Powered by Deep Web Technologies
Note: This page contains sample records for the topic "halogen bulbs halo" 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.


1

GREEN LIVING Replace incandencent and halogen light bulbs with LED and CLFs  

E-Print Network [OSTI]

GREEN LIVING GUIDE ENERGY TRAVEL FOOD sustain yosef WATER Replace incandencent and halogen light for your laundry RESIST THAT SWITCH! Use natural light during the day, and no lights when you are gone USE MORE THAN YOU CAN EAT, reduce your waste stream DRINK FAIR TRADE COFFEE - Check out Conrad

Thaxton, Christopher S.

2

Jacketed lamp bulb envelope  

DOE Patents [OSTI]

A jacketed lamp bulb envelope includes a ceramic cup having an open end and a partially closed end, the partially closed end defining an aperture, a lamp bulb positioned inside the ceramic cup abutting the aperture, and a reflective ceramic material at least partially covering a portion of the bulb not abutting the aperture. The reflective ceramic material may substantially fill an interior volume of the ceramic cup not occupied by the bulb. The ceramic cup may include a structural feature for aiding in alignment of the jacketed lamp bulb envelope in a lamp. The ceramic cup may include an external flange about a periphery thereof. One example of a jacketed lamp bulb envelope includes a ceramic cup having an open end and a closed end, a ceramic washer covering the open end of the ceramic cup, the washer defining an aperture therethrough, a lamp bulb positioned inside the ceramic cup abutting the aperture, and a reflective ceramic material filling an interior volume of the ceramic cup not occupied by the bulb. A method of packing a jacketed lamp bulb envelope of the type comprising a ceramic cup with a lamp bulb disposed therein includes the steps of filling the ceramic cup with a flowable slurry of reflective material, and applying centrifugal force to the cup to pack the reflective material therein.

MacLennan, Donald A. (Gaithersburg, MD); Turner, Brian P. (Damascus, MD); Gitsevich, Aleksandr (Gaithersburg, MD); Bass, Gary K. (Mt. Airy, MD); Dolan, James T. (Frederick, MD); Kipling, Kent (Gaithersburg, MD); Kirkpatrick, Douglas A. (Great Falls, VA); Leng, Yongzhang (Damascus, MD); Levin, Izrail (Silver Spring, MD); Roy, Robert J. (Frederick, MD); Shanks, Bruce (Gaithersburg, MD); Smith, Malcolm (Alexandria, VA); Trimble, William C. (Columbia, MD); Tsai, Peter (Olney, MD)

2001-01-01T23:59:59.000Z

3

Waste Toolkit A-Z Light bulbs  

E-Print Network [OSTI]

Waste Toolkit A-Z Light bulbs Can I recycle light bulbs? It depends what type of bulbs you have of in the normal University waste bins (landfill waste). Energy saving bulbs and fluorescent tubes are classified light bulbs? Standard filament bulbs Put in the waste bin (landfill waste) as these are not classified

Melham, Tom

4

Lamp bulb with integral reflector  

DOE Patents [OSTI]

An improved electrodeless discharge lamp bulb includes an integral ceramic reflector as a portion of the bulb envelope. The bulb envelope further includes two pieces, a reflector portion or segment is cast quartz ceramic and a light transmissive portion is a clear fused silica. In one embodiment, the cast quartz ceramic segment includes heat sink fins or stubs providing an increased outside surface area to dissipate internal heat. In another embodiment, the quartz ceramic segment includes an outside surface fused to eliminate gas permeation by polishing.

Levin, Izrail (Silver Spring, MD); Shanks, Bruce (Gaithersburg, MD); Sumner, Thomas L. (Wheaton, MD)

2001-01-01T23:59:59.000Z

5

Halogenated solvent remediation  

DOE Patents [OSTI]

Methods for enhancing bioremediation of ground water contaminated with nonaqueous halogenated solvents are disclosed. An illustrative method includes adding an electron donor for microbe-mediated anaerobic reductive dehalogenation of the halogenated solvents, which electron donor enhances mass transfer of the halogenated solvents from residual source areas into the aqueous phase of the ground water. Illustrative electron donors include C.sub.2-C.sub.4 carboxylic acids and hydroxy acids, salts thereof, esters of C.sub.2-C.sub.4 carboxylic acids and hydroxy acids, and mixtures thereof, of which lactic acid, salts of lactic acid--such as sodium lactate, lactate esters, and mixtures thereof are particularly illustrative. The microbes are either indigenous to the ground water, or such microbes can be added to the ground water in addition to the electron donor.

Sorenson, Jr., Kent S. (Windsor, CO)

2008-11-11T23:59:59.000Z

6

Halogenation of cobalt dicarbollide  

DOE Patents [OSTI]

A method for selectively adding chlorine, bromine, or iodine to cobalt dicarbollide anions by means of electrophilic substitution reactions. Halogens are added only to the B10 and B10{prime} positions of the anion. The process involves use of hypohalous acid or N-halosuccinimide or gaseous chlorine in the presence of iron. 1 fig.

Hurlburt, P.K.; Abney, K.D.; Kinkead, S.A.

1997-05-20T23:59:59.000Z

7

Changing How You Choose Light Bulbs | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Bulbs July 12, 2010 - 7:30am Addthis Elizabeth Spencer Communicator, National Renewable Energy Laboratory Last month, the Federal Trade Commission announced that light bulbs will...

8

HELSINKI UNIVERSITY OF TECHNOLOGY ENE-47.153 Halogens, dioxins/Halogens, dioxins/furansfurans  

E-Print Network [OSTI]

HELSINKI UNIVERSITY OF TECHNOLOGY ENE-47.153 Halogens, dioxins/Halogens, dioxins and fuel gases ·· Dioxins/Dioxins/furansfurans formation and controlformation and control ·· Other-halogen compoundsOrgano-halogen compounds 2,3,7,8 tetrachloro dibenzo - p- dioxin PCB furan 2

Zevenhoven, Ron

9

How Energy-Efficient Light Bulbs Compare with Traditional Incandescent...  

Broader source: Energy.gov (indexed) [DOE]

could save you about 50 per year in energy costs when you replace 15 traditional incandescent bulbs in your home. Energy-efficient light bulbs are available today and could save...

10

2, 14571486, 2005 Halogens in peat  

E-Print Network [OSTI]

BGD 2, 14571486, 2005 Halogens in peat porewater H. Biester et al. Title Page Abstract Discussions is the access reviewed discussion forum of Biogeosciences Halogens in porewater of peat bogs the role of peat decomposition and dissolved organic matter H. Biester 1 , D. Selimovic 1 , S. Hemmerich 1

Paris-Sud XI, Universit de

11

Consumer Light Bulb Changes: Briefing and Resources for Media...  

Energy Savers [EERE]

background information on the new legislation and the types of energy-efficient lighting available today. Consumer Light Bulb Changes: Briefing and Resources for Media and...

12

Consumer Light Bulb Changes: Briefing and Resources for Media...  

Broader source: Energy.gov (indexed) [DOE]

flux") - CFL: Compact Fluorescent Lamp: The curly fluorescent bulbs - LED: Light Emitting Diode: more recently emerging technology, also called "solid state lighting" as it is...

13

Energy efficient alternatives to halogen torchieres  

SciTech Connect (OSTI)

A series of novel energy efficient torchiere systems have been developed using compact fluorescent lamps (CFLs). These systems were studied photometrically and compared with the performance of traditional commercially available tungsten halogen sources. Gonio-photometric data and power assessments indicate that significant lighting energy savings can be obtained by utilizing CFL sources instead of standard tungsten halogen sources. This energy savings is jointly due to the higher source efficacy of the CFLs and the surprisingly poor performance of the imported 300 Watt halogen lamps. Experimental data shows that a 50 to 60 Watt CFL will effectively lumen match a variety of 300 Watt tungsten halogen sources with 5 to 10 times the efficacy. CFL torchieres have additional benefits of higher power quality and cooler lamp operating temperature, making them safer fixtures.

Siminovitch, M.; Marr, L.; Mitchell, J.; Page, E.

1997-03-01T23:59:59.000Z

14

E-Print Network 3.0 - active halogen species Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

organo-halogen gases or solvents. The most abundant... Zevenhoven & Kilpinen Halogens, dioxinsfurans 17.6.2001 7-1 Chapter 7 Halogens, dioxinsfurans 7... .1 Introduction The...

15

FIELD SCREENING FOR HALOGENATED VOLATILE ORGANIC COMPOUNDS  

SciTech Connect (OSTI)

Western Research Institute (WRI) initiated exploratory work towards the development of new field screening methodology and a test kit to measure halogenated volatile organic compounds (VOCs) in the field. Heated diode and corona discharge sensors are commonly used to detect leaks of refrigerants from air conditioners, freezers, and refrigerators. They are both selective to the presence of carbon-halogen bonds. Commercially available heated diode and corona discharge leak detectors were procured and evaluated for halogenated VOC response. The units were modified to provide a digital readout of signal related to VOC concentration. Sensor response was evaluated with carbon tetrachloride and tetrachloroethylene (perchloroethylene, PCE), which represent halogenated VOCs with and without double bonds. The response characteristics were determined for the VOCs directly in headspace in Tedlar bag containers. Quantitation limits in air were estimated. Potential interferences from volatile hydrocarbons, such as toluene and heptane, were evaluated. The effect of humidity was studied also. The performance of the new devices was evaluated in the laboratory by spiking soil samples and monitoring headspace for halogenated VOCs. A draft concept of the steps for a new analytical method was outlined. The results of the first year effort show that both devices show potential utility for future analytical method development work towards the goal of developing a portable test kit for screening halogenated VOCs in the field.

John F. Schabron; Joseph F. Rovani Jr.; Theresa M. Bomstad

2002-06-01T23:59:59.000Z

16

Crystallographic studies on enzymatic halogenation of natural products  

E-Print Network [OSTI]

Halogenated natural products are common and serve roles as hormones, pesticides, antibiotics, and anti-tumor agents. The incorporation of a halogen atom into an organic scaffold can tune the molecule's potency and selectivity, ...

Blasiak, Leah Cameron

2008-01-01T23:59:59.000Z

17

Method and apparatus for low temperature destruction of halogenated hydrocarbons  

DOE Patents [OSTI]

A method and apparatus for decomposing halogenated hydrocarbons are provided. The halogenated hydrocarbon is mixed with solvating agents and maintained in a predetermined atmosphere and at a predetermined temperature. The mixture is contacted with recyclable reactive material for chemically reacting with the recyclable material to create dehalogenated hydrocarbons and halogenated inorganic compounds. A feature of the invention is that the process enables low temperature destruction of halogenated hydrocarbons.

Reagen, William Kevin (Stillwater, MN); Janikowski, Stuart Kevin (Idaho Falls, ID)

1999-01-01T23:59:59.000Z

18

How Many CASTLE Bulbs Would You Need To Match the Brightness of the Sun?  

E-Print Network [OSTI]

;Suppose that you have two household incandescent bulbs: one is labeled "60W," the other "100W." If you try incandescent bulb and a 9W fluorescent bulb. Which one makes your room brighter? It's not what you might expect... in fact, they look about the same! The incandescent bulb emits a broad spectrum of visible and infrared

Collar, Juan I.

19

Zevenhoven & Kilpinen Halogens, dioxins/furans 17.6.2001 7-1 Chapter 7 Halogens,  

E-Print Network [OSTI]

Zevenhoven & Kilpinen Halogens, dioxins/furans 17.6.2001 7-1 Chapter 7 Halogens, dioxins/furans 7 in Figure 7.1. The polychlorinated dibenzo -(p) dioxins and -furans (PCDD/Fs) that are found in PCBs and may, dioxins/furans 17.6.2001 7-2 2,3,7,8 tetrachloro dibenzo - p- dioxin PCB furan 2,3,7,8 tetrachlorodibenzo

Zevenhoven, Ron

20

Retention of Halogens in Waste Glass  

SciTech Connect (OSTI)

In spite of their potential roles as melting rate accelerators and foam breakers, halogens are generally viewed as troublesome components for glass processing. Of five halogens, F, Cl, Br, I, and At, all but At may occur in nuclear waste. A nuclear waste feed may contain up to 10 g of F, 4 g of Cl, and ?100 mg of Br and I per kg of glass. The main concern is halogen volatility, producing hazardous fumes and particulates, and the radioactive iodine 129 isotope of 1.7x10^7-year half life. Because F and Cl are soluble in oxide glasses and tend to precipitate on cooling, they can be retained in the waste glass in the form of dissolved constituents or as dispersed crystalline inclusions. This report compiles known halogen-retention data in both high-level waste (HLW) and low-activity waste (LAW) glasses. Because of its radioactivity, the main focus is on I. Available data on F and Cl were compiled for comparison. Though Br is present in nuclear wastes, it is usually ignored; no data on Br retention were found.

Hrma, Pavel R.

2010-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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

Process for removal of hydrogen halides or halogens from incinerator gas  

DOE Patents [OSTI]

A process for reducing the amount of halogens and halogen acids in high temperature combustion gas and through their removal, the formation of halogenated organics at lower temperatures, with the reduction being carried out electrochemically by contacting the combustion gas with the negative electrode of an electrochemical cell and with the halogen and/or halogen acid being recovered at the positive electrode.

Huang, H.S.; Sather, N.F.

1987-08-21T23:59:59.000Z

22

Radiation Dose-Volume Effects and the Penile Bulb  

SciTech Connect (OSTI)

The dose, volume, and clinical outcome data for penile bulb are reviewed for patients treated with external-beam radiotherapy. Most, but not all, studies find an association between impotence and dosimetric parameters (e.g., threshold doses) and clinical factors (e.g., age, comorbid diseases). According to the data available, it is prudent to keep the mean dose to 95% of the penile bulb volume to <50 Gy. It may also be prudent to limit the D70 and D90 to 70 Gy and 50 Gy, respectively, but coverage of the planning target volume should not be compromised. It is acknowledged that the penile bulb may not be the critical component of the erectile apparatus, but it seems to be a surrogate for yet to be determined structure(s) critical for erectile function for at least some techniques.

Roach, Mack, E-mail: mroach@radonc.ucsf.ed [Department of Radiation Oncology, University of California-San Francisco, San Francisco, CA (United States); Nam, Jiho [Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC (United States); Gagliardi, Giovanna [Department of Medical Physics, Karolinska University Hospital and Karolinska Institutet, Stockholm (Sweden); El Naqa, Issam; Deasy, Joseph O. [Department of Radiation Oncology, School of Medicine, Washington University in St. Louis, St. Louis, MO (United States); Marks, Lawrence B. [Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC (United States)

2010-03-01T23:59:59.000Z

23

Shapes of dark matter halos  

E-Print Network [OSTI]

I present an analysis of the density shapes of dark matter halos in LCDM and LWDM cosmologies. The main results are derived from a statistical sample of galaxy-mass halos drawn from a high resolution LCDM N-body simulation. Halo shapes show significant trends with mass and redshift: low-mass halos are rounder than high mass halos, and, for a fixed mass, halos are rounder at low z. Contrary to previous expectations, which were based on cluster-mass halos and non-COBE normalized simulations, LCDM galaxy-mass halos at z=0 are not strongly flattened, with short to long axis ratios of s = 0.70 +/- 0.17. I go on to study how the shapes of individual halos change when going from a LCDM simulation to a simulation with a warm dark matter power spectrum (LWDM). Four halos were compared, and, on average, the WDM halos are more spherical than their CDM counterparts (s =0.77 compared to s = 0.71). A larger sample of objects will be needed to test whether the trend is significant.

James S. Bullock

2001-06-21T23:59:59.000Z

24

Text-Alternative Version: L Prize: The Race for Super Efficient Light Bulbs  

Broader source: Energy.gov [DOE]

Below is the text-alternative version of the L Prize: The Race for Super Efficient Light Bulbs webcast.

25

E-Print Network 3.0 - anesthesiques halogenes pendant Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Collection: Chemistry 38 HELSINKI UNIVERSITY OF TECHNOLOGY ENE-47.153 Halogens, dioxinsHalogens, dioxinsfuransfurans Summary: HELSINKI UNIVERSITY OF TECHNOLOGY ENE-47.153...

26

Free Energy Efficiency Kit includes CFL light bulbs,  

E-Print Network [OSTI]

Free Energy Efficiency Kit Kit includes CFL light bulbs, spray foam, low-flow shower head, and more! Building Science 101 Presentation BPI Certified Building Professionals will present home energy efficiency for discounted energy assessments. FREE HOME ENERGY EFFICIENCY SEMINAR N e w R i ver L i g ht & Pow e r a n d W

Rose, Annkatrin

27

FIELD SCREENING FOR HALOGENATED VOLATILE ORGANIC COMPOUNDS  

SciTech Connect (OSTI)

Western Research Institute (WRI) is continuing work toward the development of new screening methodology and a test kit to measure halogenated volatile organic compounds (VOCs) in the field. Heated diode and corona discharge sensors are commonly used to detect leaks of refrigerants from air conditioners, freezers, and refrigerators. They are both selective to the presence of halogens. In prior work, the devices were tested for response to carbon tetrachloride, heptane, toluene, and water vapors. In the current work, sensor response was evaluated with sixteen halogenated VOCs relative to carbon tetrachloride. The results show that the response of the various chlorinated VOCs is within an order of magnitude of the response to carbon tetrachloride for each of the sensors. Thus, for field screening a single response factor can be used. Both types of leak detectors are being further modified to provide an on-board LCD signal readout, which is related to VOC concentration. The units will be fully portable and will operate with 115-V line or battery power. Signal background, noise level, and response data on the Bacharach heated diode detector and the TIF corona discharge detector show that when the response curves are plotted against the log of concentration, the plot is linear to the upper limit for the particular unit, with some curvature at lower levels. When response is plotted directly against concentration, the response is linear at the low end and is curved at the high end. The dynamic ranges for carbon tetrachloride of the two devices from the lower detection limit (S/N=2) to signal saturation are 4-850 vapor parts per million (vppm) for the corona discharge unit and 0.01-70 vppm for the heated diode unit. Additional circuit modifications are being made to lower the detection limit and increase the dynamic response range of the corona discharge unit. The results indicate that both devices show potential utility for future analytical method development work toward the goal of developing a portable test kit for screening halogenated VOCs in the field.

John F. Schabron; Joseph F. Rovani, Jr.; Theresa M. Bomstad

2003-07-01T23:59:59.000Z

28

Tired of changing light bulbs AND want to save money? Still using 100 year-old technology?  

E-Print Network [OSTI]

THE COMPACT FLUORESCENT LIGHT BULB CHALLENGE! · A 23 W Compact bulb gives the same light as a 100W regular with compact fluorescent bulbs! Toss `Em Install `Em Most big stores stock them. We bought ours at Costco @ $2Tired of changing light bulbs AND want to save money? Still using 100 year-old technology? TAKE

Glashausser, Charles

29

A Bit About Bulbs Night temperatures are cool, the air is almost crisp. The vegetable harvest is tapering  

E-Print Network [OSTI]

work their way down and stems go up where they belong. Purchase from reliable dealers to assure quality is the general rule to follow. If you are dealing with a strangely shaped bulb species that doesn't seem to have of moisture. A quality bulb is a large bulb; it will produce larger flowers and more of them. The bulb should

New Hampshire, University of

30

Metal halogen battery construction with improved technique for producing halogen hydrate  

DOE Patents [OSTI]

An improved electrical energy storage system comprising, at least one cell having a positive electrode and a negative electrode separated by aqueous electrolyte, a store means wherein halogen hydrate is formed and stored as part of an aqueous material having a liquid level near the upper part of the store, means for circulating electrolyte through the cell, conduit means for transmitting halogen gas formed in the cell to a hydrate forming apparatus associated with the store, said hydrate forming apparatus including, a pump to which there is introduced quantities of the halogen gas and chilled water, said pump being located in the store and an outlet conduit leading from the pump and being substantially straight and generally vertically disposed and having an exit discharge into the gas space above the liquid level in the store, and wherein said hydrate forming apparatus is highly efficient and very resistant to plugging or jamming. The disclosure also relates to an improved method for producing chlorine hydrate in zinc chlorine batteries.

Fong, Walter L. (Royal Oak, MI); Catherino, Henry A. (Rochester, MI); Kotch, Richard J. (Mt. Clemens, MI)

1983-01-01T23:59:59.000Z

31

5, 29732988, 2005 Stratospheric HALOE  

E-Print Network [OSTI]

ACPD 5, 2973­2988, 2005 Stratospheric HALOE climatology J.-U. Groo? and J. M. Russell III Title and Physics Discussions Technical note: A stratospheric climatology for O3, H2O and CH4 derived from HALOE­2988, 2005 Stratospheric HALOE climatology J.-U. Groo? and J. M. Russell III Title Page Abstract Introduction

Paris-Sud XI, Université de

32

Photochemical reductive elimination of halogen from transition metal complexes  

E-Print Network [OSTI]

This thesis is focused on the synthesis and study of transition metal complexes that undergo halogen elimination when irradiated with UV and visible light. This chemistry is relevant for solar energy storage schemes in ...

Cook, Timothy R. (Timothy Raymond), 1982-

2010-01-01T23:59:59.000Z

33

Halogenated naphthyl methoxy piperidines for mapping serotonin transporter sites  

DOE Patents [OSTI]

Halogenated naphthyl methoxy piperidines having a strong affinity for the serotonin transporter are disclosed. Those compounds can be labeled with positron-emitting and/or gamma emitting halogen isotopes by a late step synthesis that maximizes the useable lifeterm of the label. The labeled compounds are useful for localizing serotonin transporter sites by positron emission tomography and/or single photon emission computed tomography.

Goodman, Mark M. (Atlanta, GA); Faraj, Bahjat (Lithonia, GA)

1999-01-01T23:59:59.000Z

34

Halogenated naphthyl methoxy piperidines for mapping serotonin transporter sites  

DOE Patents [OSTI]

Halogenated naphthyl methoxy piperidines having a strong affinity for the serotonin transporter are disclosed. Those compounds can be labeled with positron-emitting and/or gamma emitting halogen isotopes by a late step synthesis that maximizes the useable lifeterm of the label. The labeled compounds are useful for localizing serotonin transporter sites by positron emission tomography and/or single photon emission computed tomography.

Goodman, M.M.; Faraj, B.

1999-07-06T23:59:59.000Z

35

Treatment of halogen-containing waste and other waste materials  

DOE Patents [OSTI]

A process for treating a halogen-containing waste material. The process provides a bath of molten glass containing a sacrificial metal oxide capable of reacting with a halogen in the waste material. The sacrificial metal oxide is present in the molten glass in at least a stoichiometric amount with respect to the halogen in the waste material. The waste material is introduced into the bath of molten glass to cause a reaction between the halogen in the waste material and the sacrificial metal oxide to yield a metal halide. The metal halide is a gas at the temperature of the molten glass. The gaseous metal halide is separated from the molten glass and contacted with an aqueous scrubber solution of an alkali metal hydroxide to yield a metal hydroxide or metal oxide-containing precipitate and a soluble alkali metal halide. The precipitate is then separated from the aqueous scrubber solution. The molten glass containing the treated waste material is removed from the bath as a waste glass. The process of the invention can be used to treat all types of waste material including radioactive wastes. The process is particularly suited for separating halogens from halogen-containing wastes.

Forsberg, Charles W. (Oak Ridge, TN); Beahm, Edward C. (Oak Ridge, TN); Parker, George W. (Concord, TN)

1997-01-01T23:59:59.000Z

36

Treatment of halogen-containing waste and other waste materials  

DOE Patents [OSTI]

A process is described for treating a halogen-containing waste material. The process provides a bath of molten glass containing a sacrificial metal oxide capable of reacting with a halogen in the waste material. The sacrificial metal oxide is present in the molten glass in at least a stoichiometric amount with respect to the halogen in the waste material. The waste material is introduced into the bath of molten glass to cause a reaction between the halogen in the waste material and the sacrificial metal oxide to yield a metal halide. The metal halide is a gas at the temperature of the molten glass. The gaseous metal halide is separated from the molten glass and contacted with an aqueous scrubber solution of an alkali metal hydroxide to yield a metal hydroxide or metal oxide-containing precipitate and a soluble alkali metal halide. The precipitate is then separated from the aqueous scrubber solution. The molten glass containing the treated waste material is removed from the bath as a waste glass. The process of the invention can be used to treat all types of waste material including radioactive wastes. The process is particularly suited for separating halogens from halogen-containing wastes. 3 figs.

Forsberg, C.W.; Beahm, E.C.; Parker, G.W.

1997-03-18T23:59:59.000Z

37

Westinghouse Pays $50,000 Civil Penalty to Resolve Light Bulb...  

Office of Environmental Management (EM)

of Energy has successfully resolved the enforcement case against Westinghouse Lighting Corporation for failure to certify its light bulbs as compliant with DOE's federal...

38

Symmetry Projected Density Functional Theory and Neutron Halos  

E-Print Network [OSTI]

The appearance of halo phenomena near the drip line nuclei has challenged our traditional understanding of the nuclei as an incompressible charged liquid drop and extended nuclear physics to low density and inhomogeneous system, where the coupling to the continuum has to be treated in a consistent way. Recently Relativistic Hartree Bogoliubov (RHB) theory in the continuum has been applied successfully to the description of halo phenomena in light and medium heavy nuclei [1, 2, 3]. This theory provides a self-consistent treatment of pairing correlation in the presence of the continuum and allows a microscopic description of halo phenomena in the framework of density functional theory. Essential conditions for the formation of a neutron halo have been found: (a) the Fermi surface of the neutrons has to

unknown authors

39

Magnesium Isotopes in Halo Stars  

E-Print Network [OSTI]

We have determined Mg isotope ratios in halo field dwarfs and giants in the globular cluster M71 based on high S/N high spectral resolution (R = 10$^5$) Keck HIRES spectra. Unlike previous claims of an important contribution from intermediate-mass AGB stars to the Galactic halo, we find that our $^{26}$Mg/$^{24}$Mg ratios can be explained by massive stars.

Jorge Melendez; Judith G. Cohen

2007-08-29T23:59:59.000Z

40

Halogenated 1'-methyl-1,2'-bipyrroles (MBPs) in the Norwestern Atlantic  

E-Print Network [OSTI]

Halogenated 1'-methyl-1,2'-bipyrroles (MBPs) are a distinctive class of marine organic compounds. They are naturally produced, they have a unique carbon structure, they are highly halogenated, and they bioaccumulate in ...

Pangallo, Kristin C

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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

How to upgrade your incandescent light bulbs Many people are choosing replacements for their standard incandescent light bulbs to save money or energy, because they've heard of new LED  

E-Print Network [OSTI]

How to upgrade your incandescent light bulbs Many people are choosing replacements for their standard incandescent light bulbs to save money or energy, because they've heard of new LED options, or in anticipation of the phase-out of standard incandescent bulbs in the U.S. starting in 2012. If you've shopped

Bystroff, Chris

42

E-Print Network 3.0 - agents anesthesiques halogenes Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Chemistry 17 Incompatible Chemicals -Partial list Chemical Incompatibilities Summary: , carbon tetrachloride or other chlorinated hydrocarbons, carbon dioxide, halogens Ammonia...

43

Symmetric and asymmetric halogen-containing metallocarboranylporphyrins and uses thereof  

DOE Patents [OSTI]

The present invention is directed to low toxicity boronated compounds and methods for their use in the treatment, visualization, and diagnosis of tumors. More specifically, the present invention is directed to low toxicity halogenated, carborane-containing 5,10,15,20-tetraphenylporphyrin compounds and methods for their use particularly in boron neutron capture therapy (BNCT) and photodynamic therapy (PDT) for the treatment of tumors of the brain, head and neck, and surrounding tissue. The invention is also directed to using these halogenated, carborane-containing tetraphenylporphyrin compounds in methods of tumor imaging and/or diagnosis such as MRI, SPECT, or PET.

Miura, Michiko; Wu, Haitao

2013-05-21T23:59:59.000Z

44

Method for selective dehalogenation of halogenated polyaromatic compounds  

DOE Patents [OSTI]

A method for dehalogenating halogenated polyaromatic compounds is provided wherein the polyaromatic compounds are mixed with a hydrogen donor solvent and a carbon catalyst in predetermined proportions, the mixture is maintained at a predetermined pressure, and the mixture is heated to a predetermined temperature and for a predetermined time.

Farcasiu, Malvina (Pittsburgh, PA); Petrosius, Steven C. (Library, PA)

1994-01-01T23:59:59.000Z

45

E-Print Network 3.0 - accessory olfactory bulb Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

search results for: accessory olfactory bulb Page: << < 1 2 3 4 5 > >> 1 Dcculopmentul Brain Rescurch. 70 (1W2) 279-22 O 1992 Elsevier Science Publishers B.V.All rights reserved...

46

600 New Lights Bulbs to Improve Energy Efficiency at DOE | Department...  

Broader source: Energy.gov (indexed) [DOE]

our Washington, D.C., Forrestal North Building canopy with state of the art Light Emitting Diode (LED) fixtures. Every new bulb now uses just 23 watts instead of 205 watts....

47

2.44a0005 Physiology of the Main Olfactory Bulb Matthew Ennis1  

E-Print Network [OSTI]

-inhibition 27 2.44.6.4.2 Lateral inhibition 27 2.44.6.4.3 Role of Ca2 influx through NMDA receptors and voltage.44.8 Neurophysiology of Primary Olfactory Cortical Inputs to Main Olfactory Bulb 29 2.44.9 Oscillations and Synchrony in Main Olfactory Bulb 29 2.44.9.1 Oscillations 29 2.44.9.1.1 Theta rhythm 30 2.44.9.1.2 Gamma rhythm 30 2

Hayar, Abdallah

48

Interrelationships between air velocity and natural wet-bulb thermometer response  

E-Print Network [OSTI]

INTERRELATIONSHIPS BETWEEN AIR VFLOCITY ANO NATURAL WET-BULB THERMOMETER RESPONSE A Thesis by NATHAN GLENN JONES Submitted to the Graduate Colleqe of Texas ASM University i n partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE AUGUST 1983 Major Subject: Industrial Hygiene INTERRELATIONSHIPS BETWEEN AIR VELOCITY AND NATURAL WET-BULB THERMOMETER RESPONSE A Thesis by NATHAN GLENN JONES Approved as to style an content by: airman o ommittee er Member ~~' A~ Member...

Jones, Nathan Glenn

1983-01-01T23:59:59.000Z

49

Chem 115Lithium-Halogen ExchangeMyers RLi + R'X RX + R'Li  

E-Print Network [OSTI]

Chem 115Lithium-Halogen ExchangeMyers RLi + R'X RX + R'Li Lithium-halogen exchange reactions are essentially inert. 2 t-BuLi t-BuI + RLi t-BuLi isobutene + isobutane + LiI Lithium-halogen exchange reactions, and lithium iodide. H OEtBr H H OEtLi H1.1 eq n-BuLi Et2O, !80 C Lau, K. S.; Schlosser, M. J. Org. Chem. 1978

50

Unbound particles in dark matter halos  

SciTech Connect (OSTI)

We investigate unbound dark matter particles in halos by tracing particle trajectories in a simulation run to the far future (a = 100). We find that the traditional sum of kinetic and potential energies is a very poor predictor of which dark matter particles will eventually become unbound from halos. We also study the mass fraction of unbound particles, which increases strongly towards the edges of halos, and decreases significantly at higher redshifts. We discuss implications for dark matter detection experiments, precision calibrations of the halo mass function, the use of baryon fractions to constrain dark energy, and searches for intergalactic supernovae.

Behroozi, Peter S.; Wechsler, Risa H. [Kavli Institute for Particle Astrophysics and Cosmology, Physics Department, Stanford University and SLAC National Accelerator Laboratory 2575 Sand Hill Road, Menlo Park, CA (United States); Loeb, Abraham, E-mail: behroozi@stanford.edu, E-mail: aloeb@cfa.harvard.edu, E-mail: rwechsler@stanford.edu [Department of Astronomy, Harvard University 60 Garden St, Cambridge, MA (United States)

2013-06-01T23:59:59.000Z

51

Nuclear halo and its scaling laws  

E-Print Network [OSTI]

We have proposed a procedure to extract the probability for valence particle being out of the binding potential from the measured nuclear asymptotic normalization coefficients. With this procedure, available data regarding the nuclear halo candidates are systematically analyzed and a number of halo nuclei are confirmed. Based on these results we have got a much relaxed condition for nuclear halo occurrence. Furthermore, we have presented the scaling laws for the dimensionless quantity $/R^{2}$ of nuclear halo in terms of the analytical expressions of the expectation value for the operator $r^{2}$ in a finite square-well potential.

Z. H. Liu; X. Z. Zhang; H. Q. Zhang

2004-02-06T23:59:59.000Z

52

Spatial assessment of net mercury emissions from the use of fluorescent bulbs  

SciTech Connect (OSTI)

While fluorescent lighting is an important technology for reducing electrical energy demand, mercury used in the bulbs is an ongoing concern. Using state and country level data, net emissions of mercury from the marginal use of fluorescent lightbulbs are examined for a base year of 2004 for each of the 50 United States and 130 countries. Combustion of coal for electric power generation is generally the largest source of atmospheric mercury pollution; reduction in electricity demand from the substitution of incandescent bulbs with fluorescents leads to reduced mercury emissions during the use of the bulb. This analysis considers the local mix of power sources, coal quality, thermal conversion efficiencies, distribution losses, and any mercury control technologies that might be in place. Emissions of mercury from production and end-of-life treatment of the bulbs are also considered, providing a life-cycle perspective. Net reductions in mercury over the entire life cycle range from -1.2 to 97 mg per bulb depending on the country. The consequences for atmospheric mercury emissions of several policy scenarios are also discussed. 46 refs., 4 figs., 3 tabs.

Matthew J. Eckelman; Paul T. Anastas; Julie B. Zimmerman [Yale University, New Haven, CT (United States). Department of Chemical Engineering

2008-11-15T23:59:59.000Z

53

Preliminary assessment of halogenated alkanes as vapor-phase tracers  

SciTech Connect (OSTI)

New tracers are needed to evaluate the efficiency of injection strategies in vapor-dominated environments. One group of compounds that seems to meet the requirements for vapor-phase tracing are the halogenated alkanes (HCFCs). HCFCs are generally nontoxic, and extrapolation of tabulated thermodynamic data indicate that they will be thermally stable and nonreactive in a geothermal environment. The solubilities and stabilities of these compounds, which form several homologous series, vary according to the substituent ratios of fluorine, chlorine, and hydrogen. Laboratory and field tests that will further define the suitability of HCFCs as vapor-phase tracers are under way.

Adams, Michael C.; Moore, Joseph N.; Hirtz, Paul

1991-01-01T23:59:59.000Z

54

Efficient and Regioselective Halogenations of 2-Amino-1,3-thiazoles with Copper Salts  

E-Print Network [OSTI]

Efficient and Regioselective Halogenations of 2-Amino-1,3-thiazoles with Copper Salts Fabrice G. Halogenations proceed easily in the presence of copper(I) or copper(II) chlorides, bromides, or iodides directly in solution or with supported copper halides. 1,3-Thiazole rings appear in many compounds that exhibit

Shen, Jun

55

On mini-halo encounters with stars  

E-Print Network [OSTI]

We study, analytically and numerically, the energy input into dark matter mini-haloes by interactions with stars. We find that the fractional energy input in simulations of Plummer spheres agrees well with the impulse approximation for small and large impact parameters, with a rapid transition between these two regimes. Using the impulse approximation the fractional energy input at large impact parameters is fairly independent of the mass and density profile of the mini-halo, however low-mass mini-haloes experience a greater fractional energy input in close encounters. We formulate a fitting function which encodes these results and use it to estimate the disruption timescales of mini-haloes, taking into account the stellar velocity dispersion and mass distribution. For mini-haloes with mass M< {\\cal O}(10^{-7} M_{\\odot} on typical orbits which pass through the disc, we find that the estimated disruption timescales are independent of mini-halo mass, and are of order the age of the Milky Way. For more massive mini-haloes the estimated disruption timescales increase rapidly with increasing mass.

Anne M. Green; Simon P. Goodwin

2006-12-11T23:59:59.000Z

56

Simulating the Gaseous Halos of Galaxies  

E-Print Network [OSTI]

Observations of local X-ray absorbers, high-velocity clouds, and distant quasar absorption line systems suggest that a significant fraction of baryons may reside in multi-phase, low-density, extended, ~100 kpc, gaseous halos around normal galaxies. We present a pair of high-resolution SPH (smoothed particle hydrodynamics) simulations that explore the nature of cool gas infall into galaxies, and the physical conditions necessary to support the type of gaseous halos that seem to be required by observations. The two simulations are identical other than their initial gas density distributions: one is initialized with a standard hot gas halo that traces the cuspy profile of the dark matter, and the other is initialized with a cored hot halo with a high central entropy, as might be expected in models with early pre-heating feedback. Galaxy formation proceeds in dramatically different fashions in these two cases. While the standard cuspy halo cools rapidly, primarily from the central region, the cored halo is quasi-stable for ~4 Gyr and eventually cools via the fragmentation and infall of clouds from ~100 kpc distances. After 10 Gyr of cooling, the standard halo's X-ray luminosity is ~100 times current limits and the resultant disk galaxy is twice as massive as the Milky Way. In contrast, the cored halo has an X-ray luminosity that is in line with observations, an extended cloud population reminiscent of the high-velocity cloud population of the Milky Way, and a disk galaxy with half the mass and ~50% more specific angular momentum than the disk formed in the low-entropy simulation. These results suggest that the distribution and character of halo gas provides an important testing ground for galaxy formation models and may be used to constrain the physics of galaxy formation.

Tobias Kaufmann; James S. Bullock; Ari Maller; Taotao Fang

2008-01-28T23:59:59.000Z

57

The Hazards of Use and Disposal of Compact Fluorescent Bulbs Compact fluorescent lights (aka. CFLs) work by exciting a phosphorous coating within the tube to emit  

E-Print Network [OSTI]

The Hazards of Use and Disposal of Compact Fluorescent Bulbs Compact fluorescent lights (aka. CFLs FLUORESCENT BULB? Because there is such a small amount of mercury in CFLs, the greatest hazard exposure the bulb to be an efficient light source. By comparison, older home thermometers contain 500 milligrams

Maroncelli, Mark

58

Labeling energy cost on light bulbs lowers implicit discount rates Jihoon Min a  

E-Print Network [OSTI]

levels that could be achieved if the most energy-efficient and cost-effective end-use technologiesAnalysis Labeling energy cost on light bulbs lowers implicit discount rates Jihoon Min a , Ins L of five, lowering barriers to adoption of energy efficient alternatives with higher up-front costs

Michalek, Jeremy J.

59

Volunteer Potato Density Influences Critical Time of Weed Removal in Bulb Onion  

E-Print Network [OSTI]

Volunteer Potato Density Influences Critical Time of Weed Removal in Bulb Onion Martin M. Williams II, Corey V. Ransom, and W. Mack Thompson* Volunteer potato is highly competitive with onion and few control tactics are effective for removing this weed from an onion crop. Both volunteer potato density

Sims, Gerald K.

60

Frequently Asked Questions Information on Compact Fluorescent Light Bulbs (CFLs) and Mercury  

E-Print Network [OSTI]

Frequently Asked Questions Information on Compact Fluorescent Light Bulbs (CFLs) and Mercury emissions equivalent to those of more than 800,000 cars. Do CFLs contain mercury? CFLs contain a very small amount of mercury sealed within the glass tubing ­ an average of 5 milligrams ­ about the amount

Jia, Songtao

Note: This page contains sample records for the topic "halogen bulbs halo" 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

Halo occupation numbers and galaxy bias  

E-Print Network [OSTI]

We propose a heuristic model that displays the main features of realistic theories for galaxy bias. We show that the low-order clustering statistics of the dark-matter distribution depend almost entirely on the locations and density profiles of dark-matter haloes. A hypothetical galaxy catalogue depends on (i) the efficiency of galaxy formation, as manifested by the halo occupation number -- the number of galaxies brighter than some sample limit contained in a halo of a given mass; (ii) the location of these galaxies within their halo. The first factor is constrained by the empirical luminosity function of groups. For the second factor, we assume that one galaxy marks the halo centre, with any remaining galaxies acting as satellites that trace the halo mass. These simple assumptions amount to a recipe for non-local bias, in which the probability of finding a galaxy is not a simple function of its local mass density. We have applied this prescription to some CDM models of current interest, and find that the predictions are close to the observed galaxy correlations for a flat $\\Omega=0.3$ model ($\\Lambda$CDM), but not for an $\\Omega=1$ model with the same power spectrum ($\\tau$CDM). This is an inevitable consequence of cluster normalization for the power spectra: cluster-scale haloes of given mass have smaller core radii for high $\\Omega$, and hence display enhanced small-scale clustering. Finally, the pairwise velocity dispersion of galaxies in the $\\Lambda$CDM model is lower than that of the mass, allowing cluster-normalized models to yield a realistic Mach number for the peculiar velocity field. This is largely due to the strong variation of galaxy-formation efficiency with halo mass that is required in this model.

J. A. Peacock; R. E. Smith

2000-06-30T23:59:59.000Z

62

MODIFIED GRAVITY SPINS UP GALACTIC HALOS  

SciTech Connect (OSTI)

We investigate the effect of modified gravity on the specific angular momentum of galactic halos by analyzing the halo catalogs at z = 0 from high-resolution N-body simulations for a f(R) gravity model that meets the solar-system constraint. It is shown that the galactic halos in the f(R) gravity model tend to acquire significantly higher specific angular momentum than those in the standard {Lambda}CDM model. The largest difference in the specific angular momentum distribution between these two models occurs for the case of isolated galactic halos with mass less than 10{sup 11} h {sup -1} M {sub Sun }, which are likely least shielded by the chameleon screening mechanism. As the specific angular momentum of galactic halos is rather insensitive to other cosmological parameters, it can in principle be an independent discriminator of modified gravity. We speculate a possibility of using the relative abundance of low surface brightness galaxies (LSBGs) as a test of general relativity given that the formation of the LSBGs occurs in fast spinning dark halos.

Lee, Jounghun [Astronomy Program, Department of Physics and Astronomy, FPRD, Seoul National University, Seoul 151-747 (Korea, Republic of)] [Astronomy Program, Department of Physics and Astronomy, FPRD, Seoul National University, Seoul 151-747 (Korea, Republic of); Zhao, Gong-Bo [National Astronomy Observatories, Chinese Academy of Science, Beijing 100012 (China)] [National Astronomy Observatories, Chinese Academy of Science, Beijing 100012 (China); Li, Baojiu [Institute of Computational Cosmology, Department of Physics, Durham University, Durham DH1 3LE (United Kingdom)] [Institute of Computational Cosmology, Department of Physics, Durham University, Durham DH1 3LE (United Kingdom); Koyama, Kazuya, E-mail: jounghun@astro.snu.ac.kr [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom)] [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom)

2013-01-20T23:59:59.000Z

63

Halo Formation in Warm Dark Matter Models  

E-Print Network [OSTI]

Discrepancies have emerged between the predictions of standard cold dark matter (CDM) theory and observations of clustering on sub-galactic scales. Warm dark matter (WDM) is a simple modification of CDM in which the dark matter particles have initial velocities due either to their having decoupled as thermal relics, or having been formed via non-equilibrium decay. We investigate the nonlinear gravitational clustering of WDM with a high resolution N-body code, and identify a number of distinctive observational signatures. Relative to CDM, halo concentrations and core densities are lowered, core radii are increased, and large halos emerge with far fewer low mass satellites. The number of small halos is suppressed, and those present are formed by `top down' fragmentation of caustics, as part of a `cosmic web' connecting massive halos. Few small halos form outside this web. If we identify small halos with dwarf galaxies, their number, spatial distribution, and formation epoch appear in better agreement with the observations for WDM than they are for CDM.

Paul Bode; Jeremiah P. Ostriker; Neil Turok

2001-05-29T23:59:59.000Z

64

Analysis of Halogen-Mercury Reactions in Flue Gas  

SciTech Connect (OSTI)

Oxidized mercury species may be formed in combustion systems through gas-phase reactions between elemental mercury and halogens, such as chorine or bromine. This study examines how bromine species affect mercury oxidation in the gas phase and examines the effects of mixtures of bromine and chlorine on extents of oxidation. Experiments were conducted in a bench-scale, laminar flow, methane-fired (300 W), quartz-lined reactor in which gas composition (HCl, HBr, NO{sub x}, SO{sub 2}) and temperature profile were varied. In the experiments, the post-combustion gases were quenched from flame temperatures to about 350 C, and then speciated mercury was measured using a wet conditioning system and continuous emissions monitor (CEM). Supporting kinetic calculations were performed and compared with measured levels of oxidation. A significant portion of this report is devoted to sample conditioning as part of the mercury analysis system. In combustion systems with significant amounts of Br{sub 2} in the flue gas, the impinger solutions used to speciate mercury may be biased and care must be taken in interpreting mercury oxidation results. The stannous chloride solution used in the CEM conditioning system to convert all mercury to total mercury did not provide complete conversion of oxidized mercury to elemental, when bromine was added to the combustion system, resulting in a low bias for the total mercury measurement. The use of a hydroxylamine hydrochloride and sodium hydroxide solution instead of stannous chloride showed a significant improvement in the measurement of total mercury. Bromine was shown to be much more effective in the post-flame, homogeneous oxidation of mercury than chlorine, on an equivalent molar basis. Addition of NO to the flame (up to 400 ppmv) had no impact on mercury oxidation by chlorine or bromine. Addition of SO{sub 2} had no effect on mercury oxidation by chlorine at SO{sub 2} concentrations below about 400 ppmv; some increase in mercury oxidation was observed at SO{sub 2} concentrations of 400 ppmv and higher. In contrast, SO{sub 2} concentrations as low as 50 ppmv significantly reduced mercury oxidation by bromine, this reduction could be due to both gas and liquid phase interactions between SO{sub 2} and oxidized mercury species. The simultaneous presence of chlorine and bromine in the flue gas resulted in a slight increase in mercury oxidation above that obtained with bromine alone, the extent of the observed increase is proportional to the chlorine concentration. The results of this study can be used to understand the relative importance of gas-phase mercury oxidation by bromine and chlorine in combustion systems. Two temperature profiles were tested: a low quench (210 K/s) and a high quench (440 K/s). For chlorine the effects of quench rate were slight and hard to characterize with confidence. Oxidation with bromine proved sensitive to quench rate with significantly more oxidation at the lower rate. The data generated in this program are the first homogeneous laboratory-scale data on bromine-induced oxidation of mercury in a combustion system. Five Hg-Cl and three Hg-Br mechanisms, some published and others under development, were evaluated and compared to the new data. The Hg-halogen mechanisms were combined with submechanisms from Reaction Engineering International for NO{sub x}, SO{sub x}, and hydrocarbons. The homogeneous kinetics under-predicted the levels of mercury oxidation observed in full-scale systems. This shortcoming can be corrected by including heterogeneous kinetics in the model calculations.

Paula Buitrago; Geoffrey Silcox; Constance Senior; Brydger Van Otten

2010-01-01T23:59:59.000Z

65

Process for removing halogenated aliphatic and aromatic compounds from petroleum products  

DOE Patents [OSTI]

A process for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contacting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible compound, such as, water or a polyhydroxy compound, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of water or polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the water or polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds and the low polar or nonpolar solvent are separated by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered from recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced.

Googin, John M. (Oak Ridge, TN); Napier, John M. (Oak Ridge, TN); Travaglini, Michael A. (Oliver Springs, TN)

1983-01-01T23:59:59.000Z

66

Process for removing halogenated aliphatic and aromatic compounds from petroleum products  

DOE Patents [OSTI]

A process is described for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contacting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible compound, such as, water or a polyhydroxy compound, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of water or polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the water or polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds and the low polar or nonpolar solvent are separated by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered from recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 1 fig.

Googin, J.M.; Napier, J.M.; Travaglini, M.A.

1983-09-20T23:59:59.000Z

67

Red Galaxy Growth and the Halo Occupation Distribution  

E-Print Network [OSTI]

We have traced the past 7 Gyr of red galaxy stellar mass growth within dark matter halos. We have determined the halo occupation distribution, which describes how galaxies reside within dark matter halos, using the observed luminosity function and clustering of 40,696 0.2red galaxies in Bootes. Half of 10^{11.9} Msun/h halos host a red central galaxy, and this fraction increases with increasing halo mass. We do not observe any evolution of the relationship between red galaxy stellar mass and host halo mass, although we expect both galaxy stellar masses and halo masses to evolve over cosmic time. We find that the stellar mass contained within the red population has doubled since z=1, with the stellar mass within red satellite galaxies tripling over this redshift range. In cluster mass halos most of the stellar mass resides within satellite galaxies and the intra-cluster light, with a minority of the stellar mass residing within central galaxies. The stellar masses of the most luminous red central galaxies are proportional to halo mass to the power of a third. We thus conclude that halo mergers do not always lead to rapid growth of central galaxies. While very massive halos often double in mass over the past 7 Gyr, the stellar masses of their central galaxies typically grow by only 30%.

Michael J. I. Brown; Zheng Zheng; Martin White; Arjun Dey; Buell T. Jannuzi; Andrew J. Benson; Kate Brand; Mark Brodwin; Darren J. Croton

2008-04-15T23:59:59.000Z

68

Dynamics of the Disruption Halo Current Toroidal Asymmetry in NSTX  

SciTech Connect (OSTI)

This paper describes the dynamics of disruption halo current non-axisymmetries in the lower divertor of the National Spherical Torus Experiment [M. Ono, et al. Nuclear Fusion 40, 557 (2000)]. While. The halo currents typically have a strongly asymmetric structure where they enter the divertor floor, and this asymmetry has been observed to complete up to 7 toroidal revolutions over the duration of the halo current pulse. However, the rotation speed and toroidal extend of the asymmetry can vary significantly during the pulse. The rotation speed, halo current pulse duration, and total number of revolutions tend to be smaller in cases with large halo currents. The halo current pattern is observed to become toroidally symmetric at the end of the halo current pulse. It is proposed that this symmeterization is due to the loss of most or all of the closed field line geometry in the final phase of the vertical displacement event.

S.P. Gerhardt

2012-09-27T23:59:59.000Z

69

The Structure of Dark Matter Haloes in Dwarf Galaxies  

E-Print Network [OSTI]

Recent observations indicate that dark matter haloes have flat central density profiles. Cosmological simulations with non-baryonic dark matter predict however self similar haloes with central density cusps. This contradiction has lead to the conclusion that dark matter must be baryonic. Here it is shown that the dark matter haloes of dwarf spiral galaxies represent a one parameter family with self similar density profiles. The observed global halo parameters are coupled with each other through simple scaling relations which can be explained by the standard cold dark matter model if one assumes that all the haloes formed from density fluctuations with the same primordial amplitude. We find that the finite central halo densities correlate with the other global parameters. This result rules out scenarios where the flat halo cores formed subsequently through violent dynamical processes in the baryonic component. These cores instead provide important information on the origin and nature of dark matter in dwarf galaxies.

A. Burkert

1995-04-12T23:59:59.000Z

70

Diffuse gamma-rays from galactic halos  

E-Print Network [OSTI]

Here we review our current knowledge on diffuse gamma-rays from galactic halos. Estimates of the relative contribution of the various emission processes at low and high latitudes are compared to the data over 6 decades in energy. The observed spectral shape differs from what was expected, especially at ver low and very high energies. In the latter case, above 1 GeV, the sky emission related to gas exceeds the expected pi^0 decay spectrum. At energies below 1 MeV the relatively high gamma-ray intensity indicates at high density of nearly relativistic electrons which would have a strong influence on the energy and ionisation balance of the interstellar medium. Given the EGRET results for the Magellanic Clouds the gamma-ray emissivity in the outer halo is probably small, so that a substantial amount of baryonic dark matter may be hidden at 20-50 kpc radius without inducing observable gamma-ray emission.

M. Pohl

1996-03-12T23:59:59.000Z

71

MODELING OBSERVATIONAL CONSTRAINTS FOR DARK MATTER HALOS  

SciTech Connect (OSTI)

Observations show that the underlying rotation curves at intermediate radii in spiral and low-surface-brightness galaxies are nearly universal. Further, in these same galaxies, the product of the central density and the core radius ({rho}{sub 0} r{sub 0}) is constant. An empirically motivated model for dark matter halos that incorporates these observational constraints is presented and shown to be in accord with the observations. A model fit to the observations of the galaxy cluster A611 shows that {rho}{sub 0} r{sub 0} for the dark matter halo in this more massive structure is larger by a factor of {approx}20 over that assumed for the galaxies. The model maintains the successful Navarro-Frenk-White form in the outer regions, although the well-defined differences in the inner regions suggest that modifications to the standard cold dark matter picture are required.

Hartwick, F. D. A. [Department of Physics and Astronomy, University of Victoria, Victoria, BC V8W 3P6 (Canada)

2012-12-01T23:59:59.000Z

72

The dependence on environment of Cold Dark Matter Halo properties  

E-Print Network [OSTI]

High-resolution LCDM cosmological N-body simulations are used to study the properties of galaxy-size dark halos in different environments (cluster, void, and "field"). Halos in clusters and their surroundings have a median spin parameter ~1.3 times lower, and tend to be more spherical and to have less aligned internal angular momentum than halos in voids and the field. For halos in clusters the concentration parameters decrease on average with mass with a slope of ~0.1; for halos in voids these concentrations do not change with mass. For masses environments. At z=1, the differences in the halo properties with environment almost dissapear, suggesting this that the differences were stablished mainly after z~1. The halos in clusters undergo more dramatic changes than those in the field or the voids. The differences with environment are owing to (i) the dependence of halo formation time on environment, and (ii) local effects as tidal stripping and the tumultuos histories that halos suffer in high-density regions. We calculate seminumerical models of disk galaxy evolution in halos with the properties found for the different environments. For a given disk mass, the galaxy disks have higher surface density, larger Vd,max and secular bulge-to-disk ratio, lower gas fraction, and are redder as one goes from cluster to void environments, in rough agreement with observations. (abridged)

V. Avila-Reese; P. Colin; S. Gottloeber; C. Firmani; C. Maulbetsch

2005-08-01T23:59:59.000Z

73

Halo mass distribution reconstruction across the cosmic web  

E-Print Network [OSTI]

We study the relation between halo mass and its environment from a probabilistic perspective. We find that halo mass depends not only on local dark matter density, but also on non-local quantities such as the cosmic web environment and the halo-exclusion effect. Given these accurate relations, we have developed the HADRON-code (Halo mAss Distribution ReconstructiON), a technique which permits us to assign halo masses to a distribution of haloes in three-dimensional space. This can be applied to the fast production of mock galaxy catalogues, by assigning halo masses, and reproducing accurately the bias for different mass cuts. The resulting clustering of the halo populations agree well with that drawn from the BigMultiDark $N$-body simulation: the power spectra are within 1-$\\sigma$ up to scales of $k=0.2\\,h\\,{\\rm Mpc}^{-1}$, when using augmented Lagrangian perturbation theory based mock catalogues. Only the most massive haloes show a larger deviation. For these, we find evidence of the halo-exclusion effect. ...

Zhao, Cheng; Chuang, Chia-Hsun; Prada, Francisco; Yepes, Gustavo; Tao, Charling

2015-01-01T23:59:59.000Z

74

THE SPHERICALIZATION OF DARK MATTER HALOS BY GALAXY DISKS  

SciTech Connect (OSTI)

Cosmological simulations indicate that cold dark matter (CDM) halos should be triaxial. Validating this theoretical prediction is, however, less than straightforward because the assembly of galaxies is expected to modify halo shapes and to render them more axisymmetric. We use a suite of N-body simulations to quantitatively investigate the effect of the growth of a central disk galaxy on the shape of triaxial dark matter halos. In most circumstances, the halo responds to the presence of the disk by becoming more spherical. The net effect depends weakly on the timescale of the disk assembly but noticeably on the orientation of the disk relative to the halo principal axes, and it is maximal when the disk symmetry axis is aligned with the major axis of the halo. The effect depends most sensitively on the overall gravitational importance of the disk. Our results indicate that exponential disks whose contribution peaks at less than {approx}50% of their circular velocity are unable to noticeably modify the shape of the gravitational potential of their surrounding halos. Many dwarf and low surface brightness galaxies are expected to be in this regime, and therefore their detailed kinematics could be used to probe halo triaxiality, one of the basic predictions of the CDM paradigm. We argue that the complex disk kinematics of the dwarf galaxy NGC 2976 might be the reflection of a triaxial halo. Such signatures of halo triaxiality should be common in galaxies where the luminous component is subdominant.

Kazantzidis, Stelios [Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States); Abadi, Mario G. [Instituto de Astronomia Teorica y Experimental (IATE), Observatorio Astronomico de Cordoba and CONICET, Laprida 854 X5000BGR Cordoba (Argentina); Navarro, Julio F., E-mail: stelios@mps.ohio-state.ed, E-mail: mario@oac.uncor.ed, E-mail: jfn@uvic.c [Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2 (Canada)

2010-09-01T23:59:59.000Z

75

The Halo Stars in NGC 5128. III: An Inner-Halo Field and the Metallicity Distribution  

E-Print Network [OSTI]

We present new HST/WFPC2 (V,I) photometry for the red-giant stars in NGC 5128 at a projected distance of 8 kpc from the galaxy center, which probe a mixture of its inner halo and outer bulge. The color-magnitude diagram shows an old red-giant branch which is even broader in color than our two previously studied outer-halo fields (at 21 and 31 kpc), with significant numbers of stars extending to Solar metallicity and higher. The peak frequency of the metallicity distribution function (MDF) is at [m/H] ~ -0.4, with even fewer metal-poor stars than in the outer-halo fields. We find that the main features of the halo MDF can be reproduced by a simple chemical evolution model in which early star formation goes on simultaneously with an initial stage of rapid infall of very metal-poor gas, after which the infall dies away exponentially. A comparison with the MDF for the NGC 5128 globular clusters indicates that there is a clear decrease of specific frequency $S_N$ (number of clusters per unit halo light) with increasing metallicity, from S_N ~ 4-8 at [Fe/H] -1. This trend may indicate that globular cluster formation efficiency is a strong function of the metallicity of the protocluster gas.

W. E. Harris; G. L. H. Harris

2002-04-26T23:59:59.000Z

76

Merger Rates of Dark-Matter Haloes  

E-Print Network [OSTI]

We derive analytic merger rates for dark-matter haloes within the framework of the Extended Press-Schechter (EPS) formalism. These rates become self-consistent within EPS once we realize that the typical merger in the limit of a small time-step involves more than two progenitors, contrary to the assumption of binary mergers adopted in earlier studies. We present a general method for computing merger rates that span the range of solutions permitted by the EPS conditional mass function, and focus on a specific solution that attempts to match the merger rates in N-body simulations. The corrected EPS merger rates are more accurate than the earlier estimates of Lacey & Cole, by ~20% for major mergers and by up to a factor of ~3 for minor mergers of mass ratio 1:10^4. Based on the revised merger rates, we provide a new algorithm for constructing Monte-Carlo EPS merger trees, that could be useful in Semi-Analytic Modeling. We provide analytic expressions and plot numerical results for several quantities that are very useful in studies of galaxy formation. This includes (a) the rate of mergers of a given mass ratio per given final halo, (b) the fraction of mass added by mergers to a halo, and (c) the rate of mergers per given main progenitor. The creation and destruction rates of haloes serve for a self-consistency check. Our method for computing merger rates can be applied to conditional mass functions beyond EPS, such as those obtained by the ellipsoidal collapse model or extracted from $N$-body simulations.

Eyal Neistein; Avishai Dekel

2008-05-22T23:59:59.000Z

77

Comparing halo bias from abundance and clustering  

E-Print Network [OSTI]

We model the abundance of haloes in the $\\sim(3 \\ \\text{Gpc}/h)^3$ volume of the MICE Grand Challenge simulation by fitting the universal mass function with an improved Jack-Knife error covariance estimator that matches theory predictions. We present unifying relations between different fitting models and new predictions for linear ($b_1$) and non-linear ($c_2$ and $c_3$) halo clustering bias. Different mass function fits show strong variations in their overall poor performance when including the low mass range ($M_h \\lesssim 3 \\ 10^{12} \\ M_{\\odot}/h$) in the analysis, which indicates noisy friends-of-friends halo detection given the MICE resolution ($m_p \\simeq 3 \\ 10^{10} \\ M_{\\odot}$/h). Together with fits from the literature we find an overall variance in the amplitudes of around $10%$ in the low mass and up to $50%$ in the high mass (galaxy cluster) range ($M_h > 10^{14} \\ M_{\\odot}/h$). These variations propagate into a $10%$ change in $b_1$ predictions and a $50%$ change in $c_2$ or $c_3$. Despite the...

Hoffmann, Kai; Gaztanaga, Enrique

2015-01-01T23:59:59.000Z

78

Low-Level Detections of Halogenated Volatile Organic Compounds in Groundwater  

E-Print Network [OSTI]

compounds; Groundwater management; Drinking water. Introduction Approximately one-half of the U and Hitt 2006 , or more complex process-based analyses utilizing groundwater models Eberts et al. 2005Low-Level Detections of Halogenated Volatile Organic Compounds in Groundwater: Use in Vulnerability

79

Mercury Lamps Recycling Fluorescent light-tubes, compact fluorescent bulbs, mercury and sodium vapor lamps, ultraviolet and  

E-Print Network [OSTI]

Mercury Lamps Recycling Fluorescent light-tubes, compact fluorescent bulbs, mercury and sodium vapor lamps, ultraviolet and HID (high-intensity discharge) lamps and all other mercury containing labeled for shipment to a recycling plant for mercury, glass and aluminum recovery. The beneficial re

Baker, Chris I.

80

LED lamp or bulb with remote phosphor and diffuser configuration with enhanced scattering properties  

DOE Patents [OSTI]

An LED lamp or bulb is disclosed that comprises a light source, a heat sink structure and an optical cavity. The optical cavity comprises a phosphor carrier having a conversions material and arranged over an opening to the cavity. The phosphor carrier comprises a thermally conductive transparent material and is thermally coupled to the heat sink structure. An LED based light source is mounted in the optical cavity remote to the phosphor carrier with light from the light source passing through the phosphor carrier. A diffuser dome is included that is mounted over the optical cavity, with light from the optical cavity passing through the diffuser dome. The properties of the diffuser, such as geometry, scattering properties of the scattering layer, surface roughness or smoothness, and spatial distribution of the scattering layer properties may be used to control various lamp properties such as color uniformity and light intensity distribution as a function of viewing angle.

Tong, Tao; Le Toquin, Ronan; Keller, Bernd; Tarsa, Eric; Youmans, Mark; Lowes, Theodore; Medendorp, Jr., Nicholas W; Van De Ven, Antony; Negley, Gerald

2014-11-11T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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

COMPOSITION OF LOW-REDSHIFT HALO GAS  

SciTech Connect (OSTI)

Halo gas in low-z (z < 0.5) {>=}0.1 L{sub *} galaxies in high-resolution, large-scale cosmological hydrodynamic simulations is examined with respect to three components: cold, warm, and hot with temperatures of <10{sup 5}, 10{sup 5-6}, and >10{sup 6} K, respectively. Utilizing O VI {lambda}{lambda}1032, 1038 absorption lines, the warm component is compared to observations, and agreement is found with respect to the galaxy-O VI line correlation, the ratio of the O VI line incidence rate in blue to red galaxies, and the amount of O VI mass in star-forming galaxies. A detailed account of the sources of warm halo gas (stellar feedback heating, gravitational shock heating, and accretion from the intergalactic medium), inflowing and outflowing warm halo gas metallicity disparities, and their dependencies on galaxy types and environment is also presented. With the warm component securely anchored, our simulations make the following additional predictions. First, cold gas is the primary component in inner regions with its mass comprising 50% of all gas within galactocentric radius r = (30, 150) kpc in (red, blue) galaxies. Second, at r > (30, 200) kpc in (red, blue) galaxies the hot component becomes the majority. Third, the warm component is a perpetual minority, with its contribution peaking at {approx}30% at r = 100-300 kpc in blue galaxies and never exceeding 5% in red galaxies. The significant amount of cold gas in low-z early-type galaxies, which was found in simulations and in agreement with recent observations (Thom et al.), is intriguing, as is the dominance of hot gas at large radii in blue galaxies.

Cen Renyue, E-mail: cen@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Peyton Hall, Ivy Lane, Princeton, NJ 08544 (United States)

2013-06-20T23:59:59.000Z

82

Using Tidal Tails to Probe Dark Matter Halos  

E-Print Network [OSTI]

We use simulations of merging galaxies to explore the sensitivity of the morphology of tidal tails to variations of the halo mass distributions in the parent galaxies. Our goal is to constrain the mass of dark halos in well-known merging pairs. We concentrate on prograde encounters between equal mass galaxies which represent the best cases for creating tidal tails, but also look at systems with different relative orientations, orbital energies and mass ratios. As the mass and extent of the dark halo increase in the model galaxies, the resulting tidal tails become shorter and less massive, even under the most favorable conditions for producing these features. Our simulations imply that the observed merging galaxies with long tidal tails ($\\sim 50-100$ kpc) such as NGC 4038/39 (the Antennae) and NGC 7252 probably have halo:disk+bulge mass ratios less than 10:1. These results conflict with the favored values of the dark halo mass of the Milky Way derived from satellite kinematics and the timing argument which give a halo:disk+bulge mass ratio of $\\sim 30:1$. However, the lower bound of the estimated dark halo mass in the Milky Way (mass ratio $\\sim 10:1$) is still consistent with the inferred tidal tail galaxy masses. Our results also conflict with the expectations of $\\Omega=1$ cosmologies such as CDM which predict much more massive and extended dark halos.

John Dubinski; J. Christopher Mihos; Lars Hernquist

1995-09-04T23:59:59.000Z

83

Effectsof ice-crystal structure on halo formation: cirrus cloud  

E-Print Network [OSTI]

Effectsof ice-crystal structure on halo formation: cirrus cloud experimental and ray campaign, four 220halo-producing cirrus clouds were studied jointly from a ground- based polarization lidar of the aircraft, which collecteda total of 84slides byimpaction, preserving the ice crystals for later microscopic

Takano, Yoshihide

84

THE COSMOGRID SIMULATION: STATISTICAL PROPERTIES OF SMALL DARK MATTER HALOS  

SciTech Connect (OSTI)

We present the results of the ''Cosmogrid'' cosmological N-body simulation suites based on the concordance LCDM model. The Cosmogrid simulation was performed in a 30 Mpc box with 2048{sup 3} particles. The mass of each particle is 1.28 Multiplication-Sign 10{sup 5} M{sub Sun }, which is sufficient to resolve ultra-faint dwarfs. We found that the halo mass function shows good agreement with the Sheth and Tormen fitting function down to {approx}10{sup 7} M{sub Sun }. We have analyzed the spherically averaged density profiles of the three most massive halos which are of galaxy group size and contain at least 170 million particles. The slopes of these density profiles become shallower than -1 at the innermost radius. We also find a clear correlation of halo concentration with mass. The mass dependence of the concentration parameter cannot be expressed by a single power law, however a simple model based on the Press-Schechter theory proposed by Navarro et al. gives reasonable agreement with this dependence. The spin parameter does not show a correlation with the halo mass. The probability distribution functions for both concentration and spin are well fitted by the log-normal distribution for halos with the masses larger than {approx}10{sup 8} M{sub Sun }. The subhalo abundance depends on the halo mass. Galaxy-sized halos have 50% more subhalos than {approx}10{sup 11} M{sub Sun} halos have.

Ishiyama, Tomoaki [Center for Computational Science, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Rieder, Steven; Portegies Zwart, Simon [Sterrewacht Leiden, Leiden University, P.O. Box 9513, 2300-RA Leiden (Netherlands); Makino, Junichiro [Graduate School of Science and Engineering, Tokyo Institute of Technology (Japan); Groen, Derek [Centre for Computational Science, Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ (United Kingdom); Nitadori, Keigo [RIKEN Advanced Institute for Computational Science (Japan); De Laat, Cees [Section System and Network Engineering, University of Amsterdam, Amsterdam (Netherlands); McMillan, Stephen [Department of Physics, Drexel University, Philadelphia, PA 19104 (United States); Hiraki, Kei [Department of Creative Informatics, Graduate School of Information Science and Technology, the University of Tokyo (Japan); Harfst, Stefan, E-mail: ishiyama@ccs.tsukuba.ac.jp [Center for Astronomy and Astrophysics, Technical University Berlin, Hardenbergstr. 36, D-10623 Berlin (Germany)

2013-04-20T23:59:59.000Z

85

MACHO (MAssive Compact Halo Objects) Data  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

The primary aim of the MACHO Project is to test the hypothesis that a significant fraction of the dark matter in the halo of the Milky Way is made up of objects like brown dwarfs or planets: these objects have come to be known as MACHOs, for MAssive Compact Halo Objects. The signature of these objects is the occasional amplification of the light from extragalactic stars by the gravitational lens effect. The amplification can be large, but events are extremely rare: it is necessary to monitor photometrically several million stars for a period of years in order to obtain a useful detection rate. For this purpose MACHO has a two channel system that employs eight CCDs, mounted on the 50 inch telescope at Mt. Stromlo. The high data rate (several GBytes per night) is accommodated by custom electronics and on-line data reduction. The Project has taken more than 27,000 images with this system since June 1992. Analysis of a subset of these data has yielded databases containing light curves in two colors for 8 million stars in the LMC and 10 million in the bulge of the Milky Way. A search for microlensing has turned up four candidates toward the Large Magellanic Cloud and 45 toward the Galactic Bulge. The web page for data provides links to MACHO Project data portals and various specialized interfaces for viewing or searching the data. (Specialized Interface)

86

Spin alignment of dark matter haloes in filaments and walls  

E-Print Network [OSTI]

The MMF technique is used to segment the cosmic web as seen in a cosmological N-body simulation into wall-like and filament-like structures. We find that the spins and shapes of dark matter haloes are significantly correlated with each other and with the orientation of their host structures. The shape orientation is such that the halo minor axes tend to lie perpendicular to the host structure, be it a wall or filament. The orientation of the halo spin vector is mass dependent. Low mass haloes in walls and filaments have a tendency to have their spins oriented within the parent structure, while higher mass haloes in filaments have spins that tend to lie perpendicular to the parent structure.

Miguel A. Aragn-Calvo; Rien van de Weygaert; Bernard J. T. Jones; J. M. Thijs van der Hulst

2006-10-09T23:59:59.000Z

87

The alignment of dark matter halos with the cosmic web  

E-Print Network [OSTI]

We investigate the orientation of the axes and angular momentum of dark matter halos with respect to their neighboring voids using high resolution N-body cosmological simulations. We find that the minor axis of halos tends to be aligned along the line joining the halo with the center of the void, and that the major axis is perpendicular to this line. However, we find that the angular momentum of halos does not have any particular orientation. These results may provide information about the mechanisms whereby the large-scale structure of the Universe affects galaxy formation and cast light upon the issue of the orientation of galaxy disks with respect to their host halos.

Santiago G. Patiri; Antonio J. Cuesta; Francisco Prada; Juan Betancort-Rijo; Anatoly Klypin

2006-10-23T23:59:59.000Z

88

SUBSTRUCTURE IN THE STELLAR HALOS OF THE AQUARIUS SIMULATIONS  

SciTech Connect (OSTI)

We characterize the substructure in the simulated stellar halos of Cooper et al. which were formed by the disruption of satellite galaxies within the cosmological N-body simulations of galactic halos of the Aquarius project. These stellar halos exhibit a wealth of tidal features: broad overdensities and very narrow faint streams akin to those observed around the Milky Way. The substructures are distributed anisotropically on the sky, a characteristic that should become apparent in the next generation of photometric surveys. The normalized RMS of the density of stars on the sky appears to be systematically larger for our halos compared with the value estimated for the Milky Way from main-sequence turnoff stars in the Sloan Digital Sky Survey. We show that this is likely to be due in part to contamination by faint QSOs and redder main-sequence stars, and might suggest that {approx}10% of the Milky Way halo stars have formed in situ.

Helmi, Amina [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen (Netherlands); Cooper, A. P.; Cole, S.; Frenk, C. S. [Institute for Computational Cosmology, Department of Physics, University of Durham, South Road, Durham DH1 3LE (United Kingdom); White, S. D. M. [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Navarro, J. F., E-mail: ahelmi@astro.rug.nl [Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 5C2 (Canada)

2011-05-20T23:59:59.000Z

89

Impending U.S. lighting standards will boost market for halogen-infrared lamps: New product line expanding  

SciTech Connect (OSTI)

Many of the incandescent floodlights and spotlights manufactured today will not meet lighting efficiency standards taking effect in the US in 1995. As these models cease production, demand will grow for higher efficiency units to fill this huge market, which now totals about 100 million lamps per year. One prime contender is a new class of halogen lamps that use a spectrally selective coating to reflect heat back onto the filament, reducing the amount of electricity needed to generate light. GE Lighting`s Halogen-IR line is the only series of such lamps currently available to replace the conventional floodlights and spotlights that will be banned by the new standards. Other manufacturers may adopt the technology, however, and the Japanese producer Ushio already sells in the US a line of smaller halogen lamps with a similar heat-reflective coating. In terms of efficacy and lifetime, Halogen-IR lamps out perform standard incandescents and standard halogens, but fall far short of fluorescent, metal halide, and high-pressure sodium sources. These other lighting systems are more appropriate and cost-effective than incandescents for many ambient lighting applications. For accent lighting and other tasks that are best suited to incandescent lighting, however, the Halogen-IR lamp is often a superior choice.

Sardinsky, R.; Shepard, M.

1993-12-31T23:59:59.000Z

90

Method of increments for the halogen molecular crystals: Cl, Br, and I  

SciTech Connect (OSTI)

Method of increments (MI) calculations reveal the n-body correlation contributions to binding in solid chlorine, bromine, and iodine. Secondary binding contributions as well as d-correlation energies are estimated and compared between each solid halogen. We illustrate that binding is entirely determined by two-body correlation effects, which account for >80% of the total correlation energy. One-body, three-body, and exchange contributions are repulsive. Using density-fitting (DF) local coupled-cluster singles, doubles, and perturbative triples for incremental calculations, we obtain excellent agreement with the experimental cohesive energies. MI results from DF local second-order Mller-Plesset perturbation (LMP2) yield considerably over-bound cohesive energies. Comparative calculations with density functional theory and periodic LMP2 method are also shown to be less accurate for the solid halogens.

Steenbergen, Krista G. [Physikalische und Theoretische Chemie, Freie Universitt Berlin, Takustr. 3, 14195 Berlin (Germany); MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington, P.O. Box 600, Wellington 6012 (New Zealand); Gaston, Nicola [MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington, P.O. Box 600, Wellington 6012 (New Zealand); Mller, Carsten; Paulus, Beate [Physikalische und Theoretische Chemie, Freie Universitt Berlin, Takustr. 3, 14195 Berlin (Germany)

2014-09-28T23:59:59.000Z

91

The chemistry of halogens on diamond: effects on growth and electron emission  

SciTech Connect (OSTI)

Diamond growth using halogenated precursors was studied in several diamond growth reactors. In a conventionao plasma reactor, diamond growth using the following gas mixtures was studied: CF{sub 4}/H{sub 2}, CH{sub 4}/H{sub 2}, CH{sub 3}F/H{sub 2}, and CH{sub 3}CL/H{sub 2}. Both the diamond growth measurements demonstrated ineffective transport of halogen radicals to the diamond surface during the growth process. In order to transport radical halogen species to the diamond surface during growth, a flow-tube reactor was constructed which minimized gas phase reactions. Also, the flow-tube reactor enabled pulsed gs transport to the diamond surface by fast-acting valves. Molecular beam mass spectroscopy was used to find condition which resulted in atomic hydrogen and/or atomic fluorine transport to the growing diamond surface. Although such conditions were found, they required very low pressures (0.5 Torr and below); these low pressures produce radical fluxes which are too low to sustain a reasonable diamond growth rate. The sequential reactor at Stanford was modified to add a halogen-growth step to the conventinoal atomic hydrogen/atomic carbon diamond growth cycle. Since the atomic fluorine, hydrogen and carbon environments are independent in the sequential reactor, the effect of fluorine on diamond growth could be studied independently of gas phase reactions. Although the diamond growth rate was increased by the use of fluorine, the film quality was seen to deteriorate as well as the substrate surface. Moreover, materials incompatibilities with fluorine significantly limited the use of fluorine in this reactor. A diamond growth model incorporating both gas phase and surface reactions was developed for the halocarbon system concurrent with the film growth efforts. In this report, we review the results of the growth experiments, the modeling, and additional experiments done to understand fluorine with diamond surfaces.

Hsu, W.L.; Pan, L.S.; Brown, L.A. [Sandia National Labs., Livermore, CA (United States)] [and others

1997-02-01T23:59:59.000Z

92

THE OVERDENSITY AND MASSES OF THE FRIENDS-OF-FRIENDS HALOS AND UNIVERSALITY OF HALO MASS FUNCTION  

SciTech Connect (OSTI)

The friends-of-friends algorithm (hereafter FOF) is a percolation algorithm which is routinely used to identify dark matter halos from N-body simulations. We use results from percolation theory to show that the boundary of FOF halos does not correspond to a single density threshold but to a range of densities close to a critical value that depends upon the linking length parameter, b. We show that for the commonly used choice of b = 0.2, this critical density is equal to 81.62 times the mean matter density. Consequently, halos identified by the FOF algorithm enclose an average overdensity which depends on their density profile (concentration) and therefore changes with halo mass, contrary to the popular belief that the average overdensity is {approx}180. We derive an analytical expression for the overdensity as a function of the linking length parameter b and the concentration of the halo. Results of tests carried out using simulated and actual FOF halos identified in cosmological simulations show excellent agreement with our analytical prediction. We also find that the mass of the halo that the FOF algorithm selects crucially depends upon mass resolution. We find a percolation-theory-motivated formula that is able to accurately correct for the dependence on number of particles for the mock realizations of spherical and triaxial Navarro-Frenk-White halos. However, we show that this correction breaks down when applied to the real cosmological FOF halos due to the presence of substructures. Given that abundance of substructure depends on redshift and cosmology, we expect that the resolution effects due to substructure on the FOF mass and halo mass function will also depend on redshift and cosmology and will be difficult to correct for in general. Finally, we discuss the implications of our results for the universality of the mass function.

More, Surhud; Kravtsov, Andrey V. [Kavli Institute for Cosmological Physics and Enrico Fermi Institute, University of Chicago, Chicago, IL 60637 (United States); Dalal, Neal [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 3H8 (Canada); Gottloeber, Stefan, E-mail: surhud@kicp.uchicago.edu [Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam (Germany)

2011-07-01T23:59:59.000Z

93

Photofragmentation spectra of halogenated methanes in the VUV photon energy range  

SciTech Connect (OSTI)

In this paper an investigation of the photofragmentation of dihalomethanes CH{sub 2}X{sub 2} (X = F, Cl, Br, I) and chlorinated methanes (CH{sub n}Cl{sub 4?n} with n = 03) with VUV helium, neon, and argon discharge lamps is reported and the role played by the different halogen atoms is discussed. Halogenated methanes are a class of molecules used in several fields of chemistry and the study of their physical and chemical proprieties is of fundamental interest. In particular their photodissociation and photoionization are of great importance since the decomposition of these compounds in the atmosphere strongly affects the environment. The results of the present work show that the halogen-loss is the predominant fragmentation channel for these molecules in the VUV photon energy range and confirm their role as reservoir of chlorine, bromine, and iodine atoms in the atmosphere. Moreover, the results highlight the peculiar feature of CH{sub 2}F{sub 2} as a source of both fluorine and hydrogen atoms and the characteristic formation of I{sub 2}{sup +} and CH{sub 2}{sup +} ions from the photofragmentation of the CH{sub 2}I{sub 2} molecule.

Cartoni, Antonella, E-mail: antonella.cartoni@uniroma1.it [Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Universit di Roma, P.le Aldo Moro 5, Roma 00185 (Italy)] [Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Universit di Roma, P.le Aldo Moro 5, Roma 00185 (Italy); Bolognesi, Paola; Fainelli, Ettore; Avaldi, Lorenzo [CNR-IMIP, Area della Ricerca di Roma 1, Monterotondo Scalo (Rm) 00015 (Italy)] [CNR-IMIP, Area della Ricerca di Roma 1, Monterotondo Scalo (Rm) 00015 (Italy)

2014-05-14T23:59:59.000Z

94

Spectral irradiance model for tungsten halogen lamps in 340-850 nm wavelength range  

SciTech Connect (OSTI)

We have developed a physical model for the spectral irradiance of 1 kW tungsten halogen incandescent lamps for the wavelength range 340-850 nm. The model consists of the Planck's radiation law, published values for the emissivity of tungsten, and a residual spectral correction function taking into account unknown factors of the lamp. The correction function was determined by measuring the spectra of a 1000 W, quartz-halogen, tungsten coiled filament (FEL) lamp at different temperatures. The new model was tested with lamps of types FEL and 1000 W, 120 V quartz halogen (DXW). Comparisons with measurements of two national standards laboratories indicate that the model can account for the spectral irradiance values of lamps with an agreement better than 1% throughout the spectral region studied. We further demonstrate that the spectral irradiance of a lamp can be predicted with an expanded uncertainty of 2.6% if the color temperature and illuminance values for the lamp are known with expanded uncertainties of 20 K and 2%, respectively. In addition, it is suggested that the spectral irradiance may be derived from resistance measurements of the filament with lamp on and off.

Ojanen, Maija; Kaerhae, Petri; Ikonen, Erkki

2010-02-10T23:59:59.000Z

95

Visualization of nitric oxide production in the mouse main olfactory bulb by a cell-trappable copper(II) fluorescent probe  

E-Print Network [OSTI]

We report the visualization of NO production using fluorescence in tissue slices of the mouse main olfactory bulb. This discovery was possible through the use of a novel, cell-trappable probe for intracellular nitric oxide ...

McQuade, Lindsey E.

96

Dynamical insight into dark-matter haloes  

E-Print Network [OSTI]

We investigate, using the spherical Jeans equation, self-gravitating dynamical equilibria satisfying a relation rho/sigma_r^3 propto r^-alpha, which holds for simulated dark-matter haloes over their whole resolved radial range. Considering first the case of velocity isotropy, we find that this problem has only one solution with realistic density profile, which occurs only for a critical value of alpha_crit = 35/18 ~= 1.94, which is consistent with the empirical value of 1.9+/-0.05. We extend our analysis in two ways: first we introduce a parameter epsilon to allow for a more general relation rho/\\sigma_r^epsilon propto r^-alpha; second we consider velocity anisotropy. If we assume beta(r) := 1- sigma_theta^2 / sigma_r^2 to be linearly related to the logarithmic density slope gamma(r) := -dln(rho)/dln(r), which is in agreement with simulations, the problem remains analytically tractable and is equivalent to the simpler isotropic case: there exists only one physical solution, which occurs at a critical alpha value. Remarkably, this value of alpha and the density and velocity-dispersion profiles depend only on epsilon and the value beta_0 := beta(r=0), but not on the slope of the linear beta-gamma relation. For epsilon=3, alpha_crit = 35/18 - 2beta_0/9 and the resulting density profile is fully analytic (as are the velocity dispersion and circular speed) with an inner cusp rho propto r^{-(7+10beta_0)/9} and a very smooth transition to a steeper outer power-law asymptote. These models are in excellent agreement with the density, velocity-dispersion and anisotropy profiles of simulated dark-matter haloes over their full resolved radial range. If epsilon=3 is a universal constant, some scatter in beta_0 ~= 0 may account for some diversity in the density profiles. (ABRIDGED)

Walter Dehnen; Dean McLaughlin

2005-06-22T23:59:59.000Z

97

Galactosynthesis: Halo Histories, Star Formation, and Disks  

E-Print Network [OSTI]

We investigate the effects of a variety of ingredients that must enter into a realistic model for disk-galaxy formation, focusing primarily on the Tully-Fisher (TF) relation and its scatter in several wavebands. Our main findings are: (a) the slope, normalization, and scatter of the TF relation across various wavebands is determined {\\em both} by halo properties and star formation in the disk; (b) TF scatter owes primarily to the spread in formation redshifts. The scatter can be measurably reduced by chemical evolution, and also in some cases by the weak anti-correlation between peak height and spin; (c) multi-wavelength constraints can be important in distinguishing between models which appear to fit the TF relation in I or K; (d) successful models seem to require that the bulk of disk formation cannot occur too early (z>2) or too late (z<0.5), and are inconsistent with high values of $\\Omega_0$; (e) a realistic model with the above ingredients can reasonably reproduce the observed z=0 TF relation in {\\em all} bands (B, R, I, and K). It can also account for the z=1 B-band TF relation and yield rough agreement with the local B and K luminosity functions and B-band surface-brightness--magnitude relation. The remarkable agreement with observations suggests that the amount of gas that is expelled or poured into a disk galaxy must be small, and that the specific angular momentum of the baryons must roughly equal that of the halo; there is little room for angular momentum transfer. In an appendix we present analytic fits to stellar-population synthesis models.

Ari Buchalter; Raul Jimenez; Marc Kamionkowski

2000-06-01T23:59:59.000Z

98

ACCURATE MASS ESTIMATORS FOR NAVARRO-FRENK-WHITE HALOS  

SciTech Connect (OSTI)

We consider the problem of estimating the virial mass of a dark halo from the positions and velocities of a tracer population. Although a number of general tools are available, more progress can be made if we are able to specify the functional form of the halo potential (although not its normalization). Here, we consider the Navarro-Frenk-White halo and develop two simple estimators. We demonstrate their effectiveness against numerical simulations and use them to provide new mass estimates of Carina, Fornax, Sculptor, and Sextans dwarf spheroidal galaxies.

Evans, N. W.; Deason, A. J. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); An, J., E-mail: nwe@ast.cam.ac.uk, E-mail: ajd75@cam.ac.uk, E-mail: jinan@nao.cas.cn [National Astronomical Observatories, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing 100012 (China)

2011-04-01T23:59:59.000Z

99

EFFECT OF DARK MATTER HALO SUBSTRUCTURES ON GALAXY ROTATION CURVES  

SciTech Connect (OSTI)

In this paper, the effect of halo substructures on galaxy rotation curves is investigated using a simple model of dark matter clustering. A dark matter halo density profile is developed based only on the scale-free nature of clustering that leads to a statistically self-similar distribution of the substructures at the galactic scale. A semi-analytical method is used to derive rotation curves for such a clumpy dark matter density profile. It is found that the halo substructures significantly affect the galaxy velocity field. Based on the fractal geometry of the halo, this self-consistent model predicts a Navarro-Frenk-White-like rotation curve and a scale-free power spectrum of the rotation velocity fluctuations.

Roy, Nirupam, E-mail: nroy@aoc.nrao.ed [NRAO, P.O. Box O, 1003 Lopezville Road, Socorro, NM 87801 (United States)

2010-11-01T23:59:59.000Z

100

Cores and cusps in warm dark matter halos  

SciTech Connect (OSTI)

The apparent presence of large core radii in Low Surface Brightness galaxies has been claimed as evidence in favor of warm dark matter. Here we show that WDM halos do not have cores that are large fractions of the halo size: typically, r{sub core}/r{sub 200}?<10{sup ?3}. This suggests an astrophysical origin for the large cores observed in these galaxies, as has been argued by other authors.

Villaescusa-Navarro, Francisco [IFIC, Universidad de Valencia-CSIC, E-46071, Valencia (Spain); Dalal, Neal, E-mail: villa@ific.uv.es, E-mail: neal@cita.utoronto.ca [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George St., Toronto, ON, M5S3H8 (Canada)

2011-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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

Possible existence of wormholes in the central regions of halos  

E-Print Network [OSTI]

An earlier study [Rahaman et al. (2014) & Kuhfittig (2014)] has demonstrated the possible existence of wormholes in the outer regions of the galactic halo, based on the Navarro-Frenk-White (NFW) density profile. This paper uses the Universal Rotation Curve (URC) dark matter model to obtain analogous results for the central parts of the halo. This result is an important compliment to the earlier result, thereby confirming the possible existence of wormholes in most of the spiral galaxies.

Farook Rahaman; P. Salucci; P. K. F. Kuhfittig; Saibal Ray; Mosiur Rahaman

2015-01-05T23:59:59.000Z

102

DUAL HALOS AND FORMATION OF EARLY-TYPE GALAXIES  

SciTech Connect (OSTI)

We present a determination of the two-dimensional shape parameters of the blue and red globular cluster systems (GCSs) in a large number of elliptical galaxies and lenticular galaxies (early-type galaxies, called ETGs). We use a homogeneous data set of the globular clusters in 23 ETGs obtained from the HST/ACS Virgo Cluster Survey. The position angles of both blue and red GCSs show a correlation with those of the stellar light distribution, showing that the major axes of the GCSs are well aligned with those of their host galaxies. However, the shapes of the red GCSs show a tight correlation with the stellar light distribution as well as with the rotation property of their host galaxies, while the shapes of the blue GCSs do much less. These provide clear geometric evidence that the origins of the blue and red globular clusters are distinct and that ETGs may have dual halos: a blue (metal-poor) halo and a red (metal-rich) halo. These two halos show significant differences in metallicity, structure, and kinematics, indicating that they are formed in two distinguishable ways. The red halos might have formed via dissipational processes with rotation, while the blue halos are through accretion.

Park, Hong Soo; Lee, Myung Gyoon, E-mail: hspark@astro.snu.ac.kr, E-mail: mglee@astro.snu.ac.kr [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul (Korea, Republic of)

2013-08-20T23:59:59.000Z

103

Process for removing halogenated aliphatic and aromatic compounds from petroleum products. [Polychlorinated biphenyls; methylene chloride; perchloroethylene; trichlorofluoroethane; trichloroethylene; chlorobenzene  

DOE Patents [OSTI]

A process for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contracting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible polyhydroxy compound, such as, water, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds in the low polar or nonpolar solvent by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered for recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 2 tables.

Googin, J.M.; Napier, J.M.; Travaglini, M.A.

1982-03-31T23:59:59.000Z

104

MAGNIFICATION BY GALAXY GROUP DARK MATTER HALOS  

SciTech Connect (OSTI)

We report on the detection of gravitational lensing magnification by a population of galaxy groups, at a significance level of 4.9{sigma}. Using X-ray-selected groups in the COSMOS 1.64 deg{sup 2} field, and high-redshift Lyman break galaxies as sources, we measure a lensing-induced angular cross-correlation between the samples. After satisfying consistency checks that demonstrate we have indeed detected a magnification signal, and are not suffering from contamination by physical overlap of samples, we proceed to implement an optimally weighted cross-correlation function to further boost the signal to noise of the measurement. Interpreting this optimally weighted measurement allows us to study properties of the lensing groups. We model the full distribution of group masses using a composite-halo approach, considering both the singular isothermal sphere and Navarro-Frenk-White profiles, and find our best-fit values to be consistent with those recovered using the weak-lensing shear technique. We argue that future weak-lensing studies will need to incorporate magnification along with shear, both to reduce residual systematics and to make full use of all available source information, in an effort to maximize scientific yield of the observations.

Ford, Jes; Hildebrandt, Hendrik; Van Waerbeke, Ludovic [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Leauthaud, Alexie; Tanaka, Masayuki [Institute for the Physics and Mathematics of the Universe, University of Tokyo, Chiba 277-8582 (Japan); Capak, Peter [NASA Spitzer Science Center, California Institute of Technology, 220-6 Caltech, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Finoguenov, Alexis [Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); George, Matthew R. [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Rhodes, Jason [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

2012-08-01T23:59:59.000Z

105

Sensitivity of Tropospheric Chemical Composition to Halogen-Radical Chemistry Using a Fully Coupled Size-Resolved Multiphase Chemistry-Global Climate System: Halogen Distributions, Aerosol Composition, and Sensitivity of Climate-Relevant Gases  

SciTech Connect (OSTI)

Observations and model studies suggest a significant but highly non-linear role for halogens, primarily Cl and Br, in multiphase atmospheric processes relevant to tropospheric chemistry and composition, aerosol evolution, radiative transfer, weather, and climate. The sensitivity of global atmospheric chemistry to the production of marine aerosol and the associated activation and cycling of inorganic Cl and Br was tested using a size-resolved multiphase coupled chemistry/global climate model (National Center for Atmospheric Researchs Community Atmosphere Model (CAM); v3.6.33). Simulation results showed strong meridional and vertical gradients in Cl and Br species. The simulation reproduced most available observations with reasonable confidence permitting the formulation of potential mechanisms for several previously unexplained halogen phenomena including the enrichment of Br- in submicron aerosol, and the presence of a BrO maximum in the polar free troposphere. However, simulated total volatile Br mixing ratios were generally high in the troposphere. Br in the stratosphere was lower than observed due to the lack of long-lived organobromine species in the simulation. Comparing simulations using chemical mechanisms with and without reactive Cl and Br species demonstrated a significant temporal and spatial sensitivity of primary atmospheric oxidants (O3, HOx, NOx), CH4, and non-methane hydrocarbons (NMHCs) to halogen cycling. Simulated O3 and NOx were globally lower (65% and 35%, respectively, less in the planetary boundary layer based on median values) in simulations that included halogens. Globally, little impact was seen in SO2 and non-sea-salt SO42- processing due to halogens. Significant regional differences were evident: The lifetime of nss-SO42- was extended downwind of large sources of SO2. The burden and lifetime of DMS (and its oxidation products) were lower by a factor of 5 in simulations that included halogens, versus those without, leading to a 20% reduction in nss-SO42- in the southern hemisphere planetary boundary layer based on median values.

Long, M.; Keene, W. C.; Easter, Richard C.; Sander, Rolf; Liu, Xiaohong; Kerkweg, A.; Erickson, D.

2014-04-07T23:59:59.000Z

106

Solid-State Halogen Atom Source for Chemical Dynamics and Etching. | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administrationcontroller systemsBiSite CulturalDepartment2) 1/8Advanced MaterialsHalogen Atom Source

107

Deoxybenzoin-Based Polyarylates as Halogen-Free Fire-Resistant Kenneth A. Ellzey, T. Ranganathan, Joseph Zilberman, E. Bryan Coughlin,*  

E-Print Network [OSTI]

, processing, and engineering of halogen-free, low heat release, fire-resistant materials present important with high carbon monoxide emis- sion.7,8 Ideal flame-retardant polymers would possess high thermal stabilityDeoxybenzoin-Based Polyarylates as Halogen-Free Fire-Resistant Polymers Kenneth A. Ellzey, T

108

Process for the solvent extraction for the radiolysis and dehalogenation of halogenated organic compounds in soils, sludges, sediments and slurries  

DOE Patents [OSTI]

A process of extracting halogenated organic compounds, and particularly PCBs, from soil, sediment, slurry, sludge and dehalogenating the compounds contacts a contaminated soil sample with an extraction medium of a mixture of an alkane and a water miscible alcohol. The organic compounds dissolve in the extraction medium which is separated from the soil by passing water upwardly through the soil. The extraction medium floats to the surface of the water and is separated. Thereafter, the extraction medium containing the halogenated organic contaminants is subjected to ionizing radiation to radiolytically dehalogenate the compounds.

Mincher, Bruce J.; Curry, Randy Dale; Clevenger, Thomas E.; Golden, Jeffry

2003-05-27T23:59:59.000Z

109

Process for the solvent extraction for the radiolysis and dehalogenation of halogenated organic compounds in soils, sludges, sediments and slurries  

DOE Patents [OSTI]

A process of extracting halogenated organic compounds, and particularly PCBs, from soil, sediment, slurry, sludge and dehalogenating the compounds contacts a contaminated soil sample with an extraction medium of a mixture of an alkane and a water miscible alcohol. The organic compounds dissolve in the extraction medium which is separated from the soil by passing water upwardly through the soil. The extraction medium floats to the surface of the water and is separated. Thereafter, the extraction medium containing the halogenated organic contaminants is subjected to ionizing radiation to radiolytically dehalogenate the compounds.

Golden, Jeffry

2007-02-13T23:59:59.000Z

110

Process for the solvent extraction for the radiolysis and dehalogenation of halogenated organic compounds in soils, sludges, sediments and slurries  

DOE Patents [OSTI]

A process of extracting halogenated organic compounds, and particularly PCBs, from soil, sediment, slurry, sludge and dehalogenating the compounds contacting a contaminated soil sample with an extraction medium of a mixture of an alkane and a water miscible alcohol. The organic compounds dissolve in the extraction medium which is separated from the soil by passing water upwardly through the soil. The extraction medium floats to the surface of the water and is separated. Thereafter, the extraction medium containing the halogenated organic contaminants is subjected to ionizing radiation to radiolytically dehalogenate the compounds.

Mincher, Bruce J. (3705 Creekside Dr., Idaho Falls, ID 83404); Curry, Randy Dale (1104 Merrill Ct., Columbia, MO 65203); Clevenger, Thomas E. (2512 Bluff Blvd., Columbia, MO 65201); Golden, Jeffry (12612 Cedarbrook La., Laurel, MD 20708)

2000-01-01T23:59:59.000Z

111

Bar-Halo Friction in Galaxies II: Metastability  

E-Print Network [OSTI]

It is well-established that strong bars rotating in dense halos generally slow down as they lose angular momentum to the halo through dynamical friction. Angular momentum exchanges between the bar and halo particles take place at resonances. While some particles gain and others lose, friction arises when there is an excess of gainers over losers. This imbalance results from the generally decreasing numbers of particles with increasing angular momentum, and friction can therefore be avoided if there is no gradient in the density of particles across the major resonances. Here we show that anomalously weak friction can occur for this reason if the pattern speed of the bar fluctuates upwards. After such an event, the density of resonant halo particles has a local inflexion created by the earlier exchanges, and bar slowdown can be delayed for a long period; we describe this as a metastable state. We show that this behavior in purely collisionless N-body simulations is far more likely to occur in methods with adaptive resolution. We also show that the phenomenon could arise in nature, since bar-driven gas inflow could easily raise the bar pattern speed enough to reach the metastable state. Finally, we demonstrate that mild external, or internal, perturbations quickly restore the usual frictional drag, and it is unlikely therefore that a strong bar in a galaxy having a dense halo could rotate for a long period without friction.

J. A. Sellwood; Victor P. Debattista

2005-11-05T23:59:59.000Z

112

Environment Dependence of Dark Matter Halos in Symmetron Modified Gravity  

E-Print Network [OSTI]

We investigate the environment dependence of dark matter halos in the symmetron modified gravity scenario. The symmetron is one of three known mechanisms for screening a fifth-force and thereby recovering General Relativity in dense environments. The effectiveness of the screening depends on both the mass of the object and the environment it lies in. Using high-resolution N-body simulations we find a significant difference, which depends on the halos mass and environment, between the lensing and dynamical masses of dark matter halos similar to the f(R) modified gravity. The symmetron can however yield stronger signatures due to a freedom in the strength of the coupling to matter.

Hans A. Winther; David F. Mota; Baojiu Li

2011-10-28T23:59:59.000Z

113

E-Print Network 3.0 - alpha emission halo Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

emission halo Search Powered by Explorit Topic List Advanced Search Sample search results for: alpha emission halo Page: << < 1 2 3 4 5 > >> 1 arXiv:1009.6108v1astro-ph.CO30Sep20...

114

Introduction The Fiber-Lite MI-150 is a 150 Watt quartz halogen fiber optic illuminator designed for general microscopy  

E-Print Network [OSTI]

Introduction ® The Fiber-Lite MI-150 is a 150 Watt quartz halogen fiber optic illuminator designed for general microscopy use. When used with specialty fiber optic cables the MI-150 illuminator can also Illuminator from the carton and retain the manual and any additional documents. ! Remove the fiber optic cable

Kleinfeld, David

115

Suppressed fusion cross section for neutron halo nuclei  

E-Print Network [OSTI]

Fusion reactions of neutron-halo nuclei are investigated theoretically with a three-body model. The time-dependent wave-packet method is used to solve the three-body Schrodinger equation. The halo neutron behaves as a spectator during the Coulomb dissociation process of the projectile. The fusion cross sections of 11Be-209Bi and 6He-238U are calculated and are compared with measurements. Our calculation indicates that the fusion cross section is slightly hindered by the presence of weakly bound neutrons.

Makoto Ito; Kazuhiro Yabana; Takashi Nakatsukasa; Manabu Ueda

2006-01-20T23:59:59.000Z

116

A Model for the Density Distribution of Virialized CDM Halos  

E-Print Network [OSTI]

An analytic collapse model for the formation and density distribution of virialized cold dark matter halos is proposed. Hierarchical structure formation is taken into account explicitly. Monte Carlo methods are used to generate samples of mass histories of virialized halos. The mean density distribution found from the collapse model is in good agreement with numerical results in the mass range from $10^{11}M_\\odot$ to $10^{15}M_\\odot$ and in the radial range form $0.05 r_{200}$ to $r_{200}$.

A. Kull

1999-02-20T23:59:59.000Z

117

The density profiles of hot galactic halo gas  

E-Print Network [OSTI]

Extended gas haloes around galaxies are a ubiquitous prediction of galaxy formation scenarios. However, the density profiles of this hot halo gas is virtually unknown, although various profiles have been suggested on theoretical grounds. In order to quantitatively address the gas profile, we compare galaxies from direct cosmological simulations with analytical solutions of the underlying gas equations. We find remarkable agreement between simulations and theoretical predictions. We present an expression for this gas profile with a non-trivial dependence on the total mass profile. This expression is useful when setting up equilibrium galaxy models for numerical experiments.

Steen H. Hansen; Jesper Sommer-Larsen

2006-06-13T23:59:59.000Z

118

Dark Matter Halos as Bose-Einstein Condensates  

E-Print Network [OSTI]

Galactic dark matter is modelled by a scalar field in order to effectively modify Kepler's law without changing standard Newtonian gravity. In particular, a solvable toy model with a self-interaction U(Phi) borrowed from non-topological solitons produces already qualitatively correct rotation curves and scaling relations. Although relativistic effects in the halo are very small, we indicate corrections arising from the general relativistic formulation. Thereby, we can also probe the weak gravitational lensing of our soliton type halo. For cold scalar fields, it corresponds to a gravitationally confined Boson-Einstein condensate, but of galactic dimensions.

Eckehard W. Mielke; Burkhard Fuchs; Franz E. Schunck

2006-08-24T23:59:59.000Z

119

Are the red halos of galaxies made of low-mass stars? Constraints from subdwarf star counts in the Milky Way halo  

E-Print Network [OSTI]

Surface photometry detections of red and exceedingly faint halos around galaxies have resurrected the old question of whether some non-negligible fraction of the missing baryons of the Universe could be hiding in the form of faint, hydrogen-burning stars. The optical/near-infrared colours of these red halos have proved very difficult to reconcile with any normal type of stellar population, but can in principle be explained by advocating a bottom-heavy stellar initial mass function. This implies a high stellar mass-to-light ratio and hence a substantial baryonic mass locked up in such halos. Here, we explore the constraints imposed by current observations of ordinary stellar halo subdwarfs on a putative red halo of low-mass stars around the Milky Way. Assuming structural parameters similar to those of the red halo recently detected in stacked images of external disk galaxies, we find that a smooth halo component with a bottom-heavy initial mass function is completely ruled out by current star count data for the Milky Way. All viable smooth red halo models with a density slope even remotely similar to that of the stacked halo moreover contain far too little mass to have any bearing on the missing-baryon problem. However, we note that these constraints can be sidestepped if the red halo stars are locked up in star clusters, and discuss potential observations of other nearby galaxies that may be able to put such scenarios to the test.

E. Zackrisson; C. Flynn

2008-09-17T23:59:59.000Z

120

In situ thermally enhanced biodegradation of petroleum fuel hydrocarbons and halogenated organic solvents  

DOE Patents [OSTI]

An in situ thermally enhanced microbial remediation strategy and a method for the biodegradation of toxic petroleum fuel hydrocarbon and halogenated organic solvent contaminants are described. The method utilizes nonpathogenic, thermophilic bacteria for the thermal biodegradation of toxic and carcinogenic contaminants, such as benzene, toluene, ethylbenzene and xylenes, from fuel leaks and the chlorinated ethenes, such as trichloroethylene, chlorinated ethanes, such as 1,1,1-trichloroethane, and chlorinated methanes, such as chloroform, from past solvent cleaning practices. The method relies on and takes advantage of the pre-existing heated conditions and the array of delivery/recovery wells that are created and in place following primary subsurface contaminant volatilization efforts via thermal approaches, such as dynamic underground steam-electrical heating. 21 figs.

Taylor, R.T.; Jackson, K.J.; Duba, A.G.; Chen, C.I.

1998-05-19T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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

In situ thermally enhanced biodegradation of petroleum fuel hydrocarbons and halogenated organic solvents  

DOE Patents [OSTI]

An in situ thermally enhanced microbial remediation strategy and a method for the biodegradation of toxic petroleum fuel hydrocarbon and halogenated organic solvent contaminants. The method utilizes nonpathogenic, thermophilic bacteria for the thermal biodegradation of toxic and carcinogenic contaminants, such as benzene, toluene, ethylbenzene and xylenes, from fuel leaks and the chlorinated ethenes, such as trichloroethylene, chlorinated ethanes, such as 1,1,1-trichloroethane, and chlorinated methanes, such as chloroform, from past solvent cleaning practices. The method relies on and takes advantage of the pre-existing heated conditions and the array of delivery/recovery wells that are created and in place following primary subsurface contaminant volatilization efforts via thermal approaches, such as dynamic underground steam-electrical heating.

Taylor, Robert T. (Livermore, CA); Jackson, Kenneth J. (San Leandro, CA); Duba, Alfred G. (Livermore, CA); Chen, Ching-I (Danville, CA)

1998-01-01T23:59:59.000Z

122

FIELD SCREENING FOR HALOGENATED VOLATILE ORGANIC COMPOUNDS: THE NEW X-WAND HVOC SCREENING DEVICE  

SciTech Connect (OSTI)

Western Research Institute (WRI) has developed new methodology and a test kit to screen soil or water samples for halogenated volatile organic compounds (HVOCs) in the field. The technology has been designated the X-Wand{trademark} screening tool. The new device uses a heated diode sensor that is commonly used to detect leaks of refrigerants from air conditioners, freezers, and refrigerators. This sensor is selective to halogens. It does not respond to volatile aromatic hydrocarbons, such as those in gasoline, and it is not affected by high humidity. In the current work, the heated diode leak detectors were modified further to provide units with rapid response and enhanced sensitivity. The limit of detection for trichloroethylene TCE in air is 0.1 mg/m{sup 3} (S/N = 2). The response to other HVOCS relative to TCE is similar. Variability between sensors and changes in a particular sensor over time can be compensated for by normalizing sensor readings to a maximum sensor reading at 1,000 mg/m{sup 3} TCE. The soil TCE screening method was expanded to include application to water samples. Assuming complete vaporization, the detection limit for TCE in soil is about 1 ug/kg (ppb) for a 25-g sample in an 8-oz jar. The detection limit for TCE in water is about 1 ug/L (ppb) for a 25-mL sample in an 8-oz jar. This is comparable to quantitation limits of EPA GC/MS laboratory methods. A draft ASTM method for screening TCE contaminated soils using a heated diode sensor was successfully submitted for concurrent main committee and subcommittee balloting in ASTM Committee D 34 on Waste Management. The method was approved as ASTM D 7203-05, Standard Test Method for Screening Trichloroethylene (TCE)-Contaminated Soil Using a Heated Diode Sensor.

John F. Schabron; Susan S. Sorini; Joseph F. Rovani Jr

2006-03-01T23:59:59.000Z

123

Red Halos of Galaxies - Reservoirs of Baryonic Dark Matter?  

E-Print Network [OSTI]

Deep optical/near-IR surface photometry of galaxies outside the Local Group have revealed faint and very red halos around objects as diverse as disk galaxies and starbursting dwarf galaxies. The colours of these structures are too extreme to be reconciled with stellar populations similar to those seen in the stellar halos of the Milky Way or M31, and alternative explanations like dust reddening, high metallicities or nebular emission are also disfavoured. A stellar population obeying an extremely bottom-heavy initial mass function (IMF), is on the other hand consistent with all available data. Because of its high mass-to-light ratio, such a population would effectively behave as baryonic dark matter and could account for some of the baryons still missing in the low-redshift Universe. Here, we give an overview of current red halo detections, alternative explanations for the origin of the red colours and ongoing searches for red halos around types of galaxies for which this phenomenon has not yet been reported. A number of potential tests of the bottom-heavy IMF hypothesis are also discussed.

E. Zackrisson; N. Bergvall; C. Flynn; G. Ostlin; G. Micheva; B. Caldwell

2007-08-06T23:59:59.000Z

124

MODELLING OF THE TOROIDAL ASYMMETRY OF POLOIDAL HALO CURRENTS  

E-Print Network [OSTI]

currents, and these can be of substantial magnitude. Of particular concern for tokamak design and operation is the observed toroidal asymmetry of the halo current distribution: such an asymmetric distribution leads to prob, since the force distribution on the conducting structures depends mainly on the `resistive distribution

125

The Star Formation History in the Andromeda Halo  

E-Print Network [OSTI]

I present the preliminary results of a program to measure the star formation history in the halo of the Andromeda galaxy. Using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope, we obtained the deepest optical images of the sky to date, in a field on the southeast minor axis of Andromeda, 51 arcmin (11 kpc) from the nucleus. The resulting color-magnitude diagram (CMD) contains approximately 300,000 stars and extends more than 1.5 mag below the main sequence turnoff, with 50% completeness at V=30.7 mag. We interpret this CMD using comparisons to ACS observations of five Galactic globular clusters through the same filters, and through chi-squared fitting to a finely-spaced grid of calibrated stellar population models. We find evidence for a major (approximately 30%) intermediate-age (6-8 Gyr) metal-rich ([Fe/H] > -0.5) population in the Andromeda halo, along with a significant old metal-poor population akin to that in the Milky Way halo. The large spread in ages suggests that the Andromeda halo formed as a result of a more violent merging history than that in our own Milky Way.

Thomas M. Brown

2003-08-18T23:59:59.000Z

126

Formation and evolution of CDM halos and their substructure  

E-Print Network [OSTI]

solution of the idealized problem complementary approach: hydro-dynamical simulations - computationally expensive, resolution relatively low - hydro is not trivial (SPH and grid codes often disagree, e.g. Agertz there is a cutoff at about 10-6 Msun due to free streaming small, "micro"-halos should forming around z=40

California at Santa Cruz, University of

127

HALO ORBITS IN COSMOLOGICAL DISK GALAXIES: TRACERS OF FORMATION HISTORY  

SciTech Connect (OSTI)

We analyze the orbits of stars and dark matter particles in the halo of a disk galaxy formed in a cosmological hydrodynamical simulation. The halo is oblate within the inner {approx}20 kpc and triaxial beyond this radius. About 43% of orbits are short axis tubes-the rest belong to orbit families that characterize triaxial potentials (boxes, long-axis tubes and chaotic orbits), but their shapes are close to axisymmetric. We find no evidence that the self-consistent distribution function of the nearly oblate inner halo is comprised primarily of axisymmetric short-axis tube orbits. Orbits of all families and both types of particles are highly eccentric, with mean eccentricity {approx}> 0.6. We find that randomly selected samples of halo stars show no substructure in 'integrals of motion' space. However, individual accretion events can clearly be identified in plots of metallicity versus formation time. Dynamically young tidal debris is found primarily on a single type of orbit. However, stars associated with older satellites become chaotically mixed during the formation process (possibly due to scattering by the central bulge and disk, and baryonic processes), and appear on all four types of orbits. We find that the tidal debris in cosmological hydrodynamical simulations experiences significantly more chaotic evolution than in collisionless simulations, making it much harder to identify individual progenitors using phase space coordinates alone. However, by combining information on stellar ages and chemical abundances with the orbital properties of halo stars in the underlying self-consistent potential, the identification of progenitors is likely to be possible.

Valluri, Monica [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States)] [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Debattista, Victor P. [Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE (United Kingdom)] [Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Stinson, Gregory S. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany)] [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Bailin, Jeremy [Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487-0324 (United States)] [Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487-0324 (United States); Quinn, Thomas R. [Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States)] [Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States); Couchman, H. M. P.; Wadsley, James, E-mail: mvalluri@umich.edu [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada)] [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada)

2013-04-10T23:59:59.000Z

128

HOT GAS HALOS IN EARLY-TYPE FIELD GALAXIES  

SciTech Connect (OSTI)

We use Chandra and XMM-Newton to study the hot gas content in a sample of field early-type galaxies. We find that the L {sub X}-L {sub K} relationship is steeper for field galaxies than for comparable galaxies in groups and clusters. The low hot gas content of field galaxies with L {sub K} {approx_lt} L {sub *} suggests that internal processes such as supernovae-driven winds or active galactic nucleus feedback expel hot gas from low-mass galaxies. Such mechanisms may be less effective in groups and clusters where the presence of an intragroup or intracluster medium can confine outflowing material. In addition, galaxies in groups and clusters may be able to accrete gas from the ambient medium. While there is a population of L {sub K} {approx_lt} L {sub *} galaxies in groups and clusters that retain hot gas halos, some galaxies in these rich environments, including brighter galaxies, are largely devoid of hot gas. In these cases, the hot gas halos have likely been removed via ram pressure stripping. This suggests a very complex interplay between the intragroup/intracluster medium and hot gas halos of galaxies in rich environments, with the ambient medium helping to confine or even enhance the halos in some cases and acting to remove gas in others. In contrast, the hot gas content of more isolated galaxies is largely a function of the mass of the galaxy, with more massive galaxies able to maintain their halos, while in lower mass systems the hot gas escapes in outflowing winds.

Mulchaey, John S. [Observatories of the Carnegie Institution of Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Jeltema, Tesla E., E-mail: mulchaey@obs.carnegiescience.ed, E-mail: tesla@ucolick.or [UCO/Lick Observatories, 1156 High Street, Santa Cruz, CA 95064 (United States)

2010-05-20T23:59:59.000Z

129

Microscopic and self-consistent description for neutron halo in deformed nuclei  

SciTech Connect (OSTI)

A deformed relativistic Hartree-Bogoliubov theory in continuum has been developed for the study of neutron halos in deformed nuclei and the halo phenomenon in deformed weakly bound nuclei is investigated. Magnesium and neon isotopes are studied and some results are presented for the deformed neutron-rich and weakly bound nuclei {sup 44}Mg and {sup 36}Ne. The core of the former nucleus is prolate, but the halo has a slightly oblate shape. This indicates a decoupling of the halo orbitals from the deformation of the core. The generic conditions for the existence of halos in deformed nuclei and for the occurrence of this decoupling effect are discussed.

Li Lulu [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Meng Jie [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China) and Department of Physics, University of Stellenbosch, Stellenbosch (South Africa); Zhao Enguang; Zhou Shangui [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China) and Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 (China)

2013-05-06T23:59:59.000Z

130

Instructions for Corning Model 220 pH Meter The electrode tip is a fragile glass bulb. Be careful or you will break it with a  

E-Print Network [OSTI]

Instructions for Corning Model 220 pH Meter The electrode tip is a fragile glass bulb. Be careful. Two Point Calibration Routine · The pH meter should be turned "ON". · Your buffers should from your sample, rinse with distilled water, and BLOT with a kimwipe. 4. Turn pH meter OFF and store

Cross, George

131

HaloTag protein-mediated specific labeling of living cells with quantum dots Min-kyung So, Hequan Yao 1  

E-Print Network [OSTI]

Tag protein (HTP) [25]. The na- tive HTP is a monomeric protein (MW $ 33 KDa) that cleaves car- bon halogen

Rao, Jianghong

132

Density waves in the shearing sheet IV. Interaction with a live dark halo  

E-Print Network [OSTI]

It is shown that if the self-gravitating shearing sheet, a model of a patch of a galactic disk, is embedded in a live dark halo, this has a strong effect on the dynamics of density waves in the sheet. I describe how the density waves and the halo interact via halo particles either on orbits in resonance with the wave or on non-resonant orbits. Contrary to expectation the presence of the halo leads to a very considerable enhancement of the amplitudes of the density waves in the shearing sheet. This effect appears to be the equivalent of the recently reported enhanced growth of bars in numerically simulated stellar disks embedded in live dark halos. Finally I discuss the transfer of linear momentum from a density wave in the sheet to the halo and show that it is mediated only by halo particles on resonant orbits.

B. Fuchs

2004-03-01T23:59:59.000Z

133

Evidence in Virgo for the Universal Dark Matter Halo  

E-Print Network [OSTI]

A model is constructed for the mass and dynamics of M87 and the Virgo Cluster. Existing surface photometry of the galaxy, mass estimates from X-ray observations of the hot intracluster gas, and the velocity dispersions of early-type Virgo galaxies, all are used to constrain the run of dark matter density over radii to 2 Mpc in the cluster. The ``universal'' halo advocated by Navarro, Frenk, & White provides an excellent description of the combined data, as does a Hernquist profile. These models are favored over isothermal spheres, and their central structure is preferred to density cusps either much stronger or much weaker than r^{-1}. The galaxies and gas in the cluster trace its total mass distribution, the galaxies' velocity ellipsoid is close to isotropic, and the gas temperature follows the virial temperature profile of the dark halo. The virial radius and mass and the intracluster gas fraction of Virgo are evaluated.

Dean E. McLaughlin

1998-12-12T23:59:59.000Z

134

Dark energy parameterizations and their effect on dark halos  

E-Print Network [OSTI]

There is a plethora of dark energy parameterizations that can fit current supernovae Ia data. However, this data is only sensitive to redshifts up to order one. In fact, many of these parameterizations break down at higher redshifts. In this paper we study the effect of dark energy models on the formation of dark halos. We select a couple of dark energy parameterizations which are sensible at high redshifts and compute their effect on the evolution of density perturbations in the linear and non-linear regimes. Using the Press-Schechter formalism we show that they produce distinguishable signatures in the number counts of dark halos. Therefore, future observations of galaxy clusters can provide complementary constraints on the behavior of dark energy.

Lamartine Liberato; Rogerio Rosenfeld

2006-04-19T23:59:59.000Z

135

Neutron structure effects in the deuteron and one neutron halos  

E-Print Network [OSTI]

Although the neutron (n) does not carry a total electric charge, its charge and magnetization distributions represented in momentum space by the electromagnetic form factors, $F_1^{(n)} (q^2)$ and $F_2^{(n)} (q^2)$, lead to an electromagnetic potential of the neutron. Using this fact, we calculate the electromagnetic corrections to the binding energy, $B_d$, of the deuteron and a one neutron halo nucleus (11Be), by evaluating the neutron-proton and the neutron-charged core (10Be) potential, respectively. The correction to $B_d$ (~9 keV) is comparable to that arising due to the inclusion of the $\\Delta$-isobar component in the deuteron wave function. In the case of the more loosely bound halo nucleus, 11Be, the correction is close to about 2 keV.

M. Nowakowski; N. G. Kelkar; T. Mart

2005-11-28T23:59:59.000Z

136

ON THE HOT GAS CONTENT OF THE MILKY WAY HALO  

SciTech Connect (OSTI)

The Milky Way appears to be missing baryons, as the observed mass in stars and gas is well below the cosmic mean. One possibility is that a substantial fraction of the Galaxy's baryons are embedded within an extended, million-degree hot halo, an idea supported indirectly by observations of warm gas clouds in the halo and gas-free dwarf spheroidal satellites. X-ray observations have established that hot gas does exist in our Galaxy beyond the local hot bubble; however, it may be distributed in a hot disk configuration. Moreover, recent investigations into the X-ray constraints have suggested that any Galactic corona must be insignificant. Here we re-examine the observational data, particularly in the X-ray and radio bands, in order to determine whether it is possible for a substantial fraction of the Galaxy's baryons to exist in {approx}10{sup 6} K gas. In agreement with past studies, we find that a baryonically closed halo is clearly ruled out if one assumes that the hot corona is distributed with a cuspy Navarro-Frenk-White profile. However, if the hot corona of the galaxy is in an extended, low-density distribution with a large central core, as expected for an adiabatic gas in hydrostatic equilibrium, then it may contain up to 10{sup 11} M {sub Sun} of material, possibly accounting for all of the missing Galactic baryons. We briefly discuss some potential avenues for discriminating between a massive, extended hot halo and a local hot disk.

Fang, Taotao [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, Fujian 361005 (China)] [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, Fujian 361005 (China); Bullock, James; Boylan-Kolchin, Michael [Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697 (United States)] [Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697 (United States)

2013-01-01T23:59:59.000Z

137

The Dark Matter halo of the Milky Way, AD 2013  

SciTech Connect (OSTI)

We derive the mass model of the Milky Way (MW), crucial for Dark Matter (DM) direct and indirect detection, using recent data and a cored dark matter (DM) halo profile, which is favoured by studies of external galaxies. The method used consists in fitting a spherically symmetric model of the Galaxy with a Burkert DM halo profile to available data: MW terminal velocities in the region inside the solar circle, circular velocity as recently estimated from maser star forming regions at intermediate radii, and velocity dispersions of stellar halo tracers for the outermost Galactic region. The latter are reproduced by integrating the Jeans equation for every modeled mass distribution, and by allowing for different velocity anisotropies for different tracer populations. For comparison we also consider a Navarro-Frenk-White profile. We find that the cored profile is the preferred one, with a shallow central density of ?{sub H} ? 4 10{sup 7}M{sub ?}/kpc{sup 3} and a large core radius R{sub H} ? 10 kpc, as observed in external spirals and in agreement with the mass model underlying the Universal Rotation Curve of spirals. We describe also the derived model uncertainties, which are crucially driven by the poorly constrained velocity dispersion anisotropies of halo tracers. The emerging cored DM distribution has implications for the DM annihilation angular profile, which is much less boosted in the Galactic center direction with respect to the case of the standard ?CDM, NFW profile. Using the derived uncertainties we discuss finally the limitations and prospects to discriminate between cored and cusped DM profile with a possible observed diffuse DM annihilation signal. The present mass model aims to characterize the present-day description of the distribution of matter in our Galaxy, which is needed to frame current crucial issues of Cosmology, Astrophysics and Elementary Particles.

Nesti, Fabrizio [Gran Sasso Science Institute, viale Crispi 7, I-67100 L'Aquila (Italy); Salucci, Paolo, E-mail: nesti@aquila.infn.it, E-mail: salucci@sissa.it [Scuola Internazionale Superiore di Studi Avanzati (SISSA/ISAS), Via Bonomea 265, I-34136 Trieste (Italy)

2013-07-01T23:59:59.000Z

138

A Critical Examination of Halo White Dwarf Candidates  

E-Print Network [OSTI]

A detailed analysis of halo white dwarf candidates is presented, which is based on model atmosphere fits to observed energy distributions built from photoelectric or photographic magnitudes. Most of the candidates identified in reduced proper motion diagrams are shown to be too warm (Teff > 5000 K) and most likely too young to be members of the galactic halo, while the tangential velocities of the cooler and thus older white dwarfs are shown to be entirely consistent with the disk population. The results suggest that some white dwarf stars born in the young disk may have high velocities with respect to the local standard of rest. Such objects could represent the remnants of donor stars from close mass-transfer binaries that produced type Ia supernovae via the single degenerate channel, or other scenarios suggested in the literature. Ongoing surveys that rely solely on reduced proper motion diagrams are likely to identify more of these high velocity young degenerates, rather than to unveil the old white dwarf population of the galactic halo. The importance of infrared photometry for studying extremely cool white dwarfs is also emphasized.

P. Bergeron

2002-11-26T23:59:59.000Z

139

Merger Histories of Galaxy Halos and Implications for Disk Survival  

SciTech Connect (OSTI)

The authors study the merger histories of galaxy dark matter halos using a high resolution {Lambda}CDM N-body simulation. The merger trees follow {approx} 17,000 halos with masses M{sub 0} = (10{sup 11} - 10{sup 13})h{sup -1}M{sub {circle_dot}} at z = 0 and track accretion events involving objects as small as m {approx_equal} 10{sup 10} h{sup -1}M{sub {circle_dot}}. They find that mass assembly is remarkably self-similar in m/M{sub 0}, and dominated by mergers that are {approx}10% of the final halo mass. While very large mergers, m {approx}> 0.4 M{sub 0}, are quite rare, sizeable accretion events, m {approx} 0.1 M{sub 0}, are common. Over the last {approx} 10 Gyr, an overwhelming majority ({approx} 95%) of Milky Way-sized halos with M{sub 0} = 10{sup 12} h{sup -1}M{sub {circle_dot}} have accreted at least one object with greater total mass than the Milky Way disk (m > 5 x 10{sup 10} h{sup -1}M{sub {circle_dot}}), and approximately 70% have accreted an object with more than twice that mass (m > 10{sup 11} h{sup -1}M{sub {circle_dot}}). The results raise serious concerns about the survival of thin-disk dominated galaxies within the current paradigm for galaxy formation in a {Lambda}CDM universe. in order to achieve a {approx} 70% disk-dominated fraction in Milky Way-sized {Lambda}CDM halos, mergers involving m {approx_equal} 2 x 10{sup 11} h{sup -1}M{sub {circle_dot}} objects must not destroy disks. Considering that most thick disks and bulges contain old stellar populations, the situation is even more restrictive: these mergers must not heat disks or drive gas into their centers to create young bulges.

Stewart, Kyle R.; Bullock, James S.; Wechsler, Risa H.; Maller, Ariyeh H.; Zentner, Andrew R.

2008-05-16T23:59:59.000Z

140

Electrical Appliances Students may use clocks, sound equipment, computers, electric razors, hair dryers,  

E-Print Network [OSTI]

with a heating coil *Torchiere type lamps with a halogen bulb, and other lamps with a halogen bulb greater than there is specific UL approval for a higher wattage. Violators of any of the above policies will be charged $50, Prohibited Appliances, and Halogen Torchiere Lamps 1st offense: $50.00 fine and the student will be called

Aalberts, Daniel P.

Note: This page contains sample records for the topic "halogen bulbs halo" 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

Halos in a deformed relativistic Hartree-Bogoliubov theory in continuum  

SciTech Connect (OSTI)

In this contribution we present some recent results about neutron halos in deformed nuclei. A deformed relativistic Hartree-Bogoliubov theory in continuumhas been developed and the halo phenomenon in deformed weakly bound nuclei is investigated. These weakly bound quantum systems present interesting examples for the study of the interdependence between the deformation of the core and the particles in the halo. Magnesium and neon isotopes are studied and detailed results are presented for the deformed neutron-rich and weakly bound nuclei {sup 42}Mg. The core of this nucleus is prolate, but the halo has a slightly oblate shape. This indicates a decoupling of the halo orbitals from the deformation of the core. The generic conditions for the existence of halos in deformed nuclei and for the occurrence of this decoupling effect are discussed.

Li Lulu; Meng Jie; Ring, P.; Zhao Enguang; Zhou Shangui [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China) and Department of Physics, University of Stellenbosch, Stellenbosch (South Africa); Physikdepartment, Technische Universitaet Muenchen, 85748 Garching (Germany) and State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China) and Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 (China)

2012-10-20T23:59:59.000Z

142

Beta delayed emission of a proton by a one-neutron halo nucleus  

E-Print Network [OSTI]

Some one-neutron halo nuclei can emit a proton in a beta decay of the halo neutron. The branching ratio towards this rare decay mode is calculated within a two-body potential model of the initial core+neutron bound state and final core+proton scattering states. The decay probability per second is evaluated for the $^{11}$Be, $^{19}$C and $^{31}$Ne one-neutron halo nuclei. It is very sensitive to the neutron separation energy.

D. Baye; E. M. Tursunov

2010-12-28T23:59:59.000Z

143

Beta delayed emission of a proton by a one-neutron halo nucleus  

E-Print Network [OSTI]

Some one-neutron halo nuclei can emit a proton in a beta decay of the halo neutron. The branching ratio towards this rare decay mode is calculated within a two-body potential model of the initial core+neutron bound state and final core+proton scattering states. The decay probability per second is evaluated for the $^{11}$Be, $^{19}$C and $^{31}$Ne one-neutron halo nuclei. It is very sensitive to the neutron separation energy.

Baye, D

2010-01-01T23:59:59.000Z

144

Merging Rate of Dark Matter Halos: Evolution and Dependence on Environment  

E-Print Network [OSTI]

We discuss the impact of the cosmological environment on the evolution of dark matter halos using a high-resolution simulation within a spatially flat LCDM cosmology.

Stefan Gottloeber; Anatoly Klypin; Andrey V. Kravtsov

1999-09-01T23:59:59.000Z

145

Neutron-Neutron Correlations in the Dissociation of Halo Nuclei  

E-Print Network [OSTI]

Studies attempting to probe the spatial configuration of the valence neutrons in two-neutron halo nuclei using the technique of intensity interferometry are described. Following a brief review of the method and its application to earlier measurements of the breakup of 6He, 11Li and 14Be, the results of the analysis of a high statistics data set for 6He are presented. The limitations of the technique, including the assumption of incoherent emission in the breakup and the sensitivity to the continuum states populated in the dissociation rather than the ground state, are discussed.

N. A. Orr

2008-03-06T23:59:59.000Z

146

Core excitation effects in the breakup of halo nuclei  

SciTech Connect (OSTI)

The role of core excitation in the structure and dynamics of two-body halo nuclei is investigated. We present calculations for the resonant breakup of {sup 11}Be on protons at an incident energy of 63.7 MeV/nucleon, where core excitation effects were shown to be important. To describe the reaction, we use a recently developed extension of the DWBA formalism which incorporates these core excitation effects within the no-recoil approximation. The validity of the no-recoil approximation is also examined by comparing with DWBA calculations which take into account core recoil. In addition, calculations with two different continuum representations are presented and compared.

Moro, A. M.; Diego, R. de; Lay, J. A.; Crespo, R.; Johnson, R. C.; Arias, J. M.; Gomez-Camacho, J. [Departamento de FAMN, Universidad de Sevilla, Apartado 1065, E-41080 Sevilla (Spain); Centro de Fisica Nuclear, Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal) and Departamento de Fisica, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Prof. Cavaco Silva, Taguspark (Portugal); Physics Department, University of Surrey, Guildford Surrey, GU2 7XH (United Kingdom); Departamento de FAMN, Universidad de Sevilla, Apartado 1065, E-41080 Sevilla (Spain); Departamento de FAMN, Universidad de Sevilla, Apartado 1065, E-41080 Sevilla (Spain) and Centro Nacional de Aceleradores, Universidad de Sevilla/Junta de Andalucia, E-41092 Sevilla (Spain)

2012-10-20T23:59:59.000Z

147

Separation of toxic metal ions, hydrophilic hydrocarbons, hydrophobic fuel and halogenated hydrocarbons and recovery of ethanol from a process stream  

DOE Patents [OSTI]

This invention provides a process to tremendously reduce the bulk volume of contaminants obtained from an effluent stream produced subsurface remediation. The chemicals used for the subsurface remediation are reclaimed for recycling to the remediation process. Additional reductions in contaminant bulk volume are achieved by the ultra-violet light destruction of halogenated hydrocarbons, and the complete oxidation of hydrophobic fuel hydrocarbons and hydrophilic hydrocarbons. The contaminated bulk volume will arise primarily from the disposal of the toxic metal ions. The entire process is modular, so if there are any technological breakthroughs in one or more of the component process modules, such modules can be readily replaced.

Kansa, Edward J. (Livermore, CA); Anderson, Brian L. (Lodi, CA); Wijesinghe, Ananda M. (Tracy, CA); Viani, Brian E. (Oakland, CA)

1999-01-01T23:59:59.000Z

148

Separation of toxic metal ions, hydrophilic hydrocarbons, hydrophobic fuel and halogenated hydrocarbons and recovery of ethanol from a process stream  

DOE Patents [OSTI]

This invention provides a process to tremendously reduce the bulk volume of contaminants obtained from an effluent stream produced subsurface remediation. The chemicals used for the subsurface remediation are reclaimed for recycling to the remediation process. Additional reductions in contaminant bulk volume are achieved by the ultra-violet light destruction of halogenated hydrocarbons, and the complete oxidation of hydrophobic fuel hydrocarbons and hydrophilic hydrocarbons. The contaminated bulk volume will arise primarily from the disposal of the toxic metal ions. The entire process is modular, so if there are any technological breakthroughs in one or more of the component process modules, such modules can be readily replaced. 3 figs.

Kansa, E.J.; Anderson, B.L.; Wijesinghe, A.M.; Viani, B.E.

1999-05-25T23:59:59.000Z

149

Cosmic Ray Acceleration beyond the Knee up to the Ankle in the Galactic Wind Halo  

E-Print Network [OSTI]

Cosmic Ray Acceleration beyond the Knee up to the Ankle in the Galactic Wind Halo Vladimir Acceleration beyond the Knee up to the Ankle in the Galactic Wind Halo2 radius 100 kpc in this model. This size mechanism to produce the observed CRs beyond the so-called knee at several ?1015 eV to the so-called ankle

150

The Ice Cream Cone Model for Inversing Geometrical Properties of Halo Coronal Mass Ejections  

E-Print Network [OSTI]

the front half ellipse produced by the cone part when the angle of the central axis of the ice cream coneThe Ice Cream Cone Model for Inversing Geometrical Properties of Halo Coronal Mass Ejections Xue Pu recently that most of halo coronal mass ejections (CMEs) may be formed by an ice cream cone-like shell

Zhao, Xuepu

151

The Interaction of the Disk with the Halo MordecaiMark Mac Low 1  

E-Print Network [OSTI]

in the halo or even ejection of mass along open field lines in a galactic wind. In these models, the energy and energy to the halo, as well as opening up lines of sight for ionizing radiation to escape from the disk external sources could contribute). The most likely energy source for these processes are massive OB stars

Low, Mordecai-Mark Mac

152

EMPIRICAL MODELS FOR DARK MATTER HALOS. II. INNER PROFILE SLOPES, DYNAMICAL PROFILES, AND /3  

E-Print Network [OSTI]

simulated dark matter halos better than a Navarro- Frenk-WhiteYlike model with an equal number of parameters]) density profiles of simulated dark matter halos (Navarro et al. 2004). Intriguingly, this function was shown to provide a better fit than thethree-parameter Navarro-Frenk-White (NFW)Ylike model

Terzi, Bal?a

153

Decaying Dark Matter and the Deficit of Dwarf Haloes  

E-Print Network [OSTI]

The hierarchical clustering inherent in Lambda-CDM cosmology seems to produce many of the observed characteristics of large-scale structure. But some glaring problems still remain, including the over-prediction (by a factor 10) of the number of dwarf galaxies within the virialized population of the local group. Several secondary effects have already been proposed to resolve this problem. It is still not clear, however, whether the principal solution rests with astrophysical processes, such as early feedback from supernovae, or possibly with as yet undetermined properties of the dark matter itself. In this paper, we carry out a detailed calculation of the dwarf halo evolution incorporating the effects of a hypothesized dark-matter decay, D -> D'+l, where D is the unstable particle, D' is the more massive daughter particle and l is the other, lighter (or possibly massless) daughter particle. This process preferentially heats the smaller haloes, expanding them during their evolution and reducing their present-day circular velocity. We find that this mechanism can account very well for the factor 4 deficit in the observed number of systems with velocity 10--20 km/s compared to those predicted by the numerical simulations, if dm/m_D' ~ 5-7 x 10^{-5}, where dm is the mass difference between the initial and final states. The corresponding lifetime tau cannot be longer than ~30 Gyr, but may be as short as just a few Gyr.

Majd Abdelqader; Fulvio Melia

2008-06-03T23:59:59.000Z

154

The 3D Geometry of Dark Matter Halos  

E-Print Network [OSTI]

The thickness of the neutral hydrogen layer, coupled with the rotation curve, traces the outer dark matter potential. We estimate the amplitude of the flaring in spiral galaxies from a 3D model of the HI gas. Warps in particular are explicitly parametrized in the form of an harmonical density wave. Applying our method to the galaxy NGC 891, the only model that could fit the observations, and in particular the HI at large height above the plane, includes a strong warp with a line of node almost coinciding with the line of sight. This high-Z HI is not observed at the most extreme velocity channels, those corresponding to high rotational velocities. This is accounted for by the model, since orbits in the tilted planes are not circular, but elongated, with their minor axis in the galaxy plane. Their velocity on the major axis (i.e. at their maximal height above the plane) is then 30% less than in the plane. We finally connect the modelled vertical outer gaseous distribution to the dark matter through hydrodynamical and gravitational equations. Under the assumption of isotropy of the gaseous velocity dispersion, we conclude on a very flattened halo geometry for the galaxy NGC 891 ($q \\approx 0.2$), while a vertical velocity dispersion smaller that the radial one would lead to a less flattened Dark Matter Halo ($q \\approx 0.4-0.5$). Both results however suggests that dark matter is dissipative or has been strongly influenced by the gas dynamics.

J. -F. Becquaert; F. Combes

1997-04-10T23:59:59.000Z

155

Modeling Tidal Streams in evolving dark matter halos  

E-Print Network [OSTI]

We explore whether stellar tidal streams can provide information on the secular, cosmological evolution of the Milky Way's gravitational potential and on the presence of subhalos. We carry out long-term (~t_hubble) N-body simulations of disrupting satellite galaxies in a semi-analytic Galaxy potential where the dark matter halo and the subhalos evolve according to a LCDM cosmogony. All simulations are constrained to end up with the same position and velocity at present. Our simulations account for: (i) the secular evolution of the host halo's mass, size and shape, (ii) the presence of subhalos and (iii) dynamical friction. We find that tidal stream particles respond adiabatically to the Galaxy growth so that, at present, the energy and angular momentum distribution is exclusively determined by the present Galaxy potential. In other words, all present-day observables can only constrain the present mass distribution of the Galaxy independent of its past evolution. We also show that, if the full phase-space distribution of a tidal stream is available, we can accurately determine (i) the present Galaxy's shape and (ii) the amount of mass loss from the stream's progenitor, even if this evolution spanned a cosmologically significant epoch.

Jorge Penarrubia; Andrew J. Benson; David Martinez-Delgado; Hans-Walter Rix

2005-12-20T23:59:59.000Z

156

Induced Nested Galactic Bars Inside Assembling Dark Matter Halos  

E-Print Network [OSTI]

We investigate the formation and evolution of nested bar systems in disk galaxies in a cosmological setting by following the development of an isolated dark matter (DM) and baryon density perturbation. The disks form within the assembling triaxial DM halos and the feedback from the stellar evolution is accounted for in terms of supernovae and OB stellar winds. Focusing on a representative model, we show the formation of an oval disk and of a first generation of nested bars with characteristic sub-kpc and a few kpc sizes. The system evolves through successive dynamical couplings and decouplings, forcing the gas inwards and settles in a state of resonant coupling. The inflow rate can support a broad range of activity within the central kpc, from quasar- to Seyfert-types, supplemented by a vigorous star formation as a by-product. The initial bar formation is triggered in response to the tidal torques from the triaxial DM halo, which acts as a finite perturbation. This first generation of bars does not survive for more than 4--5 Gyr: by that time the secondary bar has totally dissolved, while the primary one has very substantially weakened, reduced to a fat oval. This evolution is largely due to chaos introduced by the interaction of the multiple non-axisymmetric components.

Clayton Heller; Isaac Shlosman; Lia Athanassoula

2007-06-26T23:59:59.000Z

157

IMPROVED MODELING OF THE MASS DISTRIBUTION OF DISK GALAXIES BY THE EINASTO HALO MODEL  

SciTech Connect (OSTI)

Analysis of the rotation curves (RCs) of spiral galaxies provides an efficient diagnostic for studying the properties of dark matter halos and their relations with baryonic material. Since the cored pseudo-isothermal (Iso) model usually provides a better description of observed RCs than does the cuspy Navarro-Frenk-White (NFW) model, there have been concerns that the {Lambda}CDM primordial density fluctuation spectrum may not be the correct one. We have modeled the RCs of galaxies from The H I Nearby Galaxy Survey (THINGS) with the Einasto halo model, which has emerged as the best-fitting model of the halos arising in dissipationless cosmological N-body simulations. We find that the RCs are significantly better fit with the Einasto halo than with either Iso or NFW halo models. In our best-fit Einasto models, the radius of density slope -2 and the density at this radius are highly correlated. The Einasto index, which controls the overall shape of the density profile, is near unity on average for intermediate and low mass halos. This is not in agreement with the predictions from {Lambda}CDM simulations. The indices of the most massive halos are in rough agreement with those cosmological simulations and appear correlated with the halo virial mass. We find that a typical Einasto density profile declines more strongly in its outermost parts than any of the Iso or NFW models whereas it is relatively shallow in its innermost regions. The core nature of those regions of halos thus extends the cusp-core controversy found for the NFW model with low surface density galaxies to the Einasto halo with more massive galaxies like those of THINGS. The Einasto concentrations decrease as a function of halo mass, in agreement with trends seen in numerical simulations. However, they are generally smaller than values expected for simulated Einasto halos. We thus find that, so far, the Einasto halo model provides the best match to the observed RCs and can therefore be considered as a new standard model for dark matter halos.

Chemin, Laurent [Universite de Bordeaux, Observatoire Aquitain des Sciences de l'Univers, BP 89, 33271 Floirac Cedex (France); De Blok, W. J. G. [ACGC, Department of Astronomy, University of Cape Town, Rondebosch 7700 (South Africa); Mamon, Gary A., E-mail: chemin@obs.u-bordeaux1.fr, E-mail: edeblok@ast.uct.ac.za, E-mail: gam@iap.fr [Institut d'Astrophysique de Paris (UMR 7095: CNRS and UPMC), 98 bis Bd. Arago, 75014 Paris (France)

2011-10-15T23:59:59.000Z

158

THE SPIN AND ORIENTATION OF DARK MATTER HALOS WITHIN COSMIC FILAMENTS  

SciTech Connect (OSTI)

Clusters, filaments, sheets, and voids are the building blocks of the cosmic web. Forming dark matter halos respond to these different large-scale environments, and this in turn affects the properties of galaxies hosted by the halos. It is therefore important to understand the systematic correlations of halo properties with the morphology of the cosmic web, as this informs both about galaxy formation physics and possible systematics of weak lensing studies. In this study, we present and compare two distinct algorithms for finding cosmic filaments and sheets, a task which is far less well established than the identification of dark matter halos or voids. One method is based on the smoothed dark matter density field and the other uses the halo distributions directly. We apply both techniques to one high-resolution N-body simulation and reconstruct the filamentary/sheet like network of the dark matter density field. We focus on investigating the properties of the dark matter halos inside these structures, in particular, on the directions of their spins and the orientation of their shapes with respect to the directions of the filaments and sheets. We find that both the spin and the major axes of filament halos with masses approx<10{sup 13} h {sup -1} M{sub sun} are preferentially aligned with the direction of the filaments. The spins and major axes of halos in sheets tend to lie parallel to the sheets. There is an opposite mass dependence of the alignment strength for the spin (negative) and major (positive) axes, i.e. with increasing halo mass the major axis tends to be more strongly aligned with the direction of the filament, whereas the alignment between halo spin and filament becomes weaker with increasing halo mass. The alignment strength as a function of the distance to the most massive node halo indicates that there is a transit large-scale environment impact: from the two-dimensional collapse phase of the filament to the three-dimensional collapse phase of the cluster/node halo at small separation. Overall, the two algorithms for filament/sheet identification investigated here agree well with each other. The method based on halos alone can be easily adapted for use with observational data sets.

Zhang Youcai; Yang Xiaohu; Lin Weipeng [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Partner Group of MPA, Nandan Road 80, Shanghai 200030 (China); Faltenbacher, Andreas; Springel, Volker [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Strasse 1, 85748 Garching (Germany); Wang Huiyuan, E-mail: yczhang@shao.ac.c [Key Laboratory for Research in Galaxies and Cosmology, Center for Astrophysics, University of Science and Technology of China, 230026 (China)

2009-11-20T23:59:59.000Z

159

On the Formation of Galaxy Halos: Comparing NGC 5128 and the Local Group Members  

E-Print Network [OSTI]

The metallicity distribution function (MDF) for the old red-giant stars in the halo of NGC 5128, the nearest giant elliptical galaxy, is virtually identical with the MDF for the old-disk stars in the LMC and also strongly resembles the halo MDF in M31. These galaxies all have high mean halo metallicities ( ~ -0.4$) with very small proportions of low-metallicity stars. These observations reinforce the view that metal-rich halos are quite normal for large galaxies of all types. Such systems are unlikely to have built up by accretion of pre-existing, gas-free small satellite galaxies, unless these satellites had an extremely shallow mass distribution (d log N / d log M > -1). We suggest that the halo of NGC 5128 is more likely to have assembled from hierarchical merging of gas-rich lumps in which the bulk of star formation took place during or after the merger stage.

W. E. Harris; G. L. H. Harris

2001-08-14T23:59:59.000Z

160

CN ANOMALIES IN THE HALO SYSTEM AND THE ORIGIN OF GLOBULAR CLUSTERS IN THE MILKY WAY  

SciTech Connect (OSTI)

We explore the kinematics and orbital properties of a sample of red giants in the halo system of the Milky Way that are thought to have formed in globular clusters based on their anomalously strong UV/blue CN bands. The orbital parameters of the CN-strong halo stars are compared to those of the inner- and outer-halo populations as described by Carollo et al., and to the orbital parameters of globular clusters with well-studied Galactic orbits. The CN-strong field stars and the globular clusters both exhibit kinematics and orbital properties similar to the inner-halo population, indicating that stripped or destroyed globular clusters could be a significant source of inner-halo field stars, and suggesting that both the CN-strong stars and the majority of globular clusters are primarily associated with this population.

Carollo, Daniela [Department of Physics and Astronomy-Astronomy, Astrophysics and Astrophotonic Research Center Macquarie University-North Ryde, 2109 NSW (Australia); Martell, Sarah L. [Australian Astronomical Observatory, North Ryde, 2109 NSW (Australia); Beers, Timothy C. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Freeman, Ken C., E-mail: daniela.carollo@mq.edu.au, E-mail: smartell@aao.gov.au, E-mail: beers@noao.edu, E-mail: kcf@mso.anu.edu.au [Research School of Astronomy and Astrophysics, Australian National University and Mount Stromlo Observatory, Cotter Road, Weston, ACT 2611 (Australia)

2013-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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

Semi-empirical catalog of early-type galaxy-halo systems: dark matter density profiles, halo contraction and dark matter annihilation strength  

SciTech Connect (OSTI)

With Sloan Digital Sky Survey galaxy data and halo data from up-to-date N-body simulations within the ?CDM framework we construct a semi-empirical catalog (SEC) of early-type galaxy-halo systems by making a self-consistent bivariate statistical match of stellar mass (M{sub *}) and velocity dispersion (?) with halo virial mass (M{sub vir}) as demonstrated here for the first time. We then assign stellar mass profile and velocity dispersion profile parameters to each system in the SEC using their observed correlations with M{sub *} and ?. Simultaneously, we solve for dark matter density profile of each halo using the spherical Jeans equation. The resulting dark matter density profiles deviate in general from the dissipationless profile of Navarro-Frenk-White or Einasto and their mean inner density slope and concentration vary systematically with M{sub vir}. Statistical tests of the distribution of profiles at fixed M{sub vir} rule out the null hypothesis that it follows the distribution predicted by dissipationless N-body simulations for M{sub vir}?<10{sup 13.5} {sup } {sup 14.5} M{sub s}un. These dark matter profiles imply that dark matter density is, on average, enhanced significantly in the inner region of halos with M{sub vir}?<10{sup 13.5} {sup } {sup 14.5} M{sub s}un supporting halo contraction. The main characteristics of halo contraction are: (1) the mean dark matter density within the effective radius has increased by a factor varying systematically up to ? 34 at M{sub vir} = 10{sup 12} M{sub s}un, and (2) the inner density slope has a mean of (?) ? 1.3 with ?{sub dm}(r)?r{sup ??} and a halo-to-halo rms scatter of rms(?) ? 0.40.5 for 10{sup 12} M{sub s}un?halos of nearby elliptical and lenticular galaxies can, in principle, be promising targets for ?-ray emission from dark matter annihilation.

Chae, Kyu-Hyun [Department of Astronomy and Space Science, Sejong University, 98 Gunja-dong Gwangjin-Gu, Seoul 143-747 (Korea, Republic of); Kravtsov, Andrey V. [Kavli Institute for Cosmological Physics, The University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Frieman, Joshua A. [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Bernardi, Mariangela, E-mail: chae@sejong.ac.kr, E-mail: andrey@oddjob.uchicago.edu, E-mail: frieman@fnal.gov, E-mail: bernardm@physics.upenn.edu [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States)

2012-11-01T23:59:59.000Z

162

$^6$He nucleus in halo effective field theory  

E-Print Network [OSTI]

Background: In recent years properties of light rare isotopes have been measured with high accuracy. At the same time, the theoretical description of light nuclei has made enormous progress, and properties of, e.g., the Helium isotopes can now be calculated {\\it ab initio}. These advances make those rare isotopes an ideal testing ground for effective field theories (EFTs) built upon cluster degrees of freedom. Purpose: Systems with widely separated intrinsic scales are well suited to an EFT treatment. The Borromean halo nucleus $^6$He exhibits such a separation of scales. In this work an EFT in which the degrees of freedom are the valence neutrons ($n$) and an inert $^4$He-core ($\\alpha$) is employed. The properties of ${}^6$He can then be calculated using the momentum-space Faddeev equations for the $\\alpha nn$ bound state to obtain information on ${}^6$He at leading order (LO) within the EFT. Results: The $nn$ virtual state and the $^2$P$_{3/2}$ resonance in $^5$He give the two-body amplitudes which are input to our LO three-body Halo EFT calculation. We find that without a genuine three-body interaction the two-neutron separation energy $S_{2n}$ of ${}^6$He is strongly cutoff dependent. We introduce a $nn \\alpha$ "three-body" operator which renormalizes the system, adjusting its coefficient to reproduce the $S_{2n}$ of $^6$He. The Faddeev components are then cutoff independent for cutoffs of the order of, and above, the breakdown scale of the Halo EFT. Conclusions: As in the case of a three-body system where only resonant s-wave interactions are present, one three-body input is required for the renormalization of the EFT equations that describe $^6$He at LO. However, in contrast to the s-wave-only case, the running of the LO $nn\\alpha$ counterterm does not exhibit discrete scale invariance, due to the presence of the p-wave $n\\alpha$ interaction.

C. Ji; Ch. Elster; D. R. Phillips

2014-11-03T23:59:59.000Z

163

DARK MATTER HALO PROFILES OF MASSIVE CLUSTERS: THEORY VERSUS OBSERVATIONS  

SciTech Connect (OSTI)

Dark-matter-dominated cluster-scale halos act as an important cosmological probe and provide a key testing ground for structure formation theory. Focusing on their mass profiles, we have carried out (gravity-only) simulations of the concordance {Lambda}CDM cosmology, covering a mass range of 2 Multiplication-Sign 10{sup 12} to 2 Multiplication-Sign 10{sup 15} h {sup -1} M{sub Sun} and a redshift range of z = 0-2, while satisfying the associated requirements of resolution and statistical control. When fitting to the Navarro-Frenk-White profile, our concentration-mass (c-M) relation differs in normalization and shape in comparison to previous studies that have limited statistics in the upper end of the mass range. We show that the flattening of the c-M relation with redshift is naturally expressed if c is viewed as a function of the peak height parameter, {nu}. Unlike the c-M relation, the slope of the c-{nu} relation is effectively constant over the redshift range z = 0-2, while the amplitude varies by {approx}30% for massive clusters. This relation is, however, not universal: using a simulation suite covering the allowed wCDM parameter space, we show that the c-{nu} relation varies by about {+-}20% as cosmological parameters are varied. At fixed mass, the c(M) distribution is well fit by a Gaussian with {sigma}{sub c}/(c) {approx_equal} 1/3, independent of the radius at which the concentration is defined, the halo dynamical state, and the underlying cosmology. We compare the {Lambda}CDM predictions with observations of halo concentrations from strong lensing, weak lensing, galaxy kinematics, and X-ray data, finding good agreement for massive clusters (M{sub vir} > 4 Multiplication-Sign 10{sup 14} h {sup -1} M{sub Sun }), but with some disagreements at lower masses. Because of uncertainty in observational systematics and modeling of baryonic physics, the significance of these discrepancies remains unclear.

Bhattacharya, Suman; Habib, Salman; Heitmann, Katrin [High Energy Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States)] [High Energy Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Vikhlinin, Alexey [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2013-03-20T23:59:59.000Z

164

Antibound States and Halo Formation in the Gamow Shell Model  

E-Print Network [OSTI]

The open quantum system formulation of the nuclear shell model, the so-called Gamow Shell Model (GSM), is a multi-configurational SM that employs a single-particle basis given by the Berggren ensemble consisting of Gamow states and the non-resonant continuum of scattering states. The GSM is of particular importance for weakly bound/unbound nuclear states where both many-body correlations and the coupling to decay channels are essential. In this context, we investigate the role of l=0 antibound (virtual) neutron single-particle states in the shell model description of loosely bound wave functions, such as the ground state wave function of a halo nucleus 11Li.

N. Michel; W. Nazarewicz; M. Ploszajczak; J. Rotureau

2006-09-07T23:59:59.000Z

165

The Flattened Dark Matter Halo of M31 as Deduced from the Observed HI Scale Heights  

E-Print Network [OSTI]

In this paper, we use the outer-galactic HI scale height data as well as the observed rotation curve as constraints to determine the halo density distribution of the Andromeda galaxy (M31). We model the galaxy as a gravitationally-coupled system of stars and gas, responding to the external force-field of a known Hernquist bulge and the dark matter halo, the density profile of the latter being characterized by four free parameters. The parameter space of the halo is optimized so as to match the observed HI thickness distribution as well as the rotation curve on an equal footing, unlike the previous studies of M31 which were based on rotation curves alone. We show that an oblate halo, with an isothermal density profile, provides the best fit to the observed data. This gives a central density of 0.011 M_sun /pc^3, a core radius of 21 kpc, and an axis ratio of 0.4. The main result from this work is the flattened dark matter halo for M31, which is required to match the outer galactic HI scale height data. Interestingly, such flattened halos lie at the most oblate end of the distribution of halo shapes found in recent cosmological simulations.

Arunima Banerjee; Chanda J. Jog

2008-06-23T23:59:59.000Z

166

Internal Alignments of Red Versus Blue Discs in Dark Matter Halos  

E-Print Network [OSTI]

Large surveys have shown that red galaxies are preferentially aligned with their halos while blue galaxies have a more isotropic distribution. Since halos generally align with their filaments this introduces a bias in the measurement of the cosmic shear from weak lensing. It is therefore vitally important to understand why this difference arises. We explore the stability of different disc orientations within triaxial halos. We show that, in the absence of gas, the disc orientation is most stable when its spin is along the minor axis of the halo. Instead when gas cools onto a disc it is able to form in almost arbitrary orientation, including off the main planes of the halo (but avoiding an orientation perpendicular to the halo's intermediate axis). Substructure helps gasless galaxies reach alignment with the halo faster, but have less effect on galaxies when gas is cooling onto the disc. Our results provide a novel and natural interpretation for why red, gas poor galaxies are preferentially aligned with their ...

Debattista, Victor P; Roskar, Rok; Quinn, Thomas; Moore, Ben; Cole, David R

2015-01-01T23:59:59.000Z

167

A Two-Parameter Matching Scheme for Massive Galaxies and Dark Matter Haloes  

E-Print Network [OSTI]

Halo Abundance Matching has been used to construct a one-parameter mapping between galaxies and dark matter haloes by assuming that halo mass and galaxy luminosity (or stellar mass) are monotonically related. While this approach has been reasonably successful, it is known that galaxies must be described by at least two parameters, as can be seen from the two-parameter Fundamental Plane on which massive early-type galaxies lie. In this paper, we derive a connection between initial dark matter density perturbations in the early universe and present-day virialized dark matter haloes by assuming simple spherical collapse combined with conservation of mass and energy. We find that $z = 0$ halo concentration, or alternatively the inner slope of the halo density profile $\\alpha$, is monotonically and positively correlated with the collapse redshift of the halo. This is qualitatively similar to the findings of some previous works based on numerical simulations, with which we compare our results. We then describe how ...

Kulier, Andrea

2015-01-01T23:59:59.000Z

168

Comparing Light Bulbs  

Broader source: Energy.gov [DOE]

In this exercise, students will use a light to demonstrate the difference between being energy-efficient and energy-wasteful, and learn what energy efficiency means.

169

INVESTIGATION OF THE TOTAL ORGANIC HALOGEN ANALYTICAL METHOD AT THE WASTE SAMPLING CHARACTERIZATION FACILITY (WSCF)  

SciTech Connect (OSTI)

Total organic halogen (TOX) is used as a parameter to screen groundwater samples at the Hanford Site. Trending is done for each groundwater well, and changes in TOX and other screening parameters can lead to costly changes in the monitoring protocol. The Waste Sampling and Characterization Facility (WSCF) analyzes groundwater samples for TOX using the United States Environmental Protection Agency (EPA) SW-846 method 9020B (EPA 1996a). Samples from the Soil and Groundwater Remediation Project (S&GRP) are submitted to the WSCF for analysis without information regarding the source of the sample; each sample is in essence a 'blind' sample to the laboratory. Feedback from the S&GRP indicated that some of the WSCF-generated TOX data from groundwater wells had a number of outlier values based on the historical trends (Anastos 2008a). Additionally, analysts at WSCF observed inconsistent TOX results among field sample replicates. Therefore, the WSCF lab performed an investigation of the TOX analysis to determine the cause of the outlier data points. Two causes were found that contributed to generating out-of-trend TOX data: (1) The presence of inorganic chloride in the groundwater samples: at inorganic chloride concentrations greater than about 10 parts per million (ppm), apparent TOX values increase with increasing chloride concentration. A parallel observation is the increase in apparent breakthrough of TOX from the first to the second activated-carbon adsorption tubes with increasing inorganic chloride concentration. (2) During the sample preparation step, excessive purging of the adsorption tubes with oxygen pressurization gas after sample loading may cause channeling in the activated-carbon bed. This channeling leads to poor removal of inorganic chloride during the subsequent wash step with aqueous potassium nitrate. The presence of this residual inorganic chloride then produces erroneously high TOX values. Changes in sample preparation were studied to more effectively remove inorganic chloride from the activated carbon adsorption tubes. With the TOX sample preparation equipment and TOX analyzers at WSCF, the nitrate wash recommended by EPA SW-846 method 9020B was found to be inadequate to remove inorganic chloride interference. Increasing the nitrate wash concentration from 10 grams per liter (g/L) to 100 g/L potassium nitrate and increasing the nitrate wash volume from 3 milliliters (mL) to 10 mL effectively removed the inorganic chloride up to at least 100 ppm chloride in the sample matrix. Excessive purging of the adsorption tubes during sample preparation was eliminated. These changes in sample preparation have been incorporated in the analytical procedure. The results using the revised sample preparation procedure show better agreement of TOX values both for replicate analyses of single samples and for the analysis of replicate samples acquired from the same groundwater well. Furthermore, less apparent column breakthrough now occurs with the revised procedure. One additional modification made to sample preparation was to discontinue the treatment of groundwater samples with sodium bisulfite. Sodium bisulfite is used to remove inorganic chlorine from the sample; inorganic chlorine is not expected to be a constituent in these groundwater samples. Several other factors were also investigated as possible sources of anomalous TOX results: (1) Instrument instability: examination of the history of results for TOX laboratory control samples and initial calibration verification standards indicate good long-term precision for the method and instrument. Determination of a method detection limit of 2.3 ppb in a deionized water matrix indicates the method and instrumentation have good stability and repeatability. (2) Non-linear instrument response: the instrument is shown to have good linear response from zero to 200 parts per billion (ppb) TOX. This concentration range encompasses the majority of samples received at WSCF for TOX analysis. (3) Improper sample preservation: ion-chromatographic analysis of several samples wit

DOUGLAS JG; MEZNARICH HD, PHD; OLSEN JR; ROSS GA; STAUFFER M

2008-09-30T23:59:59.000Z

170

INVESTIGATION OF THE TOTAL ORGANIC HALOGEN ANALYTICAL METHOD AT THE WASTE SAMPLING AND CHARACTERIZATION FACILITY  

SciTech Connect (OSTI)

Total organic halogen (TOX) is used as a parameter to screen groundwater samples at the Hanford Site. Trending is done for each groundwater well, and changes in TOX and other screening parameters can lead to costly changes in the monitoring protocol. The Waste Sampling and Characterization Facility (WSCF) analyzes groundwater samples for TOX using the United States Environmental Protection Agency (EPA) SW-S46 method 9020B (EPA 1996a). Samples from the Soil and Groundwater Remediation Project (SGRP) are submitted to the WSCF for analysis without information regarding the source of the sample; each sample is in essence a ''blind'' sample to the laboratory. Feedback from the SGRP indicated that some of the WSCF-generated TOX data from groundwater wells had a number of outlier values based on the historical trends (Anastos 200Sa). Additionally, analysts at WSCF observed inconsistent TOX results among field sample replicates. Therefore, the WSCF lab performed an investigation of the TOX analysis to determine the cause of the outlier data points. Two causes were found that contributed to generating out-of-trend TOX data: (1) The presence of inorganic chloride in the groundwater samples: at inorganic chloride concentrations greater than about 10 parts per million (ppm), apparent TOX values increase with increasing chloride concentration. A parallel observation is the increase in apparent breakthrough of TOX from the first to the second activated-carbon adsorption tubes with increasing inorganic chloride concentration. (2) During the sample preparation step, excessive purging of the adsorption tubes with oxygen pressurization gas after sample loading may cause channeling in the activated carbon bed. This channeling leads to poor removal of inorganic chloride during the subsequent wash step with aqueous potassium nitrate. The presence of this residual inorganic chloride then produces erroneously high TOX values. Changes in sample preparation were studied to more effectively remove inorganic chloride from the activated-carbon adsorption tubes. With the TOX sample preparation equipment and TOX analyzers at WSCF, the nitrate wash recommended by EPA SW-846 method 9020B was found to be inadequate to remove inorganic chloride interference. Increasing the nitrate wash concentration from 10 grams per liter (g/L) to 100 giL potassium nitrate and increasing the nitrate wash volume from 3 milliliters (mL) to 10 mL effectively removed the inorganic chloride up to at least 100 ppm chloride in the sample matrix. Excessive purging of the adsorption tubes during sample preparation was eliminated. These changes in sample preparation have been incorporated in the analytical procedure. The results using the revised sample preparation procedure show better agreement of TOX values both for replicate analyses of single samples and for the analysis of replicate samples acquired from the same groundwater well. Furthermore, less apparent adsorption tube breakthrough now occurs with the revised procedure. One additional modification made to sample preparation was to discontinue the treatment of groundwater samples with sodium bisulfite. Sodium bisulfite is used to remove inorganic chlorine from the sample; inorganic chlorine is not expected to be a constituent in these groundwater samples. Several other factors were also investigated as possible sources of anomalous TOX results: (1) Instrument instability: examination of the history of results for TOX laboratory control samples and initial calibration verification standards indicate good long-term precision for the method and instrument. Determination of a method detection limit of 2.3 ppb in a deionized water matrix indicates the method and instrumentation have good stability and repeatability. (2) Non-linear instrument response: the instrument is shown to have good linear response from zero to 200 parts per billion (ppb) TOX. This concentration range encompasses the majority of samples received at WSCF for TOX analysis. Linear response was checked using both non-volatile TOX species (trichlorophenol) an

JG DOUGLAS; HK MEZNARICH, PHD; JR OLSEN; GA ROSS PHD; M STAUFFER

2009-02-13T23:59:59.000Z

171

Impacts of halogen additions on mercury oxidation, in a slipstream selective catalyst reduction (SCR), reactor when burning sub-bituminous coal  

SciTech Connect (OSTI)

This paper presents a comparison of impacts of halogen species on the elemental mercury (Hg(0)) oxidation in a real coal-derived flue gas atmosphere. It is reported there is a higher percentage of Hg(0) in the flue gas when burning sub-bituminous coal (herein Powder River Basin (PRB) coal) and lignite, even with the use of selective catalytic reduction (SCR). The higher Hg(0) concentration in the flue gas makes it difficult to use the wet-FGD process for the mercury emission control in coal-fired utility boilers. Investigation of enhanced Hg(0) oxidation by addition of hydrogen halogens (HF, HCl, HBr, and HI) was conducted in a slipstream reactor with and without SCR catalysts when burning PRB coal. Two commercial SCR catalysts were evaluated. SCR catalyst no. 1 showed higher efficiencies of both NO reduction and Hg(0) oxidation than those of SCR catalyst no. 2. NH{sub 3} addition seemed to inhibit the Hg(0) oxidation, which indicated competitive processes between NH{sub 3} reduction and Hg(0) oxidation on the surface of SCR catalysts. The hydrogen halogens, in the order of impact on Hg(0) oxidation, were HBr, HI, and HCl or HF. Addition of HBr at approximately 3 ppm could achieve 80% Hg(0) oxidation. Addition of HI at approximately 5 ppm could achieve 40% Hg(0) oxidation. In comparison to the empty reactor, 40% Hg(0) oxidation could be achieved when HCl addition was up to 300 ppm. The enhanced Hg(0) oxidation by addition of HBr and HI seemed not to be correlated to the catalytic effects by both evaluated SCR catalysts. The effectiveness of conversion of hydrogen halogens to halogen molecules or interhalogens seemed to be attributed to their impacts on Hg(0) oxidation. 30 refs., 4 figs.

Yan Cao; Zhengyang Gao; Jiashun Zhu; Quanhai Wang; Yaji Huang; Chengchung Chiu; Bruce Parker; Paul Chu; Wei-ping Pan [Western Kentucky University (WKU), Bowling Green, KY (United States). Institute for Combustion Science and Environmental Technology (ICSET)

2008-01-01T23:59:59.000Z

172

Axial Ratio of Edge-On Spiral Galaxies as a Test For Extended Bright Radio Halos  

E-Print Network [OSTI]

We use surface brightness contour maps of nearby edge-on spiral galaxies to determine whether extended bright radio halos are common. In particular, we test a recent model of the spatial structure of the diffuse radio continuum by Subrahmanyan and Cowsik which posits that a substantial fraction of the observed high-latitude surface brightness originates from an extended Galactic halo of uniform emissivity. Measurements of the axial ratio of emission contours within a sample of normal spiral galaxies at 1500 MHz and below show no evidence for such a bright, extended radio halo. Either the Galaxy is atypical compared to nearby quiescent spirals or the bulk of the observed high-latitude emission does not originate from this type of extended halo.

Singal, J; Jones, E; Dunlap, H

2015-01-01T23:59:59.000Z

173

Possible features of galactic halo with electric field and observational constraints  

E-Print Network [OSTI]

Observed rotational curves of neutral hydrogen clouds strongly support the fact that galactic halo contains huge amount of nonluminous matter, the so called gravitational dark matter. The nature of dark matter is a point of debate among the researchers. Recent observations reported the presence of ions of O, S, C, Si etc in the galactic halo and intergalactic medium. This supports the possibility of existence of electric field in the galactic halo region. We therefore propose a model of galactic halo considering this electric field arising due to charged particles as one of the inputs for the background spacetime metric. Considering dark matter as an anisotropic fluid we obtain the expressions for energy density and pressure of dark matter there and consequently the equation of state of dark matter. Various other aspects of the solutions are also analyzed along with a critical comparison with and constraints of different observational evidences.

Koushik Chakraborty; Farook Rahaman; Saibal Ray; Arka Nandi; Nasarul Islam

2014-12-15T23:59:59.000Z

174

Observations and Modeling of the Disk-Halo Interaction in our Galaxy  

E-Print Network [OSTI]

Galaxies are surrounded by large halos of hot gas which must be replenished as the gas cools. This led Norman & Ikeuchi (1989) to propose the chimney model of the interstellar medium, which predicts that there should be on the order of a thousand such conduits connecting the disk and the halo of a galaxy. Where then are these structures and other possible disk-halo connections in our galaxy? What do they look like, how can we detect them, and what do they tell us about the interstellar medium and about the Galaxy? We present a review of the observational evidence for Galactic disk-halo connections, beginning with large scale searches and then concentrating on the characteristics of selected candidates. We summarize how modeling these structures can provide information on the structure of the interstellar medium in which they evolved, focusing on the W4 superbubble and the Anchor as illustrations.

Magdalen Normandeau; Shantanu Basu

1998-11-15T23:59:59.000Z

175

Chandra Observations of ULIRGs: Extended Hot Gas Halos in Merging Galaxies  

E-Print Network [OSTI]

We study the properties of hot gaseous halos in 10 nearby ultraluminous IRAS galaxies observed with the ACIS instrument on board Chandra. For all sample galaxies, diffuse soft X-ray emissions are found within ~10 kpc of the central region; their spectra are well fitted by a MEKAL model plus emission lines from alpha-elements and other ions. The temperature of the hot gas is about 0.7 keV and metallicity is about 1 solar. Outside the central region, extended hot gaseous halos are found for nine out of the ten ULIRGs. Most spectra of these extended halos can be fitted with a MEKAL model with a temperature of about 0.6 keV and a low metallicity (~ 0.1 solar). We discuss the implications of our results on the origin of X-ray halos in elliptical galaxies and the feedback processes associated with starbursts.

Z. Y. Huo; X. Y. Xia; S. J. Xue; S. Mao; Z. G. Deng

2004-05-09T23:59:59.000Z

176

Limits on Hot Galactic Halo Gas from X-ray Absorption Lines  

E-Print Network [OSTI]

Although the existence of large-scale hot gaseous halos around massive disk galaxies has been theorized for a long time, there is yet very little observational evidence. We report the Chandra and XMM-Newton grating spectral ...

Yao, Yangsen

177

The effect of spin-orbit splitting on the association kinetics of barrierless halogen atom-hydrocarbon radical reactions.  

SciTech Connect (OSTI)

The effect of the geometry dependence of spin-orbit splitting on transition state theory (TST) predictions for radical-radical recombination rate coefficients is examined. The effects are illustrated with direct ab initio variable-reaction-coordinate (VRC)-TST calculations for the reactions of two types of hydrocarbon radicals (R = CH{sub 3} and CH{sub 2}CHCH{sub 2}) with three halogen atoms (X = F, Cl, and Br). These halogen atoms exhibit a range of spin-orbit interaction strengths, while their interactions with the two hydrocarbon radicals exhibit a range of attractiveness. The transition state dividing surfaces for these barrierless reactions occur over a range of R-X fragment separations ({approx}3-7 {angstrom}) where the magnitude of the spin-orbit splitting is strongly geometry dependent. Perturbative models for incorporating the energetic effect of spin-orbit splitting into barrierless kinetics are presented and tested. Simply neglecting the variation in the spin-orbit splitting is demonstrated to contribute an error of less than 15% to the predicted rate coefficients for all but the CH{sub 2}CHCH{sub 2} + Br reaction, where its neglect increases the rate by up to a factor of 2. For the CH{sub 2}CHCH{sub 2} + Br reaction, the effect of spin-orbit splitting is not perturbative and instead qualitatively changes the long-range interaction potential and association dynamics. The present theoretical predictions are compared with available experimental measurements and previous theoretical work. For the CH{sub 3} + F association reaction, the errors associated with limitations in the basis set and in the active space are studied, and a detailed comparison is made between VRC-TST and rigid rotor-harmonic oscillator variational TST.

Jasper, A. W.; Klippenstein, S. J.; Harding, L. B. (Chemical Sciences and Engineering Division); (SNL)

2010-01-01T23:59:59.000Z

178

Origin of the metallicity distribution of the NGC 5128 stellar halo  

E-Print Network [OSTI]

Recent {\\it Hubble Space Telescope} photometry in the nearby elliptical galaxy NGC 5128 shows that its halo field star population is dominated by moderately metal-rich stars, with a peak at [m/H] $\\simeq$ -0.4 and with a very small fraction of metal-poor ([m/H] $<$ -1.0) stars. In order to investigate the physical processes which may have produced this metallicity distribution function (MDF), we consider a model in which NGC 5128 is formed by merging of two major spiral galaxies. We find that the halo of an elliptical formed this way is predominantly populated by moderately metal-rich stars with [m/H] $\\sim$ -0.4 which were initially within the outer parts of the two merging discs and were tidally stripped during the merger. To match the NGC 5128 data, we find that the progenitor spiral discs must have rather steep metallicity gradients similar to the one defined by the Milky Way open clusters, as well as sparse metal-poor haloes (5% or less of the disc mass). Very few stars from the central bulges of the spiral galaxies end up in the halo, so the results are not sensitive to the relative sizes (bulge-to-disc ratios) or metallicities of the initial bulges. Finally, we discuss the effects on the globular cluster system (GCS). The emergent elliptical will end up with metal-poor halo clusters from the original spiral haloes, but with moderately metal-rich halo stars from the progenitor discs, thus creating a mean offset between the MDFs of the halo stars and the GCS.

Kenji Bekki; William E. Harris; Gretchen L. H. Harris

2002-12-27T23:59:59.000Z

179

Halo-Independent analysis of direct dark matter detection data for any WIMP interaction  

E-Print Network [OSTI]

The halo independent comparison of direct dark matter detection data eliminates the need to make any assumption on the uncertain local dark matter distribution and is complementary to the usual data comparison which required assuming a dark halo model for our galaxy. The method, initially proposed for WIMPs with spin-independent contact interactions, has been generalized to any other interaction and applied to recent data on "Light WIMPs".

Graciela B. Gelmini

2014-11-04T23:59:59.000Z

180

NOT DEAD YET: COOL CIRCUMGALACTIC GAS IN THE HALOS OF EARLY-TYPE GALAXIES  

SciTech Connect (OSTI)

We report new observations of circumgalactic gas in the halos of early-type galaxies (ETGs) obtained by the COS-Halos Survey with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. We find that detections of H I surrounding ETGs are typically as common and strong as around star-forming galaxies, implying that the total mass of circumgalactic material is comparable in the two populations. For ETGs, the covering fraction for H I absorption above 10{sup 16} cm{sup -2} is {approx}40%-50% within {approx}150 kpc. Line widths and kinematics of the detected material show it to be cold (T {approx}< 10{sup 5} K) in comparison to the virial temperature of the host halos. The implied masses of cool, photoionized circumgalactic medium baryons may be up to 10{sup 9}-10{sup 11} M{sub Sun }. Contrary to some theoretical expectations, strong halo H I absorbers do not disappear as part of the quenching of star formation. Even passive galaxies retain significant reservoirs of halo baryons that could replenish the interstellar gas reservoir and eventually form stars. This halo gas may feed the diffuse and molecular gas that is frequently observed inside ETGs.

Thom, Christopher; Tumlinson, Jason; Sembach, Kenneth R. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Werk, Jessica K.; Xavier Prochaska, J. [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Oppenheimer, Benjamin D. [Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands); Peeples, Molly S. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095 (United States); Tripp, Todd M.; Katz, Neal S. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003-9305 (United States); O'Meara, John M. [Department of Chemistry and Physics, Saint Michael's College, Colchester, VT 05439 (United States); Ford, Amanda Brady; Dave, Romeel [Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Weinberg, David H. [Department of Astronomy, Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States)

2012-10-20T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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

The Dependence of the Mass Assembly History of Cold Dark Matter Halos on Environment  

E-Print Network [OSTI]

We show by means of a high-resolution N-body simulation how the mass assembly histories of galaxy-size cold dark matter (CDM) halos depend on environment. Halos in high density environments form earlier and a higher fraction of their mass is assembled in major mergers, compared to low density environments. The distribution of the present-day specific mass aggregation rate is strongly dependent on environment. While in low density environments only ~20% of the halos are not accreting mass at the present epoch, this fraction rises to ~80% at high densities. At z=1 the median of the specific aggregation rate is ~4 times larger than at z=0 and almost independent on environment. All the dependences on environment found here are critically enhanced by local processes associated to subhalos because the fraction of subhalos increases as the environment gets denser. The distribution of the halo specific mass aggregation rate as well as its dependence on environment resemble the relations for the specific star formation rate distribution of galaxies. An analogue of the morphology-density relation is also present at the level of CDM halos, being driven by the halo major merging history. Nevertheless, baryonic processes are necessary in order to explain further details and the evolution of the star formation rate-, color- and morphology-environment relations.

C. Maulbetsch; V. Avila-Reese; P. Colin; S. Gottloeber; A. Khalatyan; M. Steinmetz

2006-09-23T23:59:59.000Z

182

The Peculiar Behavior of Halo Coronal Mass Ejections in Solar Cycle 24  

E-Print Network [OSTI]

We report on a remarkable finding that the halo coronal mass ejections (CMEs) in cycle 24 are more abundant than in cycle 23, although the sunspot number in cycle 24 has dropped by about 40%. We also find that the distribution of halo-CME source locations is different in cycle 24: the longitude distribution of halos is much flatter with the number of halos originating at central meridian distance >/=60 degrees twice as large as that in cycle 23. On the other hand, the average speed and the associated soft X-ray flare size are the same in the two cycles, suggesting that the ambient medium into which the CMEs are ejected is significantly different. We suggest that both the higher abundance and larger central meridian longitudes of halo CMEs can be explained as a consequence of the diminished total pressure in the heliosphere in cycle 24 (Gopalswamy et al. 2014). The reduced total pressure allows CMEs expand more than usual making them appear as halos.

Gopalswamy, N; Akiyama, S; Mkel, P; Yashiro, S; Michalek, G

2015-01-01T23:59:59.000Z

183

Direct collapse black hole formation from synchronized pairs of atomic cooling halos  

E-Print Network [OSTI]

High-redshift quasar observations imply that supermassive black holes (SMBHs) larger than $\\sim 10^9 ~ M_\\odot$ formed before $z=6$. That such large SMBHs formed so early in the Universe remains an open theoretical problem. One possibility is that gas in atomic cooling halos exposed to strong Lyman-Werner (LW) radiation forms $10^4-10^6 ~ M_\\odot$ supermassive stars which quickly collapse into black holes. We propose a scenario for direct collapse black hole (DCBH) formation based on synchronized pairs of pristine atomic cooling halos. We consider halos at very small separation with one halo being a subhalo of the other. The first halo to surpass the atomic cooling threshold forms stars. Soon after these stars are formed, the other halo reaches the cooling threshold and due to its small distance from the newly formed galaxy, is exposed to the critical LW intensity required to form a DCBH. The main advantage of this scenario is that synchronization can potentially prevent photoevaporation and metal pollution i...

Visbal, Eli; Bryan, Greg L

2014-01-01T23:59:59.000Z

184

Voids in the Local Volume: a limit on appearance of a galaxy in a DM halo  

E-Print Network [OSTI]

Current explanation of the overabundance of dark matter subhalos in the Local Group (LG) indicates that there maybe a limit on mass of a halo, which can host a galaxy. This idea can be tested using voids in the distribution of galaxies: at some level small voids should not contain any (even dwarf) galaxies. We use observational samples complete to M_B = -12 with distances less than 8 Mpc to construct the void function (VF): the distribution of sizes of voids empty of any galaxies. There are ~30 voids with sizes ranging from 1 to 5 Mpc. We then study the distribution of dark matter halos in very high resolution simulations of the LCDM model. The theoretical VF matches the observations remarkably well only if we use halos with circular velocities larger than 45 +/- 10 km/s. This agrees with the Local Group predictions. There are smaller halos in the voids, but they should not produce any luminous matter. Small voids look quite similar to their giant cousins: the density has a minimum at the center of a void and it increases as we get closer to the border. Small nonluminous halos inside the void form a web of tiny filaments. Thus, both the Local Group data and the nearby voids indicate that isolated halos below 45 +/- 10 km/s must not host galaxies and that small (few Mpc) voids are truly dark.

Anton V. Tikhonov; Anatoly A. Klypin

2007-07-24T23:59:59.000Z

185

An Excursion Set Model of the Cosmic Web: the Abundance of Sheets, Filaments And Halos  

SciTech Connect (OSTI)

We discuss an analytic approach for modeling structure formation in sheets, filaments and knots. This is accomplished by combining models of triaxial collapse with the excursion set approach: sheets are defined as objects which have collapsed along only one axis, filaments have collapsed along two axes, and halos are objects in which triaxial collapse is complete. In the simplest version of this approach, which we develop here, large scale structure shows a clear hierarchy of morphologies: the mass in large-scale sheets is partitioned up among lower mass filaments, which themselves are made-up of still lower mass halos. Our approach provides analytic estimates of the mass fraction in sheets, filaments and halos, and its evolution, for any background cosmological model and any initial fluctuation spectrum. In the currently popular {Lambda}CDM model, our analysis suggests that more than 99% of the mass in sheets, and 72% of the mass in filaments, is stored in objects more massive than 10{sup 10}M{sub {circle_dot}} at the present time. For halos, this number is only 46%. Our approach also provides analytic estimates of how halo abundances at any given time correlate with the morphology of the surrounding large-scale structure, and how halo evolution correlates with the morphology of large scale structure.

Shen, Jiajian; /Penn State U., Astron. Astrophys.; Abel, Tom; /KIPAC, Menlo Park; Mo, Houjun; /Massachusetts U., Amherst; Sheth, Ravi; /Pennsylvania U.

2006-01-11T23:59:59.000Z

186

Gamma-ray halo around the M31 galaxy as seen by the Fermi LAT  

E-Print Network [OSTI]

Theories of galaxy formation predict the existence of extended gas halo around spiral galaxies. If there are 10-100 nG magnetic fields at several ten kpc distances from the galaxies, extended galactic cosmic ray (CR) haloes could also exist. Galactic CRs could interact with the tenuous hot halo gas to produce observable $\\gamma$-rays. In this paper we have performed search for such a halo around the M31 galaxy -- the closest large spiral galaxy. Our analysis of 5.5 years of the Fermi LAT data revealed the presence of a spatially extended emission excess around M31. The data can be fitted using the simplest morphology of a uniformly bright circle. The best fit gave a 4.4$\\sigma$ significance for a $3^{\\circ}$ (40 kpc) halo with photon flux of $\\sim (1.9\\pm1.1)\\times 10^{-9} ~\\mathrm{cm^{-2}s^{-1}}$ and luminosity $(8.4\\pm4.6)\\times 10^{38} ~\\mathrm{erg~s^{-1}}$ in the energy range 0.3--100 GeV. The presence of such a halo compellingly shows that a 10-100 nG magnetic field should extend around M31 up to a 40 kp...

Pshirkov, M S; Postnov, K A

2015-01-01T23:59:59.000Z

187

An excursion set model of the cosmic web: The abundance of sheets, filaments and halos  

E-Print Network [OSTI]

We discuss an analytic approach for modeling structure formation in sheets, filaments and knots. This is accomplished by combining models of triaxial collapse with the excursion set approach: sheets are defined as objects which have collapsed along only one axis, filaments have collapsed along two axes, and halos are objects in which triaxial collapse is complete. In the simplest version of this approach, which we develop here, large scale structure shows a clear hierarchy of morphologies: the mass in large-scale sheets is partitioned up among lower mass filaments, which themselves are made-up of still lower mass halos. Our approach provides analytic estimates of the mass fraction in sheets, filaments and halos, and its evolution, for any background cosmological model and any initial fluctuation spectrum. In the currently popular $\\Lambda$CDM model, our analysis suggests that more than 99% of the cosmic mass is in sheets, and 72% in filaments, with mass larger than $10^{10} M_{\\odot}$ at the present time. For halos, this number is only 46%. Our approach also provides analytic estimates of how halo abundances at any given time correlate with the morphology of the surrounding large-scale structure, and how halo evolution correlates with the morphology of large scale structure.

Jiajian Shen; Tom Abel; H. J. Mo; Ravi Sheth

2006-03-27T23:59:59.000Z

188

An Asymmetric Cone Model for Halo Coronal Mass Ejections  

E-Print Network [OSTI]

Due to projection effects, coronagraphic observations cannot uniquely determine parameters relevant to the geoeffectiveness of CMEs, such as the true propagation speed, width, or source location. The Cone Model for Coronal Mass Ejections (CMEs) has been studied in this respect and it could be used to obtain these parameters. There are evidences that some CMEs initiate from a flux-rope topology. It seems that these CMEs should be elongated along the flux-rope axis and the cross section of the cone base should be rather elliptical than circular. In the present paper we applied an asymmetric cone model to get the real space parameters of frontsided halo CMEs (HCMEs) recorded by SOHO/LASCO coronagraphs in 2002. The cone model parameters are generated through a fitting procedure to the projected speeds measured at different position angles on the plane of the sky. We consider models with the apex of the cone located at the center and surface of the Sun. The results are compared to the standard symmetric cone model.

G. Michalek

2007-10-24T23:59:59.000Z

189

The galactic halo in mixed dark matter cosmologies  

SciTech Connect (OSTI)

A possible solution to the small scale problems of the cold dark matter (CDM) scenario is that the dark matter consists of two components, a cold and a warm one. We perform a set of high resolution simulations of the Milky Way halo varying the mass of the WDM particle (m{sub WDM}) and the cosmic dark matter mass fraction in the WDM component ( f-bar {sub W}). The scaling ansatz introduced in combined analysis of LHC and astroparticle searches postulates that the relative contribution of each dark matter component is the same locally as on average in the Universe (e.g. f{sub W,s}un = f-bar {sub W}). Here we find however, that the normalised local WDM fraction (f{sub W,s}un / f-bar {sub W}) depends strongly on m{sub WDM} for m{sub WDM} < 1 keV. Using the scaling ansatz can therefore introduce significant errors into the interpretation of dark matter searches. To correct this issue a simple formula that fits the local dark matter densities of each component is provided.

Anderhalden, D.; Diemand, J.; Schneider, A. [Institute for Theoretical Physics, University of Zrich, Winterthurerst. 190, 8057 Zrich (Switzerland); Bertone, G. [GRAPPA Institute, University of Amsterdam, Science Park 904, 1090 GL Amsterdam (Netherlands); Macci, A.V., E-mail: donninoa@physik.uzh.ch, E-mail: diemand@physik.uzh.ch, E-mail: gf.bertone@gmail.com, E-mail: maccio@mpia.de, E-mail: aurel@physik.uzh.ch [Max-Planck-Insitute for Astronomy, Knigstuhl 17, 69117 Heidelberg (Germany)

2012-10-01T23:59:59.000Z

190

Linear response of galactic halos to adiabatic gravitational perturbations  

E-Print Network [OSTI]

We determine the response of a self-similar isothermal stellar system to small adiabatic gravitational perturbations. For odd spherical harmonics, the response is identical to the response of the analogous isothermal fluid system. For even spherical harmonics, the response can be regarded as an infinite series of wavetrains in $\\log r$, implying alternating compression and rarefaction in equal logarithmic radius intervals. Partly because of the oscillatory nature of the solutions, tidal fields from external sources are not strongly amplified by an intervening isothermal stellar system, except at radii $\\lta 10^{-3.5}$ times the satellite radius; at some radii the stellar system can even screen the external tidal field in a manner analogous to Debye screening. As Weinberg has pointed out, individual resonances in a stellar system can strongly amplify external tidal fields over a limited radial range, but we cannot address this possibility because we examine only adiabatic perturbations. We also discuss the application of our method to the halo response caused by the slow growth of an embedded thin disk.

Chigurupati Murali; Scott Tremaine

1997-09-14T23:59:59.000Z

191

The luminosity -- halo-mass relation for brightest cluster galaxies  

E-Print Network [OSTI]

We examine the central-galaxy luminosity -- host-halo mass relation for 54 Brightest Group Galaxies (BGGs) and 92 Brightest Cluster Galaxies (BCGs) at z<0.1 and present the first measurement of this relation for a sample of known BCGs at 0.1

Sarah Brough; Warrick Couch; Chris Collins; Doug Burke; Bob Mann

2008-01-08T23:59:59.000Z

192

Gamma Rays from Superheavy Relic Particles in the Halo  

E-Print Network [OSTI]

Superheavy (SH) quasistable particles generated in the Early Universe could be responsable for Ultra High Energy Cosmic Rays (UHECR) and be a component of Cold Dark Matter (CDM) in the universe. These particles are likely to cluster in the galactic halo, so that the main part of UHECR are gamma rays produced in the decay of neutral pions. Charged pions are also produced in the same process and result in high energy electrons. We consider here the production of gamma rays by synchrotron emission of these electrons in the galactic magnetic field. The gamma ray fluxes are in the region of interest for some current and proposed experiments (e.g. EGRET, GLAST, MILAGRO) in the energy range $0.1-10^4$ GeV. A comparison with the existing upper limits at $10^5-10^8$ GeV is also carried out. The detection of this flux of gamma rays would be an important signature of SH relic particles as sources of UHECR and would give a clue to the physics of the Early Universe.

Pasquale Blasi

1999-05-15T23:59:59.000Z

193

Testing gravity with halo density profiles observed through gravitational lensing  

SciTech Connect (OSTI)

We present a new test of the modified gravity endowed with the Vainshtein mechanism with the density profile of a galaxy cluster halo observed through gravitational lensing. A scalar degree of freedom in the galileon modified gravity is screened by the Vainshtein mechanism to recover Newtonian gravity in high-density regions, however it might not be completely hidden on the outer side of a cluster of galaxies. Then the modified gravity might yield an observational signature in a surface mass density of a cluster of galaxies measured through gravitational lensing, since the scalar field could contribute to the lensing potential. We investigate how the transition in the Vainshtein mechanism affects the surface mass density observed through gravitational lensing, assuming that the density profile of a cluster of galaxies follows the original Navarro-Frenk-White (NFW) profile, the generalized NFW profile and the Einasto profile. We compare the theoretical predictions with observational results of the surface mass density reported recently by other researchers. We obtain constraints on the amplitude and the typical scale of the transition in the Vainshtein mechanism in a subclass of the generalized galileon model.

Narikawa, Tatsuya; Yamamoto, Kazuhiro, E-mail: narikawa@theo.phys.sci.hiroshima-u.ac.jp, E-mail: kazuhiro@hiroshima-u.ac.jp [Department of Physical Science, Hiroshima University, Higashi-Hiroshima 739-8526 (Japan)

2012-05-01T23:59:59.000Z

194

Disk Contamination in a sample of proper motion selected halo stars: A Comment on "Direct Detection of Galactic Halo Dark Matter", B.A. Oppenheimer et al., Science  

E-Print Network [OSTI]

Based on a proper motion survey, Oppenheimer et al. claim the detection of a white dwarf component of the dark matter of the halo. I show that most of the white dwarfs in their sample are likely disk white dwarfs which have been previously detected, and represent no new population.

David S. Graff

2001-07-12T23:59:59.000Z

195

ACCURATE UNIVERSAL MODELS FOR THE MASS ACCRETION HISTORIES AND CONCENTRATIONS OF DARK MATTER HALOS  

SciTech Connect (OSTI)

A large amount of observations have constrained cosmological parameters and the initial density fluctuation spectrum to a very high accuracy. However, cosmological parameters change with time and the power index of the power spectrum dramatically varies with mass scale in the so-called concordance LAMBDACDM cosmology. Thus, any successful model for its structural evolution should work well simultaneously for various cosmological models and different power spectra. We use a large set of high-resolution N-body simulations of a variety of structure formation models (scale-free, standard CDM, open CDM, and LAMBDACDM) to study the mass accretion histories, the mass and redshift dependence of concentrations, and the concentration evolution histories of dark matter halos. We find that there is significant disagreement between the much-used empirical models in the literature and our simulations. Based on our simulation results, we find that the mass accretion rate of a halo is tightly correlated with a simple function of its mass, the redshift, parameters of the cosmology, and of the initial density fluctuation spectrum, which correctly disentangles the effects of all these factors and halo environments. We also find that the concentration of a halo is strongly correlated with the universe age when its progenitor on the mass accretion history first reaches 4% of its current mass. According to these correlations, we develop new empirical models for both the mass accretion histories and the concentration evolution histories of dark matter halos, and the latter can also be used to predict the mass and redshift dependence of halo concentrations. These models are accurate and universal: the same set of model parameters works well for different cosmological models and for halos of different masses at different redshifts, and in the LAMBDACDM case the model predictions match the simulation results very well even though halo mass is traced to about 0.0005 times the final mass, when cosmological parameters and the power index of the initial density fluctuation spectrum have changed dramatically. Our model predictions also match the PINOCCHIO mass accretion histories very well, which are much independent of our numerical simulations and our definitions of halo merger trees. These models are also simple and easy to implement, making them very useful in modeling the growth and structure of dark matter halos. We provide appendices describing the step-by-step implementation of our models. A calculator which allows one to interactively generate data for any given cosmological model is provided on the Web, together with a user-friendly code to make the relevant calculations and some tables listing the expected concentration as a function of halo mass and redshift in several popular cosmological models. We explain why LAMBDACDM and open CDM halos on nearly all mass scales show two distinct phases in their mass growth histories. We discuss implications of the universal relations we find in connection to the formation of dark matter halos in the cosmic density field.

Zhao, D. H.; Jing, Y. P. [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, CAS, 80 Nandan Road, Shanghai 200030 (China); Mo, H. J. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Boerner, G., E-mail: dhzhao@shao.ac.c [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Strasse 1, 85748 Garching (Germany)

2009-12-10T23:59:59.000Z

196

MAPPING THE STELLAR STRUCTURE OF THE MILKY WAY THICK DISK AND HALO USING SEGUE PHOTOMETRY  

SciTech Connect (OSTI)

We map the stellar structure of the Galactic thick disk and halo by applying color-magnitude diagram (CMD) fitting to photometric data from the Sloan Extension for Galactic Understanding and Exploration (SEGUE) survey. The SEGUE imaging scans allow, for the first time, a comprehensive analysis of Milky Way structure at both high and low latitudes using uniform Sloan Digital Sky Survey photometry. Incorporating photometry of all relevant stars simultaneously, CMD fitting bypasses the need to choose single tracer populations. Using old stellar populations of differing metallicities as templates, we obtain a sparse three-dimensional map of the stellar mass distribution at |Z|>1 kpc. Fitting a smooth Milky Way model comprising exponential thin and thick disks and an axisymmetric power-law halo allows us to constrain the structural parameters of the thick disk and halo. The thick-disk scale height and length are well constrained at 0.75 {+-} 0.07 kpc and 4.1 {+-} 0.4 kpc, respectively. We find a stellar halo flattening within {approx}25 kpc of c/a = 0.88 {+-} 0.03 and a power-law index of 2.75 {+-} 0.07 (for 7 kpc {approx_lt}R{sub GC} {approx_lt} 30 kpc). The model fits yield thick-disk and stellar halo densities at the solar location of {rho}{sub thick,sun} = 10{sup -2.3{+-}0.1} M{sub sun} pc{sup -3} and {rho}{sub halo,sun} = 10{sup -4.20{+-}0.05} M{sub sun} pc{sup -3}, averaging over any substructures. Our analysis provides the first clear in situ evidence for a radial metallicity gradient in the Milky Way's stellar halo: within R {approx_lt} 15 kpc the stellar halo has a mean metallicity of [Fe/H] {approx_equal} -1.6, which shifts to [Fe/H] {approx_equal} -2.2 at larger radii, in line with the two-component halo deduced by Carollo et al. from a local kinematic analysis. Subtraction of the best-fit smooth and symmetric model from the overall density maps reveals a wealth of substructures at all latitudes, some attributable to known streams and overdensities, and some new. A simple warp cannot account for the low latitude substructure, as overdensities occur simultaneously above and below the Galactic plane.

De Jong, Jelte T. A.; Rix, Hans-Walter; Martin, Nicolas F. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Yanny, Brian [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Dolphin, Andrew E. [Raytheon Company, 1151 East Hermans Road, Tucson, AZ 85756 (United States); Beers, Timothy C., E-mail: dejong@mpia.d [Department of Physics and Astronomy and JINA: Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824 (United States)

2010-05-01T23:59:59.000Z

197

Discovery, SAR, and Radiolabeling of Halogenated Benzimidazole Carboxamide Antagonists as Useful Tools for (alpha)4(beta)1 Integrin Expressed on T- and B-cell Lymphomas  

SciTech Connect (OSTI)

The cell surface receptor {alpha}{sub 4}{beta}{sub 1} integrin is an attractive yet poorly understood target for selective diagnosis and treatment of T- and B-cell lymphomas. This report focuses on the rapid microwave preparation of medicinally pertinent benzimidazole heterocycles, structure-activity relationships (SAR) of novel halobenzimidazole carboxamide antagonists 3-6, and preliminary biological evaluation of radioiodinated agents 7, 8, and 18. The I-125 derivative 18 had good tumor uptake (12 {+-} 1% ID/g at 24 h; 4.5 {+-} 1% ID/g at 48 h) and tumor:kidney ratio ({approx}4:1 at 24 h; 2.5:1 at 48 h) in xenograft murine models of B-cell lymphoma. Molecular homology models of {alpha}{sub 4}{beta}{sub 1} integrin have predicted that docked halobenzimidazole carboxamides have the halogen atom in a suitable orientation for halogen-hydrogen bonding. These high affinity ({approx} pM binding) halogenated ligands are attractive tools for medicinal and biological use; the fluoro and iodo derivatives are potential radiodiagnostic ({sup 18}F) or radiotherapeutic ({sup 131}I) agents, whereas the chloro and bromo analogues could provide structural insight into integrin-ligand interactions through photoaffinity cross-linking/mass spectroscopy experiments, as well as co-crystallization X-ray studies.

Carpenter, R D; Natarajan, A; Lau, E Y; Andrei, M; Solano, D M; Lightstone, F C; DeNardo, S J; Lam, K S; Kurth, M J

2010-02-08T23:59:59.000Z

198

Beam halo formation from space-charge dominated beams in uniform focusing channels  

SciTech Connect (OSTI)

In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which results in a 2-component beam consisting of an inner core and an outer halo. The halo is very prominent in mismatched beams, and the potential for accelerator activation is of concern for a next generation of cw, high-power proton linacs that could be applied for intense neutron generators to process nuclear materials. We present new results about beam halo and the evolution of space-charge dominated beams from multiparticle simulation of initial laminar beams in a uniform linear focusing channel, and from a model consisting of single particle interactions with a uniform-density beam core. We study the energy gain from particle interactions with the space-charge field of the core, and we identify the resonant characteristic of this interaction as the basic cause of the separation of the beam into the two components. We identify three different particle-trajectory types, and we suggest that one of these types may lead to continuous halo growth, even after the halo is removed by collimators.

O'Connell, J.S. (Booz, Allen and Hamilton, Inc., Arlington, VA (United States)); Wangler, T.P.; Mills, R.S. (Los Alamos National Lab., NM (United States)); Crandall, K.R. (AccSys Technology, Inc., Pleasanton, CA (United States))

1993-01-01T23:59:59.000Z

199

Beam halo formation from space-charge dominated beams in uniform focusing channels  

SciTech Connect (OSTI)

In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which results in a 2-component beam consisting of an inner core and an outer halo. The halo is very prominent in mismatched beams, and the potential for accelerator activation is of concern for a next generation of cw, high-power proton linacs that could be applied for intense neutron generators to process nuclear materials. We present new results about beam halo and the evolution of space-charge dominated beams from multiparticle simulation of initial laminar beams in a uniform linear focusing channel, and from a model consisting of single particle interactions with a uniform-density beam core. We study the energy gain from particle interactions with the space-charge field of the core, and we identify the resonant characteristic of this interaction as the basic cause of the separation of the beam into the two components. We identify three different particle-trajectory types, and we suggest that one of these types may lead to continuous halo growth, even after the halo is removed by collimators.

O`Connell, J.S. [Booz, Allen and Hamilton, Inc., Arlington, VA (United States); Wangler, T.P.; Mills, R.S. [Los Alamos National Lab., NM (United States); Crandall, K.R. [AccSys Technology, Inc., Pleasanton, CA (United States)

1993-06-01T23:59:59.000Z

200

VISITORS FROM THE HALO: 11 Gyr OLD WHITE DWARFS IN THE SOLAR NEIGHBORHOOD  

SciTech Connect (OSTI)

We report the discovery of three nearby old halo white dwarf (WD) candidates in the Sloan Digital Sky Survey (SDSS), including two stars in a common proper motion binary system. These candidates are selected from our 2800deg{sup 2} proper motion survey on the Bok and U.S. Naval Observatory Flagstaff Station 1.3 m telescopes, and they display proper motions of 0.''4-0.''5 yr{sup -1}. Follow-up MMT spectroscopy and near-infrared photometry demonstrate that all three objects are hydrogen-dominated atmosphere WDs with T {sub eff} {approx} 3700-4100 K. For average mass WDs, these temperature estimates correspond to cooling ages of 9-10 Gyr, distances of 70-80 pc, and tangential velocities of 140-200 km s{sup -1}. Based on the UVW space velocities, we conclude that they most likely belong to the halo. Furthermore, the combined main-sequence and WD cooling ages are 10-11 Gyr. Along with SDSS J1102+4113, they are the oldest field WDs currently known. These three stars represent only a small fraction of the halo WD candidates in our proper motion survey, and they demonstrate that deep imaging surveys like the Pan-STARRS and Large Synoptic Survey Telescope should find many old thick disk and halo WDs that can be used to constrain the age of the Galactic thick disk and halo.

Kilic, Mukremin; Brown, Warren R.; McLeod, B. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Munn, Jeffrey A.; Harris, Hugh C. [US Naval Observatory, P.O. Box 1149, Flagstaff, AZ 86002 (United States); Williams, Kurtis A.; DeGennaro, Steven [Department of Astronomy, 1 University Station C1400, Austin, TX 78712 (United States); Kowalski, P. M. [Helmholtz-Centre Potsdam-GFZ German Research Centre for Geosciences, D-14473 Potsdam (Germany); Von Hippel, Ted [Physics Department, Siena College, 515 Loudon Road, Loudonville, NY 12211 (United States); Jeffery, Elizabeth J., E-mail: mkilic@cfa.harvard.ed [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

2010-05-20T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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

Techniques for the measurement of disruption halo currents in the National Spherical Torus Experiment  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

This paper describes techniques for measuring halo currents, and their associated toroidal peaking, in the National Spherical Torus Experiments [M. Ono, et. al, Nuclear Fusion 40, 557 (2000)]. The measurements are based on three techniques: (i) measurement of the toroidal field created by the poloidal halo current, either with segmented Rogowski coils or discrete toroidal field sensors, (ii) the direct measurement of halo currents into specially instrument tiles, and (iii) small Rogowski coils placed on the mechanical supports of in-vessel components. For the segmented Rogowski coils and discrete toroidal field detectors, it is shown that the toroidal peaking factor inferred from the data is significantly less than the peaking factor of the underlying halo current distribution, and a simple model is developed to relate the two. For the array of discrete toroidal field detectors and small Rogowski sensors, the compensation steps that are used to isolate the halo current signal are described. The electrical and mechanical design of compact under-tile resistive shunts and mini-Rogowski coils is described. Example data from the various systems is shown.

Gerhardt, S. P. [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States); Fredrickson, E. [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States); Guttadora, L. [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States); Kaita, R. [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States); Kugel, H. [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States); Menard, J. [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States); Takahashi, H. [Princeton Fusion Research LLC, Princeton, NJ (United States)

2011-10-06T23:59:59.000Z

202

Changes in the halo formation rates due to features in the primordial spectrum  

E-Print Network [OSTI]

Features in the primordial scalar power spectrum provide a possible roadway to describe the outliers at the low multipoles in the WMAP data. Apart from the CMB angular power spectrum, these features can also alter the matter power spectrum and, thereby, the formation of the large scale structure. Carrying out a complete numerical analysis, we investigate the effects of primordial features on the formation rates of the halos. We consider a few different inflationary models that lead to features in the scalar power spectrum and an improved fit to the CMB data, and analyze the corresponding imprints on the formation of halos. Performing a Markov Chain Monte Carlo analysis with the WMAP seven year data and the SDSS halo power spectrum from LRG DR7 for the models of our interest, we arrive at the parameter space of the models allowed by the data. We illustrate that, inflationary potentials, such as the quadratic potential with sinusoidal modulations and the axion monodromy model, which generate certain repeated, oscillatory features in the inflationary perturbation spectrum, do not induce a substantial difference in the number density of halos at their best fit values, when compared with, say, a nearly scale invariant spectrum as is generated by the standard quadratic potential. However, we find that the number density and the formation rates of halos change by about 13-22% for halo masses ranging over 10^4-10^14 solar mass, for potential parameters that lie within 2-sigma around the best fit values arrived at from the aforesaid joint constraints. We briefly discuss the implications of our results.

Dhiraj Kumar Hazra

2013-02-07T23:59:59.000Z

203

Feedback from galactic stellar bulges and hot gaseous haloes of galaxies  

E-Print Network [OSTI]

We demonstrate that the feedback from stellar bulges can play an essential role in shaping the halo gas of galaxies with substantial bulge components by conducting 1-D hydrodynamical simulations. The feedback model we consider consists of two distinct phases: 1) an early starburst during the bulge formation and 2) a subsequent long-lasting mass and energy injection from stellar winds of low-mass stars and Type Ia SNe. An energetic outward blastwave is initiated by the starburst and is maintained and enhanced by the long-lasting stellar feedback. For a MW-like galactic bulge, this blastwave sweeps up the halo gas in the proto-galaxy and heats up the surrounding medium to a scale much beyond the virial radius of the halo, thus the accretion of the halo hot gas can be completely stopped. In addition, the long-lasting feedback in the later phase powers a galactic bulge wind that is reverse-shocked at a large radius in the presence of surrounding intergalactic medium and hence maintains a hot gaseous halo. As the mass and energy injection decreases with time, the feedback evolves to a subsonic and quasi-stable outflow, which is enough to prevent halo gas from cooling. The two phases of the feedback thus re-enforce each-other's impact on the gas dynamics. The simulation results demonstrate that the stellar bulge feedback may provide a plausible solution to the long-standing problems in understanding the MW type galaxies, such as the "missing stellar feedback" problem and the "over-cooling" problem. The simulations also show that the properties of the hot gas in the subsonic outflow state depend sensitively on the environment and the formation history of the bulge. This dependence and variance may explain the large dispersion in the X-ray to B-band luminosity ratio of the low $L_X/L_B$ Es.

Shikui Tang; Q. Daniel Wang; Yu Lu; H. J. Mo

2008-10-30T23:59:59.000Z

204

IAA-AAS-DyCoSS1 -11-03 STATION KEEPING OF A SOLAR SAIL AROUND A HALO ORBIT  

E-Print Network [OSTI]

to deal with the station keeping of a solar sail around a Halo orbit. We first need to understandIAA-AAS-DyCoSS1 -11-03 STATION KEEPING OF A SOLAR SAIL AROUND A HALO ORBIT Ariadna Farr´es and `Angel Jorba Solar sails are a concept of spacecraft propulsion that takes advantage of solar radiation

Barcelona, Universitat de

205

SED, Metallicity and Age of Halo Globular Clusters in M33  

E-Print Network [OSTI]

In this paper we study the properties of ten halo globular clusters in the nearby spiral galaxy M33. CCD images of M33 were obtained as a part of the BATC Colour Survey of the sky in 13 intermediate-band filters from 3800 to 10000{\\AA}. By aperture photometry, we obtain the spectral energy distributions (SEDs) of these globular clusters. We estimate the ages of our sample clusters by comparing the photometry of each object with theoretical stellar population synthesis models for different values of metallicity. Our results suggest that eight of the ten sample halo globular clusters have ``intermediate'' ages, i.e. between 1 and 8 Gyrs.

Ma, J; Chen, J; Wu, H; Jiang, Z; Xue, S; Zhu, J; Ma, Jun; Zhou, Xu; Chen, Jiansheng; Wu, Hong; Jiang, Zhaoji; Xue, Suijian; Zhu, Jin

2002-01-01T23:59:59.000Z

206

Beam Halo Measurements at UMER and the JLAB FEL Using an Adaptive Masking Method  

SciTech Connect (OSTI)

Beam halo is a challenging issue for intense beams since it can cause beam loss, emittance growth, nuclear activation and secondary electron emission. Because of the potentially low number of particles in the halo compared with beam core, traditional imaging methods may not have sufficient contrast to detect faint halos. We have developed a high dynamic range, adaptive masking method to measure halo using a digital micro-mirror array device and demonstrated its effectiveness experimentally on the University of Maryland Electron Ring (UMER). We also report on similar experiments currently in progress at the Jefferson Lab Free Electron Laser (FEL) using this method.

Zhang, H D; Fiorito, R B; Kishek, R A; O& #x27; Shea, P G; Shkvarunets, A G; Benson, S V; Douglas, D; Wilson, F G

2011-03-01T23:59:59.000Z

207

TSC simulation of feedback stabilization of axisymmetric modes in tokamaks using driven halo currents  

SciTech Connect (OSTI)

The Tokamak Simulation Code (TSC) has been used to model a new method of feedback stabilization of the axisymmetric instability in tokamaks using driven halo (or scrapeoff layer) currents. The method appears to be feasible for a wide range of plasma edge parameters. It may offer significant advantages over the more conventional method of controlling this instability when applied in a reactor environment.

Jardin, S.C.; Schmidt, J.A. [Princeton Univ., NJ (United States). Princeton Plasma Physics Lab.

1997-03-01T23:59:59.000Z

208

X-ray Dust Scattering at Small Angles: The Complete Halo around GX13+1  

E-Print Network [OSTI]

The exquisite angular resolution available with Chandra should allow precision measurements of faint diffuse emission surrounding bright sources, such as the X-ray scattering halos created by interstellar dust. However, the ACIS CCDs suffer from pileup when observing bright sources, and this creates difficulties when trying to extract the scattered halo near the source. The initial study of the X-ray halo around GX13+1 using only the ACIS-I detector done by Smith, Edgar & Shafer (2002) suffered from a lack of sensitivity within 50'' of the source, limiting what conclusions could be drawn. To address this problem, observations of GX13+1 were obtained with the Chandra HRC-I and simultaneously with the RXTE PCA. Combined with the existing ACIS-I data, this allowed measurements of the X-ray halo between 2-1000''. After considering a range of dust models, each assumed to be smoothly distributed with or without a dense cloud along the line of sight, the results show that there is no evidence in this data for a dense cloud near the source, as suggested by Xiang et al. (2005). Finally, although no model leads to formally acceptable results, the Weingartner & Draine (2001) and nearly all of the composite grain models from Zubko, Dwek & Arendt (2004) give poor fits.

Randall K. Smith

2008-05-04T23:59:59.000Z

209

Cosmic Ray Acceleration beyond the Knee up to the Ankle in the Galactic Wind Halo  

E-Print Network [OSTI]

Cosmic Ray Acceleration beyond the Knee up to the Ankle in the Galactic Wind Halo Vladimir the so-called knee at several #2;10 15 eV to the so-called ankle at a few #2;10 18 eV total energy

210

The Structure and Dark Halo Core Properties of Dwarf Spheroidal Galaxies  

E-Print Network [OSTI]

The structure and dark matter halo core properties of dwarf spheroidal galaxies (dSphs) are investigated. A double-isothermal model of an isothermal stellar system, embedded in an isothermal dark halo core provides an excellent fit to the various observed stellar surface density distributions. The stellar system can be well characterised by King profiles with a broad distribution of concentration parameters c. The core scale length of the stellar system a_* is sensitive to the central dark matter density rho_0. In contrast to single-component systems, the cut-off radius of the stellar system, rs_t, however does not trace the tidal radius but the core radius r_c of its dark matter halo. c is therefore sensitive to the ratio of the stellar to the dark matter velocity dispersion, sigma_*/sigma_0. Simple empirical relationships are derived that allow to calculate the dark halo core parameters rho_0, r_c and sigma_0, given the observable quantities sigma_*, a_* and c. The DIS model is applied to the Milky Way's dS...

Burkert, Andreas

2015-01-01T23:59:59.000Z

211

Rare measurements of a sprite with halo event driven by a negative lightning discharge over Argentina  

E-Print Network [OSTI]

Argentina M. J. Taylor,1 M. A. Bailey,1 P. D. Pautet,1 S. A. Cummer,2 N. Jaugey,2 J. N. Thomas,3,4 N. N measurements were made of a mesoscale thunderstorm observed on February 22­23, 2006 over northern Argentina of a sprite with halo event driven by a negative lightning discharge over Argentina, Geophys. Res. Lett., 35

Thomas, Jeremy N.

212

MHD wave refraction and the acoustic halo effect around solar active regions - a 3D study  

E-Print Network [OSTI]

An enhancement in high-frequency acoustic power is commonly observed in the solar photosphere and chromosphere surrounding magnetic active regions. We perform 3D linear forward wave modelling with a simple wavelet pulse acoustic source to ascertain whether the formation of the acoustic halo is caused by MHD mode conversion through regions of moderate and inclined magnetic fields. This conversion type is most efficient when high frequency waves from below intersect magnetic field lines at a large angle. We find a strong relationship between halo formation and the equipartition surface at which the Alfv\\'en speed $a$ matches the sound speed $c$, lending support to the theory that photospheric and chromospheric halo enhancement is due to the creation and subsequent reflection of magnetically dominated fast waves from essentially acoustic waves as they cross $a=c$. In simulations where we have capped $a$ such that waves are not permitted to refract after reaching the $a=c$ height, halos are non-existent, which su...

Rijs, Carlos; Przybylski, Damien; Cally, Paul S

2015-01-01T23:59:59.000Z

213

Application of Diamond and Sapphire Sensors in the Beam Halo Monitor for FLASH  

E-Print Network [OSTI]

, ionization chambers, a beam halo monitor (BHM) and beam position monitors (BPM) has been installed. The BHM, a BHM system and a magnetic BPM (also called "in-air" BPM) [8] operating in conjunction in order not hit the beam pipe downstream from the exit window. The BPM detects the center of gravity of the beam

214

Photometry and the Metallicity Distribution of the Outer Halo of M31  

E-Print Network [OSTI]

We have conducted a wide-field CCD-mosaic study of the resolved red-giant branch (RGB) stars of M31, in a field located 20 kpc from the nucleus along the SE minor axis. In our (I, V-I) color-magnitude diagram, RGB stars in the top three magnitudes of the M31 halo are strongly present. Photometry of a more distant control field to subtract field contamination is used to derive the `cleaned' luminosity function and metallicity distribution function (MDF) of the M31 halo field. From the color distribution of the foreground Milky Way halo stars, we find a reddening E(V-I)= 0.10 +/- 0.02 for this field, and from the luminosity of the RGB tip, we determine a distance modulus (m-M)_o = 24.47 +/- 0.12 (= 783 +/- 43 kpc). The MDF is derived from interpolation within an extensive new grid of RGB models (Vandenberg et al. 2000). The MDF is dominated by a moderately high-metallicity population ([m/H]~ -0.5) found previously in more interior M31 halo/bulge fields, and is much more metal-rich than the [m/H]~ -1.5 level in the Milky Way halo. A significant (~30% - 40%, depending on AGB star contribution) metal-poor population is also present. To first order, the shape of the MDF resembles that predicted by a simple, single-component model of chemical evolution starting from primordial gas with an effective yield y=0.0055. It strongly resembles the MDF recently found for the outer halo of the giant elliptical NGC 5128 (Harris et al. 2000), though NGC 5128 has an even lower fraction of low-metallicity stars. Intriguingly, in both NGC 5128 and M31, the metallicity distribution of the globular clusters in M31 does not match the halo stars; the clusters are far more heavily weighted to metal-poor objects. We suggest similarities in the formation and early evolution of massive, spheroidal stellar systems.

Patrick R. Durrell; William E. Harris; Christopher J. Pritchet

2001-01-24T23:59:59.000Z

215

THE STELLAR METALLICITY DISTRIBUTION FUNCTION OF THE GALACTIC HALO FROM SDSS PHOTOMETRY  

SciTech Connect (OSTI)

We explore the stellar metallicity distribution function of the Galactic halo based on SDSS ugriz photometry. A set of stellar isochrones is calibrated using observations of several star clusters and validated by comparisons with medium-resolution spectroscopic values over a wide range of metal abundance. We estimate distances and metallicities for individual main-sequence stars in the multiply scanned SDSS Stripe 82, at heliocentric distances in the range 5-8 kpc and |b| > 35 Degree-Sign , and find that the in situ photometric metallicity distribution has a shape that matches that of the kinematically selected local halo stars from Ryan and Norris. We also examine independent kinematic information from proper-motion measurements for high Galactic latitude stars in our sample. We find that stars with retrograde rotation in the rest frame of the Galaxy are generally more metal poor than those exhibiting prograde rotation, which is consistent with earlier arguments by Carollo et al. that the halo system comprises at least two spatially overlapping components with differing metallicity, kinematics, and spatial distributions. The observed photometric metallicity distribution and that of Ryan and Norris can be described by a simple chemical evolution model by Hartwick (or by a single Gaussian distribution); however, the suggestive metallicity-kinematic correlation contradicts the basic assumption in this model that the Milky Way halo consists primarily of a single stellar population. When the observed metallicity distribution is deconvolved using two Gaussian components with peaks at [Fe/H] Almost-Equal-To -1.7 and -2.3, the metal-poor component accounts for {approx}20%-35% of the entire halo population in this distance range.

An, Deokkeun [Department of Science Education, Ewha Womans University, Seoul 120-750 (Korea, Republic of)] [Department of Science Education, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Beers, Timothy C. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States)] [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Johnson, Jennifer A.; Pinsonneault, Marc H. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)] [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Lee, Young Sun [Department of Physics and Astronomy and JINA (Joint Institute for Nuclear Astrophysics), Michigan State University, E. Lansing, MI 48824 (United States)] [Department of Physics and Astronomy and JINA (Joint Institute for Nuclear Astrophysics), Michigan State University, E. Lansing, MI 48824 (United States); Bovy, Jo [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)] [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States); Ivezic, Zeljko [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States)] [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Carollo, Daniela [Macquarie University Research Centre in Astronomy, Astrophysics and Astrophotonics, Department of Physics and Astronomy, Macquarie University, NSW 2109 (Australia)] [Macquarie University Research Centre in Astronomy, Astrophysics and Astrophotonics, Department of Physics and Astronomy, Macquarie University, NSW 2109 (Australia); Newby, Matthew, E-mail: deokkeun@ewha.ac.kr [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute Troy, NY 12180 (United States)] [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute Troy, NY 12180 (United States)

2013-01-20T23:59:59.000Z

216

Accurate universal models for the mass accretion histories and concentrations of dark matter halos  

E-Print Network [OSTI]

A large amount of observations have constrained cosmological parameters and the initial density fluctuation spectrum to a very high accuracy. However, cosmological parameters change with time and the power index of the power spectrum varies with mass scale dramatically in the so-called concordance Lambda CDM cosmology. Thus, any successful model for its structural evolution should work well simultaneously for various cosmological models and different power spectra. We use a large set of high-resolution N-body simulations of a variety of structure formation models (scale-free, standard CDM, open CDM, and Lambda CDM) to study the mass accretion histories (MAHs), the mass and redshift dependence of concentrations and the concentration evolution histories of dark matter halos. We find that there is significant disagreement between the much-used empirical models in the literature and our simulations. According to two simple but tight correlations we find from the simulation results, we develop new empirical models for both the MAHs and the concentration evolution histories of dark matter halos, and the latter can also be used to predict the mass and redshift dependence of halo concentrations. These models are accurate and universal: the same set of model parameters works well for different cosmological models and for halos of different masses at different redshifts and the model predictions are highly accurate even when the histories are traced to very high redshift. These models are also simple and easy to implement. A web calculator and a user-friendly code to make the relevant calculations are available from http://www.shao.ac.cn/dhzhao/mandc.html . We explain why Lambda CDM halos on nearly all mass scales show two distinct phases in their evolution histories.

D. H. Zhao; Y. P. Jing; H. J. Mo; G. Boerner

2009-11-30T23:59:59.000Z

217

Non-power law behavior of the radial profile of phase-space density of halos  

SciTech Connect (OSTI)

We study the pseudo phase-space density, ?(r)/?{sup 3}(r), of ?CDM dark matter halos with and without baryons (baryons+DM, and pure DM), by using the model introduced in Del Popolo (2009), which takes into account the effect of dynamical friction, ordered and random angular momentum, baryons adiabatic contraction and dark matter baryons interplay. We examine the radial dependence of ?(r)/?{sup 3}(r) over 9 orders of magnitude in radius for structures on galactic and cluster of galaxies scales. We find that ?(r)/?{sup 3}(r) is approximately a power-law only in the range of halo radius resolved by current simulations (down to 0.1% of the virial radius) while it has a non-power law behavior below the quoted scale, with inner profiles changing with mass. The non-power-law behavior is more evident for halos constituted both of dark matter and baryons while halos constituted just of dark matter and with angular momentum chosen to reproduce a Navarro-Frenk-White (NFW) density profile, are characterized by an approximately power-law behavior. The results of the present paper lead to conclude that density profiles of the NFW type are compatible with a power-law behavior of ?(r)/?{sup 3}(r), while those flattening to the halo center, like those found in Del Popolo (2009) or the Einasto profile, or the Burkert profile, cannot produce radial profile of the pseudo-phase-space density that are power-laws at all radii. The results argue against universality of the pseudo phase-space density and as a consequence argue against universality of density profiles constituted by dark matter and baryons as also discussed in Del Popolo (2009)

Popolo, A. Del, E-mail: adelpopolo@oact.inaf.it [Dipartimento di Fisica e Astronomia, University Of Catania, Viale Andrea Doria 6, 95125 Catania (Italy)

2011-07-01T23:59:59.000Z

218

RHAPSODY. I. STRUCTURAL PROPERTIES AND FORMATION HISTORY FROM A STATISTICAL SAMPLE OF RE-SIMULATED CLUSTER-SIZE HALOS  

SciTech Connect (OSTI)

We present the first results from the RHAPSODY cluster re-simulation project: a sample of 96 'zoom-in' simulations of dark matter halos of 10{sup 14.8{+-}0.05} h {sup -1} M {sub Sun }, selected from a 1 h {sup -3} Gpc{sup 3} volume. This simulation suite is the first to resolve this many halos with {approx}5 Multiplication-Sign 10{sup 6} particles per halo in the cluster mass regime, allowing us to statistically characterize the distribution of and correlation between halo properties at fixed mass. We focus on the properties of the main halos and how they are affected by formation history, which we track back to z = 12, over five decades in mass. We give particular attention to the impact of the formation history on the density profiles of the halos. We find that the deviations from the Navarro-Frenk-White (NFW) model and the Einasto model depend on formation time. Late-forming halos tend to have considerable deviations from both models, partly due to the presence of massive subhalos, while early-forming halos deviate less but still significantly from the NFW model and are better described by the Einasto model. We find that the halo shapes depend only moderately on formation time. Departure from spherical symmetry impacts the density profiles through the anisotropic distribution of massive subhalos. Further evidence of the impact of subhalos is provided by analyzing the phase-space structure. A detailed analysis of the properties of the subhalo population in RHAPSODY is presented in a companion paper.

Wu, Hao-Yi; Hahn, Oliver; Wechsler, Risa H.; Mao, Yao-Yuan; Behroozi, Peter S., E-mail: hywu@umich.edu [Kavli Institute for Particle Astrophysics and Cosmology, Physics Department, Stanford University, Stanford, CA 94305 (United States)

2013-02-15T23:59:59.000Z

219

USING THE X-RAY DUST SCATTERING HALO OF CYGNUS X-1 TO DETERMINE DISTANCE AND DUST DISTRIBUTIONS  

E-Print Network [OSTI]

We present a detailed study of the X-ray dust scattering halo of the black hole candidate Cygnus X-1 based on two Chandra High Energy Transmission Gratings Spectrometer observations. Using 18 different dust models, including ...

Xiang, Jingen

220

Quantifying the Cosmic Web I: The large-scale halo ellipticity-ellipticity and ellipticity-direction correlations  

E-Print Network [OSTI]

The formation of dark matter halos tends to occur anisotropically along the filaments of the Cosmic Web, which induces both ellipticity-ellipticity (EE) correlations between the shapes of halos, as well as ellipticity-direction (ED) cross-correlations between halo shapes and the directions to neighboring halos. We analyze the halo catalogue and the semi-analytic galaxy catalogue of the recent Millennium Run Simulation to measure the EE and ED correlations numerically at four different redshifts (z=0, 0.5, 1 and 2). For the EE correlations, we find that (i) the major-axis correlation is strongest while the intermediate-axis correlation is weakest; (ii) the signal is significant at distances out to 10 Mpc/h; (iii) the signal decreases as z decreases; (iv) and its behavior depends strongly on the halo mass scale, with larger masses showing stronger correlations at large distances. For the ED correlations, we find that (i) the correlations are much stronger than the EE correlations, and are significant even out to distances of 50 Mpc/h; (ii) the signal also decreases as z decreases; (iii) and it increases with halo mass at all distances. We also provide empirical fitting functions for the EE and ED correlations. The EE correlations are found to scale linearly with the linear density correlation function, xi(r). While the ED cross-correlation is found to scale as xi^{1/2}(r) at large distances beyond 10 Mpc/h. The best-fit values of the fitting parameters for the EE and the ED correlations are all determined through chi^{2}-statistics. Our results may be useful for quantifying the filamentary distribution of dark matter halos over a wide range of scales.

Jounghun Lee; Volker Springel; Ue-Li Pen; Gerard Lemson

2008-06-20T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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.


221

The modified dynamics (MOND) predicts an absolute maximum to the acceleration produced by `dark halos'  

E-Print Network [OSTI]

We have recently discovered that the modified dynamics (MOND) implies some universal upper bound on the acceleration that can be contributed by a `dark halo'--assumed in a Newtonian analysis to account for the effects of MOND. Not surprisingly, the limit is of the order of the acceleration constant of the theory. This can be contrasted directly with the results of structure-formation simulations. The new limit is substantial and different from earlier MOND acceleration limits (discussed in connection with the MOND explanation of the Freeman law for galaxy disks, and the Fish law for ellipticals): It pertains to the `halo', and not to the observed galaxy; it is absolute, and independent of further physical assumptions on the nature of the galactic system; and it applies at all radii, whereas the other limits apply only to the mean acceleration in the system.

Rafael Brada; Mordehai Milgrom

1998-12-21T23:59:59.000Z

222

HOT GAS HALOS AROUND DISK GALAXIES: CONFRONTING COSMOLOGICAL SIMULATIONS WITH OBSERVATIONS  

SciTech Connect (OSTI)

Models of disk galaxy formation commonly predict the existence of an extended reservoir of accreted hot gas surrounding massive spirals at low redshift. As a test of these models, we use X-ray and H{alpha} data of the two massive, quiescent edge-on spirals NGC 5746 and NGC 5170 to investigate the amount and origin of any hot gas in their halos. Contrary to our earlier claim, the Chandra analysis of NGC 5746, employing more recent calibration data, does not reveal any significant evidence for diffuse X-ray emission outside the optical disk, with a 3{sigma} upper limit to the halo X-ray luminosity of 4 x 10{sup 39} erg s{sup -1}. An identical study of the less massive NGC 5170 also fails to detect any extraplanar X-ray emission. By extracting hot halo properties of disk galaxies formed in cosmological hydrodynamical simulations, we compare these results to expectations for cosmological accretion of hot gas by spirals. For Milky-Way-sized galaxies, these high-resolution simulations predict hot halo X-ray luminosities which are lower by a factor of {approx}2 compared to our earlier results reported by Toft et al. We find the new simulation predictions to be consistent with our observational constraints for both NGC 5746 and NGC 5170, while also confirming that the hot gas detected so far around more actively star-forming spirals is in general probably associated with stellar activity in the disk. Observational results on quiescent disk galaxies at the high-mass end are nevertheless providing powerful constraints on theoretical predictions, and hence on the assumed input physics in numerical studies of disk galaxy formation and evolution.

Rasmussen, Jesper [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Sommer-Larsen, Jesper [Excellence Cluster Universe, Technische Universitaet Muenchen, Boltzmannstr. 2, D-85748 Garching bei Muenchen (Germany); Pedersen, Kristian; Toft, Sune; Grove, Lisbeth F. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Benson, Andrew [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Mail Code 130-33, Pasadena, CA 91125 (United States); Bower, Richard G. [Institute for Computational Cosmology, University of Durham, South Road, Durham DH1 3LE (United Kingdom)], E-mail: jr@ociw.edu

2009-05-20T23:59:59.000Z

223

The Relationship Between Baryons and Dark Matter in Extended Galaxy Halos  

E-Print Network [OSTI]

The relationship between gas-rich galaxies and Ly-alpha absorbers is addressed in this paper in the context of the baryonic content of galaxy halos. Deep Arecibo HI observations are presented of two gas-rich spiral galaxies within 125 kpc projected distance of a Ly-alpha absorber at a similar velocity. The galaxies investigated are close to edge-on and the absorbers lie almost along their major axes, allowing for a comparison of the Ly-alpha absorber velocities with galactic rotation. This comparison is used to examine whether the absorbers are diffuse gas rotating with the galaxies' halos, outflow material from the galaxies, or intergalactic gas in the low redshift cosmic web. The results indicate that if the gas resides in the galaxies' halos it is not rotating with the system and possibly counter-rotating. In addition, simple geometry indicates the gas was not ejected from the galaxies and there are no gas-rich satellites detected down to 3.6 - 7.5 x 10^6 Msun, or remnants of satellites to 5-6 x 10^{18} cm^{-2}. The gas could potentially be infalling from large radii, but the velocities and distances are rather high compared to the high velocity clouds around the Milky Way. The most likely explanation is the galaxies and absorbers are not directly associated, despite the vicinity of the spiral galaxies to the absorbers (58-77 kpc from the HI edge). The spiral galaxies reside in a filament of intergalactic gas, and the gas detected by the absorber has not yet come into equilibrium with the galaxy. These results also indicate that the massive, extended dark matter halos of spiral galaxies do not commonly have an associated diffuse baryonic component at large radii.

M. E. Putman; J. L. Rosenberg; J. T. Stocke; R. McEntaffer

2005-10-11T23:59:59.000Z

224

The outer regions of the giant Virgo galaxy M87 II. Kinematic separation of stellar halo and intracluster light  

E-Print Network [OSTI]

We present a spectroscopic study of 287 Planetary Nebulas (PNs) in a total area of ~0.4 deg^2 around the BCG M87 in Virgo A. With these data we can distinguish the stellar halo from the co-spatial intracluster light (ICL). PNs were identified from their narrow and symmetric redshifted lambda 5007\\4959 Angstrom [OIII] emission lines, and the absence of significant continuum. We implement a robust technique to measure the halo velocity dispersion from the projected phase-space to identify PNs associated with the M87 halo and ICL. The velocity distribution of the spectroscopically confirmed PNs is bimodal, containing a narrow component centred on the systemic velocity of the BCG and an off-centred broader component, that we identify as halo and ICL, respectively. Halo and ICPN have different spatial distributions: the halo PNs follow the galaxy's light, whereas the ICPNs are characterised by a shallower power-law profile. The composite PN number density profile shows the superposition of different PN populations...

Longobardi, Alessia; Gerhard, Ortwin; Hanuschik, Reinhard

2015-01-01T23:59:59.000Z

225

Fusion and Direct Reactions of Halo Nuclei at Energies around the Coulomb Barrier  

E-Print Network [OSTI]

The present understanding of reaction processes involving light unstable nuclei at energies around the Coulomb barrier is reviewed. The effect of coupling to direct reaction channels on elastic scattering and fusion is investigated, with the focus on halo nuclei. A list of definitions of processes is given, followed by a review of the experimental and theoretical tools and information presently available. The effect of couplings on elastic scattering and fusion is studied with a series of model calculations within the coupled-channels framework. The experimental data on fusion are compared to "bare" no-coupling one-dimensional barrier penetration model calculations. On the basis of these calculations and comparisons with experimental data, conclusions are drawn from the observation of recurring features. The total fusion cross sections for halo nuclei show a suppression with respect to the "bare" calculations at energies just above the barrier that is probably due to single neutron transfer reactions. The data for total fusion are also consistent with a possible sub-barrier enhancement; however, this observation is not conclusive and other couplings besides the single-neutron channels would be needed in order to explain any actual enhancement. We find that a characteristic feature of halo nuclei is the dominance of direct reactions over fusion at near and sub-barrier energies; the main part of the cross section is related to neutron transfers, while calculations indicate only a modest contribution from the breakup process.

N. Keeley; R. Raabe; N. Alamanos; J. L. Sida

2007-02-16T23:59:59.000Z

226

Changes in the halo formation rates due to features in the primordial spectrum  

E-Print Network [OSTI]

Features in the primordial scalar power spectrum provide a possible roadway to describe the outliers at the low multipoles in the WMAP data. Apart from the CMB angular power spectrum, these features can also alter the matter power spectrum and, thereby, the formation of the large scale structure. Carrying out a complete numerical analysis, we investigate the effects of primordial features on the formation rates of the halos. We consider a few different inflationary models that lead to features in the scalar power spectrum and an improved fit to the CMB data, and analyze the corresponding imprints on the formation of halos. Performing a Markov Chain Monte Carlo analysis with the WMAP seven year data and the SDSS halo power spectrum from LRG DR7 for the models of our interest, we arrive at the parameter space of the models allowed by the data. We illustrate that, inflationary potentials, such as the quadratic potential with sinusoidal modulations and the axion monodromy model, which generate certain repeated, o...

Hazra, Dhiraj Kumar

2012-01-01T23:59:59.000Z

227

Ongoing Galactic Accretion: Simulations and Observations of Condensed Gas in Hot Halos  

E-Print Network [OSTI]

Ongoing accretion onto galactic disks has been recently theorized to progress via the unstable cooling of the baryonic halo into condensed clouds. These clouds have been identified as analogous to the High-Velocity Clouds (HVCs) observed in HI in our Galaxy. Here we compare the distribution of HVCs observed around our own Galaxy and extra-planar gas around the Andromeda galaxy to these possible HVC analogs in a simulation of galaxy formation that naturally generates these condensed clouds. We find a very good correspondence between these observations and the simulation, in terms of number, angular size, velocity distribution, overall flux and flux distribution of the clouds. We show that condensed cloud accretion only accounts for ~ 0.2 M_solar / year of the current overall Galactic accretion in the simulations. We also find that the simulated halo clouds accelerate and become more massive as they fall toward the disk. The parameter space of the simulated clouds is consistent with all of the observed HVC complexes that have distance constraints, except the Magellanic Stream which is known to have a different origin. We also find that nearly half of these simulated halo clouds would be indistinguishable from lower-velocity gas and that this effect is strongest further from the disk of the galaxy, thus indicating a possible missing population of HVCs. These results indicate that the majority of HVCs are consistent with being infalling, condensed clouds that are a remnant of Galaxy formation.

J. E. G. Peek; M. E. Putman; Jesper Sommer-Larsen

2007-09-11T23:59:59.000Z

228

Tracing the Metal-Poor M31 Stellar Halo with Blue Horizontal Branch Stars  

E-Print Network [OSTI]

We have analyzed new HST/ACS and HST/WFC3 imaging in F475W and F814W of two previously-unobserved fields along the M31 minor axis to confirm our previous constraints on the shape of M31's inner stellar halo. Both of these new datasets reach a depth of at least F814W$blue horizontal branch (BHB) of the field as a distinct feature of the color-magnitude diagram. We measure the density of BHB stars and the ratio of BHB to red giant branch stars in each field using identical techniques to our previous work. We find excellent agreement with our previous measurement of a power-law for the 2-D projected surface density with an index of 2.6$^{+0.3}_{-0.2}$ outside of 3 kpc, which flattens to $\\alpha <$1.2 inside of 3 kpc. Our findings confirm our previous suggestion that the field BHB stars in M31 are part of the halo population. However, the total halo profile is now known to differ from this BHB profile, which suggests that we have isolated the metal-poor component. This component ...

Williams, Benjamin F; Gilbert, Eric F BellKaroline M; Guhathakurta, Puragra; Dorman, Claire; Lauer, Tod R; Seth, Anil C; Kalirai, Jason S; Rosenfield, Philip; Girardi, Leo

2015-01-01T23:59:59.000Z

229

NIHAO project II: Halo shape, phase-space density and velocity distribution of dark matter in galaxy formation simulations  

E-Print Network [OSTI]

We show the effect of galaxy formation on the dark matter (DM) distribution across a wide range of halo masses. We focus on how baryon physics changes the dark matter halo shape, the so called "pseudo phase-space density distribution" and the velocity distribution within the virial radius, Rvir and in the solar neighborhood. This study is based on the NIHAO galaxy formation simulations, a large suite of cosmological zoom-in simulations. The galaxies reproduce key properties of observed galaxies, and hence offer unique insight into how baryons change the dark matter morphology and kinematics. When compared to dark matter only simulations, the NIHAO haloes have similar shapes at Rvir, but are substantially rounder inside ~0.1 Rvir. In DM-only simulations the inner halo has a minor-to-major axis ratio of c/a~0.5. In hydro simulations c/a increases with halo mass and integrated star formation efficiency, reaching ~0.8 at the Milky Way mass, reconciling a long-standing conflict between observations and DM only sim...

Butsky, Iryna; Dutton, Aaron A; Wang, Liang; Stinson, Greg S; Penzo, Camilla; Kang, Xi; Keller, Ben W; Wadsley, James

2015-01-01T23:59:59.000Z

230

DEEP 1.4 GHz FOLLOW-UP OF THE STEEP SPECTRUM RADIO HALO IN A521  

SciTech Connect (OSTI)

In a recent paper, we reported on the discovery of a radio halo with very steep spectrum in the merging galaxy cluster A521 through observations with the Giant Metrewave Radio Telescope. We showed that the steep spectrum of the halo is inconsistent with a secondary origin of the relativistic electrons and supports a turbulent acceleration scenario. At that time, due to the steep spectrum, the available observations at 1.4 GHz (archival NRAO-Very Large Array-VLA-CnB-configuration data) were not adequate to accurately determine the flux density associated with the radio halo. In this paper, we report the detection at 1.4 GHz of the radio halo in A521 using deep VLA observations in the D configuration. We use these new data to confirm the steep spectrum of the object. We consider A521 the prototype of a population of very steep spectrum halos. This population is predicted assuming that turbulence plays an important role in the acceleration of relativistic particles in galaxy clusters, and we expect it will be unveiled by future surveys at low frequencies with the LOFAR and LWA radio telescopes.

Dallacasa, D.; Macario, G.; Setti, G. [Dipartimento di Astronomia, Universita di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Brunetti, G.; Cassano, R.; Venturi, T. [INAF-Istituto di Radioastronomia, via Gobetti 101, I-40129 Bologna (Italy); Giacintucci, S. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Kassim, N. E.; Lane, W. [Naval Research Laboratory, Code 7213, Washington, DC 20375-5320 (United States)

2009-07-10T23:59:59.000Z

231

DISCOVERY OF A GIANT RADIO HALO IN A NEW PLANCK GALAXY CLUSTER PLCKG171.9-40.7  

SciTech Connect (OSTI)

We report the discovery of a giant radio halo in a new, hot, X-ray luminous galaxy cluster recently found by Planck, PLCKG171.9-40.7. The radio halo was found using Giant Metrewave Radio Telescope observations at 235 MHz and 610 MHz, and in the 1.4 GHz data from an NRAO Very Large Array Sky Survey pointing that we have reanalyzed. The diffuse radio emission is coincident with the cluster X-ray emission, and has an extent of {approx}1 Mpc and a radio power of {approx}5 Multiplication-Sign 10{sup 24} W Hz{sup -1} at 1.4 GHz. Its integrated radio spectrum has a slope of {alpha} Almost-Equal-To 1.8 between 235 MHz and 1.4 GHz, steeper than that of a typical giant halo. The analysis of the archival XMM-Newton X-ray data shows that the cluster is hot ({approx}10 keV) and disturbed, consistent with X-ray-selected clusters hosting radio halos. This is the first giant radio halo discovered in one of the new clusters found by Planck.

Giacintucci, Simona [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)] [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Kale, Ruta; Venturi, Tiziana [INAF-Istituto di Radioastronomia, via Gobetti 101, I-40129 Bologna (Italy)] [INAF-Istituto di Radioastronomia, via Gobetti 101, I-40129 Bologna (Italy); Wik, Daniel R.; Markevitch, Maxim, E-mail: simona@astro.umd.edu [Astrophysics Science Division, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States)] [Astrophysics Science Division, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2013-03-20T23:59:59.000Z

232

THE COS-HALOS SURVEY: RATIONALE, DESIGN, AND A CENSUS OF CIRCUMGALACTIC NEUTRAL HYDROGEN  

SciTech Connect (OSTI)

We present the design and methods of the COS-Halos survey, a systematic investigation of the gaseous halos of 44 z = 0.15-0.35 galaxies using background QSOs observed with the Cosmic Origins Spectrograph aboard the Hubble Space Telescope. This survey has yielded 39 spectra of z{sub em} ? 0.5 QSOs with S/N ?10-15 per resolution element. The QSO sightlines pass within 150 physical kpc of the galaxies, which span early and late types over stellar mass log M{sub *}/M{sub ?} = 9.5-11.5. We find that the circumgalactic medium exhibits strong H I, averaging ? 1 in Ly? equivalent width out to 150 kpc, with 100% covering fraction for star-forming galaxies and 75% covering for passive galaxies. We find good agreement in column densities between this survey and previous studies over similar range of impact parameter. There is weak evidence for a difference between early- and late-type galaxies in the strength and distribution of H I. Kinematics indicate that the detected material is bound to the host galaxy, such that ?> 90% of the detected column density is confined within 200 km s{sup 1} of the galaxies. This material generally exists well below the halo virial temperatures at T ?< 10{sup 5} K. We evaluate a number of possible origin scenarios for the detected material, and in the end favor a simple model in which the bulk of the detected H I arises in a bound, cool, low-density photoionized diffuse medium that is generic to all L* galaxies and may harbor a total gaseous mass comparable to galactic stellar masses.

Tumlinson, Jason; Thom, Christopher; Sembach, Kenneth R. [Space Telescope Science Institute, Baltimore, MD (United States); Werk, Jessica K.; Prochaska, J. Xavier [UCO/Lick Observatory, University of California, Santa Cruz, CA (United States); Tripp, Todd M.; Katz, Neal; Meiring, Joseph D. [Department of Astronomy, University of Massachusetts, Amherst, MA (United States); Dav, Romeel [University of the Western Cape, South African Astronomical Observatories, and African Institute for Mathematical Sciences, Cape Town (South Africa); Oppenheimer, Benjamin D. [Leiden Observatory, Leiden University, 2300 RA Leiden (Netherlands); Ford, Amanda Brady [Steward Observatory, University of Arizona, Tucson, AZ (United States); O'Meara, John M. [Department of Chemistry and Physics, Saint Michael's College, Colchester, VT (United States); Peeples, Molly S. [Center for Galaxy Evolution, University of California Los Angeles, Los Angeles, CA (United States); Weinberg, David H. [Department of Astronomy, The Ohio State University, Columbus, OH (United States)

2013-11-01T23:59:59.000Z

233

The dark matter halos of massive, relaxed galaxy clusters observed with Chandra  

E-Print Network [OSTI]

We use the Chandra X-ray Observatory to study the dark matter halos of 34 massive, dynamically relaxed galaxy clusters, spanning the redshift range 0.06halos; for ~80 per cent of the clusters, the NFW model provides a statistically acceptable fit. In contrast, the singular isothermal sphere model can, in almost every case, be completely ruled out. We observe a well-defined mass-concentration relation for the clusters with an intrinsic scatter in good agreement with the predictions from simulations. The slope of the mass-concentration relation, c\\propto M_vir^a/(1+z)^b with a=-0.45\\pm0.12 at 95 per cent confidence, is steeper than the value a~-0.1 predicted by CDM simulations for lower mass halos. With the slope a included as a free fit parameter, the redshift evolution of the concentration parameter, b=0.71\\pm0.52 at 95 per cent confidence, is consistent with the same simulations (b~1). Fixing a~-0.1 leads to an apparent evolution that is significantly slower, b=0.30\\pm0.49, although the goodness of fit in this case is significantly worse. Using a generalized NFW model, we find the inner dark matter density slope, alpha, to be consistent with unity at 95 per cent confidence for the majority of clusters. Combining the results for all clusters for which the generalized NFW model provides a good description of the data, we measure alpha=0.88\\pm0.29 at 95 per cent confidence, in agreement with CDM model predictions.

R. W. Schmidt; S. W. Allen

2007-05-09T23:59:59.000Z

234

A MEGACAM SURVEY OF OUTER HALO SATELLITES. II. BLUE STRAGGLERS IN THE LOWEST STELLAR DENSITY SYSTEMS  

SciTech Connect (OSTI)

We present a homogeneous study of blue straggler stars across 10 outer halo globular clusters, 3 classical dwarf spheroidal galaxies, and 9 ultra-faint galaxies based on deep and wide-field photometric data taken with MegaCam on the Canada-France-Hawaii Telescope. We find blue straggler stars to be ubiquitous among these Milky Way satellites. Based on these data, we can test the importance of primordial binaries or multiple systems on blue straggler star formation in low-density environments. For the outer halo globular clusters, we find an anti-correlation between the specific frequency of blue stragglers and absolute magnitude, similar to that previously observed for inner halo clusters. When plotted against density and encounter rate, the frequency of blue stragglers is well fit by a single trend with a smooth transition between dwarf galaxies and globular clusters; this result points to a common origin for these satellites' blue stragglers. The fraction of blue stragglers stays constant and high in the low encounter rate regime spanned by our dwarf galaxies, and decreases with density and encounter rate in the range spanned by our globular clusters. We find that young stars can mimic blue stragglers in dwarf galaxies only if their ages are 2.5 {+-} 0.5 Gyr and they represent {approx}1%-7% of the total number of stars, which we deem highly unlikely. These results point to mass-transfer or mergers of primordial binaries or multiple systems as the dominant blue straggler formation mechanism in low-density systems.

Santana, Felipe A.; Munoz, Ricardo R. [Departamento de Astronomia, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago (Chile); Geha, Marla [Astronomy Department, Yale University, New Haven, CT 06520 (United States); Cote, Patrick; Stetson, Peter [Herzberg Institute of Astrophysics, National Research Council of Canada, Victoria, BC, V9E 2E7 (Canada); Simon, Joshua D. [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Djorgovski, S. G., E-mail: fsantana@das.uchile.cl, E-mail: rmunoz@das.uchile.cl [Astronomy Department, California Institute of Technology, Pasadena, CA, 91125 (United States)

2013-09-10T23:59:59.000Z

235

Predicting Galaxy Star Formation Rates via the Co-evolution of Galaxies and Halos  

SciTech Connect (OSTI)

In this paper, we test the age matching hypothesis that the star formation rate (SFR) of a galaxy is determined by its dark matter halo formation history, and as such, that more quiescent galaxies reside in older halos. This simple model has been remarkably successful at predicting color-based galaxy statistics at low redshift as measured in the Sloan Digital Sky Survey (SDSS). To further test this method with observations, we present new SDSS measurements of the galaxy two-point correlation function and galaxy-galaxy lensing as a function of stellar mass and SFR, separated into quenched and star forming galaxy samples. We find that our age matching model is in excellent agreement with these new measurements. We also employ a galaxy group finder and show that our model is able to predict: (1) the relative SFRs of central and satellite galaxies, (2) the SFR-dependence of the radial distribution of satellite galaxy populations within galaxy groups, rich groups, and clusters and their surrounding larger scale environments, and (3) the interesting feature that the satellite quenched fraction as a function of projected radial distance from the central galaxy exhibits an approx r-.15 slope, independent of environment. The accurate prediction for the spatial distribution of satellites is intriguing given the fact that we do not explicitly model satellite-specific processes after infall, and that in our model the virial radius does not mark a special transition region in the evolution of a satellite, contrary to most galaxy evolution models. The success of the model suggests that present-day galaxy SFR is strongly correlated with halo mass assembly history.

Watson, Douglas F.; Hearin, Andrew P.; Berlind, Andreas A.; Becker, Matthew R.; Behroozi, Peter S.; Skibba, Ramin A.; Reyes, Reinabelle; Zentner, Andrew R.

2014-03-06T23:59:59.000Z

236

Explicit computation of shear three-point correlation functions: the one-halo model case  

E-Print Network [OSTI]

We present a method for calculating explicit expressions of the shear three-point function for various cosmological models. The method is applied here to the one-halo model in case of power law density profiles for which results are detailed. The three-point functions are found to reproduce to a large extent patterns in the shear correlations obtained in numerical simulations and may serve as a guideline to implement optimized methods for detecting the shear three-point function. In principle, the general method presented here can also be applied for other models of matter correlation.

F. Bernardeau

2005-05-16T23:59:59.000Z

237

Massive Compact Halo Objects from the Relics of the Cosmic Quark-Hadron Transition  

E-Print Network [OSTI]

The existence of compact gravitational lenses, with masses around 0.5 (M_{\\odot}), has been reported in the halo of the Milky Way. The nature of these dark lenses is as yet obscure, particularly because these objects have masses well above the threshold for nuclear fusion. In this work, we show that they find a natural explanation as being the evolutionary product of the metastable false vacuum domains (the so-called strange quark nuggets) formed in a first order cosmic quark-hadron transition.

Shibaji Banerjee; Abhijit Bhattacharyya; Sanjay K. Ghosh; Sibaji Raha. Bikash Sinha; Hiroshi Toki

2002-11-26T23:59:59.000Z

238

Primordial pollution of globular clusters within their host dwarfs embedded in dark matter halos at high redshifts  

E-Print Network [OSTI]

Recent observational studies have revealed star-to-star abundance inhomogeneity among light elements (e.g., C, N, O, Na, and Al) of stars on the main sequence in the Galactic globular clusters (GCs). One of promising interpretations for this result is that the observed abundance inhomogeneity is due to the second generation of stars formed from ejecta of the first generation of evolved stars (e.g., AGB stars) within GCs. However it remains unclear whether and how this primordial pollution can occur within GCs. We here propose a new scenario in which primordial pollution of GCs is highly likely to occur if GCs are located in the central regions of high redshift dark matter subhalos that can host low-mass dwarf galaxies. In this scenario, gas ejected from the first generation of stars of GCs can be effectively trapped in the deep gravitational potential of their host halos and consequently can be consumed for the formation of the second generation of stars without losing a significant amount of gas by ram pressure stripping of interstellar and intergalactic medium. During merging of these halos with the proto-Galaxy, the halos are completely destroyed owing to the strong tidal field of the Galaxy. The self-polluted GCs located initially in the central regions of the halos can survive from tidal destruction owing to their compactness and finally become the Galactic halo GCs. In this scenario, ejecta of field stars surrounding the central GCs can be also converted into stars within their host dwarfs and finally become the second generation of stars of GCs. We also discuss the origin of the difference in the degree of abundance inhomogeneity between different GCs, such as $\\omega$ Centauri and NGC 6752, in terms of the difference in physical properties between host halos from which GC originate.

Kenji Bekki

2005-12-19T23:59:59.000Z

239

Photometry and the Metallicity Distribution of the Outer Halo of M31. II. The 30 Kpc Field  

E-Print Network [OSTI]

We present the results of a wide-field (V,I) photometric study of the red-giant branch (RGB) stars in the outer halo of M31, in a field located 30 to 35 kpc from the center of the galaxy along the southeast minor axis. At this remote location, we find that RGB stars belonging to M31 are sparsely but definitely present, after statistical subtraction of field contamination. We derive the metallicity distribution (MDF) for the halo stars using interpolation within a standard (I,V-I) grid of RGB evolutionary tracks. The halo MDF is quite broad but dominated by a moderately high-metallicity population peaking at [m/H] ~ -0.5, strikingly different from the [m/H] ~ -1.3 level which characterizes the outer halo of the Milky Way. However,the shape and peak metallicity for this region are entirely similar to those found in other studies for the inner regions of the M31 halo, particularly our previous study of a 20-kpc region (Durrell, Harris, & Pritchet 2001) employing similar data. In summary, we find no evidence for a metallicity gradient or systematic change in the MDF out to quite large distances in the M31 halo: it appears to be a homogeneous and moderately metal-rich subsystem of the galaxy at all locations. The star counts in the 30-kpc field are also consistent with the r^1/4 law that fits the interior regions of the M31 spheroid surface brightness profile. The metal-rich MDF and the r^1/4 spheroid suggests M31 more strongly resembles a giant elliptical galaxy than other, Milky-Way-like, spirals.

Patrick R. Durrell; William E. Harris; Christopher J. Pritchet

2004-05-20T23:59:59.000Z

240

Constraining the extension of a possible gamma-ray halo of 3C 279 from 2008-2014 solar occultations  

E-Print Network [OSTI]

The angular extension of the gamma-ray image of 3C 279 may be constrained by studying its solar occultations as suggested by Fairbairn et al. (2010). We perform this kind of analysis for seven occultations observed by Fermi-LAT in 2008-2014, using the Fermi-LAT Solar System tools. The results are interpreted in terms of models with extended gamma-ray halo of 3C 279; first constraints on the size and the flux of the halo are reported.

Kotelnikov, Egor; Troitsky, Sergey

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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

Magnesium Isotopes in Metal-Poor Dwarfs, the Rise of AGB Stars and the Formation Timescale of the Galactic Halo  

E-Print Network [OSTI]

We have determined magnesium isotopic ratios (^{25,26}Mg/Mg) in metal-poor (-2.6 [Fe/H] -1.3) halo dwarfs employing high S/N (90-280) high spectral resolution (R = 10^5) Keck HIRES spectra. Unlike previous claims of an important contribution from intermediate-mass AGB stars at low metallicities, we find that the rise of the AGB contribution in the Galactic halo did not occur until intermediate metallicities ([Fe/H] ~> -1.5).

Jorge Melendez; Judith G. Cohen

2007-02-24T23:59:59.000Z

242

A confirmed location in the Galactic halo for the high-velocity cloud 'chain A'  

E-Print Network [OSTI]

The high-velocity clouds of atomic hydrogen, discovered about 35 years ago, have velocities inconsistent with simple Galactic rotation models that generally fit the stars and gas in the Milky Way disk. Their origins and role in Galactic evolution remain poorly understood, largely for lack of information on their distances. The high-velocity clouds might result from gas blown from the Milky Way disk into the halo by supernovae, in which case they would enrich the Galaxy with heavy elements as they fall back onto the disk. Alternatively, they may consist of metal-poor gas -- remnants of the era of galaxy formation, accreted by the Galaxy and reducing its metal abundance. Or they might be truly extragalactic objects in the Local Group of galaxies. Here we report a firm distance bracket for a large high-velocity cloud, Chain A, which places it in the Milky Way halo (2.5 to 7 kiloparsecs above the Galactic plane), rather than at an extragalactic distance, and constrains its gas mass to between 10^5 and 2 times 10^6 solar masses.

Hugo van Woerden; Ulrich J. Schwarz; Reynier F. Peletier; Bart P. Wakker; Peter M. W. Kalberla

1999-07-08T23:59:59.000Z

243

A confirmed location in the Galactic halo for the high-velocity cloud "chain A"  

E-Print Network [OSTI]

The high-velocity clouds of atomic hydrogen, discovered about 35 years ago, have velocities inconsistent with simple Galactic rotation models that generally fit the stars and gas in the Milky Way disk. Their origins and role in Galactic evolution remain poorly understood, largely for lack of information on their distances. The high-velocity clouds might result from gas blown from the Milky Way disk into the halo by supernovae, in which case they would enrich the Galaxy with heavy elements as they fall back onto the disk. Alternatively, they may consist of metal-poor gas -- remnants of the era of galaxy formation, accreted by the Galaxy and reducing its metal abundance. Or they might be truly extragalactic objects in the Local Group of galaxies. Here we report a firm distance bracket for a large high-velocity cloud, Chain A, which places it in the Milky Way halo (2.5 to 7 kiloparsecs above the Galactic plane), rather than at an extragalactic distance, and constrains its gas mass to between 10^5 and 2 times 10^...

Van Woerden, H; Peletier, R F; Wakker, B P; Kalberla, P M W; Woerden, Hugo van; Schwarz, Ulrich J.; Peletier, Reynier F.; Wakker, Bart P.; Kalberla, Peter M.W.

1999-01-01T23:59:59.000Z

244

The structure of star clusters in the outer halo of M31  

E-Print Network [OSTI]

We present a structural analysis of halo star clusters in M31 based on deep Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) imaging. The clusters in our sample span a range in galactocentric projected distance from 13 to 100 kpc and thus reside in rather remote environments. Ten of the clusters are classical globulars, while four are from the Huxor et al. (2005, 2008) population of extended, old clusters. For most clusters, contamination by M31 halo stars is slight, and so the profiles can be mapped reliably to large radial distances from their centres. We find that the extended clusters are well fit by analytic King (1962) profiles with ~20 parsec core radii and ~100 parsec photometric tidal radii, or by Sersic profiles of index ~1 (i.e. approximately exponential). Most of the classical globulars also have large photometric tidal radii in the range 50-100 parsec, however the King profile is a less good fit in some cases, particularly at small radii. We find 60 of the classical globular cluster...

Tanvir, N R; Ferguson, A M N; Huxor, A; Read, J I; Lewis, G F; Irwin, M J; Chapman, S; Ibata, R; Wilkinson, M I; McConnachie, A W; Martin, N F; Davies, M B; Bridges, T J

2012-01-01T23:59:59.000Z

245

On the possible environmental effect in distributing heavy elements beyond individual gaseous halos  

E-Print Network [OSTI]

We present a study of extended galaxy halo gas through HI and OVI absorption over two decades in projected distance at $z\\approx0.2$. The study is based on a sample of $95$ galaxies from a highly complete ($ > 80\\%$) survey of faint galaxies ($L > 0.1L_*$) with archival quasar absorption spectra and $53$ galaxies from the literature. A clear anti-correlation is found between HI (OVI) column density and virial radius normalized projected distance, $d/R_{\\rm h}$. Strong HI (OVI) absorption systems with column densities greater than $10^{14.0}$ ($10^{13.5}$) cm$^{-2}$ are found for $48$ of $54$ ($36$ of $42$) galaxies at $d R_{\\rm h}$ compared to isolated galaxies ($\\kappa_{\\rm OVI}\\approx0.13$ versus $0.04$) but no excess HI absorption. These findings suggest that environmental effects play a role in distributing heavy elements beyond the enriched gaseous halos of individual galaxies. Finally, we find that differential HI and OVI absorption between early- and late-type galaxies continues from $d < R_{\\rm h}$...

Johnson, Sean D; Mulchaey, John S

2015-01-01T23:59:59.000Z

246

ON THE SIZE EVOLUTION OF A GALACTIC DISK IN HIERARCHICAL MERGING OF COLD DARK MATTER HALOS  

SciTech Connect (OSTI)

We investigate the dynamical effects of dark matter subhalos on the structure and evolution of a galactic disk, using the semi-analytic method that includes approximated and empirical relations as achieved in detailed numerical simulations of the cold dark matter model. We calculate the upper limit for the size of a galactic disk at a specific redshift z, based on the orbital properties of subhalos characterized by their pericentric distances from the center of a host halo. We find that this possibly largest size of a disk as determined by the smallest pericentric distances of subhalos shows the characteristic properties, which are basically in agreement with an observed galactic disk at low and high z. Namely, it is found that a massive disk can have a larger size than a less massive one, because of its stability against the destruction effect of subhalos. Also, with fixed mass, the size of a galactic disk at low z can be larger than that at high z, reflecting the orbital evolution of subhalos with respect to a host halo. These results suggest that the presence and structure of a galactic disk may be dynamically limited by the interaction with dark matter substructures, especially at high z.

Hayashi, Hirohito; Chiba, Masashi [Astronomical Institute, Tohoku University, Aoba-ku, Sendai 980-8578 (Japan)

2009-09-10T23:59:59.000Z

247

V474 Car: A RARE HALO RS CVn BINARY IN RETROGRADE GALACTIC ORBIT  

SciTech Connect (OSTI)

We report the discovery that the star V474 Car is an extremely active, high velocity halo RS CVn system. The star was originally identified as a possible pre-main-sequence star in Carina, given its enhanced stellar activity, rapid rotation (10.3 days), enhanced Li, and absolute magnitude which places it above the main sequence (MS). However, its extreme radial velocity (264 km s{sup -1}) suggested that this system was unlike any previously known pre-MS system. Our detailed spectroscopic analysis of echelle spectra taken with the CTIO 4 m finds that V474 Car is both a spectroscopic binary with an orbital period similar to the photometric rotation period and metal-poor ([Fe/H] {approx_equal}-0.99). The star's Galactic orbit is extremely eccentric (e {approx_equal} 0.93) with a perigalacticon of only {approx}0.3 kpc of the Galactic center-and the eccentricity and smallness of its perigalacticon are surpassed by only {approx}0.05% of local F/G-type field stars. The observed characteristics are consistent with V474 Car being a high-velocity, metal-poor, tidally locked, chromospherically active binary, i.e., a halo RS CVn binary, and one of only a few such specimens known.

Bubar, Eric J.; Mamajek, Eric E. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627-0171 (United States); Jensen, Eric L. N. [Swarthmore College, Department of Physics and Astronomy, 500 College Avenue, Swarthmore, PA 19081 (United States); Walter, Frederick M. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States)

2011-04-15T23:59:59.000Z

248

Discovery of an Unbound Hyper-Velocity Star in the Milky Way Halo  

E-Print Network [OSTI]

We have discovered a star, SDSS J090745.0+024507, leaving the Galaxy with a heliocentric radial velocity of +853+-12 km/s, the largest velocity ever observed in the Milky Way halo. The star is either a hot blue horizontal branch star or a B9 main sequence star with a heliocentric distance ~55 kpc. Corrected for the solar reflex motion and to the local standard of rest, the Galactic rest-frame velocity is +709 km/s. Because its radial velocity vector points 173.8 deg from the Galactic center, we suggest that this star is the first example of a hyper-velocity star ejected from the Galactic center as predicted by Hills and later discussed by Yu & Tremaine. The star has [Fe/H]~0, consistent with a Galactic center origin, and a travel time of <80 Myr from the Galactic center, consistent with its stellar lifetime. If the star is indeed traveling from the Galactic center, it should have a proper motion of 0.3 mas/yr observable with GAIA. Identifying additional hyper-velocity stars throughout the halo will constrain the production rate history of hyper-velocity stars at the Galactic center.

Warren R. Brown; Margaret J. Geller; Scott J. Kenyon; Michael J. Kurtz

2005-01-11T23:59:59.000Z

249

What to Bring to Lehigh Electric cooking appliances (including but not limited to coffee makers, toasters, toaster  

E-Print Network [OSTI]

, toasters, toaster ovens, grills, griddles, hot pots, hot plates) Portable heaters or air conditioners's license or ID card Storage bins, trunks or foot lockers Free-standing lamp (No halogen bulbs) Games snacks Water bottles Sewing kit #12;

Napier, Terrence

250

The Origin of the Hot Gas in the Galactic Halo: Testing Galactic Fountain Models' X-ray Emission  

E-Print Network [OSTI]

We test the X-ray emission predictions of galactic fountain models against XMM-Newton measurements of the emission from the Milky Way's hot halo. These measurements are from 110 sight lines, spanning the full range of Galactic longitudes. We find that a magnetohydrodynamical simulation of a supernova-driven interstellar medium, which features a flow of hot gas from the disk to the halo, reproduces the temperature but significantly underpredicts the 0.5-2.0 keV surface brightness of the halo (by two orders of magnitude, if we compare the median predicted and observed values). This is true for versions of the model with and without an interstellar magnetic field. We consider different reasons for the discrepancy between the model predictions and the observations. We find taking into account overionization in cooled halo plasma, which could in principle boost the predicted X-ray emission, is unlikely in practice to bring the predictions in line with the observations. We also find that including thermal conductio...

Henley, David B; Kwak, Kyujin; Hill, Alex S; Mac Low, Mordecai-Mark

2015-01-01T23:59:59.000Z

251

3D Spectroscopy of Wind Driven Nebulae: The Large Western Knot in the Halo of NGC 6543  

E-Print Network [OSTI]

spectroscopy 1 Introduction The history of stellar mass loss is written in the extended wind-driven nebulae would be required. A candidate for this extra energy source is the fast wind passing the cold3D Spectroscopy of Wind Driven Nebulae: The Large Western Knot in the Halo of NGC 6543 David Mart

Estalella, Robert

252

EXPLORING THE VARIABLE SKY WITH LINEAR. II. HALO STRUCTURE AND SUBSTRUCTURE TRACED BY RR LYRAE STARS TO 30 kpc  

SciTech Connect (OSTI)

We present a sample of {approx}5000 RR Lyrae stars selected from the recalibrated LINEAR data set and detected at heliocentric distances between 5 kpc and 30 kpc over {approx}8000 deg{sup 2} of sky. The coordinates and light curve properties, such as period and Oosterhoff type, are made publicly available. We analyze in detail the light curve properties and Galactic distribution of the subset of {approx}4000 type ab RR Lyrae (RRab) stars, including a search for new halo substructures and the number density distribution as a function of Oosterhoff type. We find evidence for the Oosterhoff dichotomy among field RR Lyrae stars, with the ratio of the type II and I subsamples of about 1:4, but with a weaker separation than for globular cluster stars. The wide sky coverage and depth of this sample allow unique constraints for the number density distribution of halo RRab stars as a function of galactocentric distance: it can be described as an oblate ellipsoid with an axis ratio q = 0.63 and with either a single or a double power law with a power-law index in the range -2 to -3. Consistent with previous studies, we find that the Oosterhoff type II subsample has a steeper number density profile than the Oosterhoff type I subsample. Using the group-finding algorithm EnLink, we detected seven candidate halo groups, only one of which is statistically spurious. Three of these groups are near globular clusters (M53/NGC 5053, M3, M13), and one is near a known halo substructure (Virgo Stellar Stream); the remaining three groups do not seem to be near any known halo substructures or globular clusters and seem to have a higher ratio of Oosterhoff type II to Oosterhoff type I RRab stars than what is found in the halo. The extended morphology and the position (outside the tidal radius) of some of the groups near globular clusters are suggestive of tidal streams possibly originating from globular clusters. Spectroscopic follow-up of detected halo groups is encouraged.

Sesar, Branimir [Division of Physics, Mathematics and Astronomy, Caltech, Pasadena, CA 91125 (United States); Ivezic, Zeljko; Morgan, Dylan M.; Becker, Andrew C. [University of Washington, Department of Astronomy, P.O. Box 351580, Seattle, WA 98195-1580 (United States); Stuart, J. Scott [Lincoln Laboratory, Massachusetts Institute of Technology, 244 Wood Street, Lexington, MA 02420-9108 (United States); Sharma, Sanjib [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Palaversa, Lovro [Observatoire astronomique de l'Universite de Geneve, 51 chemin des Maillettes, CH-1290 Sauverny (Switzerland); Juric, Mario [Steward Observatory, University of Arizona, Tucson, AZ 85121 (United States); Wozniak, Przemyslaw [Los Alamos National Laboratory, 30 Bikini Atoll Rd., Los Alamos, NM 87545-0001 (United States); Oluseyi, Hakeem [Florida Institute of Technology, Melbourne, FL 32901 (United States)

2013-08-01T23:59:59.000Z

253

GALAXY HALO TRUNCATION AND GIANT ARC SURFACE BRIGHTNESS RECONSTRUCTION IN THE CLUSTER MACSJ1206.2-0847  

SciTech Connect (OSTI)

In this work, we analyze the mass distribution of MACSJ1206.2-0847, particularly focusing on the halo properties of its cluster members. The cluster appears relaxed in its X-ray emission, but has a significant amount of intracluster light that is not centrally concentrated, suggesting that galaxy-scale interactions are still ongoing despite the overall relaxed state. The cluster lenses 12 background galaxies into multiple images and one galaxy at z = 1.033 into a giant arc and its counterimage. The multiple image positions and the surface brightness (SFB) distribution of the arc, which is bent around several cluster members, are sensitive to the cluster galaxy halo properties. We model the cluster mass distribution with a Navarro-Frenk-White profile and the galaxy halos with two parameters for the mass normalization and the extent of a reference halo assuming scalings with their observed near-infrared light. We match the multiple image positions at an rms level of 0.''85 and can reconstruct the SFB distribution of the arc in several filters to a remarkable accuracy based on this cluster model. The length scale where the enclosed galaxy halo mass is best constrained is about 5 effective radii-a scale in between those accessible to dynamical and field strong-lensing mass estimates on the one hand and galaxy-galaxy weak-lensing results on the other hand. The velocity dispersion and halo size of a galaxy with m{sub 160W,AB} = 19.2 and M{sub B,Vega} = -20.7 are {sigma} = 150 km s{sup -1} and r Almost-Equal-To 26 {+-} 6 kpc, respectively, indicating that the halos of the cluster galaxies are tidally stripped. We also reconstruct the unlensed source, which is smaller by a factor of {approx}5.8 in area, demonstrating the increase in morphological information due to lensing. We conclude that this galaxy likely has star-forming spiral arms with a red (older) central component.

Eichner, Thomas; Seitz, Stella; Monna, Anna [Universitaets-Sternwarte Muenchen, Scheinerstr. 1, D-81679 Muenchen (Germany); Suyu, Sherry H. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Halkola, Aleksi [Institute of Medical Engineering, University of Luebeck, Ratzeburger Allee 160 23562 Luebeck (Germany); Umetsu, Keiichi [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Zitrin, Adi [Institut fuer Theoretische Astrophysik, ZAH, Albert-Ueberle-Strasse 2, D-69120 Heidelberg (Germany); Coe, Dan; Postman, Marc; Koekemoer, Anton; Bradley, Larry [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21208 (United States); Rosati, Piero [ESO-European Southern Observatory, D-85748 Garching bei Muenchen (Germany); Grillo, Claudio; Host, Ole [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Balestra, Italo [Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Zheng, Wei; Lemze, Doron [Department of Physics and Astronomy, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Broadhurst, Tom [Department of Theoretical Physics, University of the Basque Country, P.O. Box 644, E-48080 Bilbao (Spain); Moustakas, Leonidas [Jet Propulsion Laboratory, California Institute of Technology, MS 169-327, Pasadena, CA 91109 (United States); Molino, Alberto [Instituto de Astrofisica de Andalucia (CSIC), C/Camino Bajo de Huetor 24, Granada E-18008 (Spain); and others

2013-09-10T23:59:59.000Z

254

Limits on the Macho Content of the Galactic Halo from the EROS-2 Survey of the Magellanic Clouds  

E-Print Network [OSTI]

The EROS-2 project was designed to test the hypothesis that massive compact halo objects (the so-called ``machos'') could be a major component of the dark matter halo of the Milky Way galaxy. To this end, EROS-2 monitored over 6.7 years $33\\times10^6$ stars in the Magellanic clouds for microlensing events caused by such objects. In this work, we use only a subsample of $7\\times10^6$ bright stars spread over $84 \\deg^2$ of the LMC and $9 \\deg^2$ of the SMC. The strategy of using only bright stars helps to discriminate against background events due to variable stars and allows a simple determination of the effects of source confusion (blending). The use of a large solid angle makes the survey relatively insensitive to effects that could make the optical depth strongly direction dependent. Using this sample of bright stars, only one candidate event was found, whereas $\\sim39$ events would have been expected if the Halo were entirely populated by objects of mass $M\\sim0.4M_{\\odot}$. Combined with the results of EROS-1, this implies that the optical depth toward the Large Magellanic Cloud (\\object{LMC}) due to such lenses is $\\tau<0.36\\times10^{-7}$ (95%CL), corresponding to a fraction of the halo mass of less than 8%. This optical depth is considerably less than that measured by the MACHO collaboration in the central region of the LMC. More generally, machos in the mass range $0.6\\times10^{-7}M_\\odotHalo.

P. Tisserand; L. Le Guillou; C. Afonso; J. N. Albert; J. Andersen; R. Ansari; E. Aubourg; P. Bareyre; J. P. Beaulieu; X. Charlot; C. Coutures; R. Ferlet; P. Fouqu; J. F. Glicenstein; B. Goldman; A. Gould; D. Graff; M. Gros; J. Haissinski; C. Hamadache; J. de Kat; T. Lasserre; E. Lesquoy; C. Loup; C. Magneville; J. B. Marquette; E. Maurice; A. Maury; A. Milsztajn; M. Moniez; N. Palanque-Delabrouille; O. Perdereau; Y. R. Rahal; J. Rich; M. Spiro; A. Vidal-Madjar; L. Vigroux; S. Zylberajch

2007-04-19T23:59:59.000Z

255

Applications of Cu{sub 2}O octahedral particles on ITO glass in photocatalytic degradation of dye pollutants under a halogen tungsten lamp  

SciTech Connect (OSTI)

Graphical abstract: - Highlights: Photocatalytic activity of Cu{sub 2}O octahedral microcrystals on ITO glass was studied. They showed high abilities in degradation of methylene blue in the presence of H{sub 2}O{sub 2}. H{sub 2}O{sub 2} amount could affect the degradation efficiency. Such particles could be easily recycled and still kept high activity. Many dye pollutants and their mixtures could be efficiently degraded. - Abstract: Cu{sub 2}O octahedral microcrystals were prepared on the ITO glass by galvanostatic electrodeposition in CuSO{sub 4} solution with poly(vinylpryrrolidone) as the surfactant. By controlling the electrodeposition time, the microcrystals could be randomly distributed on the ITO glass and separated from each other, resulting in as many as possible (1 1 1) crystalline planes were exposed. Such microcrystals immobilized on ITO glass were employed in photodegradation of dye pollutants in the presence of H{sub 2}O{sub 2} under a 150 W halogen tungsten lamp. The photodegradation of methylene blue was taken as an example to evaluate the photocatalytic activities of the octahedral Cu{sub 2}O microcrystals. Effects of electrodeposition time and H{sub 2}O{sub 2} amount on the degradation efficiency was discussed, giving the optimum conditions and the corresponding degradation mechanism. The catalyst showed high ability in degradation of methylene blue, methyl orange, rhodamine B, eosin B and their mixtures under identical conditions.

Zhai, Wei [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Sun, Fengqiang, E-mail: fqsun@scnu.edu.cn [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, South China Normal University (China); Exhibition Base of Production, Study and Research on New Polymer Materials and Postgraduate Students Innovation Training of Guangdong Higher Education Institutes (China); Chen, Wei; Zhang, Lihe; Min, Zhilin; Li, Weishan [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China)

2013-11-15T23:59:59.000Z

256

Globular Cluster Mass and Metallicity Distributions: Reconstructing the Events During Halo Formation  

E-Print Network [OSTI]

Globular clusters in most large galaxies are a mixture of metal-poor and metal-rich (bimodal), but the halo stars are almost entirely metal-rich. This and other lines of evidence argue that the metal-poor globular clusters formed within widely distributed 10^8-10^9 Solar masses gas clouds (supergiant GMCs) during an early burst in which most of the gas was ejected or unused till later rounds of star formation. New simulations of the growth of pre-galactic potential wells in the early universe now indicate that the initial power-law form of the globular cluster mass distribution (dN/dM ~ M^-1.8) is a miniature replica of the mass distribution of the SGMCs themselves, which grow hierarchically in the CDM potential wells of large protogalaxies.

W. E. Harris

2001-08-22T23:59:59.000Z

257

Cool carbon stars in the halo II. A study of 25 new objects  

E-Print Network [OSTI]

We present new results from an ongoing survey of carbon-rich asymptotic giant (AGB) stars in the halo of our Galaxy. After selecting candidates primarily through their 2MASS colours, slit spectroscopy was achieved at the ESO NTT telescope. Twenty-one new AGB carbon stars were discovered, increasing the total of presently known similar AGB C stars to about 120. A further four were observed again in order to confirm their carbon-rich nature and measure radial velocities. Two main findings emerge from this work. First, we found a C star located at about 130 kpc from the Sun and at b = -62 degrees. This distant star is remarkably close (5 kpc) to the principal plane of the Stream of the Sagittarius dwarf galaxy, and is likely to be a tracer of a distant poorly populated southern warp of the Stream. etc etc

N. Mauron; T. R. Kendall; K. Gigoyan

2005-06-22T23:59:59.000Z

258

Study on the One-Proton Halo Structure in $^{23}$Al  

E-Print Network [OSTI]

The Glauber theory has been used to investigate the reaction cross section of proton-rich nucleus $^{23}$Al. A core plus a proton structure is assumed for $^{23}$Al. HO-type density distribution is used for the core while the density distribution for the valence proton is calculated by solving the eigenvalue problem of Woods-Saxon potential. The transparency function in an analytical expression is obtained adopting multi-Gaussian expansion for the density distribution. Coulomb correction and finite-range interaction are introduced. This modified Glauber model is apt for halo nuclei. A dominate s-wave is suggested for the last proton in $^{23}$Al from our analysis which is possible in the RMF calculation.

D. Q. Fang; C. W. Ma; Y. G. Ma; X. Z. Cai; J. G. Chen; J. H. Chen; W. Guo; W. D. Tian; K. Wang; Y. B. Wei; T. Z. Yan; C. Zhong; J. X. Zuo; W. Q. Shen

2005-03-10T23:59:59.000Z

259

Detecting dark matter-dark energy coupling with the halo mass function  

E-Print Network [OSTI]

We use high-resolution simulations of large-scale structure formation to analyze the effects of interacting dark matter and dark energy on the evolution of the halo mass function. Using a chi-square likelihood analysis, we find significant differences in the mass function between models of coupled dark matter-dark energy and standard concordance cosmology Lambda-CDM out to redshift z=1.5. We also find a preliminary indication that the Dark Energy Survey should be able to distinguish these models from Lambda-CDM within its mass and redshift contraints. While we can distinguish the effects of these models from Lambda-CDM cosmologies with different fundamental parameters, DES will require independent measurements of sigma-8 to confirm these effects.

P. M. Sutter; P. M. Ricker

2008-10-03T23:59:59.000Z

260

THE HALO MASS FUNCTION FROM EXCURSION SET THEORY. III. NON-GAUSSIAN FLUCTUATIONS  

SciTech Connect (OSTI)

We compute the effect of primordial non-Gaussianity on the halo mass function, using excursion set theory. In the presence of non-Gaussianity, the stochastic evolution of the smoothed density field, as a function of the smoothing scale, is non-Markovian and beside 'local' terms that generalize Press-Schechter (PS) theory, there are also 'memory' terms, whose effect on the mass function can be computed using the formalism developed in the first paper of this series. We find that, when computing the effect of the three-point correlator on the mass function, a PS-like approach which consists in neglecting the cloud-in-cloud problem and in multiplying the final result by a fudge factor {approx_equal}2, is in principle not justified. When computed correctly in the framework of excursion set theory, in fact, the 'local' contribution vanishes (for all odd-point correlators the contribution of the image Gaussian cancels the PS contribution rather than adding up), and the result comes entirely from non-trivial memory terms which are absent in PS theory. However it turns out that, in the limit of large halo masses, where the effect of non-Gaussianity is more relevant, these memory terms give a contribution which is the same as that computed naively with PS theory, plus subleading terms depending on derivatives of the three-point correlator. We finally combine these results with the diffusive barrier model developed in the second paper of this series, and we find that the resulting mass function reproduces recent N-body simulations with non-Gaussian initial conditions, without the introduction of any ad hoc parameter.

Maggiore, Michele [Departement de Physique Theorique, Universite de Geneve, 24 quai Ansermet, CH-1211 Geneve (Switzerland); Riotto, Antonio [CERN, PH-TH Division, CH-1211, Geneve 23 (Switzerland)

2010-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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

Application of Hydrogen Assisted Lean Operation to Natural Gas-Fueled Reciprocating Engines (HALO)  

SciTech Connect (OSTI)

Two key challenges facing Natural Gas Engines used for cogeneration purposes are spark plug life and high NOx emissions. Using Hydrogen Assisted Lean Operation (HALO), these two keys issues are simultaneously addressed. HALO operation, as demonstrated in this project, allows stable engine operation to be achieved at ultra-lean (relative air/fuel ratios of 2) conditions, which virtually eliminates NOx production. NOx values of 10 ppm (0.07 g/bhp-hr NO) for 8% (LHV H2/LHV CH4) supplementation at an exhaust O2 level of 10% were demonstrated, which is a 98% NOx emissions reduction compared to the leanest unsupplemented operating condition. Spark ignition energy reduction (which will increase ignition system life) was carried out at an oxygen level of 9%, leading to a NOx emission level of 28 ppm (0.13 g/bhp-hr NO). The spark ignition energy reduction testing found that spark energy could be reduced 22% (from 151 mJ supplied to the coil) with 13% (LHV H2/LHV CH4) hydrogen supplementation, and even further reduced 27% with 17% hydrogen supplementation, with no reportable effect on NOx emissions for these conditions and with stable engine torque output. Another important result is that the combustion duration was shown to be only a function of hydrogen supplementation, not a function of ignition energy (until the ignitability limit was reached). The next logical step leading from these promising results is to see how much the spark energy reduction translates into increase in spark plug life, which may be accomplished by durability testing.

Chad Smutzer

2006-01-01T23:59:59.000Z

262

TURBULENCE AND RADIO MINI-HALOS IN THE SLOSHING CORES OF GALAXY CLUSTERS  

SciTech Connect (OSTI)

A number of relaxed, cool-core galaxy clusters exhibit diffuse, steep-spectrum radio sources in their central regions, known as radio mini-halos. It has been proposed that the relativistic electrons responsible for the emission have been reaccelerated by turbulence generated by the sloshing of the cool core gas. We present a high-resolution MHD simulation of gas sloshing in a galaxy cluster coupled with subgrid simulations of relativistic electron acceleration to test this hypothesis. Our simulation shows that the sloshing motions generate turbulence on the order of {delta}v {approx} 50-200 km s{sup -1} on spatial scales of {approx}50-100 kpc and below in the cool core region within the envelope of the sloshing cold fronts, whereas outside the cold fronts, there is negligible turbulence. This turbulence is potentially strong enough to reaccelerate relativistic electron seeds (with initial {gamma} {approx} 100-500) to {gamma} {approx} 10{sup 4} via damping of magnetosonic waves and non-resonant compression. The seed electrons could remain in the cluster from, e.g., past active galactic nucleus activity. In combination with the magnetic field amplification in the core, these electrons then produce diffuse radio synchrotron emission that is coincident with the region bounded by the sloshing cold fronts, as indeed observed in X-rays and the radio. The result holds for different initial spatial distributions of pre-existing relativistic electrons. The power and the steep spectral index ({alpha} Almost-Equal-To 1-2) of the resulting radio emission are consistent with observations of mini-halos, though the theoretical uncertainties of the acceleration mechanisms are high. We also produce simulated maps of inverse-Compton hard X-ray emission from the same population of relativistic electrons.

ZuHone, J. A.; Markevitch, M. [Astrophysics Science Division, Laboratory for High Energy Astrophysics, Code 662, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States)] [Astrophysics Science Division, Laboratory for High Energy Astrophysics, Code 662, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Brunetti, G. [INAF Istituto di Radioastronomia, Via Gobetti 101, I-40129 Bologna (Italy)] [INAF Istituto di Radioastronomia, Via Gobetti 101, I-40129 Bologna (Italy); Giacintucci, S. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States)] [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States)

2013-01-10T23:59:59.000Z

263

Updated 9/23/2010 HOW TO RECYCLE  

E-Print Network [OSTI]

/Copiers · Garbage · Gas Cylinders · Glass Bottles & Jars · Grease · Halogen Bulbs · Hardbound Books · Hazardous Waste · Helium Tanks · Imaging Units for Printers/Copiers · Incandescent Bulbs · Ink Jet Printer · Newspapers & Newsprint #12;Updated 9/23/2010 · Office Supplies · Oil · Packing Peanuts · Paint · Pallets

Clark, John

264

Collisions induced by halo and weakly bound nuclei around the Coulomb barrier: Results at INFN-LNS Catania  

SciTech Connect (OSTI)

The study of collisions around the Coulomb barrier induced by halo and/or weakly bound nuclei has been the object of many publications in the last years, since the peculiar structure of such nuclei can strongly affect the reaction dynamics. In this paper we will summarize some results on the above topic obtained by our group at INFN-LNS Catania. Results concerning the study of elastic scattering and different reaction mechanisms in collisions induced by the halo nuclei {sup 11}Be and {sup 6}He and by the weakly bound stable nuclei {sup 6,7}Li on a {sup 64}Zn target, at energies around the Coulomb barrier, will be presented. The conclusions of our studies will be compared with the ones of other authors, in order to show if clear systematic conclusions can be drawn from the different papers published in the literature so far.

Figuera, Pierpaolo [INFN Laboratorio Nazionale del Sud, Via S.Sofia 62, I95123 Catania (Italy)

2012-10-20T23:59:59.000Z

265

Chemical Evolution of the Galactic Halo through Supernova-Induced Star Formation and Its Implication for Population III Stars  

E-Print Network [OSTI]

A model for Galactic chemical evolution, driven by supernova-induced star formation, is formulated and used to examine the nature of the Galactic halo at early epochs. In this model, new stars are formed following each supernova event, thus their abundance pattern is determined by the combination of heavy elements ejected from the supernova itself and those elements which are already present in the interstellar gas swept up by the supernova remnant. The end result is a prediction of large scatter in the abundance ratios among low-metallicity stars, reflecting a different nucleosynthesis yield for each Type II supernova with a different progenitor mass. Formation of new stars is terminated when supernova remnants sweep up too little gas to form shells. We show from calculations based on the above scenario that (i) the observed [Fe/H] distribution for the Galactic halo field stars can be reproduced without effectively decreasing the heavy-element yields from Type II supernovae by some manipulation required by previous models (e.g., via mass loss from the early Galaxy, or later mixing with ``pristine'' hydrogen clouds), (ii) the large observed scatter in the abundance ratio [Eu/Fe] for the most metal-poor stars can also be reproduced, and (iii) the frequency distribution of stars in the [Eu/Fe]-[Fe/H] plane can be predicted. Our model suggests that the probability of identifying essentially metal-free stars (Population III) in the local halo is around one in 10^{3-4}, provided that star formation in the halo is confined to individual gas clouds with mass of 10^{6-7} Msun and that the initial mass function of metal-free stars is not significantly different from the Salpeter mass function.

Takuji Tsujimoto; Toshikazu Shigeyama; Yuzuru Yoshii

1999-05-06T23:59:59.000Z

266

NEW CONSTRAINTS ON THE GALACTIC HALO MAGNETIC FIELD USING ROTATION MEASURES OF EXTRAGALACTIC SOURCES TOWARD THE OUTER GALAXY  

SciTech Connect (OSTI)

We present a study of the Milky Way disk and halo magnetic field, determined from observations of Faraday rotation measure (RM) toward 641 polarized extragalactic radio sources in the Galactic longitude range 100 Degree-Sign -117 Degree-Sign , within 30 Degree-Sign of the Galactic plane. For |b| < 15 Degree-Sign , we observe a symmetric RM distribution about the Galactic plane. This is consistent with a disk field in the Perseus arm of even parity across the Galactic mid-plane. In the range 15 Degree-Sign < |b| < 30 Degree-Sign , we find median RMs of -15 {+-} 4 rad m{sup -2} and -62 {+-} 5 rad m{sup -2} in the northern and southern Galactic hemispheres, respectively. If the RM distribution is a signature of the large-scale field parallel to the Galactic plane, then this suggests that the halo magnetic field toward the outer Galaxy does not reverse direction across the mid-plane. The variation of RM as a function of Galactic latitude in this longitude range is such that RMs become more negative at larger |b|. This is consistent with an azimuthal magnetic field of strength 2 {mu}G (7 {mu}G) at a height 0.8-2 kpc above (below) the Galactic plane between the local and the Perseus spiral arm. We propose that the Milky Way could possess spiral-like halo magnetic fields similar to those observed in M51.

Mao, S. A. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); McClure-Griffiths, N. M. [Australia Telescope National Facility, CSIRO, Epping, NSW 1710 (Australia); Gaensler, B. M. [Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006 (Australia); Brown, J. C.; Van Eck, C. L.; Stil, J. M.; Taylor, A. R. [Department of Physics and Astronomy, and Institute for Space Imaging Science, University of Calgary, AB (Canada); Haverkorn, M. [Department of Astrophysics, Radboud University, P.O. Box 9010, 6500 GL Nijmegen (Netherlands); Kronberg, P. P. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Shukurov, A., E-mail: mao@astro.wisc.edu [School of Mathematics and Statistics, University of Newcastle, Newcastle upon Tyne, NE1 7RU (United Kingdom)

2012-08-10T23:59:59.000Z

267

The accretion history of dark matter halos III: A physical model for the concentration-mass relation  

E-Print Network [OSTI]

We present a semi-analytic, physically motivated model for dark matter halo concentration as a function of halo mass and redshift. The semi-analytic model is intimately based on hierarchical structure formation. It uses an analytic model for the halo mass accretion history, based on extended Press Schechter (EPS) theory, and an empirical relation between concentration and an appropriate definition of formation time obtained through fits to the results of numerical simulations. The resulting concentration-mass relations are tested against the simulations and do not exhibit an upturn at high masses or high redshifts as claimed by recent works. Because our semi-analytic model is based on EPS theory, it can be applied to wide ranges in mass, redshift and cosmology. We predict a change of slope in the z=0 concentration-mass relation at a mass scale of $10^{11}\\rm{M}_{\\odot}$, that is caused by the varying power in the density perturbations. We provide best-fitting expressions of the $c-M$ relations as well as nume...

Correa, Camila A; Schaye, Joop; Duffy, Alan R

2015-01-01T23:59:59.000Z

268

Limits on the Macho Content of the Galactic Halo from the EROS-2 Survey of the Magellanic Clouds  

E-Print Network [OSTI]

The EROS-2 project was designed to test the hypothesis that massive compact halo objects (the so-called ``machos'') could be a major component of the dark matter halo of the Milky Way galaxy. To this end, EROS-2 monitored millions of stars in the Magellanic clouds for microlensing events caused by such objects. About $33\\times10^6$ Magellanic stars were observed over a period of 6.7 years. Unlike all previous studies of Magellanic microlensing, we use only a subsample of $7\\times10^6$ bright stars. This strategy minimizes backgrounds due to variable stars and ensures accurate determination of lensing parameters by minimizing source confusion (blending). Using this sample of bright stars, only one candidate event was found, whereas $\\sim42$ events would have been expected if the Halo were entirely populated by objects of mass $M\\sim0.4M_{\\odot}$. Combined with the results of EROS-1, this implies that the optical depth toward the Large Magellanic Cloud (\\object{LMC}) due to such lenses is $\\tau<0.36\\times10^...

Tisserand, P; Afonso, C; Albert, J N; Andersen, J; Ansari, R; Aubourg, E; Bareyre, P; Beaulieu, J P; Charlot, X; Coutures, C; Ferlet, R; Fouqu, P; Glicenstein, J F; Goldman, B; Gould, A; Graff, D; Gros, M; Hassinski, J; Hamadache, C; De Kat, J; Lasserre, T; Lesquoy, E; Loup, C; Magneville, C; Marquette, J B; Maurice, E; Maury, A; Milsztajn, A; Moniez, M; Palanque-Delabrouille, Nathalie; Perdereau, O; Rahal, Y R; Rich, J; Spiro, M; Vidal-Madjar, A; Vigroux, L; Zylberajch, S

2006-01-01T23:59:59.000Z

269

The Spatial Clustering of ROSAT All-Sky Survey AGNs II. Halo Occupation Distribution Modeling of the Cross Correlation Function  

E-Print Network [OSTI]

This is the second paper of a series that reports on our investigation of the clustering properties of AGNs in the ROSAT All-Sky Survey (RASS) through cross-correlation functions (CCFs) with Sloan Digital Sky Survey (SDSS) galaxies. In this paper, we apply the Halo Occupation Distribution (HOD) model to the CCFs between the RASS Broad-line AGNs with SDSS Luminous Red Galaxies (LRGs) in the redshift range 0.16halo mass, M_h, and model the full distribution function of AGN host dark matter halos. In addition, we are able to determine the large-scale bias and the mean M_h more accurately. We explore the behavior of three simple HOD models. Our first model (Model A) is a truncated power-law HOD model in which all AGNs are satellites. With this model, we find an upper lim...

Miyaji, Takamitsu; Coil, Alison L; Aceves, Hector

2010-01-01T23:59:59.000Z

270

Quantifying the heart of darkness with GHALO - a multi-billion particle simulation of our galactic halo  

E-Print Network [OSTI]

We perform a series of simulations of a Galactic mass dark matter halo at different resolutions, our largest uses over three billion particles and has a mass resolution of 1000 M_sun. We quantify the structural properties of the inner dark matter distribution and study how they depend on numerical resolution. We can measure the density profile to a distance of 120 pc (0.05% of R_vir) where the logarithmic slope is -0.8 and -1.4 at (0.5% of R_vir). We propose a new two parameter fitting function that has a linearly varying logarithmic density gradient which fits the GHALO and VL2 density profiles extremely well. Convergence in the density profile and the halo shape scales as N^(-1/3), but the shape converges at a radius three times larger at which point the halo becomes more spherical due to numerical resolution. The six dimensional phase-space profile is dominated by the presence of the substructures and does not follow a power law, except in the smooth under-resolved inner few kpc.

Joachim Stadel; Doug Potter; Ben Moore; Jrg Diemand; Piero Madau; Marcel Zemp; Michael Kuhlen; Vicent Quilis

2008-08-22T23:59:59.000Z

271

Qualitative and analytical results of the bifurcanion thresholds to halo orbits  

E-Print Network [OSTI]

We study the dynamics in the neighborhood of the collinear Lagrangian points in the spatial, circular, restricted three--body problem. We consider the case in which one of the primaries is a radiating body and the other is oblate (although the latter is a minor effect). Beside having an intrinsic mathematical interest, this model is particularly suited for the description of a mission of a spacecraft (e.g., a solar sail) to an asteroid. The aim of our study is to investigate the occurrence of bifurcations to halo orbits, which take place as the energy level is varied. The estimate of the bifurcation thresholds is performed by analytical and numerical methods: we find a remarkable agreement between the two approaches. As a side result, we also evaluate the influence of the different parameters, most notably the solar radiation pressure coefficient, on the dynamical behavior of the model. To perform the analytical and numerical computations, we start by implementing a center manifold reduction. Next, we estimate the bifurcation values using qualitative techniques (e.g. Poincar\\'e surfaces, frequency analysis, FLIs). Concerning the analytical approach, following \\cite{CPS} we implement a resonant normal form, we transform to suitable action-angle variables and we introduce a detuning parameter measuring the displacement from the synchronous resonance. The bifurcation thresholds are then determined as series expansions in the detuning. Three concrete examples are considered and we find in all cases a very good agreement between the analytical and numerical results.

Sara Bucciarelli; Marta Ceccaroni; Alessandra Celletti; Giuseppe Pucacco

2015-01-23T23:59:59.000Z

272

The Cosmological Quark-Hadron Transition and Massive Compact Halo Objects  

E-Print Network [OSTI]

One of the abiding mysteries in the so-called standard cosmological model is the nature of the dark matter. It is universally accepted that there is an abundance of matter in the universe which is non-luminous, due to their very weak interaction, if at all, with the other forms of matter, excepting of course the gravitational attraction. Speculations as to the nature of dark matter are numerous, often bordering on exotics, and searches for such exotic matter is a very active field of astroparticle physics at the dawn of the new century. Nevertheless, in recent years, there has been experimental evidence for at least one form of dark matter - the massive compact halo objects detected through gravitational microlensing effects proposed by Paczynski some years ago. To date, no clear consensus as to what these objects, referred to in the literature as well as in the following by the acronym MACHO, are made of; for a brief discussion of some of the suggestions, see below. In this work, we show that they find a natural explanation as leftover relics from the putative first order cosmic quark - hadron phase transition that is predicted by the standard model of particle interactions to have occurred during the microsecond epoch of the early universe.

Shibaji Banerjee; Abhijit Bhattacharyya; Sanjay K. Ghosh; Sibaji Raha; Bikash Sinha

2000-02-01T23:59:59.000Z

273

Power-laws and Non-Power-laws in Dark Matter Halos  

E-Print Network [OSTI]

Simulated dark matter profiles are often modelled as a `NFW' density profile rather than a single power law. Recently, attention has turned to the rather rigorous power-law behaviour exhibited by the `pseudo phase-space density' of the dark matter halo, which is defined dimensionally in terms of the local density and velocity dispersion of the dark matter particles. The non-power-law behaviour of the density profile is generally taken to exclude simple scale-free, in-fall models; however the power-law behaviour of the `pseudo-density' is a counter indication. We argue in this paper that both behaviours may be at least qualitatively understood in terms of a dynamically evolving self-similarity, rather than the form for self-similar infall that is fixed by cosmological initial conditions. The evolution is likely due to collective relaxation such as that provided by the radial-orbit instability on large scales. We deduce, from a distribution function given by first order coarse-graining, both the NFW-type density profile and the power-law pseudo-density profile. The results are not greatly sensitive to variation about 3 in the power of the velocity dispersion used in the definition of the phase space pseudo-density. We suggest that the power 2 may create the more physical quantity, whose deviations from a power-law are a diagnostic of incomplete relaxation.

R. N. Henriksen

2006-09-05T23:59:59.000Z

274

Assessing inflow rates in atomic cooling halos: implications for direct collapse black holes  

E-Print Network [OSTI]

Supermassive black holes are not only common in the present-day galaxies, but billion solar masses black holes also powered $z\\geq 6$ quasars. One efficient way to form such black holes is the collapse of a massive primordial gas cloud into a so-called direct collapse black hole. The main requirement for this scenario is the presence of large accretion rates of $\\rm \\geq 0.1~M_{\\odot}/yr$ to form a supermassive star. The prime aim of the present work is to determine how and under what conditions such accretion rates can be obtained. We perform high resolution cosmological simulations for three primordial halos of a few times $\\rm 10^7~M_{\\odot}$ illuminated by an external UV flux, $\\rm J_{21}=100-1000$. We find that a rotationally supported structure of about parsec size is assembled, with an aspect ratio between $\\rm 0.25 - 1$ depending upon the thermodynamical properties. Rotational support, however, does not halt collapse, and mass inflow rates of $\\rm \\sim 0.1~M_{\\odot}/yr$ can be obtained in the presence...

Latif, M A

2015-01-01T23:59:59.000Z

275

Qualitative and analytical results of the bifurcation thresholds to halo orbits  

E-Print Network [OSTI]

We study the dynamics in the neighborhood of the collinear Lagrangian points in the spatial, circular, restricted three--body problem. We consider the case in which one of the primaries is a radiating body and the other is oblate (although the latter is a minor effect). Beside having an intrinsic mathematical interest, this model is particularly suited for the description of a mission of a spacecraft (e.g., a solar sail) to an asteroid. The aim of our study is to investigate the occurrence of bifurcations to halo orbits, which take place as the energy level is varied. The estimate of the bifurcation thresholds is performed by analytical and numerical methods: we find a remarkable agreement between the two approaches. As a side result, we also evaluate the influence of the different parameters, most notably the solar radiation pressure coefficient, on the dynamical behavior of the model. To perform the analytical and numerical computations, we start by implementing a center manifold reduction. Next, we estimate the bifurcation values using qualitative techniques (e.g. Poincar\\'e surfaces, frequency analysis, FLIs). Concerning the analytical approach, following \\cite{CPS} we implement a resonant normal form, we transform to suitable action-angle variables and we introduce a detuning parameter measuring the displacement from the synchronous resonance. The bifurcation thresholds are then determined as series expansions in the detuning. Three concrete examples are considered and we find in all cases a very good agreement between the analytical and numerical results.

Sara Bucciarelli; Marta Ceccaroni; Alessandra Celletti; Giuseppe Pucacco

2015-02-01T23:59:59.000Z

276

EXTENDED HOT HALOS AROUND ISOLATED GALAXIES OBSERVED IN THE ROSAT ALL-SKY SURVEY  

SciTech Connect (OSTI)

We place general constraints on the luminosity and mass of hot X-ray-emitting gas residing in extended 'hot halos' around nearby massive galaxies. We examine stacked images of 2165 galaxies from the 2MASS Isolated Galaxy Catalog as well as subsets of this sample based on galaxy morphology and K-band luminosity. We detect X-ray emission at high confidence (ranging up to nearly 10{sigma}) for each subsample of galaxies. The average L{sub X} within 50 kpc is 1.0 {+-} 0.1 (statistical) {+-}0.2 (systematic) Multiplication-Sign 10{sup 40} erg s{sup -1}, although the early-type galaxies are more than twice as luminous as the late-type galaxies. Using a spatial analysis, we also find evidence for extended emission around five out of seven subsamples (the full sample, the luminous galaxies, early-type galaxies, luminous late-type galaxies, and luminous early-type galaxies) at 92.7%, 99.3%, 89.3%, 98.7%, and 92.1% confidence, respectively. Several additional lines of evidence also support this conclusion and suggest that about 1/2 of the total emission is extended, and about 1/3 of the extended emission comes from hot gas. For the sample of luminous galaxies, which has the strongest evidence for extended emission, the average hot gas mass is 4 Multiplication-Sign 10{sup 9} M {sub Sun} within 50 kpc and the implied accretion rate is 0.4 M {sub Sun} yr{sup -1}.

Anderson, Michael E.; Bregman, Joel N. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States)] [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Dai, Xinyu, E-mail: michevan@umich.edu, E-mail: jbregman@umich.edu, E-mail: xdai@ou.edu [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States)] [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States)

2013-01-10T23:59:59.000Z

277

Evolution of the luminosity-to-halo mass relation of LRGs from a combined SDSS-DR10+RCS2 analysis  

E-Print Network [OSTI]

We study the evolution of the luminosity-to-halo mass relation of Luminous Red Galaxies (LRGs). We select a sample of 52 000 LOWZ and CMASS LRGs from the Baryon Oscillation Spectroscopic Survey (BOSS) SDSS-DR10 in the ~450 deg^2 that overlaps with imaging data from the second Red-sequence Cluster Survey (RCS2), group them into bins of absolute magnitude and redshift and measure their weak lensing signals. The source redshift distribution has a median of 0.7, which allows us to study the lensing signal as a function of lens redshift. We interpret the lensing signal using a halo model, from which we obtain the halo masses as well as the normalisations of the mass-concentration relations. We find that the concentration of haloes that host LRGs is consistent with dark matter only simulations once we allow for miscentering or satellites in the modelling. The slope of the luminosity-to-halo mass relation has a typical value of 1.4 and does not change with redshift, but we do find evidence for a change in amplitude:...

van Uitert, Edo; Hoekstra, Henk; Herbonnet, Ricardo

2015-01-01T23:59:59.000Z

278

Mon. Not. R. Astron. Soc. 410, 210226 (2011) doi:10.1111/j.1365-2966.2010.17436.x Satellite kinematics III. Halo masses of central galaxies in SDSS  

E-Print Network [OSTI]

matter. The fluctuations in the dark matter density field grow under the action of gravity and form a web that orbit around the central galaxy in a dark matter halo to infer the scaling relations between halo mass of 2), indicating that we are converging on an accurate and reliable description of the galaxy­dark

Skibba, Ramin A.

279

A Model of the EGRET Source at the Galactic Center: Inverse Compton Scattering Within Sgr A East and its Halo  

E-Print Network [OSTI]

Continuum low-frequency radio observations of the Galactic Center reveal the presence of two prominent radio sources, Sgr A East and its surrounding Halo, containing non-thermal particle distributions with power-law indices around 2.5-3.3 and 2.4, respectively. The central 1-2 pc region is also a source of intense (stellar) UV and (dust-reprocessed) far-IR radiation that bathes these extended synchrotron-emitting structures. A recent detection of gamma-rays (2EGJ1746-2852) from within around 1 degree of the Galactic Center by EGRET onboard the Compton GRO shows that the emission from this environment extends to very high energies. We suggest that inverse Compton scatterings between the power-law electrons inferred from the radio properties of Sgr A East and its Halo, and the UV and IR photons from the nucleus, may account for the possibly diffuse gamma-ray source as well. We show that both particle distributions may be contributing to the gamma-ray emission, though their relevant strength depends on the actual physical properties (such as the magnetic field intensity) in each source. If this picture is correct, the high-energy source at the Galactic Center is extended over several arcminutes, which can be tested with thenext generation of gamma-ray and hard X-ray missions.

Fulvio Melia; Farhad Yusef-Zadeh; Marco Fatuzzo

1998-06-24T23:59:59.000Z

280

Baryon Cycling in the Low-Redshift Circumgalactic Medium: A Comparison of Simulations to the COS-Halos Survey  

E-Print Network [OSTI]

We analyze the low-redshift (z~0.2) circumgalactic medium by comparing absorption-line data from the COS-Halos Survey to absorption around a matched galaxy sample from two cosmological hydrodynamic simulations. The models include different prescriptions for galactic outflows, namely hybrid energy/momentum driven wind (ezw), and constant winds (cw). We extract for comparison direct observables including equivalent widths, covering factors, ion ratios, and kinematics. Both wind models are generally in good agreement with these observations for HI and certain low ionization metal lines, but show poorer agreement with higher ionization metal lines including SiIII and OVI that are well-observed by COS-Halos. These discrepancies suggest that both wind models predict too much cool, metal-enriched gas and not enough hot gas, and/or that the metals are not sufficiently well-mixed. This may reflect our model assumption of ejecting outflows as cool and unmixing gas. Our ezw simulation includes a heuristic prescription t...

Ford, Amanda Brady; Dave, Romeel; Tumlinson, Jason; Bordoloi, Rongmon; Katz, Neal; Kollmeier, Juna A; Oppenheimer, Benjamin D; Peeples, Molly S; Prochaska, Jason X; Weinberg, David H

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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

The build-up of the cD halo of M87 - evidence for accretion in the last Gyr  

E-Print Network [OSTI]

We present kinematic and photometric evidence for an accretion event in the halo of the cD galaxy M87 in the last Gyr. Using velocities for ~300 planetary nebulas (PNs) in the M87 halo, we identify a chevron-like substructure in the PN phase-space. We implement a probabilistic Gaussian mixture model to identify the PNs that belong to the chevron. From analysis of deep V-band images of M87, we find that the region with the highest density of PNs associated to the chevron, is a crown-shaped substructure in the optical light. We assign a total of N_(PN,sub)=54 to the substructure, which extends over ~50 kpc along the major axis where we also observe radial variations of the ellipticity profile and a colour gradient. The substructure has highest surface brightness in a 20kpc x 60kpc region around 70 kpc in radius. In this region, it causes an increase in surface brightness by >60%. The accretion event is consistent with a progenitor galaxy with a V-band luminosity of L=2.8\\pm1.0 x 10^9 L_(sun,V), a colour of (B-V...

Longobardi, A; Gerhard, O; Mihos, J C

2015-01-01T23:59:59.000Z

282

The Outer Halo of the Nearest Giant Elliptical: A VLT/VIMOS Survey of the Resolved Stellar Populations in Centaurus A to 85 kpc  

E-Print Network [OSTI]

We present the first deep survey of resolved stellar populations in the remote outer halo of our nearest giant elliptical (gE), Centaurus A (D=3.8 Mpc). Using the VIMOS/VLT optical camera, we obtained deep photometry for four fields along the major and minor axes at projected elliptical radii of ~30-85 kpc (corresponding to ~5-14 R_{eff}). We use resolved star counts to map the spatial and colour distribution of red giant branch (RGB) stars down to ~2 magnitudes below the RGB tip. We detect an extended halo out to the furthermost elliptical radius probed (~85 kpc or ~14 R_{eff}), demonstrating the vast extent of this system. We detect a localised substructure in these parts, visible in both (old) RGB and (intermediate-age) luminous asymptotic giant branch stars, and there is some evidence that the outer halo becomes more elliptical and has a shallower surface brightness profile. We derive photometric metallicity distribution functions for halo RGB stars and find relatively high median metallicity values ([Fe/...

Crnojevi?, D; Irwin, M J; Bernard, E J; Arimoto, N; Jablonka, P; Kobayashi, C

2013-01-01T23:59:59.000Z

283

Unique decay process: {beta}-delayed emission of a proton and a neutron by the {sup 11}Li halo nucleus  

SciTech Connect (OSTI)

The neutron-rich {sup 11}Li halo nucleus is unique among nuclei with known separation energies in its ability to emit a proton and a neutron in a {beta}-decay process. The branching ratio toward this rare decay mode is evaluated within a three-body model for the initial bound state and with Coulomb three-body final scattering states. The branching ratio should be comprised between two extreme cases, i.e., a lower bound 6x10{sup -12} obtained with a pure Coulomb wave and an upper bound 5x10{sup -10} obtained with a plane wave. A simple model with modified Coulomb waves provides plausible values between 0.8x10{sup -10} and 2.2x10{sup -10}, with most probable total energies of the proton and neutron between 0.15 and 0.3 MeV.

Baye, D.; Descouvemont, P.; Tursunov, E. M. [Physique Quantique, CP 165/82, and Physique Nucleaire Theorique et Physique Mathematique, CP 229, Universite Libre de Bruxelles (ULB), B-1050 Brussels (Belgium); Institute of Nuclear Physics, Uzbekistan Academy of Sciences, 100214, Ulugbek, Tashkent (Uzbekistan)

2010-11-15T23:59:59.000Z

284

A unique decay process: beta delayed emission of a proton and a neutron by the $^{11}$Li halo nucleus  

E-Print Network [OSTI]

The neutron-rich $^{11}$Li halo nucleus is unique among nuclei with known separation energies by its ability to emit a proton and a neutron in a $\\beta$ decay process. The branching ratio towards this rare decay mode is evaluated within a three-body model for the initial bound state and with Coulomb three-body final scattering states. The branching ratio should be comprised between two extreme cases, i.e.\\ a lower bound $6 \\times 10^{-12}$ obtained with a pure Coulomb wave and an upper bound $5 \\times 10^{-10}$ obtained with a plane wave. A simple model with modified Coulomb waves provides plausible values between between $0.8 \\times 10^{-10}$ and $2.2 \\times 10^{-10}$ with most probable total energies of the proton and neutron between 0.15 and 0.3 MeV.

Baye, D; Tursunov, E M

2010-01-01T23:59:59.000Z

285

A unique decay process: beta delayed emission of a proton and a neutron by the $^{11}$Li halo nucleus  

E-Print Network [OSTI]

The neutron-rich $^{11}$Li halo nucleus is unique among nuclei with known separation energies by its ability to emit a proton and a neutron in a $\\beta$ decay process. The branching ratio towards this rare decay mode is evaluated within a three-body model for the initial bound state and with Coulomb three-body final scattering states. The branching ratio should be comprised between two extreme cases, i.e.\\ a lower bound $6 \\times 10^{-12}$ obtained with a pure Coulomb wave and an upper bound $5 \\times 10^{-10}$ obtained with a plane wave. A simple model with modified Coulomb waves provides plausible values between between $0.8 \\times 10^{-10}$ and $2.2 \\times 10^{-10}$ with most probable total energies of the proton and neutron between 0.15 and 0.3 MeV.

D. Baye; P. Descouvemont; E. M. Tursunov

2010-12-28T23:59:59.000Z

286

MEASURING THE ULTIMATE HALO MASS OF GALAXY CLUSTERS: REDSHIFTS AND MASS PROFILES FROM THE HECTOSPEC CLUSTER SURVEY (HeCS)  

SciTech Connect (OSTI)

The infall regions of galaxy clusters represent the largest gravitationally bound structures in a {Lambda}CDM universe. Measuring cluster mass profiles into the infall regions provides an estimate of the ultimate mass of these halos. We use the caustic technique to measure cluster mass profiles from galaxy redshifts obtained with the Hectospec Cluster Survey (HeCS), an extensive spectroscopic survey of galaxy clusters with MMT/Hectospec. We survey 58 clusters selected by X-ray flux at 0.1 < z < 0.3. The survey includes 22,680 unique MMT/Hectospec redshifts for individual galaxies; 10,145 of these galaxies are cluster members. For each cluster, we acquired high signal-to-noise spectra for {approx}200 cluster members and a comparable number of foreground/background galaxies. The cluster members trace out infall patterns around the clusters. The members define a very narrow red sequence. We demonstrate that the determination of velocity dispersion is insensitive to the inclusion of bluer members (a small fraction of the cluster population). We apply the caustic technique to define membership and estimate the mass profiles to large radii. The ultimate halo mass of clusters (the mass that remains bound in the far future of a {Lambda}CDM universe) is on average (1.99 {+-} 0.11)M{sub 200}, a new observational cosmological test in essential agreement with simulations. Summed profiles binned in M{sub 200} and in L{sub X} demonstrate that the predicted Navarro-Frenk-White form of the density profile is a remarkably good representation of the data in agreement with weak lensing results extending to large radius. The concentration of these summed profiles is also consistent with theoretical predictions.

Rines, Kenneth [Department of Physics and Astronomy, Western Washington University, Bellingham, WA 98225 (United States)] [Department of Physics and Astronomy, Western Washington University, Bellingham, WA 98225 (United States); Geller, Margaret J.; Kurtz, Michael J. [Smithsonian Astrophysical Observatory, 60 Garden Street, MS 20, Cambridge, MA 02138 (United States)] [Smithsonian Astrophysical Observatory, 60 Garden Street, MS 20, Cambridge, MA 02138 (United States); Diaferio, Antonaldo, E-mail: kenneth.rines@wwu.edu, E-mail: diaferio@ph.unito.it [Dipartimento di Fisica, Universita di Torino, Torino (Italy)] [Dipartimento di Fisica, Universita di Torino, Torino (Italy)

2013-04-10T23:59:59.000Z

287

Ceramic Mugs & Dishes Incandescent Light Bulbs  

E-Print Network [OSTI]

, MU East Rock Hall/19-B CELL PHONES - EYEGLASSES 654 Minnesota Street Room 208, copy room CVRI Helen. Zion Cancer Research Building N423 Parnassus Campus: eyeglasses "I" level, Optometry Store, MU West

Yamamoto, Keith

288

Neutron Halo Isomers in Stable Nuclei and their Possible Application for the Production of Low Energy, Pulsed, Polarized Neutron Beams of High Intensity and High Brilliance  

E-Print Network [OSTI]

We propose to search for neutron halo isomers populated via $\\gamma$-capture in stable nuclei with mass numbers of about A=140-180 or A=40-60, where the $4s_{1/2}$ or $3s_{1/2}$ neutron shell model state reaches zero binding energy. These halo nuclei can be produced for the first time with new $\\gamma$-beams of high intensity and small band width ($\\le$ 0.1%) achievable via Compton back-scattering off brilliant electron beams thus offering a promising perspective to selectively populate these isomers with small separation energies of 1 eV to a few keV. Similar to single-neutron halo states for very light, extremely neutron-rich, radioactive nuclei \\cite{hansen95,tanihata96,aumann00}, the low neutron separation energy and short-range nuclear force allows the neutron to tunnel far out into free space much beyond the nuclear core radius. This results in prolonged half lives of the isomers for the $\\gamma$-decay back to the ground state in the 100 ps-$\\mu$s range. Similar to the treatment of photodisintegration of the deuteron, the neutron release from the neutron halo isomer via a second, low-energy, intense photon beam has a known much larger cross section with a typical energy threshold behavior. In the second step, the neutrons can be released as a low-energy, pulsed, polarized neutron beam of high intensity and high brilliance, possibly being much superior to presently existing beams from reactors or spallation neutron sources.

D. Habs; M. Gross; P. G. Thirolf; P. Bni

2010-09-30T23:59:59.000Z

289

PAndAS IN THE MIST: THE STELLAR AND GASEOUS MASS WITHIN THE HALOS OF M31 AND M33  

SciTech Connect (OSTI)

Large-scale surveys of the prominent members of the Local Group have provided compelling evidence for the hierarchical formation of massive galaxies, revealing a wealth of substructure that is thought to be the debris from ancient and ongoing accretion events. In this paper, we compare two extant surveys of the M31-M33 subgroup of galaxies: the Pan-Andromeda Archaeological Survey of the stellar structure, and a combination of observations of the H I gaseous content, detected at 21 cm. Our key finding is a marked lack of spatial correlation between these two components on all scales, with only a few potential overlaps between stars and gas. The paucity of spatial correlation significantly restricts the analysis of kinematic correlations, although there does appear to be H I kinematically associated with the Giant Stellar Stream where it passes the disk of M31. These results demonstrate that different processes must significantly influence the dynamical evolution of the stellar and H I components of substructures, such as ram pressure driving gas away from a purely gravitational path. Detailed modeling of the offset between the stellar and gaseous substructures will provide a determination of the properties of the gaseous halos of M31 and M33.

Lewis, Geraint F. [Sydney Institute for Astronomy, School of Physics A28, The University of Sydney, NSW 2006 (Australia)] [Sydney Institute for Astronomy, School of Physics A28, The University of Sydney, NSW 2006 (Australia); Braun, Robert [CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia)] [CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia); McConnachie, Alan W. [Dominion Astrophysical Observatory, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada)] [Dominion Astrophysical Observatory, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Irwin, Michael J.; Chapman, Scott C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)] [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Ibata, Rodrigo A.; Martin, Nicolas F. [Observatoire de Strasbourg, 11, rue de l'Universite, F-67000 Strasbourg (France)] [Observatoire de Strasbourg, 11, rue de l'Universite, F-67000 Strasbourg (France); Ferguson, Annette M. N. [Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)] [Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Fardal, Mark [Department of Astronomy, University of Massachusetts, Amherst, MA 01003-9305 (United States)] [Department of Astronomy, University of Massachusetts, Amherst, MA 01003-9305 (United States); Dubinski, John [Department of Astronomy and Astrophysics, 50 St. George Street, University of Toronto, ON M5S 3H4 (Canada)] [Department of Astronomy and Astrophysics, 50 St. George Street, University of Toronto, ON M5S 3H4 (Canada); Widrow, Larry [Department of Physics, Queen's University, 99 University Avenue, Kingston, ON K7L 3N6 (Canada)] [Department of Physics, Queen's University, 99 University Avenue, Kingston, ON K7L 3N6 (Canada); Mackey, A. Dougal [Research School of Astronomy and Astrophysics, Mount Stromlo Observatory, Cotter Road, Weston Creek, ACT 2611 (Australia)] [Research School of Astronomy and Astrophysics, Mount Stromlo Observatory, Cotter Road, Weston Creek, ACT 2611 (Australia); Babul, Arif [Department of Physics and Astronomy, University of Victoria, Victoria, BC V8W 3P6 (Canada)] [Department of Physics and Astronomy, University of Victoria, Victoria, BC V8W 3P6 (Canada); Tanvir, Nial R. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom)] [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Rich, Michael, E-mail: geraint.lewis@sydney.edu.au [Division of Astronomy, University of California, 8979 Math Sciences, Los Angeles, CA 90095-1562 (United States)] [Division of Astronomy, University of California, 8979 Math Sciences, Los Angeles, CA 90095-1562 (United States)

2013-01-20T23:59:59.000Z

290

Nuclear Charge Radii of Be-7,9,10 and the one-neutron halo nucleus Be-11  

E-Print Network [OSTI]

Nuclear charge radii of $^{7,9,10,11}$Be have been determined by high-precision laser spectroscopy. On-line measurements were performed with collinear laser spectroscopy in the $2s_{1/2} \\to 2p_{1/2}$ transition on a beam of Be$^{+}$ ions. Collinear and anticollinear laser beams were used simultaneously and the absolute frequency determination using a frequency comb yielded an accuracy in the isotope-shift measurements of about 1 MHz. Combination with accurate calculations of the mass-dependent isotope shifts yield nuclear charge radii. The charge radius decreases from $^7$Be to $^{10}$Be and then increases for the halo nucleus $^{11}$Be. When comparing our results with predictions of {\\it ab initio} nuclear structure calculations we find good agreement. Additionally, the nuclear magnetic moment of $^7$Be was determined to be $-1.3995(5)\\mu_{\\rm N}$ and that of $^{11}$Be from a previous $\\beta$-NMR measurement was confirmed.

W. Nrtershuser; D. Tiedemann; M. kov; Z. Andjelkovic; K. Blaum; M. L. Bissell; R. Cazan; G. W. F. Drake; Ch. Geppert; M. Kowalska; J. Krmer; A. Krieger; R. Neugart; R. Snchez; F. Schmidt-Kaler; Z. -C. Yan; D. T. Yordanov; C. Zimmermann

2009-02-05T23:59:59.000Z

291

Thorium-rich halo star HD221170: further evidence against the universality of the r-process  

E-Print Network [OSTI]

We report the abundance determination in the atmosphere of the bright halo star HD221170. The spectra were taken with the Terskol Observatory's 2.0-m telescope with a resolution R=45000 and signal-to-noise ratio up to 250 in the wavelength region 3638-10275 \\AA. The adopted atmospheric parameters correspond to an effective temperature \\Tef=4475 K, a surface gravity \\lgg=1.0, a microturbulent velocity \\vmi=1.7 \\kms, and a macroturbulent velocity \\vma=4 \\kms. The abundances of 43 chemical elements were determined with the method of spectrum synthesis. The large overabundances (by 1 dex relative to iron) of elements with Z$>38$ are shown to follow the same pattern as the solar r-abundances. The present HD221170 analysis confirms the non-universality of the r-process, or more exactly the observation that the astrophysical sites hosting the r-process do not always lead to a unique relative abundance distribution for the bulk Ba to Hg elements, the Pb-peak elements, and the actinides.

Alexander Yushchenko; Vera Gopka; Stephane Goriely; Faig Musaev; Angelina Shavrina; Chulhee Kim; Young Woon Kang; Juliana Kuznietsova; Vladimir Yushchenko

2004-09-22T23:59:59.000Z

292

CONSTRAINTS ON THE SHAPE OF THE MILKY WAY DARK MATTER HALO FROM JEANS EQUATIONS APPLIED TO SLOAN DIGITAL SKY SURVEY DATA  

SciTech Connect (OSTI)

We search for evidence of dark matter in the Milky Way by utilizing the stellar number density distribution and kinematics measured by the Sloan Digital Sky Survey (SDSS) to heliocentric distances exceeding {approx}10 kpc. We employ the cylindrically symmetric form of Jeans equations and focus on the morphology of the resulting acceleration maps, rather than the normalization of the total mass as done in previous, mostly local, studies. Jeans equations are first applied to a mock catalog based on a cosmologically derived N-body+SPH simulation, and the known acceleration (gradient of gravitational potential) is successfully recovered. The same simulation is also used to quantify the impact of dark matter on the total acceleration. We use Galfast, a code designed to quantitatively reproduce SDSS measurements and selection effects, to generate a synthetic stellar catalog. We apply Jeans equations to this catalog and produce two-dimensional maps of stellar acceleration. These maps reveal that in a Newtonian framework, the implied gravitational potential cannot be explained by visible matter alone. The acceleration experienced by stars at galactocentric distances of {approx}20 kpc is three times larger than what can be explained by purely visible matter. The application of an analytic method for estimating the dark matter halo axis ratio to SDSS data implies an oblate halo with q{sub DM} = 0.47 {+-} 0.14 within the same distance range. These techniques can be used to map the dark matter halo to much larger distances from the Galactic center using upcoming deep optical surveys, such as LSST.

Loebman, Sarah R.; Ivezic, Zeljko; Quinn, Thomas R.; Governato, Fabio [Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States); Brooks, Alyson M. [Department of Astronomy, University of Wisconsin, 475 North Charter Street, Madison, WI 53706 (United States); Christensen, Charlotte R. [Astronomy Department, University of Arizona, Tucson, AZ (United States); Juric, Mario, E-mail: sloebman@astro.washington.edu [LSST Corporation, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

2012-10-10T23:59:59.000Z

293

Near-Infrared Properties of Moderate-Redshift Galaxy Clusters: Halo Occupation Number, Mass-to-Light Ratios and Omega(M)  

SciTech Connect (OSTI)

Using K-band imaging for 15 of the Canadian Network for Observational Cosmology (CNOC1) clusters we examine the near-infrared properties of moderate-redshift (0.19 < z < 0.55) galaxy clusters. We find that the number of K-band selected cluster galaxies within R{sub 500} (the Halo Occupation Number, HON) is well-correlated with the cluster dynamical mass (M{sub 500}) and X-ray Temperature (T{sub x}); however, the intrinsic scatter in these scaling relations is 37% and 46% respectively. Comparison with clusters in the local universe shows that the HON-M{sub 500} relation does not evolve significantly between z = 0 and z {approx} 0.3. This suggests that if dark matter halos are disrupted or undergo significant tidal-stripping in high-density regions as seen in numerical simulations, the stellar mass within the halos is tightly bound, and not removed during the process. The total K-band cluster light (L{sub 200},K) and K-band selected richness (parameterized by B{sub gc,K}) are also correlated with both the cluster T{sub x} and M{sub 200}. The total (intrinsic) scatter in the L{sub 200,K}-M{sub 200} and B{sub gc,K}-M{sub 200} relations are 43%(31%) and 35%(18%) respectively and indicates that for massive clusters both L{sub 200,K} and B{sub gc,K} can predict M{sub 200} with similar accuracy as T{sub x}, L{sub x} or optical richness (B{sub gc}). Examination of the mass-to-light ratios of the clusters shows that similar to local clusters, the K-band mass-to-light ratio is an increasing function of halo mass. Using the K-band mass-to-light ratios of the clusters, we apply the Oort technique and find {Omega}{sub m,0} = 0.22 {+-} 0.02, which agrees well with recent combined concordance cosmology parameters, but, similar to previous cluster studies, is on the low-density end of preferred values.

Muzzin, Adam; Yee, H.K.C.; /Toronto U., Astron. Dept.; Hall, Patrick B.; /York U., Canada; Lin, Huan; /Fermilab

2007-03-01T23:59:59.000Z

294

Hydro-Gravitational-Dynamics Interpretation of the Tadpole VV29 Merging Galaxy System: Dark-Matter-Halo-Planet Star-Cluster Wakes  

E-Print Network [OSTI]

Hubble Space telescope (HST) images of merging galaxy system VV29 reveal the 0.3 Mpc baryonic-dark-matter (BDM) halo composed of primordial protoglobularstarcluster (PGC) clumps of planets. Star-cluster-wakes trace the merger by formation of stars from the planets. Aligned young globular star clusters (YGCs), star-wakes and dust-trails show the frictional, spiral passage of galaxy fragments VV29cdef in a long tail-like galaxy (VV29b) as the fragments merge on the accretion disk plane of the central spiral galaxy VV29a. The observations confirm the hydro-gravitational-dynamics (HGD) prediction of Gibson 1996 and quasar microlensing inference of Schild 1996 that the dark matter of galaxies is dominated by planets (PFPs) in million-solar-mass clumps. Globular star clusters (YGCs, OGCs, PGCs) preserve the density of the plasma epoch 30,000 years after the big bang when viscous supercluster-fragmentation began. Tadpole images show linear galaxy clusters reflecting turbulent vortex lines of protogalaxy fragmentation at the 0.003 Mpc Kolmogorov-Nomura scale of the plasma before transition to gas. The halo size indicates strong diffusion of PGC primordial-planet-clumps from a cooling protogalaxy as its planets freeze.

Carl H. Gibson

2008-03-29T23:59:59.000Z

295

Chemical Abundances and Dust in the Halo Planetary Nebula K648 in M15: Its Origin and Evolution based on an Analysis of Multiwavelength Data  

E-Print Network [OSTI]

We report an investigation of the extremely metal-poor and C-rich planetary nebula (PN) K648 in the globular cluster M15 using the UV to far-IR data obtained using the Subaru, HST, FUSE, Spitzer, and Herschel. We determined the nebular abundances of ten elements. The enhancement of F ([F/H]=+0.96) is comparable to that of the halo PN BoBn1. The central stellar abundances of seven elements are determined. The stellar C/O ratio is similar to the nebular C/O ratios from recombination line and from collisionally excited line (CEL) within error, and the stellar Ne/O ratio is also close to the nebular CEL Ne/O ratio. We found evidence of carbonaceous dust grains and molecules including Class B 6-9 um and 11.3 um polycyclic aromatic hydrocarbons and the broad 11 um feature. The profiles of these bands are similar to those of the C-rich halo PNe H4-1 and BoBn1. Based on the theoretical model, we determined the physical conditions of the gas and dust and their masses, i.e., 0.048 Msun and 4.95x10^{-7} Msun, respective...

Otsuka, Masaaki; Tajitsu, Akito

2015-01-01T23:59:59.000Z

296

Arrays and Cascades of Fluorescent Liquid-Liquid Waveguides: Broadband Light Sources for  

E-Print Network [OSTI]

Arrays and Cascades of Fluorescent Liquid-Liquid Waveguides: Broadband Light Sources) microchannel waveguides with liquid cores containing fluorescent dyes, excited by incident light from an external halogen bulb. Simultaneous use of multiple fluorophores in a common solution, in a single L2 light

Prentiss, Mara

297

WHAT YOU NEED TO MOVE-IN NECESSITIES TO BRING AT CHECK-IN  

E-Print Network [OSTI]

without headphones Refrigerators more than 4.3 cubic ft. (not permitted in apartments) Water heaters-shutoff feature Immersion heaters Candles/incense/oil lamps Heat lamps/sun lamps Halogen lamps or bulbs Electric blankets Electric heaters Kerosene heaters Picture hangers/nails/double backed stick ups Air

Adali, Tulay

298

22012 Georgia Tech Campus Fire Safety Report ANNUAL STUDENT HOUSING FIRE SAFETY REPORT IN ACCORDANCE WITH THE  

E-Print Network [OSTI]

with the following: · No halogen-touchier lights. The intense heat generated by these bulbs creates a fire hazard fire protection to slow the spread of fire. · Storing bicycles in stairwells or any other location, hazardous materials, etc., is also prohibited. Smoking · Smoking is prohibited in all residence hall areas

299

THE SPATIAL CLUSTERING OF ROSAT ALL-SKY SURVEY AGNs. II. HALO OCCUPATION DISTRIBUTION MODELING OF THE CROSS-CORRELATION FUNCTION  

SciTech Connect (OSTI)

This is the second paper of a series that reports on our investigation of the clustering properties of active galactic nuclei (AGNs) in the ROSAT All-Sky Survey (RASS) through cross-correlation functions (CCFs) with Sloan Digital Sky Survey (SDSS) galaxies. In this paper, we apply the Halo Occupation Distribution (HOD) model to the CCFs between the RASS broad-line AGNs with SDSS luminous red galaxies (LRGs) in the redshift range 0.16 < z < 0.36 that was calculated in Paper I. In our HOD modeling approach, we use the known HOD of LRGs and constrain the HOD of the AGNs by a model fit to the CCF. For the first time, we are able to go beyond quoting merely a 'typical' AGN host halo mass, M{sub h}, and model the full distribution function of AGN host dark matter halos. In addition, we are able to determine the large-scale bias and the mean M{sub h} more accurately. We explore the behavior of three simple HOD models. Our first model (Model A) is a truncated power-law HOD model in which all AGNs are satellites. With this model, we find an upper limit to the slope ({alpha}) of the AGN HOD that is far below unity. The other two models have a central component, which has a step function form, where the HOD is constant above a minimum mass, without (Model B) or with (Model C) an upper mass cutoff, in addition to the truncated power-law satellite component, similar to the HOD that is found for galaxies. In these two models we find that the upper limits on {alpha} are still below unity, with {alpha} {approx}< 0.95 and {alpha} {approx}< 0.84 for Models B and C, respectively. Our analysis suggests that the satellite AGN occupation increases slower than, or may even decrease with, M{sub h}, in contrast to the satellite HODs of luminosity-threshold samples of galaxies, which, in contrast, grow approximately as (N{sub s}) {proportional_to} M{sup {alpha}}{sub h} with {alpha} {approx} 1. These results are consistent with observations that the AGN fraction in groups and clusters decreases with richness.

Miyaji, Takamitsu; Aceves, Hector [Instituto de AstronomIa, Universidad Nacional Autonoma de Mexico, Ensenada, Baja California (Mexico); Krumpe, Mirko; Coil, Alison L., E-mail: miyaji@astrosen.unam.mx [University of California, San Diego, Center for Astrophysics and Space Sciences, 9500 Gilman Drive, La Jolla, CA 92093-0424 (United States)

2011-01-10T23:59:59.000Z

300

GLOBULAR CLUSTERS IN THE OUTER GALACTIC HALO: NEW HUBBLE SPACE TELESCOPE/ADVANCED CAMERA FOR SURVEYS IMAGING OF SIX GLOBULAR CLUSTERS AND THE GALACTIC GLOBULAR CLUSTER AGE-METALLICITY RELATION  

SciTech Connect (OSTI)

Color-magnitude diagrams (CMDs) derived from Hubble Space Telescope (HST) Advanced Camera for Surveys F606W, F814W photometry of six globular clusters (GCs) are presented. The six GCs form two loose groupings in Galactocentric distance (R{sub GC}): IC 4499, NGC 6426, and Ruprecht 106 at {approx}15-20 kpc and NGC 7006, Palomar 15, and Pyxis at {approx}40 kpc. The CMDs allow the ages to be estimated from the main-sequence turnoff in every case. In addition, the age of Palomar 5 (R{sub GC} {approx} 18 kpc) is estimated using archival HST Wide Field Planetary Camera 2 V, I photometry. The age analysis reveals the following: IC 4499, Ruprecht 106, and Pyxis are 1-2 Gyr younger than inner halo GCs with similar metallicities; NGC 7006 and Palomar 5 are marginally younger than their inner halo counterparts; NGC 6426 and Palomar 15, the two most metal-poor GCs in the sample, are coeval with all the other metal-poor GCs within the uncertainties. Combined with our previous efforts, the current sample provides strong evidence that the Galactic GC age-metallicity relation consists of two distinct branches. One suggests a rapid chemical enrichment in the inner Galaxy while the other suggests prolonged GC formation in the outer halo. The latter is consistent with the outer halo GCs forming in dwarf galaxies and later being accreted by the Milky Way.

Dotter, Aaron; Anderson, Jay [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Sarajedini, Ata [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States)

2011-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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

Photodissociation Dynamics of Halogen Oxide Species  

E-Print Network [OSTI]

and photolytic methods. The current work involves the measurement of fundamental physical constants of the XO species. The bond dissociation energy of IO is measured. Vibrational level dependent correlated final state branching ratios of the predissociation...

Dooley, Kristin S.

2010-07-14T23:59:59.000Z

302

HALO GAS AND GALAXY DISK KINEMATICS DERIVED FROM OBSERVATIONS AND LAMBDACDM SIMULATIONS OF Mg II ABSORPTION-SELECTED GALAXIES AT INTERMEDIATE REDSHIFT  

SciTech Connect (OSTI)

We obtained ESI/Keck rotation curves of 10 Mg II absorption-selected galaxies (0.3 <= z <= 1.0) for which we have WFPC-2/HST images and high-resolution HIRES/Keck and UVES/VLT quasar spectra of the Mg II absorption profiles. We perform a kinematic comparison of these galaxies and their associated halo Mg II absorption. For all 10 galaxies, the majority of the absorption velocities lie in the range of the observed galaxy rotation velocities. In 7/10 cases, the absorption velocities reside fully to one side of the galaxy systemic velocity and usually align with one arm of the rotation curve. In all cases, a constant rotating thick-disk model poorly reproduces the full spread of observed Mg II absorption velocities when reasonably realistic parameters are employed. In 2/10 cases, the galaxy kinematics, star formation surface densities, and absorption kinematics have a resemblance to those of high-redshift galaxies showing strong outflows. We find that Mg II absorption velocity spread and optical depth distribution may be dependent on galaxy inclination. To further aid in the spatial-kinematic relationships of the data, we apply quasar absorption-line techniques to a galaxy (v{sub c} = 180 km s{sup -1}) embedded in LAMBDACDM simulations. In the simulations, Mg II absorption selects metal-enriched 'halo' gas out to {approx}100 kpc from the galaxy, tidal streams, filaments, and small satellite galaxies. Within the limitations inherent in the simulations, the majority of the simulated Mg II absorption arises in the filaments and tidal streams and is infalling toward the galaxy with velocities between -200 km s{sup -1} <= v{sub r} <= -180 km s{sup -1}. The Mg II absorption velocity offset distribution (relative to the simulated galaxy) spans {approx}200 km s{sup -1} with the lowest frequency of detecting Mg II at the galaxy systematic velocity.

Kacprzak, Glenn G.; Murphy, Michael T. [Swinburne University of Technology, Victoria 3122 (Australia); Churchill, Christopher W.; Ceverino, Daniel; Klypin, Anatoly [New Mexico State University, Las Cruces, NM 88003 (United States); Steidel, Charles C., E-mail: gkacprzak@astro.swin.edu.a, E-mail: mmurphy@astro.swin.edu.a, E-mail: cwc@nmsu.ed, E-mail: ceverino@nmsu.ed, E-mail: aklypin@nmsu.ed, E-mail: ceverino@phys.huji.ac.i, E-mail: ccs@astro.caltech.ed [California Institute of Technology, Pasadena, CA 91125 (United States)

2010-03-10T23:59:59.000Z

303

Fermi 130 GeV gamma-ray excess and dark matter annihilation in sub-haloes and in the Galactic centre  

SciTech Connect (OSTI)

We analyze publicly available Fermi-LAT high-energy gamma-ray data and confirm the existence of clear spectral feature peaked at E{sub ?} = 130 GeV. Scanning over the Galaxy we identify several disconnected regions where the observed excess originates from. Our best optimized fit is obtained for the central region of Galaxy with a clear peak at 130 GeV with local statistical significance 4.5?. The observed excess is not correlated with Fermi bubbles. We compute the photon spectra induced by dark matter annihilations into two and four standard model particles, the latter via two light intermediate states, and fit the spectra with data. Since our fits indicate sharper and higher signal peak than in the previous works, data favors dark matter direct two-body annihilation channels into photons or other channels giving only line-like spectra. If Einasto halo profile correctly predicts the central cusp of Galaxy, dark matter annihilation cross-section to two photons is of order ten percent of the standard thermal freeze-out cross-section. The large dark matter two-body annihilation cross-section to photons may signal a new resonance that should be searched for at the CERN LHC experiments.

Tempel, Elmo; Hektor, Andi; Raidal, Martti, E-mail: elmo@aai.ee, E-mail: andi.hektor@cern.ch, E-mail: martti.raidal@cern.ch [NICPB, Ravala 10, Tallinn 10143 (Estonia)

2012-09-01T23:59:59.000Z

304

L Prize: The Race for Super Efficient Light Bulbs  

Broader source: Energy.gov [DOE]

This September 23, 2008 webcast provided an overview of the Bright Tomorrow Lighting Prize (L Prize) technology competition. The L Prize calls for super-efficient SSL products to replace two of the...

305

Type of Space Bulb Type #/House Fixture Style Greenhouse #  

E-Print Network [OSTI]

841 360 8 F 32 T8/TL 841 360 9 F 32 T8/TL 841 360 MTPS 216 Ch. 1 F 72 T12 CW/VHO 72 1 Incandescent 60w 72 2 F 72 T12 CW/VHO 72 2 Incandescent 60w 72 5 F 72 T12 CW/VHO 72 5 Incandescent 60w 72 10 F 72 T12 CW/VHO 72 10 Incandescent 60w 72 #12;DR 1009 Ch. 27 F 032/431 4 Seed Chamber Ch. 28 F40T12/ADV 41 6

Pawlowski, Wojtek

306

How Energy-Efficient Light Bulbs Compare with Traditional Incandescents |  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-SeriesFlickr FlickrGuidedCH2MLLC HistoryVeterans | UpdatesHowGetDoes a

307

The History of the Light Bulb | Department of Energy  

Energy Savers [EERE]

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankCombustion |Energy UsageAUDITVehiclesTankless or Demand-Type Water Heaters TanklessDepartment ofTheTheThe

308

Westinghouse and Fuzhou Permitted to Restart Distribution of Light Bulb  

Broader source: Energy.gov (indexed) [DOE]

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment of Energy WhileTanklessLES' URENCO-USAWestern

309

Why Did the LED Light Bulb Cross the Road?  

Office of Energy Efficiency and Renewable Energy (EERE)

Could using humor as a marketing strategy make energy efficiency a bit more digestible? One Illinois grant recipient thinks it could be.

310

New Light Sources for Tomorrow's Lighting Designs  

E-Print Network [OSTI]

, pioneered for headlam~for the automotive industry, has led to the development of halo en capsule lamps for general lighting. The original90-watt family PAR 38 lamps using tungsten halogen capsules produces the sa amount of useful light in the beam as a I... quartz PAR lamps with similar benefi . Each of these tungsten halogen capsule PAR wattages are av ilable in narrow spot, spot, and flood beam patterns. The most recent developments in the PAR halogen psule family include two entirely new lamp designs...

Krailo, D. A.

311

Hot Gas Halos in Galaxies  

SciTech Connect (OSTI)

We use Chandra and XMM-Newton to study how the hot gas content in early-type galaxies varies with environment. We find that the L{sub X}-L{sub K} relationship is steeper for field galaxies than for comparable galaxies in groups and clusters. This suggests that internal processes such as supernovae driven winds or AGN feedback may expel hot gas from low mass field galaxies. Such mechanisms are less effective in groups and clusters where the presence of an intragroup or intracluster medium may confine outflowing material.

Mulchaey, John S. [Carnegie Observatories (United States); Jeltema, Tesla E. [UCO/Lick Observatories (United States)

2010-06-08T23:59:59.000Z

312

Electrical and Optical Enhancement in Internally Nanopatterned Organic Light-Emitting Diodes  

E-Print Network [OSTI]

incandescent bulbs and fluorescent bulbs). Solid-stateindex (CRI) than fluorescent bulbs. Common examples where

Fina, Michael Dane

2012-01-01T23:59:59.000Z

313

Halo and Galaxy Formation Histories from the Millennium Simulation: Public release of a VO-oriented and SQL-queryable database for studying the evolution of galaxies in the LambdaCDM cosmogony  

E-Print Network [OSTI]

The Millennium Run is the largest simulation of the formation of structure within the $\\Lambda$CDM cosmogony so far carried out. It uses $10^{10}$ particles to follow the dark matter distribution in a cubic region 500$h^{-1}$Mpc on a side, and has a spatial resolution of 5 $h^{-1}$kpc. Application of simplified modelling techniques to the stored output of this calculation allows the formation and evolution of the $\\sim 10^7$ galaxies more luminous than the Small Magellanic Cloud to be simulated for a variety of assumptions about the detailed physics involved. As part of the activities of the German Astrophysical Virtual Observatory we have used a relational database to store the detailed assembly histories both of all the haloes and subhaloes resolved by the simulation, and of all the galaxies that form within these structures for two independent models of the galaxy formation physics. We have created web applications that allow users to query these databases remotely using the standard Structured Query Language (SQL). This allows easy access to all properties of the galaxies and halos, as well as to the spatial and temporal relations between them and their environment. Information is output in table format compatible with standard Virtual Observatory tools and protocols. With this announcement we are making these structures fully accessible to all users. Interested scientists can learn SQL, gain familiarity with the database design and test queries on a small, openly accessible version of the Millennium Run (with volume 1/512 that of the full simulation). They can then request accounts to run similar queries on the databases for the full simulations.

G. Lemson; the Virgo Consortium

2006-08-03T23:59:59.000Z

314

Theoretical studies of the dynamics of chemical reactions  

SciTech Connect (OSTI)

Recent research effort has focussed on several reactions pertinent to combustion. The formation of the formyl radical from atomic hydrogen and carbon monoxide, recombination of alkyl radicals and halo-alkyl radicals with halogen atoms, and the thermal dissociation of hydrogen cyanide and acetylene have been studied by modeling. In addition, the inelastic collisions of NCO with helium have been investigated.

Wagner, A.F. [Argonne National Laboratory, IL (United States)

1993-12-01T23:59:59.000Z

315

Origin of Halogens and Nitrogen in Enstatite Chondrites  

E-Print Network [OSTI]

A. Bischoff, J. Zipfel, Mineralogy of the Neuschwanstein (minmag.1997.061.408.09 A.E. Rubin, Mineralogy of meteoriteBuseck, E.F. Holdsworth, Mineralogy and petrology of the

Rubin, Alan E.; Choi, Byeon-Gak

2009-01-01T23:59:59.000Z

316

Synthesis and Characterization of Halogen-Free Antiflammable Polyphosphonates Containing  

E-Print Network [OSTI]

flammability. Polyethylene and polypropylene, for example, possess heat of combustion properties on par exhibited low combustion heat release rate and total heat of combustion, which we believe arises from

317

Toward the photo-induced reductive elimination of halogens  

E-Print Network [OSTI]

Light-driven energy conversion schemes have been proposed as alternative energy to fossil fuels. The target fuel of these schemes is hydrogen. For photocatalytic hydrogen production to be feasible, it must be performed on ...

Manke, David

2005-01-01T23:59:59.000Z

318

Transient x-ray absorption spectroscopy of hydrated halogen atom  

E-Print Network [OSTI]

Time-resolved x-ray absorption spectroscopy has been used to observe the transient species generated by one-photon detachment of an electron from aqueous bromide. The K-edge spectrum of the short-lived Br(0) atom exhibits a resonant 1s-4p transition...

Elles, Christopher G.; Shkrob, Ilya A.; Crowell, Robert A.; Arms, Dohn A.; Landahl, Eric C.

2008-02-11T23:59:59.000Z

319

Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy  

DOE Patents [OSTI]

A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na.sub.4 B.sub.12 I.sub.11 SSB.sub.12 I.sub.11, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy.

Miura, Michiko (Hampton Bays, NY); Slatkin, Daniel N. (Southold, NY)

1997-03-18T23:59:59.000Z

320

Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy  

DOE Patents [OSTI]

A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na{sub 4}B{sub 12}I{sub 11}SSB{sub 12}I{sub 11}, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy. 1 fig.

Miura, M.; Slatkin, D.N.

1997-03-18T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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

Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy  

DOE Patents [OSTI]

A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na.sub.4 B.sub.12 I.sub.11 SSB.sub.12 I.sub.11, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy.

Miura, Michiko (Hampton Bays, NY); Slatkin, Daniel N. (Southold, NY)

1995-10-03T23:59:59.000Z

322

Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy  

DOE Patents [OSTI]

A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na{sub 4}B{sub 12}I{sub 11}SSB{sub 12}I{sub 11}, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy. 1 fig.

Miura, M.; Slatkin, D.N.

1997-08-05T23:59:59.000Z

323

Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy  

DOE Patents [OSTI]

A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized. by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na.sub.4 B.sub.12 I.sub.11 SSB.sub.12 I.sub.11, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy.

Miura, Michiko (Hampton Bays, NY); Slatkin, Daniel N. (Southold, NY)

1997-08-05T23:59:59.000Z

324

Halogen eAppraisal - Performance Appraisals | The Ames Laboratory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-SeriesFlickr FlickrGuided Self-Assembly of GoldHAWCHIGSSite

325

Investigations into the Nature of Halogen Bonding Including Symmetry  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFunInfrared LandResponses toInvestigatingAdapted Perturbation Theory Analyses. |

326

Barber, Whitesides I Redut'tiLleClearage of Carhon-Halogen Bonds ReductiveCleavageof Carbon-HalogenBondsby  

E-Print Network [OSTI]

halogenatom abstractionfrom thc alkyl halideby a nragnesiumatom (eq 2). c R -X * Ms, [R-X]-. sfcr + Me(l)- R

Prentiss, Mara

327

Halo and Galaxy Formation Histories from the Millennium Simulation: Public release of a VO-oriented and SQL-queryable database for studying the evolution of galaxies in the LambdaCDM cosmogony  

E-Print Network [OSTI]

The Millennium Run is the largest simulation of the formation of structure within the $\\Lambda$CDM cosmogony so far carried out. It uses $10^{10}$ particles to follow the dark matter distribution in a cubic region 500$h^{-1}$Mpc on a side, and has a spatial resolution of 5 $h^{-1}$kpc. Application of simplified modelling techniques to the stored output of this calculation allows the formation and evolution of the $\\sim 10^7$ galaxies more luminous than the Small Magellanic Cloud to be simulated for a variety of assumptions about the detailed physics involved. As part of the activities of the German Astrophysical Virtual Observatory we have used a relational database to store the detailed assembly histories both of all the haloes and subhaloes resolved by the simulation, and of all the galaxies that form within these structures for two independent models of the galaxy formation physics. We have created web applications that allow users to query these databases remotely using the standard Structured Query Langu...

Lemson, G

2006-01-01T23:59:59.000Z

328

Bringing climate change down to earth : science and participation in Canadian and Australian climate change campaigns  

E-Print Network [OSTI]

bulbs with compact fluorescent bulbs. This led to a fair bitsuch as compact fluorescent bulbs, low-flow showerheads, andtechnologies: compact fluorescent light bulbs, energy saving

Padolsky, Miriam Elana

2006-01-01T23:59:59.000Z

329

Secret Ninja Testing with HALO Software Engineering  

E-Print Network [OSTI]

· Testing can be tedious - there is low student engagement and interest in testing 2 #12;Gamification 3 · We propose a social approach to expose students to software testing using gamification · Our gamification gamification platform · Eclipse plugin · Maps various SE features to game world - Doesn't have to follow

Kaiser, Gail E.

330

Saturn's moon rhea sports a dusty halo  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas ConchasPassiveSubmitted for USMaterialstheterahertz sourcesSatellite stories

331

Hanford Site annual dangerous waste report, calendar year 1995  

SciTech Connect (OSTI)

This report is a compilation of data on the disposition of hazardous wastes generated on the Hanford Reservation. This information is on EPA requirement every two years. Wastes include: tank simulant waste; alkaline batteries; lead-based paints; organic solvents; light bulbs containing lead and/or mercury; monitoring well drilling wastes; soils contaminated with trace metals, halogenated organics, or other pollutants; Ni-Cd batteries; pesticides; waste oils and greases; wastes from the cleanup of fuel/gasoline spills; filters; metals; and other.

NONE

1995-12-31T23:59:59.000Z

332

E-Print Network 3.0 - adult olfactory bulb Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

et... of these randomly distributed neurons project to spatially conserved ... Source: Vogt, Richard G. - Department of Biological Sciences, University of South Carolina...

333

E-Print Network 3.0 - alters olfactory bulb Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

... Source: Betz, William J. - Department of Physiology and Biophysics, University of Colorado Health Sciences Center Collection: Biology and Medicine 8 The Journal of...

334

What Light Bulbs Do You Use in Your Home? | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Blackout? LED lights are six to seven times more energy efficient than conventional incandescent lights, cut energy use by more than 80 percent and can last more than 25 times...

335

DOE Requires Westinghouse to Cease Sales of Two Light Bulb Models...  

Broader source: Energy.gov (indexed) [DOE]

and Fuzhou Sunlight Lighting Electrical Appliance Company to allow the companies to resume sales of an incandescent reflector lamp basic model 50PAR30F (Westinghouse product...

336

A Winning Light Bulb With the Potential to Save the Nation Billions |  

Energy Savers [EERE]

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankCombustion |Energy UsageAUDITVehiclesTankless orA BRIEF HISTORY OF THE DEPARTMENT OF

337

Consumer Light Bulb Changes: Briefing and Resources for Media and Retailers  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-Up fromDepartmentTieCelebrate Earth Codestheatfor Optimized91PowerCapacitorConsumer|

338

Which Bulb Is Right for You? (High-Resolution EPS Billboard) | Department  

Broader source: Energy.gov (indexed) [DOE]

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment of Energy WhileTanklessLES'NeighborhoodThis workshop

339

Which Bulb Is Right for You? (High-Resolution JPG Billboard) | Department  

Broader source: Energy.gov (indexed) [DOE]

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment of Energy WhileTanklessLES'NeighborhoodThis workshopof Energy

340

Which Bulb Is Right for You? (Low-Resolution JPG Billboard) | Department of  

Broader source: Energy.gov (indexed) [DOE]

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment of Energy WhileTanklessLES'NeighborhoodThis workshopof

Note: This page contains sample records for the topic "halogen bulbs halo" 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

Westinghouse Pays $50,000 Civil Penalty to Resolve Light Bulb Efficiency  

Office of Environmental Management (EM)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "of EnergyEnergyENERGYWomen Owned SmallOf TheViolations | Department of Energy Westinghouse Pays $50,000

342

DOE Requires Westinghouse to Cease Sales of Two Light Bulb Models and  

Broader source: Energy.gov (indexed) [DOE]

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarly Career Scientists'Montana. DOCUMENTSof Energy DOEDOEAVAILABLEDepartment ofHeldViolating

343

DOE Withdraws the Energy Star Label from 34 Compact Fluorescent Light Bulbs  

Broader source: Energy.gov (indexed) [DOE]

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarly Career Scientists'Montana. DOCUMENTSof EnergyAlliance |Department ofShowerheads | Department|

344

Buying the Perfect Energy-Efficient Light Bulb in 5 Easy Steps | Department  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:Year in Review: Top FiveDepartment of Energy BuildingsBuried andSoft CostsBuy AmericanBuying

345

Development of Diagnostic Rules for a Dry Bulb Economizer Mixed Air Loop  

E-Print Network [OSTI]

Diagnostics of heating, ventilating, and air-conditioning (HVAC) systems is becoming increasingly important because of the rising cost of operation and maintenance of HVAC systems. At the same time, computer costs are tumbling allowing their use...

Underwood, D.

1990-01-01T23:59:59.000Z

346

ANALYSIS OF THE CALIFORNIA ENERGY INDUSTRY  

E-Print Network [OSTI]

firms currently producing fluorescent bulbs. Phantom tubea per- centage of fluorescent light bulbs from the installed

Authors, Various

2010-01-01T23:59:59.000Z

347

Sleep, mood, and circadian responses to bright green light during sleep  

E-Print Network [OSTI]

white light from fluorescent bulbs, as point sources mightthan incandescent bulbs. Also, fluorescent light is easier

Grandner, Michael Andrew

2007-01-01T23:59:59.000Z

348

Protocol for Maximizing Energy Savings and Indoor Environmental Quality Improvements when Retrofitting Apartments  

E-Print Network [OSTI]

bulbswithcompactfluorescentbulbs. Inaddition,thea?lightbulbswith fluorescentlightbulbsthatuselesslight bulbs with compact fluorescentlights Replace

Noris, Federico

2014-01-01T23:59:59.000Z

349

Demonstration Assessment of Light Emitting Diode (LED) Residential Downlights and Undercabinet Lights in the Lane County Tour of Homes, Eugene, Oregon  

SciTech Connect (OSTI)

In August 2008 the Pacific Northwest National Laboratory (PNNL) conducted a light emitting diode (LED) residential lighting demonstration project for the U.S. Department of Energy (DOE), Office of Building Technologies, as part of DOEs Solid State Lighting (SSL) Technology Demonstration Gateway Program. Two lighting technologies, an LED replacement for downlight lamps (bulbs) and an LED undercabinet lighting fixture, were tested in the demonstration which was conducted in two homes built for the 2008 Tour of Homes in Eugene, Oregon. The homes were built by the Lane County Home Builders Association (HBA), and Future B Homes. The Energy Trust of Oregon (ETO) also participated in the demonstration project. The LED downlight product, the LR6, made by Cree LED Lighting Solutions acts as a screw-in replacement for incandescent and halogen bulbs in recessed can downlights. The second product tested is Phillips/Color Kinetics eW Profile Powercore undercabinet fixture designed to mount under kitchen cabinets to illuminate the countertop and backsplash surfaces. Quantitative and qualitative measurements of light performance and electrical power usage were taken at each site before and after initially installed halogen and incandescent lamps were replaced with the LED products. Energy savings and simple paybacks were also calculated and builders who toured the homes were surveyed for their responses to the LED products. The LED downlight product drew 12 Watts of power, cutting energy use by 82% compared to the 65W incandescent lamp and by 84% compared to the 75W halogen lamp. The LED undercabinet fixture drew 10 watts, cutting energy use by 83% to 90% compared to the halogen product, which was tested at two power settings: a low power 60W setting and a high power 105W setting. The LED downlight consistently provided more light than the halogen and incandescent lamps in horizontal measurements at counter height and floor level. It also outperformed in vertical illuminance measurements taken on the walls, indicating better lateral dispersion of the light. The undercabinet fixtures light output was midway between the low and high power halogen undercabinet fixture light outputs (35.8 foot candle versus 13.4 fc and 53.4 fc) but it produced a more uniform light (max/min ratio of 7.0 versus 10.8). The color correlated temperature (CCT, the blue or yellowness) of the LED light correlated well with the halogen and incandescent lights (2675 K vs 2700 K). The color rendering of the LED downlight also correlated well at 92 CRI compared to 100 CRI for the halogen and incandescent lamps. The LED undercabinet fixture had measures of 2880 K CCT and 71 CRI compared to the 2700 K and 100 CRI scores for the halogen undercabinet fixture. Builders who toured the homes were surveyed; they gave the LED downlight high marks for brightness, said the undercabinet improved shadows and glare and said both products improved overall visibility, home appearance, and home value. Paybacks on the LED downlight ranged from 7.6 years (assuming electricity cost of 11 c/kWh) to 13.5 years (at 5C/kWh). Paybacks on the LED undercabinet fixture in a new home ranged from 4.4 years (11c/kWh electricity) to 7.6 years (5c/kWh) based on product costs of $95 per LED downlight and $140 per LED undercabinet fixture at 3 hrs per day of usage for the downlight and 2 hrs per day for the undercabinet lighting.

Ton, My K.; Richman, Eric E.; Gilbride, Theresa L.

2008-11-10T23:59:59.000Z

350

Remedial extraction and catalytic hydrodehalogenation for treatment of soils contaminated by halogenated hydrophobic organic compounds  

E-Print Network [OSTI]

for the extraction of 1,2,4,5-tetrachlorobenzne (TeCB) or pentachlorophenol (PCP) from contaminated soil. Palladium-catalyzed hydrodehalogenation (HDH) was applied for destroying TeCB or PCP in mixtures of water and ethanol in a batch mode. The experimental results...

Wee, Hun Young

2009-05-15T23:59:59.000Z

351

Supramolecular self-assembled network formation containing NBr halogen bonds in physisorbed overlayers  

E-Print Network [OSTI]

was Papyex, an exfoliated recompressed graphite foil from Le Carbon. Papyex is a compressed powder of graphite crystallites, which have had a preferred orientation imparted to them from the manufacturing process. This preferred orientation was used... at Diamond Light Source, UK36. The X-ray wavelength used was 1.033787 with a detector zero angle offset of 0.00803 for the co-layer, and 1.054700 with a detector offset of 0.05899 for the pure DBTFB layer as determined by Rietveld refinement of a...

Brewer, Adam Y.; Sacchi, Marco; Parker, Julia E.; Truscott, Chris L.; Jenkins, Steve; Clarke, Stuart M.

2014-08-05T23:59:59.000Z

352

COLLISIONS OF HALOGEN (2P) AND RARE GAS (1S) ATOMS  

E-Print Network [OSTI]

involving 2p excited states of alkali atoms, with groundstate rare gas atoms (RG), though other systems have been2p ) AND RARE GAS (IS) ATOMS Christopher Hank Becker (Ph. D.

Becker, Christopher Hank

2011-01-01T23:59:59.000Z

353

Reactive Halogens in the Marine Boundary Layer (RHaMBLe): the tropical North Atlantic experiments  

E-Print Network [OSTI]

105, 2419124204, 2000. Allan, B. J. , Plane J. M. C. , andlayer, Geophys. Res. Lett. , Allan, J. D. , Topping, D. O. ,1,2 , G. McFiggans 3 , J. D. Allan 3,4 , A. R. Baker 5 , S.

2010-01-01T23:59:59.000Z

354

Photoelectron spectroscopy of the halogen oxide anions FO-, CIO-, BrO-, IO-, OCIO-, and OIO-  

E-Print Network [OSTI]

of Colorado and National Institute of Standards and Technology, and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440 (Received 29 January 1992; accepted 28 February 1992, by Dotan et al." Vogt et a1.12measured the energy depend- ence of the ClO- product channel in the reaction

Lineberger, W. Carl

355

Supplementary material for ACP manuscripts "A chemical probe technique for the determination of reactive halogen  

E-Print Network [OSTI]

and the sample was saturated with sodium sulfate and extracted twice with 5.0 mL of ethyl acetate. The extracts-linear inverse plots and the influence of allyl alcohol in bromide solutions The kinetic derivation that describes the non-linear inverse plots (e.g., Figure 2 in Part 1), and the effect that allyl alcohol has

Meskhidze, Nicholas

356

Analysis and Characterization of Halogenated Transformation Products of Pharmaceuticals and Personal Care Products in Wastewater Effluent  

E-Print Network [OSTI]

from a Millipore water purification system (Billerica, MA).from a Millipore water purification system (Billerica, MA).

Bulloch, Daryl Neil

2013-01-01T23:59:59.000Z

357

Analysis and Characterization of Halogenated Transformation Products of Pharmaceuticals and Personal Care Products in Wastewater Effluent  

E-Print Network [OSTI]

techniques (e.g. reverse osmosis and nanofiltration) as welltechniques such as reverse osmosis and/or nanofiltration.

Bulloch, Daryl Neil

2013-01-01T23:59:59.000Z

358

Investigating the biosynthesis of halogenated meroterpenoid natural products from marine actinomycetes  

E-Print Network [OSTI]

following conditions: 40 ml of 20% acetonitrile:water, 60ml of 40% acetonitrile:water, 60ml of 60% acetonitrile:water, 60 ml of 80% acetonitrile:

Winter, Jaclyn Marie

2010-01-01T23:59:59.000Z

359

Investigating the Biosynthesis of Halogenated Meroterpenoid Natural Products from Marine Actinomycetes  

E-Print Network [OSTI]

following conditions: 40 ml of 20% acetonitrile:water, 60ml of 40% acetonitrile:water, 60ml of 60% acetonitrile:water, 60 ml of 80% acetonitrile:

Winter, Jaclyn Marie

2010-01-01T23:59:59.000Z

360

The Halogenation of Oils with Special Attention to the Method of Wijs  

E-Print Network [OSTI]

by him in the following manner: ! In the preparation of the solutions. HgCl 8 + 41 = Hg I a + 2 IC1 IC1 + H 20 5 HC1 + HIO 2. On keeping the solution. 2 HIO + C 2H 60 = 21 + 2H 20 + C 2H 40 3. In the absorption (oleic acid). C0 2H.Ci 7H a a + HIO... at once a substance capable of liberating iodine from potassium iodide. He expressed the chemical change by the following equation: HgCl + I 2 - Hg C1I + IC1 Ephraim regarded the fact that he could ob tain results identical to those of Hubl, by using...

Rhodes, Edmund Oliver

1913-05-15T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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.


361

Treatment and prevention systems for acid mine drainage and halogenated contaminants  

DOE Patents [OSTI]

Embodiments include treatments for acid mine drainage generation sources (10 perhaps by injection of at least one substrate (11) and biologically constructing a protective biofilm (13) on acid mine drainage generation source materials (14). Further embodiments include treatments for degradation of contaminated water environments (17) with substrates such as returned milk and the like.

Jin, Song (Fort Collins, CO); Fallgren, Paul H. (Laramie, WY); Morris, Jeffrey M. (Laramie, WY)

2012-01-31T23:59:59.000Z

362

Halogen-elimination photochemistry and oxygen-activation chemistry of late transition-metal complexes  

E-Print Network [OSTI]

Multi-electron reaction chemistry, from both ground- and excited-state species, is at the heart of many topics in renewable energy and catalysis. In this thesis, two classes of reactions central to the themes of energy ...

Teets, Thomas S. (Thomas Sebastian)

2012-01-01T23:59:59.000Z

363

Halogen-Based Plasma Etching of Novel Field-Effect Transistor Gate Materials  

E-Print Network [OSTI]

Surface Interactions in Fluorocarbon Etching of Silicon2706. Xu, S.L. , et al. , Fluorocarbon polymer formation,

Kiehlbaugh, Kasi Michelle

2009-01-01T23:59:59.000Z

364

Gold and gold-graphene used as cathodic interfaces for scission of carbon-halogen bonds.  

E-Print Network [OSTI]

. Application to the building of anthraquinone-Au electrodes. Jacques Simonet a * and Viatcheslav Jouikov b a as cathode material. This first work points out the immobilization of anthraquinone (AQ) in organic polar.12.024 #12;2 Graphical Abstract Key Words: Graphene; 2-Bromomethylanthraquinone; Anthraquinone electrodes

Paris-Sud XI, Université de

365

Analysis and Characterization of Halogenated Transformation Products of Pharmaceuticals and Personal Care Products in Wastewater Effluent  

E-Print Network [OSTI]

and biological treatments for wastewater decontamination- Atreatment involves biological degradation of organic wastewaterBiological effects of transformation products. The extent of attenuation of PPCPs through wastewater treatment

Bulloch, Daryl Neil

2013-01-01T23:59:59.000Z

366

Essays in Public Economics and Development  

E-Print Network [OSTI]

adopt compact fluorescent light bulbs (CFLs), and possibleof compact fluorescent light bulbs (CFLs) from PROCEL, andAdoption of compact fluorescent light bulbs In the PROCEL

Gerard, Francois

2013-01-01T23:59:59.000Z

367

Max Tech and Beyond: Maximizing Appliance and Equipment Efficiency by Design  

E-Print Network [OSTI]

for the motor (30 W). Fluorescent bulbs gain 75% efficiencyreplaced with compact fluorescent bulbs, with LEDs being aCommission compact fluorescent light bulb cubic feet per

Desroches, Louis-Benoit

2012-01-01T23:59:59.000Z

368

A world of cruelty in Titus Andronicus /  

E-Print Network [OSTI]

were the flickering fluorescent bulbs, a single scream andmade mostly for the fluorescent bulbs. Kristin Hayes, thecold light of a fluorescent bulb exposes and illuminates

Brody, Joshua Kahan

2013-01-01T23:59:59.000Z

369

DSM Electricity Savings Potential in the Buildings Sector in APP Countries  

E-Print Network [OSTI]

150 million compact fluorescent light bulbs in 2010. (ChinaCleaners Incandescent Bulbs Fluorescent Lamps Ballasts forincandescent bulbs with compact fluorescent lamps. Consumers

McNeil, MIchael

2011-01-01T23:59:59.000Z

370

Delivering Energy Efficiency to Middle Income Single Family Households  

E-Print Network [OSTI]

system CFL Compact Fluorescent Light Bulb IAQ Indoor Airdiscount compact fluorescent light bulbs (CFLs) or providediscount compact fluorescent light bulbs (CFLs) or provide

Zimring, Mark

2012-01-01T23:59:59.000Z

371

Zinc Oxide and Nitride Nanowire Based Light Emitting Diodes  

E-Print Network [OSTI]

of incandescent light bulb, fluorescent lamp, and blue lightof incandescent light bulb, fluorescent lamp, and blue lightincandescent bulb and is on the same order as fluorescent

Lai, Elaine Michelle

2009-01-01T23:59:59.000Z

372

Behavioral Perspectives on Home Energy Audits: The Role of Auditors, Labels, Reports, and Audit Tools on Homeowner Decision Making  

E-Print Network [OSTI]

and dishwasher, all fluorescent bulbs Changed about on. I use more fluorescent bulbs now. Increased Furnace Installed fluorescent light bulbs Insulate

Ingle, Aaron

2013-01-01T23:59:59.000Z

373

PowerChoice Residential Customer Response to TOU Rates  

E-Print Network [OSTI]

or pin based compact fluorescent bulbs. If asked, count both15. How many compact fluorescent bulbs have you installedregular fixtures with fluorescent bulbs? Installing timers

Peters, Jane S.

2010-01-01T23:59:59.000Z

374

Estimate of Technical Potential for Minimum Efficiency Performance Standards in 13 Major World Economies  

E-Print Network [OSTI]

for typical wattage of incandescent bulbs and hours of usagefor which we assume that incandescent bulbs gradually getsimilar to that of incandescent or fluorescent bulbs. These

Letschert, Virginie

2013-01-01T23:59:59.000Z

375

Impact of Large Scale Energy Efficiency Programs On Consumer Tariffs and Utility Finances in India  

E-Print Network [OSTI]

consumers to replace incandescent bulbs with CFLs. Weprograms (for example, incandescent bulbs) and j indicatesend-use (for example, incandescent bulbs) in 2011 and, T c

Abhyankar, Nikit

2011-01-01T23:59:59.000Z

376

Energy Data Sourcebook for the U.S. Residential Sector  

E-Print Network [OSTI]

device. For instance, an incandescent bulb used one hour persockets. We create incandescent bulb UECs by both hours ofand lifetimes for standard incandescent bulbs and their more

Wenzel, T.P.

2010-01-01T23:59:59.000Z

377

Chemical Dependencies of Learning in the Rabbit Olfactory Bulb: Acquisition of the Transient Spatial Pattern Chance Depends on Norepinephrine  

E-Print Network [OSTI]

electrode were placed in the orhit..I'he orbital cavity and dorsal openings were tilled \\\\ ith sterile agar-

Gray, Charles M; Freeman, Walter J III; Skinner, James E

1986-01-01T23:59:59.000Z

378

Funding Sustainable Initiatives: Should Williams Implement a Revolving Loan Fund?  

E-Print Network [OSTI]

to replace its incandescent light bulbs with more efficient compact fluorescent (CFL) light bulbs. These light bulbs use 2/3 less energy than #12;Terra 4 standard incandescent bulbs, but they are more

Aalberts, Daniel P.

379

E-Print Network 3.0 - astatine 212 Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Collection: Biology and Medicine ; Engineering 36 Zevenhoven & Kilpinen Halogens, dioxinsfurans 17.6.2001 7-1 Chapter 7 Halogens, Summary: .1 Introduction The halogens are...

380

E-Print Network 3.0 - astatine chlorides Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

and Medicine ; Environmental Sciences and Ecology 27 Zevenhoven & Kilpinen Halogens, dioxinsfurans 17.6.2001 7-1 Chapter 7 Halogens, Summary: .1 Introduction The halogens are...

Note: This page contains sample records for the topic "halogen bulbs halo" 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

E-Print Network 3.0 - astatine compounds Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

University of Waterloo Collection: Chemistry 34 Zevenhoven & Kilpinen Halogens, dioxinsfurans 17.6.2001 7-1 Chapter 7 Halogens, Summary: .1 Introduction The halogens are...

382

E-Print Network 3.0 - astatine 215 Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Physics Group Collection: Materials Science 35 Zevenhoven & Kilpinen Halogens, dioxinsfurans 17.6.2001 7-1 Chapter 7 Halogens, Summary: .1 Introduction The halogens are...

383

Radius of B-8 halo from the asymptotic normalization coefficient  

E-Print Network [OSTI]

W !& 5 ( lB ,mlB jBm jB ^JAM A jBm jBuJBM B& 3^JpM plBmlBu jbm jB&i lBY lBmlB~r? !IAplB jB B ~r !. ~1! A is the antisymmetrization operator, w is a bound-state IAplB jB B ~r !?CAplB jB B WhB ,lB11/2~2kBr ! r . ~3! Here CAplB jB B... overlap integrals I(r). The multipole expansion is carried out over lB , jB values allowed by angular momentum and parity conservation for the virtual process B?A1p . The overlap integral is not an eigenfunction of the total Hamiltonian, and hence...

Carstoiu, F.; Trache, L.; Gagliardi, Carl A.; Tribble, Robert E.; Mukhamedzhanov, AM.

2001-01-01T23:59:59.000Z

384

Nuclear induced breakup of halo nuclei H. Esbensen  

E-Print Network [OSTI]

energies. The description of breakup reactions at low beam energies is much more difficult because one, which is the conventional method used to describe low-energy, heavy-ion reactions of ordinary nuclei treatment is much larger than the exact result. This trend is also indicated at low energy by comparing

Bertsch George F.

385

FINAL PROJECT REPORT LOAD MODELING TRANSMISSION RESEARCH  

E-Print Network [OSTI]

to be the compact fluorescent bulbs (CFBs) that the engineerbulbs with compact fluorescent bulbs (CFBs) continues to

Lesieutre, Bernard

2013-01-01T23:59:59.000Z

386

Catalog of DC Appliances and Power Systems  

E-Print Network [OSTI]

loss for the compact fluorescent bulb replacement. For mosta light bulb or tube, a compact fluorescent lamp typically

Garbesi, Karina

2012-01-01T23:59:59.000Z

387

Energy Consumption, Efficiency, Conservation, and Greenhouse Gas Mitigation in Japan's Building Sector  

E-Print Network [OSTI]

and a washroom with bulb-type fluorescent lamps, (5) closingusing incandescent bulbs to fluorescent lamps. This switch

2006-01-01T23:59:59.000Z

388

Effects of trace metals on diatom export products from the euphotic zone and significance for biogeochemical cycles  

E-Print Network [OSTI]

was provided by 3 cool white fluorescent bulbs and oneplant growth fluorescent bulb at ?4300 lux. All cultures

Richter, Daniel J.

389

Laboratory Ventilation SafetyLaboratory Ventilation Safety J. Scott WardJ. Scott Ward  

E-Print Network [OSTI]

the incandescent light bulb in 1879.incandescent light bulb in 1879. #12;First Labconco Hood 1936First Labconco

Farritor, Shane

390

Method of Dehalogenation using Diamonds  

SciTech Connect (OSTI)

A method for preparing olefins and halogenated olefins is provided comprising contacting halogenated compounds with diamonds for a sufficient time and at a sufficient temperature to convert the halogenated compounds to olefins and halogenated olefins via elimination reactions.

Farcasiu, Malvina; Kaufman, Phillip B.; Ladner, Edward P.; Anderson, Richard R.

1999-02-26T23:59:59.000Z

391

Kinetic Modeling of Halogen-Based Plasma Etching of Complex Oxide Films and its Application to Predictive Feature Profile Simulation  

E-Print Network [OSTI]

Fit. 2) Press Normal fit several time until the resultfinal.mat (Cauchy fit) 2. Fit 1) Press Window and select thickness. Check the Fit box, and press OK. 2. For

Marchack, Nathan

2012-01-01T23:59:59.000Z

392

Body burdens of brominated flame retardants and other persistent organo-halogenated compounds and their descriptors in US girls  

SciTech Connect (OSTI)

Background: Levels of brominated flame retardants are increasing in US populations, yet little data are available on body burdens of these and other persistent hormonally active agents (HAAs) in school-aged children. Exposures to such chemicals may affect a number of health outcomes related to development and reproductive function. Objective: Determine the distribution of biomarkers of polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and organo-chlorinated pesticides (OCPs), such as DDT/DDE, in children, and their variation by key descriptor variables. Methods: Ethnically diverse cohorts of girls 6-8 y old at baseline are being followed for growth and pubertal development in a multi-site, longitudinal study. Nearly 600 serum samples from the California and Ohio sites were analyzed for lipids, 35 PCB congeners, 11 PBDE congeners, and 9 OCPs. The biomarker distributions were examined and geometric means compared for selected analytes across categories of age, race, site, body mass index (BMI), parental education, maternal age at delivery, and breast feeding in adjusted models. Results: Six PBDE congeners were detected among greater than 70% of samples, with BDE-47 having the highest concentration (median 42.2, range 4.9-855 ng/g lipid). Girls in California had adjusted geometric mean (GM) PBDE levels significantly higher than girls in Ohio. Furthermore, Blacks had significantly higher adjusted GMs of all six PBDE congeners than Whites, and Hispanics had intermediate values. GMs tended to be lower among more obese girls, while other variables were not strongly associated. In contrast, GMs of the six PCB congeners most frequently detected were significantly lower among Blacks and Hispanics than Whites. PCBs and the three pesticides most frequently detected were also consistently lower among girls with high BMI, who were not breast-fed, whose mothers were younger, or whose care-givers (usually parents) were less educated. Girls in California had higher GMs than in Ohio for the pesticides and most PCB congeners, but the opposite for CB-99 and -118. Conclusions: Several of these potential HAAs were detected in nearly all of these young girls, some at relatively high levels, with variation by geographic location and other demographic factors that may reflect exposure pathways. The higher PBDE levels in California likely reflect differences in fire regulation and safety codes, with potential policy implications.

Windham, Gayle C., E-mail: gayle.windham@cdph.ca.gov [CA Department of Public Health, DEODC, 850 Marina Bay Pkwy, Bldg. P, Richmond, CA 94804 (United States); Pinney, Susan M. [University of Cincinnati College of Medicine, Cincinnati, OH 45267 (United States)] [University of Cincinnati College of Medicine, Cincinnati, OH 45267 (United States); Sjodin, Andreas [Centers for Disease Control and Prevention, Atlanta, GA 30341 (United States)] [Centers for Disease Control and Prevention, Atlanta, GA 30341 (United States); Lum, Raymond [Impact Assessment Inc., San Diego, CA (United States)] [Impact Assessment Inc., San Diego, CA (United States); Jones, Richard S.; Needham, Larry L. [Centers for Disease Control and Prevention, Atlanta, GA 30341 (United States)] [Centers for Disease Control and Prevention, Atlanta, GA 30341 (United States); Biro, Frank M. [University of Cincinnati College of Medicine, Cincinnati, OH 45267 (United States)] [University of Cincinnati College of Medicine, Cincinnati, OH 45267 (United States); Hiatt, Robert A. [University of California Medical School, San Francisco, CA (United States)] [University of California Medical School, San Francisco, CA (United States); Kushi, Lawrence H. [Kaiser Permanente Northern California, Oakland, CA 94612 (United States)] [Kaiser Permanente Northern California, Oakland, CA 94612 (United States)

2010-04-15T23:59:59.000Z

393

Kinetic model for predicting the concentrations of active halogens species in chlorinated saline cooling waters. Final report  

SciTech Connect (OSTI)

A kinetic model has been developed for describing the speciation of chlorine-produced oxidants in seawater as a function of time. The model is applicable under a broad variety of conditions, including all pH range, salinities, temperatures, ammonia concentrations, organic amine concentrations, and chlorine doses likely to be encountered during power plant cooling water chlorination. However, the effects of sunlight are not considered. The model can also be applied to freshwater and recirculating water systems with cooling towers. The results of the model agree with expectation, however, complete verification is not feasible at the present because analytical methods for some of the predicted species are lacking.

Haag, W.R.; Lietzke, M.H.

1981-08-01T23:59:59.000Z

394

Kinetic Modeling of Halogen-Based Plasma Etching of Complex Oxide Films and its Application to Predictive Feature Profile Simulation  

E-Print Network [OSTI]

Plasma Diagnostics ..O 0.66 films. 2.4 Plasma Diagnostics 2.4.1 Langmuir Probeis one of the first plasma diagnostic devices. By performing

Marchack, Nathan

2012-01-01T23:59:59.000Z

395

Halogen-driven low-altitude O3 and hydrocarbon losses in spring at northern high latitudes  

E-Print Network [OSTI]

; Vogt et al., 1996; Foster et al., 2001]. HOBr þ Br? þ Hþ ! Br2 þ H2OðR3? HOBr þ Cl? þ Hþ ! BrCl þ H2Oð, National Center for Atmospheric Research, Boulder, Colorado, USA. Copyright 2

Chance, Kelly

396

Experimental and Computational Study of Flame Inhibition Mechanisms of Halogenated Compounds in C1-C3 Alkanes Flames  

E-Print Network [OSTI]

suppressants on ignition and laminar flame propagation of C_(1)-C_(3) alkanes premixed mixtures, as good representatives of flammable gas fires (Class B fires). This methodology integrates model formulations and experimental designs in order to examine both...

Osorio Amado, Carmen H

2013-07-30T23:59:59.000Z

397

Fluids and halogens at the diagenetic-metamorphic boundary: evidence from veins in continental basins, western Norway  

E-Print Network [OSTI]

basins, western Norway H. SVENSEN1 , B. JAMTVEIT1 , D. A. BANKS2 AND D. KARLSEN1 1 Department of Geology, University of Oslo, Blindern, Oslo, Norway; 2 School of Earth Sciences, University of Leeds, Leeds, UK, Kvamshesten and Solund basins) in western Norway. These include calcite-, quartz- and epidote-dominated veins

Banks, David

398

Kinetic Modeling of Halogen-Based Plasma Etching of Complex Oxide Films and its Application to Predictive Feature Profile Simulation  

E-Print Network [OSTI]

initialize(int part_type,double enrgy) int j; type =part_type; energy = enrgy; //coutenrgy, double Ion_yield[NO_ION_

Marchack, Nathan

2012-01-01T23:59:59.000Z

399

Two versatile cofactors, flavin adenine dinucleotide and non-heme iron, involved in DNA repair and natural product halogenation  

E-Print Network [OSTI]

Cofactors assist enzymes with a variety of complex chemistries. Two versatile cofactors, flavin adenine dinucleotide (FAD) and non-heme iron, together with molecular oxygen as an oxidizing agent, perform a wide array of ...

Wong, Cintyu

2009-01-01T23:59:59.000Z

400

Kinetic Modeling of Halogen-Based Plasma Etching of Complex Oxide Films and its Application to Predictive Feature Profile Simulation  

E-Print Network [OSTI]

calculations, it was predicted that at typical plasma reactorof calculation. The etch rate of HfO 2 in this reactor at -calculation to be valid, it must also be assumed that at the operating conditions of the ICP reactor,

Marchack, Nathan

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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

Environ. Sci. Technol. M92, 26,2454-2461 In-Situ Transformation of Carbon Tetrachloride and Other Halogenated  

E-Print Network [OSTI]

Environ. Sci. Technol. M92, 26,2454-2461 In-Situ Transformation of Carbon Tetrachloride and Other, California 94305-4020 Enhanced in-situ transformation of carbon tetrachloride (CT) was observed under anoxic Chlorinated aliphatic hydrocarbons (CAHs)with one or two carbon atoms are widely used as solvents, degreasing

Semprini, Lewis

402

Kinetic Modeling of Halogen-Based Plasma Etching of Complex Oxide Films and its Application to Predictive Feature Profile Simulation  

E-Print Network [OSTI]

model for Si etching by fluorocarbon plasmas." Journal Ofwith inductively coupled fluorocarbon plasmas." Journal ofwith inductively coupled fluorocarbon plasmas." Journal of

Marchack, Nathan

2012-01-01T23:59:59.000Z

403

Recovery of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) from Ralstonia eutropha cultures with non-halogenated solvents  

E-Print Network [OSTI]

Reduced downstream costs, together with high purity recovery of polyhydroxyalkanoate (PHA), will accelerate the commercialization of high quality PHA-based products. In this work, a process was designed for effective ...

Riedel, Sebastian L.

404

Gas Phase Reactions between Fuel Molecules and Halogens: A Review of the Reaction between Atomic Chlorine and Ammonia  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun with Big Sky Learning Fun with Big SkyDIII-DRMRGammaEstimates - Steven Ewa

405

Energy efficient synthesis of boranes  

DOE Patents [OSTI]

The reaction of halo-boron compounds (B--X compounds, compounds having one or more boron-halogen bonds) with silanes provides boranes (B--H compounds, compounds having one or more B--H bonds) and halosilanes. Inorganic hydrides, such as surface-bound silane hydrides (Si--H) react with B--X compounds to form B--H compounds and surface-bound halosilanes. The surface bound halosilanes are converted back to surface-bound silanes electrochemically. Halo-boron compounds react with stannanes (tin compounds having a Sn--H bond) to form boranes and halostannanes (tin compounds having a Sn--X bond). The halostannanes are converted back to stannanes electrochemically or by the thermolysis of Sn-formate compounds. When the halo-boron compound is BCl.sub.3, the B--H compound is B.sub.2H.sub.6, and where the reducing potential is provided electrochemically or by the thermolysis of formate.

Thorn, David L. (Los Alamos, NM); Tumas, William (Los Alamos, NM); Schwarz, Daniel E. (Los Alamos, NM); Burrell, Anthony K. (Los Alamos, NM)

2010-11-23T23:59:59.000Z

406

Energy efficient synthesis of boranes  

DOE Patents [OSTI]

The reaction of halo-boron compounds (B--X compounds, compounds having one or more boron-halogen bonds) with silanes provides boranes (B--H compounds, compounds having one or more B--H bonds) and halosilanes. Inorganic hydrides, such as surface-bound silane hydrides (Si--H) react with B--X compounds to form B--H compounds and surface-bound halosilanes. The surface bound halosilanes are converted back to surface-bound silanes electrochemically. Halo-boron compounds react with stannanes (tin compounds having a Sn--H bond) to form boranes and halostannanes (tin compounds having a Sn--X bond). The halostannanes are converted back to stannanes electrochemically or by the thermolysis of Sn-formate compounds. When the halo-boron compound is BCl.sub.3, the B--H compound is B.sub.2H.sub.6, and where the reducing potential is provided electrochemically or by the thermolysis of formate.

Thorn, David L (Los Alamos, NM); Tumas, William (Los Alamos, NM); Schwarz, Daniel E (Los Alamos, NM); Burrell, Anthony K (Los Alamos, NM)

2012-01-24T23:59:59.000Z

407

Problem 7-3: The air enters with a dry-bulb temperature of 50 o F and, at 50% relative humidity, with a wet-  

E-Print Network [OSTI]

cooling water leaves the condenser at To = 8 o F below the temperature of the condensing steam water, leaving the cooling tower and entering the condenser at TCWin = 70 o F, this amount of heat requires a temperature rise in the condenser and corresponding temperature drop in the cooling tower

408

Residential and Transport Energy Use in India: Past Trend and Future Outlook  

E-Print Network [OSTI]

type of lighting bulb (incandescent, fluorescent), number ofof incandescent bulbs and fluorescent tubes per household,incandescent bulbs of 60W and 2.1 fluorescent tubes of 40W

de la Rue du Can, Stephane

2009-01-01T23:59:59.000Z

409

ENERGY & ENVIRONMENT DIVISION. ANNUAL REPORT FY 1980  

E-Print Network [OSTI]

lights 100 W bulb to fluorescent (1) Storm windows Centraldamper 100 W bulb to fluorescent (2) R-11 insulationin walls 3-way bulb to fluorescent Caulking Gas range Window

Authors, Various

2010-01-01T23:59:59.000Z

410

Summary of Information and Resources Related to Energy Use in Healthcare Facilities - Version 1  

E-Print Network [OSTI]

57- 57 $YESNO. - FLUOR8 Fluorescent bulbs 59- 59 $YESNO. -CFLR8 Compact fluorescent bulbs 61- 61 $YESNO. - HID8 Highof bulbs 67- 67 $YESNO. - FLUORP8 Percent lit by fluorescent

Singer, Brett C.

2010-01-01T23:59:59.000Z

411

Comparison of Test Procedures and Energy Efficiency Criteria in Selected International Standards and Labeling Programs for Clothes Washers, Water Dispensers, Vending Machines and CFLs  

E-Print Network [OSTI]

top_runner//tr_fluorescent_light_bulb_jul.2009.pdf NiskinSubcommittee Final Report (bulb type fluorescent lamp). Fluorescent Lamps (CFLs) are an efficient lighting alternative to traditional incandescent light bulbs

Fridley, David

2010-01-01T23:59:59.000Z

412

502 SHORT COMMUNICATIONS (Speotyto cuniculuria) to a moving object when the  

E-Print Network [OSTI]

the window. A red, 7-watt incandescent bulb inside the box provided illumina- tion for viewing the owl conditions were provided by one and four `I-watt incandescent bulbs, respectively. The single bulb

Minnesota, University of

413

March 10, 2011 Let There Be More Efficient Light  

E-Print Network [OSTI]

standards for light bulbs, which include a phasing out of incandescent bulbs in favor of more energy lyrically with two colleagues about "the incandescent bulb that has been turning back the night ever since

Colorado at Boulder, University of

414

Resolve to Save Energy This Year | Department of Energy  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

STAR bulbs, you could save 75 a year in energy costs. Compared to traditional incandescent bulbs, compact fluorescent bulbs can yield as much as 75 percent energy savings and...

415

Demand for Environmentally-Friendly Durables  

E-Print Network [OSTI]

the replacement of short-lived incandescent bulbs with long-the replacement of short-lived incandescent bulbs with long-15 watt CFL for 60 watt incandescent bulb), durable (minimum

Martin, Leslie Aimee

2012-01-01T23:59:59.000Z

416

Residential and Transport Energy Use in India: Past Trend and Future Outlook  

E-Print Network [OSTI]

type of lighting bulb (incandescent, fluorescent), number ofhouseholds possessed 3.2 incandescent bulbs of 60W and 2.1areas versus only 2.1 incandescent bulbs of 60W and 1.5

de la Rue du Can, Stephane

2009-01-01T23:59:59.000Z

417

Recommendations to Reduce Light Pollution and Energy Costs on the  

E-Print Network [OSTI]

(PAT18, PAT19, PAT27, PAT28, PAT29 - CL14): #12;· Change class #15, and class #20, incandescent bulbs with exterior fluorescent bulbs: · Change class #18 incandescent flood-light bulbs with fluorescent flood

418

The Influence of Photoperiod History on Circadian Response to Light  

E-Print Network [OSTI]

by broad spectrum white fluorescent bulbs (F4T5) (105 by broad spectrum white fluorescent bulbs (F4T5) (105 used broad spectrum white fluorescent bulbs (F4T5) (105 W/

Glickman, Gena Lynne

419

Characterization of EER4 and SAR1 in Relation to Their Role in Ethylene Signaling and Dampening Responses  

E-Print Network [OSTI]

Sylvania Cool White fluorescent bulbs, Danvers, MA) at 20 oSylvania Gro-Lite fluorescent bulbs, Danvers, MA) at 21 o C

Robles, Linda

2010-01-01T23:59:59.000Z

420

Zinc Oxide and Nitride Nanowire Based Light Emitting Diodes  

E-Print Network [OSTI]

only be able to find incandescent lightbulbs and fluorescent10: Output spectra of incandescent light bulb, fluorescentemission spectra. The incandescent light bulb for example

Lai, Elaine Michelle

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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

--No Title--  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

alike can also reduce power demand, and thus carbon emissions, by replacing the incandescent bulbs in their homes with energy-saving compact fluorescent bulbs. That's a handy...

422

--No Title--  

Broader source: Energy.gov (indexed) [DOE]

light bulbs, which use 75 percent less energy and last ten times longer than incandescent bulbs, (2) window installation kits, which would improve heat instillation in the...

423

--No Title--  

Broader source: Energy.gov (indexed) [DOE]

out fixtures to accommodate compact fluorescent bulbs instead of relying on incandescent bulbs. Energy Efficiency and Conservation Block Grants Native Village of Stevens...

424

DOE/LX/07-0087&D1 Secondary Document DMSA C-333-41 Solid Waste...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

included welding rods, solder, a Nissen metal marker, fluorescent light starters, incandescent light bulbs and ends, fluorescent light bulb ends, miscellaneous lead pieces, and...

425

DOE/LX/07-0242&D1 Secondary Document DMSA C-400-05 Solid Waste...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

fuses, three capacitors, three circuit boards, sixteen vacuum tubes, thirty-two incandescent light bulbs or fluorescent light bulbs, gallon of nitric acid, five aerosol...

426

CX-000133: Categorical Exclusion Determination | Department of...  

Broader source: Energy.gov (indexed) [DOE]

the funding permits. Residences for the retrofits will be selected based on need. Incandescent bulbs would be replaced with compact fluorescent bulbs. Power consumption would be...

427

IMPROVING ENERGY EFFICIENCY AND REDUCING COSTS IN THE DRINKING WATER SUPPLY INDUSTRY: An ENERGY STAR Resource Guide for Energy and Plant Managers  

E-Print Network [OSTI]

energy consumed by an incandescent bulb is emitted in thefluorescent (CFL), and incandescent lights typically arelamps in place of incandescent bulbs in most cases; and

Brown, Moya Melody, Camilla Dunham Whitehead, Rich

2011-01-01T23:59:59.000Z

428

DOE/LX/07-0315&D1 Secondary Document DMSA C-333-14 Solid Waste...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Newly discovered RCRA regulated hazardousmixed waste formerly stored consisted of incandescent light bulbs and light bulb ends, respirator canisters, aerosol cans, and lead...

429

DOE/LX/07-0323&D1 Secondary Document DMSA C-333-15 and DMSA C...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

waste formerly stored consisted of a fuse, circuit boards, light bulbs, broken incandescent light bulbs, a light starter, and a container of hand table sludge. The Toxic...

430

Estimate of Cost-Effective Potential for Minimum Efficiency Performance Standards in 13 Major World Economies Energy Savings, Environmental and Financial Impacts  

E-Print Network [OSTI]

lighting, we assume that incandescent bulbs have a one-yeargigaton Indonesia India incandescent Lamp Japan Koreaprice data for 60-watt incandescent bulbs, excluding non-

Letschert, Virginie E.

2013-01-01T23:59:59.000Z

431

CX-000137: Categorical Exclusion Determination | Department of...  

Broader source: Energy.gov (indexed) [DOE]

out fixtures to accommodate compact fluorescent bulbs instead of relying on incandescent bulbs. DOCUMENT(S) AVAILABLE FOR DOWNLOAD CX-000137.pdf More Documents &...

432

--No Title--  

Broader source: Energy.gov (indexed) [DOE]

the funding permits. Residences for the retrofits will be selected based on need. Incandescent bulbs would be replaced with compact fluorescent bulbs. Power consumption would be...

433

Energy Efficiency and Conservation Block Grant Program  

Broader source: Energy.gov (indexed) [DOE]

approximately 277 conventional60-watt light bulbs in tribal homes with 13-watt Light Emitting Diode (LED) bulbs; * Replacement of approximately 18 40-watt conventional fluorescent...

434

CX-004575: Categorical Exclusion Determination | Department of...  

Broader source: Energy.gov (indexed) [DOE]

approximately 277 conventional 60-watt light bulbs in tribal homes with 13-watt Light Emitting Diode (LED) bulbs; ? Replacement of approximately 18 40-watt conventional fluorescent...

435

Evaluation of Heat Stress and Strain in Electric Utility Workers  

E-Print Network [OSTI]

Outdoors Wet Bulb Globe Thermometer Equation Equation 3 -Indoors Wet Bulb Globe Thermometer Equation Equation 4 -by a mercury or alcohol thermometer that is shielded from

Brown, Eric Nicholas

2013-01-01T23:59:59.000Z

436

DOE/LX/07-0300&D1 Secondary Document DMSA OS-09 Solid Waste Management...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

a battery post connector, vehicle bulbs, collection drums of antifreeze, and various light bulbs. Newly generated RCRA hazardousmixed waste formerly stored included two wheel...

437

Microsoft Word - SWMU 214 OS-03 rev 121407 - draft.doc  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

WASTE DESCRIPTION: The SWMU is currently empty. Newly discovered RCRA regulated hazardous waste formerly stored included three light bulbs, a light bulb base, and an aerosol...

438

U.S. Department of Energy National Environmental Policy Act Categorica...  

Broader source: Energy.gov (indexed) [DOE]

and operation of a bulb eater machine to crush and package the glass of old light bulbs in accordance with EPA guidelines for disposal; upgrading the laundry dryer;...

439

Microsoft Word - SWMU 214 OS-03 rev 121407 - draft.doc  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

fuses, manometer, solder, epoxy, and light bulbs. Newly generated RCRA regulated hazardous wastes removed included light bulb, fuses, circuit boards, and waste oils. The Toxic...

440

Structural Characterization of and Plutonium Sorption on Mesoporous and Nanoparticulate Ferrihydrite  

E-Print Network [OSTI]

Emission spectrum of the fluorescent light bulbs used in theEmission spectrum of the fluorescent light bulbs used in the

Brogan, Luna Kestrel Schwaiger

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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

E-Print Network 3.0 - acid hcl solutions Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Collection: Chemistry 50 HELSINKI UNIVERSITY OF TECHNOLOGY ENE-47.153 Halogens, dioxinsHalogens, dioxinsfuransfurans Summary: -related corrosionChlorine-related corrosion...

442

What is Hazardous Hazardous waste is  

E-Print Network [OSTI]

Solvents (gas,chloroform,acetone,etc) Fluorescent light tubes and bulbs Lubricant, motor oil, and oil

de Lijser, Peter

443

Efficient defrosting of an inclined flat surface Subrata Roy *, Haribalan Kumar, Richard Anderson  

E-Print Network [OSTI]

and compared results with thermography and hot bulb type of measurements [12]. However, a correlation

Roy, Subrata

444

Mary Garden Plant List for the St. Clare Garden Santa Clara University, Santa Clara, California  

E-Print Network [OSTI]

, Blessed by Mary Petroselinum crispum Parsley, Our Lady's Lace BULBS Galanthus elwesii Snowdrop, Candlemas

Schwarz, Thomas

445

MARKET-ORIENTED COMPUTING AND GLOBAL GRIDS  

E-Print Network [OSTI]

Edison and Nikola Tesla paved the way for electricity's widespread use by inventing the electric bulb

Buyya, Rajkumar

446

HYDROPONIC VEGETABLE GARDENING Marcy Stanton, Master Gardener  

E-Print Network [OSTI]

and a water source. Lighting: A simple 2-bulb 4-foot fluorescent fixture with standard COOL WHITE bulbs is adequate for most leafy vegetables. Do not buy any of the fancy fluorescent grow bulbs; you are wasting your money on these expensive bulbs. When we set up a fluorescent light system to grow vegetables, what

New Hampshire, University of

447

RPI students supporting education outreach Target Audience: Elementary school students (grades 3-6)  

E-Print Network [OSTI]

) Lowe's or Home Depot Approx. $22.00 each Compact Fluorescent Bulb 40 Lumen equivalent (GE) Lowe Introduction and Bulb Comparison; LED, Compact Fluorescent, Incandescent Bulb Comparison #12;Resistor Kit (incl (top position), compact fluorescent (middle position), LED Bulb (lower position). Computer set up

Linhardt, Robert J.

448

Basic Circuit Measurements and Ohm's Law ECE 2100 Circuit Analysis Laboratory  

E-Print Network [OSTI]

, _______ W low-wattage incandescent light bulb. Also, measure and record the "cold" resistance of such a bulb. 6. Construct the circuit below using the low-wattage incandescent bulb of step 5. Use the Variac frequency. 7. Repeat steps 5 and 6 using a high-wattage incandescent light bulb rated at 120 VAC, ______ W

Miller, Damon A.

449

sexual reproduction vegetative reproduction  

E-Print Network [OSTI]

2006 3 1 2 3 physiological integration 1 coppice, sprout propagule subterranean stem bulb corm tuber

Tomimatsu,, Hiroshi

450

The Multiphase Halo of NGC 891: WIYN H-alpha and BVI Imaging  

E-Print Network [OSTI]

We present new, deep optical images (BVI+H-alpha) of the interstellar medium (ISM) far above the plane of NGC 891. These sub-arcsecond images give a direct visual view of two physically distinct ``phases'' of the thick interstellar disk of this galaxy. A dense phase of the thick disk ISM is observed in our BVI images as highly-structured dust-bearing clouds viewed against the stellar light of the galaxy. These structures are traceable to heights |z|=2 kpc from the midplane. Very few highly-structured dust features are present at |z|>2 kpc. The more prominent dust structures have gas masses in excess of 10^5 solar masses, each having visual extinctions well in excess of unity. A warm ionized phase of the high-z ISM is observed through its well-studied H-alpha emission. Our images of the well-studied diffuse ionized medium, to date the highest-resolution observations of this phase of the ISM in NGC 891, show it is relatively smoothly distributed with some filamentary structure superposed on this smooth background. There is little correspondence between the H-alpha emitting material and the absorbing dust structures. These two phases of the multiphase high-z ISM are physically distinct. The H-alpha emission is being heavily extincted in many places by the dense dust-bearing medium. Our H-alpha observations show evidence for several discrete H II regions at large distances from the midplane (to |z|=2 kpc). The presence of these H II regions in the thick disk of NGC 891 suggests that on-going star formation may be present in some of the dense, high-z clouds visible in our images. (Abstract Abridged)

J. Christopher Howk; Blair D. Savage

1999-10-14T23:59:59.000Z

451

The archetypal one-neutron halo nucleus 11Be: controversy resolved.  

E-Print Network [OSTI]

over the purity of states in 11Be resolved using measurements at different energies. · Impressive statistics and resolution achieved using a "batch-mode" beam of the long-lived isotope 10Be. · Transfer, 865-974-4022, kgrzywac@utk.edu Funding sources: DOE Office of Science, Office of Nuclear Physics

452

Near-barrier Fusion and Transfer/Breakup induced by Weakly Bound and Exotic Halo Nuclei  

E-Print Network [OSTI]

This submission has been withdrawn by arXiv administrators because it is a duplicate of nucl-th/0610004.

C. Beck

2007-01-29T23:59:59.000Z

453

The role of neutron star mergers in the chemical evolution of the Galactic halo  

E-Print Network [OSTI]

Aims. We explore the problem of the site of production of Eu. We use also the information present in the observed spread in the Eu abundances in the early Galaxy, not only its average trend. Moreover, we extend to other heavy elements (Ba, Sr, Rb, Zr) our investigations to provide additional constraints to our results. Methods. We adopt a stochastic chemical evolution model taking into account inhomogeneous mixing. The adopted yields of Eu from neutron star mergers (NSM) and from core-collapse supernovae (SNII) are those that are able to explain the average [Eu/Fe]-[Fe/H] trend observed for solar neighborhood stars, in the framework of a well-tested homogeneous model for the chemical evolution of the MilkyWay. Rb, Sr, Zr, and Ba are produced by both the s- and r-process. The s-process contribution by spinstars is the same as in our previous papers. Results. NSM that merge in less than 10 Myr or NSM combined with a source of r-process generated by massive stars can explain the spread of [Eu/Fe] in the Galactic...

Cescutti, G; Matteucci, F; Chiappini, C; Hirschi, R

2015-01-01T23:59:59.000Z

454

Inhomogeneous Galactic halo: a possible explanation for the spread observed in s- and r- process elements  

E-Print Network [OSTI]

The considerable scatter of the s- and r-process elements observed in low-metallicity stars, compared to the small star to star scatter observed for the alpha elements, is an open question for the chemical evolution studies. We have developed a stochastic chemical evolution model, in which the main assumption is a random formation of new stars, subject to the condition that the cumulative mass distribution follows a given initial mass function. With our model we are able to reproduce the different features of alpha-elements and s-and r-process elements. The reason for this resides in the random birth of stellar masses coupled with the different stellar mass ranges from where alpha-elements and s-and r-process elements originate. In particular, the sites of production of the alpha elements are the whole range of the massive stars, whereas the mass range of production for the s- and r-process elements has an upper limit of 30 solar masses.

G. Cescutti

2007-02-21T23:59:59.000Z

455

Synthetic Approaches to Skeletally Diverse Sultams Using Vinyl- and ?-Halo Benzenesulfonamides  

E-Print Network [OSTI]

ranging from chiral auxiliaries in asymmetric synthesis,2 , 3 artificial sweeteners (saccharin) in the food industry,4 and ionic liquids serving as novel reaction media,5 to a growing number of medicinal agents. To date, there are several sultam..., in 2004, reported an innovative approach for secondary amine synthesis using the pKa properties nitrobenzenesulfonamides.10 This method has been widely utilized in both industry and academia. S NH MeOO Calculations NH MeO-0.58 -0.62+1.26-0.30 +0...

Jeon, KyuOk

2012-08-31T23:59:59.000Z

456

Enlarged Transformation Group: Star Models,Dark Matter Halos and Solar System Dynamics  

E-Print Network [OSTI]

Previously a theory has been presented which extends the geometrical structure of a real four-dimensional space-time via a field of orthonormal tetrads with an enlarged transformation group. This new transformation group, called the conservation group, contains the group of diffeomorphisms as a proper subgroup and we hypothesize that it is the foundational group for quantum geometry. The fundamental geometric object of the new geometry is the curvature vector, C^\\mu . Using the scalar Lagrangian density C^\\mu C_\\mu \\sqrt{-g}, field equations for the free field have been obtained which are invariant under the conservation group. In this paper, this theory is further extended by development of a suitable Lagrangian for a field with sources. Spherically symmetric solutions for both the free field and the field with sources are given. A stellar model and an external, free-field model are developed. The theory implies that the external stress-energy tensor has non-compact support and hence may give the geometrical foundation for dark matter. The resulting models are compared to the internal and external Schwarzschild models. The theory may explain the Pioneer anomaly and the corona heating problem.

Edward Lee Green

2014-07-25T23:59:59.000Z

457

Exploring Halo Substructure with Giant Stars: The Dynamics and Metallicity of the Dwarf Spheroidal in Bootes  

E-Print Network [OSTI]

We report the results of a spectroscopic study of the Bootes (Boo) dwarf spheroidal (dSph) galaxy carried out with the WIYN telescope and the Hydra multifiber spectrograph. Radial velocities have been measured for 58 Boo candidate stars selected to have magnitudes and colors consistent with its red and asymptotic giant branches. Within the 13' half-light radius, seven members of Boo yield a systemic velocity of V_r=95.6+-3.4 km/s and a velocity dispersion of 6.6+-2.3 km/s. This implies a mass on the order of 1 x 10^7 M_sun, similar to the inferred masses of other Galactic dSphs. Adopting a total Boo luminosity of L=1.8 x 10^4 L_sun to 8.6 x 10^4 L_sun implies M/L ~ 610 to 130, making Boo, the most distorted known Milky Way dwarf galaxy, potentially also the darkest. From the spectra of Boo member stars we estimate its metallicity to be [Fe/H] ~ -2.5, which would make it the most metal poor dSph known to date.

Ricardo R. Munoz; Jeffrey L. Carlin; Peter M. Frinchaboy; David L. Nidever; Steven R. Majewski; Richard J. Patterson

2006-06-12T23:59:59.000Z

458

Mergers and Mass Assembly of Dark Matter Halos in a Lambda Cold Dark Matter Universe  

E-Print Network [OSTI]

to EPS . . . . . . . . . . . . . . . . . . . . . . . . .Connection to EPS . . . . . . . . . . . . . . . . . . . .for Consistently Reproducing the EPS Progenitor Mass

Fakhouri, Onsi Joe

2010-01-01T23:59:59.000Z

459

Electric dipole response of $^6$He: Halo-neutron and core excitations  

E-Print Network [OSTI]

Electric dipole ($E1$) response of $^{6}$He is studied with a fully microscopic six-body calculation. The wave functions for the ground and excited states are expressed as a superposition of explicitly correlated Gaussians (CG). Final state interactions of three-body decay channels are explicitly taken into account. The ground state properties and the low-energy $E1$ strength are obtained consistently with observations. Two main peaks as well as several small peaks are found in the $E1$ strength function. The peak at the high-energy region indicates a typical macroscopic picture of the giant dipole resonance, the out-of-phase proton-neutron motion. The transition densities of the lower-lying peaks exhibit in-phase proton-neutron motion in the internal region, out-of-phase motion near the surface region, and spatially extended neutron oscillation, indicating a soft-dipole mode (SDM) and its vibrationally excited mode.

D. Mikami; W. Horiuchi; Y. Suzuki

2014-05-24T23:59:59.000Z

460

Extracting electric dipole breakup cross section of one-neutron halo nuclei from breakup observables  

E-Print Network [OSTI]

How to extract an electric dipole (E1) breakup cross section \\sigma(E1) from one- neutron removal cross sections measured by using 12C and 208Pb targets, \\sigma_(-1n)^C and \\sigma_(-1n)^Pb, respectively, is discussed. It is shown that within about 5% error, \\sigma(E1) can be obtained by subtracting \\Gamma \\sigma_(-1n)^C from \\sigma_(- 1n)^Pb, as assumed in preceding studies. However, for the reaction of weakly-bound projectiles, the scaling factor \\Gamma is found to be two times as large as that usually adopted. As a result, we obtain 13-20% smaller \\sigma(E1) of 31Ne at 250 MeV/nucleon than extracted in a previous analysis of experimental data. By compiling the values of \\Gamma obtained for several projectiles, \\Gamma=(2.30 +/- 0.41)\\exp(- S_n)+(2.43 +/- 0.21) is obtained, where S_n is the neutron separation energy. The target mass number dependence of the nuclear parts of the one-neutron removal cross section and the elastic breakup cross section is also investigated.

Kazuki Yoshida; Tokuro Fukui; Kosho Minomo; Kazuyuki Ogata

2014-07-25T23:59:59.000Z

Note: This page contains sample records for the topic "halogen bulbs halo" 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.


461

From nuclear clusters to halo globulars: Star clusters as basic galactic building blocks  

E-Print Network [OSTI]

I assess the similarities and differences between the star-formation modes in quiescent spiral galaxies versus those in violent starburst regions, including galactic nuclei. As opposed to the quiescent star-formation mode, current empirical evidence on the star-formation processes in the extreme, high-pressure environments induced by galaxy encounters strongly suggests that star cluster formation is an important and perhaps even the dominant mode of star formation in such starburst events. This implies that by using star clusters as unique diagnostic probes, we can trace a galaxy's most violent star formation history very well, at least for the past few Gyr. The sizes, luminosities, and mass estimates of the young massive star clusters are entirely consistent with what is expected for young Milky Way-type globular clusters (GCs). Recent evidence lends support to the scenario that GCs, which were once thought to be the oldest building blocks of galaxies, are still forming today.

Richard de Grijs

2006-09-05T23:59:59.000Z

462

The Automatic Predictability of Super Geomagnetic Storm from Halo CMEs Associated with Large Solar Flares  

E-Print Network [OSTI]

magnetopause and this reconnection transports energy from the solar wind into the magnetosphere (Dungey 1961.S.A Big Bear Solar Observatory, 40386 North Shore Lane, Big Bear City, CA 92314 U.S.A. Feb. 25, 2006 control systems, damage of electric power grids, etc. A geomagnetic storm is initiated when the energy

463

Relics of Cosmic Quark- Hadron Phase Transition and Massive Compact Halo Objects  

E-Print Network [OSTI]

We propose that the cold dark matter (CDM) is composed entirely of quark matter, arising from a cosmic quark-hadron transition. We show that compact gravitational objects, with masses around 0.5 (M_{\\odot}), could have evolved out of the such CDM.

Shibaji Banerjee; Abhijit Bhattacharyya; Sanjay K. Ghosh; Sibaji Raha; Bikash Sinha; Hiroshi Toki

2002-11-26T23:59:59.000Z

464

The Cosmic QCD Phase Transition, Quasi-baryonic Dark Matter and Massive Compact Halo Objects  

E-Print Network [OSTI]

We propose that the cold dark matter (CDM) is composed entirely of quark matter, arising from a cosmic quark-hadron transition. We denote this phase as "quasibaryonic", distinct from the usual baryons. We show that compact gravitational lenses, with masses around 0.5 (M_{\\odot}), could have evolved out of the quasibaryonic CDM.

Shibaji Banerjee; Abhijit Bhattacharyya; Sanjay K. Ghosh; Sibaji Raha; Bikash Sinha; Hiroshi Toki

2002-06-20T23:59:59.000Z

465

Emittance growth and halo formation in the relaxation of mismatched beams Tarcisio N. Teles,* Renato Pakter,  

E-Print Network [OSTI]

be responsible for particle losses which can cause wall damage and activation. Therefore, a quan- tification in the design of such systems. In order to estimate these, a good knowledge of the mechanisms that lead to beam [2629]. In fact, in the particular case of an initially mismatched high-intensity cold beam, it has

Levin, Yan

466

Wide-Field Kinematic Structure of Early-Type Galaxy Halos  

E-Print Network [OSTI]

de Zeeuw, P. T. , Falc on- Barroso, J. , Krajnovic, D. ,T. , Emsellem, E. , Falc on- Barroso, J. , Kuntschner, H. ,Bl azquez, P. , Falc on-Barroso, J. , Cenarro, A. J. ,

Arnold, Jacob Antony

2013-01-01T23:59:59.000Z

467

An ancient F-type subdwarf from the halo crossing the Galactic plane  

E-Print Network [OSTI]

AIMS: We selected the bluest object, WISE~J0725$-$2351, from Luhman's new high proper motion (HPM) survey based on observations with the Wide-field Infrared Survey Explorer (WISE) for spectroscopic follow-up observations. Our aim was to unravel the nature of this relatively bright ($V$$\\sim$12, $J$$\\sim$11) HPM star ($\\mu$$=$267\\,mas/yr). METHODS: We obtained low- and medium-resolution spectra with the European Southern Observatory (ESO) New Technology Telescope (NTT)/EFOSC2 and Very Large Telescope (VLT)/XSHOOTER instruments, investigated the radial velocity and performed a quantitative spectral analysis that allowed us to determine physical parameters. The fit of the spectral energy distribution based on the available photometry to low-metallicity model spectra and the similarity of our target to a metal-poor benchmark star (HD~84937) allowed us to estimate the distance and space velocity. RESULTS: As in the case of HD~84937, we classified WISE~J0725$-$2351 as sdF5: or a metal-poor turnoff star with $[Fe/H]...

Scholz, R -D; Heuser, C; Ziegerer, E; Geier, S; Niederhofer, F

2015-01-01T23:59:59.000Z

468

The UV, Lyman-alpha, and dark matter halo properties of high redshift galaxies  

E-Print Network [OSTI]

We explore the properties of high-redshift Lyman-alpha emitters (LAE), and their link with the Lyman-Break galaxy population (LBG), using a semi-analytic model of galaxy formation that takes into account resonant scattering of Lya photons in gas outflows. We can reasonably reproduce the abundances of LAEs and LBGs from redshift 3 to 7, as well as most UV LFs of LAEs. The stronger dust attenuation for (resonant) Lya photons compared to UV continuum photons in bright LBGs provides a natural interpretation to the increase of the LAE fraction in LBG samples, X_LAE, towards fainter magnitudes. The redshift evolution of X_LAE seems however very sensitive to UV magnitudes limits and EW cuts. In spite of the apparent good match between the statistical properties predicted by the model and the observations, we find that the tail of the Lya equivalent width distribution (EW > 100 A) cannot be explained by our model, and we need to invoke additional mechanisms. We find that LAEs and LBGs span a very similar dynamical ra...

Garel, T; Guiderdoni, B; Michel-Dansac, L; Hayes, M; Verhamme, A

2015-01-01T23:59:59.000Z

469

Halo formation and self-pinching of an electron beam undergoing the Weibel instability  

E-Print Network [OSTI]

areas of science: astrophysics of gamma-ray bursts (GRBs) and their afterglows6­11 and the fast ignitor

Kaganovich, Igor

470

EFFECT OF HALO BIAS AND LYMAN LIMIT SYSTEMS ON THE HISTORY OF COSMIC REIONIZATION  

SciTech Connect (OSTI)

We extend the existing analytical model of reionization by Furlanetto et al. to include the biasing of reionization sources and additional absorption by Lyman limit systems. Both effects enhance the original model in non-trivial ways, but do not change its qualitative features. Our model is, by construction, consistent with the observed evolution of the galaxy luminosity function at z {approx}< 8 and with the observed evolution of Ly{alpha} forest at z {approx}< 6. We find that the same model can match the Wilkinson Microwave Anisotropy Probe/Planck constraint on the Thompson optical depth and the South Pole Telescope and EDGES constraints on the duration of reionization for values of the relative escape fraction that are consistent with the observational measurements at lower redshifts. However, such a match is only possible if dwarf galaxies contribute substantially to the ionizing photon budget. The latter condition is inconsistent with simulations and observational upper limits on the escape fraction from dwarfs at z {approx} 3. Whether such a disagreement is due to the different nature of z > 6 galaxies, the inadequacy of simulations and/or some of the observational constraints, or indicates an additional source of ionizing radiation at z > 8 remains to be seen.

Kaurov, Alexander A.; Gnedin, Nickolay Y., E-mail: kaurov@uchicago.edu, E-mail: gnedin@fnal.gov [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)

2013-07-01T23:59:59.000Z

471

X-ray haloes and starformation in early-type galaxies  

E-Print Network [OSTI]

High resolution 2D hydrodynamical simulations describing the evolution of the hot ISM in state-of-the-art axisymmetric two-component models of early-type galaxies well reproduced the observed trends of the X-ray luminosity ($L_\\mathrm{x}$) and temperature ($T_\\mathrm{x}$) with galaxy shape