-06-19T23:59:59.000Z

295

Argonne CNM News: Charge Separation in Silver Clusters  

NLE Websites -- All DOE Office Websites (Extended Search)

Charge Separation in Silver Clusters Charge Separation in Silver Clusters silver clusters Artist's rendering of silver clusters capped with organic ligand molecules. transient kinetics of silver clusters Transient kinetics showing charge recombination in ligand-stabilized silver clusters for different surrounding solvents (water-methanol mixture, acetone, and dichloromethane). Both charge separation and recombination events are faster in more polar solvents. Center for Nanoscale Materials (CNM) users from the Ecole Polytechnique Federale de Lausanne in Switzerland, working with the CNM Nanophotonics Group, have demonstrated the existence of long-lived charge-separated states in silver clusters. The clusters, synthesized chemically in solution, consist of exactly 44 silver atoms and are stabilized by exactly

296

Implementation of a cluster based routing protocol for mobile networks  

Science Conference Proceedings (OSTI)

We show the implementation and the simulation results of a hierarchical, cluster based routing protocol for mobile ad hoc networks using Parallel Virtual Machine (PVM). The network represented by a graph is partitioned into clusters by a graph ...

Geoffrey Marshall; Kayhan Erciyes

2005-05-01T23:59:59.000Z

297

Chapter generation for digital video recorder based on perceptual clustering  

Science Conference Proceedings (OSTI)

We propose a novel automatic chapter generating technique for digital video recorder (DVR) based on a perceptual clustering. Clustering with two-staged hierarchy is introduced for the first time, showing better performance than previous approaches without ...

M. Yamauchi; M. Kimura; J. Ohmiya; J. Nishikawa; I. Okabayashi

2006-09-01T23:59:59.000Z

298

Measuring Clustering in Clouds Using Non-Rayleigh Signal Statistics  

Science Conference Proceedings (OSTI)

The clustering or clumping of droplets appears to be nearly ubiquitous in clouds. Clustering likely plays roles in a number of different physical processes, from the growth of hail, to snow aggregation, to the growth of raindrops, to cloud ...

A. R. Jameson

2005-04-01T23:59:59.000Z

299

Weak lensing flexion as a probe of galaxy cluster substructure  

E-Print Network (OSTI)

Measuring galaxy cluster total masses and the amount of dark matter substructure within galaxy cluster haloes is a fundamental probe of the ACDM model of structure formation, as well as the interactions between baryonic ...

Cain, Benjamin Martin

2011-01-01T23:59:59.000Z

300

Cloud Clusters and Superclusters over the Oceanic Warm Pool  

Science Conference Proceedings (OSTI)

Infrared satellite images of the oceanic warm-pool region (8O°E-160°W) have been objectively processed to reveal tropical “cloud clusters” with temperature colder than a given threshold. Cloud clusters span a somewhat lognormal distribution of ...

Brain E. Mapes; Robert A. Houze Jr.

1993-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

A new clustering approach and its application to BBL placement  

Science Conference Proceedings (OSTI)

A new approach for clustering applied to Building Block placement is presented. Unlike traditional approaches, which only consider local factors such as connectivity and shape matching of blocks in a cluster, our approach (called the GAC method) not ...

M. Y. Yu; X. L. Hong; Y. E. Lien; Z. Z. Ma; J. G. Bo; W. J. Zhuang

1990-03-01T23:59:59.000Z

302

Distributional word clusters vs. words for text categorization  

Science Conference Proceedings (OSTI)

We study an approach to text categorization that combines distributional clustering of words and a Support Vector Machine (SVM) classifier. This word-cluster representation is computed using the recently introduced Information Bottleneck method, ...

Ron Bekkerman; Ran El-Yaniv; Naftali Tishby; Yoad Winter

2003-03-01T23:59:59.000Z

303

Duplex sampling apparatus and method  

DOE Patents (OSTI)

An improved apparatus is provided for sampling a gaseous mixture and for measuring mixture components. The apparatus includes two sampling containers connected in series serving as a independently determine the amounts of condensable and noncondensable gases in admixture from a single sample. More specifically, a first container includes a first port capable of selectively connecting to and disconnecting from a sample source and a second port capable of selectively connecting to and disconnecting from a second container. A second container also includes a first port capable of selectively connecting to and disconnecting from the second port of the first container and a second port capable of either selectively connecting to and disconnecting from a differential pressure source. By cooling a mixture sample in the first container, the condensable vapors form a liquid, leaving noncondensable gases either as free gases or dissolved In the liquid. The condensed liquid is heated to drive out dissolved noncondensable gases, and all the noncondensable gases are transferred to the second container. Then the first and second containers are separated from one another in order to separately determine the amount of noncondensable gases and the amount of condensable gases in the sample.

Brown, P.E.; Lloyd, R.

1991-01-30T23:59:59.000Z

304

Improved sample size determination for attributes and variables sampling  

Science Conference Proceedings (OSTI)

Earlier INMM papers have addressed the attributes/variables problem and, under conservative/limiting approximations, have reported analytical solutions for the attributes and variables sample sizes. Through computer simulation of this problem, we have calculated attributes and variables sample sizes as a function of falsification, measurement uncertainties, and required detection probability without using approximations. Using realistic assumptions for uncertainty parameters of measurement, the simulation results support the conclusions: (1) previously used conservative approximations can be expensive because they lead to larger sample sizes than needed; and (2) the optimal verification strategy, as well as the falsification strategy, are highly dependent on the underlying uncertainty parameters of the measurement instruments. 1 ref., 3 figs.

Stirpe, D.; Picard, R.R.

1985-01-01T23:59:59.000Z

305

COMPARISON OF CONVECTIVE OVERSHOOTING MODELS AND THEIR IMPACT ON ABUNDANCES FROM INTEGRATED LIGHT SPECTROSCOPY OF YOUNG (<3 Gyr) STAR CLUSTERS  

Science Conference Proceedings (OSTI)

As part of an ongoing program to measure detailed chemical abundances in nearby galaxies, we use a sample of young- to intermediate-age clusters in the Large Magellanic Cloud with ages of 10 Myr-2 Gyr to evaluate the effect of isochrone parameters, specifically core convective overshooting, on Fe abundance results from high-resolution, integrated light spectroscopy. In this work we also obtain fiducial Fe abundances from high-resolution spectroscopy of the cluster individual member stars. We compare the Fe abundance results for the individual stars to the results from isochrones and integrated light spectroscopy to determine whether isochrones with convective overshooting should be used in our integrated light analysis of young- to intermediate-age (10 Myr-3 Gyr) star clusters. We find that when using the isochrones from the Teramo group, we obtain more accurate results for young- and intermediate-age clusters over the entire age range when using isochrones without convective overshooting. While convective overshooting is not the only uncertain aspect of stellar evolution, it is one of the most readily parameterized ingredients in stellar evolution models, and thus important to evaluate for the specific models used in our integrated light analysis. This work demonstrates that our method for integrated light spectroscopy of star clusters can provide unique tests for future constraints on stellar evolution models of young- and intermediate-age clusters.

Colucci, Janet E.; Bernstein, Rebecca A., E-mail: jcolucci@ucolick.org, E-mail: rab@ucolick.org [Department of Astronomy and Astrophysics, 1156 High Street, UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States)

2012-04-20T23:59:59.000Z

306

SPITZER OBSERVATIONS OF THE {lambda} ORIONIS CLUSTER. II. DISKS AROUND SOLAR-TYPE AND LOW-MASS STARS  

Science Conference Proceedings (OSTI)

We present IRAC/MIPS Spitzer Space Telescope observations of the solar-type and the low-mass stellar population of the young ({approx}5 Myr) {lambda} Orionis cluster. Combining optical and Two Micron All Sky Survey photometry, we identify 436 stars as probable members of the cluster. Given the distance (450 pc) and the age of the cluster, our sample ranges in mass from 2 M{sub sun} to objects below the substellar limit. With the addition of the Spitzer mid-infrared data, we have identified 49 stars bearing disks in the stellar cluster. Using spectral energy distribution slopes, we place objects in several classes: non-excess stars (diskless), stars with optically thick disks, stars with 'evolved disks' (with smaller excesses than optically thick disk systems), and 'transitional disk' candidates (in which the inner disk is partially or fully cleared). The disk fraction depends on the stellar mass, ranging from {approx}6% for K-type stars (R{sub C} - J 4). We confirm the dependence of disk fraction on stellar mass in this age range found in other studies. Regarding clustering levels, the overall fraction of disks in the {lambda} Orionis cluster is similar to those reported in other stellar groups with ages normally quoted as {approx}5 Myr.

Hernandez, Jesus [Centro de Investigaciones de AstronomIa, Apdo. Postal 264, Merida 5101-A (Venezuela, Bolivarian Republic of); Morales-Calderon, Maria [Laboratorio de Astrofisica Estelar y Exoplanetas (LAEX), Centro de Astrobiologia (CAB, INTA-CSIC), LAEFF, P.O. Box 78, E-28691, Villanueva de la canada, Madrid (Spain); Calvet, Nuria; Hartmann, L. [Department of Astronomy, University of Michigan, 830 Dennison Building, 500 Church Street, Ann Arbor, MI 48109 (United States); Muzerolle, J. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Gutermuth, R. [Five Colleges Astronomy Department, Smith College, Northampton, MA 01027 (United States); Luhman, K. L. [Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802 (United States); Stauffer, J., E-mail: hernandj@cida.v, E-mail: muzerol@stsci.ed [Spitzer Science Center, Caltech M/S 220-6, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

2010-10-20T23:59:59.000Z

307

Structural parameters for globular clusters in NGC 5128. III. ACS surface-brightness profiles and model fits  

E-Print Network (OSTI)

We present internal surface-brightness profiles, based on HST/ACS imaging in the F606W bandpass, for 131 globular cluster (GC) candidates with luminosities 10^4 - 3 x 10^6 solar, in the giant elliptical galaxy NGC 5128. Several structural models are fit to the profile of each cluster and combined with mass-to-light ratios from population-synthesis models, to derive a catalogue of fundamental structural and dynamical parameters parallel in form to the catalogues recently produced by McLaughlin & van der Marel and Barmby et al. for GCs and massive young star clusters in Local Group galaxies. As part of this, we provide corrected and extended parameter estimates for another 18 clusters in NGC 5128, which we observed previously. We show that, like GCs in the Milky Way and some of its satellites, the majority of globulars in NGC 5128 are well fit by isotropic Wilson models, which have intrinsically more distended envelope structures than the standard King lowered isothermal spheres. We use our models to predict internal velocity dispersions for every cluster in our sample. These predictions agree well in general with the observed dispersions in a small number of clusters for which spectroscopic data are available. In a subsequent paper, we use these results to investigate scaling relations for GCs in NGC 5128.

Dean E. McLaughlin; Pauline Barmby; William E. Harris; Duncan A. Forbes; Gretchen L. H. Harris

2007-11-14T23:59:59.000Z

308

Biomedical ontology improves biomedical literature clustering performance: a comparison study  

Science Conference Proceedings (OSTI)

Document clustering has been used for better document retrieval and text mining. In this paper, we investigate if a biomedical ontology improves biomedical literature clustering performance in terms of the effectiveness and the scalability. For this ... Keywords: MEDLINE, MeSH, bioinformatics, biomedical literature, biomedical ontology, comparison study, document clustering, document retrieval, information retrieval, text mining

Illhoi Yoo; Xiaohua Hu; Il-Yeol Song

2007-09-01T23:59:59.000Z

309

Large-scale clustering and complete facet and tag calculation  

Science Conference Proceedings (OSTI)

The State and University Library of Denmark is developing an integrated search system called Summa, and as part of the Summa project a clustering module and a facet module. Simple clusters have been created for a collection of more than six and a half ... Keywords: categorisation, clustering, faceted browsing, large data sets, library metadata

Bolette Ammitzbøll Madsen

2007-09-01T23:59:59.000Z

310

A Self-Organized Clustering Scheme for Overlay Networks  

Science Conference Proceedings (OSTI)

Hierarchical approaches, where nodes are clustered based on their network distances, have been shown to allow for robust and scalable topology-aware overlays. Moreover, recent research works have shown that cluster-based deployments of Internet Coordinates ... Keywords: Clustering, ICS, Performance, Triangle Inequality Violations

Francois Cantin; Bamba Gueye; Mohamed Ali Kaafar; Guy Leduc

2008-12-01T23:59:59.000Z

311

WireGL: a scalable graphics system for clusters  

Science Conference Proceedings (OSTI)

We describe WireGL, a system for scalable interactive rendering on a cluster of workstations. WireGL provides the familiar OpenGL API to each node in a cluster, virtualizing multiple graphics accelerators into a sort-first parallel renderer with a parallel ... Keywords: cluster rendering, parallel rendering, remote graphics, scalable rendering, tiled displays, virtual graphics

Greg Humphreys; Matthew Eldridge; Ian Buck; Gordan Stoll; Matthew Everett; Pat Hanrahan

2001-08-01T23:59:59.000Z

312

Towards green computing using diskless high performance clusters  

Science Conference Proceedings (OSTI)

In recent years, significant research has been conducted to boost the performance and increase the reliability of high performance computing (HPC) clusters. As the number of compute nodes in modern HPC clusters continues to grow, it is critical to design ... Keywords: Linux, cluster computing and architecture, green computing, performance evaluation

K. Salah; R. Al-Shaikh; M. Sindi

2011-10-01T23:59:59.000Z

313

Limiting the impact of mobility on ad hoc clustering  

Science Conference Proceedings (OSTI)

This paper explores the impact of node mobility on DMAC, a typical clustering protocol for mobile ad hoc networks. Several protocols for clustering have been proposed, which are quite similar in operations and performance. We selected one and ... Keywords: ad hoc networks, clustering protocols, mobility models

Rituparna Ghosh; Stefano Basagni

2005-10-01T23:59:59.000Z

314

Spectroscopic Elucidation of First Steps of Supported Bimetallic Cluster Formation  

DOE Green Energy (OSTI)

Initial steps of bimetallic Ru-Os cluster formation on MgO in the presence of H{sub 2} are analyzed by EXAFS and IR spectroscopy. Ru-Os bond formation takes place after decarbonylation of Ru{sub 3} clusters and subsequently, at higher temperatures, of Os{sub 3} clusters to generate coordinative unsaturation.

Kulkarni, A.; Gates, B.C.; (UCD)

2009-12-23T23:59:59.000Z

315

A merging clustering algorithm for mobile ad hoc networks  

Science Conference Proceedings (OSTI)

Clustering is a widely used approach to ease implementation of various problems such as routing and resource management in mobile ad hoc networks (MANET)s. We propose a new fully distributed algorithm for clustering in MANETs that merges clusters to ...

Orhan Dagdeviren; Kayhan Erciyes; Deniz Cokuslu

2006-05-01T23:59:59.000Z

316

Distributed Energy-Efficient Hierarchical Clustering for Wireless Sensor Networks  

E-Print Network (OSTI)

Distributed Energy-Efficient Hierarchical Clustering for Wireless Sensor Networks Ping Ding, Jo important. In this paper, we propose a distributed weight-based energy-efficient hierarchical clustering of the network topology. Younis and Fahmy [4] propose a Hybrid Energy-Efficient Distributed clustering (HEED

Holliday, JoAnne

317

Employing transport layer multi-railing in cluster networks  

Science Conference Proceedings (OSTI)

Building clusters from commodity off-the-shelf parts is a well-established technique for building inexpensive medium- to large-size computing clusters. Many commodity mid-range motherboards come with multiple Gigabit Ethernet interfaces, and the low ... Keywords: Cluster, Concurrent Multipath Transfer, MPI, Middleware, Multi-railing, Network interfaces, SCTP, TCP, Transport protocol

Brad Penoff; Humaira Kamal; Alan Wagner; Mike Tsai; Karol Mroz; Janardhan Iyengar

2010-03-01T23:59:59.000Z

318

On the statistical detection of clusters in undirected networks  

Science Conference Proceedings (OSTI)

The goal of network clustering algorithms is to assign each node in a network to one of several mutually exclusive groups based upon the observed edge set. Of the network clustering algorithms widely available, most make the effort to maximize the modularity ... Keywords: Community structure detection, Hypothesis testing, Log-likelihood, Log-likelihood ratio, Network clustering, Undirected networks

Marcus B. Perry, Gregory V. Michaelson, M. Alan Ballard

2013-12-01T23:59:59.000Z

319

Clusters, language models, and ad hoc information retrieval  

Science Conference Proceedings (OSTI)

The language-modeling approach to information retrieval provides an effective statistical framework for tackling various problems and often achieves impressive empirical performance. However, most previous work on language models for information retrieval ... Keywords: Language modeling, aspect models, cluster hypothesis, cluster-based language models, clustering, interpolation model, smoothing

Oren Kurland; Lillian Lee

2009-05-01T23:59:59.000Z

320

Clustering analysis of water quality for canals in bangkok, thailand  

Science Conference Proceedings (OSTI)

Two clustering techniques of water quality for canals in Bangkok were compared: K-means and Fuzzy c-means. The result illustrated that K-means has a better performance. As a result, K-means cluster was used to classify 24 canals of 344 records of surface ... Keywords: K-means clustering, surface water quality, watershed management

Sirilak Areerachakul; Siripun Sanguansintukul

2010-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Quantum frieze patterns in quantum cluster algebras of type A  

E-Print Network (OSTI)

We introduce a quantisation of the Coxeter-Conway frieze patterns and prove that they realise quantum cluster variables in quantum cluster algebras associated with linearly oriented Dynkin quivers of type A. As an application, we obtain the explicit polynomials arising from the lower bound phenomenon in these quantum cluster algebras.

Burelle, Jean-Philippe

2012-01-01T23:59:59.000Z

322

Workload-Aware Load Balancing for Clustered Web Servers  

Science Conference Proceedings (OSTI)

We focus on load balancing policies for homogeneous clustered Web servers that tune their parameters on-the-fly to adapt to changes in the arrival rates and service times of incoming requests. The proposed scheduling policy, AdaptLoad, monitors the incoming ... Keywords: Clustered Web servers, self-managing clusters, load balance, locality awareness, workload characterization, static and dynamic pages.

Qi Zhang; Alma Riska; Wei Sun; Evgenia Smirni; Gianfranco Ciardo

2005-03-01T23:59:59.000Z

323

Web Information Organization Using Keyword Distillation Based Clustering  

Science Conference Proceedings (OSTI)

This paper describes a system that conducts search result clustering for several thousands of Web pages, and elaborates cluster labels through keyword distillation. Keyword distillation is a method that properly handles spelling variations, transliterations, ... Keywords: clustering, open search engine, keyword unification

Tomohide Shibata; Yasuo Bamba; Keiji Shinzato; Sadao Kurohashi

2009-09-01T23:59:59.000Z

324

GLOBULAR CLUSTER ABUNDANCES FROM HIGH-RESOLUTION, INTEGRATED-LIGHT SPECTROSCOPY. III. THE LARGE MAGELLANIC CLOUD: Fe AND AGES  

Science Conference Proceedings (OSTI)

In this paper, we refine our method for the abundance analysis of high-resolution spectroscopy of the integrated light of unresolved globular clusters (GCs). This method was previously demonstrated for the analysis of old (>10 Gyr) Milky Way (MW) GCs. Here, we extend the technique to young clusters using a training set of nine GCs in the Large Magellanic Cloud. Depending on the signal-to-noise ratio of the data, we use 20-100 Fe lines per cluster to successfully constrain the ages of old clusters to within a {approx}5 Gyr range, the ages of {approx}2 Gyr clusters to a 1-2 Gyr range, and the ages of the youngest clusters (0.05-1 Gyr) to a {approx}200 Myr range. We also demonstrate that we can measure [Fe/H] in clusters with any age less than 12 Gyr with similar or only slightly larger uncertainties (0.1-0.25 dex) than those obtained for old MW GCs (0.1 dex); the slightly larger uncertainties are due to the rapid evolution in stellar populations at these ages. In this paper, we present only Fe abundances and ages. In the next paper in this series, we present our complete analysis of {approx}20 elements for which we are able to measure abundances. For several of the clusters in this sample, there are no high-resolution abundances in the literature from individual member stars; our results are the first detailed chemical abundances available. The spectra used in this paper were obtained at Las Campanas with the echelle on the du Pont Telescope and with the MIKE spectrograph on the Magellan Clay Telescope.

Colucci, Janet E.; Bernstein, Rebecca A. [Department of Astronomy and Astrophysics, 1156 High Street, UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Cameron, Scott A. [Astronomy Department, 500 Church Street, University of Michigan, Ann Arbor, MI 48109-1090 (United States); McWilliam, Andrew, E-mail: jcolucci@ucolick.org, E-mail: rab@ucolick.org, E-mail: sacamero@umich.edu, E-mail: andy@ociw.edu [The Observatories of the Carnegie Institute of Washington, 813 Santa Barbara Street, Pasadena, CA 91101-1292 (United States)

2011-07-01T23:59:59.000Z

325

Laboratory Access | Sample Preparation Laboratories  

NLE Websites -- All DOE Office Websites (Extended Search)

Access Access Planning Ahead Planning Ahead Please complete the Beam Time Request (BTR) and Support Request forms thourgh the User Portal. Thorough chemical and sample information must be included in your BTR. Support Request forms include a list of collaborators that require laboratory access and your group's laboratory equipment requests. Researcher safety is taken seriously at SLAC. Please remember that radioactive materials, nanomaterials, and biohazardous materials have additional safety requirements. Refer to the SSRL or LCLS Safety Offices for further guidance. Upon Arrival Upon Arrival Once you arrive you must complete training and access forms before accessing the Sample Preparation Laboratories (SPL). All Sample Prep Lab doors are locked with access key codes. Once your SPL

326

Definition: Surface Water Sampling | Open Energy Information  

Open Energy Info (EERE)

Water Sampling Jump to: navigation, search Dictionary.png Surface Water Sampling Water sampling is done to characterize the chemical, thermal, or hydrological properties of a...

327

Definition: Water Sampling | Open Energy Information  

Open Energy Info (EERE)

Sampling Jump to: navigation, search Dictionary.png Water Sampling Water sampling is done to characterize the chemical, thermal, or hydrological properties of a surface or...

328

A transduction-based approach to fuzzy clustering, relevance ranking and cluster label generation on web search results  

Science Conference Proceedings (OSTI)

This paper details a modular, self-contained web search results clustering system that enhances search results by (i) performing clustering on lists of web documents returned by queries to search engines, and (ii) ranking the results and labeling the ... Keywords: Fuzzy clustering, Label generation, Relevance transduction, Web search ranking

Takazumi Matsumoto; Edward Hung

2012-04-01T23:59:59.000Z

329

A New Census of the variable star population in the Globular Cluster NGC 2419  

E-Print Network (OSTI)

We present B, V and I CCD light curves for 101 variable stars belonging to the globular cluster NGC2419, 60 of which are new discoveries, based on datasets obtained at the TNG, SUBARU and HST telescopes. The sample includes 75 RR Lyrae stars (of which 38 RRab, 36 RRc and one RRd), one Population II Cepheid, 12 SX Phoenicis variables, 2 DeltaScuti stars, 3 binary systems, 5 long-period variables, and 3 variables of uncertain classification. The pulsation properties of the RR Lyrae variables are close to those of Oosterhoff type II clusters, consistent with the low metal abundance and the cluster horizontal branch morphology,disfavoring (but not totally ruling out) an extragalactic hypotesis for the origin of NGC2419. The observed properties of RR Lyrae and SX Phoenicis stars are used to estimate the cluster reddening and distance, using a number of different methods. Our final value is mo(NGC2419)=19.71+/-0.08mag (D= 87.5+/-3.3kpc), with E(B-V)=0.08+/-0.01mag, [Fe/H]=-2.1dex in the Zinn & West metallicity ...

Di Criscienzo, M; Ripepi, V; Clementini, G; Ora, M Dall'; Marconi, M; Musella, I; Federici, L; Di Fabrizio, L

2010-01-01T23:59:59.000Z

330

The unusually large population of Blazhko variables in the globular cluster NGC 5024 (M53)  

E-Print Network (OSTI)

We report the discovery of amplitude and phase modulations typical of the Blazhko effect in 22 RRc and 9 RRab type RR Lyrae stars in NGC 5024 (M53). This brings the confirmed Blazhko variables in this cluster to 23 RRc and 11 RRab, that represent 66% and 37% of the total population of RRc and RRab stars in the cluster respectively, making NGC 5024 the globular cluster with the largest presently known population of Blazhko RRc stars. We place a lower limit on the overall incidence rate of the Blazhko effect among the RR Lyrae population in this cluster of 52%. New data have allowed us to refine the pulsation periods. The limitations imposed by the time span and sampling of our data prevents reliable estimations of the modulation periods. The amplitudes of the modulations range between 0.02 and 0.39 mag. The RRab and RRc are neatly separated in the CMD, and the RRc Blazhko variables are on averge redder than their stable couterparts; these two facts may support the hypothesis that the HB evolution in this clust...

Ferro, A Arellano; Jaimes, R Figuera; Giridhar, Sunetra; Kuppuswamy, K

2011-01-01T23:59:59.000Z

331

An Iterative Rejection Sampling Method.  

E-Print Network (OSTI)

ar X iv :0 80 7. 28 23 v1 [ he p- ph ] 17 Ju l 2 00 8 Preprint typeset in JHEP style - HYPER VERSION Cavendish-HEP-08/10 An Iterative Rejection Sampling Method A. Sherstnev Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue... , Cambridge, CB3 0HE, UK and Scobeltsyn Institute of Nuclear Physics of Lomonosov Moscow State University, Moscow, Russia, 119992 (on leave) Abstract: In the note we consider an iterative generalisation of the rejection sampling method. In high energy physics...

Sherstnev, A

332

Temperature structure of the intergalactic medium within seven nearby and bright clusters of galaxies observed with XMM-Newton  

E-Print Network (OSTI)

Aims. We map the temperature structure of the intra-cluster medium (ICM) within a nearly complete X-ray flux limited sample of galaxy clusters in the redshift range z=[0.045,0.096]. Our sample contains seven bright clusters of galaxies observed with XMM-Newton: Abell 399, Abell 401, Abell 478, Abell 1795, Abell 2029, Abell 2065, Abell 2256. Methods. We use a multi-scale spectral mapping algorithm especially designed to map spectroscopic observables from X-ray extended emission of the ICM. Derived from a former algorithm using Haar wavelets, our algorithm is now implemented with B-spline wavelets in order to perform a more regular analysis of the signal. Results. For the four clusters in our sample that are major mergers, we find a complex thermal structure with strong thermal variations consistent with their dynamics. For two of them, A2065 and A2256, we perform a 3-d analysis of cold front features evidenced from the gas temperature and brightness maps. Furthermore, we detect a significant non-radial thermal structure outside the cool core region of the other 3 more "regular" clusters, with relative amplitudes of about about 10%. We investigate possible implications of this structure on the mass estimates of the "regular" clusters A1795 and A2029, by extracting surface brightness and temperature profiles from sectors correspondings to the hottest and coldest regions in the maps. While compensating with surface brightness for A2029, leading to consistent mass profiles, the temperature structure leads to significant mass discrepancies in the innermost region of A1795.

H. Bourdin; P. Mazzotta

2008-02-13T23:59:59.000Z

333

Visualization Clusters | Argonne Leadership Computing Facility  

NLE Websites -- All DOE Office Websites (Extended Search)

Eureka Eureka Analytics and Visualization Visualization Clusters Tukey Tukey is the ALCF's newest analysis and visualization cluster. Equipped with state-of-the-art graphics processing units (GPUs), Tukey converts computational data from Mira into high-resolution visual representations. The resulting images, videos, and animations help users to better analyze and understand the data generated by Mira. Tukey can also be used for statistical analysis, helping to pinpoint trends in the simulation data. Additionally, the system is capable of preprocessing efforts, such as meshing, to assist users preparing for Mira simulations. Tukey shares the Mira network and parallel file system, enabling direct access to Mira-generated results. Configuration Two 2 GHz 8-core AMD Opteron CPUs per node

334

How does clustering depend on environment?  

E-Print Network (OSTI)

According to the current paradigm, galaxies form and reside in extended cold dark matter (CDM) halos and in turn are key tracers of cosmological structure. Understanding how different types of galaxies occupy halos of different masses is one of the major challenges facing extragalactic astrophysics. The observed galaxy properties depend on the environment surrounding the galaxy. Within the framework of most galaxy formation models the environmental dependence of the galaxy population is mainly due to the change of the halo mass function with large-scale environment. Such models make precise predictions for how galaxy clustering should depend on environment. We will illustrate this by presenting analytical models of dark matter and galaxy clustering along with results obtained from numerical simulations. With these results we can hope to obtain a better understanding of the link between galaxies and dark matter and thereby constrain galaxy formation models.

Ummi Abbas; Ravi K. Sheth

2004-05-13T23:59:59.000Z

335

Graph clustering with network structure indices  

E-Print Network (OSTI)

Graph clustering has become ubiquitous in the study of relational data sets. We examine two simple algorithms: a new graphical adaptation of the k-medoids algorithm and the Girvan-Newman method based on edge betweenness centrality. We show that they can be effective at discovering the latent groups or communities that are defined by the link structure of a graph. However, both approaches rely on prohibitively expensive computations, given the size of modern relational data sets. Network structure indices (NSIs) are a proven technique for indexing network structure and efficiently finding short paths. We show how incorporating NSIs into these graph clustering algorithms can overcome these complexity limitations. We also present promising quantitative and qualitative evaluations of the modified algorithms on synthetic and real data sets. 1.

Matthew J. Rattigan; Marc Maier; David Jensen

2007-01-01T23:59:59.000Z

336

Synchronization and clustering in electroencephalographic signals  

E-Print Network (OSTI)

The degree of synchronization and the amount of dynamical cluster formation in electroencephalographic (EEG) signals are characterized by employing two order parameters introduced in the context of coupled chaotic systems subject to external noise. These parameters are calculated in EEG signals from a group of healthy subjects and a group of epileptic patients, including a patient experiencing an epileptic crisis. The evolution of these parameters shows the occurrence of intermittent synchronization and clustering in the brain activity during an epileptic crisis. Significantly, the existence of an instantaneous maximum of synchronization previous to the onset of a crisis is revealed by this procedure. The mean values of the order parameters and their standard deviations are compared between both groups of individuals.

M. Escalona-Moran; M. G. Cosenza; P. Guillen; P. Coutin

2005-06-07T23:59:59.000Z

337

A Thermodynamic Model for Receptor Clustering  

E-Print Network (OSTI)

Intracellular signaling often arises from ligand-induced oligomerization of cell surface receptors. This oligomerization or clustering process is fundamentally a cooperative behavior between near-neighbor receptor molecules; the properties of this cooperative process clearly affects the signal transduction. Recent investigations have revealed the molecular basis of receptor-receptor interactions, but a simple theoretical framework for using this data to predict cluster formation has been lacking. Here, we propose a simple, coarse-grained, phenomenological model for ligand-modulated receptor interactions and discuss its equilibrium properties via mean-field theory. The existence of a first-order transition for this model has immediate implications regarding the robustness of the cellular signaling response.

Chinlin Guo; Herbert Levine

1999-08-06T23:59:59.000Z

338

Measuring energy consumption of a database cluster  

E-Print Network (OSTI)

Abstract: Energy consumption of database servers is a growing concern for companies as it is a critical part of a data center’s cost. To address the rising cost and the waste of energy, a new paradigm called GreenIT arose. Hardware and software developers are aiming at more energy-efficient systems. To improve the energy footprint of database servers, we developed a cluster of small-scale nodes, that can be dynamically powered dependent on the workload. This demo shows the measurement framework we set up to measure hardware components as well as an entire cluster of nodes. We’ll exhibit the measurement devices for components and servers and show the system’s behavior under varying workloads. Attendees will be able to adjust workloads and experience their impact on energy consumption. 1

Volker Hudlet; Daniel Schall; Ag Dbis; Tu Kaiserslautern

2011-01-01T23:59:59.000Z

339

Discontinuous structure transition in a Debye cluster  

Science Conference Proceedings (OSTI)

We consider the structural phases of a cluster of identical particles confined in a two-dimensional biharmonic well and interacting through a screened Coulomb (Yukawa) potential (e.g., dusty plasma). For n = 6 particles, we show that there are one discontinuous and three continuous structure transitions, giving five structure phases. Two of these phases, the straight line and zigzag configurations, have previously been studied experimentally. We experimentally verify the discontinuous transition and observe the remaining three phases.

Sheridan, T. E. [Department of Physics and Astronomy, Ohio Northern University, Ada, Ohio 45810 (United States)

2012-05-15T23:59:59.000Z

340

Dynamics of Planetary Systems in Star Clusters  

E-Print Network (OSTI)

At least 10-15% of nearby sun-like stars have known Jupiter-mass planets. In contrast, very few planets are found in mature open and globular clusters such as the Hyades and 47 Tuc. We explore here the possibility that this dichotomy is due to the post-formation disruption of planetary systems associated with the stellar encounters in long-lived clusters. One supporting piece of evidence for this scenario is the discovery of freely floating low-mass objects in star forming regions. We use two independent numerical approaches, a hybrid Monte Carlo and a direct $N$-body method, to simulate the impact of the encounters. We show that the results of numerical simulations are in reasonable agreement with analytical determinations in the adiabatic and impulsive limits. They indicate that distant stellar encounters generally do not significantly modify the compact and nearly circular orbits. However, moderately close stellar encounters, which are likely to occur in dense clusters, can excite planets' orbital eccentricity and induce dynamical instability in systems which are closely packed with multiple planets. We compute effective cross sections for the dissolution of planetary systems and show that, for all initial eccentricities, dissolution occurs on time scales which are longer than the dispersion of small stellar associations, but shorter than the age of typical open and globular clusters. Although it is much more difficult to disrupt short-period planets, close encounters can excite modest eccentricity among them, such that subsequent tidal dissipation leads to orbital decay, tidal inflation, and even disruption of the close-in planets.

R. Spurzem; M. Giersz; D. C. Heggie; D. N. C. Lin

2006-12-28T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

SIMILARITIES IN POPULATIONS OF STAR CLUSTERS  

SciTech Connect

We compare the observed mass functions and age distributions of star clusters in six well-studied galaxies: the Milky Way, Magellanic Clouds, M83, M51, and Antennae. In combination, these distributions span wide ranges of mass and age: 10{sup 2} {approx}< M/M{sub Sun} {approx}< 10{sup 6} and 10{sup 6} {approx}< {tau}/yr {approx}< 10{sup 9}. We confirm that the distributions are well represented by power laws: dN/dM{proportional_to}M{sup {beta}} with {beta} Almost-Equal-To -1.9 and dN/d{tau}{proportional_to}{tau}{sup {gamma}} with {gamma} Almost-Equal-To -0.8. The mass and age distributions are approximately independent of each other, ruling out simple models of mass-dependent disruption. As expected, there are minor differences among the exponents at a level close to the true uncertainties, {epsilon}{sub {beta}} {approx} {epsilon}{sub {gamma}} {approx} 0.1-0.2. However, the overwhelming impression is the similarity of the mass functions and age distributions of clusters in these different galaxies, including giant and dwarf, quiescent and interacting galaxies. This is an important empirical result, justifying terms such as 'universal' or 'quasi-universal'. We provide a partial theoretical explanation for these observations in terms of physical processes operating during the formation and disruption of the clusters, including star formation and feedback, subsequent stellar mass loss, and tidal interactions with passing molecular clouds. A full explanation will require additional information about the molecular clumps and star clusters in galaxies beyond the Milky Way.

Fall, S. Michael [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Chandar, Rupali, E-mail: fall@stsci.edu, E-mail: rupali.chandar@utoledo.edu [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States)

2012-06-20T23:59:59.000Z

342

STAR FORMATION EFFICIENCY IN THE COOL CORES OF GALAXY CLUSTERS  

SciTech Connect

We have assembled a sample of high spatial resolution far-UV (Hubble Space Telescope Advanced Camera for Surveys/Solar Blind Channel) and H{alpha} (Maryland-Magellan Tunable Filter) imaging for 15 cool core galaxy clusters. These data provide a detailed view of the thin, extended filaments in the cores of these clusters. Based on the ratio of the far-UV to H{alpha} luminosity, the UV spectral energy distribution, and the far-UV and H{alpha} morphology, we conclude that the warm, ionized gas in the cluster cores is photoionized by massive, young stars in all but a few (A1991, A2052, A2580) systems. We show that the extended filaments, when considered separately, appear to be star forming in the majority of cases, while the nuclei tend to have slightly lower far-UV luminosity for a given H{alpha} luminosity, suggesting a harder ionization source or higher extinction. We observe a slight offset in the UV/H{alpha} ratio from the expected value for continuous star formation which can be modeled by assuming intrinsic extinction by modest amounts of dust (E(B - V) {approx} 0.2) or a top-heavy initial mass function in the extended filaments. The measured star formation rates vary from {approx}0.05 M{sub sun} yr{sup -1} in the nuclei of non-cooling systems, consistent with passive, red ellipticals, to {approx}5 M{sub sun} yr{sup -1} in systems with complex, extended, optical filaments. Comparing the estimates of the star formation rate based on UV, H{alpha}, and infrared luminosities to the spectroscopically determined X-ray cooling rate suggests a star formation efficiency of 14{sup +18}{sub -8}%. This value represents the time-averaged fraction, by mass, of gas cooling out of the intracluster medium, which turns into stars and agrees well with the global fraction of baryons in stars required by simulations to reproduce the stellar mass function for galaxies. This result provides a new constraint on the efficiency of star formation in accreting systems.

McDonald, Michael; Veilleux, Sylvain; Mushotzky, Richard; Reynolds, Christopher [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Rupke, David S. N., E-mail: mcdonald@astro.umd.edu, E-mail: veilleux@astro.umd.edu [Department of Physics, Rhodes College, Memphis, TN 38112 (United States)

2011-06-20T23:59:59.000Z

343

Additive spectral method for fuzzy cluster analysis of similarity data including community structure and affinity matrices  

Science Conference Proceedings (OSTI)

An additive spectral method for fuzzy clustering is proposed. The method operates on a clustering model which is an extension of the spectral decomposition of a square matrix. The computation proceeds by extracting clusters one by one, which makes the ... Keywords: Additive fuzzy clustering, Community structure, Lapin transformation, One-by-one clustering, Research activity structure, Spectral fuzzy clustering

Boris Mirkin; Susana Nascimento

2012-01-01T23:59:59.000Z

344

Effective Graph Clustering for Path Queries in Digital Map Databases  

E-Print Network (OSTI)

In this paper, we present an experimental evaluation of graph clustering strategies in terms of their effectiveness in optimizing I/O for path query processing in digital map databases. Clustering optimization is attractive because it does not incurs any run-time cost, and is complimentary to many of the existing techniques in path query optimization. We first propose a novel graph clustering technique, called Spatial Partition Clustering (SPC), that creates balanced partitions of links based on the spatial proximity of their origin nodes. We then select three alternative clustering techniques from the literature, namely two-way partitioning, approximately topological clustering, and random clustering, to compare their performance in path query processing with SPC. Experimental evaluation indicates that our SPC performs the best for the high-locality graphs (such as GIS maps), whereas the two-way partitioning approach performs the best for no-locality random graphs. 1 Introduction 1....

Yun-Wu Huang; Ning Jing; Elke A. Rundensteiner

1996-01-01T23:59:59.000Z

345

AUTOMATING GROUNDWATER SAMPLING AT HANFORD  

Science Conference Proceedings (OSTI)

Until this past October, Fluor Hanford managed Hanford's integrated groundwater program for the U.S. Department of Energy (DOE). With the new contract awards at the Site, however, the CH2M HILL Plateau Remediation Company (CHPRC) has assumed responsibility for the groundwater-monitoring programs at the 586-square-mile reservation in southeastern Washington State. These programs are regulated by the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response Compensation and Liability Act (CERCLA). The purpose of monitoring is to track existing groundwater contamination from past practices, as well as other potential contamination that might originate from RCRA treatment, storage, and disposal (TSD) facilities. An integral part of the groundwater-monitoring program involves taking samples of the groundwater and measuring the water levels in wells scattered across the site. More than 1,200 wells are sampled each year. Historically, field personnel or 'samplers' have been issued pre-printed forms that have information about the well(s) for a particular sampling evolution. This information is taken from the Hanford Well Information System (HWIS) and the Hanford Environmental Information System (HEIS)--official electronic databases. The samplers used these hardcopy forms to document the groundwater samples and well water-levels. After recording the entries in the field, the samplers turned the forms in at the end of the day and the collected information was posted onto a spreadsheet that was then printed and included in a log book. The log book was then used to make manual entries of the new information into the software application(s) for the HEIS and HWIS databases. This is a pilot project for automating this tedious process by providing an electronic tool for automating water-level measurements and groundwater field-sampling activities. The automation will eliminate the manual forms and associated data entry, improve the accuracy of the information recorded, and enhance the efficiency and sampling capacity of field personnel. The goal of the effort is to eliminate 100 percent of the manual input to the database(s) and replace the management of paperwork by the field and clerical personnel with an almost entirely electronic process. These activities will include the following: scheduling the activities of the field teams, electronically recording water-level measurements, electronically logging and filing Groundwater Sampling Reports (GSR), and transferring field forms into the site-wide Integrated Document Management System (IDMS).

CONNELL CW; HILDEBRAND RD; CONLEY SF; CUNNINGHAM DE

2009-01-16T23:59:59.000Z

346

Model-Based Sampling, Inference and Imputation  

Reports and Publications (EIA)

Picking a sample through some randomization mechanism, such as random sampling withingroups (stratified random sampling), or, say, sampling every fifth item (systematic randomsampling), may be familiar to a lot of people.

Information Center

2012-03-13T23:59:59.000Z

347

Model-Based Sampling, Inference and Imputation  

Reports and Publications (EIA)

Picking a sample through some randomization mechanism, such as random sampling withingroups (stratified random sampling), or, say, sampling every fifth item (systematic randomsampling), may be familiar to a lot of people.

Neal Davis

2013-09-18T23:59:59.000Z

348

Star Formation Rates in Cooling Flow Clusters: A UV Pilot Study with Archival XMM-Newton Optical Monitor Data  

E-Print Network (OSTI)

We have analyzed XMM-Newton Optical Monitor (OM) UV (180-400 nm) data for a sample of 33 galaxies, of which 30 are cluster members. Nine of these are central cluster galaxies (CCGs) in cooling flow clusters, having mass deposition rates which span a range of 8 to 525 solar masses per year. Using the ratio of UV to 2MASS J band flux, we find a significant UV excess in many, but not all, cooling flow CCGs. This UV excess is a direct indication of the presence of young massive stars, and therefore recent star formation, in these galaxies. Using the Starburst99 spectral energy distribution (SED) model of continuous star formation over a 900 Myr period, we derive star formation rates of 0.2 to 219 solar masses per year for the cooling flow sample. For 2/3 of this sample it is possible to equate Chandra/XMM cooling flow mass deposition rates with UV inferred star formation rates, for a combination of starburst lifetime and IMF slope. This is a pilot study of the well populated XMM UV cluster archive and a more extensive follow up study is currently underway.

Amalia K. Hicks; Richard Mushotzky

2005-08-04T23:59:59.000Z

349

The Clustering of Galaxies in the SDSS-III DR9 Baryon Oscillation Spectroscopic Survey: Testing Deviations from $\\Lambda$ and General Relativity using anisotropic clustering of galaxies  

E-Print Network (OSTI)

We use the joint measurement of geometry and growth from anisotropic galaxy clustering in the Baryon Oscillation Spectroscopic Survey Data Release 9 CMASS sample reported in \\citet{Reid12} to constrain dark energy properties and possible deviations from the General Relativity. Assuming GR and taking a prior on the linear matter power spectrum at high redshift from the cosmic microwave background (CMB), anisotropic clustering of the CMASS DR9 galaxies alone constrains $\\Omega_{\\rm m} = 0.308 \\pm 0.022$ and $100\\Omega_{\\rm k} = 5.9 \\pm 4.8$ for $w = -1$, or $w = -0.91 \\pm 0.12$ for $\\Omega_k = 0$. When combined with the full CMB likelihood, the addition of the anisotropic clustering measurements to the spherically-averaged BAO location increases the constraining power on dark energy by a factor of 4 in a flat CDM cosmology with constant dark energy equation of state $w$ (giving $w = -0.87 \\pm 0.05$). This impressive gain depends on our measurement of both the growth of structure and Alcock-Paczynski effect, and...

Samushia, Lado; White, Martin; Percival, Will J; Cuesta, Antonio J; Lombriser, Lucas; Manera, Marc; Nichol, Robert C; Schneider, Donald P; Bizyaev, Dmitry; Brewington, Howard; Malanushenko, Elena; Malanushenko, Viktor; Oravetz, Daniel; Pan, Kaike; Simmons, Audrey; Shelden, Alaina; Snedden, Stephanie; Tinker, Jeremy L; Weaver, Benjamin A; York, Donald G; Zhao, Gong-Bo

2012-01-01T23:59:59.000Z

350

An Iterative Rejection Sampling Method  

E-Print Network (OSTI)

In the note we consider an iterative generalisation of the rejection sampling method. In high energy physics, this sampling is frequently used for event generation, i.e. preparation of phase space points distributed according to a matrix element squared $|M|^2$ for a scattering process. In many realistic cases $|M|^2$ is a complicated multi-dimensional function, so, the standard von Neumann procedure has quite low efficiency, even if an error reducing technique, like VEGAS, is applied. As a result of that, many of the $|M|^2$ calculations go to ``waste''. The considered iterative modification of the procedure can extract more ``unweighted'' events, i.e. distributed according to $|M|^2$. In several simple examples we show practical benefits of the technique and obtain more events than the standard von Neumann method, without any extra calculations of $|M|^2$.

A. Sherstnev

2008-07-17T23:59:59.000Z

351

Chemical Resources | Sample Preparation Laboratories  

NLE Websites -- All DOE Office Websites (Extended Search)

Chemical Resources Chemical Resources Chemical Inventory All Sample Preparation Labs are stocked with an assortment of common solvents, acids, bases, buffers, and other reagents. See our Chemical Inventories for a list of available reagents. If you need large quantities of any chemicals, please order or bring your own supply (see below). Chemical Inventories Standard Operating Procedures (SOPs) If you will be working with any samples or reagents that are significantly toxic, reactive, corrosive, flammable, or otherwise especially hazardous, we may require an approved SOP before you can begin work. Examples: Reagents with an NFPA Rating of 3 or 4 in any category, nanomaterials, heavy metals, pyrophoric materials, water reactive materials. BLANK SOP SSRL BLANK SOP LCLS Ordering Chemicals

352

Respiratory motion sampling in 4DCT reconstruction for radiotherapy  

SciTech Connect

Purpose: Phase-based and amplitude-based sorting techniques are commonly used in four-dimensional CT (4DCT) reconstruction. However, effect of these sorting techniques on 4D dose calculation has not been explored. In this study, the authors investigated a candidate 4DCT sorting technique by comparing its 4D dose calculation accuracy with that for phase-based and amplitude-based sorting techniques.Method: An optimization model was formed using organ motion probability density function (PDF) in the 4D dose convolution. The objective function for optimization was defined as the maximum difference between the expected 4D dose in organ of interest and the 4D dose calculated using a 4DCT sorted by a candidate sampling method. Sorting samples, as optimization variables, were selected on the respiratory motion PDF assessed during the CT scanning. Breathing curves obtained from patients' 4DCT scanning, as well as 3D dose distribution from treatment planning, were used in the study. Given the objective function, a residual error analysis was performed, and k-means clustering was found to be an effective sampling scheme to improve the 4D dose calculation accuracy and independent with the patient-specific dose distribution. Results: Patient data analysis demonstrated that the k-means sampling was superior to the conventional phase-based and amplitude-based sorting and comparable to the optimal sampling results. For phase-based sorting, the residual error in 4D dose calculations may not be further reduced to an acceptable accuracy after a certain number of phases, while for amplitude-based sorting, k-means sampling, and the optimal sampling, the residual error in 4D dose calculations decreased rapidly as the number of 4DCT phases increased to 6.Conclusion: An innovative phase sorting method (k-means method) is presented in this study. The method is dependent only on tumor motion PDF. It could provide a way to refine the phase sorting in 4DCT reconstruction and is effective for 4D dose accumulation. Optimized sorting techniques could achieve acceptable residuals (less than 0.5% of the prescription dose) using 6 sorting samples, which is much better than amplitude-based or phase-based sorting. Further increase in sorting phase number exceeding 6 or more may not be necessary when using the k-means sampling or optimal sampling points.

Chi Yuwei; Liang Jian; Qin Xu; Yan Di [Department of Radiation Oncology, Columbia University, New York, New York 10032 (United States); Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, Michigan 48073 (United States)

2012-04-15T23:59:59.000Z

353

Techniques for multivariate sample design  

SciTech Connect

In this report we consider sampling methods applicable to the multi-product Annual Fuel Oil and Kerosene Sales Report (Form EIA-821) Survey. For years prior to 1989, the purpose of the survey was to produce state-level estimates of total sales volumes for each of five target variables: residential No. 2 distillate, other retail No. 2 distillate, wholesale No. 2 distillate, retail residual, and wholesale residual. For the year 1989, the other retail No. 2 distillate and wholesale No. 2 distillate variables were replaced by a new variable defined to be the maximum of the two. The strata for this variable were crossed with the strata for the residential No. 2 distillate variable, resulting in a single stratified No. 2 distillate variable. Estimation for 1989 focused on the single No. 2 distillate variable and the two residual variables. Sampling accuracy requirements for each product were specified in terms of the coefficients of variation (CVs) for the various estimates based on data taken from recent surveys. The target population for the Form EIA-821 survey includes companies that deliver or sell fuel oil or kerosene to end-users. The Petroleum Product Sales Identification Survey (Form EIA-863) data base and numerous state and commercial lists provide the basis of the sampling frame, which is updated as new data become available. In addition, company/state-level volumes for distillates fuel oil, residual fuel oil, and motor gasoline are added to aid the design and selection process. 30 refs., 50 figs., 10 tabs.

Williamson, M.A.

1990-04-01T23:59:59.000Z

354

CONSTRAINTS ON DARK MATTER ANNIHILATION IN CLUSTERS OF GALAXIES FROM DIFFUSE RADIO EMISSION  

SciTech Connect

Annihilation of dark matter can result in the production of stable Standard Model particles including electrons and positrons that, in the presence of magnetic fields, lose energy via synchrotron radiation, observable as radio emission. Galaxy clusters are excellent targets to search for or to constrain the rate of dark matter annihilation, as they are both massive and dark matter dominated. In this study, we place limits on dark matter annihilation in a sample of nearby clusters using upper limits on the diffuse radio emission, low levels of observed diffuse emission, or detections of radio mini-halos. We find that the strongest limits on the annihilation cross section are better than limits derived from the non-detection of clusters in the gamma-ray band by a factor of {approx}3 or more when the same annihilation channel and substructure model, but different best-case clusters, are compared. The limits on the cross section depend on the assumed amount of substructure, varying by as much as two orders of magnitude for increasingly optimistic substructure models as compared to a smooth Navarro-Frenk-White profile. In our most optimistic case, using the results of the Phoenix Project, we find that the derived limits reach below the thermal relic cross section of 3 Multiplication-Sign 10{sup -26} cm{sup 3} s{sup -1} for dark matter masses as large as 400 GeV, for the b b-bar annihilation channel. We discuss uncertainties due to the limited available data on the magnetic field structure of individual clusters. We also report the discovery of diffuse radio emission from the central 30-40 kpc regions of the groups M49 and NGC 4636.

Storm, Emma; Jeltema, Tesla E.; Profumo, Stefano [Department of Physics, University of California, 1156 High St., Santa Cruz, CA 95064 (United States); Rudnick, Lawrence [Minnesota Institute for Astrophysics, School of Physics and Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States)

2013-05-10T23:59:59.000Z

355

Migration Mechanisms of Oxygen Interstitial Clusters in UO2  

Science Conference Proceedings (OSTI)

Understanding the migration kinetics of radiation-induced point defects and defect clusters is a key to predicting the microstructural evolution and mass transport in nuclear fuels. Although the diffusion kinetics of point defects in UO2 is well explored both experimentally and theoretically, the kinetics of defect clusters is not well understood. In this work the migration mechanisms of oxygen interstitial clusters of size one to five atoms (1Oi – 5Oi) in UO2 are investigated by temperature-accelerated dynamics simulations without any a priori assumptions of migration mechanisms. It is found that the migration paths of oxygen interstitial clusters are complex and non-intuitive and that multiple migration paths and barriers exist for some clusters. It is also found that the cluster migration barrier does not increase with increasing cluster size and its magnitude has the following order: 2Oi < 3Oi < 1Oi < 5Oi < 4Oi. Possible finite-size effects are checked with three different sized systems. The results show good agreement with other available experimental and theoretical data. In particular, the relatively large migration barriers of cuboctahedral clusters (4Oi and 5Oi) are in good agreement with the experimentally measured oxygen diffusion activation energy in U4O9, which is thought to contain many such clusters. The cluster migration sequence may explain the interesting relationship between the oxygen diffusivity and stoichiometry in UO2+x.

Xian-Ming Bai; Anter El-Azab; Jianguo Yu; Todd R. Allen

2013-01-01T23:59:59.000Z

356

Time Series Photometry of Variable Stars in the Globular Cluster NGC 6397  

E-Print Network (OSTI)

Time series BVI photometry is presented for 16 short-period variables located in the central region of the globular cluster NGC 6397. The sample includes 9 newly detected variables. The light curve of cataclysmic variable CV6 shows variability with a period of 0.2356 days. We confirm an earlier reported period of 0.472 days for cataclysmic variable CV1. Phased light curves of both CVs exhibit sine-like light curves, with two minima occurring during each orbital cycle. The secondary component of CV1 has a low average density of 0.83 g/cm^{3} indicating that it cannot be a normal main sequence star. Variables among the cluster blue stragglers include a likely detached eclipsing binary with orbital period of 0.787 days, three new SX Phe stars (one of which has the extremely short period of 0.0215 days), and three low amplitude variables which are possible gamma Doradus variables.

Janusz Kaluzny; Ian B. Thompson

2002-10-29T23:59:59.000Z

357

PROSPECTS FOR MEASURING THE RELATIVE VELOCITIES OF GALAXY CLUSTERS IN PHOTOMETRIC SURVEYS USING THE KINETIC SUNYAEV-ZEL'DOVICH EFFECT  

SciTech Connect

We consider the prospects for measuring the pairwise kinetic Sunyaev-Zel'dovich (kSZ) signal from galaxy clusters discovered in large photometric surveys such as the Dark Energy Survey (DES). We project that the DES cluster sample will, in conjunction with existing mm-wave data from the South Pole Telescope (SPT), yield a detection of the pairwise kSZ signal at the 8{sigma}-13{sigma} level, with sensitivity peaking for clusters separated by {approx}100 Mpc distances. A next-generation version of SPT would allow for a 18{sigma}-30{sigma} detection and would be limited by variance from the kSZ signal itself and the residual thermal Sunyaev-Zel'dovich (tSZ) signal. Throughout our analysis, we assume photometric redshift errors that wash out the signal for clusters separated by {approx}<50 Mpc; a spectroscopic survey of the DES sample would recover this signal and allow for a 26{sigma}-43{sigma} detection, and would again be limited by kSZ/tSZ variance. Assuming a standard model of structure formation, these high-precision measurements of the pairwise kSZ signal will yield detailed information on the gas content of the galaxy clusters. Alternatively, if the gas can be sufficiently characterized by other means (e.g., using tSZ, X-ray, or weak lensing), then the relative velocities of the galaxy clusters can be isolated, thereby providing a precision measurement of gravity on 100 Mpc scales. We briefly consider the utility of these measurements for constraining theories of modified gravity.

Keisler, Ryan [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Schmidt, Fabian, E-mail: rkeisler@uchicago.edu, E-mail: fabians@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08540 (United States)

2013-03-10T23:59:59.000Z

358

Clustering Properties of Dynamical Dark Energy Models  

E-Print Network (OSTI)

We provide a generic but physically clear discussion of the clustering properties of dark energy models. We explicitly show that in quintessence-type models the dark energy fluctuations, on scales smaller than the Hubble radius, are of the order of the perturbations to the Newtonian gravitational potential, hence necessarily small on cosmological scales. Moreover, comparable fluctuations are associated with different gauge choices. We also demonstrate that the often used homogeneous approximation is unrealistic, and that the so-called dark energy mutation is a trivial artifact of an effective, single fluid description. Finally, we discuss the particular case where the dark energy fluid is coupled to dark matter.

P. P. Avelino; L. M. G. Beca; C. J. A. P. Martins

2008-02-01T23:59:59.000Z

359

MgO-Supported Cluster Catalysts with Pt-Ru Interactions Prepared from Pt3Ru6(CO)21(u3-H)(u-H)3  

Science Conference Proceedings (OSTI)

Bimetallic MgO-supported catalysts were prepared by adsorption of Pt{sub 3}Ru{sub 6}(CO){sub 21}({mu}{sub 3}-H)({mu}-H){sub 3} on porous MgO. Characterization of the supported clusters by infrared (IR) spectroscopy showed that the adsorbed species were still in the form of metal carbonyls. The supported clusters were decarbonylated by treatment in flowing helium at 300 C, as shown by IR and extended X-ray absorption fine structure (EXAFS) data, and the resulting supported PtRu clusters were shown by EXAFS spectroscopy to have metal frames that retained Pt-Ru bonds but were slightly restructured relative to those of the precursor; the average cluster size was almost unchanged as a result of the decarbonylation. These are among the smallest reported bimetallic clusters of group-8 metals. The decarbonylated sample catalyzed ethylene hydrogenation with an activity similar to that reported previously for {gamma}-Al{sub 2}O{sub 3}-supported clusters prepared in nearly the same way and having nearly the same structure. Both samples were also active for n-butane hydrogenolysis, with the MgO-supported catalyst being more active than the {gamma}-Al{sub 2}O{sub 3}-supported catalyst.

Chotisuwan,S.; Wittapyakun, J.; Lobo-Lapidus, R.; Gates, B.

2007-01-01T23:59:59.000Z

360

Understanding High-Temperature Superconductors with Quantum Cluster Theories  

SciTech Connect

Quantum cluster theories are a set of approaches for the theory of correlated and disordered lattice systems, which treat correlations within the cluster explicitly, and correlations at longer length scales either perturbatively or within a mean-field approximation. These methods become exact when the cluster size diverges, and most recover the corresponding (dynamical) mean-field approximation when the cluster size becomes one. Here we will review systematic dynamical cluster simulations of the two-dimensional Hubbard model, that display phenomena remarkably similar to those found in the cuprates, including antiferromagnetism, superconductivity and pseudogap behavior. We will then discuss results for the structure of the pairing mechanism in this model, obtained from a combination of dynamical cluster results and diagrammatic techniques.

Maier, Thomas A [ORNL; Jarrell, Mark [University of Cincinnati; Scalapino, Douglas [University of California, Santa Barbara

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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We encourage you to perform a real-time search of NLEBeta
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361

Electronic Structure and Geometries of Small Compound Metal Clusters  

DOE Green Energy (OSTI)

During the tenure of the DOE grant DE-FG05-87EI145316 we have concentrated on equilibrium geometries, stability, and the electronic structure of transition metal-carbon clusters (met-cars), clusters designed to mimic the chemistry of atoms, and reactivity of homo-nuclear metal clusters and ions with various reactant molecules. It is difficult to describe all the research the authors have accomplished as they have published 38 papers. In this report, they outline briefly the salient features of their work on the following topics: (1) Designer Clusters: Building Blocks for a New Class of Solids; (2) Atomic Structure, Stability, and Electronic Properties of Metallo-Carbohedrenes; (3) Reactivity of Metal Clusters with H{sub 2} and NO; and (4) Anomalous Spectroscopy of Li{sub 4} Clusters.

NONE

1999-04-14T23:59:59.000Z

362

Magnetometry with entangled atomic samples  

E-Print Network (OSTI)

We present a theory for the estimation of a scalar or a vector magnetic field by its influence on an ensemble of trapped spin polarized atoms. The atoms interact off-resonantly with a continuous laser field, and the measurement of the polarization rotation of the probe light, induced by the dispersive atom-light coupling, leads to spin-squeezing of the atomic sample which enables an estimate of the magnetic field which is more precise than that expected from standard counting statistics. For polarized light and polarized atoms, a description of the non-classical components of the collective spin angular momentum for the atoms and the collective Stokes vectors of the light-field in terms of effective gaussian position and momentum variables is practically exact. The gaussian formalism describes the dynamics of the system very effectively and accounts explicitly for the back-action on the atoms due to measurement and for the estimate of the magnetic field. Multi-component magnetic fields are estimated by the measurement of suitably chosen atomic observables and precision and efficiency is gained by dividing the atomic gas in two or more samples which are entangled by the dispersive atom-light interaction.

Vivi Petersen; Lars Bojer Madsen; Klaus Molmer

2004-09-28T23:59:59.000Z

363

GAS SURFACE DENSITY, STAR FORMATION RATE SURFACE DENSITY, AND THE MAXIMUM MASS OF YOUNG STAR CLUSTERS IN A DISK GALAXY. I. THE FLOCCULENT GALAXY M 33  

Science Conference Proceedings (OSTI)

We analyze the relationship between maximum cluster mass M{sub max} and surface densities of total gas ({Sigma}{sub gas}), molecular gas ({Sigma}{sub H{sub 2}}), and star formation rate ({Sigma}{sub SFR}) in the flocculent galaxy M 33, using published gas data and a catalog of more than 600 young star clusters in its disk. By comparing the radial distributions of gas and most massive cluster masses, we find that M{sub max}{proportional_to}{Sigma}{sup 4.7{+-}0.4}{sub gas}, M{sub max}{proportional_to}{Sigma}{sup 1.3{+-}0.1}{sub H{sub 2}}, and M{sub max}{proportional_to}{Sigma}{sup 1.0{+-}0.1}{sub SFR}. We rule out that these correlations result from the size of the sample; hence, the change of the maximum cluster mass must be due to physical causes.

Gonzalez-Lopezlira, Rosa A.; Pflamm-Altenburg, Jan; Kroupa, Pavel, E-mail: r.gonzalez@crya.unam.mx [Argelander Institut fuer Astronomie, Universitaet Bonn, Auf dem Huegel 71, D-53121 Bonn (Germany)

2012-12-20T23:59:59.000Z

364

Leverage Causes Fat Tails and Clustered Volatility  

E-Print Network (OSTI)

We build a very simple model of leveraged asset purchases with margin calls. Investment funds use what is perhaps the most basic financial strategy, called 'value investing', i.e. systematically attempting to buy underpriced assets. When funds do not borrow, the price fluctuations of the asset are normally distributed and uncorrelated across time. All this changes when the funds are allowed to leverage, i.e. borrow from a bank, to purchase more assets than their wealth would otherwise permit. When funds use leverage, price fluctuations become heavy tailed and display clustered volatility, similar to what is observed in real markets. Previous explanations of fat tails and clustered volatility depended on 'irrational behavior', such as trend following. We show that the immediate cause of the increase in extreme risks in our model is the risk control policy of the banks: A prudent bank makes itself locally safer by putting a limit to leverage, so when a fund exceeds its leverage limit, it must partially repay it...

Thurner, Stefan; Geanakoplos, John

2009-01-01T23:59:59.000Z

365

Fast identification of gene clusters in prokaryotic genomes - CECM  

E-Print Network (OSTI)

support can hide some parts of interesting clusters, if the data set contains ... We now describe the application of our algorithm to a data set composed of 12 ...

366

Formal models of gene clusters - CECM - Simon Fraser University  

E-Print Network (OSTI)

The detection of conserved gene clusters is a challenge for both the biologi- ..... depending on both the combinatorial nature of the considered data (strings or.

367

The global optimization of Morse clusters by potential energy ...  

E-Print Network (OSTI)

Jul 15, 2003 ... The global optimization of Morse clusters by potential energy ... increase the efficiency in locating the known global minima and also to discover ...

368

Theoretical Investigation on Interplay of Defect Clusters and Fission ...  

Science Conference Proceedings (OSTI)

A prominent effect of the self-defect clusters in bulk matrix on the thermodynamic behavior of fission gases is found, a thermodynamic competition between the ...

369

Model-Based Sampling and Inference  

U.S. Energy Information Administration (EIA) Indexed Site

Model-Based Sampling, Inference and Imputation Model-Based Sampling, Inference and Imputation James R. Knaub, Jr., Energy Information Administration, EI-53.1 James.Knaub@eia.doe.gov Key Words: Survey statistics, Randomization, Conditionality, Random sampling, Cutoff sampling Abstract: Picking a sample through some randomization mechanism, such as random sampling within groups (stratified random sampling), or, say, sampling every fifth item (systematic random sampling), may be familiar to a lot of people. These are design-based samples. Estimates of means and totals for an entire population may be inferred from such a sample, along with estimation of the amount of error that might be expected. However, inference based on a sample and its (modeled) relationship to other data may be less familiar. If there is enough

370

Definition: Gas Flux Sampling | Open Energy Information  

Open Energy Info (EERE)

Gas Flux Sampling Jump to: navigation, search Dictionary.png Gas Flux Sampling Gas flux sampling measures the flow of volatile gas emissions from a specific location and compares...

371

Licensing Guide and Sample License  

NLE Websites -- All DOE Office Websites (Extended Search)

TEI:HNOL06Y TRANSFER WORKIN6 6ROUP TEI:HNOL06Y TRANSFER WORKIN6 6ROUP Lic:en!iing Guide and Sample Lic:en!ie ·~ ICan.u City Plan I OFermilab ~OAK ~RIDGE Nuioul~.

372

Surface Water Sampling | Open Energy Information  

Open Energy Info (EERE)

Surface Water Sampling Surface Water Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Surface Water Sampling Details Activities (1) Areas (1) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Field Sampling Parent Exploration Technique: Water Sampling Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Water composition and source of fluids Thermal: Water temperature Dictionary.png Surface Water Sampling: Water sampling is done to characterize the chemical, thermal, or hydrological properties of a surface or subsurface aqueous system. Other definitions:Wikipedia Reegle Introduction Surface water sampling of hot and cold spring discharges has traditionally

373

Definition: Groundwater Sampling | Open Energy Information  

Open Energy Info (EERE)

Dictionary.png Groundwater Sampling Groundwater sampling is done to characterize the chemical, thermal, or hydrological properties of subsurface aqueous systems. Groundwater...

374

Definition: Surface Gas Sampling | Open Energy Information  

Open Energy Info (EERE)

search Dictionary.png Surface Gas Sampling Gas sampling is done to characterize the chemical, thermal, or hydrological properties of a surface or subsurface hydrothermal system....

375

Water Sampling (Healy, 1970) | Open Energy Information  

Open Energy Info (EERE)

Water Sampling (Healy, 1970) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Water Sampling (Healy, 1970) Exploration Activity Details Location...

376

Water-Gas Sampling | Open Energy Information  

Open Energy Info (EERE)

Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon Water-Gas Sampling (Redirected from Water-Gas Samples) Redirect page Jump to: navigation,...

377

Grid Points (GridSampleSet)  

Science Conference Proceedings (OSTI)

... OOF2: The Manual. Grid Points (GridSampleSet). ... Name. Grid Points (GridSampleSet) — Evaluate data on a rectangular grid of points. Synopsis. ...

2013-08-23T23:59:59.000Z

378

Grid Points (StatGridSampleSet)  

Science Conference Proceedings (OSTI)

... OOF2: The Manual. Grid Points (StatGridSampleSet). ... Name. Grid Points (StatGridSampleSet) — Evaluate data on a rectangular grid of points. ...

2013-08-23T23:59:59.000Z

379

Water-Gas Sampling | Open Energy Information  

Open Energy Info (EERE)

Water-Gas Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Water-Gas Sampling edit Details Activities (21) Areas (18) Regions (1)...

380

Category:SamplePages | Open Energy Information  

Open Energy Info (EERE)

Category Edit History Facebook icon Twitter icon Category:SamplePages Jump to: navigation, search This category uses the form SampleForm. Note the pluralization. Category names...

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

ULTRAVIOLET PROPERTIES OF GALACTIC GLOBULAR CLUSTERS WITH GALEX. I. THE COLOR-MAGNITUDE DIAGRAMS  

SciTech Connect

We present Galaxy Evolution Explorer (GALEX) data for 44 Galactic globular clusters (GCs) obtained during three GALEX observing cycles between 2004 and 2008. This is the largest homogeneous data set on the UV photometric properties of Galactic GCs ever collected. The sample selection and photometric analysis are discussed, and color-magnitude diagrams (CMDs) are presented. The blue and intermediate-blue horizontal branch is the dominant feature of the UV CMDs of old Galactic GCs. Our sample is large enough to display the remarkable variety of horizontal branch shapes found in old stellar populations. Other stellar types that are obviously detected are blue stragglers and post-core-He burning stars. The main features of UV CMDs of Galactic GCs are briefly discussed. We establish the locus of post-core-He burning stars in the UV CMD and present a catalog of candidate asymptotic giant branch (AGB), AGB-manque, post early-AGB, and post-AGB stars within our cluster sample.

Schiavon, Ricardo P.; Rhee, Jaehyon [Gemini Observatory, 670 N. A'Ohoku Place, Hilo, HI 96720 (United States); Dalessandro, Emanuele; Ferraro, Francesco R.; Lanzoni, Barbara, E-mail: rschiavon@gemini.edu, E-mail: emanuele.dalessandr2@unibo.it, E-mail: francesco.ferraro3@unibo.it, E-mail: barbara.lanzoni@unibo.it [Dipartimento di Astronomia, Universita degli Studi di Bologna, via Ranzani 1, I-40127 Bologna (Italy); and others

2012-05-15T23:59:59.000Z

382

Using a new relational concept to improve the clustering performance of search engines  

Science Conference Proceedings (OSTI)

In this paper, we present a novel clustering algorithm to generate a number of candidate clusters from other web search results. The candidate clusters generate a connective relation among the clusters and the relation is semantic. Moreover, the algorithm ... Keywords: Document clustering, Relational concept, Semantic relation, Web documents, Web search engines

Lin-Chih Chen

2011-03-01T23:59:59.000Z

383

An effective density-based hierarchical clustering technique to identify coherent patterns from gene expression data  

Science Conference Proceedings (OSTI)

We present an effective tree-based clustering technique (Gene ClusTree) for finding clusters over gene expression data. GeneClusTree attempts to find all the clusters over subspaces using a tree-based density approach by scanning the whole database in ... Keywords: coherent patterns, maximal space cluster, p-value, reduced space cluster, z-score

Sauravjyoti Sarmah; Rosy Das Sarmah; Dhruba Kumar Bhattacharyya

2011-05-01T23:59:59.000Z

384

Data-Fusion in Clustering Microarray Data: Balancing Discovery and Interpretability  

Science Conference Proceedings (OSTI)

While clustering genes remains one of the most popular exploratory tools for expression data, it often results in a highly variable and biologically uninformative clusters. This paper explores a data fusion approach to clustering microarray data. Our ... Keywords: Clustering expression data, Gene Ontology, genomic data fusion, semantic similarity, cluster stability, knowledge-based validation.

Rafal Kustra; Adam Zagdanski

2010-01-01T23:59:59.000Z

385

Clustering based on a near neighbor graph and a grid cell graph  

Science Conference Proceedings (OSTI)

This paper presents two novel graph-clustering algorithms, Clustering based on a Near Neighbor Graph (CNNG) and Clustering based on a Grid Cell Graph (CGCG). CNNG algorithm inspired by the idea of near neighbors is an improved graph-clustering method ... Keywords: Clustering, Grid Cell Graph, Grid cell, Near Neighbor Graph, Near neighbor point set

Xinquan Chen

2013-06-01T23:59:59.000Z

386

An efficient cluster-based self-organisation algorithm for wireless sensor networks  

Science Conference Proceedings (OSTI)

The paper proposes an Efficient Cluster-based Self-organisation Algorithm (ECSA) for partitioning Wireless Sensor Networks (WSNs) into clusters, thus giving at the network a hierarchical organisation. Each sensor uses its weight ... Keywords: WSNs, cluster head, clustering algorithms, energy dissipation, homogeneous clusters, k-density, network lifetime, node weight, residual energy, self-organisation, wireless networks, wireless sensor networks

Mohamed Lehsaini; Herve Guyennet; Mohammed Feham

2010-02-01T23:59:59.000Z

387

Category:Field Sampling | Open Energy Information  

Open Energy Info (EERE)

Category Category Edit History Facebook icon Twitter icon » Category:Field Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Geothermalpower.jpg Looking for the Field Sampling page? For detailed information on Field Sampling as exploration techniques, click here. Category:Field Sampling Add.png Add a new Field Sampling Technique Subcategories This category has the following 2 subcategories, out of 2 total. G [×] Gas Sampling‎ 3 pages W [×] Water Sampling‎ 2 pages Pages in category "Field Sampling" The following 4 pages are in this category, out of 4 total. G Gas Sampling R Rock Sampling S Soil Sampling W Water Sampling Retrieved from "http://en.openei.org/w/index.php?title=Category:Field_Sampling&oldid=689818" Category: Field Techniques

388

The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: measurements of the growth of structure and expansion rate at z=0.57 from anisotropic clustering  

E-Print Network (OSTI)

We analyze the anisotropic clustering of massive galaxies from the Sloan Digital Sky Survey III Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 9 (DR9) sample, which consists of 264,283 galaxies in the redshift range 0.43 0.57, and when combined imply \\Omega_{\\Lambda} = 0.74 +/- 0.016, independent of the Universe's evolution at z<0.57. In our companion paper (Samushia et al. prep), we explore further cosmological implications of these observations.

Reid, Beth A; White, Martin; Percival, Will J; Manera, Marc; Padmanabhan, Nikhil; Ross, Ashley J; Sánchez, Ariel G; Bailey, Stephen; Bizyaev, Dmitry; Bolton, Adam S; Brewington, Howard; Brinkmann, J; Brownstein, Joel R; Cuesta, Antonio J; Eisenstein, Daniel J; Gunn, James E; Honscheid, Klaus; Malanushenko, Elena; Malanushenko, Viktor; Maraston, Claudia; McBride, Cameron K; Muna, Demitri; Nichol, Robert C; Oravetz, Daniel; Pan, Kaike; de Putter, Roland; Roe, N A; Ross, Nicholas P; Schlegel, David J; Schneider, Donald P; Seo, Hee-Jong; Shelden, Alaina; Sheldon, Erin S; Simmons, Audrey; Skibba, Ramin A; Snedden, Stephanie; Swanson, Molly E C; Thomas, Daniel; Tinker, Jeremy; Tojeiro, Rita; Verde, Licia; Wake, David A; Weaver, Benjamin A; Weinberg, David H; Zehavi, Idit; Zhao, Gong-Bo

2012-01-01T23:59:59.000Z

389

IS THE TWO MICRON ALL SKY SURVEY CLUSTERING DIPOLE CONVERGENT?  

Science Conference Proceedings (OSTI)

There is a long-standing controversy about the convergence of the dipole moment of the galaxy angular distribution (the so-called clustering dipole). Is the dipole convergent at all, and if so, what is the scale of the convergence? We study the growth of the clustering dipole of galaxies as a function of the limiting flux of the sample from the Two Micron All Sky Survey (2MASS). Contrary to some earlier claims, we find that the dipole does not converge before the completeness limit of the 2MASS Extended Source Catalog, i.e., up to 13.5 mag in the near-infrared K{sub s} band (equivalent to an effective distance of 300 Mpc h{sup -1}). We compare the observed growth of the dipole with the theoretically expected, conditional one (i.e., given the velocity of the Local Group relative to the cosmic microwave background), for the {Lambda}CDM power spectrum and cosmological parameters constrained by the Wilkinson Microwave Anisotropy Probe. The observed growth turns out to be within 1{sigma} confidence level of its theoretical counterpart once the proper observational window of the 2MASS flux-limited catalog is included. For a contrast, if the adopted window is a top hat, then the predicted dipole grows significantly faster and converges (within the errors) to its final value for a distance of about 300 Mpc h{sup -1}. By comparing the observational windows, we show that for a given flux limit and a corresponding distance limit, the 2MASS flux-weighted window passes less large-scale signal than the top-hat one. We conclude that the growth of the 2MASS dipole for effective distances greater than 200 Mpc h{sup -1} is only apparent. On the other hand, for a distance of 80 Mpc h{sup -1} (mean depth of the 2MASS Redshift Survey) and the {Lambda}CDM power spectrum, the true dipole is expected to reach only {approx}80% of its final value. Eventually, since for the window function of 2MASS the predicted growth is consistent with the observed one, we can compare the two to evaluate {beta} {identical_to} {Omega}{sub m}{sup 0.55}/b. The result is {beta} = 0.38 {+-} 0.04, which leads to an estimate of the density parameter {Omega}{sub m} = 0.20 {+-} 0.08.

Bilicki, Maciej; Chodorowski, Michal [Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, ul. Bartycka 18, 00-716, Warsaw (Poland); Jarrett, Thomas [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Mamon, Gary A., E-mail: bilicki@camk.edu.pl [Institut d'Astrophysique de Paris - UMR 7095 CNRS and UPMC, 98 bis Bd Arago, F-75014 Paris (France)

2011-11-01T23:59:59.000Z

390

Anion photoelectron spectroscopy of radicals and clusters  

SciTech Connect

Anion photoelectron spectroscopy is used to study free radicals and clusters. The low-lying {sup 2}{Sigma} and {sup 2}{Pi} states of C{sub 2n}H (n = 1--4) have been studied. The anion photoelectron spectra yielded electron affinities, term values, and vibrational frequencies for these combustion and astrophysically relevant species. Photoelectron angular distributions allowed the author to correctly assign the electronic symmetry of the ground and first excited states and to assess the degree of vibronic coupling in C{sub 2}H and C{sub 4}H. Other radicals studied include NCN and I{sub 3}. The author was able to observe the low-lying singlet and triplet states of NCN for the first time. Measurement of the electron affinity of I{sub 3} revealed that it has a bound ground state and attachment of an argon atom to this moiety enabled him to resolve the symmetric stretching progression.

Travis, Taylor R.

1999-12-16T23:59:59.000Z

391

Star count density profiles and structural parameters of 26 Galactic globular clusters  

E-Print Network (OSTI)

We used a proper combination of high-resolution HST observations and wide-field ground based data to derive the radial star density profile of 26 Galactic globular clusters from resolved star counts (which can be all freely downloaded on-line). With respect to surface brightness (SB) profiles (which can be biased by the presence of sparse, bright stars), star counts are considered to be the most robust and reliable tool to derive cluster structural parameters. For each system a detailed comparison with both King and Wilson models has been performed and the most relevant best-fit parameters have been obtained. This is the largest homogeneous catalog collected so far of star count profiles and structural parameters derived therefrom. The analysis of the data of our catalog has shown that: (1) the presence of the central cusps previously detected in the SB profiles of NGC 1851, M13 and M62 is not confirmed; (2) the majority of clusters in our sample are fitted equally well by the King and the Wilson models; (3) ...

Miocchi, P; Ferraro, F R; Dalessandro, E; Vesperini, E; Pasquato, M; Beccari, G; Pallanca, C; Sanna, N

2013-01-01T23:59:59.000Z

392

2011 Clusters, Nanocrystals & Nanostructures Gordon Research Conference  

DOE Green Energy (OSTI)

Small particles have been at the heart of nanoscience since the birth of the field and now stand ready to make significant contributions to the big challenges of energy, health and sustainability. Atomic clusters show exquisite size-dependent electronic and magnetic properties and offer a new level of control in catalyses, sensors and biochips; functionalised nanocrystals offer remarkable optical properties and diverse applications in electronic devices, solar energy, and therapy. Both areas are complemented by a raft of recent advances in fabrication, characterization, and performance of a diversity of nanomaterials from the single atom level to nanowires, nanodevices, and biologically-inspired nanosystems. The goal of the 2011 Gordon Conference is thus to continue and enhance the interdisciplinary tradition of this series and discuss the most recent advances, fundamental scientific questions, and emerging applications of clusters, nanocrystals, and nanostructures. A single conference covering all aspects of nanoscience from fundamental issues to applications has the potential to create new ideas and stimulate cross fertilization. The meeting will therefore provide a balance among the three sub-components of the conference, true to its title, with a selection of new topics added to reflect rapid advances in the field. The open atmosphere of a Gordon conference, emphasizing the presentation of unpublished results and extensive discussions, is an ideal home for this rapidly developing field and will allow all participants to enjoy a valuable and stimulating experience. Historically, this Gordon conference has been oversubscribed, so we encourage all interested researchers from academia, industry, and government institutions to apply as early as possible. We also encourage all attendees to submit their latest results for presentation at the poster sessions. We anticipate that several posters will be selected for 'hot topic' oral presentations. Given the important role students and postdocs play in the future of this field, we also anticipate several talks of this kind from young investigators.

Lai-Sheng Wang

2011-07-29T23:59:59.000Z

393

Electrphoretic Sample Excitation Light Assembly.  

DOE Patents (OSTI)

An automated electrophoretic system is disclosed. The system employs a capillary cartridge having a plurality of capillary tubes. The cartridge has a first array of capillary ends projecting from one side of a plate. The first array of capillary ends are spaced apart in substantially the same manner as the wells of a microtitre tray of standard size. This allows one to simultaneously perform capillary electrophoresis on samples present in each of the wells of the tray. The system includes a stacked, dual carrousel arrangement to eliminate cross-contamination resulting from reuse of the same buffer tray on consecutive executions from electrophoresis. The system also has a gel delivery module containing a gel syringe/a stepper motor or a high pressure chamber with a pump to quickly and uniformly deliver gel through the capillary tubes. The system further includes a multi-wavelength beam generator to generate a laser beam which produces a beam with a wide range of wavelengths. An off-line capillary reconditioner thoroughly cleans a capillary cartridge to enable simultaneous execution of electrophoresis with another capillary cartridge. The streamlined nature of the off-line capillary reconditioner offers the advantage of increased system throughput with a minimal increase in system cost.

Li, Qingbo (State College, PA); Liu, Changsheng (State College, PA)

2002-04-02T23:59:59.000Z

394

Sample storage/disposal study  

SciTech Connect

Radioactive waste from defense operations has accumulated at the Hanford Site`s underground waste tanks since the late 1940`s. Each tank must be analyzed to determine whether it presents any harm to the workers at the Hanford Site, the public or the environment. Analyses of the waste aids in the decision making process in preparation of future tank waste stabilization procedures. Characterization of the 177 waste tanks on the Hanford Site will produce a large amount of archived material. This also brings up concerns as to how the excess waste tank sample material from 325 and 222-S Analytical Laboratories will be handled. Methods to archive and/or dispose of the waste have been implemented into the 222-S and 325 Laboratory procedures. As the amount of waste characterized from laboratory analysis grows, an examination of whether the waste disposal system will be able to compensate for this increase in the amount of waste needs to be examined. Therefore, the need to find the safest, most economically sound method of waste storage/disposal is important.

Valenzuela, B.D.

1994-09-29T23:59:59.000Z

395

Exploiting hierarchical parallelisms for molecular dynamics simulation on multicore clusters  

Science Conference Proceedings (OSTI)

We have developed a scalable hierarchical parallelization scheme for molecular dynamics (MD) simulation on multicore clusters. The scheme explores multilevel parallelism combining: (1) Internode parallelism using spatial decomposition via message passing; ... Keywords: Molecular dynamics simulation, Multicore cluster, Scalable hierarchical parallelization scheme, Single instruction multiple data

Liu Peng; Manaschai Kunaseth; Hikmet Dursun; Ken-Ichi Nomura; Weiqiang Wang; Rajiv K. Kalia; Aiichiro Nakano; Priya Vashishta

2011-07-01T23:59:59.000Z

396

Opportunistic Scheduling in Multiuser OFDM Systems with Clustered Feedback  

Science Conference Proceedings (OSTI)

This paper proposes a random access based feedback protocol for multiuser orthogonal frequency division multiple access (OFDMA) systems with clustered feedback, where users are assigned to clusters of subcarriers based on the feedback of channel state ... Keywords: Limited feedback, OFDMA, Scheduling

Taiwen Tang; Chan-Byoung Chae; Robert W. Heath, Jr.; Sunghyun Cho; Sangboh Yun

2010-01-01T23:59:59.000Z

397

Query clustering using content words and user feedback  

Science Conference Proceedings (OSTI)

Query clustering is crucial for automatically discovering frequently asked queries (FAQs) or most popular topics on a question-answering search engine. Due to the short length of queries, the traditional approaches based on keywords are not suitable ... Keywords: log mining, query clustering, user feedback, web search

Ji-Rong Wen; Jian-Yun Nie; Hong-Jiang Zhang

2001-09-01T23:59:59.000Z

398

Vibrational and electronic properties of clusters and ultrathin films  

DOE Green Energy (OSTI)

This covers [approximately] 26 months of research. In addition to clusters and thin films, studies of bulk fullerene and amorphous carbon are also reported. Results and activities are reported under the headings: structure of C[sub 60], dynamics of C[sub 60], Raman scattering of fullerene-based systems, Bi clusters, and amorphous carbon structure.

Lannin, J.S.

1993-01-01T23:59:59.000Z

399

Ant colony clustering using mobile agents as ants and pheromone  

Science Conference Proceedings (OSTI)

This paper presents a new approach for controlling mobile multiple robots connected by communication networks. The control mechanism is based on a specific Ant Colony Clustering (ACC) algorithm. In traditional ACC, an ant convey an object, but in our ... Keywords: ant colony clustering, intelligent robot control, mobile agent

Masashi Mizutani; Munehiro Takimoto; Yasushi Kambayashi

2010-03-01T23:59:59.000Z

400

HUBBLE SPACE TELESCOPE PHOTOMETRY OF GLOBULAR CLUSTERS IN M81  

SciTech Connect

We perform aperture photometry and profile fitting on 419 globular cluster (GC) candidates with m{sub V} {<=} 23 mag identified in Hubble Space Telescope/Advanced Camera for Surveys BVI imaging, and estimate the effective radii of the clusters. We identify 85 previously known spectroscopically confirmed clusters, and newly identify 136 objects as good cluster candidates within the 3{sigma} color and size ranges defined by the spectroscopically confirmed clusters, yielding a total of 221 probable GCs. The luminosity function peak for the 221 probable GCs with estimated total dereddening applied is V {approx} (20.26 {+-} 0.13) mag, corresponding to a distance of {approx}3.7 {+-} 0.3 Mpc. The blue and red GC candidates, and the metal-rich and metal-poor spectroscopically confirmed clusters, respectively, are similar in half-light radius. Red confirmed clusters are about 6% larger in median half-light radius than blue confirmed clusters, and red and blue good GC candidates are nearly identical in half-light radius. The total population of confirmed and 'good' candidates shows an increase in half-light radius as a function of galactocentric distance.

Nantais, Julie B. [Departamento de Astronomia, Universidad de Concepcion Av. Esteban Iturra s/n Barrio Universitario Casilla 160-C Concepcion (Chile); Huchra, John P.; Zezas, Andreas; Gazeas, Kosmas; Strader, Jay [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2011-12-15T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Panache: a parallel WAN cache for clustered filesystems  

Science Conference Proceedings (OSTI)

Panache is a scalable, high-performance, remote file data caching solution integrated with the GPFS cluster file system. It leverages the inherent scalability of GPFS to provide a multi-node, consistent cache of data exported by a remote file system ... Keywords: caching, cluster filesystem, pNFS, wide-area network

R. Ananthanarayanan; M. Eshel; R. Haskin; M. Naik; F. Schmuck; R. Tewari

2008-01-01T23:59:59.000Z

402

Review: Clustering of high throughput gene expression data  

Science Conference Proceedings (OSTI)

High throughput biological data need to be processed, analyzed, and interpreted to address problems in life sciences. Bioinformatics, computational biology, and systems biology deal with biological problems using computational methods. Clustering is ... Keywords: Bioinformatics, Clustering, Gene expression data, High throughput data, Microarrays

Harun Pirim; Burak Ek?Io?Lu; Andy D. Perkins; ÇEtin YüCeer

2012-12-01T23:59:59.000Z

403

Surveillance to detect emerging space-time clusters  

Science Conference Proceedings (OSTI)

The interest is on monitoring incoming space-time events to detect an emergent space-time cluster as early as possible. Assume that point process events are continuously recorded in space and time. In a certain unknown moment, a small localized cluster ...

Renato Assunção; Thais Correa

2009-06-01T23:59:59.000Z

404

Competitive Clustering in a Bi-disperse Granular Gas  

E-Print Network (OSTI)

A bi-disperse granular gas in a compartmentalized system is experimentally found to cluster competitively: Depending on the shaking strength, the clustering can be directed either towards the compartment initially containing mainly small particles, or to the one containing mainly large particles. The experimental observations are quantitatively explained within a flux model.

René Mikkelsen; Devaraj van der Meer; Ko van der Weele; Detlef Lohse

2002-10-06T23:59:59.000Z

405

Fuzzy Logic-based Mobility Metric Clustering Algorithm for MANETs  

Science Conference Proceedings (OSTI)

Mobile ad-hoc network, MANET is a collection of wireless mobile nodes dynamically forming a temporary communication network without using any existing infrastructure or centralized administration. To reduce routing overhead, computational complexity ... Keywords: Cluster, Fuzzy Clustering, Fuzzy Logic, MANET, Mobility Metric

P. Venkateswaran; Mousumi Kundu; Srishti Shaw; Kanika Orea; R. Nandi

2011-07-01T23:59:59.000Z

406

Virtual InfiniBand clusters for HPC clouds  

Science Conference Proceedings (OSTI)

High Performance Computing (HPC) employs fast interconnect technologies to provide low communication and synchronization latencies for tightly coupled parallel compute jobs. Contemporary HPC clusters have a fixed capacity and static runtime environments; ... Keywords: HPC, InfiniBand, cloud computing, cluster, virtualization

Marius Hillenbrand; Viktor Mauch; Jan Stoess; Konrad Miller; Frank Bellosa

2012-04-01T23:59:59.000Z

407

BARC: A Battery Aware Reliable Clustering algorithm for sensor networks  

Science Conference Proceedings (OSTI)

Clustering in wireless sensor networks (WSNs) provides scalability and robustness for the network; it allows spatial reuse of the bandwidth, simpler routing decisions, and results in decreased energy dissipation of the whole system by minimizing the ... Keywords: Battery awareness, Clustering, Hierarchical, Load balancing, Sensor networks

Mohamed K. Watfa; Omar Mirza; Jad Kawtharani

2009-11-01T23:59:59.000Z

408

A Spitzer search for cold dust within globular clusters  

E-Print Network (OSTI)

Globular cluster stars evolving off the main sequence are known to lose mass, and it is expected that some of the lost material should remain within the cluster as an intracluster medium (ICM). Most attempts to detect such an ICM have been unsuccessful. The Multiband Imaging Photometer for Spitzer on the Spitzer Space Telescope was used to observe eight Galactic globular clusters in an attempt to detect the thermal emission from ICM dust. Most clusters do not have significant detections at 70 microns; one cluster, NGC 6341, has tentative evidence for the presence of dust, but 90 micron observations do not confirm the detection. Individual 70 micron point sources which appear in several of the cluster images are likely to be background galaxies. The inferred dust mass and upper limits are solar masses, well below expectations for cluster dust production from mass loss in red and asymptotic giant branch stars. This implies that either globular cluster dust production is less efficient, or that ICM rem...

Barmby, P; Woodward, C E; Gehrz, R D; van Loon, J Th; Fazio, G G; Marengo, M; Polomski, E

2008-01-01T23:59:59.000Z

409

Electronic poster: eeclust: energy-efficient cluster computing  

Science Conference Proceedings (OSTI)

The eeClust project aims at reducing the energy consumption of applications on a HPC cluster by an integrated approach of analysis, efficient management of hardware power-states and monitoring of the clusters power consumption. The application is traced ... Keywords: analysis, benchmark, energy, monitoring, power

Michael Knobloch; Timo Minartz; Daniel Molka; Stephan Krempel; Thomas Ludwig; Bernd Mohr

2011-11-01T23:59:59.000Z

410

Using `core documents' for the representation of clusters and topics  

Science Conference Proceedings (OSTI)

The notion of `core documents', first introduced in the context of co-citation analysis and later re-introduced for bibliographic coupling, refers to the representation of the core of a publication set according to given criteria. In the present study, ... Keywords: Bibliographic coupling, Cluster analysis, Core documents, Hybrid clustering, Text mining

Wolfgang Glänzel; Bart Thijs

2011-07-01T23:59:59.000Z

411

Hierarchical clustering using correlation metric and spatial continuity constraint  

DOE Patents (OSTI)

Large data sets are analyzed by hierarchical clustering using correlation as a similarity measure. This provides results that are superior to those obtained using a Euclidean distance similarity measure. A spatial continuity constraint may be applied in hierarchical clustering analysis of images.

Stork, Christopher L.; Brewer, Luke N.

2012-10-02T23:59:59.000Z

412

An HI Threshold for Star Cluster Formation in Tidal Debris  

E-Print Network (OSTI)

Super star clusters are young, compact star clusters found in the central regions of interacting galaxies. Recently, they have also been reported to preferentially form in certain tidal tails, but not in others. In this paper, we have used 21 cm HI maps and the Hubble Space Telescope Wide Field Planetary Camera 2 images of eight tidal tail regions of four merging galaxy pairs to compare the kiloparsec scale HI distribution with the location of super star clusters found from the optical images. For most of the tails, we find that there is an increase in super star cluster density with increasing projected HI column density, such that the star cluster density is highest when log N(HI) >= 20.6 cm^{-2}, but equal to the background count rate at lower HI column density. However, for two tails (NGC 4038/39 Pos A and NGC 3921), there is no significant star cluster population despite the presence of gas at high column density. This implies that the N(HI) threshold is a necessary but not sufficient condition for cluster formation. Gas volume density is likely to provide a more direct criterion for cluster formation, and other factors such as gas pressure or strength of encounter may also have an influence. Comparison of HI thresholds needed for formation of different types of stellar structures await higher resolution HI and optical observations of larger numbers of interacting galaxies.

A. Maybhate; J. Masiero; J. E. Hibbard; J. C. Charlton; C. Palma; K. A. Knierman; J. English

2007-07-24T23:59:59.000Z

413

Minimizing Remote Accesses in MapReduce Clusters  

Science Conference Proceedings (OSTI)

MapReduce, in particular Hadoop, is a popular framework for the distributed processing of large datasets on clusters of relatively inexpensive servers. Although Hadoop clusters are highly scalable and ensure data availability in the face of server failures, ... Keywords: MapReduce, Hadoop, remote accesses, data placement

Prateek Tandon, Michael J. Cafarella, Thomas F. Wenisch

2013-05-01T23:59:59.000Z

414

Topology-aware tile mapping for clusters of SMPs  

Science Conference Proceedings (OSTI)

We propose a technique to optimize the performance of applications using distributed dense arrays and characterized by a nearest-neighbor communication profile by exploiting the topology of SMP clusters. The topological information is used to map array ... Keywords: clusters of SMPs, communication optimization, data layout optimization, topology awareness

Daniel Chavarría-Miranda; Jarek Nieplocha; Vinod Tipparaju

2006-05-01T23:59:59.000Z

415

Cluster based dynamic routing on powerline carrier network  

Science Conference Proceedings (OSTI)

Topology of power line carrier network (PLCN) is complex, fast changeable and its channel is time-variant. To enhance the availability and effectiveness of network communication, a cluster based dynamic routing algorithm (CBDR) is proposed in the paper. ... Keywords: cluster algorithm, dynamic route, powerline carrier network, tree-topology

Hong Li; Wang Kensheng; Li Shurong; Zou Weixia; Zhou Zheng

2009-09-01T23:59:59.000Z

416

SPC: The Selective Prioritized Clustering Algorithm for MANETs  

Science Conference Proceedings (OSTI)

Energy conservation is the major issue of concern for MANETs [1], [2] as terminals are battery operated. We propose an algorithm called selective prioritized clustering (SPC), to reduce power consumption at network level. It uses topology control and ... Keywords: Energy consumption, clustering, global and local path, topology control, Ad hoc network

T. Vijeesh; Niranjan Kumar Ray; Ashok Kumar Turuk

2010-12-01T23:59:59.000Z

417

Coscheduling in Clusters: Is It a Viable Alternative?  

Science Conference Proceedings (OSTI)

In this paper, we conduct an in-depth evaluation of a broad spectrum of scheduling alternatives for clusters. These include the widely used batch scheduling, local scheduling, gang scheduling, all prior communication-driven coscheduling algorithms (Dynamic ... Keywords: Experimentation, Performance Measurement, Scheduling, Coscheduling, Linux Cluster, Myrinet, Batch Scheduling, Gang Scheduling, Energy Consumption

Gyu Sang Choi; Jin-Ha Kim; Deniz Ersoz; Andy B. Yoo; Chita R. Das

2004-11-01T23:59:59.000Z

418

Identifying Objects in Procedural Programs Using Clustering Neural Networks  

Science Conference Proceedings (OSTI)

This paper presents a general approach for the identification of objects in procedural programs. The approach is based on neural architectures that perform an unsupervised learning of clusters. We describe two such neural architectures, explain how to ... Keywords: abstract data types, clustering, neural networks, objects

Salwa K. Abd-El-Hafiz

2000-07-01T23:59:59.000Z

419

ABUNDANCES OF RED GIANTS IN OLD OPEN CLUSTERS. V. Be 31, Be 32, Be 39, M 67, NGC 188, AND NGC 1193  

SciTech Connect

We present a detailed abundance analysis based on high resolution spectroscopy for 16 stars in the old open clusters Be 31, Be 32, Be 39, M 67, NGC 188, and NGC 1193. Average cluster metallicities of [Fe/H] = -0.30 {+-} 0.02, -0.21 {+-} 0.01, +0.03 {+-} 0.07, +0.12 {+-} 0.02, and -0.22 {+-} 0.14 (s.d.) have been found for Be 32, Be 39, M 67, NGC 188, and NGC 1193, respectively. The two stars observed in the field of Be 31 have disparate radial velocities and elemental abundance patterns, and also disagree with the possible Be 31 star studied by Yong et al. We conclude that membership has yet to be established for this important cluster, and therefore no element abundances measured here or in previous studies of Be 31 should be taken as definitive cluster abundances. A careful comparison of our results for the clusters M 67 and Be 32 to those of other studies shows general good agreement and identifies systematic differences resulting from different analyses. After combination of our results with those of other studies for clusters spanning the full R{sub gc} range of the thin disk, we explore the abundance distributions as a function of R{sub gc} and age for the elements Fe, O, Na, Mg, Al, Si, Ca, Ti, and Ni. As found in previous work, the [Fe/H] gradient appears to be continuous up to R{sub gc} {approx} 13 kpc before flattening in the outer disk. [X/Fe] ratios show a scatter of 0.2-0.3 dex at all R{sub gc}, for all elements considered. The [X/Fe] values of the six clusters analyzed here are consistent with those of other clusters of similar metallicity and Galactocentric location. Our whole cluster sample shows trends of increasing [O/Fe] and [Al/Fe] with age, although these trends vanish with the inclusion of other clusters from the literature. Larger, homogeneous open cluster samples are necessary to verify the existence and magnitude of abundance trends with age.

Friel, Eileen D. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Jacobson, Heather R. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48823 (United States); Pilachowski, Catherine A., E-mail: friel@lowell.ed, E-mail: jacob189@msu.ed, E-mail: catyp@astro.indiana.ed [Department of Astronomy, Indiana University, Bloomington, IN 47405 (United States)

2010-05-15T23:59:59.000Z

420

Symbolic-numerical Algorithm for Generating Cluster Eigenfunctions: Tunneling of Clusters Through Repulsive Barriers  

E-Print Network (OSTI)

A model for quantum tunnelling of a cluster comprising A identical particles, coupled by oscillator-type potential, through short-range repulsive potential barriers is introduced for the first time in the new symmetrized-coordinate representation and studied within the s-wave approximation. The symbolic-numerical algorithms for calculating the effective potentials of the close-coupling equations in terms of the cluster wave functions and the energy of the barrier quasistationary states are formulated and implemented using the Maple computer algebra system. The effect of quantum transparency, manifesting itself in nonmonotonic resonance-type dependence of the transmission coefficient upon the energy of the particles, the number of the particles A=2,3,4, and their symmetry type, is analyzed. It is shown that the resonance behavior of the total transmission coefficient is due to the existence of barrier quasistationary states imbedded in the continuum.

Vinitsky, Sergue; Chuluunbaatar, Ochbadrakh; Rostovtsev, Vitaly; Hai, Luong Le; Derbov, Vladimir; Krassovitskiy, Pavel

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Multi-class blue noise sampling  

Science Conference Proceedings (OSTI)

Sampling is a core process for a variety of graphics applications. Among existing sampling methods, blue noise sampling remains popular thanks to its spatial uniformity and absence of aliasing artifacts. However, research so far has been mainly focused ... Keywords: blue noise, dart throwing, multi-class, poisson hard/soft disk, relaxation, sampling

Li-Yi Wei

2010-07-01T23:59:59.000Z

422

Reduce, reuse, recycle for robust cluster-state generation  

SciTech Connect

Efficient generation of cluster states is crucial for engineering large-scale measurement-based quantum computers. Hybrid matter-optical systems offer a robust, scalable path to this goal. Such systems have an ancilla which acts as a bus connecting the qubits. We show that by generating the cluster in smaller sections of interlocking bricks, reusing one ancilla per brick, the cluster can be produced with maximal efficiency, requiring fewer than half the operations compared with no bus reuse. By reducing the time required to prepare sections of the cluster, bus reuse more than doubles the size of the computational workspace that can be used before decoherence effects dominate. A row of buses in parallel provides fully scalable cluster-state generation requiring only 20 controlled-phase gates per bus use.

Horsman, Clare [Department of Mathematics, University of Bristol, University Walk, Bristol BS8 1TW (United Kingdom); H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL (United Kingdom); Brown, Katherine L.; Kendon, Vivien M. [School of Physics and Astronomy, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT (United Kingdom); Munro, William J. [National Institute of Informatics, 2-1-2 Hitotsubashi, Chiyoda ku, Tokyo 101-8430 (Japan); NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi-shi, Kanagawa 243-0198 (Japan)

2011-04-15T23:59:59.000Z

423

Predicting Merger-Induced Gas Motions in LCDM Galaxy Clusters  

E-Print Network (OSTI)

In the hierarchical structure formation model, clusters of galaxies form through a sequence of mergers and continuous mass accretion, which generate significant random gas motions especially in their outskirts where material is actively accreting. Non-thermal pressure provided by the internal gas motions affects the thermodynamic structure of the X-ray emitting intracluster plasma and introduces biases in the physical interpretation of X-ray and Sunyaev-Zeldovich effect observations. However, we know very little about the nature of gas motions in galaxy clusters. The ASTRO-H X-ray mission, scheduled to launch in 2015, will have a calorimeter capable of measuring gas motions in galaxy clusters at the level of gas motions expected in the LCDM model using hydrodynamical simulations of galaxy cluster formation, focusing on the merger-induced gas motions. We show that the gas velocity dispersion is larger in more massive clusters, but exhibits large ...

Nagai, Daisuke; Avestruz, Camille; Nelson, Kaylea; Rudd, Douglas H

2013-01-01T23:59:59.000Z

424

Nuclear Star Clusters in Edge-on Galaxies  

E-Print Network (OSTI)

From observations of edge-on, late-type galaxies, we present morphological evidence that some nuclear star clusters have experienced in situ star formation. We find three nuclear clusters that, viewed from the edge-on perspective, have both a compact disk-like component and a spheroidal component. In each cluster, the disk components are closely aligned with the major axis of the host galaxy and have bluer colors than the spheroidal components. We spectroscopically verify that one of the observed multiple component clusters has multiple generations of stars. These observations lead us to suggest a formation mechanism for nuclear star clusters, in which stars episodically form in compact nuclear disks, and then lose angular momentum, eventually forming an older spheroid.

Anil C. Seth; Julianne J. Dalcanton; Paul W. Hodge; Victor P. Debattista

2006-06-02T23:59:59.000Z

425

Low work function, stable compound clusters and generation process  

DOE Patents (OSTI)

Low work function, stable compound clusters are generated by co-evaporation of a solid semiconductor (i.e., Si) and alkali metal (i.e., Cs) elements in an oxygen environment. The compound clusters are easily patterned during deposition on substrate surfaces using a conventional photo-resist technique. The cluster size distribution is narrow, with a peak range of angstroms to nanometers depending on the oxygen pressure and the Si source temperature. Tests have shown that compound clusters when deposited on a carbon substrate contain the desired low work function property and are stable up to 600.degree. C. Using the patterned cluster containing plate as a cathode baseplate and a faceplate covered with phosphor as an anode, one can apply a positive bias to the faceplate to easily extract electrons and obtain illumination.

Dinh, Long N. (Concord, CA); Balooch, Mehdi (Berkeley, CA); Schildbach, Marcus A. (Livermore, CA); Hamza, Alex V. (Livermore, CA); McLean, II, William (Oakland, CA)

2000-01-01T23:59:59.000Z

426

Asymmetric explosion of clusters in intense laser fields  

Science Conference Proceedings (OSTI)

We examine asymmetric expansion of argon clusters illuminated by 800 nm laser pulses of duration Almost-Equal-To 23fs, using three-dimensional particle-in-cell (PIC) simulation. For this short pulse duration, laser energy absorption by cluster electrons is dominated by the nonlinear resonance (NLR) absorption process [Phys. Rev. Lett. 96, 123401 (2006)]. In this work, we concentrate, particularly, on the ionic outcome in the NLR regime and show that higher charge states of argon ions are produced along the laser polarization than in the transverse directions leading to the anisotropy (asymmetry) in the ion energy distribution. This anisotropy already established during the short pulse duration (or in the early duration of a long pulse) may contribute to the anisotropic ion emission reported in cluster experiments with pulse duration longer than 100 fs. Our PIC results are compared with a charged-sphere model showing that cluster explosion is mainly due to Coulomb repulsion between the cluster ions.

Kundu, M. [Institute for Plasma Research, Bhat, Gandhinagar 382 428, Gujarat (India)

2012-08-15T23:59:59.000Z

427

Nuclear Star Clusters in Edge-on Galaxies  

E-Print Network (OSTI)

From observations of edge-on, late-type galaxies, we present morphological evidence that some nuclear star clusters have experienced in situ star formation. We find three nuclear clusters that, viewed from the edge-on perspective, have both a compact disk-like component and a spheroidal component. In each cluster, the disk components are closely aligned with the major axis of the host galaxy and have bluer colors than the spheroidal components. We spectroscopically verify that one of the observed multiple component clusters has multiple generations of stars. These observations lead us to suggest a formation mechanism for nuclear star clusters, in which stars episodically form in compact nuclear disks, and then lose angular momentum, eventually forming an older spheroid. The full results of this study can be found in a forthcoming paper. 1

Anil C. Seth; Julianne J. Dalcanton; Paul W. Hodge; Victor P

2006-01-01T23:59:59.000Z

428

Soil Gas Sampling | Open Energy Information  

Open Energy Info (EERE)

Soil Gas Sampling Soil Gas Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Soil Gas Sampling Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Field Sampling Parent Exploration Technique: Gas Sampling Information Provided by Technique Lithology: Stratigraphic/Structural: Identify concealed faults that act as conduits for hydrothermal fluids. Hydrological: Identify hydrothermal gases of magmatic origin. Thermal: Differentiate between amagmatic or magmatic sources heat. Dictionary.png Soil Gas Sampling: Soil gas sampling is sometimes used in exploration for blind geothermal resources to detect anomalously high concentrations of hydrothermal gases

429

Gas Flux Sampling | Open Energy Information  

Open Energy Info (EERE)

Gas Flux Sampling Gas Flux Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Gas Flux Sampling Details Activities (26) Areas (20) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Field Sampling Parent Exploration Technique: Gas Sampling Information Provided by Technique Lithology: Stratigraphic/Structural: High flux can be indicative of conduits for fluid flow. Hydrological: Thermal: Anomalous flux is associated with active hydrothermal activity. Dictionary.png Gas Flux Sampling: Gas flux sampling measures the flow of volatile gas emissions from a specific location and compares it to average background emissions. Anomalously high gas flux can be an indication of hydrothermal activity.

430

Surface Gas Sampling | Open Energy Information  

Open Energy Info (EERE)

Surface Gas Sampling Surface Gas Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Surface Gas Sampling Details Activities (12) Areas (10) Regions (1) NEPA(0) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Field Sampling Parent Exploration Technique: Gas Sampling Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Gas composition and source of fluids. Thermal: Distinguish magmatic/mantle heat inputs. Can be used to estimate reservoir fluid temperatures. Dictionary.png Surface Gas Sampling: Gas sampling is done to characterize the chemical, thermal, or hydrological properties of a surface or subsurface hydrothermal system. Other definitions:Wikipedia Reegle Introduction

431

NIST_1A 1024 sample_count -i 57202424 sample_n_bytes -i ...  

Science Conference Proceedings (OSTI)

NIST_1A 1024 sample_count -i 57202424 sample_n_bytes -i 2 channel_count -i 1 sample_byte_format -s2 01 sample_rate -i 16000 ...

2004-03-08T23:59:59.000Z

432

Sample introduction apparatus for a flow cytometer  

DOE Patents (OSTI)

A sample introduction system for a flow cytometer allows easy change of sample containers such as test tubes and facilitates use in high pressure environments. The sample container includes a cap having a pressure supply chamber and a sample container attachment cavity. A sample container may be automatically positioned into the attachment cavity so as to sealably engage the end of the sample container as its outer surface. This positioning may be accomplished through some sample introduction mechanism. To facilitate cleaning HPLC tubing and fittings may be used in a manner which facilitates removable of the entire tubing from both the nozzle container and other sample container cap to permit its replacement to avoid contamination. The sample container support may include horizontal stops which loosely limit the movement of the sample container and thus avoid further stresses upon it.

Van den Engh, Ger (Seattle, WA)

1998-01-01T23:59:59.000Z

433

Sample introduction system for a flow cytometer  

SciTech Connect

A sample introduction system for a flow cytometer allows easy change of sample containers such as test tubes and facilitates use in high pressure environments. The sample container includes a cap having a pressure supply chamber and a sample container attachment cavity. A sample container may be automatically positioned into the attachment cavity so as to sealably engage the end of the sample container as its outer surface. This positioning may be accomplished through some sample introduction mechanism. To facilitate cleaning, HPLC tubing and fittings may be used in a manner which facilitates removing of the entire tubing from both the nozzle container and other sample container cap to permit its replacement to avoid contamination. The sample container support may include horizontal stops which loosely limit the movement of the sample container and thus avoid further stresses upon it.

Van den Engh, Ger (Seattle, WA)

1997-01-01T23:59:59.000Z

434

Sample introduction system for a flow cytometer  

DOE Patents (OSTI)

A sample introduction system for a flow cytometer allows easy change of sample containers such as test tubes and facilitates use in high pressure environments. The sample container includes a cap having a pressure supply chamber and a sample container attachment cavity. A sample container may be automatically positioned into the attachment cavity so as to sealably engage the end of the sample container as its outer surface. This positioning may be accomplished through some sample introduction mechanism. To facilitate cleaning, HPLC tubing and fittings may be used in a manner which facilitates removing of the entire tubing from both the nozzle container and other sample container cap to permit its replacement to avoid contamination. The sample container support may include horizontal stops which loosely limit the movement of the sample container and thus avoid further stresses upon it. 3 figs.

Engh, G. van den

1997-02-11T23:59:59.000Z

435

Sample introduction apparatus for a flow cytometer  

DOE Patents (OSTI)

A sample introduction system for a flow cytometer allows easy change of sample containers such as test tubes and facilitates use in high pressure environments. The sample container includes a cap having a pressure supply chamber and a sample container attachment cavity. A sample container may be automatically positioned into the attachment cavity so as to sealably engage the end of the sample container as its outer surface. This positioning may be accomplished through some sample introduction mechanism. To facilitate cleaning HPLC tubing and fittings may be used in a manner which facilitates removable of the entire tubing from both the nozzle container and other sample container cap to permit its replacement to avoid contamination. The sample container support may include horizontal stops which loosely limit the movement of the sample container and thus avoid further stresses upon it. 3 figs.

Van den Engh, G.

1998-03-10T23:59:59.000Z

436

COMPLETION REPORT FOR WELL CLUSTER ER-5-3  

SciTech Connect

Well Cluster ER-5-3 was drilled for the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office in support of the Nevada Environmental Restoration Project at the Nevada Test Site, Nye County, Nevada. This cluster of 3 wells was drilled in 2000 and 2001 as part of a hydrogeologic investigation program in Frenchman Flat. The first borehole in the cluster, Well ER-5-3, was drilled in February and March 2000. A 47.0-centimeter surface hole was drilled and cased off to the depth of 374.8 meters. The hole diameter was decreased to 31.1 centimeters for drilling to a total depth of 794.3 meters within welded ash-flow tuff. A piezometer string with 1 slotted interval was installed in the annulus of the surface casing, open to the saturated alluvium. A completion string with 2 slotted intervals was installed in the main hole, open to saturated alluvium and to the welded tuff aquifer. A second piezometer string with 1 slotted interval open to the welded-tuff aquifer was installed outside the completion string. Well ER-5-3 No.2 was drilled about 30 meters west of the first borehole in March 2000, and was recompleted in March 2001. A 66.0-centimeter hole was drilled and cased off to the depth of 613.8 meters. The hole diameter was decreased to 44.5 centimeters and the borehole was drilled and cased off to the depth of 849.0 meters. The hole diameter was decreased once more to 31.1 centimeters for drilling to a total depth of 1,732.2 meters in dolomite. A completion string open to the dolomite (lower carbonate aquifer) was installed. Well ER-5-3 No.3 was drilled approximately 30 meters north of the first 2 boreholes in February 2001. A 66.0-centimeter hole was drilled and cased off to the depth of 36.6 meters, then the main 25.1-centimeter-diameter hole was drilled to a total depth of 548.6 meters in alluvium. A slotted stainless-steel tubing string was installed in the saturated alluvium. A preliminary composite, static water level was measured at the depth of 282.6 meters, prior to development and hydrologic testing. Detailed lithologic descriptions and stratigraphic assignments are included in the report. These are based on composite drill cuttings collected every 3 meters, and 120 sidewall samples taken at various depths below 91 meters in Wells ER-5-3 and ER-5-3 No.2, supplemented by geophysical log data. The wells penetrated Quaternary/Tertiary alluvium to the depth of 622.4 meters, and an 8.5-meter-thick basalt flow was encountered within the alluvium. Tertiary tuff was penetrated to the depth of approximately 1,425.9 meters, where the top of the lower carbonate aquifer was tagged in Well ER-5-3 No.2.

BECHTEL NEVADA

2005-12-01T23:59:59.000Z

437

Nano-Domain Analysis Via Massive Cluster Secondary Ion Mass Spectrometry in the Event-by-Event Mode  

E-Print Network (OSTI)

Secondary ion mass spectrometry (SIMS) is a surface analysis technique which characterizes species sputtered by an energetic particle beam. Bombardment with cluster projectiles offers the following notable advantages over bombardment with atomic ions or small clusters: enhanced emission of molecular ions, low damage cross-section, and reduced molecular fragmentation. Additionally, in the case of Au4004 and C60 impacts, desorption originates from nanometric volumes. These features make clusters useful probes to obtain molecular information from both nano-objects and nano-domains. The "event-by-event bombardment/detection mode" probes nano-objects one-at-a-time, while collecting and storing the corresponding secondary ion (SI) information. Presented here are the first experiments where free-standing nano-objects were bombarded with keV projectiles of atomic to nanoparticle size. The objects are aluminum nano-whiskers, 2 nm in diameter and ~250 nm in length. Au4004 has a diameter of ~2 nm, comparable to the nominal diameter of the nanowhiskers. There are notable differences in the SI response from sample volumes too small for full projectile energy deposition. The whisker spectra are dominated by small clusters?the most abundant species being AlO- and AlO2-. Bulk samples have larger yields for AlO2- than for AlO-, while this trend is reversed in whisker samples. Bulk samples give similar abundances of large SI clusters, while whisker samples give an order of magnitude lower yield of these SIs. Effective yields were calculated in order to determine quantitative differences between the nano-objects and bulk samples. The characterization of individual nano-objects from a mixture is demonstrated with negatively charged polymer spheres that are attracted to and retained by the nano-whiskers. The spheres are monodisperse polystyrene nanoparticles (30nm diameter). Our results show that the event-by-event mode can provide information on the nature, size, relative location, and abundance of nano-objects in the field of view. This study presents the first evidence of quantitative molecular information originating from nano-object mixtures. Biologically relevant systems (solid-supported lipid bilayers) were also characterized using Au5 , Au4004 and C60 . Organization-dependent SI emission was observed for phosphocholine bilayers. Lipid domain formation was also investigated in bilayers formed from cholesterol and a mixed lipid system. Trends in the correlation coefficient suggest that cholesterol segregates from the surrounding lipid environment during raft formation.

Pinnick, Veronica Tiffany

2009-12-01T23:59:59.000Z

438

An enhanced clustering algorithm for mobile ad hoc networks to improve the throughput  

Science Conference Proceedings (OSTI)

Mobile ad hoc networks (MANETs) consist of a number of wireless hosts that forms network without a fixed infrastructure. Clustering plays a vital role for MANETs in managing the resources. Clustering involves two processes such as cluster head ...

S. Muthuramalingam; R. Rajaram

2011-09-01T23:59:59.000Z

439

A COMPREHENSIVE GALEX ULTRAVIOLET CATALOG OF STAR CLUSTERS IN M31 AND A STUDY OF THE YOUNG CLUSTERS  

Science Conference Proceedings (OSTI)

We present a comprehensive catalog of 700 confirmed star clusters in the field of M31 compiled from three major existing catalogs. We detect 418 and 257 star clusters in Galaxy Evolution Explorer near-ultraviolet and far-ultraviolet (FUV) imaging, respectively. Our final catalog includes photometry of star clusters in up to 16 passbands ranging from FUV to NIR as well as ancillary information such as reddening, metallicity, and radial velocities. In particular, this is the most extensive and updated catalog of UV-integrated photometry for M31 star clusters. Ages and masses of star clusters are derived by fitting the multi-band photometry with model spectral energy distribution (SED); UV photometry enables more accurate age estimation of young clusters. Our catalog includes 182 young clusters with ages less than 1 Gyr. Our estimated ages and masses of young clusters are in good agreement with previously determined values in the literature. The mean age and mass of young clusters are about 300 Myr and 10{sup 4} M{sub Sun }, respectively. We found that the compiled [Fe/H] values of young clusters included in our catalog are systematically lower (by more than 1 dex) than those from recent high-quality spectroscopic data and our SED-fitting result. We confirm that most of the young clusters' kinematics shows systematic rotation around the minor axis and association with the thin disk of M31. The young cluster distribution exhibits a distinct peak in the M31 disk around 10-12 kpc from the center and follows a spatial distributions similar to other tracers of disk structure such as OB stars, UV star-forming regions, and dust. Some young clusters also show concentration around the ring splitting regions found in the southern part of the M31 disk and most of them have systematically younger (star formation ring structure in the M31 disk. Consequently, we suggest that various properties of young clusters in M31 might be in line with the scenarios that a satellite galaxy had passed through the disk of M31 less than few hundred million years ago.

Kang, Yongbeom; Rey, Soo-Chang; Lee, Kyungsook; Kim, YoungKwang [Department of Astronomy and Space Science, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Bianchi, Luciana [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Sohn, Sangmo Tony, E-mail: ybkang@cnu.ac.kr, E-mail: screy@cnu.ac.kr [Space Telescope Science Institute, Baltimore, MD 21218 (United States)

2012-04-01T23:59:59.000Z

440

WAS THE SUN BORN IN A MASSIVE CLUSTER?  

Science Conference Proceedings (OSTI)

A number of authors have argued that the Sun must have been born in a cluster of no more than several thousand stars, on the basis that, in a larger cluster, close encounters between the Sun and other stars would have truncated the outer solar system or excited the outer planets into eccentric orbits. However, this dynamical limit is in tension with meteoritic evidence that the solar system was exposed to a nearby supernova during or shortly after its formation; a several-thousand-star cluster is much too small to produce a massive star whose lifetime is short enough to have provided the enrichment. In this paper, we revisit the dynamical limit in the light of improved observations of the properties of young clusters. We use a series of scattering simulations to measure the velocity-dependent cross-section for disruption of the outer solar system by stellar encounters, and use this cross-section to compute the probability of a disruptive encounter as a function of birth cluster properties. We find that, contrary to prior work, the probability of disruption is small regardless of the cluster mass, and that it actually decreases rather than increases with cluster mass. Our results differ from prior work for three main reasons: (1) unlike in most previous work, we compute a velocity-dependent cross-section and properly integrate over the cluster mass-dependent velocity distribution of incoming stars; (2) we recognize that {approx}90% of clusters have lifetimes of a few crossing times, rather than the 10-100 Myr adopted in many earlier models; and (3) following recent observations, we adopt a mass-independent surface density for embedded clusters, rather than a mass-independent radius as assumed many earlier papers. Our results remove the tension between the dynamical limit and the meteoritic evidence, and suggest that the Sun was born in a massive cluster. A corollary to this result is that close encounters in the Sun's birth cluster are highly unlikely to truncate the Kuiper Belt unless the Sun was born in one of the unusual clusters that survived for tens of Myr. However, we find that encounters could plausibly produce highly eccentric Kuiper Belt objects such as Sedna.

Dukes, Donald; Krumholz, Mark R. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)

2012-07-20T23:59:59.000Z

Note: This page contains sample records for the topic "four-stage cluster sampling" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

THE SLOAN DIGITAL SKY SURVEY QUASAR LENS SEARCH. II. STATISTICAL LENS SAMPLE FROM THETHIRD DATA RELEASE  

Science Conference Proceedings (OSTI)

We report the first results of our systematic search for strongly lensed quasars using the spectroscopically confirmed quasars in the Sloan Digital Sky Survey (SDSS). Among 46,420 quasars from the SDSS Data Release 3 ({approx}4188 deg{sup 2}), we select a subsample of 22,683 quasars that are located at redshifts between 0.6 and 2.2 and are brighter than the Galactic extinction corrected i-band magnitude of 19.1. We identify 220 lens candidates from the quasar subsample, for which we conduct extensive and systematic follow-up observations in optical and near-infrared wavebands, in order to construct a complete lensed quasar sample at image separations between 1-inch and 20-inch and flux ratios of faint to bright lensed images larger than 10{sup -0.5}. We construct a statistical sample of 11 lensed quasars. Ten of these are galaxy-scale lenses with small image separations ({approx} 1-inch - 2-inch) and one is a large separation (15-inch) system which is produced by a massive cluster of galaxies, representing the first statistical sample of lensed quasars including both galaxy- and cluster-scale lenses. The Data Release 3 spectroscopic quasars contain an additional 11 lensed quasars outside the statistical sample.

Inada, N; Oguri, M; Becker, R H; Shin, M; Richards, G T; Hennawi, J F; White, R L; Pindor, B; Strauss, M A; Kochanek, C S; Johnston, D E; Gregg, M D; Kayo, I; Eisenstein, D; Hall, P B; Castander, F J; Clocchiatti, A; Chiu, K; Kawano, Y; Scranton, R; Frieman, J; Keeton, C R; Morokuma, T; Rix, H; Turner, E L; Burless, S; Brunner, R J; Sheldon, E S; Bahcall, N A; Fukugita, M

2007-09-13T23:59:59.000Z

442

Definition: Rock Sampling | Open Energy Information  

Open Energy Info (EERE)

Sampling Sampling Jump to: navigation, search Dictionary.png Rock Sampling Systematic rock sampling can be used to characterize a geothermal reservoir. The physical and chemical properties of rock samples provide important information for determining whether a power generation or heat utilization facility can be developed. Some general rock properties can be measured by visual inspection, but detailed properties require laboratory techniques. View on Wikipedia Wikipedia Definition A core sample is a cylindrical section of (usually) a naturally occurring substance. Most core samples are obtained by drilling with special drills into the substance, for example sediment or rock, with a hollow steel tube called a core drill. The hole made for the core sample is called the "core hole". A variety of core samplers exist to sample

443

Method and apparatus for data sampling  

DOE Patents (OSTI)

A method and apparatus for sampling radiation detector outputs and determining event data from the collected samples is described. The method uses high speed sampling of the detector output, the conversion of the samples to digital values, and the discrimination of the digital values so that digital values representing detected events are determined. The high speed sampling and digital conversion is performed by an A/D sampler that samples the detector output at a rate high enough to produce numerous digital samples for each detected event. The digital discrimination identifies those digital samples that are not representative of detected events. The sampling and discrimination also provides for temporary or permanent storage, either serially or in parallel, to a digital storage medium. 6 figures.

Odell, D.M.C.

1994-04-19T23:59:59.000Z

444

Fluid sampling system for a nuclear reactor  

DOE Patents (OSTI)

A system of extracting fluid samples, either liquid or gas, from the interior of a nuclear reactor containment utilizes a jet pump. To extract the sample fluid, a nonradioactive motive fluid is forced through the inlet and discharge ports of a jet pump located outside the containment, creating a suction that draws the sample fluid from the containment through a sample conduit connected to the pump suction port. The mixture of motive fluid and sample fluid is discharged through a return conduit to the interior of the containment. The jet pump and means for removing a portion of the sample fluid from the sample conduit can be located in a shielded sample grab station located next to the containment. A non-nuclear grade active pump can be located outside the grab sampling station and the containment to pump the nonradioactive motive fluid through the jet pump. 1 fig.

Lau, L.K.; Alper, N.I.

1994-11-22T23:59:59.000Z

445

Regression Models for Demand Reduction based on Cluster Analysis of Load Profiles  

E-Print Network (OSTI)

on Cluster Analysis of Load Profiles Nobuyuki Yamaguchi,on Cluster Analysis of Load Profiles Nobuyuki Yamaguchi,regressions, using actual load profile data of Pacific Gas

Kiliccote, Sila

2010-01-01T23:59:59.000Z

446

Two-dimensional visualization of cluster beams by microchannel plates  

E-Print Network (OSTI)

An advanced technique for a two-dimensional real time visualization of cluster beams in vacuum as well as of the overlap volume of cluster beams with particle accelerator beams is presented. The detection system consists of an array of microchannel plates (MCP) in combination with a phosphor screen which is read out by a CCD camera. This setup together with the ionization of a cluster beam by an electron or ion beam allows for spatial resolved investigations of the cluster beam position, size, and intensity. Moreover, since electrically uncharged clusters remain undetected, the operation in an internal beam experiment opens the way to monitor the overlap region and thus the position and size of an accelerator beam crossing an originally electrically neutral cluster jet. The observed intensity distribution of the recorded image is directly proportional to the convolution of the spatial ion beam and cluster beam intensities and is by this a direct measure of the two-dimensional luminosity distribution. This information can directly be used for the reconstruction of vertex positions as well as for an input for numerical simulations of the reaction zone. The spatial resolution of the images are dominated by the granularity of the complete MCP device and was found to be in the order of \\sigma~100 \\mu m.

Alfons Khoukaz; Daniel Bonaventura; Silke Grieser; Ann-Katrin Hergemöller; Esperanza Köhler; Alexander Täschner

2013-07-23T23:59:59.000Z