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1

PROSPECTING IN LATE-TYPE DWARFS: A CALIBRATION OF INFRARED AND VISIBLE SPECTROSCOPIC METALLICITIES OF LATE K AND M DWARFS SPANNING 1.5 dex  

SciTech Connect (OSTI)

Knowledge of late K and M dwarf metallicities can be used to guide planet searches and constrain planet formation models. However, the determination of metallicities of late-type stars is difficult because visible wavelength spectra of their cool atmospheres contain many overlapping absorption lines, preventing the measurement of equivalent widths. We present new methods, and improved calibrations of existing methods, to determine metallicities of late K and M dwarfs from moderate resolution (1300 < R < 2000) visible and infrared spectra. We select a sample of 112 wide binary systems that contain a late-type companion to a solar-type primary star. Our sample includes 62 primary stars with previously published metallicities, as well as 50 stars with metallicities determined from our own observations. We use our sample to empirically determine which features in the spectrum of the companion are best correlated with the metallicity of the primary. We find {approx_equal}120 features in K and M dwarf spectra that are useful for predicting metallicity. We derive metallicity calibrations for different wavelength ranges, and show that it is possible to get metallicities reliable to <0.10 dex using either visible, J-, H-, or K-band spectra. We find that the most accurate metallicities derived from visible spectra requires the use of different calibrations for early-type (K5.5-M2) and late-type (M2-M6) dwarfs. Our calibrations are applicable to dwarfs with metallicities of -1.04 < [Fe/H] <+0.56 and spectral types from K7 to M5. Lastly, we use our sample of wide binaries to test and refine existing calibrations to determine M dwarf metallicities. We find that the {zeta} parameter, which measures the ratio of TiO can CaH bands, is correlated with [Fe/H] for super-solar metallicities, and {zeta} does not always correctly identify metal-poor M dwarfs. We also find that existing calibrations in the K and H bands are quite reliable for stars with [Fe/H] >-0.5, but are less useful for more metal-poor stars.

Mann, Andrew W.; Hilton, Eric J. [Institute for Astronomy, University of Hawai'i, 2680 Woodlawn Dr, Honolulu, HI 96822 (United States); Brewer, John M. [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Gaidos, Eric [Department of Geology and Geophysics, University of Hawai'i, 1680 East-West Road, Honolulu, HI 96822 (United States); Lepine, Sebastien [Department of Astrophysics, American Museum of Natural History, New York, NY 10024 (United States)

2013-02-01T23:59:59.000Z

2

E-Print Network 3.0 - antiknock compounds Sample Search Results  

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

in the Supplementary Information.A ... Source: Ajayan, Pulickel M. - Department of Mechanical Engineering and Materials Science, Rice University Collection: Materials...

3

NERSC CoDEx Project: A Hardware/Software Codesign Environment for the  

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 Conchas recovery challengeMultiscale SubsurfaceExascale Era Computing » CoDEx Project

4

Lead contamination in street soils of Nairobi City and Mombasa Island, Kenya  

SciTech Connect (OSTI)

The advent of modern industrialization and, in particular, the motor vehicle has witnessed dramatic increases in lead usage both as a component of lead-acid storage battery and from 1923 as organic lead alkyl anti-knock additive in petroleum. Several workers have established a correlation between increasing lead concentration in roadside soils and vehicular traffic density. Although researchers studied the heavy metal content in Lake Victoria sediments, no urban roadside soils were investigated. Since lead is used as a petrol additive in Kenya, it is necessary to document the extent and magnitude of lead contamination of roadside soils in inland and coastal urban environments and evaluate its environmental implications.

Onyari, J.M.; Wandiga, S.O.; Njenga, G.K.; Nyatebe, J.O. (Univ. of Nairobi (Kenya))

1991-05-01T23:59:59.000Z

5

E-Print Network 3.0 - antiknock ratings Sample Search Results  

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

lens and C-mount extension tubes are ... Source: Wooldridge, Margaret S. - Departments of Mechanical Engineering & Aerospace Engineering, University of Michigan Collection:...

6

Motor gasolines, winter 1981-1982  

SciTech Connect (OSTI)

Analytical data for 905 samples of motor gasoline, were collected from service stations throughout the country and were analyzed in the laboratories of various refiners, motor manufacturers, and chemical companies. The data were submitted to the Bartlesville Energy Technology Center for study, necessary calculations, and compilation under a cooperative agreement between the Bartlesville Energy Technology Center (BETC) and the American Petroleum Institute (API). The samples represent the products of 30 companies, large and small, which manufacture and supply gasoline. These data are tabulated by groups according to brands (unlabeled) and grades for 17 marketing districts into which the country is divided. A map included in this report, shows marketing areas, districts and sampling locations. The report also includes charts indicating the trends of selected properties of motor fuels since winter 1959-1960 survey for the leaded gasolines, and since winter 1979-1980 survey for the unleaded gasolines. Sixteen octane distribution percent charts for areas 1, 2, 3, and 4 for unleaded antiknock index (R+M)/2 below 90.0, unleaded antiknock index (R+M)/2 90.0 and above, leaded antiknock index (R+M)/2 below 93.0, and leaded antiknock index (R+M)/2 93.0 and above grades of gasoline are presented in this report. The antiknock (octane) index (R+M)/2 averages of gasoline sold in this country were 87.4 for unleaded below 90.0, 91.7 for unleaded 90.0 and above, and 88.9 for leaded below 93.0. Only one sample was reported as 93.0 for leaded gasolines with an antiknock index (R+M)/2 93.0 and above.

Shelton, E M

1982-07-01T23:59:59.000Z

7

A model for the emergence of pillars, walls and royal chambers in termite nests  

E-Print Network [OSTI]

A model for the emergence of pillars, walls and royal chambers in termite nests Eric Bonabeau1, 31062 Toulouse Ce¨ dex, France A simple model of the emergence of pillars in termite nests by Deneubourg construction modi¢es current building conditions, we hypothesize that nest complexity can result from

Theraulaz, Guy

8

Anne Le Mouel, paper ID# 4-054-12 Fostering Energy Efficiency in manufacturing plants  

E-Print Network [OSTI]

economical breakthroughs in power and flow rate measurement Anne Le Mouel, EDF R&D Eco-Efficiency Cédex, FRANCE Email: anne.le-mouel@edf.fr Gilbert Schmitt, EDF R&D Eco-Efficiency & Industrial Process: gilbert-m.schmitt@edf.fr Maxime Dupont, EDF R&D Eco-Efficiency & Industrial Process Department Site des

Paris-Sud XI, Université de

9

CONTRACTNO.: DE-X13-96GJ87335 TASK ORDER NO.: h  

Office of Legacy Management (LM)

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 ofof EnergyYou$0.C. 20545 OCTTO:March_BayoRECORD OF^_. . _

10

Fuel additives. January 1984-December 1991 (Citations from the NTIS Data Base). Rept. for Jan 84-Dec 91  

SciTech Connect (OSTI)

The bibliography contains citations concerning effects; evaluations; and production methods of additives in automotive, aviation, diesel, and boiler fuels. Antioxidant, antiicing, antistatic, corrosion inhibitors, antiknock, and depressant additives relative to evaluations and testing are among the topics discussed. (Contains 165 citations with title list and subject index.)

Not Available

1991-11-01T23:59:59.000Z

11

Fuel additives. January 1970-August 1989 (Citations from the COMPENDEX data base). Report for January 1970-August 1989  

SciTech Connect (OSTI)

This bibliography contains citations concerning effects; evaluations; and production methods of additives in automotive, aviation, diesel, and boiler fuels. Antioxidant, antiicing, antistatic, corrosion inhibitors, antiknock, and depressant additives relative to evaluations and testing are among the topics discussed. (This updated bibliography contains 223 citations, 56 of which are new entries to the previous edition.)

Not Available

1989-09-01T23:59:59.000Z

12

The helium abundances in HgMn and normal stars  

E-Print Network [OSTI]

The parameter-free model of diffusion in the atmospheres of HgMn stars (Michaud 1986; Michaud et al 1979) predicts that helium should sink below the He II ionization zone in order that diffusion of other elements may take place, and that all HgMn stars should have deficits of helium in their photospheres, with a minimum deficit of 0.3 dex. In this study, the Smith & Dworetsky (1993) sample of HgMn stars and normal comparison stars is examined, and the helium abundances determined by spectrum synthesis using echelle spectra taken at Lick Observatory and the AAT. The prediction is confirmed; all HgMn stars are deficient in He by as much as 1.5 dex. Also, two HgMn stars, HR7361 and HR7664, show clear evidence of helium stratification.

M. M. Dworetsky

2004-07-26T23:59:59.000Z

13

Chemical Homogeneity in Collinder 261 and Implications for Chemical Tagging  

E-Print Network [OSTI]

This paper presents abundances for 12 red giants of the old open cluster Collinder 261 based on spectra from VLT/UVES. Abundances were derived for Na, Mg, Si, Ca, Mn, Fe, Ni, Zr and Ba. We find the cluster has a solar-level metallicity of [Fe/H] = -0.03 dex. However some alpha elements were found to be enhanced. The star-to-star scatter was consistent with the expected measurement uncertainty for all elements. The observed rms scatter is as follows: Na = 0.07, Mg = 0.05, Si = 0.06, Ca = 0.05, Mn = 0.03, Fe = 0.02, Ni = 0.04, Zr = 0.12, and Ba = 0.03 dex. The intrinsic scatter was estimated to be less than 0.05 dex. Such high levels of homogeneity indicate that chemical information remains preserved in this old open cluster. We use the chemical homogeneity we have now established in Cr 261, Hyades and the HR1614 moving group to examine the uniqueness of the individual cluster abundance patterns, ie. chemical signatures. We demonstrate that the three studied clusters have unique chemical signatures, and discuss how other such signatures may be searched for in the future. Our findings support the prospect of chemically tagging disk stars to common formation sites in order to unravel the dissipative history of the Galactic disk.

G. M. De Silva; K. C. Freeman; M. Asplund; J. Bland-Hawthorn; M. S. Bessell; R. Collet

2006-11-28T23:59:59.000Z

14

On the lithium dip in the metal poor open cluster NGC 2243  

SciTech Connect (OSTI)

Lithium is a key element for studying the mixing mechanisms operating in stellar interiors. It can also be used to probe the chemical evolution of the Galaxy and the Big Bang nucleosynthesis. Measuring the abundance of Lithium in stars belonging to Open Clusters (hereafter OC) allows a detailed comparison with stellar evolutionary models. NGC 2243 is particularly interesting thanks to its relative low metallicity ([Fe/H]=?0.54 0.10 dex). We performed a detailed analysis of high-resolution spectra obtained with the multi-object facility FLAMES at the VLT 8.2m telescope. Lithium abundance has been measured in 27 stars. We found a Li dip center of 1.06 M{sub ?}, which is significantly smaller than that observed in solar metallicity and metal-rich clusters. This finding confirms and strengthens the conclusion that the mass of the stars in the Li dip strongly depends on stellar metallicity. The mean Li abundance of the cluster is log n(Li) = 2.70 dex, which is substantially higher than that observed in 47 Tue. We derived an iron abundance of [Fe/H]=?0.540.10 dex for NGC 2243, in agreement (within the errors) with previous findings.

Franois, P. [GEPI, Paris-Meudon Observatory, 61 Avenue de l'Observatoire, F-75014 Paris (France); Pasquini, L.; Palsa, R. [ESO, European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei Mnchen (Germany); Biazzo, K. [INAF, Capodimonte Astronomical Observatory, via Moiariello 16, 80131 Naples (Italy); Bonifacio, P. [GEPI, Paris-Meudon Observatory, Place Jules Janssen 92190, Meudon (France)

2014-05-02T23:59:59.000Z

15

Quantitative Spectroscopy of 24 A supergiants in the Sculptor galaxy NGC 300: Flux weighted gravity luminosity relationship, metallicity and metallicity gradient  

E-Print Network [OSTI]

A quantitative spectral analysis of 24 A supergiants in the Sculptor Group spiral galaxy NGC 300 at a distance of 1.9 Mpc is presented. A new method is introduced to analyze low resolution (~5 AE) spectra, which yields metallicities accurate to 0.2 dex including the uncertainties arising from the errors in Teff (5%) and log g (0.2 dex). For the first time the stellar metallicity gradient based on elements such as titanium and iron in a galaxy beyond the Local Group is investigated. Solar metallicity is measured in the center and 0.3 solar in the outskirts and a logarithmic gradient of -0.08 dex/kpc. An average reddening of E(B-V)~0.12 mag is obtained, however with a large variation from 0.07 to 0.24 mag. We also determine stellar radii, luminosities and masses and discuss the evolutionary status. Finally, the observed relationship between absolute bolometric magnitudes M_{bol} and flux weighted gravities g_{F} = g/Teff^4 is investigated. At high temperatures the strengths of the Balmer lines depends solely on the flux-weighted gravity, which allows a precise direct determination of log g_{F} with an accuracy of 0.05 to 0.1 dex. We find a tight relationship between M_{bol} and log g_{F} in agreement with stellar evolution theory. Combining these new results with previous work on Local Group galaxies we obtain a new flux weighted gravity luminosity relationship (FGLR), which is very well defined and appears to be an excellent alternative tool to determine distances to galaxies.

R. -P. Kudritzki; M. A. Urbaneja; F. Bresolin; N. Przybilla; W. Gieren; G. Pietrzynski

2008-03-26T23:59:59.000Z

16

Determination of a peak benzene exposure to consumers at typical self-service gasoline stations  

E-Print Network [OSTI]

. LITERATURE REVIEW Gasoline is a complex mixture of various volatile hydrocarbons blended with several additives depend1ng on the grade of gasoline desired. The goal in blending gasoline 1s to meet two criteria: l) improve antiknock performance, and 2.... This was due to differences in blending. Those identified hydrocarbons amounted to 98 percent, by weight, of the liquid gasoline sample. Benzene in Liquid Gasoline In 1928, Askey , reported that gasolines in West California 2 might contain as much as 17...

Carapezza, Ted

2012-06-07T23:59:59.000Z

17

Post-transcriptional regulation of gene expression by the DExD/H-box protein Dhh1  

E-Print Network [OSTI]

A. , J. Rehwinkel, M. Stricker, E. Huntzinger, S.F. Yang, T.A. , J. Rehwinkel, M. Stricker, E. Huntzinger, S.F. Yang, T.

Carroll, Johanna Shumway

2011-01-01T23:59:59.000Z

18

In vitro and in vivo activation of the pituitary-adrenal axis by corticotropin-releasing factor, vasopressin (VP), and two VP analogs  

E-Print Network [OSTI]

's objectives were to: 1) compare the relative potency of a VP analog with that of CRF and VP in terms of ACTH secretion by cultured bovine corticotrophs; 2) evaluate a VP analog as an antagonist of VP-induced ACTH secretion by cultured bovine corticotrophs...; 3) evaluate the ability of CRF and VP to induce ACTH secretion in vivo in cattle; and, 4) evaluate the ability of the antiglucocorticoid, RU486, to block the inhibitory effects of dexamethasone (DEX) on CRF- and VP-induced ACTH secretion in vitro...

Carroll, Jeffery Allen

1993-01-01T23:59:59.000Z

19

3D Hydrodynamical Simulations of Surface Convection in Red Giant Stars. Impact on spectral line formation and abundance analysis  

E-Print Network [OSTI]

We investigate the impact of 3D hydrodynamical model atmospheres of red giant stars at different metallicities on the formation of spectral lines of a number of ions and molecules. We carry out realistic 3D simulations of surface convection in red giant stars with varying stellar parameters. We use the simulations as time-dependent hydrodynamical model stellar atmospheres to compute atomic (Li, O, Na, Mg, Ca, Fe) and molecular (CH, NH, OH) spectral lines under the assumption of local thermodynamic equilibrium (LTE). We compare the line strengths computed in 3D with the results of analogous line formation calculations for 1D, hydrostatic, plane-parallel MARCS model atmospheres in order to estimate the impact of 3D models on the derivation of elemental abundances. The temperature and density inhomogeneities and correlated velocities in 3D models, as well as the differences between the 1D and mean 3D structures significantly affect the predicted line strengths. Under the assumption of LTE, the low atmospheric temperatures of very metal-poor 3D model atmospheres cause the lines from neutral species and molecules to appear stronger than in 1D. Therefore, elemental abundances derived from these lines using 3D models are significantly lower than according to 1D analyses. Differences between 3D and 1D abundances of C, N, and O derived from CH, NH, and OH weak low-excitation lines are found to be in the range -0.5 dex to -1.0 dex for the the red giant stars at [Fe/H]=-3 considered here. At this metallicity, large negative corrections (about -0.8 dex) are also found for weak low-excitation Fe I lines. We caution, however, that departures from LTE might be significant for these and other elements and comparable to the effects due to stellar granulation.

Remo Collet; Martin Asplund; Regner Trampedach

2007-03-26T23:59:59.000Z

20

Non-LTE metal abundances in V652 Her and HD144941  

E-Print Network [OSTI]

Two evolutionary scenarios are proposed for the formation of extreme helium stars: a post-AGB star suffering from a late thermal pulse, or the merger of two white dwarfs. An identification of the evolutionary channel for individual objects has to rely on surface abundances. We present preliminary results from a non-LTE analysis of CNO, Mg and S for two unique objects, V652 Her and HD144941. Non-LTE abundance corrections for these elements range from negligible values to ~0.7 dex. Non-LTE effects typically lead to systematic shifts in the abundances relative to LTE and reduce the uncertainties.

N. Przybilla; M. F. Nieva; U. Heber; C. S. Jeffery

2005-12-06T23:59:59.000Z

Note: This page contains sample records for the topic "antiknock in dex" 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

Magnesium Isotope Ratios in omega Centauri Red Giants  

E-Print Network [OSTI]

We have used high resolution observations obtained at the AAT with UHRF (R ~ 100,000) and at Gemini-S with b-HROS (R ~ 150,000) to determine magnesium isotope ratios for seven omega Centauri red giants that cover a range in iron abundance from [Fe/H] = --1.78 to --0.78 dex, and for two red giants in M4 (NGC 6121). The omega Centauri stars sample both the "primordial" (i.e., O-rich, Na and Al-poor) and the "extreme" (O-depleted, Na and Al-rich) populations in the cluster. The primordial population stars in both omega Centauri and M4 show (25Mg, 26Mg)/24 Mg isotopic ratios that are consistent with those found for the primordial population in other globular clusters with similar [Fe/H] values. The isotopic ratios for the omega Centauri extreme stars are also consistent with those for extreme population stars in other clusters. The results for the extreme population stars studied indicate that the 26Mg/24Mg ratio is highest at intermediate metallicities ([Fe/H] < --1.4 dex), and for the highest [Al/Fe] values....

Da Costa, G S; Yong, David

2013-01-01T23:59:59.000Z

22

Optical Spectroscopy of Supernova Remnants in M81 and M82  

E-Print Network [OSTI]

We present spectroscopy of 28 SNR candidates as well as one H II region in M81, and two SNR candidates in M82. Twenty six out of the M81 candidates turn out to be genuine SNRs, and two in M82 may be shocked condensations in the galactic outflow or SNRs. The distribution of [N II]/H{\\alpha} ratios of M81 SNRs is bimodal. M81 SNRs are divided into two groups in the spectral line ratio diagrams: an [O III]-strong group and an [O III]-weak group. The latter have larger sizes, and may have faster shock velocity. [N II]/H{\\alpha} ratios of the SNRs show a strong correlation with [S II]/H{\\alpha} ratios. They show a clear radial gradient in [N II]/H{\\alpha} and [S II]/H{\\alpha} ratios: dLog ([N II]/H{\\alpha})/dLog R = -0.018 {\\pm} 0.008 dex/kpc and dLog ([S II]/H{\\alpha})/dLog R = -0.016 {\\pm} 0.008 dex/kpc where R is a deprojected galactocentric distance. We estimate the nitrogen and oxygen abundance of the SNRs from the comparison with shock-ionization models. We obtain a value for the nitrogen radial gradient, dL...

Lee, Myung Gyoon; Lee, Jong Hwan; Lim, Sungsoon; Jang, In Sung; Ko, Youkyung; Koo, Bon-Chul; Hwang, Narae; Kim, Sang Chul; Park, Byeong-Gon

2015-01-01T23:59:59.000Z

23

Oxygen abundances in planet-harbouring stars. Comparison of different abundance indicators  

E-Print Network [OSTI]

We present a detailed and uniform study of oxygen abundances in 155 solar type stars, 96 of which are planet hosts and 59 of which form part of a volume-limited comparison sample with no known planets. EW measurements were carried out for the [O I] 6300 \\AA line and the O I triplet, and spectral synthesis was performed for several OH lines. NLTE corrections were calculated and applied to the LTE abundance results derived from the O I 7771-5 \\AA\\ triplet. Abundances from [O I], the O I triplet and near-UV OH were obtained in 103, 87 and 77 dwarfs, respectively. We present the first detailed and uniform comparison of these three oxygen indicators in a large sample of solar-type stars. There is good agreement between the [O/H] ratios from forbidden and OH lines, while the NLTE triplet shows a systematically lower abundance. We found that discrepancies between OH, [O I] and the O I triplet do not exceed 0.2 dex in most cases. We have studied abundance trends in planet host and comparison sample stars, and no obvious anomalies related to the presence of planets have been detected. All three indicators show that, on average, [O/Fe] decreases with [Fe/H] in the metallicity range -0.8oxygen overabundance of 0.1-0.2dex with respect to the comparison sample.

A. Ecuvillon; G. Israelian; N. C. Santos; N. G. Shchukina; M. Mayor; R. Rebolo

2005-09-13T23:59:59.000Z

24

Are oxygen and neon enriched in PNe and is the current solar Ne/O abundance ratio underestimated?  

E-Print Network [OSTI]

A thorough critical literature survey has been carried out for reliable measurements of oxygen and neon abundances of planetary nebulae (PNe) and HII regions. By contrasting the results of PNe and of HII regions, we aim to address the issues of the evolution of oxygen and neon in the interstellar medium (ISM) and in the late evolutionary phases of low- and intermediate-mass stars (LIMS), as well as the currently hotly disputed solar Ne/O abundance ratio. Through the comparisons, we find that neon abundance and Ne/O ratio increase with increasing oxygen abundance in both types of nebulae, with positive correlation coefficients larger than 0.75. The correlations suggest different enrichment mechanisms for oxygen and neon in the ISM, in the sense that the growth of neon is delayed compared to oxygen. The differences of abundances between PNe and HII regions, are mainly attributed to the results of nucleosynthesis and dredge-up processes that occurred in the progenitor stars of PNe. We find that both these alpha-elements are significantly enriched at low metallicity (initial oxygen abundance oxygen in intermediate mass stars (IMS) of low initial metallicities and in more massive stars, a conjecture that requires verification by further theoretical studies. This result also strongly suggests that both the solar neon abundance and the Ne/O ratio should be revised upwards by ~0.22 dex from the Asplund, Grevesse & Sauval values or by ~0.14 dex from the Grevesse & Sauval values.

W. Wang; X. -W. Liu

2008-06-13T23:59:59.000Z

25

THE METALLICITY DEPENDENCE OF THE CEPHEID P L RELATION IN M101  

SciTech Connect (OSTI)

The impact of metallicity on the Cepheid period-luminosity (P L) relation is investigated using Hubble Space Telescope Advanced Camera for Surveys V and I images of M101. Variations in the reddening-free Wesenheit parameter (W), which is employed as a proxy for luminosity, are examined as a function of the radial distance from the center of M101 (and thus metallicity). We determine that there is no dependence of the slope on metallicity. However, the intercept is found to depend on metallicity by ?{sub VI} = 0.33 0.12 mag dex{sup 1} and ?{sub VI} = 0.71 0.17 mag dex{sup 1} using 2? and 3? rejection criteria, respectively. Sigma-clipping impacts the derived metallicity dependence, and the 2? criterion applied likely mitigates blending, particularly in the crowded inner regions of M101. A metallicity-corrected distance for M101 is obtained from 619 Cepheids (? = 28.96 0.11), a result that agrees with the recently determined SN Ia distance. The metallicity effects described can be bypassed by working at near and mid-infrared wavelengths (e.g., the Carnegie Hubble Program)

Mager, Violet A.; Madore, Barry F.; Freedman, Wendy L., E-mail: mager@susqu.edu, E-mail: barry@obs.carnegiescience.edu, E-mail: wendy@obs.carnegiescience.edu [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)

2013-11-01T23:59:59.000Z

26

Stromgren photometry of Galactic Globular Clusters. II Metallicity distribution of red giants in Omega Centauri  

E-Print Network [OSTI]

We present new intermediate-band Stroemgren photometry based on more than 300 u,v,b,y images of the Galactic globular cluster Omega Cen. Optical data were supplemented with new multiband near-infrared (NIR) photometry (350 J,H,K_s images). The final optical-NIR catalog covers a region of more than 20*20 arcmin squared across the cluster center. We use different optical-NIR color-color planes together with proper motion data available in the literature to identify candidate cluster red giant (RG) stars. By adopting different Stroemgren metallicity indices we estimate the photometric metallicity for ~4,000 RGs, the largest sample ever collected. The metallicity distributions show multiple peaks ([Fe/H]_phot=-1.73+/-0.08,-1.29+/-0.03,-1.05+/-0.02,-0.80+/-0.04,-0.42+/-0.12 and -0.07+/-0.08 dex) and a sharp cut-off in the metal-poor tail ([Fe/H]_phot-1.7 dex).

Calamida, A; Stetson, P B; Freyhammer, L M; Piersimoni, A M; Buonanno, R; Caputo, F; Cassisi, S; Castellani, M; Corsi, C E; Dall'Ora, M; Degl'Innocenti, S; Ferraro, I; Grundahl, F; Hilker, M; Monelli, M; Nonino, M; Patat, N; Pietrinferni, A; Moroni, P G Prada; Primas, F; Pulone, L; Richtler, T; Romaniello, M; Storm, J; Walker, A R

2009-01-01T23:59:59.000Z

27

STAR-TO-STAR IRON ABUNDANCE VARIATIONS IN RED GIANT BRANCH STARS IN THE GALACTIC GLOBULAR CLUSTER NGC 3201  

SciTech Connect (OSTI)

We present the metallicity as traced by the abundance of iron in the retrograde globular cluster NGC 3201, measured from high-resolution, high signal-to-noise spectra of 24 red giant branch stars. A spectroscopic analysis reveals a spread in [Fe/H] in the cluster stars at least as large as 0.4 dex. Star-to-star metallicity variations are supported both through photometry and through a detailed examination of spectra. We find no correlation between iron abundance and distance from the cluster core, as might be inferred from recent photometric studies. NGC 3201 is the lowest mass halo cluster to date to contain stars with significantly different [Fe/H] values.

Simmerer, Jennifer; Ivans, Inese I.; Filler, Dan [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Francois, Patrick [Paris-Meudon Observatory, France and Universite de Picardie Jules Verne, F-80080 Amiens (France); Charbonnel, Corinne [Geneva Observatory, University of Geneva, Chemin des Maillettes 51, CH-1290 Versoix (Switzerland); Monier, Richard [Laboratoire Hippolyte Fizeau, Universite Nice Sophia Antipolis, Parc Valrose, F-06000 Nice (France); James, Gaeel, E-mail: jennifer@physics.utah.edu, E-mail: iii@physics.utah.edu, E-mail: dan.filler@utah.edu, E-mail: patrick.francois@obspm.fr, E-mail: corinne.charbonnel@unige.ch, E-mail: richard.monier@unice.fr, E-mail: gjames@eso.org [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei Munchen (Germany)

2013-02-10T23:59:59.000Z

28

MAGNESIUM ISOTOPE RATIOS IN {omega} CENTAURI RED GIANTS  

SciTech Connect (OSTI)

We have used the high-resolution observations obtained at the Anglo-Australian Telescope with Ultra-High Resolution Facility (R {approx} 100,000) and at Gemini-S with b-HROS (R {approx} 150,000) to determine magnesium isotope ratios for seven {omega} Cen red giants that cover a range in iron abundance from [Fe/H] = -1.78 to -0.78 dex, and for two red giants in M4 (NGC 6121). The {omega} Cen stars sample both the ''primordial'' (i.e., O-rich, Na- and Al-poor) and the ''extreme'' (O-depleted, Na- and Al-rich) populations in the cluster. The primordial population stars in both {omega} Cen and M4 show ({sup 25}Mg, {sup 26}Mg)/{sup 24}Mg isotopic ratios that are consistent with those found for the primordial population in other globular clusters with similar [Fe/H] values. The isotopic ratios for the {omega} Cen extreme stars are also consistent with those for extreme population stars in other clusters. The results for the extreme population stars studied indicate that the {sup 26}Mg/{sup 24}Mg ratio is highest at intermediate metallicities ([Fe/H] < -1.4 dex), and for the highest [Al/Fe] values. Further, the relative abundance of {sup 26}Mg in the extreme population stars is notably higher than that of {sup 25}Mg, in contrast to model predictions. The {sup 25}Mg/{sup 24}Mg isotopic ratio in fact does not show any obvious dependence on either [Fe/H] or [Al/Fe] nor, intriguingly, any obvious difference between the primordial and extreme population stars.

Da Costa, G. S.; Norris, John E.; Yong, David [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 0200 (Australia)

2013-05-20T23:59:59.000Z

29

Bourses thses Org Domaine Dure Dead line Particularit Lien  

E-Print Network [OSTI]

neurodénératives FONDATION MOTRICE avril http://www.lafondationmotrice.org/in dex://www.fdv-paris.org/fr/ecole- doctorale-fdv/ FONDATION MOTRICE avril may France ou étranger http://www.lafondationmotrice.org/in dex

Arleo, Angelo

30

Line formation in solar granulation: III. The photospheric Si and meteoritic Fe abundances  

E-Print Network [OSTI]

Using realistic hydrodynamical simulations of the solar surface convection as 3D, time-dependent, inhomogeneous model atmospheres, the solar photospheric Si abundance has been determined to be log Si = 7.51 +- 0.04. This constitutes a difference of 0.04 dex compared with previous estimates based on the 1D Holweger-M\\"uller (1974) model, of which half is attributable to the adopted model atmosphere and the remaining part to the improved quantum mechanical broadening treatment. As a consequence, all meteoritic abundances should be adjusted downwards by the same amount. In particular the meteoritic Fe abundance will be log Fe = 7.46 +- 0.01, in good agreement with the recently determined photospheric Fe abundance (Asplund et al. 2000b). The existing uncertainties unfortunately prevent an observational confirmation of the postulated effects of elemental migration of metals in the Sun.

M. Asplund

2000-05-15T23:59:59.000Z

31

Oxygen abundances in metal-poor subgiants as determined from [O I], O I and OH lines  

E-Print Network [OSTI]

The debate on the oxygen abundances of metal-poor stars has its origin in contradictory results obtained using different abundance indicators. To achieve a better understanding of the problem we have acquired high quality spectra with the Ultraviolet and Visual Echelle Spectrograph at VLT, with a signal-to-noise of the order of 100 in the near ultraviolet and 500 in the optical and near infrared wavelength range. Three different oxygen abundance indicators, OH ultraviolet lines around 310.0 nm, the [OI] line at 630.03 nm and the OI lines at 777.1-5 nm were observed in the spectra of 13 metal-poor subgiants with -3.0Oxygen abundances were obtained from the analysis of these indicators which was carried out assuming local thermodynamic equilibrium and plane-parallel model atmospheres. Abundances derived from OI were corrected for departures from local thermodynamic equilibrium. Stellar parameters were computed using Teff-vs-color calibrations based on the infrared flux method and Balmer line profiles, Hipparcos parallaxes and FeII lines. [O/Fe] values derived from the forbidden line at 630.03 nm are consistent with an oxygen/iron ratio that varies linearly with [Fe/H] as [O/Fe]}=-0.09(+/-0.08)[Fe/H]+0.36(+/-0.15). Values based on the OI triplet are on average 0.19+/-0.22 dex(s.d.) higher than the values based on the forbidden line while the agreement between OH ultraviolet lines and the forbidden line is much better with a mean difference of the order of -0.09+/-0.25 dex(s.d.). In general, our results follow the same trend as previously published results with the exception of the ones based on OH ultraviolet lines. In that case our results lie below the values which gave rise to the oxygen abundance debate for metal-poor stars.

A. E. Garca Prez; M. Asplund; F. Primas; P. E. Nissen; B. Gustafsson

2005-12-12T23:59:59.000Z

32

METAL ABUNDANCES, RADIAL VELOCITIES, AND OTHER PHYSICAL CHARACTERISTICS FOR THE RR LYRAE STARS IN THE KEPLER FIELD  

SciTech Connect (OSTI)

Spectroscopic iron-to-hydrogen ratios, radial velocities, atmospheric parameters, and new photometric analyses are presented for 41 RR Lyrae stars (and one probable high-amplitude {delta} Sct star) located in the field-of-view of the Kepler space telescope. Thirty-seven of the RR Lyrae stars are fundamental-mode pulsators (i.e., RRab stars) of which sixteen exhibit the Blazhko effect. Four of the stars are multiperiodic RRc pulsators oscillating primarily in the first-overtone mode. Spectroscopic [Fe/H] values for the 34 stars for which we were able to derive estimates range from -2.54 {+-} 0.13 (NR Lyr) to -0.05 {+-} 0.13 dex (V784 Cyg), and for the 19 Kepler-field non-Blazhko stars studied by Nemec et al. the abundances agree will with their photometric [Fe/H] values. Four non-Blazhko RR Lyrae stars that they identified as metal-rich (KIC 6100702, V2470 Cyg, V782 Cyg and V784 Cyg) are confirmed as such, and four additional stars (V839 Cyg, KIC 5520878, KIC 8832417, KIC 3868420) are also shown here to be metal-rich. Five of the non-Blazhko RRab stars are found to be more metal-rich than [Fe/H] {approx}-0.9 dex while all of the 16 Blazhko stars are more metal-poor than this value. New P-{phi}{sub 31}{sup s}-[Fe/H] relationships are derived based on {approx}970 days of quasi-continuous high-precision Q0-Q11 long- and short-cadence Kepler photometry. With the exception of some Blazhko stars, the spectroscopic and photometric [Fe/H] values are in good agreement. Several stars with unique photometric characteristics are identified, including a Blazhko variable with the smallest known amplitude and frequency modulations (V838 Cyg)

Nemec, James M. [Department of Physics and Astronomy, Camosun College, Victoria, British Columbia, V8P 5J2 (Canada); Cohen, Judith G.; Sesar, Branimir [Department of Physics and Astronomy, Caltech, Pasadena, CA (United States); Ripepi, Vincenzo [INAF-Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli (Italy); Derekas, Aliz [Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, H-1121 Budapest (Hungary); Moskalik, Pawel [Copernicus Astronomical Centre, ul.Bartycka 18, 00-716, Warsaw (Poland); Chadid, Merieme [Observatoire de la Cote d'Azur, Universite de Nice, Sophia-Antipolis, UMR 6525, Parc Valrose, F-06108 Nice Cedex 02 (France); Bruntt, Hans, E-mail: nemec@camosun.ca, E-mail: jmn@isr.bc.ca, E-mail: jlc@astro.caltech.edu, E-mail: bsesar@astro.caltech.edu, E-mail: ripepi@na.astro.it, E-mail: derekas@konkoly.hu, E-mail: pam@camk.edu.pl, E-mail: chadid@marseille.fr, E-mail: bruntt@phys.au.dk [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)

2013-08-20T23:59:59.000Z

33

UV-TO-FIR ANALYSIS OF SPITZER/IRAC SOURCES IN THE EXTENDED GROTH STRIP. II. PHOTOMETRIC REDSHIFTS, STELLAR MASSES, AND STAR FORMATION RATES  

SciTech Connect (OSTI)

Based on the ultraviolet to far-infrared photometry already compiled and presented in a companion paper (Paper I), we present a detailed spectral energy distribution (SED) analysis of nearly 80,000 IRAC 3.6 + 4.5 {mu}m selected galaxies in the Extended Groth Strip. We estimate photometric redshifts, stellar masses, and star formation rates (SFRs) separately for each galaxy in this large sample. The catalog includes 76,936 sources with [3.6] {<=} 23.75 (85% completeness level of the IRAC survey) over 0.48 deg{sup 2}. The typical photometric redshift accuracy is {Delta}z/(1 + z) = 0.034, with a catastrophic outlier fraction of just 2%. We quantify the systematics introduced by the use of different stellar population synthesis libraries and initial mass functions in the calculation of stellar masses. We find systematic offsets ranging from 0.1 to 0.4 dex, with a typical scatter of 0.3 dex. We also provide UV- and IR-based SFRs for all sample galaxies, based on several sets of dust emission templates and SFR indicators. We evaluate the systematic differences and goodness of the different SFR estimations using the deep FIDEL 70 {mu}m data available in the Extended Groth Strip. Typical random uncertainties of the IR-bases SFRs are a factor of two, with non-negligible systematic effects at z {approx}> 1.5 observed when only MIPS 24 {mu}m data are available. All data products (SEDs, postage stamps from imaging data, and different estimations of the photometric redshifts, stellar masses, and SFRs of each galaxy) described in this and the companion paper are publicly available, and they can be accessed through our the Web interface utility Rainbow-navigator.

Barro, G.; Perez-Gonzalez, P. G.; Gallego, J.; Villar, V.; Zamorano, J. [Departamento de Astrofisica, Facultad de CC. Fisicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Ashby, M. L. N. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Kajisawa, M.; Yamada, T. [Astronomical Institute, Tohoku University, Aramaki, Aoba, Sendai 9808578 (Japan); Miyazaki, S. [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan)

2011-04-01T23:59:59.000Z

34

Photoinduced phenomena and structural analysis associated with the spin state switching in the [Fe(II)  

E-Print Network [OSTI]

-Ecole Normale Supérieure de Lyon, Laboratoire de Chimie, UMR 5182, 46 allée d'Italie, F- 69364 Lyon Cédex 07. 5

Paris-Sud XI, Université de

35

Separation and concentration of lower alcohols from dilute aqueous solutions  

DOE Patents [OSTI]

A process for producing, from a dilute aqueous solution of a lower (C.sub.1 -C.sub.5) alcohol, a concentrated liquid solution of the alcohol in an aromatic organic solvent is disclosed. Most of the water is removed from the dilute aqueous solution of alcohol by chilling sufficiently to form ice crystals. Simultaneously, the remaining liquid is extracted at substantially the same low temperature with a liquid organic solvent that is substantially immiscible in aqueous liquids and has an affinity for the alcohol at that temperature, causing the alcohol to transfer to the organic phase. After separating the organic liquid from the ice crystals, the organic liquid can be distilled to enrich the concentration of alcohol therein. Ethanol so separated from water and concentrated in an organic solvent such as toluene is useful as an anti-knock additive for gasoline.

Moore, Raymond H. (Richland, WA); Eakin, David E. (Kennewick, WA); Baker, Eddie G. (Richland, WA); Hallen, Richard T. (Richland, WA)

1991-01-01T23:59:59.000Z

36

Groundwater and Terrestrial Water Storage,  

E-Print Network [OSTI]

4.9. NOAAs Accumulated Cyclone Energy (ACE) Index in theF ig . 4.23 (a) Accumulated Cyclone Energy (ACE) In- dex perone TY). The accumulated cyclone energy (ACE) in the WNP (

Rodell, M; Chambers, D P; Famiglietti, J S

2011-01-01T23:59:59.000Z

37

Aerosol Science and Technology, 41:202216, 2007 Copyright c American Association for Aerosol Research  

E-Print Network [OSTI]

processes, such as con- densation, coagulation, gas-to-particle conversion (Reid et al. 1998), and particle Aerosol size distribution is, along with particle refractive in- dex and shape, one of important

38

Lactoferrin inhibits dexamethasone-induced chondrocyte impairment from osteoarthritic cartilage through up-regulation of extracellular signal-regulated kinase 1/2 and suppression of FASL, FAS, and Caspase 3  

SciTech Connect (OSTI)

Highlights: Dex exerts dose-dependant inhibition of HACs viability and induction of apoptosis. Dex-induced impairment of chondrocytes was attenuated by rhLF. ERK and FASL/FAS signaling are involved in the effects of rhLF. OA patients with glucocorticoid-induced cartilage damage may benefit from treatment with rhLF. -- Abstract: Dexamethasone (Dex) is commonly used for osteoarthritis (OA) with excellent anti-inflammatory and analgesic effect. However, Dex also has many side effects following repeated use over prolonged periods mainly through increasing apoptosis and inhibiting proliferation. Lactoferrin (LF) exerts significantly anabolic effect on many cells and little is known about its effect on OA chondrocytes. Therefore, the aim of this study is to investigate whether LF can inhibit Dex-induced OA chondrocytes apoptosis and explore its possible molecular mechanism involved in. MTT assay was used to determine the optimal concentration of Dex and recombinant human LF (rhLF) on chondrocytes at different time and dose points. Chondrocytes were then stimulated with Dex in the absence or presence of optimal concentration of rhLF. Cell proliferation and viability were evaluated using MTT and LIVE/DEAD assay, respectively. Cell apoptosis was evaluated by multi-parameter apoptosis assay kit using both confocal microscopy and flow cytometry, respectively. The expression of extracellular signal-regulated kinase (ERK), FAS, FASL, and Caspase-3 (CASP3) at the mRNA and protein levels were examined by real-time polymerase chain reaction (PCR) and immunocytochemistry, respectively. The optimal concentration of Dex (25 ?g/ml) and rhLF (200 ?g/ml) were chosen for the following experiments. rhLF significantly reversed the detrimental effect of Dex on chondrocytes proliferation, viability, and apoptosis. In addition, rhLF significantly prevented Dex-induced down-regulation of ERK and up-regulation of FAS, FASL, and CASP3. These findings demonstrated that rhLF acts as an anabolic effect on chondrocytes through significantly reversing Dex-induced chondrocytes apoptosis. This study may contribute to further investigating the clinical application of LF on OA.

Tu, Yihui [Department of Orthopaedics, Yangpu District Central Hospital Affiliated to Tongji University School of Medicine, 450 Tengyue Road, Shanghai (China)] [Department of Orthopaedics, Yangpu District Central Hospital Affiliated to Tongji University School of Medicine, 450 Tengyue Road, Shanghai (China); Xue, Huaming [Department of Orthopaedics, Yangpu District Central Hospital Affiliated to Tongji University School of Medicine, 450 Tengyue Road, Shanghai (China) [Department of Orthopaedics, Yangpu District Central Hospital Affiliated to Tongji University School of Medicine, 450 Tengyue Road, Shanghai (China); Institute of Life Science, College of Medicine, Swansea University, Singleton Park (United Kingdom); Francis, Wendy [Institute of Life Science, College of Medicine, Swansea University, Singleton Park (United Kingdom)] [Institute of Life Science, College of Medicine, Swansea University, Singleton Park (United Kingdom); Davies, Andrew P. [Department of Orthopaedics and Trauma, Moriston Hospital, Swansea (United Kingdom)] [Department of Orthopaedics and Trauma, Moriston Hospital, Swansea (United Kingdom); Pallister, Ian; Kanamarlapudi, Venkateswarlu [Institute of Life Science, College of Medicine, Swansea University, Singleton Park (United Kingdom)] [Institute of Life Science, College of Medicine, Swansea University, Singleton Park (United Kingdom); Xia, Zhidao, E-mail: zhidao.xia@gmail.com [Institute of Life Science, College of Medicine, Swansea University, Singleton Park (United Kingdom)] [Institute of Life Science, College of Medicine, Swansea University, Singleton Park (United Kingdom)

2013-11-08T23:59:59.000Z

39

Xenon in Mercury-Manganese Stars  

E-Print Network [OSTI]

Previous studies of elemental abundances in Mercury-Manganese (HgMn) stars have occasionally reported the presence of lines of the ionized rare noble gas Xe II, especially in a few of the hottest stars with Teff ~ 13000--15000 K. A new study of this element has been undertaken using observations from Lick Observatory's Hamilton Echelle Spectrograph. In this work, the spectrum synthesis program UCLSYN has been used to undertake abundance analysis assuming LTE. We find that in the Smith & Dworetsky sample of HgMn stars, Xe is vastly over-abundant in 21 of 22 HgMn stars studied, by factors of 3.1--4.8 dex. There does not appear to be a significant correlation of Xe abundance with Teff. A comparison sample of normal late B stars shows no sign of Xe II lines that could be detected, consistent with the expected weakness of lines at normal abundance. The main reason for the previous lack of widespread detection in HgMn stars is probably due to the strongest lines being at longer wavelengths than the photographic blue. The lines used in this work were 4603.03A, 4844.33A and 5292.22A.

M. M. Dworetsky; J. L. Persaud; K. Patel

2008-01-16T23:59:59.000Z

40

VARIABLE STARS IN THE ULTRA-FAINT DWARF SPHEROIDAL GALAXY URSA MAJOR I  

SciTech Connect (OSTI)

We have performed the first study of the variable star population of Ursa Major I (UMa I), an ultra-faint dwarf satellite recently discovered around the Milky Way (MW) by the Sloan Digital Sky Survey. Combining time series observations in the B and V bands from four different telescopes, we have identified seven RR Lyrae stars in UMa I, of which five are fundamental-mode (RRab) and two are first-overtone pulsators (RRc). Our V, B - V color-magnitude diagram of UMa I reaches V {approx} 23 mag (at a signal-to-noise ratio of {approx}6) and shows features typical of a single old stellar population. The mean pulsation period of the RRab stars (P{sub ab}) = 0.628, {sigma} = 0.071 days (or (P{sub ab}) = 0.599, {sigma} = 0.032 days, if V4, the longest period and brightest variable, is discarded) and the position on the period-amplitude diagram suggest an Oosterhoff-intermediate classification for the galaxy. The RR Lyrae stars trace the galaxy horizontal branch (HB) at an average apparent magnitude of (V(RR)) = 20.43 {+-} 0.02 mag (average on six stars and discarding V4), giving in turn a distance modulus for UMa I of (m - M){sub 0} = 19.94 {+-} 0.13 mag, distance d = 97.3{sup +6.0}{sub -5.7} kpc, in the scale where the distance modulus of the Large Magellanic Cloud is 18.5 {+-} 0.1 mag. Isodensity contours of UMa I red giants and HB stars (including the RR Lyrae stars identified in this study) show that the galaxy has an S-shaped structure, which is likely caused by the tidal interaction with the MW. Photometric metallicities were derived for six of the UMa I RR Lyrae stars from the parameters of the Fourier decomposition of the V-band light curves, leading to an average metal abundance of [Fe/H] = -2.29 dex ({sigma} = 0.06 dex, average on six stars) on the Carretta et al. metallicity scale.

Garofalo, Alessia; Moretti, Maria Ida [Dipartimento di Astronomia, Universita di Bologna, Via Ranzani 1, I-40127 Bologna (Italy)] [Dipartimento di Astronomia, Universita di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Cusano, Felice; Clementini, Gisella [INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy)] [INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Ripepi, Vincenzo; Dall'Ora, Massimo; Coppola, Giuseppina; Musella, Ilaria; Marconi, Marcella, E-mail: alessia.garofalo@studio.unibo.it, E-mail: fcusano@na.astro.it, E-mail: gisella.clementini@oabo.inaf.it, E-mail: ripepi@na.astro.it, E-mail: dallora@na.astro.it, E-mail: imoretti@na.astro.it, E-mail: coppola@na.astro.it, E-mail: ilaria@na.astro.it, E-mail: marcella@na.astro.it [INAF-Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli (Italy)] [INAF-Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli (Italy)

2013-04-10T23:59:59.000Z

Note: This page contains sample records for the topic "antiknock in dex" 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

Dark Matter and Stellar Mass in the Luminous Regions of Disk Galaxies  

E-Print Network [OSTI]

We investigate the correlations among stellar mass (M_*), disk scale length (R_d), and rotation velocity at 2.2 disk scale lengths (V_2.2) for a sample of 81 disk-dominated galaxies (disk/total >= 0.9) selected from the SDSS. We measure V_2.2 from long-slit H-alpha rotation curves and infer M_* from galaxy i-band luminosities (L_i) and g-r colors. We find logarithmic slopes of 2.60+/-0.13 and 3.05+/-0.12 for the L_i-V_2.2 and M_*-V_2.2 relations, somewhat shallower than most previous studies, with intrinsic scatter of 0.13 dex and 0.16 dex. Our direct estimates of the total-to-stellar mass ratio within 2.2R_d, assuming a Kroupa IMF, yield a median ratio of 2.4 for M_*>10^10 Msun and 4.4 for M_*=10^9-10^10 Msun, with large scatter at a given M_* and R_d. The typical ratio of the rotation speed predicted for the stellar disk alone to the observed rotation speed at 2.2R_d is ~0.65. The distribution of R_d at fixed M_* is broad, but we find no correlation between disk size and the residual from the M_*-V_2.2 relation, implying that this relation is an approximately edge-on view of the disk galaxy fundamental plane. Independent of the assumed IMF, this result implies that stellar disks do not, on average, dominate the mass within 2.2R_d. We discuss our results in the context of infall models of disk formation in cold dark matter halos. A model with a disk-to-halo mass ratio m_d=0.05 provides a reasonable match to the R_d-M_* distribution for spin parameters \\lambda ranging from ~0.04-0.08, and it yields a reasonable match to the mean M_*-V_2.2 relation. A model with m_d=0.1 predicts overly strong correlations between disk size and M_*-V_2.2 residual. Explaining the wide range of halo-to-disk mass ratios within 2.2R_d requires significant scatter in m_d values, with systematically lower m_d for galaxies with lower $M_*$.

James Pizagno; Francisco Prada; David H. Weinberg; Hans-Walter Rix; Daniel Harbeck; Eva K. Grebel; Eric Bell; Jon Brinkmann; Jon Holtzman; Andrew West

2005-11-02T23:59:59.000Z

42

Oxygen enrichment in carbon-rich planetary nebulae  

E-Print Network [OSTI]

We study the relation between the chemical composition and the type of dust present in a group of 20 Galactic planetary nebulae (PNe) that have high quality optical and infrared spectra. The optical spectra are used, together with the best available ionization correction factors, to calculate the abundances of Ar, C, Cl, He, N, Ne, and O relative to H. The infrared spectra are used to classify the PNe in two groups depending on whether the observed dust features are representative of oxygen-rich or carbon-rich environments. The sample contains one object from the halo, eight from the bulge, and eleven from the local disc. We compare their chemical abundances with nucleosynthesis model predictions and with the ones obtained in seven Galactic H II regions of the solar neighbourhood. We find evidence of O enrichment (by $\\sim$ 0.3 dex) in all but one of the PNe with carbon-rich dust (CRD). Our analysis shows that Ar, and especially Cl, are the best metallicity indicators of the progenitors of PNe. There is a tig...

Delgado-Inglada, Gloria; Peimbert, Manuel; Stasi?ska, Gra?yna; Morisset, Christophe

2015-01-01T23:59:59.000Z

43

Ca isotopic anomaly in the atmospheres of Ap stars  

E-Print Network [OSTI]

We present results of the Ca stratification analysis in the atmospheres of 21 magnetic chemically peculiar (Ap) stars. This analysis was based on the spectral observations carried out with the UVES spectrograph attached to the 8-m VLT telescope. Ca was found to be strongly stratified in all stars with different effective temperatures and magnetic field strengths. This element is overabundant by 1-1.5 dex below logtau_5000~-1 and strongly depleted above logtau_5000=-1.5. Based on the overall Ca abundance distributions, we modelled a profile of the IR-triplet Ca II 8498 line. It shows a significant contribution of the heavy isotopes 46Ca and 48Ca, which represent less than 1% of the solar Ca isotopic mixture. In Ap stars with the relatively small surface magnetic fields (Ca isotope is concentrated close to the photosphere, while the heavy isotopes are pushed towards the outer layers. Isotopic separation disappears in the atmospheres of stars with magnetic fields above 6-7 kG. The observed overall Ca stratification and isotopic anomalies may be explained by a combined action of the radiatively-driven diffusion and the light-induced drift.

T. Ryabchikova; O. Kochukhov; S. Bagnulo

2007-03-13T23:59:59.000Z

44

Stellar substructures in the solar neighbourhood IV. Kinematic Group 1 in the Geneva-Copenhagen survey  

E-Print Network [OSTI]

We determine detailed elemental abundances in stars belonging to the so-called Group 1 of the Geneva-Copenhagen survey (GCS) and compare the chemical composition with the Galactic thin- and thick-disc stars, with the GCS Group 2 and Group 3 stars, as well as with several kinematic streams of similar metallicities. The aim is to search for chemical signatures that might give information about the formation history of this kinematic group of stars. High-resolution spectra were obtained with the Fibre-fed Echelle Spectrograph (FIES) spectrograph at the Nordic Optical Telescope, La Palma, and were analysed with a differential model atmosphere method. Comparison stars were observed and analysed with the same method. The average value of [Fe/H] for the 37 stars of Group 1 is -0.20 +- 0.14 dex. Investigated Group 1 stars can be separated into three age subgroups. Along with the main 8- and 12-Gyr-old populations, a subgroup of stars younger than 5 Gyr can be separated as well. Abundances of oxygen, alpha-elements, a...

enovien?, R; Nordstrm, B; Stonkut?, E; Barisevi?ius, G

2015-01-01T23:59:59.000Z

45

Light Element Abundance Patterns in the Orion Association: I) HST Observations of Boron in G-dwarfs  

E-Print Network [OSTI]

The boron abundances for two young solar-type members of the Orion association, BD -6 1250 and HD 294297, are derived from HST STIS spectra of the B I transition at 2496.771 A. The best-fit boron abundances for the target stars are 0.13 and 0.44 dex lower than the solar meteoritic value of log e(B)=2.78. An anticorrelation of boron and oxygen is found for Orion when these results are added to previous abundances obtained for 4 B-type stars and the G-type star BD -5 1317. An analysis of the uncertainties in the abundance calculations indicates that the observed anticorrelation is probably real. The B versus O relation observed in the Orion association does not follow the positive correlation of boron versus oxygen which is observed for the field stars with roughly solar metallicity. The observed anticorrelation can be accounted for by a simple model in which two poorly mixed components of gas (supernova ejecta and boron-enriched ambient medium) contribute to the new stars that form within the lifetime of the association. This model predicts an anticorrelation for Be as well, at least as strong as for boron.

K. Cunha; V. Smith; E. Parizot; D. Lambert

2000-05-22T23:59:59.000Z

46

Oxygen abundance in the Sloan Digital Sky Survey  

E-Print Network [OSTI]

We present two samples of $\\hii$ galaxies from the Sloan Digital Sky Survey (SDSS) spectroscopic observations data release 3. The electron temperatures($T_e$) of 225 galaxies are calculated with the photoionized $\\hii$ model and $T_e$ of 3997 galaxies are calculated with an empirical method. The oxygen abundances from the $T_e$ methods of the two samples are determined reliably. The oxygen abundances from a strong line metallicity indicator, such as $R_{23}$, $P$, $N2$, and $O3N2$, are also calculated. We compared oxygen abundances of $\\hii$ galaxies obtained with the $T_e$ method, $R_{23}$ method, $P$ method, $N2$ method, and $O3N2$method. The oxygen abundances derived with the $T_e$ method are systematically lower by $\\sim$0.2 dex than those derived with the $R_{23}$ method, consistent with previous studies based on $\\hii$ region samples. No clear offset for oxygen abundance was found between $T_e$ metallicity and $P$, $N2$ and $O3N2$ metallicity. When we studied the relation between N/O and O/H, we found that in the metallicity regime of $\\zoh > 7.95$, the large scatter of the relation can be explained by the contribution of small mass stars to the production of nitrogen. In the high metallicity regime, $\\zoh > 8.2$, nitrogen is primarily a secondary element produced by stars of all masses.

F. Shi; X. Kong; F. Z. Cheng

2006-03-10T23:59:59.000Z

47

Oxygen abundances in G- and F-type stars from HARPS  

E-Print Network [OSTI]

We present a detailed and uniform study of oxygen abundance from two different oxygen lines at 6158$\\AA$ and 6300$\\AA$ in a large sample of solar-type stars. The results are used to check the behaviour of these spectral lines as oxygen abundance indicators and to study the evolution of oxygen in thick and thin disk populations of the Galaxy. Equivalent width measurements were carried out for the [OI]~6158$\\AA$ and OI~6300$\\AA$ lines. LTE abundances were obtained from these two lines in 610 and 535 stars, respectively. We were able to measure oxygen abundance from both indicators in 447 stars, enabling us, for the first time, to compare them in a uniform way. Careful error analysis has been performed. We found that oxygen abundances derived from the 6158$\\AA$ and 6300$\\AA$ lines agree to within 0.1dex in 58\\% of the stars in our sample, and this result improves for higher signal-to-noise values. We confirm an oxygen enhancement in stars of the thick disk, as has also been seen for other $\\alpha$-elements. The ...

de Lis, S Bertran; Adibekyan, V Zh; Santos, N C; Sousa, S G

2015-01-01T23:59:59.000Z

48

Analysis of RGU Photometry in Selected Area 51  

E-Print Network [OSTI]

A low-latitude anticenter field (l=189, b=+21) is investigated by using the full calibration tools of RGU photometry. The observed RGU data are reduced to the standard system and the separation of dwarfs and evolved stars is carried out by an empirical method. Stars are categorized into three metallicity classes, i.e. -0.25<[M/H]<=+0.50, -1.00<[M/H]<=-0.25, and [M/H]<=-1.00$ dex, and their absolute magnitudes are determined by the corresponding colour-magnitude diagrams. The unusually large scattering in the two-colour diagrams is reduced by excluding 153 extra-galactic objects, identifying them compared with the charts of Basel Astronomical Institute and University of Minnesota, and by the criterion and algorithm of Gaidos et al. (1993). The local logarithmic space density for giants, D(0)=6.75, lies within the local densities of Gliese (1969) and Gliese & Jahreiss (1992). The local luminosity function for the absolute magnitude interval 3

S. Bilir; S. Karaali; R. Buser

2004-07-02T23:59:59.000Z

49

Fe and Al Abundances for 180 Red Giants in the Globular Cluster Omega Centauri (NGC 5139)  

E-Print Network [OSTI]

We present radial velocities, Fe, and Al abundances for 180 red giant branch (RGB) stars in the Galactic globular cluster Omega Centauri ($\\omega$ Cen). The majority of our data lie in the range 11.0$Al/Fe] ratios exhibit large star--to--star scatter for all populations, with the more than 1.0 dex range of [Al/Fe] decreasing for stars more metal--rich than [Fe/H]$\\sim$--1.4. The minimum [Al/Fe] abundance observed for all metallicity populations is [Al/Fe]$\\sim$+0.15. The maximum abundance of log $\\epsilon$(Al) is reached for stars with [Fe/H]$\\sim$--1.4 and does not increase further with stellar metallicity. We interpret these results as evidence for type II SNe providing the minimum [Al/Fe] ratio and a mass spectrum of intermediate mass asymptotic giant branch stars causing the majority of the [Al/Fe] scatter. These results seem to fit in the adopted scheme that star formation occurred in $\\omega$ Cen over $>$1 Gyr.

Christian I. Johnson; Catherine A. Pilachowski; Jennifer Simmerer; Dustin Schwenk

2008-04-16T23:59:59.000Z

50

A New Definition for the Ca4227 Feature: Is Calcium Really Underabundant in Early-type Galaxies?  

E-Print Network [OSTI]

We have investigated the abundance of calcium in early-type galaxies by measuring the strength of the Ca I 4227 absorption line in their integrated spectra. The database used is the large sample of early-type galaxy integrated spectra in Caldwell, Rose, & Concannon (2003). We have measured Ca abundances from the Ca I 4227 feature both by using the Lick Ca4227 index and also by defining a new index, Ca4227_r, that avoids the CN4216 molecular band in the continuum on the blueward side of the line. With the new index definition we measure Ca abundances that are systematically ~0.3 dex higher than with the Lick Ca4227 index. The result is that with the new index definition we obtain higher [Ca/Fe] abundances in early-type galaxies which are more consistent with their well known [Mg/Fe] over-abundances. Hence, we suggest that Ca might be slightly enhanced, relative to Fe, in early-type galaxies.

L. C. Prochaska; James A. Rose; Ricardo P. Schiavon

2005-09-26T23:59:59.000Z

51

Iron and s-elements abundance variations in NGC5286: comparison with anomalous globular clusters and Milky Way satellites  

E-Print Network [OSTI]

We present a high resolution spectroscopic analysis of 62 red giants in the Milky Way globular cluster NGC5286. We have determined abundances of representative light proton-capture, alpha, Fe-peak and neutron-capture element groups, and combined them with photometry of multiple sequences observed along the colour-magnitude diagram. Our principal results are: (i) a broad, bimodal distribution in s-process element abundance ratios, with two main groups, the s-poor and s-rich groups; (ii) substantial star-to-star Fe variations, with the s-rich stars having higher Fe, e.g. _s-rich - _s-poor ~ 0.2~dex; and (iii) the presence of O-Na-Al (anti-)correlations in both stellar groups. We have defined a new photometric index, c_{BVI}=(B-V)-(V-I), to maximise the separation in the colour-magnitude diagram between the two stellar groups with different Fe and s-element content, and this index is not significantly affected by variations in light elements (such as the O-Na anticorrelation). The variations in the overall metal...

Marino, A F; Karakas, A I; Casagrande, L; Yong, D; Shingles, L; Da Costa, G; Norris, J E; Stetson, P B; Lind, K; Asplund, M; Collet, R; Jerjen, H; Sbordone, L; Aparicio, A; Cassisi, S

2015-01-01T23:59:59.000Z

52

Insights from the Outskirts: Chemical and Dynamical Properties in the outer Parts of the Fornax Dwarf Spheroidal Galaxy  

E-Print Network [OSTI]

We present radial velocities and [Fe/H] abundances for 340 stars in the Fornax dwarf spheroidal from R~16,000 spectra. The targets have been obtained in the outer parts of the galaxy, a region which has been poorly studied before. Our sample shows a wide range in [Fe/H], between -0.5 and -3.0 dex, in which we detect three subgroups. Removal of stars belonging to the most metal-rich population produces a truncated metallicity distribution function that is identical to Sculptor, indicating that these systems have shared a similar early evolution, only that Fornax experienced a late, intense period of star formation (SF). The derived age-metallicity relation shows a fast increase in [Fe/H] at early ages, after which the enrichment flattens significantly for stars younger than ~8 Gyr. Additionally, the data indicate a strong population of stars around 4 Gyr, followed by a second rapid enrichment in [Fe/H]. A leaky-box chemical enrichment model generally matches the observed relation but does not predict a signifi...

Hendricks, Benjamin; Walker, Matthew; Johnson, Christian I; Penarrubia, Jorge; Gilmore, Gerard

2014-01-01T23:59:59.000Z

53

A COLD MILKY WAY STELLAR STREAM IN THE DIRECTION OF TRIANGULUM  

SciTech Connect (OSTI)

We present evidence for a new Milky Way stellar tidal stream in the direction of the Andromeda and Triangulum (M31 and M33) galaxies. Using a matched-filter technique, we search the Sloan Digital Sky Survey Data Release 8 by creating stellar density maps which probe the Milky Way halo at distances between 8 and 40 kpc. A visual search of these maps recovers all of the major known stellar streams, as well as a new stream in the direction of M31/M33 that we name the Triangulum stream. The stream spans 0.{sup 0}2 by 12 Degree-Sign on the sky, or 75 pc by 5.5 kpc in physical units with a best-fitting distance of 26 {+-} 4 kpc. The width of the stream is consistent with being the tidal remnant of a globular cluster. A color-magnitude diagram of the stream region shows an overdensity which, if identified as a main-sequence turnoff, corresponds to an old ({approx}12 Gyr) and metal-poor ([Fe/H] {approx}-1.0 dex) stellar population. Future kinematic studies of this and similar cold streams will provide tight constraints on the shape of the Galactic gravitational potential.

Bonaca, Ana; Geha, Marla; Kallivayalil, Nitya, E-mail: ana.bonaca@yale.edu [Department of Astronomy, Yale University, New Haven, CT 06511 (United States)

2012-11-20T23:59:59.000Z

54

Energy transport, overshoot, and mixing in the atmospheres of M-type main- and pre-main-sequence objects  

E-Print Network [OSTI]

We constructed hydrodynamical model atmospheres for mid M-type main-, as well as pre-main-sequence (PMS) objects. Despite the complex chemistry encountered in these cool atmospheres a reasonably accurate representation of the radiative transfer is possible, even in the context of time-dependent and three-dimensional models. The models provide detailed information about the morphology of M-type granulation and statistical properties of the convective surface flows. In particular, we determined the efficiency of the convective energy transport, and the efficiency of mixing by convective overshoot. The convective transport efficiency was expressed in terms of an equivalent mixing-length parameter alpha in the formulation of mixing-length theory (MLT) given by Mihalas (1978). Alpha amounts to values around 2 for matching the entropy of the deep, adiabatically stratified regions of the convective envelope, and lies between 2.5 and 3.0 for matching the thermal structure of the deep photosphere. For current spectral analysis of PMS objects this implies that MLT models based on alpha=2.0 overestimate the effective temperature by 100 K and surface gravities by 0.25 dex. The average thermal structure of the formally convectively stable layers is little affected by convective overshoot and wave heating, i.e., stays close to radiative equilibrium conditions. Our models suggest that the rate of mixing by convective overshoot declines exponentially with geometrical distance to the Schwarzschild stability boundary. It increases at given effective temperature with decreasing gravitational acceleration.

H. -G. Ludwig; F. Allard; P. H. Hauschildt

2006-08-12T23:59:59.000Z

55

The High-Mass Stellar Initial Mass Function in M31 Clusters  

E-Print Network [OSTI]

We have undertaken the largest systematic study of the high-mass stellar initial mass function (IMF) to date using the optical color-magnitude diagrams (CMDs) of 85 resolved, young (4 Myr 2 Msun. For the ensemble of clusters, the distribution of stellar MF slopes is best described by $\\Gamma=+1.45^{+0.03}_{-0.06}$ with a very small intrinsic scatter. The data also imply no significant dependencies of the MF slope on cluster age, mass, and size, providing direct observational evidence that the measured MF represents the IMF. This analysis implies that the high-mass IMF slope in M31 clusters is universal with a slope ($\\Gamma=+1.45^{+0.03}_{-0.06}$) that is steeper than the canonical Kroupa (+1.30) and Salpeter (+1.35) values. Using our inference model on select Milky Way (MW) and LMC high-mass IMF studies from the literature, we find $\\Gamma_{\\rm MW} \\sim+1.15\\pm0.1$ and $\\Gamma_{\\rm LMC} \\sim+1.3\\pm0.1$, both with intrinsic scatter of ~0.3-0.4 dex. Thus, while the high-mass IMF in the Local Group may be unive...

Weisz, Daniel R; Foreman-Mackey, Daniel; Dolphin, Andrew E; Beerman, Lori C; Williams, Benjamin F; Dalcanton, Julianne J; Rix, Hans-Walter; Hogg, David W; Fouesneau, Morgan; Johnson, Benjamin D; Bell, Eric F; Boyer, Martha L; Gouliermis, Dimitrios; Guhathakurta, Puragra; Kalirai, Jason S; Lewis, Alexia R; Seth, Anil C; Skillman, Evan D

2015-01-01T23:59:59.000Z

56

The Star Formation Histories of Local Group Dwarf Galaxies III. Characterizing Quenching in Low-Mass Galaxies  

E-Print Network [OSTI]

We explore the quenching of low-mass galaxies (10^4 < Mstar < 10^8 Msun) as a function of lookback time using the star formation histories (SFHs) of 38 Local Group dwarf galaxies. The SFHs were derived from analyzing color-magnitude diagrams of resolved stellar populations in archival Hubble Space Telescope/Wide Field Planetary Camera 2 imaging. We find: (1) Lower mass galaxies quench earlier than higher mass galaxies; (2) Inside of virial radius there is no correlation between a satellite's current proximity to a massive host and its quenching epoch; (3) There are hints of systematic differences in quenching times of M31 and Milky Way (MW) satellites, although the sample sample size and uncertainties in the SFHs of M31 dwarfs prohibit definitive conclusions. Combined with literature results, we qualitatively consider the redshift evolution (z=0-1) of the quenched galaxy fraction over ~7 dex in stellar mass (10^4 < Mstar < 10^11.5 Msun). The quenched fraction of all galaxies generally increases to...

Weisz, Daniel R; Skillman, Evan D; Holtzman, Jon; Gilbert, Karoline M; Dalcanton, Julianne J; Williams, Benjamin F

2015-01-01T23:59:59.000Z

57

Three-dimensional hydrodynamical CO5BOLD model atmospheres of red giant stars. IV. Oxygen diagnostics in extremely metal-poor red giants with infrared OH lines  

E-Print Network [OSTI]

Context. Although oxygen is an important tracer of Galactic chemical evolution, measurements of its abundance in the atmospheres of the oldest Galactic stars are still scarce and rather imprecise. At the lowest end of the metallicity scale, oxygen can only be measured in giant stars and in most of cases such measurements rely on a single forbidden [O I] 630 nm line that is very weak and frequently blended with telluric lines. Although molecular OH lines located in the ultraviolet and infrared could also be used for the diagnostics, oxygen abundances obtained from the OH lines and the [O I] 630 nm line are usually discrepant to a level of ~0.3-0.4 dex. Aims. We study the influence of convection on the formation of the infrared (IR) OH lines and the forbidden [O I] 630 nm line in the atmospheres of extremely metal-poor (EMP) red giant stars. Methods. We used high-resolution and high signal-to-noise ratio spectra of four EMP red giant stars obtained with the VLT CRIRES spectrograph. For each EMP star, 4-14 IR OH...

Dobrovolskas, V; Bonifacio, P; Caffau, E; Ludwig, H -G; Steffen, M; Spite, M

2015-01-01T23:59:59.000Z

58

Color-Magnitude Diagram Constraints on the Metallicities, Ages, and Star Formation History of the Stellar Populations in the Carina Dwarf Spheroidal Galaxy  

E-Print Network [OSTI]

Victoria-Regina isochrones for $-0.4 \\le$ [alpha/Fe] $\\le +0.4$ and a wide range in [Fe/H], along with complementary zero-age horizontal branch (ZAHB) loci, have been applied to the color-magnitude diagram (CMD) of Carina. The color transformations that we have used have been "calibrated" so that isochrones provide excellent fits to the $[(B-V)_0,\\,M_V]$-diagrams of M3 and M92, when well supported estimates of the globular cluster (GC) reddenings and metallicities are assumed. The adopted distance moduli, for both the GCs and Carina, are based on our ZAHB models, which are able to reproduce the old HB component (as well as the luminosity of the HB clump) of the dwarf spheroidal galaxy quite well --- even if it spans a range in [Fe/H] of ~ 1.5 dex, provided that [alpha/Fe] varies with [Fe/H] in approximately the way that has been derived spectroscopically. Ages derived here agree reasonably well with those found previously for the old and intermediate-age turnoff stars, as well as for the period of negligible ...

VandenBerg, Don A; Brown, Thomas M

2015-01-01T23:59:59.000Z

59

Keck-I MOSFIRE spectroscopy of compact star-forming galaxies at z$\\gtrsim$2: High velocity dispersions in progenitors of compact quiescent galaxies  

E-Print Network [OSTI]

We present Keck-I MOSFIRE near-infrared spectroscopy for a sample of 13 compact star-forming galaxies (SFGs) at redshift $2\\leq z \\leq2.5$ with star formation rates of SFR$\\sim$100M$_{\\odot}$ y$^{-1}$ and masses of log(M/M$_{\\odot}$)$\\sim10.8$. Their high integrated gas velocity dispersions of $\\sigma_{\\rm{int}}$=230$^{+40}_{-30}$ km s$^{-1}$, as measured from emission lines of H$_{\\alpha}$ and [OIII], and the resultant M$_{\\star}-\\sigma_{\\rm{int}}$ relation and M$_{\\star}$$-$M$_{\\rm{dyn}}$ all match well to those of compact quiescent galaxies at $z\\sim2$, as measured from stellar absorption lines. Since log(M$_{\\star}$/M$_{\\rm{dyn}}$)$=-0.06\\pm0.2$ dex, these compact SFGs appear to be dynamically relaxed and more evolved, i.e., more depleted in gas and dark matter ($infusion of external gas, depletion timescales are short, less than $\\sim$300 Myr. This discovery adds another link to our new dynamical chain of evidence...

Barro, G; Koo, D C; Dekel, A; Kassin, S A; Kocevski, D D; Faber, S M; van der Wel, A; Guo, Y; Perez-Gonzalez, P G; Toloba, E; Fang, J J; Pacifici, C; Simons, R; Campbell, R D; Ceverino, D; Finkelstein, S L; Goodrich, B; Kassis, M; Koekemoer, A M; Konidaris, N P; Livermore, R C; Lyke, J E; Mobasher, B; Nayyeri, H; Peth, M; Primack, J R; Rizzi, L; Somerville, R S; Wirth, G D; Zolotov, A

2014-01-01T23:59:59.000Z

60

Rare-earth elements in the atmosphere of the magnetic chemically peculiar star HD 144897. New classification of the Nd III spectrum  

E-Print Network [OSTI]

We have obtained a UVES spectrum of a slowly rotating strongly magnetic Ap star, HD 144897, that exhibits very large overabundances of rare-earth elements. Here we present a detailed spectral analysis of this object, also taking into account effects of non-uniform vertical distribution (stratification) of chemical elements. We have determined the photospheric abundances of 40 ions. For seven elements (Mg, Si, Ca, Ti, Cr, Mn, Fe), we have obtained a stratification model that allow us to produce a satisfactory fit to the observed profiles of spectral lines of various strength. REEs abundances, that for the first time in the literature have been determined from the lines of the first and second ions, have been found typically four dex larger than solar abundances. Our analysis of REE spectral lines provide a strong support to the laboratory line classification and determination of the atomic parameters. The only remarkable exception is Nd III, for which spectral synthesis was found to be inconsistent with the observations. We have therefore performed a revision of the Nd III classification. We have confirmed the energies for 11 out of 24 odd energy levels classified previously, and we have derived the energies for additional 24 levels of Nd III, thereby increasing substantially the number of classified Nd III lines with corrected wavelengths and atomic parameters.

T. Ryabchikova; A. Ryabtsev; O. Kochukhov; S. Bagnulo

2006-04-26T23:59:59.000Z

Note: This page contains sample records for the topic "antiknock in dex" from the National Library of EnergyBeta (NLEBeta).
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61

Rare-earth elements in the atmosphere of the magnetic chemically peculiar star HD 144897. New classification of the Nd III spectrum  

E-Print Network [OSTI]

We have obtained a UVES spectrum of a slowly rotating strongly magnetic Ap star, HD 144897, that exhibits very large overabundances of rare-earth elements. Here we present a detailed spectral analysis of this object, also taking into account effects of non-uniform vertical distribution (stratification) of chemical elements. We have determined the photospheric abundances of 40 ions. For seven elements (Mg, Si, Ca, Ti, Cr, Mn, Fe), we have obtained a stratification model that allow us to produce a satisfactory fit to the observed profiles of spectral lines of various strength. REEs abundances, that for the first time in the literature have been determined from the lines of the first and second ions, have been found typically four dex larger than solar abundances. Our analysis of REE spectral lines provide a strong support to the laboratory line classification and determination of the atomic parameters. The only remarkable exception is Nd III, for which spectral synthesis was found to be inconsistent with the ob...

Ryabchikova, T A; Kochukhov, O; Ryabtsov, A V

2006-01-01T23:59:59.000Z

62

Experimental Investigation of Spark-Ignited Combustion with High-Octane Biofuels and EGR. 2. Fuel and EGR Effects on Knock-Limited Load and Speed  

SciTech Connect (OSTI)

The present study experimentally investigates spark-ignited combustion with 87 AKI E0 gasoline in its neat form and in midlevel alcohol gasoline blends with 24% vol/vol isobutanol gasoline (IB24) and 30% vol/vol ethanol gasoline (E30). A single-cylinder research engine is used with an 11.85:1 compression ratio, hydraulically actuated valves, laboratory intake air, and was capable of external exhaust gas recirculation (EGR). Experiments were conducted with all fuels to full-load conditions with = 1, using both 0% and 15% external-cooled EGR. Higher octane number biofuel blends exhibited increased stoichiometric torque capability at this compression ratio, where the unique properties of ethanol enabled a doubling of the stoichiometric torque capability with E30 as compared to that of 87AKI, up to 20 bar IMEPg (indicating mean effective pressure gross) at = 1. The results demonstrate that for all fuels, EGR is a key enabler for increasing engine efficiency but is less useful for knock mitigation with E30 than for 87AKI gasoline or IB24. Under knocking conditions, 15% EGR is found to offer 1 CA of CA50 timing advance with E30, whereas up to 5 CA of CA50 advance is possible with knock-limited 87AKI gasoline. Compared to 87AKI, both E30 and IB24 are found to have reduced adiabatic flame temperature and shorter combustion durations, which reduce knocking propensity beyond that indicated by the octane number. However, E30+0% EGR is found to exhibit the better antiknock properties than either 87AKI+15% EGR or IB24+15% EGR, expanding the knock limited operating range and engine stoichiometric torque capability at high compression ratio. Furthermore, the fuel sensitivity (S) of E30 was attributed to reduced speed sensitivity of E30, expanding the low-speed stoichiometric torque capability at high compression ratio. The results illustrate that intermediate alcohol gasoline blends exhibit exceptional antiknock properties and performance beyond that indicated by the octane number tests, particularly E30.

Splitter, Derek A [ORNL] [ORNL; Szybist, James P [ORNL] [ORNL

2013-01-01T23:59:59.000Z

63

Chemical Evolution of Odd Elements in an Inhomogeneous Early Galaxy  

E-Print Network [OSTI]

We investigate the chemical evolution of odd-numbered elements such as sodium (Na) and aluminum (Al) during the early epochs of the Galactic halo with the use of a model that reproduces the observed box-shaped distribution of extremely metal-poor stars in the [Na, Al/Mg] versus [Mg/H] plane. Our model is constructed under the assumptions that those stars retain the elemental abundance patterns produced by individual Type II supernovae (SNe), and that the yields of the odd elements depend on the initial metallicity, z, of their SN progenitors. As a result, recent abundance determinations that clarify how the [Na, Al/Mg] ratios of field stars have evolved to the solar values enable us to deduce how the yields of these odd elements depend on z. The observed trends in these abundances, in particular the very large scatter (over 1 dex in [Al/Mg]) requires that the Al yield scales as m_Al proportional to z^0.6 for [Mg/H]-1.8. It is found that the predicted frequency distribution of stars in the [Na/Mg] versus [Mg/H] diagram is very sensitive to the assumed form of the primordial IMF, and that its slope is steeper than the Salpeter IMF. The necessity to match the observed abundance patterns of odd elements and the frequency distribution of extremely metal-poor stars should provide useful constraints on nucleosynthesis calculations of metal-free massive stars as well as on theories of their formation.

Takuji Tsujimoto; Toshikazu Shigeyama; Yuzuru Yoshii

2001-09-20T23:59:59.000Z

64

A SPECTROSCOPIC CATALOG OF THE BRIGHTEST (J < 9) M DWARFS IN THE NORTHERN SKY{sup ,}  

SciTech Connect (OSTI)

We present a spectroscopic catalog of the 1564 brightest (J < 9) M dwarf candidates in the northern sky, as selected from the SUPERBLINK proper motion catalog. Observations confirm 1408 of the candidates to be late-K and M dwarfs with spectral subtypes K7-M6. From the low ({mu} > 40 mas yr{sup -1}) proper motion limit and high level of completeness of the SUPERBLINK catalog in that magnitude range, we estimate that our spectroscopic census most likely includes >90% of all existing, northern-sky M dwarfs with apparent magnitude J < 9. Only 682 stars in our sample are listed in the Third Catalog of Nearby Stars (CNS3); most others are relative unknowns and have spectroscopic data presented here for the first time. Spectral subtypes are assigned based on spectral index measurements of CaH and TiO molecular bands; a comparison of spectra from the same stars obtained at different observatories, however, reveals that spectral band index measurements are dependent on spectral resolution, spectrophotometric calibration, and other instrumental factors. As a result, we find that a consistent classification scheme requires that spectral indices be calibrated and corrected for each observatory/instrument used. After systematic corrections and a recalibration of the subtype-index relationships for the CaH2, CaH3, TiO5, and TiO6 spectral indices, we find that we can consistently and reliably classify all our stars to a half-subtype precision. The use of corrected spectral indices further requires us to recalibrate the {zeta} parameter, a metallicity indicator based on the ratio of TiO and CaH optical bandheads. However, we find that our {zeta} values are not sensitive enough to diagnose metallicity variations in dwarfs of subtypes M2 and earlier ({+-}0.5 dex accuracy) and are only marginally useful at later M3-M5 subtypes ({+-}0.2 dex accuracy). Fits of our spectra to the Phoenix atmospheric model grid are used to estimate effective temperatures. These suggest the existence of a plateau in the M1-M3 subtype range, in agreement with model fits of infrared spectra but at odds with photometric determinations of T{sub eff}. Existing geometric parallax measurements are extracted from the literature for 624 stars, and are used to determine spectroscopic and photometric distances for all the other stars. Active dwarfs are identified from measurements of H{alpha} equivalent widths, and we find a strong correlation between H{alpha} emission in M dwarfs and detected X-ray emission from ROSAT and/or a large UV excess in the GALEX point source catalog. We combine proper motion data and photometric distances to evaluate the (U, V, W) distribution in velocity space, which is found to correlate tightly with the velocity distribution of G dwarfs in the solar neighborhood. However, active stars show a smaller dispersion in their space velocities, which is consistent with those stars being younger on average. Our catalog will be most useful to guide the selection of the best M dwarf targets for exoplanet searches, in particular those using high-precision radial velocity measurements.

Lepine, Sebastien; Wilde, Matthew; Rojas-Ayala, Barbara; Cruz, Kelle L. [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States); Hilton, Eric J.; Mann, Andrew W. [Institute for Astrophysics, University of Hawaii, Honolulu, HI 96822 (United States); Gaidos, Eric, E-mail: lepine@amnh.org, E-mail: brojas-ayala@amnh.org, E-mail: mwilde@amnh.org, E-mail: mshara@amnh.org, E-mail: hilton@ifa.hawaii.edu, E-mail: amann@ifa.hawaii.edu, E-mail: gaidos@hawaii.edu, E-mail: kellecruz@gmail.com [Department of Geology and Geophysics, University of Hawaii, 1680 East-West Road, Honolulu, HI 96822 (United States)

2013-04-15T23:59:59.000Z

65

Origin of the Metallicity Dependence of Exoplanet Host Stars in the Protoplanetary Disk Mass Distribution  

E-Print Network [OSTI]

The probability of a star hosting a planet that is detectable in radial velocity surveys increases Ppl(Z) oc 10^2Z, where Z is metallicity. Core accretion models reproduce this trend, since the protoplanetary disk of a high metallicity star has a high density of solids and so forms cores which accrete gas before the primordial gas disk dissipates. This paper considers the origin of the form of Ppl(Z). We introduce a simple model in which detectable planets form when the mass of solids in the protoplanetary disk, Ms, exceeds a critical value. In this model the form of Ppl(Z) is a direct reflection of the distribution of protoplanetary disk masses, Mg, and the observed Ppl(Z) is reproduced if P(Mg>Mg') oc 1/Mg'^2. We argue that a protoplanetary disk's sub-mm dust mass is a pristine indicator of the mass available for planet-building and find the observed sub-mm disk mass distribution is consistent with the observed Ppl(Z) if Ms>0.5M_J is required to form detectable planets. Any planet formation model which imposes a critical solid mass for planet formation would reproduce the observed Ppl(Z), and core accretion models are empirically consistent with a threshold criterion. We identify 7 protoplanetary disks which, by rigid application of this criterion, would be expected to form detectable planets. A testable prediction is that Ppl(Z) should flatten both for Z>0.5dex and as more distant and lower mass planets are discovered. Further, combining this model with one in which the evolution of a star's debris disk is also influenced by the solid mass in its protoplanetary disk, results in the prediction that debris disks detected around stars with planets should be more infrared luminous than those around stars without planets in tentative agreement with recent observations.

M. C. Wyatt; C. J. Clarke; J. S. Greaves

2007-07-18T23:59:59.000Z

66

The Connection between Galaxies and Dark Matter Structures in the Local Universe  

SciTech Connect (OSTI)

We provide new constraints on the connection between galaxies in the local Universe, identified by the Sloan Digital Sky Survey (SDSS), and dark matter halos and their constituent substructures in the {Lambda}CDM model using WMAP7 cosmological parameters. Predictions for the abundance and clustering properties of dark matter halos, and the relationship between dark matter hosts and substructures, are based on a high-resolution cosmological simulation, the Bolshoi simulation. We associate galaxies with dark matter halos and subhalos using subhalo abundance matching, and perform a comprehensive analysis which investigates the underlying assumptions of this technique including (a) which halo property is most closely associated with galaxy stellar masses and luminosities, (b) how much scatter is in this relationship, and (c) how much subhalos can be stripped before their galaxies are destroyed. The models are jointly constrained by new measurements of the projected two-point galaxy clustering and the observed conditional stellar mass function of galaxies in groups. We find that an abundance matching model that associates galaxies with the peak circular velocity of their halos is in good agreement with the data, when scatter of 0.20 {+-} 0.03 dex in stellar mass at a given peak velocity is included. This confirms the theoretical expectation that the stellar mass of galaxies is tightly correlated with the potential wells of their dark matter halos before they are impacted by larger structures. The data put tight constraints on the satellite fraction of galaxies as a function of galaxy stellar mass and on the scatter between halo and galaxy properties, and rule out several alternative abundance matching models that have been considered. This will yield important constraints for galaxy formation models, and also provides encouraging indications that the galaxy - halo connection can be modeled with sufficient fidelity for future precision studies of the dark Universe.

Reddick, Rachel M.; Wechsler, Risa H.; Tinker, Jeremy L.; Behroozi, Peter S.

2012-07-11T23:59:59.000Z

67

Automotive fuels. January 1984-February 1992 (Citations from the NTIS Data Base). Rept. for Jan 84-Feb 92  

SciTech Connect (OSTI)

The bibliography contains citations concerning various fuels for the operation of automobiles. Fuels include alcohol, diesel, gasoline, hydrogen, natural gas, methanol, and methane. Topics include exhaust emissions and gases, economy, consumption, antiknock additives, and volatility. (Contains 153 citations with title list and subject index.)

Not Available

1992-01-01T23:59:59.000Z

68

DOI: 10.1007/s00340-008-2998-2 Appl. Phys. B 91, 343348 (2008)  

E-Print Network [OSTI]

- ric lithium niobate (SLN). Although there are several works on the refractive in- dex properties of Mg-phase-matched nonlinear interactions with these two crystal compositions in the near and mid- infrared. The results show.70.Mp 1 Introduction Periodically poled lithium niobate (PPLN) has been used in a wide variety

Arie, Ady

2008-01-01T23:59:59.000Z

69

A&A manuscript no. (will be inserted by hand later)  

E-Print Network [OSTI]

, Ontario, N6A 3K7 Canada 3 Center of Excellence in Information Systems, Tennessee State University abundances of ?? And are found to agree with those of Arcturus within 0.1 dex. In particular, oxygen and light requests to: J.­F. Donati (French address) is thus very similar to Arcturus though somewhat less evolved

Donati, Jean-François

70

Journal of Cellular Biochemistry 90:109120 (2003) Fluorescence Activated Cell Sorting Reveals  

E-Print Network [OSTI]

of CFU-F (fibroblast) colonies that formed in vehicle versus dex. Finally, both cell autonomous and cell Heterogeneous and Cell Non-Autonomous Osteoprogenitor Differentiation in Fetal Rat Calvaria Cell Populations non-autonomous (i.e., inhibitory/stimulatory effects of cell neighbors) differentiation of osteo

Zandstra, Peter W.

71

Supervised Probabilistic Principal Component Analysis Shipeng Yu1,2  

E-Print Network [OSTI]

Siemens AG, Corporate Technology, Information and Communications, Munich, Germany 3 MPI for Biological Cybernetics, T¨ubingen, Germany spyu@dbs.ifi.lmu.de, kai.yu@siemens.com, volker.tresp@siemens.com, kriegel transformation or document in- dexing, is of great importance and has been extensively stud- Permission to make

Tresp, Volker

72

Supervised Probabilistic Principal Component Analysis Shipeng Yu1,2  

E-Print Network [OSTI]

Siemens AG, Corporate Technology, Information and Communications, Munich, Germany 3 MPI for Biological Cybernetics, T¨ubingen, Germany spyu@dbs.ifi.lmu.de, kai.yu@siemens.com, volker.tresp@siemens.com, kriegel-59593-339-5/06/0008 ...$5.00. which is also called feature transformation or document in- dexing, is of great importance

Kriegel, Hans-Peter

73

AHAM: A Dexterbased Reference Model for Adaptive Paul De Bra \\Lambda , GeertJan Houben y and Hongjing Wu  

E-Print Network [OSTI]

AHAM: A Dexterbased Reference Model for Adaptive Hypermedia Paul De Bra \\Lambda , GeertJan Houben, called AHAM, which encompasses most features supported by adaptive systems that exist today in order to be able to explain AHAM rather than formally specify it. AHAM augments Dex ter with features

De Bra, Paul

74

Adaptation and Search: from Dexter and AHAM to GAF Evgeny Knutov  

E-Print Network [OSTI]

Adaptation and Search: from Dexter and AHAM to GAF Evgeny Knutov Dep. of Computer Science Eindhoven, Human Factors 1. INTRODUCTION Since the most cited Adaptive Hypermedia (AH) model AHAM [1] (in 1999) new the evolution of Hypertext/Hypermedia modelling from Dex- ter Model through AHAM to the proposed GAF (Generic

De Bra, Paul

75

Annales Geophysicae, 23, 20512068, 2005 SRef-ID: 1432-0576/ag/2005-23-2051  

E-Print Network [OSTI]

dependence between solar wind parameters and ionospheric total energy consumption computed from a global several activity in- dex proxies, large statistical surveys, assimilative data meth- ods (AMIE, and satellite-based statistics: towards a synthesis M. Palmroth1, P. Janhunen1, T. I. Pulkkinen1, A. Aksnes2, G

?stgaard, Nikolai

76

The Resolved Stellar Populations of a Dwarf Spheroidal Galaxy in the Virgo Cluster  

E-Print Network [OSTI]

We report on the discovery of a faint (M_V ~ -10.6 +/- 0.2) dwarf spheroidal galaxy on deep F606W and F814W Hubble Space Telescope images of a Virgo intracluster field. The galaxy is easily resolved in our images, as our color magnitude diagram (CMD) extends > 1 magnitude beyond the tip of the red giant branch (RGB). Thus, it is the deepest CMD for a small dwarf galaxy inside a cluster environment. Using the colors of the RGB stars, we derive a metal abundance for the dwarf of [M/H]= -2.3 +/- 0.3, and show that the metallicity dispersion is less than 0.6 dex at 95% confidence. We also use the galaxy's lack of AGB stars and the absence of objects brighter than M_bol ~ -4.1 +/- 0.2 to show that the system is old (t >~10 Gyr). Finally, we derive the object's structural parameters, and show that the galaxy displays no obvious evidence of tidal threshing. Since the tip of the red giant branch distance ((m-M)_0 = 31.23 +/- 0.17 or D = 17.6 +/- 1.4 Mpc) puts the galaxy near the core of the Virgo cluster, one might expect the object to have undergone some tidal processing. Yet the chemical and morphological similarity between the dwarf and the dSph galaxies of the Local and M81 Group demonstrates that the object is indeed pristine, and not the shredded remains of a much larger galaxy. We discuss the possible origins of this galaxy, and suggest that it is just now falling into Virgo for the first time.

Patrick R. Durrell; Benjamin F. Williams; Robin Ciardullo; John J. Feldmeier; Ted von Hippel; Steinn Sigurdsson; George H. Jacoby; Henry C. Ferguson; Nial R. Tanvir; Magda Arnaboldi; Ortwin Gerhard; J. Alfonso L. Aguerri; Ken Freeman; Matt Vinciguerra

2006-11-06T23:59:59.000Z

77

EVIDENCE THAT GAMMA-RAY BURST 130702A EXPLODED IN A DWARF SATELLITE OF A MASSIVE GALAXY  

SciTech Connect (OSTI)

GRB 130702A is a nearby long-duration gamma-ray burst (LGRB) discovered by the Fermi satellite whose associated afterglow was detected by the Palomar Transient Factory. Subsequent photometric and spectroscopic monitoring has identified a coincident broad-lined Type Ic supernova (SN), and nebular emission detected near the explosion site is consistent with a redshift of z = 0.145. The SN-GRB exploded at an offset of {approx}7.''6 from the center of an inclined r = 18.1 mag red disk-dominated galaxy, and {approx}0.''6 from the center of a much fainter r = 23 mag object. We obtained Keck-II DEIMOS spectra of the two objects and find a 2{sigma} upper limit on their line-of-sight velocity offset of {approx}<60 km s{sup -1}. If we calculate the inclination angle of the massive red galaxy from its axis ratio and assume that its light is dominated by a very thin disk, the explosion would have a {approx}60 kpc central offset, or {approx}9 times the galaxy's half-light radius. A significant bulge or a thicker disk would imply a higher inclination angle and greater central offset. The substantial offset suggests that the faint source is a separate dwarf galaxy. The star-formation rate of the dwarf galaxy is {approx}0.05 M{sub Sun} yr{sup -1}, and we place an upper limit on its oxygen abundance of 12 + log(O/H) < 8.16 dex. The identification of an LGRB in a dwarf satellite of a massive, metal-rich primary galaxy suggests that recent detections of LGRBs spatially coincident with metal-rich galaxies may be, in some cases, superpositions.

Kelly, Patrick L.; Filippenko, Alexei V.; Fox, Ori D.; Zheng Weikang; Clubb, Kelsey I., E-mail: pkelly@astro.berkeley.edu [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)

2013-09-20T23:59:59.000Z

78

TYPE Ia SUPERNOVA REMNANT SHELL AT z = 3.5 SEEN IN THE THREE SIGHTLINES TOWARD THE GRAVITATIONALLY LENSED QSO B1422+231  

SciTech Connect (OSTI)

Using the Subaru 8.2 m Telescope with the IRCS Echelle spectrograph, we obtained high-resolution (R = 10,000) near-infrared (1.01-1.38 {mu}m) spectra of images A and B of the gravitationally lensed QSO B1422+231 (z = 3.628) consisting of four known lensed images. We detected Mg II absorption lines at z = 3.54, which show a large variance of column densities ({approx}0.3 dex) and velocities ({approx}10 km s{sup -1}) between sightlines A and B with a projected separation of only 8.4h{sup -1}{sub 70} pc at that redshift. This is the smallest spatial structure of the high-z gas clouds ever detected after Rauch et al. found a 20 pc scale structure for the same z = 3.54 absorption system using optical spectra of images A and C. The observed systematic variances imply that the system is an expanding shell as originally suggested by Rauch et al. By combining the data for three sightlines, we managed to constrain the radius and expansion velocity of the shell ({approx}50-100 pc, 130 km s{sup -1}), concluding that the shell is truly a supernova remnant (SNR) rather than other types of shell objects, such as a giant H II region. We also detected strong Fe II absorption lines for this system, but with much broader Doppler width than that of {alpha}-element lines. We suggest that this Fe II absorption line originates in a localized Fe II-rich gas cloud that is not completely mixed with plowed ambient interstellar gas clouds showing other {alpha}-element low-ion absorption lines. Along with the Fe richness, we conclude that the SNR is produced by an SN Ia explosion.

Hamano, Satoshi; Kobayashi, Naoto [Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Kondo, Sohei [Koyama Astronomical Observatory, Kyoto-Sangyo University, Motoyama, Kamigamo, Kita-Ku, Kyoto 603-8555 (Japan); Tsujimoto, Takuji [National Astronomical Observatory of Japan and Department of Astronomical Science, Graduate University for Advanced Studies, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Okoshi, Katsuya [Faculty of Industrial Science and Technology, Tokyo University of Science, 102-1 Tomino, Oshamanbe, Hokkaido 049-3514 (Japan); Shigeyama, Toshikazu, E-mail: hamano@ioa.s.u-tokyo.ac.jp [Research Center for the Early Universe, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan)

2012-08-01T23:59:59.000Z

79

Parallel In Situ Indexing for Data-intensive Computing  

SciTech Connect (OSTI)

As computing power increases exponentially, vast amount of data is created by many scientific re- search activities. However, the bandwidth for storing the data to disks and reading the data from disks has been improving at a much slower pace. These two trends produce an ever-widening data access gap. Our work brings together two distinct technologies to address this data access issue: indexing and in situ processing. From decades of database research literature, we know that indexing is an effective way to address the data access issue, particularly for accessing relatively small fraction of data records. As data sets increase in sizes, more and more analysts need to use selective data access, which makes indexing an even more important for improving data access. The challenge is that most implementations of in- dexing technology are embedded in large database management systems (DBMS), but most scientific datasets are not managed by any DBMS. In this work, we choose to include indexes with the scientific data instead of requiring the data to be loaded into a DBMS. We use compressed bitmap indexes from the FastBit software which are known to be highly effective for query-intensive workloads common to scientific data analysis. To use the indexes, we need to build them first. The index building procedure needs to access the whole data set and may also require a significant amount of compute time. In this work, we adapt the in situ processing technology to generate the indexes, thus removing the need of read- ing data from disks and to build indexes in parallel. The in situ data processing system used is ADIOS, a middleware for high-performance I/O. Our experimental results show that the indexes can improve the data access time up to 200 times depending on the fraction of data selected, and using in situ data processing system can effectively reduce the time needed to create the indexes, up to 10 times with our in situ technique when using identical parallel settings.

Kim, Jinoh; Abbasi, Hasan; Chacon, Luis; Docan, Ciprian; Klasky, Scott; Liu, Qing; Podhorszki, Norbert; Shoshani, Arie; Wu, Kesheng

2011-09-09T23:59:59.000Z

80

Novel Characterization of GDI Engine Exhaust for Gasoline and Mid-Level Gasoline-Alcohol Blends  

SciTech Connect (OSTI)

Gasoline direct injection (GDI) engines can offer improved fuel economy and higher performance over their port fuel-injected (PFI) counterparts, and are now appearing in increasingly more U.S. and European vehicles. Small displacement, turbocharged GDI engines are replacing large displacement engines, particularly in light-duty trucks and sport utility vehicles, in order for manufacturers to meet more stringent fuel economy standards. GDI engines typically emit the most particulate matter (PM) during periods of rich operation such as start-up and acceleration, and emissions of air toxics are also more likely during this condition. A 2.0 L GDI engine was operated at lambda of 0.91 at typical loads for acceleration (2600 rpm, 8 bar BMEP) on three different fuels; an 87 anti-knock index (AKI) gasoline (E0), 30% ethanol blended with the 87 AKI fuel (E30), and 48% isobutanol blended with the 87 AKI fuel. E30 was chosen to maximize octane enhancement while minimizing ethanol-blend level and iBu48 was chosen to match the same fuel oxygen level as E30. Particle size and number, organic carbon and elemental carbon (OC/EC), soot HC speciation, and aldehydes and ketones were all analyzed during the experiment. A new method for soot HC speciation is introduced using a direct, thermal desorption/pyrolysis inlet for the gas chromatograph (GC). Results showed high levels of aromatic compounds were present in the PM, including downstream of the catalyst, and the aldehydes were dominated by the alcohol blending.

Storey, John Morse [ORNL] [ORNL; Lewis Sr, Samuel Arthur [ORNL] [ORNL; Szybist, James P [ORNL] [ORNL; Thomas, John F [ORNL] [ORNL; Barone, Teresa L [ORNL] [ORNL; Eibl, Mary A [ORNL] [ORNL; Nafziger, Eric J [ORNL] [ORNL; Kaul, Brian C [ORNL] [ORNL

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "antiknock in dex" 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

1, vol.97, no.5, pp.353358, 2014. Big Data Analysis by Density Ratio Estimation  

E-Print Network [OSTI]

}nde j=1 r (x) = p nu(x) p de(x) `nu' `de' (numerator) (denominator) {xnu i }nnu i=1 p nu(x) {xde j }nde j=1 p de(x) r (x) = p nu(x)/p de(x) 1 p nu(x) p de(x) r (x) = p nu(x)/p de(x) [1] 2.1 p nu(x) p de') p(y = `nu') p (y = `nu'|x) p(y = `de'|x) p (y) p (y|x) {xnu i }nnu i=1 {xde j }nde j=1 p(y|x) r(x) r

Sugiyama, Masashi

82

Accurate Gravities of F, G, and K stars from High Resolution Spectra Without External Constraints  

E-Print Network [OSTI]

We demonstrate a new procedure to derive accurate and precise surface gravities from high resolution spectra without the use of external constraints. Our analysis utilizes Spectroscopy Made Easy (SME) with robust spectral line constraints and uses an iterative process to mitigate degeneracies in the fitting process. We adopt an updated radiative transfer code, a new treatment for neutral perturber broadening, a line list with multiple gravity constraints and separate fitting for global stellar properties and abundance determinations. To investigate the sources of temperature dependent trends in determining log g noted in previous studies, we obtained Keck HIRES spectra of 42 Kepler asteroseismic stars. In comparison to asteroseismically determined log g our spectroscopic analysis has a constant offset of 0.01 dex with a root mean square (RMS) scatter of 0.05 dex. We also analyzed 30 spectra which had published surface gravities determined using the $a/R_*$ technique from planetary transits and found a constan...

Brewer, John M; Basu, Sarbani; Valenti, Jeff A; Piskunov, Nikolai

2015-01-01T23:59:59.000Z

83

ISO-SWS calibration and the accurate modelling of cool-star atmospheres: I. Method  

E-Print Network [OSTI]

A detailed spectroscopic study of the ISO-SWS data of the red giant Alpha Tau is presented, which enables not only the accurate determination of the stellar parameters of Alpha Tau, but also serves as a critical review of the ISO-SWS calibration. This study is situated in a broader context of an iterative process in which both accurate observations of stellar templates and cool star atmosphere models are involved to improve the ISO-SWS calibration process as well as the theoretical modelling of stellar atmospheres. Therefore a sample of cool stars, covering the whole A0 -- M8 spectral classification, has been observed in order to disentangle calibration problems and problems in generating the theoretical models and corresponding synthetic spectrum. By using stellar parameters found in the literature large discrepancies were seen between the ISO-SWS data and the generated synthetic spectrum of Alpha Tau. A study of the influence of various stellar parameters on the theoretical models and synthetic spectra, in conjunction with the Kolmogorov-Smirnov test to evaluate objectively the goodness-of-fit, enables us to pin down the stellar parameters with a high accuracy: Teff = 3850 +/- 70 K, log g = 1.50 +/- 0.15, M = 2.3 +/- 0.8 Msun, z = -0.15 +/- 0.20 dex, microturbulence = 1.7 +/- 0.3 km/s, 12C/13C= 10 +/- 1, abundance of C = 8.35 +/- 0.20 dex, abundance of N= 8.35 +/- 0.25 dex, abundance of O = 8.83 +/- 0.15 dex and the angular diameter is 20.77 +/- 0.83 mas. These atmospheric parameters were then compared with the results provided by other authors using other methods and/or spectra.

L. Decin; C. Waelkens; K. Eriksson; B. Gustafsson; B. Plez; A. J. Sauval; W. Van Assche; B. Vandenbussche

2000-08-21T23:59:59.000Z

84

A&A manuscript no. (will be inserted by hand later)  

E-Print Network [OSTI]

are approximately solar above [Fe/H] ;2:2 where they decrease rapidly by 0.5 - 0.6 dex. The direct method based offprint requests to: L. Mashonkina, e-mail: ml@astro.ksu.ras.ru ? Based on observations at the German- citation energy of 0:7 eV) these Ba II lines can be detected even in extremely metal-poor stars. Two types

Gehren, Thomas

85

TRACING THE ORPHAN STREAM TO 55 kpc WITH RR LYRAE STARS  

SciTech Connect (OSTI)

We report positions, velocities, and metallicities of 50 ab-type RR Lyrae (RRab) stars observed in the vicinity of the Orphan stellar stream. Using about 30 RRab stars classified as being likely members of the Orphan stream, we study the metallicity and the spatial extent of the stream. We find that RRab stars in the Orphan stream have a wide range of metallicities, from 1.5 dex to 2.7 dex. The average metallicity of the stream is 2.1 dex, identical to the value obtained by Newberg et al. using blue horizontal branch stars. We find that the most distant parts of the stream (40-50 kpc from the Sun) are about 0.3 dex more metal-poor than the closer parts (within ?30 kpc), suggesting a possible metallicity gradient along the stream's length. We have extended the previous studies and have mapped the stream up to 55 kpc from the Sun. Even after a careful search, we did not identify any more distant RRab stars that could plausibly be members of the Orphan stream. If confirmed with other tracers, this result would indicate a detection of the end of the leading arm of the stream. We have compared the distances of Orphan stream RRab stars with the best-fit orbits obtained by Newberg et al. We find that model 6 of Newberg et al. cannot explain the distances of the most remote Orphan stream RRab stars, and conclude that the best fit to distances of Orphan stream RRab stars and to the local circular velocity is provided by potentials where the total mass of the Galaxy within 60 kpc is M{sub 60} ? 2.7 10{sup 11} M{sub ?}, or about 60% of the mass found by previous studies. More extensive modeling that would consider non-spherical potentials and the possibility of misalignment between the stream and the orbit is highly encouraged.

Sesar, Branimir; Cohen, Judith G.; Bellm, Eric C.; Levitan, David; Tang, Sumin; Waszczak, Adam; Kulkarni, Shrinivas R.; Prince, Thomas A. [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Grillmair, Carl J.; Laher, Russ R.; Surace, Jason A. [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Bhalerao, Varun B. [Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411 007 (India); Ofek, Eran O., E-mail: bsesar@astro.caltech.edu [Benoziyo Center for Astrophysics, Weizmann Institute of Science, 76100 Rehovot (Israel)

2013-10-10T23:59:59.000Z

86

The Relation between Dynamical Mass-to-Light Ratio and Color for Massive Quiescent Galaxies out to z~2 and Comparison with Stellar Population Synthesis Models  

E-Print Network [OSTI]

We explore the relation between the dynamical mass-to-light ratio ($M/L$) and rest-frame color of massive quiescent galaxies out to z~2. We use a galaxy sample with measured stellar velocity dispersions in combination with Hubble Space Telescope and ground-based multi-band photometry. Our sample spans a large range in $\\log M_{dyn}/L_{g}$ (of 1.6~dex) and $\\log M_{dyn}/L_{K}$ (of 1.3~dex). There is a strong, approximately linear correlation between the $M/L$ for different wavebands and rest-frame color. The root-mean-scatter scatter in $\\log~M_{dyn}/L$ residuals implies that it is possible to estimate the $M/L$ with an accuracy of ~0.25 dex from a single rest-frame optical color. Stellar population synthesis (SPS) models with a Salpeter stellar initial mass function (IMF) can not simultaneously match $M_{dyn}/L_{g}$ vs. $(g-z)_{rest-frame}$ and $M_{dyn}/L_{K}$ vs. $(g-K)_{rest-frame}$. By changing the slope of the IMF we are still unable to explain the M/L of the bluest and reddest galaxies. We find that an I...

van de Sande, Jesse; Franx, Marijn; Bezanson, Rachel; van Dokkum, Pieter G

2014-01-01T23:59:59.000Z

87

Study Agriculture Abroad Check with the Study Abroad office for up to date costs, course restrictions, and application processes.  

E-Print Network [OSTI]

)* Australia - University of Western Australia (DEX) La Trobe University - Melbourne (ISEP) Finland Australia (DEX) La Trobe University - Melbourne (ISEP) Finland - University of Turku (ISEP) Univeristy) Sustainable Food & Bioenergy Systems Argentina - Universidad de Belgrano (CCIS)* Universidad del Salvador

Maxwell, Bruce D.

88

THE CO-TO-H{sub 2} CONVERSION FACTOR AND DUST-TO-GAS RATIO ON KILOPARSEC SCALES IN NEARBY GALAXIES  

SciTech Connect (OSTI)

We present ?kiloparsec spatial resolution maps of the CO-to-H{sub 2} conversion factor (?{sub CO}) and dust-to-gas ratio (DGR) in 26 nearby, star-forming galaxies. We have simultaneously solved for ?{sub CO} and the DGR by assuming that the DGR is approximately constant on kiloparsec scales. With this assumption, we can combine maps of dust mass surface density, CO-integrated intensity, and H I column density to solve for both ?{sub CO} and the DGR with no assumptions about their value or dependence on metallicity or other parameters. Such a study has just become possible with the availability of high-resolution far-IR maps from the Herschel key program KINGFISH, {sup 12}CO J = (2-1) maps from the IRAM 30 m large program HERACLES, and H I 21 cm line maps from THINGS. We use a fixed ratio between the (2-1) and (1-0) lines to present our ?{sub CO} results on the more typically used {sup 12}CO J = (1-0) scale and show using literature measurements that variations in the line ratio do not affect our results. In total, we derive 782 individual solutions for ?{sub CO} and the DGR. On average, ?{sub CO} = 3.1 M{sub ?} pc{sup 2} (K km s{sup 1}){sup 1} for our sample with a standard deviation of 0.3 dex. Within galaxies, we observe a generally flat profile of ?{sub CO} as a function of galactocentric radius. However, most galaxies exhibit a lower ?{sub CO} value in the central kiloparseca factor of ?2 below the galaxy mean, on average. In some cases, the central ?{sub CO} value can be factors of 5-10 below the standard Milky Way (MW) value of ?{sub CO,{sub MW}} = 4.4 M{sub ?} pc{sup 2} (K km s{sup 1}){sup 1}. While for ?{sub CO} we find only weak correlations with metallicity, the DGR is well-correlated with metallicity, with an approximately linear slope. Finally, we present several recommendations for choosing an appropriate ?{sub CO} for studies of nearby galaxies.

Sandstrom, K. M.; Walter, F. [Max Planck Institut fr Astronomie, Knigstuhl 17, D-69117 Heidelberg (Germany); Leroy, A. K. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Bolatto, A. D.; Wolfire, M. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Croxall, K. V.; Crocker, A. [Department of Physics and Astronomy, Mail Drop 111, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 (United States); Draine, B. T.; Aniano, G. [Princeton University Observatory, Peyton Hall, Princeton, NJ 08544-1001 (United States); Wilson, C. D. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Calzetti, D. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Kennicutt, R. C.; Galametz, M. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Donovan Meyer, J. [Department of Physics and Astronomy, SUNY Stony Brook, Stony Brook, NY 11794-3800 (United States); Usero, A. [Observatorio Astronmico Nacional, Alfonso XII, 3, E-28014 Madrid (Spain); Bigiel, F. [Institut fr theoretische Astrophysik, Zentrum fr Astronomie der Universitt Heidelberg, Albert-Ueberle Str. 2, D-69120 Heidelberg (Germany); Brinks, E. [Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); De Blok, W. J. G. [ASTRON, The Netherlands Institute for Radio Astronomy, Postbus 2, 7990-AA Dwingeloo (Netherlands); Dale, D. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Engelbracht, C. W., E-mail: sandstrom@mpia.de [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); and others

2013-11-01T23:59:59.000Z

89

The Absence of an Environmental Dependence in the Mass-Metallicity Relation at z=2  

E-Print Network [OSTI]

We investigate the environmental dependence of the mass-metallicity relation at z=2 with MOSFIRE/Keck as part of the ZFIRE survey. Here, we present the chemical abundance of a Virgo-like progenitor at z=2.095 that has an established red sequence. We identified 43 cluster ($=2.095\\pm0.004$) and 74 field galaxies ($=2.195\\pm0.083$) for which we can measure metallicities. For the first time, we show that there is no discernible difference between the mass-metallicity relation of field and cluster galaxies to within 0.02dex. Both our field and cluster galaxy mass-metallicity relations are consistent with recent field galaxy studies at z~2. We present hydrodynamical simulations for which we derive mass-metallicity relations for field and cluster galaxies. We find at most a 0.1dex offset towards more metal-rich simulated cluster galaxies. Our results from both simulations and observations are suggestive that environmental effects, if present, are small and are secondary to the ongoing inflow and outflow processes t...

Kacprzak, Glenn G; Nanayakkara, Themiya; Kobayashi, Chiaki; Tran, Kim-Vy H; Kewley, Lisa J; Glazebrook, Karl; Spitler, Lee; Taylor, Philip; Cowley, Michael; Labb, Ivo; Straatman, Caroline; Tomczak, Adam

2015-01-01T23:59:59.000Z

90

Dark Matter and Stellar Mass in the Luminous Regions of Disk Galaxies  

E-Print Network [OSTI]

We investigate the correlations among stellar mass (M_*), disk scale length (R_d), and rotation velocity at 2.2 disk scale lengths (V_2.2) for a sample of 81 disk-dominated galaxies (disk/total >= 0.9) selected from the SDSS. We measure V_2.2 from long-slit H-alpha rotation curves and infer M_* from galaxy i-band luminosities (L_i) and g-r colors. We find logarithmic slopes of 2.60+/-0.13 and 3.05+/-0.12 for the L_i-V_2.2 and M_*-V_2.2 relations, somewhat shallower than most previous studies, with intrinsic scatter of 0.13 dex and 0.16 dex. Our direct estimates of the total-to-stellar mass ratio within 2.2R_d, assuming a Kroupa IMF, yield a median ratio of 2.4 for M_*>10^10 Msun and 4.4 for M_*=10^9-10^10 Msun, with large scatter at a given M_* and R_d. The typical ratio of the rotation speed predicted for the stellar disk alone to the observed rotation speed at 2.2R_d is ~0.65. The distribution of R_d at fixed M_* is broad, but we find no correlation between disk size and the residual from the M_*-V_2.2 rela...

Pizagno, J; Weinberg, D H; Rix, H W; Harbeck, D; Grebel, E K; Bell, E; Brinkmann, J; Holtzman, J; West, A; Pizagno, James; Prada, Francisco; Weinberg, David H.; Rix, Hans-Walter; Harbek, Daniel; Grebel, Eva K.; Bell, Eric; Brinkmann, Jon; Holtzman, Jon; West, Andrew

2005-01-01T23:59:59.000Z

91

MOLECULAR GAS AND STAR FORMATION IN NEARBY DISK GALAXIES  

SciTech Connect (OSTI)

We compare molecular gas traced by {sup 12}CO (2-1) maps from the HERACLES survey, with tracers of the recent star formation rate (SFR) across 30 nearby disk galaxies. We demonstrate a first-order linear correspondence between {Sigma}{sub mol} and {Sigma}{sub SFR} but also find important second-order systematic variations in the apparent molecular gas depletion time, {tau}{sub dep}{sup mol}={Sigma}{sub mol}/{Sigma}{sub SFR}. At the 1 kpc common resolution of HERACLES, CO emission correlates closely with many tracers of the recent SFR. Weighting each line of sight equally, using a fixed {alpha}{sub CO} equivalent to the Milky Way value, our data yield a molecular gas depletion time, {tau}{sub dep}{sup mol}={Sigma}{sub mol}/{Sigma}{sub SFR}{approx}2.2 Gyr with 0.3 dex 1{sigma} scatter, in very good agreement with recent literature data. We apply a forward-modeling approach to constrain the power-law index, N, that relates the SFR surface density and the molecular gas surface density, {Sigma}{sub SFR}{proportional_to}{Sigma}{sub mol}{sup N}. We find N = 1 {+-} 0.15 for our full data set with some scatter from galaxy to galaxy. This also agrees with recent work, but we caution that a power-law treatment oversimplifies the topic given that we observe correlations between {tau}{sub dep}{sup mol} and other local and global quantities. The strongest of these are a decreased {tau}{sub dep}{sup mol} in low-mass, low-metallicity galaxies and a correlation of the kpc-scale {tau}{sub dep}{sup mol} with dust-to-gas ratio, D/G. These correlations can be explained by a CO-to-H{sub 2} conversion factor ({alpha}{sub CO}) that depends on dust shielding, and thus D/G, in the theoretically expected way. This is not a unique interpretation, but external evidence of conversion factor variations makes this the most conservative explanation of the strongest observed {tau}{sub dep}{sup mol} trends. After applying a D/G-dependent {alpha}{sub CO}, some weak correlations between {tau}{sub dep}{sup mol} and local conditions persist. In particular, we observe lower {tau}{sub dep}{sup mol} and enhanced CO excitation associated with nuclear gas concentrations in a subset of our targets. These appear to reflect real enhancements in the rate of star formation per unit gas, and although the distribution of {tau}{sub dep} does not appear bimodal in galaxy centers, {tau}{sub dep} does appear multivalued at fixed {Sigma}{sub H2}, supporting the idea of ''disk'' and ''starburst'' modes driven by other environmental parameters.

Leroy, Adam K.; Munoz-Mateos, Juan-Carlos [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Walter, Fabian; Sandstrom, Karin; Meidt, Sharon; Rix, Hans-Walter; Schinnerer, Eva [Max Planck Institute fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Schruba, Andreas [California Institute for Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Bigiel, Frank [Theoretische Astrophysik, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany); Bolatto, Alberto [Department of Astronomy, University of Maryland, College Park, MD (United States); Brinks, Elias [Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); De Blok, W. J. G. [Astrophysics, Cosmology and Gravity Centre, Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch 7701 (South Africa); Rosolowsky, Erik [University of British Columbia, Okanagan Campus, Kelowna, BC (Canada); Schuster, Karl-Friedrich [IRAM, 300 rue de la Piscine, F-38406 St. Martin d'Heres (France); Usero, Antonio [Observatorio Astronomico Nacional, C/ Alfonso XII, 3, E-28014 Madrid (Spain)

2013-08-01T23:59:59.000Z

92

Kinetic Modeling of Toluene Oxidation for Surrogate Fuel Applications  

SciTech Connect (OSTI)

New environmental issues, like the effect of combustion-generated greenhouse gases, provide motivation to better characterize oxidation of hydrocarbons. Transportation, in particular, significantly contributes to energy consumption and CO{sub 2} emissions. Kinetic studies about the combustion of fuels under conditions typical of internal combustion engines provides important support to improve mechanism formulation and to eventually provide better computational tools that can be used to increase the engine performance. It is foreseeable that at least in the next 30 years the main transportation fuels will be either gasoline or diesel. Unfortunately, these fuels are very complex mixtures of many components. Moreover, their specifications and performance requirements significantly change the composition of these fuels: gasoline and diesel mixtures are different if coming from different refineries or they are different from winter to summer. At the same time a fuel with a well defined and reproducible composition is needed for both experimental and modeling work. In response to these issues, surrogate fuels are proposed. Surrogate fuels are defined as mixtures of a small number of hydrocarbons whose relative concentrations is adjusted in order to approximate the chemical and physical properties of a real fuel. Surrogate fuels are then very useful both for the design of reproducible experimental tests and also for the development of reliable kinetic models. The primary reference fuels (PRF) are a typical and old example of surrogate fuel: n-heptane and iso-octane mixtures are used to reproduce antiknock propensity of complex mixtures contained in a gasoline. PRFs are not able to surrogate gasoline in operating conditions different from standard ones and new surrogates have been recently proposed. Toluene is included in all of them as a species able to represent the behavior of aromatic compounds. On the other side, the toluene oxidation chemistry is not so well established and uncertainties still remain in the mechanism. This is especially true in the low temperature regime (< 850K). In these conditions, the toluene reactivity is too low to be conveniently investigated. Nonetheless, gasoline surrogates work in the engine at low temperatures, because of the presence of very reactive alkanes. The effect of these component interactions have to be taken into account. This work's aim is to present the model activity carried out by two different research groups, comparing the main pathways and results, matching data carried out in different devices both for pure toluene and mixtures. This is the starting point for a further activity to improve the two kinetic schemes.

Frassoldati, A; Mehl, M; Fietzek, R; Faravelli, T; Pitz, W J; Ranzi, E

2009-04-21T23:59:59.000Z

93

THE DEPENDENCE OF BROWN DWARF RADII ON ATMOSPHERIC METALLICITY AND CLOUDS: THEORY AND COMPARISON WITH OBSERVATIONS  

SciTech Connect (OSTI)

Employing realistic and consistent atmosphere boundary conditions, we have generated evolutionary models for brown dwarfs and very low mass stars (VLMs) for different atmospheric metallicities ([Fe/H]), with and without clouds. We find that the spread in radius at a given mass and age can be as large as {approx}10% to {approx}25%, with higher-metallicity, higher-cloud-thickness atmospheres resulting quite naturally in larger radii. For each 0.1 dex increase in [Fe/H], radii increase by {approx}1% to {approx}2.5%, depending upon the age and mass. We also find that, while for smaller masses and older ages brown dwarf radii decrease with increasing helium fraction (Y, as expected), for more massive brown dwarfs and a wide range of ages they increase with helium fraction. The increase in radius in going from Y = 0.25 to Y = 0.28 can be as large as {approx}0.025 R{sub J} ({approx}2.5%). Furthermore, we find that for VLMs an increase in atmospheric metallicity from 0.0 to 0.5 dex, increases radii by {approx}4%, and from -0.5 to 0.5 dex by {approx}10%. Therefore, we suggest that opacity due to higher metallicity might naturally account for the apparent radius anomalies in some eclipsing VLM systems. Ten to twenty-five percent variations in radius exceed errors stemming from uncertainties in the equation of state alone. This serves to emphasize that transit and eclipse measurements of brown dwarf radii constrain numerous effects collectively, importantly including the atmosphere and condensate cloud models, and not just the equation of state. At all times, one is testing a multi-parameter theory, and not a universal radius-mass relation.

Burrows, Adam; Nampaisarn, Thane [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Heng, Kevin, E-mail: burrows@astro.princeton.edu, E-mail: tnampais@astro.princeton.edu, E-mail: kheng@phys.ethz.ch [Institute for Advanced Study, School of Natural Sciences, 1 Einstein Drive, Princeton, NJ 08540 (United States)

2011-07-20T23:59:59.000Z

94

Three-Dimensional Spectral Classification of Low-Metallicity Stars Using Artificial Neural Networks  

E-Print Network [OSTI]

We explore the application of artificial neural networks (ANNs) for the estimation of atmospheric parameters (Teff, logg, and [Fe/H]) for Galactic F- and G-type stars. The ANNs are fed with medium-resolution (~ 1-2 A) non flux-calibrated spectroscopic observations. From a sample of 279 stars with previous high-resolution determinations of metallicity, and a set of (external) estimates of temperature and surface gravity, our ANNs are able to predict Teff with an accuracy of ~ 135-150 K over the range 4250 <= Teff <= 6500 K, logg with an accuracy of ~ 0.25-0.30 dex over the range 1.0 <= logg <= 5.0 dex, and [Fe/H] with an accuracy ~ 0.15-0.20 dex over the range -4.0 <= [Fe/H] <= +0.3. Such accuracies are competitive with the results obtained by fine analysis of high-resolution spectra. It is noteworthy that the ANNs are able to obtain these results without consideration of photometric information for these stars. We have also explored the impact of the signal-to-noise ratio (S/N) on the behavior of ANNs, and conclude that, when analyzed with ANNs trained on spectra of commensurate S/N, it is possible to extract physical parameter estimates of similar accuracy with stellar spectra having S/N as low as 13. Taken together, these results indicate that the ANN approach should be of primary importance for use in present and future large-scale spectroscopic surveys.

Shawn Snider; Carlos Allende Prieto; Ted von Hippel; Timothy C. Beers; Christopher Sneden; Yuan Qu; and Silvia Rossi

2001-07-20T23:59:59.000Z

95

CARBON-ENHANCED METAL-POOR STARS IN SDSS/SEGUE. I. CARBON ABUNDANCE ESTIMATION AND FREQUENCY OF CEMP STARS  

SciTech Connect (OSTI)

We describe a method for the determination of stellar [C/Fe] abundance ratios using low-resolution (R = 2000) stellar spectra from the Sloan Digital Sky Survey (SDSS) and its Galactic sub-survey, the Sloan Extension for Galactic Understanding and Exploration (SEGUE). By means of a star-by-star comparison with a set of SDSS/SEGUE spectra with available estimates of [C/Fe] based on published high-resolution analyses, we demonstrate that we can measure [C/Fe] from SDSS/SEGUE spectra with S/N ? 15 {sup 1} to a precision better than 0.35 dex for stars with atmospheric parameters in the range T {sub eff} = [4400, 6700] K, log g = [1.0, 5.0], [Fe/H] = [4.0, +0.5], and [C/Fe] = [0.25, +3.5]. Using the measured carbon-to-iron abundance ratios obtained by this technique, we derive the frequency of carbon-enhanced stars ([C/Fe] ? +0.7) as a function of [Fe/H], for both the SDSS/SEGUE stars and other samples from the literature. We find that the differential frequency slowly rises from almost zero to about 14% at [Fe/H] ? 2.4, followed by a sudden increase, by about a factor of three, to 39% from [Fe/H] ? 2.4 to [Fe/H] ? 3.7. Although the number of stars known with [Fe/H] < 4.0 remains small, the frequency of carbon-enhanced metal-poor (CEMP) stars below this value is around 75%. We also examine how the cumulative frequency of CEMP stars varies across different luminosity classes. The giant sample exhibits a cumulative CEMP frequency of 32% for [Fe/H] ? 2.5, 31% for [Fe/H] ? 3.0, and 33% for [Fe/H] ? 3.5; a roughly constant value. For the main-sequence turnoff stars, we obtain a lower cumulative CEMP frequency, around 10% for [Fe/H] ? 2.5, presumably due to the difficulty of identifying CEMP stars among warmer turnoff stars with weak CH G-bands. The dwarf population displays a large change in the cumulative frequency for CEMP stars below [Fe/H] = 2.5, jumping from 15% for [Fe/H] ? 2.5 to about 75% for [Fe/H] ? 3.0. When we impose a restriction with respect to distance from the Galactic mid-plane (|Z| < 5 kpc), the frequency of the CEMP giants does not increase at low metallicity ([Fe/H] < 2.5), but rather decreases due to the dilution of C-rich material in stars that have undergone mixing with CNO-processed material from their interiors. The frequency of CEMP stars near the main-sequence turnoff, which are not expected to have experienced mixing, increases for [Fe/H] ? 3.0. The general rise in the global CEMP frequency at low metallicity is likely due to the transition from the inner-halo to the outer-halo stellar populations with declining metallicity and increasing distance from the plane.

Lee, Young Sun [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); Beers, Timothy C.; Placco, Vinicius M. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Masseron, Thomas [Institut d'Astronomie et d'Astrophysique, Universit Libre de Bruxelles, CP 226, Boulevard du Triomphe, B-1050 Bruxelles (Belgium); Plez, Bertrand [Laboratoire Univers et Particules de Montpellier, Universit Montpellier 2, CNRS, F-34095 Montpellier (France); Rockosi, Constance M. [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Sobeck, Jennifer [Laboratoire Lagrange (UMR7293), Universit de Nice Sophia Antipolis, CNRS, Observatoire de la Cte d'Azur, BP 4229, F-06304 Nice Cedex 04 (France); Yanny, Brian [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Lucatello, Sara [INAF-Osservatorio Astronomico di Padova, vicolo dell'Osservatorio 5, I-35122 Padova (Italy); Sivarani, Thirupathi [Indian Institute of Astrophysics, 2nd block Koramangala, Bangalore-560034 (India); Carollo, Daniela, E-mail: yslee@nmsu.edu [Department of Physics and Astronomy, Astronomy, Astrophysics and Astrophotonic Research Center, Macquarie University, North Ryde, NSW 2019 (Australia)

2013-11-01T23:59:59.000Z

96

~ 15206 Station 7 Stat io 6 A 15415 } ~ 15455 ". ~ '15405  

E-Print Network [OSTI]

;N t o.51 ,II KILOMETER olM0CRATER _6STATIONr-PHYSIOGRAPHIC BOUNDARY _-6 6A SPUR~7 ()DEX 8-0 -3 MARE

Rathbun, Julie A.

97

1, pp.588-589, 2013 Density Ratio Estimation  

E-Print Network [OSTI]

://sugiyama-www.cs.titech.ac.jp/~sugi [1] 1 p nu(x) {xnu i }nnu i=1 p de(x) {xde j }nde j=1 r (x) = p nu(x)/p de(x) `nu' `de'|x) p(y = `de'|x) p (y) p (y|x) {xnu i }nnu i=1 {xde j }nde j=1 p(y|x) r(x) r(x) = nde nnu p {xnu i }nnu i=1 {xde j }nde j=1 p nu(u) p de(u) Ep de [(p nu(u)/p de(u) - 1)2 ] 2 2

Sugiyama, Masashi

98

VERIFICATION OF THE KEPLER INPUT CATALOG FROM ASTEROSEISMOLOGY OF SOLAR-TYPE STARS  

SciTech Connect (OSTI)

We calculate precise stellar radii and surface gravities from the asteroseismic analysis of over 500 solar-type pulsating stars observed by the Kepler space telescope. These physical stellar properties are compared with those given in the Kepler Input Catalog (KIC), determined from ground-based multi-color photometry. For the stars in our sample, we find general agreement but we detect an average overestimation bias of 0.23 dex in the KIC determination of log (g) for stars with log (g){sub KIC} > 4.0 dex, and a resultant underestimation bias of up to 50% in the KIC radii estimates for stars with R{sub KIC} < 2 R{sub sun}. Part of the difference may arise from selection bias in the asteroseismic sample; nevertheless, this result implies there may be fewer stars characterized in the KIC with R {approx} 1 R{sub sun} than is suggested by the physical properties in the KIC. Furthermore, if the radius estimates are taken from the KIC for these affected stars and then used to calculate the size of transiting planets, a similar underestimation bias may be applied to the planetary radii.

Verner, G. A.; Chaplin, W. J.; Elsworth, Y. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Basu, S. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Brown, T. M. [Las Cumbres Observatory Global Telescope, Goleta, CA 93117 (United States); Hekker, S. [Astronomical Institute, 'Anton Pannekoek', University of Amsterdam, P.O. Box 94249, 1090 GE Amsterdam (Netherlands); Huber, D.; Bedding, T. R. [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia); Karoff, C.; Bruntt, H.; Handberg, R. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Mathur, S.; Metcalfe, T. S. [High Altitude Observatory and Scientific Computing Division, National Center for Atmospheric Research, Boulder, CO 80307 (United States); Mosser, B. [LESIA, CNRS, Universite Pierre et Marie Curie, Universite Denis Diderot, Observatoire de Paris, 92195 Meudon Cedex (France); Quirion, P.-O. [Canadian Space Agency, 6767 Boulevard de l'Aeroport, Saint-Hubert, QC, J3Y 8Y9 (Canada); Appourchaux, T. [Institut d'Astrophysique Spatiale, Universite Paris XI - CNRS (UMR8617), Batiment 121, 91405 Orsay Cedex (France); Campante, T. L. [Centro de Astrofisica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); GarcIa, R. A. [Laboratoire AIM, CEA/DSM, CNRS, Universite Paris Diderot, IRFU/SAp, 91191 Gif-sur-Yvette Cedex (France); Regulo, C. [Departamento de Astrofisica, Universidad de La Laguna, E-38206 La Laguna, Tenerife (Spain); Roxburgh, I. W. [Astronomy Unit, Queen Mary, University of London, Mile End Road, London, E1 4NS (United Kingdom)

2011-09-10T23:59:59.000Z

99

The Nature and Orbit of the Ophiuchus Stream  

E-Print Network [OSTI]

The Ophiuchus stream is the most recently discovered stellar tidal stream in the Milky Way (Bernard et al. 2014). We present high-quality spectroscopic data for 14 stream member stars obtained using the Keck and MMT telescopes. We confirm the stream as a fast moving ($v_{los}\\sim290$ km s$^{-1}$), kinematically-cold group ($\\sigma_{v_{los}}\\lesssim1$ km s$^{-1}$) of $\\alpha-$enhanced and metal-poor stars (${\\rm [\\alpha/Fe]\\sim0.4}$ dex, ${\\rm [Fe/H]\\sim-2.0}$ dex). Using a probabilistic technique, we model the stream simultaneously in line-of-sight velocity, color-magnitude, coordinate, and proper motion space, and so determine its distribution in 6D phase-space. We find that that the stream extends in distance from 8 to 9.5 kpc from the Sun; it is 50 times longer than wide, merely appearing highly foreshortened in projection. The analysis of the stellar population contained in the stream suggests that it is $\\sim13$ Gyr old, and that its initial stellar mass was $\\sim2\\times10^4$ $M_\\sun$ (or at least $\\ga4\\...

Sesar, B; Bernard, E J; Caldwell, N; Cohen, J G; Fouesneau, M; Johnson, C I; Ness, M; Ferguson, A M N; Martin, N F; Rix, H -W; Schlafly, E F; Burgett, W S; Chambers, K C; Flewelling, H; Hodapp, K W; Kaiser, N; Magnier, E A; Platais, I; Tonry, J L; Waters, C; Wyse, R F G

2015-01-01T23:59:59.000Z

100

Permitted Oxygen Abundances and the Temperature Scale of Metal-Poor Turn-Off Stars  

E-Print Network [OSTI]

We use high quality VLT/UVES published data of the permitted OI triplet and FeII lines to determine oxygen and iron abundances in unevolved (dwarfs, turn-off, subgiants) metal-poor halo stars. The calculations have been performed both in LTE and NLTE, employing effective temperatures obtained with the new infrared flux method (IRFM) temperature scale by Ramirez & Melendez, and surface gravities from Hipparcos parallaxes and theoretical isochrones. A new list of accurate transition probabilities for FeII lines, tied to the absolute scale defined by laboratory measurements, has been used. We find a plateau in the oxygen-to-iron ratio over more than two orders of magnitude in iron abundance (-3.2 < [Fe/H] < -0.7), with a mean [O/Fe] = 0.5 dex (sigma = 0.1 dex), independent of metallicity, temperature and surface gravity. According to the new IRFM Teff scale, the temperatures of turn-off halo stars strongly depend on metallicity, a result that is in excellent qualitative and quantitative agreement with stellar evolution calculations, which predict that the Teff of the turn-off at [Fe/H] = -3 is about 600-700 K higher than that at [Fe/H] = -1.

J. Melendez; N. G. Shchukina; I. E. Vasiljeva; I. Ramirez

2006-01-12T23:59:59.000Z

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101

The solar oxygen crisis: Probably not the last word  

E-Print Network [OSTI]

In this work we present support for recent claims that advocate a downward revision of the solar oxygen abundance. Our analysis employs spatially-resolved spectro-polarimetric observations including the \\FeI lines at 6302 \\AA and the \\OI infrared triplet around 7774 \\AA in the quiet Sun. We used the \\FeI lines to reconstruct the three-dimensional thermal and magnetic structure of the atmosphere. The simultaneous \\OI observations were then employed to determine the abundance of oxygen at each pixel, using both LTE and non-LTE (NLTE) approaches to the radiative transfer. In this manner, we obtain values of \\lgEO=8.63 (NLTE) and 8.93 (LTE) dex. We find an unsettling fluctuation of the oxygen abundance over the field of view. This is likely an artifact indicating that, even with this relatively refined strategy, important physical ingredients are still missing in the picture. By examining the spatial distribution of the abundance, we estimate realistic confidence limits of approximately 0.1 dex.

H. Socas-Navarro A. A. Norton

2007-02-06T23:59:59.000Z

102

The Optical Gravitational Lensing Experiment. Red Clump Stars as a Distance Indicator  

E-Print Network [OSTI]

We present relation of the mean I-band brightness of red clump stars on metallicity. Red clump stars were proposed to be a very attractive standard candle for distance determination. The calibration is based on 284 nearby red giant stars whose high quality spectra allowed to determine accurate individual metal abundances. High quality parallaxes (\\sigma_\\pi / \\pi < 10%) and photometry of these very bright stars come from Hipparcos measurements. Metallicity of the sample covers a large range: -0.6<[Fe/H]<+0.2 dex. We find a weak dependence of the mean I-band brightness on metallicity (about 0.13 mag/dex). What is more important, the range of metallicity of the Hipparcos sample partially overlaps with metallicity of field giants in the LMC, thus making it possible to determine the distance to the LMC by almost direct comparison of brightness of the local Hipparcos red clump giants with that of LMC stars. Photometry of field red clump giants in nine low extinction fields of the LMC halo collected during the OGLE-II microlensing survey compared with the Hipparcos red clump stars data yields the distance modulus to the LMC: (m-M)_LMC=18.24+/-0.08 mag.

A. Udalski

2000-01-14T23:59:59.000Z

103

Accurate parameters of 93 solar-type Kepler targets  

E-Print Network [OSTI]

We present a detailed spectroscopic study of 93 solar-type stars that are targets of the NASA/Kepler mission and provide detailed chemical composition of each target. We find that the overall metallicity is well-represented by Fe lines. Relative abundances of light elements (CNO) and alpha-elements are generally higher for low-metallicity stars. Our spectroscopic analysis benefits from the accurately measured surface gravity from the asteroseismic analysis of the Kepler light curves. The log g parameter is known to better than 0.03 dex and is held fixed in the analysis. We compare our Teff determination with a recent colour calibration of V-K (TYCHO V magnitude minus 2MASS Ks magnitude) and find very good agreement and a scatter of only 80 K, showing that for other nearby Kepler targets this index can be used. The asteroseismic log g values agree very well with the classical determination using Fe1-Fe2 balance, although we find a small systematic offset of 0.08 dex (asteroseismic log g values are lower). The ...

Bruntt, H; Smalley, B; Chaplin, W J; Verner, G A; Bedding, T R; Catala, C; Gazzano, J -C; Molenda-Zakowicz, J; Thygesen, A O; Uytterhoeven, K; Hekker, S; Huber, D; Karoff, C; Mathur, S; Mosser, B; Appourchaux, T; Campante, T L; Elsworth, Y; Garcia, R A; Handberg, R; Metcalfe, T S; Quirion, P -O; Regulo, C; Roxburgh, I W; Stello, D; Christensen-Dalsgaard, J; Kawaler, S D; Kjeldsen, H; Morris, R L; Quintana, E V; Sanderfer, D T

2012-01-01T23:59:59.000Z

104

THE CHEMICAL EVOLUTION OF STAR-FORMING GALAXIES OVER THE LAST 11 BILLION YEARS  

SciTech Connect (OSTI)

We calculate the stellar mass-metallicity relation at five epochs ranging to z {approx} 2.3. We quantify evolution in the shape of the mass-metallicity relation as a function of redshift; the mass-metallicity relation flattens at late times. There is an empirical upper limit to the gas-phase oxygen abundance in star-forming galaxies that is independent of redshift. From examination of the mass-metallicity relation and its observed scatter, we show that the flattening at late times is a consequence of evolution in the stellar mass where galaxies enrich to this empirical upper metallicity limit; there is also evolution in the fraction of galaxies at a fixed stellar mass that enrich to this limit. The stellar mass where metallicities begin to saturate is {approx}0.7 dex smaller in the local universe than it is at z {approx} 0.8.

Zahid, H. Jabran; Kewley, Lisa J. [Institute for Astronomy, University of Hawaii at Manoa, 2680 Woodlawn Dr., Honolulu, HI 96822 (United States); Geller, Margaret J.; Hwang, Ho Seong; Fabricant, Daniel G.; Kurtz, Michael J. [Smithsonian Astrophysical Observatory, 60 Garden St., Cambridge, MA 02138 (United States)

2013-07-10T23:59:59.000Z

105

What Is The Neon Abundance Of The Sun?  

E-Print Network [OSTI]

We have evolved a series of thirteen complete solar models that utilize different assumed heavy element compositions. Models that are based upon the heavy element abundances recently determined by Asplund, Grevesse, and Sauval (2005) are inconsistent with helioseismological measurements. However, models in which the neon abundance is increased by 0.4-0.5 dex to log N(Ne) = 8.29 +- 0.05 (on the scale in which log N(H) = 12) are consistent with the helioseismological measurements even though the other heavy element abundances are in agreement with the determinations of Asplund et al. (2005). These results sharpen and strengthen an earlier study by Antia and Basu (2005). The predicted solar neutrino fluxes are affected by the uncertainties in the composition by less than their 1sigma theoretical uncertainties.

John N. Bahcall; Sarbani Basu; Aldo M. Serenelli

2005-05-16T23:59:59.000Z

106

Internal Dynamics, Structure and Formation of Dwarf Elliptical Galaxies: II. Rotating Versus Non-Rotating Dwarfs  

E-Print Network [OSTI]

We present spatially-resolved internal kinematics and stellar chemical abundances for a sample of dwarf elliptical (dE) galaxies in the Virgo Cluster observed with Keck/ESI. We find that 4 out of 17 dEs have major axis rotation velocities consistent with rotational flattening, while the remaining dEs have no detectable major axis rotation. Despite this difference in internal kinematics, rotating and non-rotating dEs are remarkably similar in terms of their position in the Fundamental Plane, morphological structure, stellar populations, and local environment. We present evidence for faint underlying disks and/or weak substructure in a fraction of both rotating and non-rotating dEs, but a comparable number of counter-examples exist for both types which show no evidence of such structure. Absorption-line strengths were determined based on the Lick/IDS system (Hbeta, Mgb, Fe5270, Fe5335) for the central region of each galaxy. We find no difference in the line-strength indices, and hence stellar populations, between rotating and non-rotating dE galaxies. The best-fitting mean age and metallicity for our 17 dE sample are 5 Gyr and Fe/H = -0.3 dex, respectively, with rms spreads of 3 Gyr and 0.1 dex. The majority of dEs are consistent with solar alpha/Fe abundance ratios. By contrast, the stellar populations of classical elliptical galaxies are, on average, older, more metal rich, and alpha-enhanced relative to our dE sample. The local environments of both dEs types appear to be diverse in terms of their proximity to larger galaxies in real or velocity space within the Virgo Cluster. Thus, rotating and non-rotating dEs are remarkably similar in terms of their structure, stellar content, and local environments, presenting a significant challenge to theoretical models of their formation. (abridged)

M. Geha; P. Guhathakurta; R. van der Marel

2003-06-17T23:59:59.000Z

107

Condensation temperature trends among stars with planets  

E-Print Network [OSTI]

Results from detailed spectroscopic analyses of stars hosting massive planets are employed to search for trends between abundances and condensation temperatures. The elements C, S, Na, Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Ni and Zn are included in the analysis of 64 stars with planets and 33 comparison stars. No significant trends are evident in the data. This null result suggests that accretion of rocky material onto the photospheres of stars with planets is not the primary explanation for their high metallicities. However, the differences between the solar photospheric and meteoritic abundances do display a weak but significant trend with condensation temperature. This suggests that the metallicity of the sun's envelope has been enriched relative to its interior by about 0.07 dex.

Guillermo Gonzalez

2005-12-08T23:59:59.000Z

108

A PRELIMINARY CALIBRATION OF THE RR LYRAE PERIOD-LUMINOSITY RELATION AT MID-INFRARED WAVELENGTHS: WISE DATA  

SciTech Connect (OSTI)

Using time-resolved, mid-infrared data from the Wide-field Infrared Survey Explorer (WISE) and geometric parallaxes from the Hubble Space Telescope for four Galactic RR Lyrae variables, we derive the following Population II period-luminosity (PL) relations for the WISE [W1], [W2], and [W3] bands at 3.4, 4.6, and 12 ?m, respectively: The slopes and the scatter around the fits are consistent with a smooth extrapolation of those same quantities from previously published K-band observations at 2.2 ?m, where the asymptotic (long-wavelength) behavior is consistent with a period-radius relation with a slope of 0.5. No obvious correlation with metallicity (spanning 0.4 dex in [Fe/H]) is found in the residuals of the four calibrating RR Lyrae stars about the mean PL regression line.

Madore, Barry F.; Freedman, Wendy L.; Kollmeier, Juna A.; Monson, Andy; Eric Persson, S.; Rich, Jeff A. Jr.; Scowcroft, Victoria; Seibert, Mark [Observatories of the Carnegie Institution of Washington 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Hoffman, Douglas, E-mail: barry@obs.carnegiescience.edu, E-mail: wendy@obs.carnegiescience.edu, E-mail: jak@obs.carnegiescience.edu, E-mail: amonson@obs.carnegiescience.edu, E-mail: persson@obs.carnegiescience.edu, E-mail: jrich@obs.carnegiescience.edu, E-mail: vs@obs.carnegiescience.edu, E-mail: mseibert@obs.carnegiescience.edu [Infrared Processing and Analysis Center 770 South Wilson, Pasadena, CA 91125 (United States)

2013-10-20T23:59:59.000Z

109

CALIBRATIONS OF ATMOSPHERIC PARAMETERS OBTAINED FROM THE FIRST YEAR OF SDSS-III APOGEE OBSERVATIONS  

SciTech Connect (OSTI)

The Sloan Digital Sky Survey III (SDSS-III) Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a three-year survey that is collecting 10{sup 5} high-resolution spectra in the near-IR across multiple Galactic populations. To derive stellar parameters and chemical compositions from this massive data set, the APOGEE Stellar Parameters and Chemical Abundances Pipeline (ASPCAP) has been developed. Here, we describe empirical calibrations of stellar parameters presented in the first SDSS-III APOGEE data release (DR10). These calibrations were enabled by observations of 559 stars in 20 globular and open clusters. The cluster observations were supplemented by observations of stars in NASA's Kepler field that have well determined surface gravities from asteroseismic analysis. We discuss the accuracy and precision of the derived stellar parameters, considering especially effective temperature, surface gravity, and metallicity; we also briefly discuss the derived results for the abundances of the ?-elements, carbon, and nitrogen. Overall, we find that ASPCAP achieves reasonably accurate results for temperature and metallicity, but suffers from systematic errors in surface gravity. We derive calibration relations that bring the raw ASPCAP results into better agreement with independently determined stellar parameters. The internal scatter of ASPCAP parameters within clusters suggests that metallicities are measured with a precision better than 0.1 dex, effective temperatures better than 150 K, and surface gravities better than 0.2 dex. The understanding provided by the clusters and Kepler giants on the current accuracy and precision will be invaluable for future improvements of the pipeline.

Mszros, Sz.; Allende Prieto, C. [Instituto de Astrofsica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Holtzman, J. [New Mexico State University, Las Cruces, NM 88003 (United States); Garca Prez, A. E.; Chojnowski, S. D.; Hearty, F. R.; Majewski, S. R. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Schiavon, R. P. [Astrophysics Research Institute, Liverpool John Moores University, Egerton Wharf, Birkenhead, Wirral CH41 1LD (United Kingdom); Basu, S. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Bizyaev, D. [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349-0059 (United States); Chaplin, W. J.; Elsworth, Y. [University of Birmingham, School of Physics and Astronomy, Edgbaston, Birmingham B15 2TT (United Kingdom); Cunha, K. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Epstein, C.; Johnson, J. A. [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States); Frinchaboy, P. M. [Texas Christian University, Fort Worth, TX 76129 (United States); Garca, R. A. [Laboratoire AIM, CEA/DSM-CNRS-Universit Paris Diderot, IRFU/SAp, Centre de Saclay, F-91191 Gif-sur-Yvette Cedex (France); Hekker, S. [Astronomical Institute ''Anton Pannekoek'', University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); Kallinger, T. [Institute for Astronomy, University of Vienna, Trkenschanzstrasse 17, A-1180 Vienna (Austria); Koesterke, L. [Texas Advanced Computing Center, University of Texas, Austin, TX 78759 (United States); and others

2013-11-01T23:59:59.000Z

110

The chemical abundances of the Ap star HD94660  

SciTech Connect (OSTI)

In this work I present the determination of chemical abundances of the Ap star HD94660, a possible rapid oscillating star. As all the magnetic chemically peculiar objects, it presents CNO underabundance and overabundance of iron peak elements of ?100 times and of rare earths up to 4 dex with respect to the Sun. The determination was based on the conversion of the observed equivalent widths into abundances simultaneously to the determination of effective temperature and gravity. Since the Balmer lines of early type stars are very sensitive to the surface gravity while the flux distribution is sensitive to the effective temperature, I have adopted an iterative procedure to match the H{sub ?} line profile and the observed UV-Vis-NIR magnitudes of HD94660 looking for a consistency between the metallicity of the atmosphere model and the derived abundances. From my spectroscopic analysis, this star belongs to the no-rapid oscillating class.

Giarrusso, M. [Universit di Catania, Dipartimento di Fisica e Astronomia, Sezione Astrofisica, Via S. Sofia 78, 95123 Catania (Italy); INAF - Osservatorio Astrofisico di Catania, via S. Sofia 78, 95123 Catania (Italy); INFN - Laboratori Nazionali del Sud (Italy)

2014-05-09T23:59:59.000Z

111

Lithium Depletion of Nearby Young Stellar Associations  

E-Print Network [OSTI]

We estimate cluster ages from lithium depletion in five pre-main-sequence groups found within 100 pc of the Sun: TW Hydrae Association, Eta Chamaeleontis Cluster, Beta Pictoris Moving Group, Tucanae-Horologium Association and AB Doradus Moving Group. We determine surface gravities, effective temperatures and lithium abundances for over 900 spectra through least squares fitting to model-atmosphere spectra. For each group, we compare the dependence of lithium abundance on temperature with isochrones from pre-main-sequence evolutionary tracks to obtain model dependent ages. We find that the Eta Chamaelontis Cluster and the TW Hydrae Association are the youngest, with ages of 12+/-6 Myr and 12+/-8 Myr, respectively, followed by the Beta Pictoris Moving Group at 21+/-9 Myr, the Tucanae-Horologium Association at 27+/-11 Myr, and the AB Doradus Moving Group at an age of at least 45 Myr (where we can only set a lower limit since the models -- unlike real stars -- do not show much lithium depletion beyond this age). Here, the ordering is robust, but the precise ages depend on our choice of both atmospheric and evolutionary models. As a result, while our ages are consistent with estimates based on Hertzsprung-Russell isochrone fitting and dynamical expansion, they are not yet more precise. Our observations do show that with improved models, much stronger constraints should be feasible: the intrinsic uncertainties, as measured from the scatter between measurements from different spectra of the same star, are very low: around 10 K in effective temperature, 0.05 dex in surface gravity, and 0.03 dex in lithium abundance.

Erin Mentuch; Alexis Brandeker; Marten H. van Kerkwijk; Ray Jayawardhana; Peter H. Hauschildt

2008-08-26T23:59:59.000Z

112

A NEW SYNTHETIC LIBRARY OF THE NEAR-INFRARED Ca II TRIPLET INDICES. I. INDEX DEFINITION, CALIBRATION, AND RELATIONS WITH STELLAR ATMOSPHERIC PARAMETERS  

SciTech Connect (OSTI)

Adopting the SPECTRUM package, which is a stellar spectral synthesis program, we have synthesized a comprehensive set of 2890 near-infrared (NIR) synthetic spectra with a resolution and wavelength sampling similar to the Sloan Digital Sky Survey (SDSS) and the forthcoming Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) spectra. During the synthesis, we applied the 'New grids of ATLAS9 Model Atmosphere' to develop a grid of local thermodynamic equilibrium model atmospheres for effective temperatures (T{sub eff}) ranging from 3500 to 7500 K, for surface gravities (log g) from 0.5 to 5.0 dex, for metallicities ([Fe/H]) from -4.0 to 0.5 dex, and for solar ([{alpha}/Fe] = 0.0 dex) and non-solar ([{alpha}/Fe] = +0.4 dex) abundances. This synthetic stellar library is composed of 1350 solar scaled abundance (SSA) and 1530 non-solar scaled abundance (NSSA) spectra, grounding on which we have defined a new set of NIR Ca II triplet indices and an index CaT as the sum of the three. These defined indices were automatically measured on every spectrum of the synthetic stellar library and calibrated with the indices computed on the observational spectra from the INDO-U.S. stellar library. In order to check the effect of {alpha}-element enhancement on the so-defined Ca II indices, we compared indices measured on the SSA spectra with those on the NSSA ones at the same trine of stellar parameters (T{sub eff}, log g, [Fe/H]); luckily, little influences of {alpha}-element enhancement were found. Furthermore, comparisons of our synthetic indices with the observational ones from measurements on the INDO-U.S. stellar library, the SDSS-DR7 and SDSS-DR8 spectroscopic survey are presented, respectively, for dwarfs and giants in specific. For dwarfs, our synthetic indices could well reproduce the behaviors of the observational indices versus stellar parameters, which verifies the validity of our index definitions for dwarfs. For giants, the consistency between our synthetic indices and the observational ones does not appear to be as good. However, a new synthetic library of NIR Ca II indices has been founded for deeper studies on the NIR wave band of stellar spectra, and this library is particularly appropriate for the SDSS and the forthcoming LAMOST stellar spectra. We have regressed the strength of the CaT index as a function of stellar parameters for both dwarfs and giants after a series of experimental investigations into relations of the indices with stellar parameters. For dwarfs, log g has little effect on the indices, while [Fe/H] and T{sub eff} play a role together. The leading factor is probably [Fe/H], which changes the strength of the indices by a positive trend. For giants, log g starts to influence the strength of the indices by a negative trend for the metal-poor, and even impact deeply for the metal-rich; besides, [Fe/H] and T{sub eff} still matter. In addition, we briefly discussed the major differences between our Ca II triplet indices and the CaHK doublet indices. Ultimately, a supplemental experiment was carried out to show that spectral noises do have effects on our set of NIR Ca II indices. However, the influence is not weak enough to be ignored if the signal-to-noise ratio falls below 20.

Du, W.; Luo, A. L.; Zhao, Y. H., E-mail: wdu@nao.cas.cn, E-mail: lal@nao.cas.cn [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

2012-02-15T23:59:59.000Z

113

A NEW CEPHEID DISTANCE TO THE GIANT SPIRAL M101 BASED ON IMAGE SUBTRACTION OF HUBBLE SPACE TELESCOPE/ADVANCED CAMERA FOR SURVEYS OBSERVATIONS  

SciTech Connect (OSTI)

We accurately determine a new Cepheid distance to M101 (NGC 5457) using archival Hubble Space Telescope (HST)/Advanced Camera for Surveys V and I time series photometry of two fields within the galaxy. We make a slight modification to the ISIS image subtraction package to obtain optimal differential light curves from HST data. We discovered 827 Cepheids with periods between 3 and 80 days, the largest extragalactic sample of Cepheids observed with HST by a factor of two. With this large Cepheid sample, we find that the relative distance of M101 from the Large Magellanic Cloud is {Delta}{mu}{sub LMC} = 10.63 {+-} 0.04 (random) {+-} 0.06 (systematic) mag. If we use the geometrically determined maser distance to NGC 4258 as our distance anchor, the distance modulus of M101 is {mu}{sub 0} = 29.04 {+-} 0.05 (random) {+-} 0.18 (systematic) mag or D = 6.4 {+-} 0.2 (random) {+-} 0.5 (systematic) Mpc. The uncertainty is dominated by the maser distance estimate ({+-}0.15 mag), which should improve over the next few years. We determine a steep metallicity dependence, {gamma}, for our Cepheid sample through two methods, yielding {gamma} = -0.80 {+-} 0.21 (random) {+-} 0.06 (systematic) mag dex{sup -1} and {gamma} = -0.72{sup +0.22}{sub -0.25} (random) {+-} 0.06 (systematic) mag dex{sup -1}. We see marginal evidence for variations in the Wesenheit period-luminosity relation slope as a function of deprojected galactocentric radius. We also use the tip of the red giant branch method to independently determine the distance modulus to M101 of {mu}{sub 0} = 29.05 {+-} 0.06 (random) {+-} 0.12 (systematic) mag.

Shappee, Benjamin J.; Stanek, K. Z., E-mail: shappee@astronomy.ohio-state.edu, E-mail: kstanek@astronomy.ohio-state.edu [Department of Astronomy, Ohio State University, Columbus, OH 43210 (United States)

2011-06-01T23:59:59.000Z

114

A spectroscopic confirmation of the Bootes II dwarf spheroidal  

E-Print Network [OSTI]

We present a new suite of photometric and spectroscopic data for the faint Bootes II dwarf spheroidal galaxy candidate. Our deep photometry, obtained with the INT/WFC, suggests a distance of 46 kpc and a small half-light radius of 4.0 arcmin (56 pc), consistent with previous estimates. Follow-up spectroscopy obtained with the Gemini/GMOS instrument yielded radial velocities and metallicities. While the majority of our targets covers a broad range in velocities and metallicities, we find five stars which share very similar velocities and metallicities and which are all compatible with the colors and magnitudes of the galaxy's likely red giant branch. We interpret these as a spectroscopic detection of the Bootes II system. These stars have a mean velocity of -117 km/s, a velocity dispersion of (10.5+-7.4) km/s and a mean [Fe/H] of -1.79 dex, with a dispersion of 0.14 dex. At this metallicity, Boo II is not consistent with the stellar-mass-metallicity relation for the more luminous dwarf galaxies. Coupled with our distance estimate, its high negative systemic velocity rules out any physical connection with its projected neighbor, the Bootes I dwarf spheroidal, which has a velocity of ~+100 km/s. The velocity and distance of Bootes II coincide with those of the leading arm of Sagittarius, which passes through this region of the sky, so that it is possible that Bootes II may be a stellar system associated with the Sagittarius stream. Finally, we note that the properties of Bootes II are consistent with being the surviving remnant of a previously larger and more luminous dSph galaxy.

A. Koch; M. I. Wilkinson; J. T. Kleyna; M. Irwin; D. B. Zucker; V. Belokurov; G. F. Gilmore; M. Fellhauer; N. W. Evans

2008-09-03T23:59:59.000Z

115

Descriptive logs, skeletonized samples, and photographs of core...  

Open Energy Info (EERE)

dex.php?titleDescriptivelogs,skeletonizedsamples,andphotographsofcorefromPrescoEnergy%27sthermalgradientwellsP3-1,P10-1,andP32-2intheRyePatcharea,PershingC...

116

Type-Ia Supernova Remnant Shell At $Z=3.5$ Seen In The Three Sightlines Toward The Gravitationally Lensed Qso B1422+231  

E-Print Network [OSTI]

Using the Subaru 8.2m Telescope with an IRCS Echelle spectrograph, we obtained high-resolution (R=10,000) near-infrared (1.01-1.38 \\mu m) spectra of images A and B of the gravitationally lensed QSO B1422+231 (z=3.628) consisting of four known lensed images. We detected MgII absorption lines at z=3.54, which show a large variance of column densities (~ 0.3 dex) and velocities (~ 10 km/s) between the sightlines A and B with a projected separation of only 8.4h_{70}^{-1} pc at the redshift. This is the smallest spatial structure of the high-z gas clouds ever detected after Rauch et al. found a 20-pc scale structure for the same z=3.54 absorption system using optical spectra of images A and C. The observed systematic variances imply that the system is an expanding shell as originally suggested by Rauch et al. By combining the data for three sightlines, we managed to constrain the radius and expansion velocity of the shell (~ 50-100 pc, 130 km/s), concluding that the shell is truly a supernova remnant (SNR) rather ...

Hamano, Satoshi; Kondo, Sohei; Tsujimoto, Takuji; Okoshi, Katsuya; Shigeyama, Toshikazu

2012-01-01T23:59:59.000Z

117

Density Ratio Estimation: A Comprehensive Review Masashi Sugiyama, Tokyo Institute of Technology (sugi@cs.titech.ac.jp)  

E-Print Network [OSTI]

.i.d.) samples {xnu i }nnu i=1 from a distribution with density p nu(x) and i.i.d. samples {xde j }nde j=1 from another distribution with density p de(x). {xnu i }nnu i=1 i.i.d. p nu(x) and {xde j }nde j=1 i.i.d. p the density ratio r (x) := p nu(x) p de(x) from samples {xnu i }nnu i=1 and {xde j }nde j=1. `nu' and `de

Sugiyama, Masashi

118

On the maximum value of the cosmic abundance of oxygen and the oxygen yield  

E-Print Network [OSTI]

We search for the maximum oxygen abundance in spiral galaxies. Because this maximum value is expected to occur in the centers of the most luminous galaxies, we have constructed the luminosity - central metallicity diagram for spiral galaxies, based on a large compilation of existing data on oxygen abundances of HII regions in spiral galaxies. We found that this diagram shows a plateau at high luminosities (-22.3 oxygen abundance 12+log(O/H) ~ 8.87. This provides strong evidence that the oxygen abundance in the centers of the most luminous metal-rich galaxies reaches the maximum attainable value of oxygen abundance. Since some fraction of the oxygen (about 0.08 dex) is expected to be locked into dust grains, the maximum value of the true gas+dust oxygen abundance in spiral galaxies is 12+log(O/H) ~ 8.95. This value is a factor of ~ 2 higher than the recently estimated solar value. Based on the derived maximum oxygen abundance in galaxies, we found the oxygen yield to be about 0.0035, depending on the fraction of oxygen incorporated into dust grains.

L. S. Pilyugin; T. X. Thuan; J. M. Vilchez

2007-01-11T23:59:59.000Z

119

USING CUMULATIVE NUMBER DENSITIES TO COMPARE GALAXIES ACROSS COSMIC TIME  

SciTech Connect (OSTI)

Comparing galaxies across redshifts at fixed cumulative number density is a popular way to estimate the evolution of specific galaxy populations. This method ignores scatter in mass accretion histories and galaxy-galaxy mergers, which can lead to errors when comparing galaxies over large redshift ranges (?z > 1). We use abundance matching in the ?CDM paradigm to estimate the median change in cumulative number density with redshift and provide a simple fit (+0.16 dex per unit ?z) for progenitors of z = 0 galaxies. We find that galaxy descendants do not evolve in the same way as galaxy progenitors, largely due to scatter in mass accretion histories. We also provide estimates for the 1? range of cumulative number densities corresponding to galaxy progenitors and descendants. Finally, we discuss some limits on cumulative number density comparisons, which arise due to difficulties measuring physical quantities (e.g., stellar mass) consistently across redshifts. A public tool to calculate cumulative number density evolution for galaxies, as well as approximate halo masses, is available online.

Behroozi, Peter S.; Wechsler, Risa H. [Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Stanford, CA 94305 (United States)] [Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Stanford, CA 94305 (United States); Marchesini, Danilo [Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States)] [Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States); Muzzin, Adam [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)] [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Papovich, Casey [Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States)] [Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Stefanon, Mauro [Physics and Astronomy Department, University of Missouri, Columbia, MO 65211 (United States)] [Physics and Astronomy Department, University of Missouri, Columbia, MO 65211 (United States)

2013-11-01T23:59:59.000Z

120

Improved HCN/HNC linelist, model atmospheres and synthetic spectra for WZ Cas  

E-Print Network [OSTI]

We build an accurate database of 5200 HCN and HNC rotation-vibration energy levels, determined from existing laboratory data. 20~000 energy levels in the Harris et al. (2002) linelist are assigned approximate quantum numbers. These assignments, lab determined energy levels and Harris et al (2002) energy levels are incorporated in to a new energy level list. A new linelist is presented, in which frequencies are computed using the lab determined energy levels where available, and the ab initio energy levels otherwise. The new linelist is then used to compute new model atmospheres and synthetic spectra for the carbon star WZ Cas. This results in better fit to the spectrum of WZ Cas in which the absorption feature at 3.56 micron is reproduced to a higher degree of accuracy than has previously been possible. We improve the reproduction of HCN absorption features by reducing the abundance of Si to [Si/H] = --0.5 dex, however, the strengths of the $\\Delta v=2$ CS band heads are over-predicted.

G. J. Harris; J. Tennyson; B. M. Kaminsky; Ya. V. Pavlenko; H. R. A. Jones

2005-12-14T23:59:59.000Z

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to obtain the most current and comprehensive results.


121

Ground-based observations of the beta Cephei CoRoT main target HD 180642: abundance analysis and mode identification  

E-Print Network [OSTI]

The known beta Cephei star HD 180642 was observed by the CoRoT satellite in 2007. From the very high-precision light curve, its pulsation frequency spectrum could be derived for the first time (Degroote and collaborators). In this paper, we obtain additional constraints for forthcoming asteroseismic modeling of the target. Our results are based on both extensive ground-based multicolour photometry and high-resolution spectroscopy. We determine T_eff = 24 500+-1000 K and log g = 3.45+-0.15 dex from spectroscopy. The derived chemical abundances are consistent with those for B stars in the solar neighbourhood, except for a mild nitrogen excess. A metallicity Z = 0.0099+-0.0016 is obtained. Three modes are detected in photometry. The degree l is unambiguously identified for two of them: l = 0 and l = 3 for the frequencies 5.48694 1/d and 0.30818 1/d, respectively. The radial mode is non-linear and highly dominant with an amplitude in the U-filter about 15 times larger than the strongest of the other modes. For th...

Briquet, M; Morel, T; Aerts, C; De Cat, P; Mathias, P; Lefever, K; Miglio, A; Poretti, E; Martin-Ruiz, S; Paparo, M; Rainer, M; Carrier, F; Gutirrez-Soto, J; Valtier, J C; Benko, J M; Bognr, Z; Niemczura, E; Amado, P J; Surez, J C; Moya, A; Rodriguez-Lopez, C; Garrido, R

2009-01-01T23:59:59.000Z

122

Strontium: To LTE or non-LTE that is the question  

E-Print Network [OSTI]

Strontium has proven itself to be one of the most important neutron-capture elements in the study of metal-poor stars. Thanks to the strong absorption lines of Sr, they can be detected even in the most metal-poor stars and also in low-resolution spectra. However, we still cannot explain the large star-to-star abundance scatter we derive for metal-poor stars. Here we confront Galactic chemical evolution (GCE) with improved abundances for SrI+II including updated atomic data, to evaluate possible explanations for the large star-to-star scatter at low metallicities. We derive abundances under both local thermodynamic equilibrium (LTE) and non-LTE (NLTE) for stars spanning a large interval of stellar parameters. Gravities and metallicities are also determined in NLTE. We confirm that the ionisation equilibrium between SrI and SrII is satisfied under NLTE but not LTE, where the difference between SrI and SrII is on average ~0.3dex. We show that the NLTE corrections are of increasing importance as the metallicity d...

Hansen, Camilla J; Cescutti, Gabriele; Francois, Patrick; Arcones, Almudena; Karakas, Amanda I; Lind, Karin; Chiappini, Cristina

2012-01-01T23:59:59.000Z

123

Carbon and Strontium Abundances of Metal-Poor Stars  

E-Print Network [OSTI]

We present carbon and strontium abundances for 100 metal-poor stars measured from R$\\sim $7000 spectra obtained with the Echellette Spectrograph and Imager at the Keck Observatory. Using spectral synthesis of the G-band region, we have derived carbon abundances for stars ranging from [Fe/H]$=-1.3$ to [Fe/H]$=-3.8$. The formal errors are $\\sim 0.2$ dex in [C/Fe]. The strontium abundance in these stars was measured using spectral synthesis of the resonance line at 4215 {\\AA}. Using these two abundance measurments along with the barium abundances from our previous study of these stars, we show it is possible to identify neutron-capture-rich stars with our spectra. We find, as in other studies, a large scatter in [C/Fe] below [Fe/H]$ = -2$. Of the stars with [Fe/H]$<-2$, 9$\\pm$4% can be classified as carbon-rich metal-poor stars. The Sr and Ba abundances show that three of the carbon-rich stars are neutron-capture-rich, while two have normal Ba and Sr. This fraction of carbon enhanced stars is consistent with other studies that include this metallicity range.

David K. Lai; Jennifer A. Johnson; Michael Bolte; Sara Lucatello

2007-06-20T23:59:59.000Z

124

An inefficient dwarf: Chemical abundances and the evolution of the Ursa Minor dwarf spheroidal galaxy  

E-Print Network [OSTI]

We present detailed chemical element abundance ratios of 17 elements in three metal poor stars in the Ursa Minor dwarf spheroidal galaxy, which we combine with extant data from the literature to assess the predictions of a novel suite of galaxy chemical evolution models. The spectroscopic data were obtained with the Keck/HIRES instrument and revealed low metallicities of [Fe/H]=-2.12, -2.13 and -2.67 dex. While the most metal poor star in our sample shows an overabundance of [Mn/Fe] and other Fe-peak elements, our overall findings are in agreement with previous studies of this galaxy: elevated values of the [alpha/Fe] ratios that are similar to, or only slightly lower than, the halo values but with SN Ia enrichment at very low metallicity, as well as an enhancement of the ratio of first to second peak neutron capture elements [Y/Ba] with decreasing metallicity. The chemical evolution models which were tailored to reproduce the metallicity distribution function of the dSph, indicate that UMi had an extended st...

Ural, Ugur; Koch, Andreas; Kleyna, Jan; Feltzing, Sofia; Wilkinson, Mark I

2015-01-01T23:59:59.000Z

125

Stellar Metallicity of the Extended Disk and Distance of the Spiral Galaxy NGC 3621  

E-Print Network [OSTI]

Low resolution ESO VLT/FORS spectra of blue supergiant stars are analyzed to determine stellar metallicities (based on elements such as Fe, Ti, Mg) in the extended disk of the spiral galaxy NGC3621. Mildly subsolar metallicity (-0.30 dex) is found for the outer objects beyond 7 kpc independent of galactocentric radius and compatible with the absence of a metallicity gradient confirming the results of a recent investigation of interstellar medium HII region gas oxygen abundances. The stellar metallicities are slightly higher than those from the HII regions when based on measurements of the weak forbidden auroral oxygen line at 4363 AE but lower than the ones obtained with the R23 strong line method. It is shown that the present level of metallicity in the extended disk cannot be the result of chemical evolution over the age of the disk with the present rate of in situ star formation. Additional mechanisms must be involved. In addition to metallicity, stellar effective temperatures, gravities, interstellar redd...

Kudritzki, Rolf-Peter; Bresolin, Fabio; Hosek, Matthew W; Przybilla, Norbert

2014-01-01T23:59:59.000Z

126

HOST GALAXY PROPERTIES AND HUBBLE RESIDUALS OF TYPE Ia SUPERNOVAE FROM THE NEARBY SUPERNOVA FACTORY  

SciTech Connect (OSTI)

We examine the relationship between Type Ia supernova (SN Ia) Hubble residuals and the properties of their host galaxies using a sample of 115 SNe Ia from the Nearby Supernova Factory. We use host galaxy stellar masses and specific star formation rates fitted from photometry for all hosts, as well as gas-phase metallicities for a subset of 69 star-forming (non-active galactic nucleus) hosts, to show that the SN Ia Hubble residuals correlate with each of these host properties. With these data we find new evidence for a correlation between SN Ia intrinsic color and host metallicity. When we combine our data with those of other published SN Ia surveys, we find the difference between mean SN Ia brightnesses in low- and high-mass hosts is 0.077 {+-} 0.014 mag. When viewed in narrow (0.2 dex) bins of host stellar mass, the data reveal apparent plateaus of Hubble residuals at high and low host masses with a rapid transition over a short mass range (9.8 {<=} log (M{sub *}/M{sub Sun }) {<=} 10.4). Although metallicity has been a favored interpretation for the origin of the Hubble residual trend with host mass, we illustrate how dust in star-forming galaxies and mean SN Ia progenitor age both evolve along the galaxy mass sequence, thereby presenting equally viable explanations for some or all of the observed SN Ia host bias.

Childress, M.; Aldering, G.; Aragon, C.; Bailey, S.; Fakhouri, H. K.; Hsiao, E. Y.; Kim, A. G.; Loken, S. [Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Antilogus, P.; Bongard, S.; Canto, A.; Cellier-Holzem, F.; Guy, J. [Laboratoire de Physique Nucleaire et des Hautes Energies, Universite Pierre et Marie Curie Paris 6, Universite Paris Diderot Paris 7, CNRS-IN2P3, 4 place Jussieu, F-75252 Paris Cedex 05 (France); Baltay, C. [Department of Physics, Yale University, New Haven, CT 06250-8121 (United States); Buton, C.; Kerschhaggl, M.; Kowalski, M. [Physikalisches Institut, Universitaet Bonn, Nussallee 12, D-53115 Bonn (Germany); Chotard, N.; Copin, Y.; Gangler, E. [Universite de Lyon, F-69622, Lyon (France); Universite de Lyon 1, Villeurbanne (France); CNRS/IN2P3, Institut de Physique Nucleaire de Lyon (France); and others

2013-06-20T23:59:59.000Z

127

Observational constraints on the progenitors of core-collapse supernovae : the case for missing high mass stars  

E-Print Network [OSTI]

Over the last 15 years, the supernova community has endeavoured to identify progenitor stars of core-collapse supernovae in high resolution archival images of their galaxies.This review compiles results (from 1999 - 2013) in a distance limited sample and discusses the implications. The vast majority of the detections of progenitor stars are of type II-P, II-L or IIb with one type Ib progenitor system detected and many more upper limits for progenitors of Ibc supernovae (14). The data for these 45 supernovae progenitors illustrate a remarkable deficit of high luminosity stars above an apparent limit of Log L ~= 5.1 dex. For a typical Salpeter IMF, one would expect to have found 13 high luminosity and high mass progenitors. There is, possibly, only one object in this time and volume limited sample that is unambiguously high mass (the progenitor of SN2009ip). The possible biases due to the influence of circumstellar dust and sample selection methods are reviewed. It does not appear likely that these can explain ...

Smartt, S J

2015-01-01T23:59:59.000Z

128

Two Super-Earths Orbiting the Solar Analogue HD41248 on the edge of a 7:5 Mean Motion Resonance  

E-Print Network [OSTI]

The number of multi-planet systems known to be orbiting their host stars with orbital periods that place them in mean motion resonances is growing. For the most part, these systems are in first-order resonances and dynamical studies have focused their efforts towards understanding the origin and evolution of such dynamically resonant commensurabilities. We report here the discovery of two super-Earths that are close to a second-order dynamical resonance, orbiting the metal-poor ([Fe/H]=-0.43 dex) and inactive G2V star HD41428. We analysed 62 HARPS archival radial velocities for this star, that until now, had exhibited no evidence for planetary companions. Using our new Bayesian Doppler signal detection algorithm, we find two significant signals in the data, with periods of 18.357 days and 25.648 days, indicating they could be part of a 7:5 second-order mean motion resonance. Both semi-amplitudes are below 3m/s and the minimum masses of the pair are 12.3 and 8.6Mearth, respectively. Our simulations found that ...

Jenkins, James S; Brasser, Ramon; Ivanyuk, Oleksiy; Murgas, Felipe

2013-01-01T23:59:59.000Z

129

Discovery of a peculiar Cepheid-like star towards the northern edge of the Small Magellanic Cloud  

E-Print Network [OSTI]

For seven years, the EROS-2 project obtained a mass of photometric data on variable stars. We present a peculiar Cepheid-like star, in the direction of the Small Magellanic Cloud, which demonstrates unusual photometric behaviour over a short time interval. We to report on data of the photometriy acquired by the MARLY telescope and spectroscopy from the EFOSC instrument for this star, called EROS2 J005135-714459(sm0060n13842), which resembles the unusual Cepheid HR 7308. The light curve of our target is analysed using the Analysis of Variance method to determine a pulsational period of 5.5675 days. A fit of time-dependent Fourier coefficients is performed and a search for proper motion is conducted. The light curve exhibits a previously unobserved and spectacular change in both mean magnitude and amplitude, which has no clear theoretical explanation. Our analysis of the spectrum implies a radial velocity of 104 km s$^{-1}$ and a metallicity of -0.4$\\pm$0.2 dex. In the direction of right ascension, we measure a...

Marquette, J B; Franois, P; Beaulieu, J P; Doublier, V; Lesquoy, E; Milsztajn, A; Pritchard, J; Schwarzenberg-Czerny, A; Afonso, C; Albert, J N; Andersen, J; Ansari, R; Aubourg, E; Bareyre, 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; Guillou, L Le; Loup, C; Magneville, C; Maurice, E; Maury, A; Moniez, M; Palanque-Delabrouille, Nathalie; Perdereau, O; Rahal, Y R; Rich, J; Spiro, M; Vidal-Madjar, A; Zylberajch, S

2008-01-01T23:59:59.000Z

130

THE RAVE CATALOG OF STELLAR ELEMENTAL ABUNDANCES: FIRST DATA RELEASE  

SciTech Connect (OSTI)

We present chemical elemental abundances for 36,561 stars observed by the RAdial Velocity Experiment (RAVE), an ambitious spectroscopic survey of our Galaxy at Galactic latitudes |b| > 25 Degree-Sign and with magnitudes in the range 9 dex, as judged from accuracy tests performed on synthetic and real spectra. Abundances are estimated through a dedicated processing pipeline in which the curve of growth of individual lines is obtained from a library of absorption line equivalent widths to construct a model spectrum that is then matched to the observed spectrum via a {chi}{sup 2} minimization technique. We plan to extend this pipeline to include estimates for other elements, such as oxygen and sulfur, in future data releases.

Boeche, C.; Williams, M.; De Jong, R. S.; Steinmetz, M. [Leibniz-Institut fuer Astrophysik Potsdam (AIP), D-14482 Potsdam (Germany); Siebert, A.; Bienayme, O. [Observatoire Astronomique de Strasbourg, Universite de Strasbourg, CNRS, UMR 7550, F-67000 Strasbourg (France); Fulbright, J. P.; Ruchti, G. R. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Bland-Hawthorn, J. [Sydney Institute for Astronomy, School of Physics A28, University of Sydney, NSW 2006 (Australia); Campbell, R. [Department of Physics and Astronomy, Western Kentucky University, Bowling Green, KY (United States); Freeman, K. C. [Research School of Astronomy and Astrophysics, Australia National University, Weston Creek, Canberra ACT 2611 (Australia); Gibson, B. K. [Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Gilmore, G. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Grebel, E. K. [Astronomisches Rechen-Institut, Zentrum fuer Astronomie der Universitaet Heidelberg, D-69120 Heidelberg (Germany); Helmi, A. [Kapteyn Astronomical Institute, University of Groningen, 9700 AV Groningen (Netherlands); Munari, U. [INAF Osservatorio Astronomico di Padova, Asiago I-36012 (Italy); Navarro, J. F. [Department of Physics and Astronomy, University of Victoria, Victoria BC V8W 3P6 (Canada); Parker, Q. A.; Reid, W. [Department of Physics and Astronomy, Faculty of Sciences, Macquarie University, Sydney, NSW 2109 (Australia); Seabroke, G. M. [Mullard Space Science Laboratory, University College London, Holmbury, St. Mary RH5 6NT (United Kingdom); and others

2011-12-15T23:59:59.000Z

131

Impact of the new solar abundances on the calibration of the PMS binary system RS Cha  

E-Print Network [OSTI]

Context: In a recent work, we tried to obtain a calibration of the two components of the pre-main sequence binary system RS Cha by means of theoretical stellar models. We found that the only way to reproduce the observational parameters of RS Cha with standard stellar models is to decrease the initial abundances of carbon and nitrogen derived from the GN93 solar mixture of heavy elements by a few tenths of dex. Aims: In this work, we aim to reproduce the observational properties of the RS Cha stars with stellar evolution models based on the new AGS05 solar mixture recently derived from a three-dimensional solar model atmosphere. The AGS05 mixture is depleted in carbon, nitrogen and oxygen with respect to the GN93 mixture. Methods: We calculated new stellar models of the RS Cha components using the AGS05 mixture and appropriate opacity tables. We sought models that simultaneously satisfy the observations of the two components (masses, radii, luminosities, effective temperatures and metallicity). Results: We fi...

Alecian, E; Goupil, M-J; Dupret, M-A; Catala, C

2007-01-01T23:59:59.000Z

132

Population Effects on the Metallicity Distribution Function Derived From the Red Giant Branch  

E-Print Network [OSTI]

We have tested the reliability of the red giant branch (RGB) as a metallicity indicator accounting for observational errors as well as the complexity of star formation histories (SFHs) and chemical evolution histories observed in various stellar systems. We generate model color-magnitude diagrams (CMDs) produced with a variety of evolutionary histories and compare the resultant metallicity estimates from the colors and magnitudes of RGB stars to the true input metallicities. We include realistic models for photometric errors and completeness in our synthetic CMDs. As expected, for simple simple stellar populations dominated by old stars, the RGB provides a very accurate estimate of the modular metallicity value for a population. An error in the age of a system targeted for this type of study may produce metallicity errors of a few tenths of a dex. The size of this metallicity error depends linearly on the age error, and we find this dependence to be stronger with more precise photometry. If the population has...

Ordoez, Antonio J

2015-01-01T23:59:59.000Z

133

The Baltimore and Utrecht models for cluster dissolution  

E-Print Network [OSTI]

The analysis of the age distributions of star cluster samples of different galaxies has resulted in two very different empirical models for the dissolution of star clusters: the Baltimore model and the Utrecht model. I describe these two models and their differences. The Baltimore model implies that the dissolution of star clusters is mass independent and that about 90% of the clusters are destroyed each age dex, up to an age of about a Gyr, after which point mass-dependent dissolution from two-body relaxation becomes the dominant mechanism. In the Utrecht model, cluster dissolution occurs in three stages: (i) mass-independent infant mortality due to the expulsion of gas up to about 10 Myr; (ii) a phase of slow dynamical evolution with strong evolutionary fading of the clusters lasting up to about a Gyr; and (iii) a phase dominated by mass dependent-dissolution, as predicted by dynamical models. I describe the cluster age distributions for mass-limited and magnitude-limited cluster samples for both models. I refrain from judging the correctness of these models.

Henny J. G. L. M. Lamers

2008-04-14T23:59:59.000Z

134

Operators Manual and Technical Reference for the Z-Beamlet Phase Modulation Failsafe System: Version 1.  

SciTech Connect (OSTI)

The need for pulse energies exceeding 4 kJ and pulse lengths [?] 2 ns in Sandia's Z-Beamlet laser (ZBL) requires that the single-frequency spectrum of its fiber-laser master oscillator be converted to a phase modulated spectrum with a modulation in dex [?] 5. Because accidental injection of single-frequency light into ZBL could result i n damage to optical materials from transverse stimulated Brillouin scattering, the presence of phase modulated (PM) light must be monitored by a reliable failsafe system that can stop a las er shot within of a few 10's of ns following a failure of the PM system. This requirement is met by combining optical heterodyne detection with high-speed electronics to indicate the pres ence or absence of phase modulated light. The transition time for the failsafe signal resultin g from a sudden failure using this technique is approximately 35 ns. This is sufficiently short to safely stop a single-frequency laser pulse from leaving ZBL's regenerative amplifier with a n approximately 35 ns margin of safety. This manual and technical reference contains detai led instructions for daily use of the PM failsafe system and provides enough additional informat ion for its maintenance and repair.

Armstrong, Darrell J.

2014-09-01T23:59:59.000Z

135

Revisiting the relationship between 6 {\\mu}m and 2-10 keV continuum luminosities of AGN  

E-Print Network [OSTI]

We have determined the relation between the AGN luminosities at rest-frame 6 {\\mu}m associated to the dusty torus emission and at 2-10 keV energies using a complete, X-ray flux limited sample of 232 AGN drawn from the Bright Ultra-hard XMM-Newton Survey. The objects have X-ray luminosities corrected for intrinsic absorption between 10^42 and 10^46 erg/s and redshifts from 0.05 to 2.8. The rest-frame 6 {\\mu}m luminosities were computed using data from the Wide-Field Infrared Survey Explorer and are based on a spectral energy distribution decomposition into AGN and galaxy emission. The best-fit relationship for the full sample is consistent with being linear, L_6 {\\mu}m $\\propto$ L_2-10 keV^0.99$\\pm$0.032, but has significant intrinsic scatter, ~0.35 dex in log L_6 {\\mu}m. Assuming a constant X-ray bolometric correction, the fraction of AGN bolometric luminosity reprocessed in the mid-IR decreases weakly, if at all, with the AGN luminosity, a finding at odds with simple receding torus models. Type 2 AGN have re...

Mateos, S; Alonso-Herrero, A; Rovilos, E; Hernn-Caballero, A; Barcons, X; Blain, A; Caccianiga, A; Della Ceca, R; Severgnini, P

2015-01-01T23:59:59.000Z

136

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

137

A MODEL ATMOSPHERE ANALYSIS OF ALPHA AURIGAE A  

SciTech Connect (OSTI)

This work presents the first quantitative composite model atmosphere analysis of Capella, the brightest near-equal-mass spectroscopic binary and principal star of the constellation Auriga. Its high-resolution spectrum leads to a slightly metal-rich object at [Fe/H] = +0.05 {+-} 0.08 dex. In line with its young age and its kinematics, this consistently associates Capella with the Hyades moving group. The measured projected rotational velocities, vsin i{sub Aa} = 3.5 {+-} 0.8 km s{sup -1} and vsin i{sub Ab} = 35.4 {+-} 3.2 km s{sup -1}, both agree with rotational and orbital coplanarity and synchronous orbital rotation for the Aa component. At an orbital period P = 104 d the primary's bound rotation together with the almost zero orbital eccentricity are both key characteristics of this binary and clearly imply that the Aa component must have passed the tip of the giant branch. Whether in that phase Capella also became a mass transfer system remains inconclusive at present, though the high rotational velocity of the less evolved Hertzsprung gap secondary and the very diverse lithium abundances of both its components render this a plausible case.

Fuhrmann, Klaus [Astronomisches Institut, Ruhr-Universitaet Bochum, Universitaetsstrasse 150, D-44780 Bochum (Germany)

2011-11-20T23:59:59.000Z

138

Deep Photometry of the Globular Cluster M5: Distance Estimates from White Dwarf and Main Sequence Stars  

E-Print Network [OSTI]

We present deep VI photometry of stars in the globular cluster M5 (NGC 5904) based on images taken with the Hubble Space Telescope. The resulting color-magnitude diagram reaches below V ~ 27 mag, revealing the upper 2-3 magnitudes of the white dwarf cooling sequence, and main sequence stars eight magnitudes and more below the turn-off. We fit the main sequence to subdwarfs of known parallax to obtain a true distance modulus of (m-M)_0 = 14.45 +/- 0.11 mag. A second distance estimate based on fitting the cluster white dwarf sequence to field white dwarfs with known parallax yielded (m-M)_0 = 14.67 +/- 0.18 mag. We couple our distance estimates with extensive photometry of the cluster's RR Lyrae variables to provide a calibration of the RR Lyrae absolute magnitude yielding M_V(RR) = 0.42 +/- 0.10 mag at [Fe/H] = -1.11 dex. We provide another luminosity calibration in the form of reddening-free Wasenheit functions. Comparison of our calibrations with predictions based on recent models combining stellar evolution and pulsation theories shows encouraging agreement. (Abridged)

Andrew C. Layden; Ata Sarajedini; Ted von Hippel; Adrienne M. Cool

2005-07-14T23:59:59.000Z

139

Neutral chlorine and molecular hydrogen at high redshift  

E-Print Network [OSTI]

Chlorine and molecular hydrogen are known to be tightly linked together in the cold phase of the local interstellar medium through rapid chemical reactions. We present here the first systematic study of this relation at high redshifts using H$_2$-bearing damped Ly$\\alpha$ systems (DLAs) detected along quasar lines of sight. Using high-resolution spectroscopic data from VLT/UVES and Keck/HIRES, we report the detection of Cl$\\,$I in 9 DLAs (including 5 new detections) out of 18 high-$z$ DLAs with $N($H$_2) \\ge 10^{17.3}\\,$cm$^{-2}$ (including a new H$_2$ detection at $z=3.09145$ towards J$\\,$2100$-$0641) and present upper limits for the remaining 9 systems. We find a $\\sim$5$\\,\\sigma$ correlation between $N$(Cl$\\,$I) and $N$(H$_2$) with only $\\sim$0.2$\\,$dex dispersion over the range 18.1$\\,<\\,$log$\\,N$(H$_2$)$\\,<\\,$20.1, thus probing column densities 10 times lower those seen towards nearby stars, roughly following the relation $N$(Cl$\\,$I$) \\approx 1.5\\times10^{-6} \\times N($H$_2)$. This relation betwee...

Balashev, S A; Klimenko, V V; Petitjean, P; Srianand, R; Ledoux, C; Ivanchik, A V; Varshalovich, D A

2015-01-01T23:59:59.000Z

140

The GAPS Programme with HARPS-N@TNG V. A comprehensive analysis of the XO-2 stellar and planetary systems  

E-Print Network [OSTI]

XO-2 is the first confirmed wide stellar binary system where the almost twin components XO-2N and XO-2S have planets. This stimulated a detailed characterization study of the stellar and planetary components based on new observations. We collected high-resolution spectra with the HARPS-N spectrograph and multi-band light curves. Spectral analysis led to an accurate determination of the stellar atmospheric parameters and characterization of the stellar activity. We collected 14 transit light curves of XO-2Nb used to improve the transit parameters. Photometry provided accurate magnitude differences between the stars and a measure of their rotation periods. The iron abundance of XO-2N was found to be +0.054 dex greater, within more than 3-sigma, than that of XO-2S. We confirm a long-term variation in the radial velocities of XO-2N, and we detected a turn-over with respect to previous measurements. We suggest the presence of a second massive companion in an outer orbit or the stellar activity cycle as possible ca...

Damasso, M; Bonomo, A S; Desidera, S; Lanza, A F; Nascimbeni, V; Esposito, M; Scandariato, G; Sozzetti, A; Cosentino, R; Gratton, R; Malavolta, L; Rainer, M; Gandolfi, D; Poretti, E; Sanchez, R Zanmar; Ribas, I; Santos, N; Affer, L; Andreuzzi, G; Barbieri, M; Bedin, L R; Benatti, S; Bernagozzi, A; Bertolini, E; Bonavita, M; Borsa, F; Borsato, L; Boschin, W; Calcidese, P; Carbognani, A; Cenadelli, D; Christille, J M; Claudi, R U; Covino, E; Cunial, A; Giacobbe, P; Granata, V; Harutyunyan, A; Lattanzi, M G; Leto, G; Libralato, M; Lodato, G; Lorenzi, V; Mancini, L; Fiorenzano, A F Martinez; Marzari, F; Masiero, S; Micela, G; Molinari, E; Molinaro, M; Munari, U; Murabito, S; Pagano, I; Pedani, M; Piotto, G; Rosenberg, A; Silvotti, R; Southworth, J

2015-01-01T23:59:59.000Z

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141

CALIBRATING C-IV-BASED BLACK HOLE MASS ESTIMATORS  

SciTech Connect (OSTI)

We present the single-epoch black hole mass estimators based on the C IV {lambda}1549 broad emission line, using the updated sample of the reverberation-mapped active galactic nuclei and high-quality UV spectra. By performing multi-component spectral fitting analysis, we measure the C IV line widths (FWHM{sub C{sub IV}} and line dispersion, {sigma}{sub C{sub IV}}) and the continuum luminosity at 1350 A (L{sub 1350}) to calibrate the C-IV-based mass estimators. By comparing with the H{beta} reverberation-based masses, we provide new mass estimators with the best-fit relationships, i.e., M{sub BH}{proportional_to}L{sub 1350}{sup 0.50{+-}0.07}{sigma}{sub C{sub IV}{sup 2}} and M{sub BH}{proportional_to}L{sub 1350}{sup 0.52{+-}0.09} FWHM{sub C{sub IV}{sup 0.56{+-}0.48}}. The new C-IV-based mass estimators show significant mass-dependent systematic difference compared to the estimators commonly used in the literature. Using the published Sloan Digital Sky Survey QSO catalog, we show that the black hole mass of high-redshift QSOs decreases on average by {approx}0.25 dex if our recipe is adopted.

Park, Daeseong; Woo, Jong-Hak; Shin, Jaejin [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Denney, Kelly D., E-mail: pds2001@astro.snu.ac.kr, E-mail: woo@astro.snu.ac.kr, E-mail: jjshin@astro.snu.ac.kr, E-mail: kelly@dark-cosmology.dk [Dark Cosmology Centre, Niels Bohr Institute, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark)

2013-06-20T23:59:59.000Z

142

Planetary Companions Around Two Solar Type Stars: HD 195019 and HD 217107  

E-Print Network [OSTI]

We have enlarged the sample of stars in the planet search at Lick Observatory. Doppler measurements of 82 new stars observed at Lick Observatory, with additional velocities from Keck Observatory, have revealed two new planet candidates. The G3V/IV star, HD 195019, exhibits Keplerian velocity variations with a period of 18.27 d, an orbital eccentricity of 0.03 +/- 0.03, and M sin i = 3.51 M_Jup. Based on a measurement of Ca II H&K emission, this star is chromospherically inactive. We estimate the metallicity of HD 195019 to be approximately solar from ubvy photometry. The second planet candidate was detected around HD 217107, a G7V star. This star exhibits a 7.12 d Keplerian period with eccentricity 0.14 +/- 0.05 and M sin i = 1.27 M_Jup. HD 217107 is also chromospherically inactive. The photometric metallicity is found to be [Fe/H] = +0.29 +/- 0.1 dex. Given the relatively short orbital period, the absence of tidal spin-up of HD 217107 provides a theoretical constraint on the upper limit of the companion mass of < 11 M_Jup.

D. A. Fischer; G. W. Marcy; R. P. Butler; S. S. Vogt; K. Apps

1998-10-26T23:59:59.000Z

143

Growth of Spirals: Secular or Driven by Mergers ?  

E-Print Network [OSTI]

The physical phenomena contributing to the galaxy growth can be tested all the way to z= 1. Galaxy mass, extinction, star formation and gas metal abundance can be measured in a robust way, as well as the distribution of the galaxy morphologies. I discuss here the observational methods and their accuracy. Physical quantities can be evaluated with uncertainties much lower than 0.3 dex, if they are based on 2 sets of independent measurements. For example, at a given IMF, the star formation rate is well estimated by combining flux measurements of the extinction corrected Balmer line and of the mid-IR continuum. Spiral mass growth had occurred from gas accretion and from merging. Gas accretion can explain at most half of the spiral mass growth: at moderate redshift, the numerous population of compact, merger and irregular galaxies requires another origin. A spiral rebuilding scenario is able to reproduce all the evolutionary trends observed since z~1, and could be at the origin of the present-day, numerous population of early type spirals.

F. Hammer

2005-09-30T23:59:59.000Z

144

Inverting Color-Magnitude Diagrams to Access Precise Star Cluster Parameters: A Bayesian Approach  

E-Print Network [OSTI]

We demonstrate a new Bayesian technique to invert color-magnitude diagrams of main sequence and white dwarf stars to reveal the underlying cluster properties of age, distance, metallicity, and line-of-sight absorption, as well as individual stellar masses. The advantages our technique has over traditional analyses of color-magnitude diagrams are objectivity, precision, and explicit dependence on prior knowledge of cluster parameters. Within the confines of a given set of often-used models of stellar evolution, the initial-final mass relation, and white dwarf cooling, and assuming photometric errors that one could reasonably achieve with the Hubble Space Telescope, our technique yields exceptional precision for even modest numbers of cluster stars. For clusters with 50 to 400 members and one to a few dozen white dwarfs, we find typical internal errors of sigma([Fe/H]) <= 0.03 dex, sigma(m-M) <= 0.02 mag, and sigma(Av) <= 0.01 mag. We derive cluster white dwarf ages with internal errors of typically only 10% for clusters with only three white dwarfs and almost always <= 5% with ten white dwarfs. These exceptional precisions will allow us to test white dwarf cooling models and standard stellar evolution models through observations of white dwarfs in open and globular clusters.

Ted von Hippel; William H. Jefferys; James Scott; Nathan Stein; D. E. Winget; Steven DeGennaro; Albert Dam; Elizabeth Jeffery

2006-03-17T23:59:59.000Z

145

We determined basic stellar parameters and the chemical abundances of a small sample of 15 hot, H-rich post-AGB stars using high-resolution, high-  

E-Print Network [OSTI]

stages of post-AGB stellar evolution. Spectral analysis The photospheric model spectral energy of Science Institute for Astronomy and Astrophysics Acknowledgements TR is supported by the German Aerospace] denotes log [mass fraction / solar mass fraction]. The typical error is 0.3 dex. Table 1: Parameters

Barnstedt, Jürgen

146

MEASURING GALAXY STAR FORMATION RATES FROM INTEGRATED PHOTOMETRY: INSIGHTS FROM COLOR-MAGNITUDE DIAGRAMS OF RESOLVED STARS  

SciTech Connect (OSTI)

We use empirical star formation histories (SFHs), measured from Hubble-Space-Telescope-based resolved star color-magnitude diagrams, as input into population synthesis codes to model the broadband spectral energy distributions (SEDs) of 50 nearby dwarf galaxies (6.5 < log M{sub *}/M{sub Sun} < 8.5, with metallicities {approx}10% solar). In the presence of realistic SFHs, we compare the modeled and observed SEDs from the ultraviolet (UV) through near-infrared and assess the reliability of widely used UV-based star formation rate (SFR) indicators. In the FUV through i bands, we find that the observed and modeled SEDs are in excellent agreement. In the Spitzer 3.6 {mu}m and 4.5 {mu}m bands, we find that modeled SEDs systematically overpredict observed luminosities by up to {approx}0.2 dex, depending on treatment of the TP-AGB stars in the synthesis models. We assess the reliability of UV luminosity as a SFR indicator, in light of independently constrained SFHs. We find that fluctuations in the SFHs alone can cause factor of {approx}2 variations in the UV luminosities relative to the assumption of a constant SFH over the past 100 Myr. These variations are not strongly correlated with UV-optical colors, implying that correcting UV-based SFRs for the effects of realistic SFHs is difficult using only the broadband SED. Additionally, for this diverse sample of galaxies, we find that stars older than 100 Myr can contribute from <5%-100% of the present day UV luminosity, highlighting the challenges in defining a characteristic star formation timescale associated with UV emission. We do find a relationship between UV emission timescale and broadband UV-optical color, though it is different than predictions based on exponentially declining SFH models. Our findings have significant implications for the comparison of UV-based SFRs across low-metallicity populations with diverse SFHs.

Johnson, Benjamin D. [Institute d'Astrophysique de Paris, CNRS, UPMC, 98bis Bd Arago, F-75014 Paris (France); Weisz, Daniel R.; Dalcanton, Julianne J.; Johnson, L. C.; Williams, Benjamin F. [Department of Astronomy, Box 351580, University of Washington, Seattle, WA 98195 (United States); Dale, Daniel A. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Dolphin, Andrew E. [Raytheon, 1151 E. Hermans Road, Tucson, AZ 85756 (United States); Gil de Paz, Armando [CEI Campus Moncloa, UCM-UPM, Departamento de Astrofisica y CC. de la Atmosfera, Facultad de CC. Fisicas, Universidad Complutense de Madrid, Avda. Complutense s/n, E-28040 Madrid (Spain); Kennicutt, Robert C. Jr. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Lee, Janice C. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Skillman, Evan D. [Department of Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States); Boquien, Mederic [Marseille Universite, CNRS, LAM (Laboratoire d'Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France)

2013-07-20T23:59:59.000Z

147

The solar photospheric abundance of hafnium and thorium. Results from CO5BOLD 3D hydrodynamic model atmospheres  

E-Print Network [OSTI]

Context: The stable element hafnium (Hf) and the radioactive element thorium (Th) were recently suggested as a suitable pair for radioactive dating of stars. The applicability of this elemental pair needs to be established for stellar spectroscopy. Aims: We aim at a spectroscopic determination of the abundance of Hf and Th in the solar photosphere based on a \\cobold 3D hydrodynamical model atmosphere. We put this into a wider context by investigating 3D abundance corrections for a set of G- and F-type dwarfs. Method: High-resolution, high signal-to-noise solar spectra were compared to line synthesis calculations performed on a solar CO5BOLD model. For the other atmospheres, we compared synthetic spectra of CO5BOLD 3D and associated 1D models. Results: For Hf we find a photospheric abundance A(Hf)=0.87+-0.04, in good agreement with a previous analysis, based on 1D model atmospheres. The weak Th ii 401.9 nm line constitutes the only Th abundance indicator available in the solar spectrum. It lies in the red wing of an Ni-Fe blend exhibiting a non-negligible convective asymmetry. Accounting for the asymmetry-related additional absorption, we obtain A(Th)=0.09+-0.03, consistent with the meteoritic abundance, and about 0.1 dex lower than obtained in previous photospheric abundance determinations. Conclusions: Only for the second time, to our knowledge, has am non-negligible effect of convective line asymmetries on an abundance derivation been highlighted. Three-dimensional hydrodynamical simulations should be employed to measure Th abundances in dwarfs if similar blending is present, as in the solar case. In contrast, 3D effects on Hf abundances are small in G- to mid F-type dwarfs and sub-giants, and 1D model atmospheres can be conveniently used.

Elisabetta Caffau; L. Sbordone; H. -G. Ludwig; P. Bonifacio; M. Steffen; N. T. Behara

2008-03-25T23:59:59.000Z

148

Spectroscopic metallicities for Fornax UCDs, GCs and dE,Ns  

E-Print Network [OSTI]

Various formation channels for the puzzling ultra-compact dwarf galaxies (UCDs) have been proposed in the last few years. To better judge on some of the competing scenarios, we present spectroscopic [Fe/H] estimates for a sample of 26 compact objects in the central region of the Fornax cluster, covering the magnitude range of UCDs and bright globular clusters. We find a break in the metallicity distribution of compact objects at M_V ~ -11 mag (~3*10^6 M_sun): for M_V-11 mag. This metallicity break is accompanied by a change in the size-luminosity relation for compact objects, as deduced from HST-imaging: for M_V-11 mag, r_h is almost luminosity-independent. We therefore assume a limiting absolute magnitude of M_V=-11 mag between UCDs and globular clusters. The mean metallicity of five Fornax dE,N nuclei included in our study is about 0.8 dex lower than that of the UCDs, at 4.5 sigma significance. Because of this large metallicity discrepancy we disfavor the hypothesis that most of the Fornax UCDs are the remnant nuclei of tidally stripped dE,Ns. Our metallicity estimates for UCDs are closer to but slightly below those derived for young massive clusters (YMCs) of comparable masses. We therefore favor a scenario where most UCDs in Fornax are successors of merged YMCs produced in the course of violent galaxy-galaxy mergers. It is noted that in contrast to that, the properties of Virgo UCDs are more consistent with the stripping scenario, suggesting that different UCD formation channels may dominate in either cluster.

S. Mieske; M. Hilker; L. Infante; A. Jordan

2005-12-20T23:59:59.000Z

149

A NEW DISTANCE TO M33 USING BLUE SUPERGIANTS AND THE FGLR METHOD  

SciTech Connect (OSTI)

The quantitative spectral analysis of medium resolution optical spectra of A and B supergiants obtained with DEIMOS and ESI at the Keck Telescopes is used to determine a distance modulus of 24.93 +- 0.11 mag (968 +- 50 kpc) for the Triangulum Galaxy M33. The analysis yields stellar effective temperatures, gravities, interstellar reddening, and extinction, the combination of which provides a distance estimate via the flux-weighted gravity-luminosity relationship (FGLR). This result is based on an FGLR calibration that is continually being polished. An average reddening of (E(B - V)) approx 0.08 mag is found, with a large variation ranging from 0.01 to 0.16 mag, however, demonstrating the importance of accurate individual reddening measurements for stellar distance indicators in galaxies with evident signatures of interstellar absorption. The large-distance modulus found is in good agreement with recent work on eclipsing binaries, planetary nebulae, long-period variables, RR Lyrae stars, and also with Hubble Space Telescope (HST) observations of Cepheids, if reasonable reddening assumptions are made for the Cepheids. Since distances based on the tip of the red giant branch (TRGB) method found in the literature give conflicting results, we have used HST Advanced Camera for Surveys V- and I-band images of outer regions of M33 to determine a TRGB distance of 24.84 +- 0.10 mag, in basic agreement with the FGLR result. We have also determined stellar metallicities and discussed the metallicity gradient in the disk of M33. We find metallicity of Z {sub sun} at the center and 0.3 Z {sub sun} in the outskirts at a distance of one isophotal radius. The average logarithmic metallicity gradient is -0.07 +- 0.01 dex kpc{sup -1}. However, there is a large scatter around this average value, very similar to what has been found for the H II regions in M33.

U, Vivian; Urbaneja, Miguel A.; Kudritzki, Rolf-Peter; Jacobs, Bradley A.; Bresolin, Fabio [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Przybilla, Norbert, E-mail: vivian@ifa.hawaii.ed, E-mail: urbaneja@ifa.hawaii.ed, E-mail: kud@ifa.hawaii.ed, E-mail: bjacobs@ifa.hawaii.ed, E-mail: bresolin@ifa.hawaii.ed, E-mail: przybilla@sternwarte.uni-erlangen.d [Dr. Remeis-Sternwarte Bamberg, Sternwartstrasse 7, D-96049 Bamberg (Germany)

2009-10-20T23:59:59.000Z

150

THE ASSEMBLY HISTORY OF DISK GALAXIES. I. THE TULLY-FISHER RELATION TO z {approx_equal} 1.3 FROM DEEP EXPOSURES WITH DEIMOS  

SciTech Connect (OSTI)

We present new measures of the evolving scaling relations between stellar mass, luminosity and rotational velocity for a morphologically inclusive sample of 129 disk-like galaxies with z{sub AB} < 22.5 in the redshift range 0.2 in determining characteristic rotational velocities for each galaxy. Rotation curves are reliably traced to the radius where they begin to flatten for {approx}90% of our sample, and we model the HST-resolved bulge and disk components in order to accurately de-project our measured velocities, accounting for seeing and dispersion. We demonstrate the merit of these advances by recovering an intrinsic scatter on the stellar mass Tully-Fisher relation a factor of two to three less than in previous studies at intermediate redshift and comparable to that of locally determined relations. With our increased precision, we find that the relation is well established by (z) {approx} 1, with no significant evolution to (z) {approx} 0.3, {Delta}M{sub *} {approx} 0.04 {+-} 0.07 dex. A clearer trend of evolution is seen in the B-band Tully-Fisher relation corresponding to a decline in luminosity of {Delta}M{sub B} {approx} 0.85 {+-} 0.28 magnitudes at fixed velocity over the same redshift range, reflecting the changes in star formation over this period. As an illustration of the opportunities possible when gas masses are available for a sample such as ours, we show how our dynamical and stellar mass data can be used to evaluate the likely contributions of baryons and dark matter to the assembly history of spiral galaxies.

Miller, Sarah H.; Sullivan, Mark [Oxford Astrophysics, Oxford, OX1 3RH (United Kingdom); Bundy, Kevin [Astronomy Department, University of California, Berkeley, CA 94720 (United States); Ellis, Richard S. [California Institute of Technology, Pasadena, CA 91125 (United States); Treu, Tommaso, E-mail: s.miller1@physics.ox.ac.uk [UC Santa Barbara Physics, Santa Barbara, CA 93106 (United States)

2011-11-10T23:59:59.000Z

151

CALIBRATING THE STAR FORMATION RATE AT z {approx} 1 FROM OPTICAL DATA  

SciTech Connect (OSTI)

We present a star formation rate (SFR) calibration based on optical data that is consistent with average observed rates in both the red and blue galaxy populations at z {approx} 1. The motivation for this study is to calculate SFRs for DEEP2 Redshift Survey galaxies in the 0.7 < z < 1.4 redshift range, but our results are generally applicable to similar optically selected galaxy samples without requiring UV or IR data. Using SFR fits from UV/optical spectral energy distributions (SEDs) in the All-Wavelength Extended Groth Strip International Survey, we explore the behavior of rest-frame B-band magnitude, observed [O II] luminosity, and rest-frame color with SED-fit SFR for both red sequence and blue cloud galaxies. The resulting SFR calibration is based on three optical-band observables: M{sub B} , (U - B), and (B - V). The best-fit linear relation produces residual errors of 0.3 dex rms scatter for the full color-independent sample with minimal correlated residual error in L[O II] or stellar mass. We then compare the calibrated z {approx} 1 SFRs to two diagnostics that use L[O II] as a tracer in local galaxies and correct for dust extinction at intermediate redshifts through either galaxy B-band luminosity or stellar mass. We find that an L[O II]-M{sub B} SFR calibration commonly used in the literature agrees well with our calculated SFRs after correcting for the average B-band luminosity evolution in L{sub *} galaxies. However, we find better agreement with a local L[O II]-based SFR calibration that includes stellar mass to correct for reddening effects, indicating that stellar mass is a better tracer of dust extinction for all galaxy types and less affected by systematic evolution than galaxy luminosity from z = 1 to the current epoch.

Mostek, Nick [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Coil, Alison L.; Moustakas, John [Center for Astrophysics and Space Sciences, University of California, San Diego, La Jolla, CA 92093 (United States); Salim, Samir [Department of Astronomy, Indiana University, Bloomington, IN 47405 (United States); Weiner, Benjamin J., E-mail: njmostek@lbl.gov [Steward Observatory, Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States)

2012-02-20T23:59:59.000Z

152

Discovery of a peculiar Cepheid-like star towards the northern edge of the Small Magellanic Cloud  

E-Print Network [OSTI]

For seven years, the EROS-2 project obtained a mass of photometric data on variable stars. We present a peculiar Cepheid-like star, in the direction of the Small Magellanic Cloud, which demonstrates unusual photometric behaviour over a short time interval. We report on data of the photometry acquired by the MARLY telescope and spectroscopy from the EFOSC instrument for this star, called EROS2 J005135-714459(sm0060n13842), which resembles the unusual Cepheid HR 7308. The light curve of our target is analysed using the Analysis of Variance method to determine a pulsational period of 5.5675 days. A fit of time-dependent Fourier coefficients is performed and a search for proper motion is conducted. The light curve exhibits a previously unobserved and spectacular change in both mean magnitude and amplitude, which has no clear theoretical explanation. Our analysis of the spectrum implies a radial velocity of 104 km s$^{-1}$ and a metallicity of -0.4$\\pm$0.2 dex. In the direction of right ascension, we measure a proper motion of 17.4$\\pm$6.0 mas yr$^{-1}$ using EROS astrometry, which is compatible with data from the NOMAD catalogue. The nature of EROS2 J005135-714459(sm0060n13842) remains unclear. For this star, we may have detected a non-zero proper motion for this star, which would imply that it is a foreground object. Its radial velocity, pulsational characteristics, and photometric data, however, suggest that it is instead a Cepheid-like object located in the SMC. In such a case, it would present a challenge to conventional Cepheid models.

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

2008-05-29T23:59:59.000Z

153

THE SLACS SURVEY. VIII. THE RELATION BETWEEN ENVIRONMENT AND INTERNAL STRUCTURE OF EARLY-TYPE GALAXIES  

SciTech Connect (OSTI)

We study the relation between the internal structure of early-type galaxies and their environment using 70 strong gravitational lenses from the SLACS Survey. The Sloan Digital Sky Survey (SDSS) database is used to determine two measures of overdensity of galaxies around each lens-the projected number density of galaxies inside the tenth nearest neighbor ({sigma}{sub 10}) and within a cone of radius one h{sup -1} Mpc (D {sub 1}). Our main results are as follows. (1) The average overdensity is somewhat larger than unity, consistent with lenses preferring overdense environments as expected for massive early-type galaxies (12/70 lenses are in known groups/clusters). (2) The distribution of overdensities is indistinguishable from that of 'twin' nonlens galaxies selected from SDSS to have the same redshift and stellar velocity dispersion {sigma}{sub *}. Thus, within our errors, lens galaxies are an unbiased population, and the SLACS results can be generalized to the overall population of early-type galaxies. (3) Typical contributions from external mass distribution are no more than a few percent in local mass density, reaching 10-20% ({approx}0.05-0.10 external convergence) only in the most extreme overdensities. (4) No significant correlation between overdensity and slope of the mass-density profile of the lens galaxies is found. (5) Satellite galaxies (those with a more luminous companion) have marginally steeper mass-density profiles (as quantified by f {sub SIE} = {sigma}{sub *}/{sigma}{sub SIE} = 1.12 {+-} 0.05 versus 1.01 {+-} 0.01) and smaller dynamically normalized mass enclosed within the Einstein radius ({delta}log M {sub Ein}/M {sub dim} differs by -0.09 {+-} 0.03 dex) than central galaxies (those without). This result suggests that tidal stripping may affect the mass structure of early-type galaxies down to kpc scales probed by strong lensing, when they fall into larger structures.

Treu, Tommaso; Gavazzi, Raphael; Gorecki, Alexia; Marshall, Philip J. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Koopmans, Leon V. E. [Kapteyn Institute, P.O. Box 800, 9700AV Groningen (Netherlands); Bolton, Adam S. [Institute for Astronomy, University of Hawai'i, 2680 Woodlawn Dr., Honolulu, HI 96822 (United States); Moustakas, Leonidas A. [Jet Propulsion Laboratory, 4800 Oak Grove Dr, Caltech, MS169-327, Pasadena, CA 91109 (United States); Burles, Scott [Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 (United States)], E-mail: tt@physics.ucsb.edu, E-mail: pjm@physics.ucsb.edu, E-mail: gavazzi@iap.fr, E-mail: koopmans@astro.rug.nl, E-mail: bolton@ifa.hawaii.edu, E-mail: leonidas@jpl.nasa.gov, E-mail: burles@mit.edu

2009-01-01T23:59:59.000Z

154

DIAGNOSING THE TIME DEPENDENCE OF ACTIVE REGION CORE HEATING FROM THE EMISSION MEASURE. II. NANOFLARE TRAINS  

SciTech Connect (OSTI)

The time dependence of heating in solar active regions can be studied by analyzing the slope of the emission measure distribution coolward of the peak. In a previous study we showed that low-frequency heating can account for 0% to 77% of active region core emission measures. We now turn our attention to heating by a finite succession of impulsive events for which the timescale between events on a single magnetic strand is shorter than the cooling timescale. We refer to this scenario as a 'nanoflare train' and explore a parameter space of heating and coronal loop properties with a hydrodynamic model. Our conclusions are (1) nanoflare trains are consistent with 86% to 100% of observed active region cores when uncertainties in the atomic data are properly accounted for; (2) steeper slopes are found for larger values of the ratio of the train duration {Delta} {sub H} to the post-train cooling and draining timescale {Delta} {sub C}, where {Delta} {sub H} depends on the number of heating events, the event duration and the time interval between successive events ({tau} {sub C}); (3) {tau} {sub C} may be diagnosed from the width of the hot component of the emission measure provided that the temperature bins are much smaller than 0.1 dex; (4) the slope of the emission measure alone is not sufficient to provide information about any timescale associated with heating-the length and density of the heated structure must be measured for {Delta} {sub H} to be uniquely extracted from the ratio {Delta} {sub H}/{Delta} {sub C}.

Reep, J. W.; Bradshaw, S. J. [Department of Physics and Astronomy, Rice University, Houston, TX 77005 (United States)] [Department of Physics and Astronomy, Rice University, Houston, TX 77005 (United States); Klimchuk, J. A., E-mail: jeffrey.reep@rice.edu, E-mail: stephen.bradshaw@rice.edu, E-mail: james.a.klimchuk@nasa.gov [NASA Goddard Space Flight Center, Solar Physics Lab., Code 671, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States)

2013-02-20T23:59:59.000Z

155

THE COMPLEX PHYSICS OF DUSTY STAR-FORMING GALAXIES AT HIGH REDSHIFTS AS REVEALED BY HERSCHEL AND SPITZER  

SciTech Connect (OSTI)

We combine far-infrared photometry from Herschel (PEP/HerMES) with deep mid-infrared spectroscopy from Spitzer to investigate the nature and the mass assembly history of a sample of 31 luminous and ultraluminous infrared galaxies ((U)LIRGs) at z {approx} 1 and 2 selected in GOODS-S with 24 {mu}m fluxes between 0.2 and 0.5 mJy. We model the data with a self-consistent physical model (GRASIL) which includes a state-of-the-art treatment of dust extinction and reprocessing. We find that all of our galaxies appear to require massive populations of old (>1 Gyr) stars and, at the same time, to host a moderate ongoing activity of star formation (SFR {<=} 100 M {sub Sun} yr{sup -1}). The bulk of the stars appear to have been formed a few Gyr before the observation in essentially all cases. Only five galaxies of the sample require a recent starburst superimposed on a quiescent star formation history. We also find discrepancies between our results and those based on optical-only spectral energy distribution (SED) fitting for the same objects; by fitting their observed SEDs with our physical model we find higher extinctions (by {Delta}A {sub V} {approx} 0.81 and 1.14) and higher stellar masses (by {Delta}log(M {sub *}) {approx} 0.16 and 0.36 dex) for z {approx} 1 and z {approx} 2 (U)LIRGs, respectively. The stellar mass difference is larger for the most dust-obscured objects. We also find lower SFRs than those computed from L {sub IR} using the Kennicutt relation due to the significant contribution to the dust heating by intermediate-age stellar populations through 'cirrus' emission ({approx}73% and {approx}66% of the total L {sub IR} for z {approx} 1 and z {approx} 2 (U)LIRGs, respectively).

Lo Faro, B.; Franceschini, A.; Vaccari, M.; Rodighiero, G.; Feltre, A.; Marchetti, L. [Dipartimento di Fisica e Astronomia, Universita di Padova, vicolo Osservatorio, 3, I-35122 Padova (Italy)] [Dipartimento di Fisica e Astronomia, Universita di Padova, vicolo Osservatorio, 3, I-35122 Padova (Italy); Silva, L. [INAF-OATs, Via Tiepolo 11, I-34131 Trieste (Italy)] [INAF-OATs, Via Tiepolo 11, I-34131 Trieste (Italy); Berta, S.; Lutz, D.; Magnelli, B. [MPE, Postfach 1312, D-85741, Garching (Germany)] [MPE, Postfach 1312, D-85741, Garching (Germany); Bock, J. [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States)] [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Burgarella, D.; Buat, V. [Laboratoire d'Astrophysique de Marseille, OAMP, Universite Aix-Marseille, CNRS, 38 rue Frederic Joliot-Curie, F-13388 Marseille Cedex 13 (France)] [Laboratoire d'Astrophysique de Marseille, OAMP, Universite Aix-Marseille, CNRS, 38 rue Frederic Joliot-Curie, F-13388 Marseille Cedex 13 (France); Cava, A. [Departamento de Astrofisica, Facultad de CC. Fisicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain)] [Departamento de Astrofisica, Facultad de CC. Fisicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom)] [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States)] [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Farrah, D.; Hurley, P. [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom)] [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom); Solares, E. A. Gonzalez [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); Magdis, G., E-mail: barbara.lofaro@studenti.unipd.it [Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); and others

2013-01-10T23:59:59.000Z

156

On the metallicity of the Milky Way thin disc and photometric abundance scales  

E-Print Network [OSTI]

The mean metallicity of the Milky Way thin disc in the solar neighbourhood is still a matter of debate, and has recently been subject to upward revision (Haywood, 2001). Our star sample was drawn from a set of solar neighbourhood dwarfs with photometric metallicities. In a recent study, Reid (2002) suggests that our metallicity calibration, based on Geneva photometry, is biased. We show here that the effect detected by Reid is not a consequence of our adopted metallicity scale, and we confirm that our findings are robust. On the contrary, the application to Stromgren photometry of the Schuster & Nissen metallicity scale is problematic. Systematic discrepancies of about 0.1 to 0.3 dex affect the photometric metallicity determination of metal rich stars, on the colour interval 0.22< b-y <0.59, i.e including F and G stars. For F stars, it is shown that this is a consequence of a mismatch between the standard sequence m_1(b-y) of the Hyades used by Schuster & Nissen to calibrate their metallicity scale, and the system of Olsen (1993, 1994ab). It means that although Schuster & Nissen calibration and Olsen photometry are intrinsically correct, there are mutually incompatible for metal rich, F-type stars. For G stars, the discrepancy is most probably the continuation of the same problem, albeit worthen by the lack of spectroscopic calibrating stars. A corrected calibration is proposed which renders the calibration of Schuster & Nissen applicable to the catalogues of Olsen. We also give a simpler calibration referenced to the Hyades sequence, valid over the same color and metallicity ranges.

M. Haywood

2002-06-28T23:59:59.000Z

157

THE FUTURE OF THE SUN: AN EVOLVED SOLAR TWIN REVEALED BY CoRoT  

SciTech Connect (OSTI)

The question of whether the Sun is peculiar within the class of solar-type stars has been the subject of active investigation over the past three decades. Although several solar twins have been found with stellar parameters similar to those of the Sun (albeit in a range of Li abundances and with somewhat different compositions), their rotation periods are unknown, except for 18 Sco, which is younger than the Sun and with a rotation period shorter than solar. It is difficult to obtain rotation periods for stars of solar age from ground-based observations, as a low-activity level implies a shallow rotational modulation of their light curves. CoRoT has provided space-based long time series from which the rotation periods of solar twins as old as the Sun could be estimated. Based on high-signal-to-noise, high-resolution spectroscopic observations gathered at the Subaru Telescope, we show that the star CoRoT ID 102684698 is a somewhat evolved solar twin with a low Li abundance. Its rotation period is 29 {+-} 5 days, compatible with its age (6.7 Gyr) and low lithium content, A{sub Li} {approx}< 0.85 dex. Interestingly, our CoRoT solar twin seems to have enhanced abundances of the refractory elements with respect to the Sun, a typical characteristic of most nearby twins. With a magnitude V {approx_equal} 14.1, ID 102684698 is the first solar twin revealed by CoRoT, the farthest field solar twin so far known, and the only solar twin older than the Sun for which a rotation period has been determined.

Do Nascimento, J.-D. Jr.; Da Costa, J. S.; Castro, M. [Departamento de Fisica Teorica e Experimental (DFTE), Universidade Federal do Rio Grande do Norte (UFRN), CP 1641, 59072-970 Natal, RN (Brazil); Takeda, Y. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Melendez, J. [Departamento de Astronomia do IAG/USP, Universidade de Sao Paulo, Rua do Matao 1226, 05508-900 Sao Paulo, SP (Brazil); Porto de Mello, G. F., E-mail: dias@dfte.ufrn.br [Observatrio do Valongo, UFRJ, Ladeira do Pedro Antonio 43, 20080-090 Rio de Janeiro, RJ (Brazil)

2013-07-10T23:59:59.000Z

158

Multicommodity formulations for the prize collecting vehicle routing  

E-Print Network [OSTI]

wells are pumped using artificial lift systems. One such system is the Mobile Oil Recovery (MOR) unit. The MOR unit is an artificial lift system which is used to exploit wells whose production is marginal, multiobjective. R´esum´e Les unit´es mobiles de pompage sont des camions munis d'un syst`eme d'ex- traction de p

Paris-Sud XI, Université de

159

MEMBROS DO CONSUNI (atualizada em 23/5/2014)  

E-Print Network [OSTI]

(DPP) 04 Mauro Luiz Rabelo Decano (DEG) 05 Thérèse Hofmann Gatti R. da Costa Decana (DEX) 06 Denise.10.16 Verônica Moreira Amado Vice-Diretor 18.12.12 a 17.12.16 19 Maria Fátima de Sousa Diretora (FS) 16-Diretora (IB) 01/03/14 a 28/03/18 22 Sadi Dal Rosso Diretor (ICS) 08.12.12 a 07.12.16 Carlos Emanuel Manzolillo

Maier, Rudolf Richard

160

Comisso Prpria de Avaliao Relatrio deAutoavaliao Institucional  

E-Print Network [OSTI]

Finanças (DAF) Profa. Gardênia da Silva Abbad Decana de Gestão de Pessoas (DGP) Prof. Mauro Luiz Rabelo Extensão (DEX) Prof. Carlos Alberto Müller Lima Torres Decano de Planejamento e Orçamento (DPO) #12 Geraldo de Sousa Junior (Reitor ­ Presidente) Prof. José Américo Soares Garcia (Decano de Ensino de

Maier, Rudolf Richard

Note: This page contains sample records for the topic "antiknock in dex" from the National Library of EnergyBeta (NLEBeta).
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161

Uncovering Additional Clues to Galaxy Evolution. II. The Environmental Impact of the Virgo Cluster on the Evolution of Dwarf Irregular Galaxies  

E-Print Network [OSTI]

The impact of the cluster environment on the evolution of dwarf galaxies is investigated by comparing the properties of a sample of dwarf irregulars (dIs) in the Virgo Cluster with a control sample of nearby ("field") dIs having oxygen abundances derived from [O III]4363 measurements and measured distances from resolved stellar constituents. Spectroscopic data are obtained for H II regions in 11 Virgo dIs distributed in the central and outer regions of the cluster. To ensure that oxygen abundances are derived in a homogeneous manner, oxygen abundances for field and Virgo dIs are computed using the bright-line method and compared with abundances directly obtained from [O III]4363, where available. They are found to agree to within about 0.2 dex with no systematic offset. At a given optical luminosity, there is no systematic difference in oxygen abundance between the sample of Virgo dIs and the sample of nearby dIs. However, five of the eleven Virgo dIs exhibit much lower baryonic gas fractions than field dIs at comparable oxygen abundances. Using field dIs as a reference, a gas-deficiency index for dIs is constructed, making it possible quantitatively to identify which galaxies have lost gas. For the Virgo sample, some of the dwarfs are gas-deficient by a factor of 30. The gas-deficiency correlates roughly with the X-ray surface brightness of the intracluster gas. Ram-pressure stripping can best explain the observed gas-poor dIs in the cluster sample. Together with the lack of significant fading and reddening of the gas-poor dIs compared to gas-normal dIs, these observations suggest that the gas-poor dIs in Virgo have recently encountered the intracluster medium for the first time. Faded remnants of gas-poor dIs in Virgo will resemble bright dwarf ellipticals presently seen in the cluster core.

Henry Lee; Marshall L. McCall; Michael G. Richer

2003-03-17T23:59:59.000Z

162

PROBING THE LOW-REDSHIFT STAR FORMATION RATE AS A FUNCTION OF METALLICITY THROUGH THE LOCAL ENVIRONMENTS OF TYPE II SUPERNOVAE  

SciTech Connect (OSTI)

Type II supernovae (SNe) can be used as a star formation tracer to probe the metallicity distribution of global low-redshift star formation. We present oxygen and iron abundance distributions of Type II SN progenitor regions that avoid many previous sources of bias. Because iron abundance, rather than oxygen abundance, is of key importance for the late stage evolution of the massive stars that are the progenitors of core-collapse supernovae, and because iron enrichment lags oxygen enrichment, we find a general conversion from oxygen abundance to iron abundance. The distributions we present here are the best yet observational standard of comparison for evaluating how different classes of supernovae depend on progenitor metallicity. We spectroscopically measure the gas-phase oxygen abundance near a representative subsample of the hosts of Type II SNe from the first-year Palomar Transient Factory (PTF) SN search, using a combination of Sloan Digital Sky Survey (SDSS) spectra near the SN location (9 hosts) and new longslit spectroscopy (25 hosts). The median metallicity of these 34 hosts at or near the SN location is 12+log(O/H) = 8.65, with a median error of 0.09. The median host galaxy stellar mass from fits to SDSS photometry is 10{sup 9.9} M{sub Sun }. They do not show a systematic offset in metallicity or mass from a redshift-matched sample of the MPA/JHU value-added catalog. In contrast to previous SN host metallicity studies, this sample is drawn from a single survey. It is also drawn from an areal rather than a targeted survey, so SNe in the lowest-mass galaxies are not systematically excluded. Indeed, the PTF SN search has a slight bias toward following up transients in low mass galaxies. The progenitor region metallicity distribution we find is statistically indistinguishable from the metallicity distribution of Type II SN hosts found by targeted surveys and by samples from multiple surveys with different selection functions. Using the relationship between iron and oxygen abundances found for Milky Way disk, bulge, and halo stars, we translate our distribution of Type II SN environments as a function of oxygen abundance into an estimate of the iron abundance, since iron varies more steeply than oxygen. We find that though this sample spans only 0.65 dex in oxygen abundance, the gap between the iron and oxygen abundance is 50% wider at the low-metallicity end of our sample than at the high-metallicity end.

Stoll, R.; Stanek, K. Z.; Pogge, R. W. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210-1173 (United States); Prieto, J. L. [Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Peyton Hall, Princeton, NJ 08544 (United States)

2013-08-10T23:59:59.000Z

163

THE STELLAR POPULATION AND STAR FORMATION RATES OF z Almost-Equal-To 1.5-1.6 [O II]-EMITTING GALAXIES SELECTED FROM NARROWBAND EMISSION-LINE SURVEYS  

SciTech Connect (OSTI)

We present the first detailed study of the stellar populations of star-forming galaxies at z {approx} 1.5, which are selected by their [O II] emission line, detected in narrowband surveys. We identified {approx}1300 [O II] emitters at z = 1.47 and z = 1.62 in the Subaru Deep Field with rest-frame equivalent widths (EWs) above 13 A. Optical and near-infrared spectroscopic observations for Almost-Equal-To 10% of our samples show that our separation of [O II] from [O III] emission-line galaxies in two-color space is 99% successful. We analyze the multi-wavelength properties of a subset of {approx}1200 galaxies with the best photometry. They have average rest-frame EW of 45 A, stellar mass of 3 Multiplication-Sign 10{sup 9} M{sub Sun }, and stellar age of 100 Myr. In addition, our spectral energy distribution (SED) fitting and broadband colors indicate that [O II] emitters span the full range of galaxy populations at z {approx} 1.5. We also find that 80% of [O II] emitters are also photometrically classified as 'BX/BM' (UV) galaxies and/or the star-forming 'BzK' (near-IR) galaxies. Our [O II] emission line survey produces a far more complete and somewhat deeper sample of z {approx} 1.5 galaxies than either the BX/BM or sBzK selection alone. We constructed average SEDs and find that higher [O II] EW galaxies have somewhat bluer continua. SED model-fitting shows that they have on average half the stellar mass of galaxies with lower [O II] EW. The observed [O II] luminosity is well correlated with the far-UV continuum with a logarithmic slope of 0.89 {+-} 0.22. The scatter of the [O II] luminosity against the far-UV continuum suggests that [O II] can be used as a star formation rate indicator with a reliability of 0.23 dex.

Ly, Chun [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Malkan, Matthew A.; Ross, Nathaniel R. [Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095 (United States); Kashikawa, Nobunari; Hayashi, Masao [Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo (Japan); Nagao, Tohru [The Hakubi Project, Kyoto University, Kyoto (Japan); Shimasaku, Kazuhiro [Department of Astronomy, School of Science, University of Tokyo, Bunkyo, Tokyo (Japan); Ota, Kazuaki, E-mail: chunly@stsci.edu [Department of Astronomy, Kyoto University, Kyoto (Japan)

2012-09-20T23:59:59.000Z

164

THE PANCHROMATIC HUBBLE ANDROMEDA TREASURY. IV. A PROBABILISTIC APPROACH TO INFERRING THE HIGH-MASS STELLAR INITIAL MASS FUNCTION AND OTHER POWER-LAW FUNCTIONS  

SciTech Connect (OSTI)

We present a probabilistic approach for inferring the parameters of the present-day power-law stellar mass function (MF) of a resolved young star cluster. This technique (1) fully exploits the information content of a given data set; (2) can account for observational uncertainties in a straightforward way; (3) assigns meaningful uncertainties to the inferred parameters; (4) avoids the pitfalls associated with binning data; and (5) can be applied to virtually any resolved young cluster, laying the groundwork for a systematic study of the high-mass stellar MF (M {approx}> 1 M {sub Sun }). Using simulated clusters and Markov Chain Monte Carlo sampling of the probability distribution functions, we show that estimates of the MF slope, {alpha}, are unbiased and that the uncertainty, {Delta}{alpha}, depends primarily on the number of observed stars and on the range of stellar masses they span, assuming that the uncertainties on individual masses and the completeness are both well characterized. Using idealized mock data, we compute the theoretical precision, i.e., lower limits, on {alpha}, and provide an analytic approximation for {Delta}{alpha} as a function of the observed number of stars and mass range. Comparison with literature studies shows that {approx}3/4 of quoted uncertainties are smaller than the theoretical lower limit. By correcting these uncertainties to the theoretical lower limits, we find that the literature studies yield ({alpha}) = 2.46, with a 1{sigma} dispersion of 0.35 dex. We verify that it is impossible for a power-law MF to obtain meaningful constraints on the upper mass limit of the initial mass function, beyond the lower bound of the most massive star actually observed. We show that avoiding substantial biases in the MF slope requires (1) including the MF as a prior when deriving individual stellar mass estimates, (2) modeling the uncertainties in the individual stellar masses, and (3) fully characterizing and then explicitly modeling the completeness for stars of a given mass. The precision on MF slope recovery in this paper are lower limits, as we do not explicitly consider all possible sources of uncertainty, including dynamical effects (e.g., mass segregation), unresolved binaries, and non-coeval populations. We briefly discuss how each of these effects can be incorporated into extensions of the present framework. Finally, we emphasize that the technique and lessons learned are applicable to more general problems involving power-law fitting.

Weisz, Daniel R.; Fouesneau, Morgan; Dalcanton, Julianne J.; Clifton Johnson, L.; Beerman, Lori C.; Williams, Benjamin F. [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); Hogg, David W.; Foreman-Mackey, Daniel T. [Center for Cosmology and Particle Physics, New York University, 4 Washington Place, New York, NY 10003 (United States)] [Center for Cosmology and Particle Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Rix, Hans-Walter; Gouliermis, Dimitrios [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany)] [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Dolphin, Andrew E. [Raytheon Company, 1151 East Hermans Road, Tucson, AZ 85756 (United States)] [Raytheon Company, 1151 East Hermans Road, Tucson, AZ 85756 (United States); Lang, Dustin [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)] [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Bell, Eric F. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States)] [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Gordon, Karl D.; Kalirai, Jason S. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)] [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Skillman, Evan D., E-mail: dweisz@astro.washington.edu [Minnesota Institute for Astrophysics, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States)

2013-01-10T23:59:59.000Z

165

EXPLORING THE LOW-MASS END OF THE M{sub BH}-{sigma}{sub *} RELATION WITH ACTIVE GALAXIES  

SciTech Connect (OSTI)

We present new measurements of stellar velocity dispersions, using spectra obtained with the Keck Echellette Spectrograph and Imager (ESI) and the Magellan Echellette (MagE), for 76 Seyfert 1 galaxies from the recent catalog of Greene and Ho. These objects were selected from the Sloan Digital Sky Survey (SDSS) to have estimated black hole (BH) masses below 2 x 10{sup 6} M{sub sun}. Combining our results with previous ESI observations of similar objects, we obtain an expanded sample of 93 galaxies and examine the relation between BH mass and velocity dispersion (the M{sub BH}-{sigma}{sub *} relation) for active galaxies with low BH masses. The low-mass active galaxies tend to follow the extrapolation of the M{sub BH}-{sigma}{sub *} relation of inactive galaxies. Including results for active galaxies of higher BH mass from the literature, we find a zero point {alpha} = 7.68 {+-} 0.08 and slope of {beta} = 3.32 {+-} 0.22 for the M{sub BH}-{sigma}{sub *} relation (in the form log M{sub BH} = {alpha} + {beta}log ({sigma}{sub *}/200 km s{sup -1})), with intrinsic scatter of 0.46 {+-} 0.03 dex. This result is consistent, within the uncertainties, with the slope of the M{sub BH}-{sigma}{sub *} relation for reverberation-mapped active galaxies with BH masses from 10{sup 6} to 10{sup 9} M{sub sun}. For the subset of our sample having morphological information from Hubble Space Telescope images, we examine the slope of the M{sub BH}-{sigma}{sub *} relation separately for subsamples of barred and unbarred host galaxies, and find no significant evidence for a difference in slope. We do find a mild offset between low-inclination and high-inclination disk galaxies, such that more highly inclined galaxies tend to have larger {sigma}{sub *} at a given value of BH mass, presumably due to the contribution of disk rotation within the spectroscopic aperture. We also find that the velocity dispersion of the ionized gas, measured from narrow emission lines including [N II] {lambda}6583, [S II] {lambda}{lambda}6716, 6731, and the core of [O III] {lambda}5007 (with the blueshifted wing removed), trace the stellar velocity dispersion well for this large sample of low-mass Seyfert 1 galaxies.

Xiao Ting [Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026 (China); Barth, Aaron J. [Department of Physics and Astronomy, University of California at Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697-4575 (United States); Greene, Jenny E.; Ludwig, Randi R. [University of Texas at Austin, Department of Astronomy, 1 University Station, C1400, Austin, TX 78712-0259 (United States); Ho, Luis C. [The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Bentz, Misty C. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, One Park Place South SE, Suite 700, Atlanta, GA 30303 (United States); Jiang Yanfei, E-mail: xiaoting@mail.ustc.edu.cn, E-mail: barth@uci.edu, E-mail: jgreene@astro.as.utexas.edu, E-mail: lho@obs.carnegiescience.edu, E-mail: bentz@chara.gsu.edu, E-mail: yanfei@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2011-09-20T23:59:59.000Z

166

A study of the market structure of the United States' rice industry  

E-Print Network [OSTI]

, ;industry ag organisation and . pcx'for~ . , ", :, ::*;; ?"'. . . ' ', ', 'I 7 elauce'' - Rsrshal. lian ' 9'Ad neo' marsha1. liisn theorist'8 iI"'::-;:-': -'. 'dex. 'vied theories sb'auk' the. pex formanoe of an industry. . hhar'-';, ":-'-;-, ' ;- @uter..."end pioneering eontribbtion by an adaptation of the . theory oZ imperCeet. ceapetition develops'd by a~xlin-, ? Robinsbn, "-Triggin"and others '', to the:agrieultiiial-'proc'esjsing add-'=d+trxbnting. , indnstx', iesi '. jxn resent -ye'ars:, :-;:;xeaaarjh...

Farruk, Muhammad Osman

2012-06-07T23:59:59.000Z

167

NERSC Computer Security  

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 Conchas recovery challengeMultiscale SubsurfaceExascale Era Computing » CoDEx

168

NERSC Consulting services  

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 Conchas recovery challengeMultiscale SubsurfaceExascale Era Computing » CoDExConsulting

169

In Colombia  

E-Print Network [OSTI]

28 LATIN AMERICAN THEATRE REVIEW In Colombia Muestras Regionales de Teatro. 95 groups presented plays in Bogot, Cali, Barranquilla, Bucaramanga and Medellin between September 1 and 7, 1975. Festival Nacional del Nuevo Teatro. October 6-17, 1975...

1975-10-01T23:59:59.000Z

170

High Dispersion Spectroscopy of Solar-type Superflare Stars. I. Temperature, Surface Gravity, Metallicity, and $v \\sin i$  

E-Print Network [OSTI]

We conducted high dispersion spectroscopic observations of 50 superflare stars with Subaru/HDS, and measured the stellar parameters of them. These 50 targets were selected from the solar-type (G-type main sequence) superflare stars that we had discovered from the Kepler photometric data. As a result of these spectroscopic observations, we found that more than half (34 stars) of our 50 targets have no evidence of binary system. We then estimated effective temperature ($T_{\\rm{eff}}$), surface gravity ($\\log g$), metallicity ([Fe/H]), and projected rotational velocity ($v\\sin i$) of these 34 superflare stars on the basis of our spectroscopic data. The accuracy of our estimations is higher than that of Kepler Input Catalog (KIC) values, and the differences between our values and KIC values ($(\\Delta T_{\\rm{eff}})_{\\rm{rms}} \\sim 219$K, $(\\Delta \\log g)_{\\rm{rms}} \\sim 0.37$ dex, and $(\\Delta\\rm{[Fe/H]})_{\\rm{rms}} \\sim 0.46$ dex) are comparable to the large uncertainties and systematic differences of KIC values ...

Notsu, Yuta; Maehara, Hiroyuki; Notsu, Shota; Shibayama, Takuya; Nogami, Daisaku; Shibata, Kazunari

2014-01-01T23:59:59.000Z

171

In Focus  

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 Jun Jul(Summary)morphinanInformation Desert Southwest Region service area.Portaldefault Sign In About |ImagingIn Case ofIn

172

In progress  

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 withconfinementEtching.348 270 300Aptamers andIn other news

173

In progress  

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 withconfinementEtching.348 270 300Aptamers andIn other newsNo data available!

174

THE MASS DEPENDENCE BETWEEN PROTOPLANETARY DISKS AND THEIR STELLAR HOSTS  

SciTech Connect (OSTI)

We present a substantial extension of the millimeter (mm) wave continuum photometry catalog for circumstellar dust disks in the Taurus star-forming region, based on a new ''snapshot'' {lambda} = 1.3 mm survey with the Submillimeter Array. Combining these new data with measurements in the literature, we construct a mm-wave luminosity distribution, f(L{sub mm}), for Class II disks that is statistically complete for stellar hosts with spectral types earlier than M8.5 and has a 3{sigma} depth of roughly 3 mJy. The resulting census eliminates a longstanding selection bias against disks with late-type hosts, and thereby demonstrates that there is a strong correlation between L{sub mm} and the host spectral type. By translating the locations of individual stars in the Hertzsprung-Russell diagram into masses and ages, and adopting a simple conversion between L{sub mm} and the disk mass, M{sub d} , we confirm that this correlation corresponds to a statistically robust relationship between the masses of dust disks and the stars that host them. A Bayesian regression technique is used to characterize these relationships in the presence of measurement errors, data censoring, and significant intrinsic scatter: the best-fit results indicate a typical 1.3 mm flux density of {approx}25 mJy for 1 M{sub Sun} hosts and a power-law scaling L{sub mm}{proportional_to}M{sub *}{sup 1.5-2.0}. We suggest that a reasonable treatment of dust temperature in the conversion from L{sub mm} to M{sub d} favors an inherently linear M{sub d} {proportional_to}M{sub *} scaling, with a typical disk-to-star mass ratio of {approx}0.2%-0.6%. The measured rms dispersion around this regression curve is {+-}0.7 dex, suggesting that the combined effects of diverse evolutionary states, dust opacities, and temperatures in these disks imprint a full width at half-maximum range of a factor of {approx}40 on the inferred M{sub d} (or L{sub mm}) at any given host mass. We argue that this relationship between M{sub d} and M{sub *} likely represents the origin of the inferred correlation between giant planet frequency and host star mass in the exoplanet population, and provides some basic support for the core accretion model for planet formation. Moreover, we caution that the effects of incompleteness and selection bias must be considered in comparative studies of disk evolution, and illustrate that fact with statistical comparisons of f(L{sub mm}) between the Taurus catalog presented here and incomplete subsamples in the Ophiuchus, IC 348, and Upper Sco young clusters.

Andrews, Sean M.; Rosenfeld, Katherine A.; Kraus, Adam L.; Wilner, David J., E-mail: sandrews@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2013-07-10T23:59:59.000Z

175

STELLAR DIAMETERS AND TEMPERATURES. II. MAIN-SEQUENCE K- AND M-STARS  

SciTech Connect (OSTI)

We present interferometric angular diameter measurements of 21 low-mass, K- and M-dwarfs made with the CHARA Array. This sample is enhanced by adding a collection of radius measurements published in the literature to form a total data set of 33 K-M-dwarfs with diameters measured to better than 5%. We use these data in combination with the Hipparcos parallax and new measurements of the star's bolometric flux to compute absolute luminosities, linear radii, and effective temperatures for the stars. We develop empirical relations for {approx}K0 to M4 main-sequence stars that link the stellar temperature, radius, and luminosity to the observed (B - V), (V - R), (V - I), (V - J), (V - H), and (V - K) broadband color index and stellar metallicity [Fe/H]. These relations are valid for metallicities ranging from [Fe/H] = -0.5 to +0.1 dex and are accurate to {approx}2%, {approx}5%, and {approx}4% for temperature, radius, and luminosity, respectively. Our results show that it is necessary to use metallicity-dependent transformations in order to properly convert colors into stellar temperatures, radii, and luminosities. Alternatively, we find no sensitivity to metallicity on relations we construct to the global properties of a star omitting color information, e.g., temperature-radius and temperature-luminosity. Thus, we are able to empirically quantify to what order the star's observed color index is impacted by the stellar iron abundance. In addition to the empirical relations, we also provide a representative look-up table via stellar spectral classifications using this collection of data. Robust examinations of single star temperatures and radii compared to evolutionary model predictions on the luminosity-temperature and luminosity-radius planes reveal that models overestimate the temperatures of stars with surface temperatures <5000 K by {approx}3%, and underestimate the radii of stars with radii <0.7 R{sub Sun} by {approx}5%. These conclusions additionally suggest that the models over account for the effects that the stellar metallicity may have on the astrophysical properties of an object. By comparing the interferometrically measured radii for the single star population to those of eclipsing binaries, we find that for a given mass, single and binary star radii are indistinguishable. However, we also find that for a given radius, the literature temperatures for binary stars are systematically lower compared to our interferometrically derived temperatures of single stars by {approx}200 to 300 K. The nature of this offset is dependent on the validation of binary star temperatures, where bringing all measurements to a uniform and correctly calibrated temperature scale is needed to identify any influence stellar activity may have on the physical properties of a star. Lastly, we present an empirically determined H-R diagram using fundamental properties presented here in combination with those in Boyajian et al. for a total of 74 nearby, main-sequence, A- to M-type stars, and define regions of habitability for the potential existence of sub-stellar mass companions in each system.

Boyajian, Tabetha S.; McAlister, Harold A.; Jones, Jeremy; White, Russel; Henry, Todd; Gies, Douglas; Jao, Wei-Chun; Parks, J. Robert [Center for High Angular Resolution Astronomy and Department of Physics and Astronomy, Georgia State University, P.O. Box 4106, Atlanta, GA 30302-4106 (United States); Von Braun, Kaspar; Kane, Stephen R.; Ciardi, David [NASA Exoplanet Science Institute, California Institute of Technology, MC 100-22, Pasadena, CA 91125 (United States); Van Belle, Gerard [Lowell Observatory, Flagstaff, AZ 86001 (United States); Ten Brummelaar, Theo A.; Schaefer, Gail; Sturmann, Laszlo; Sturmann, Judit [The CHARA Array, Mount Wilson Observatory, Mount Wilson, CA 91023 (United States); Muirhead, Philip S. [Department of Astronomy, California Institute of Technology, 1200 East California Boulevard, MC 249-17, Pasadena, CA 91125 (United States); Lopez-Morales, Mercedes [Institut de Ciencies de L'Espai (CSIC-IEEC), E-08193 Bellaterra (Spain); Ridgway, Stephen [National Optical Astronomy Observatory, P.O. Box 26732, Tucson, AZ 85726-6732 (United States); Rojas-Ayala, Barbara [Department of Astrophysics, Division of Physical Sciences, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States); and others

2012-10-01T23:59:59.000Z

176

Environmental Radioactivity in Greenland in 1981  

E-Print Network [OSTI]

Ris-R-471 v Environmental Radioactivity in Greenland in 1981 A. Aarkrog, Henning Dahlgaard, Elis July 1962 #12;Ris-R-471 ENVIRONMENTAL RADIOACTIVITY IN GREENLAND IN 1981 A. Aarkrog, Henning Dahlgaard. Measurements of fallout radioactivity in Greenland in 1981 are reported. Strontium-90 (and Cesium-137 in most

177

Environmental Radioactivity in Greenland in 1978  

E-Print Network [OSTI]

ft I la 0 0 0 0 Risn-R-405 Environmental Radioactivity in Greenland in 1978 A. Aarkrog, Heinz ENVIRONMENTAL RADIOACTIVITY IN GREENLAND IN 1978 A. Aarkrog, Heinz Hansen and J. Lippert Abstract. Heasureaents of fallout radioactivity in Greenland in 1978 are reported. Strontium-90 (and Cesium-137 in most cases

178

THE MASSIVE SATELLITE POPULATION OF MILKY-WAY-SIZED GALAXIES  

SciTech Connect (OSTI)

Several occupational distributions for satellite galaxies more massive than m{sub *} Almost-Equal-To 4 Multiplication-Sign 10{sup 7} M{sub Sun} around Milky-Way (MW)-sized hosts are presented and used to predict the internal dynamics of these satellites as a function of m{sub *}. For the analysis, a large galaxy group mock catalog is constructed on the basis of (sub)halo-to-stellar mass relations fully constrained with currently available observations, namely the galaxy stellar mass function decomposed into centrals and satellites, and the two-point correlation functions at different masses. We find that 6.6% of MW-sized galaxies host two satellites in the mass range of the Small and Large Magellanic Clouds (SMC and LMC, respectively). The probabilities of the MW-sized galaxies having one satellite equal to or larger than the LMC, two satellites equal to or larger than the SMC, or three satellites equal to or larger than Sagittarius (Sgr) are Almost-Equal-To 0.26, 0.14, and 0.14, respectively. The cumulative satellite mass function of the MW, N{sub s} ({>=}m{sub *}) , down to the mass of the Fornax dwarf is within the 1{sigma} distribution of all the MW-sized galaxies. We find that MW-sized hosts with three satellites more massive than Sgr (as the MW) are among the most common cases. However, the most and second most massive satellites in these systems are smaller than the LMC and SMC by roughly 0.7 and 0.8 dex, respectively. We conclude that the distribution N{sub s} ({>=}m{sub *}) for MW-sized galaxies is quite broad, the particular case of the MW being of low frequency but not an outlier. The halo mass of MW-sized galaxies correlates only weakly with N{sub s} ({>=}m{sub *}). Then, it is not possible to accurately determine the MW halo mass by means of its N{sub s} ({>=}m{sub *}); from our catalog, we constrain a lower limit of 1.38 Multiplication-Sign 10{sup 12} M{sub Sun} at the 1{sigma} level. Our analysis strongly suggests that the abundance of massive subhalos should agree with the abundance of massive satellites in all MW-sized hosts, i.e., there is not a missing (massive) satellite problem for the {Lambda}CDM cosmology. However, we confirm that the maximum circular velocity, v{sub max}, of the subhalos of satellites smaller than m{sub *} {approx} 10{sup 8} M{sub Sun} is systematically larger than the v{sub max} inferred from current observational studies of the MW bright dwarf satellites; different from previous works, this conclusion is based on an analysis of the overall population of MW-sized galaxies. Some pieces of evidence suggest that the issue could refer only to satellite dwarfs but not to central dwarfs, then environmental processes associated with dwarfs inside host halos combined with supernova-driven core expansion should be on the basis of the lowering of v{sub max}.

Rodriguez-Puebla, Aldo; Avila-Reese, Vladimir; Drory, Niv, E-mail: apuebla@astro.unam.mx [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, A. P. 70-264, 04510 Mexico, DF (Mexico)

2013-08-20T23:59:59.000Z

179

Study in Germany / Work in Germany  

E-Print Network [OSTI]

Study in Germany / Work in Germany Opportunities Prof. Dr. Silke R. Falkner German Programme Coordinator silke.falkner@usask.ca Tel.: 966-5744 #12;Content I. Opportunities for Study in Germany II. German in Germany V. Term II courses #12;I.A. Study in Germany (Summer) 1. CSSG: Canadian Summer School in Germany

Peak, Derek

180

Iran in History Iran in History  

E-Print Network [OSTI]

1 Iran in History Iran in History by Bernard Lewis In attempting to attain some perspective on Iran. These events have been variously seen in Iran: by some as a blessing, the advent of the true faith, the end remarkable difference between what happened in Iran and what happened in all the other countries

Mohaghegh, Shahab

Note: This page contains sample records for the topic "antiknock in dex" 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.
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to obtain the most current and comprehensive results.


181

Essays in Applied Microeconomics  

E-Print Network [OSTI]

mobilize to build aluminum smelters in the Northwest. ALCOAthe property for a smelter in Longview, Washington, in 1940.the Longview facility. The smelter opened in September 1941,

Severnini, Edson Roberto

2013-01-01T23:59:59.000Z

182

Popular Theatre in Ethiopia  

E-Print Network [OSTI]

bqinninl oflbeltte in Ethiopia] . (trans. from Amlwie), (such community theatre in Ethiopia with special reference tocommunity development in Ethiopia will be pro posed in th e

Ashagrie, Aboneh

1996-01-01T23:59:59.000Z

183

Environmental Radioactivity in Denmark in 1983  

E-Print Network [OSTI]

, potatoes, vegetables, (continued) INIS-Descriptors: AIR; AMERICIUM ISOTOPES; AQUATIC ECOSYSTEMS; AT was determined in precipitation, ground water and sea water. Plutonium and Americium were measured in marine

184

State Experience in Hydrogen Infrastructure in California  

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

Experience in Hydrogen Infrastructure in California Gerhard H Achtelik Jr. February 17, 2011 Hydrogen Infrastructure Market Readiness Workshop California Environmental Protection...

185

Petroleum developments in North Africa in 1979  

SciTech Connect (OSTI)

In the 6 countries covered by this report, the extent of valid petroleum rights, seismic work, and drilling was nearly the same as in 1978. The success rate of wildcat drilling decreased slightly, to 28% (33% in 1978), with 26 oil or gas discoveries. In southwestern Tunisia, the Amoco Sabrina Nord 1 tested 930 bbl of 39/sup 0/ APl oil from Cambrian-Ordovician sandstones - the first oil to come from lower Paleozoic rocks in Tunisia. First commercial oil from Cambrian-Ordovician rocks in western Libya was discovered by Agip A1-NC40 which flowed 1,400 b/d. Highlight of the year in North Africa was in the interior basin of Sudan where the Chevron Abu Gabra 1 tested 900 BOPD of 40/sup 0/ APl oil from Cretaceous rocks; 2 other wells, spudded in late 1979 in the same area, have tested 3,200 and 7,300 b/d, respectively, in early 1980. Discovery well of the interior basin was Chevron Unity 1 which tested small amounts of oil in 1978. Oil production in North Africa in 1979 averaged 3,939,500 b/d compared with 3,802,800 b/d in 1978, an increase of 3.6%.

Nicod, M.A.

1980-11-01T23:59:59.000Z

186

Essays in behavioral economics  

E-Print Network [OSTI]

Essays in Behavioral Economics A dissertation submitted inDoctor of Philosophy in Economics by David Holding Eilfunction, The Review of Economics and Statistics, 1995,

Eil, David Holding

2011-01-01T23:59:59.000Z

187

Political Risk in Finland.  

E-Print Network [OSTI]

?? Thesis political risk in Finland will explain the real nature of the financial crisis in Finland in the beginning of 1990s. Before 1990s Finland (more)

Davidsson, Jukka

2007-01-01T23:59:59.000Z

188

Essays in Economics  

E-Print Network [OSTI]

Kingdom in Ancient Egypt Introduction . . . . . . . . . .D. and E. Teeter (2007). Egypt and the Egyptians. Cambridge:of the State in Ancient Egypt. Explorations in Economic

Romem, Israel Hadas

2013-01-01T23:59:59.000Z

189

Vortices in Brain waves  

E-Print Network [OSTI]

2003). Vortices in Brain Waves 62. M. E. Raichle, ScienceVORTICES IN BRAIN WAVES WALTER J. FREEMAN Department ofthat is recorded in brain waves (electroencephalogram, EEG).

Freeman, Walter J III; Vitiello, Giuseppe

2010-01-01T23:59:59.000Z

190

Feed-in Tariff  

Broader source: Energy.gov [DOE]

In September 2009, the Hawaii Public Utilities Commission (PUC) issued a decision that established a feed-in tariff in Hawaii. The feed-in tariff is offered by the three investor-owned utilities:...

191

in partnership Partnerships  

E-Print Network [OSTI]

and difference: populations of African descent in Mexico and Central America", in Mexico. Study of the Humboldt, in Argentina. Conference on metal pollution and its impact on the environment, health and society, in Bolivia

192

Essays in labor economics  

E-Print Network [OSTI]

I addressed three questions in Labor Economics, using experimental and quasi-experimental variation to determine causality. In the first chapter, I ask whether playing longer in the NFL increases mortality in retirement. ...

Williams, Tyler (Tyler Kenneth)

2013-01-01T23:59:59.000Z

193

Developments in oil shale in 1987  

SciTech Connect (OSTI)

Oil shale development continued at a slow pace in 1987. The continuing interest in this commodity is demonstrated by the 342 oil shale citations added to the US Department of Energy Energy Database during 1987. The Unocal project in Parachute, Colorado, produced 600,000 bbl of synfuel in 1987. An appreciable amount of 1987's activity was associated with the nonsynfuel uses of oil shale. 4 figs., 2 tabs.

Knutson, C.F.; Dana, G.F.; Solti, G.; Qian, J.L.; Ball, F.D.; Hutton, A.C.; Hanna, J.; Russell, P.L.; Piper, E.M.

1988-10-01T23:59:59.000Z

194

DIFFUSION IN SOLIDSDIFFUSION IN SOLIDS FICK'S LAWS  

E-Print Network [OSTI]

Diffusion bonding To comprehend many materials related phenomenon one must understand Diffusion. The focusDIFFUSION IN SOLIDSDIFFUSION IN SOLIDS FICK'S LAWS KIRKENDALL EFFECT ATOMIC MECHANISMS Diffusion in Solids P.G. Shewmon McGraw-Hill, New York (1963) #12;Oxidation Roles of Diffusion Creep Aging

Subramaniam, Anandh

195

Magnetic rotation in {sup 112}In  

SciTech Connect (OSTI)

The high spin states of {sup 112}In have been investigated with in-beam {gamma}-ray spectroscopic methods using the {sup 110}Pd({sup 7}Li,5n){sup 112}In reaction at a beam energy of 50 MeV. A level scheme with three band structures has been established and their configurations are discussed. The positive-parity dipole band has been assigned as a magnetic rotation band. Particle-rotor model calculations have also been performed to interpret the rotational structures in {sup 112}In.

He, C. Y.; Li, X. Q.; Wu, X. G.; Liu, Y.; Pan, B.; Li, G. S.; Li, L. H.; Wang, Z. M. [China Institute of Atomic Energy, Beijing 102413 (China); Zhu, L. H. [School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); School of Science, Shenzhen University, Shenzhen 518060 (China); Qi, B.; Wang, S. Y. [School of Space Science and Physics, Shandong University at Weihai, Weihai 264209 (China); Li, Z. Y. [School of Physics and SK Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Xu, Q.; Wang, J. G.; Ding, H. B. [Department of Physics, Tsinghua University, Beijing 100084 (China); Zhai, J. [Department of Physics, Jilin University, Changchun 130023 (China)

2011-02-15T23:59:59.000Z

196

Oscillations in glow discharges  

E-Print Network [OSTI]

OSCILLATIONS IN GLOW DISCHARGES A Dissertation By Tom Prickett, Jr. June 1950 Approved as to style and content by Chairman of Committee OSCILLATIONS IN GLOW DISCHARGES A Dissertation By Tom Prickett, Jr* June 1950 OSCILLATIONS IN GLOW... 1950 CONTENTS Introduction ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 1 I. Review of Plasma Oscillations in Gas Discharges ? . . 2 II. Review of Relaxation Processes in Gas Discharges ? . 13 III. Report of Laboratory Investigation...

Prickett, Tom

1950-01-01T23:59:59.000Z

197

In partners EXTENSION CE  

E-Print Network [OSTI]

service Minnesota Local egetables i directors i a n in #12;LOCAL FOOD MARKET IN HEALTHCARE FRUITS AND VEGETABLES IN HEALTHCARE INSTITUTIONS BASED ON A SURVEY OF FOOD SERVICE DIRECTORS IN BECKER of Minnesota Extension conducted a survey of food service directors in Becker, Clay, Otter Tail, and Wilkin

Ciocan-Fontanine, Ionut

198

Oats in Texas.  

E-Print Network [OSTI]

of a plant and \\ restricts the yield. Late grazing usually re- duces yield. In general, oats should not be I grazed after February 20 in Area 4 (figure 1.) ; February 28 in Area 3; March 5 in Area 2 and ' \\Inrrh 10 in Area 1. Early...

Spears, Ben; Coffey, Lee

1957-01-01T23:59:59.000Z

199

New Developments in GIS in Water Resources  

E-Print Network [OSTI]

Standardized formats Data: Dynamic in time Simple in space (points) No standardized formats What is Hydro? Hydrology Hydrography Circulation of the waters of the earth through the hydrologic cycle The blue lines on maps Properties of Water... of query functions Returns data in WaterML Services-Oriented Architecture for Water Data Links geographically distributed information servers through internet Web Services Description Language (WSDL from W3C) We designed WaterML as a web...

Maidment, David

2008-11-19T23:59:59.000Z

200

In situ combustion field experiences in Venezuela  

SciTech Connect (OSTI)

A literature review of four in situ combustion projects: in Miga, Tia Juana, Melones and Morichal fields in Venezuela was made, and a summary of these projects is presented. Reservoir description and project performance data were analyzed. The behavior of the four in situ combustion field tests can be summarized as follows: The problems most often encountered were corrosion and high temperature producing wells. The direction in which the burning front moved was guided essentially by reservoir characteristics. The produced oil was upgraded by about 4{degrees} API, and viscosity was substantially reduced. For Mirochal and Miga fields, the analyses of available information from the combustion projects indicated that the process has been successful in the affected region. Conclusions from this review indicate that the two most frequent problems encountered were operational problems in producing wells and the direction of the burning front. The heterogeneous nature of the sands probably resulted in the burning front moving in a preferential direction, hence reducing areal sweep efficiency.

Villalba, M.; Estrada, M.; Bolivar, J. [INTEVEP, Caracas (Venezuela)

1995-02-01T23:59:59.000Z

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While these samples are representative of the content of NLEBeta,
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to obtain the most current and comprehensive results.


201

UF in Osnabrck Understanding Engineering in Europe  

E-Print Network [OSTI]

the chance to climb a 100 meter tall wind generator tower! About the Location Osnabrück is located in Lower

Jawitz, James W.

202

Change in Contaminant Concentration in Fraser  

E-Print Network [OSTI]

during this period: dioxins, furans, polycyclic aromatic hydrocarbons (PAHs), chlorophenolics, resin to the peak in suspended sediment concentration during the freshet sampling period, iv) dioxins

203

Homeless in America, Homeless in California  

E-Print Network [OSTI]

418438. Mansur, Erin, John M. Quigley, Steven Raphael, andHOMELESS IN CALIFORNIA John M. Quigley, Steven Raphael, and

Quigley, John M.; Raphael, Steven; Smolensky, Eugene

2002-01-01T23:59:59.000Z

204

GEOPHYSICAL METHODS In 2003, a group of scientists in Swit-  

E-Print Network [OSTI]

with Petrobras in Brazil, Pemex in Mexico, Norsk Hydro in Libya and KOC in the Arabian Peninsula, it is evident

Podladchikov, Yuri

205

Essays in Regulatory Economics  

E-Print Network [OSTI]

of regular and premium gasoline of gas station i at month t,the Mexican gasoline market, all gas stations are franchisesdecreases in gasoline demand in gas stations exposed in the

Guerrero, Santiago

2011-01-01T23:59:59.000Z

206

PCs in Business Environment  

E-Print Network [OSTI]

"PCs in Business Environment" is a project that contains two parts. First part is a real life application developed for Nordic Meat Inc. a small food - manufacturer in the KC area, developed in MS Excel 5.0 spreadsheet ...

Colak, Mijo Todor

1994-07-29T23:59:59.000Z

207

Exceptional Situations in Lisp  

E-Print Network [OSTI]

Frequently, it is convenient to describe a program in terms of the normal situations in which it will be used, even if such a description does not describe the its complete behavior in all circumstances. This paper surveys ...

Pitman, Kent M.

208

Bacteria in shear flow  

E-Print Network [OSTI]

Bacteria are ubiquitous and play a critical role in many contexts. Their environment is nearly always dynamic due to the prevalence of fluid flow: creeping flow in soil, highly sheared flow in bodily conduits, and turbulent ...

Marcos, Ph.D. Massachusetts Institute of Technology

2011-01-01T23:59:59.000Z

209

ILLEGAL LOGGING IN INDONESIA  

E-Print Network [OSTI]

ILLEGAL LOGGING IN INDONESIA THE ENVIRONMENTAL, ECONOMIC AND SOCIAL COSTS #12;ILLEGAL LOGGING IN INDONESIA THE ENVIRONMENTAL, ECONOMIC AND SOCIAL COSTS Contents Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 #12;ILLEGAL LOGGING IN INDONESIA | 2 Executive Summary Indonesia's rainforests are the third

210

Essays in organizational economics  

E-Print Network [OSTI]

The first chapter examines the interaction of heterogeneous firms in a competitive market in which firms motivate their workers using relational incentive contracts. In the steady-state rational-expectations equilibrium, ...

Powell, Michael Leslie

2011-01-01T23:59:59.000Z

211

Dynamics in Formal Argumentation  

E-Print Network [OSTI]

by constructing and weighing up arguements intended to give support in favour or against alternative conclusions. In dynamic argumentation, such arguements may be revised and strengthened in order yo increase to decrease the acceptability of controversial...

Carbogim, Daniela Vasconcelos

212

Foreign Deities in Egypt  

E-Print Network [OSTI]

fig. 211. ) Foreign Deities in Egypt, Zivie-Coche, UEE 2011god Hauron and his cult in Egypt. Gttinger Miszellen 107,2011, Foreign Deities in Egypt. UEE. Full Citation: Zivie-

Zivie-Coche, Christiane

2011-01-01T23:59:59.000Z

213

Corruption in Developing Countries  

E-Print Network [OSTI]

Recent years have seen a remarkable expansion in economists' ability to measure corruption. This in turn has led to a new generation of well-identified, microeconomic studies. We review the evidence on corruption in ...

Olken, Benjamin A.

214

Symmetries in physics  

E-Print Network [OSTI]

The concept of symmetries in physics is briefly reviewed. In the first part of these lecture notes, some of the basic mathematical tools needed for the understanding of symmetries in nature are presented, namely group theory, Lie groups and Lie algebras, and Noether's theorem. In the second part, some applications of symmetries in physics are discussed, ranging from isospin and flavor symmetry to more recent developments involving the interacting boson model and its extension to supersymmetries in nuclear physics.

Roelof Bijker

2005-09-02T23:59:59.000Z

215

Essays in Development Economics  

E-Print Network [OSTI]

are weak, Review of Economics and Statistics, 2004, 86,Essays in Development Economics A dissertation submitted indegree Doctor of Philosophy in Economics by Samuel Ali Bazzi

Bazzi, Samuel Ali

216

Advances in NMR Methodology  

E-Print Network [OSTI]

to masking tape, before casting in epoxy resin . . . . .material, such as epoxy resin, changing the concentration ofbefore casting in epoxy resin the magnetic permeability of

Trease, David Richard

2010-01-01T23:59:59.000Z

217

Solar Heating in Uppsala.  

E-Print Network [OSTI]

?? The housing corporation Uppsalahem has installed asolar heating system in the neighbourhood Haubitsen,which was renovated in 2011. This report examineshow much energy the solar (more)

Blomqvist, Emelie; Hger, Klara

2012-01-01T23:59:59.000Z

218

Complexity in Big History  

E-Print Network [OSTI]

Spier, Fred. How Big History Works: Energy Flows and RiseSmil, Vaclav. Energy in World History. Boulder, CO: Westviewkg) Energy and complexity Spier: Complexity in Big History.

Spier, Fred

2011-01-01T23:59:59.000Z

219

Essays in Environmental Economics  

E-Print Network [OSTI]

Kings County . . . . . . . . . . . . . . . . . . . . . . . . . . .farm workers, while Kings County has the lowest in bothfor example in Kern and Kings Counties. To illustrate this

Foreman, Kathleen

2013-01-01T23:59:59.000Z

220

Essays in Economics  

E-Print Network [OSTI]

Housing prices in King County . . . . . . . . . Empiricaldata from 2007 to 2011 on King County, WA (metro Seattle), Iproprietary data on homes in King County, Washington (metro

Romem, Israel Hadas

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "antiknock in dex" 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

QUANTUM CONVERSION IN PHOTOSYNTHESIS  

E-Print Network [OSTI]

QUANTUM CONVERSION IN PHOTOSYNTHESIS Melvin Calvin Januaryas it occurs in modern photosynthesis can only take place inof the problem or photosynthesis, or any specific aspect of

Calvin, Melvin

2008-01-01T23:59:59.000Z

222

Reversible phosphorylation in mitochondria  

E-Print Network [OSTI]

protein OM Outer membrane PDC Pyruvate dehydrogenase complexdehydrogenase complex (PDC). Polyclonal antibodies wereantibodies can detect changes in PDC activity in response to

Rardin, Matthew James

2008-01-01T23:59:59.000Z

223

Interconnect Issues in NE  

Broader source: Energy.gov [DOE]

Presentation covers interconnect issues in the Northeast and is given at the Spring 2010 Federal Utility Partnership Working Group (FUPWG) meeting in Providence, Rhode Island.

224

In PDF format  

E-Print Network [OSTI]

mappings by letting a point a in the interior split into two and travel to two ..... holomorphic in a neighborhood of ?. The Ahlfors map g extends holomorphically.

1911-00-51T23:59:59.000Z

225

Demand Response In California  

Broader source: Energy.gov [DOE]

Presentation covers the demand response in California and is given at the FUPWG 2006 Fall meeting, held on November 1-2, 2006 in San Francisco, California.

226

"Clean solutions; in research and in education."  

E-Print Network [OSTI]

of flexibility Carbon-Fiber Composites A project in our lab has resulted in the development of a carbon-fiber information please view the video from the carbon fiber jet engine plant recently opened on the Isle of Wight; multifunctional heat-pipes; manufacturing of complex carbon composite objects and improvement of STEM education

Acton, Scott

227

Individual variation in cooperative behaviour in meerkats  

E-Print Network [OSTI]

on the behaviour partly because of this benefit (West et al., 2007). Darwin (1859) identified cooperation in the form of sterile workers in social insects as representing one special diffi culty posed to his theory of evolution by natural selection (p. 236...

English, Sinad

2010-04-13T23:59:59.000Z

228

203Literature in Translation LITERATURE IN  

E-Print Network [OSTI]

(Classics 201) (3)-- Classical Mythology An introduction to the study of Greek and Roman mythology in Translation 218 (3)-- Pre-Modern Chinese Literature in Translation A survey of Chinese literature from historical and cultural contexts from pre-modern to modern times

Dresden, Gregory

229

Advances in iridium alloy processing in 1987  

SciTech Connect (OSTI)

A new process for the production of DOP-26 iridium alloy blanks is being evaluated and optimized. The alloy is prepared by electron-beam (EB) melting of Ir-0.3% W powder compacts followed by doping with aluminum and thorium by arc melting. Drop-cast alloy rod segments are EB welded to produce an electrode that is consumable arc melted to produce an ingot for extrusion and subsequent rolling. Initial results showed rejections for ultrasonic indications of alloy blanks produced by this process to be very low. Subsequently, some ingots have exhibited delaminations in the sheet, leading to rejection rates similar to that obtained in the standard process. The increase in delaminations is related to near-surface porosity in the consumable arc-melted ingot. A number of modifications to the arc-melting process and plans for further experimental work are described. In addition, the tensile properties of the DOP-26 iridium alloys have been measured over a range of test temperatures and strain rates. A laboratory evaluation of alternative cleaning procedures indicates that electrolytic dissolution of DOP-26 iridium alloy in an HCl solution is a potential substitute to the KCN process now in use. 7 refs., 13 figs., 6 tabs.

Heestand, R.L.; Ohriner, E.K.; Roche, T.K.

1988-08-01T23:59:59.000Z

230

RESEARCH IN PARTICLE PHYSICS  

SciTech Connect (OSTI)

This is the final report for the Department of Energy Grant to Principal Investigators in Experimental and Theoretical Particle Physics at Boston University. The research performed was in the Energy Frontier at the LHC, the Intensity Frontier at Super-Kamiokande and T2K, the Cosmic Frontier and detector R&D in dark matter detector development, and in particle theory.

Kearns, Edward [Boston Universiy] [Boston Universiy

2013-07-12T23:59:59.000Z

231

Graduate Certificate in Transportation  

E-Print Network [OSTI]

Graduate Certificate in Transportation Nohad A. Toulan School of Urban Studies and Planning of Engineering and Computer Science integrated transportation systems. The Graduate Certificate in Transportation their capabilities. Students in the program can choose among a wide range of relevant courses in transportation

Bertini, Robert L.

232

Reading context in design  

E-Print Network [OSTI]

This study explores how, in the process of design, the reading of an existing order in the organizing features of a setting potentiates form. For this purpose, a design exercise on a site in the city of Jaipur in India has ...

Agrawal, Vivek

1993-01-01T23:59:59.000Z

233

study programs in mathematics  

E-Print Network [OSTI]

study programs in m mathematics #12;#12;3 CONTENTS 5 Introduction 7 Mathematics at the University of Ljubljana 9 Department of Mathematics information page Academic study program in Mathematics Academic study program in Financial Mathematics Single cycle master's study program in Mathematics education

?umer, Slobodan

234

Minor in Philosophy Requirements  

E-Print Network [OSTI]

2012-05-23 Minor in Philosophy Requirements: 1. 18 hours of work in philosophy with grades of C- or better. 2. A 2.0 grade point average for all work attempted in philosophy. 3. 9 hours of upper division work in philosophy, with grades of C- or better. 4. Completion of at least one course, with a grade

Stowell, Michael

235

IN TODAY'S PAPER International  

E-Print Network [OSTI]

India's participation in the multi-billion-dollar International Thermonuclear Reactor project which aims

236

Nuclear spirals in galaxies  

E-Print Network [OSTI]

Recent high-resolution observations indicate that nuclear spirals are often present in the innermost few hundred parsecs of disc galaxies. My models show that nuclear spirals form naturally as a gas response to non-axisymmetry in the gravitational potential. Some nuclear spirals take the form of spiral shocks, resulting in streaming motions in the gas, and in inflow comparable to the accretion rates needed to power local Active Galactic Nuclei. Recently streaming motions of amplitude expected from the models have been observed in nuclear spirals, confirming the role of nuclear spirals in feeding of the central massive black holes.

Witold Maciejewski

2006-11-08T23:59:59.000Z

237

Energy in history  

SciTech Connect (OSTI)

This book presents the papers given at a symposium on the development of energy technologies in Czechoslovakia during the Industrial Revolution. Topics considered at the symposium included steam drive in the epoch of the Industrial Revolution, the energy crisis in the milling industry of late feudalism, the energy base of the food industry during the industrial and scientific revolution, power engineering in agriculture, and new energy in the transportation sector during the automobile revolution.

Purs, J.

1984-01-01T23:59:59.000Z

238

Homotopy in statistical physics  

E-Print Network [OSTI]

In condensed matter physics and related areas, topological defects play important roles in phase transitions and critical phenomena. Homotopy theory facilitates the classification of such topological defects. After a pedagogic introduction to the mathematical methods involved in topology and homotopy theory, the role of the latter in a number of mainly low-dimensional statistical-mechanical systems is outlined. Some recent activities in this area are reviewed and some possible future directions are discussed.

Ralph Kenna

2006-04-12T23:59:59.000Z

239

Experiences in Applying Formal Verification in Robotics  

E-Print Network [OSTI]

and certifying a safety function for autonomous vehicles and robots. We out- line the algorithm which such as the area covered by a braking robot in our case, play a central role. This leads to an increase

Lth, Christoph - Deutschen Forschungszentrum fr Knstliche Intelligenz & Fachbereich 3

240

Dust Measurements in Tokamaks  

SciTech Connect (OSTI)

Dust production and accumulation impose safety and operational concerns for ITER. Diagnostics to monitor dust levels in the plasma as well as in-vessel dust inventory are currently being tested in a few tokamaks. Dust accumulation in ITER is likely to occur in hidden areas, e.g. between tiles and under divertor baffles. A novel electrostatic dust detector for monitoring dust in these regions has been developed and tested at PPPL. In DIII-D tokamak dust diagnostics include Mie scattering from Nd:YAG lasers, visible imaging, and spectroscopy. Laser scattering resolves size of particles between 0.16-1.6 {micro}m in diameter; the total dust content in the edge plasmas and trends in the dust production rates within this size range have been established. Individual dust particles are observed by visible imaging using fast-framing cameras, detecting dust particles of a few microns in diameter and larger. Dust velocities and trajectories can be determined in 2D with a single camera or 3D using multiple cameras, but determination of particle size is problematic. In order to calibrate diagnostics and benchmark dust dynamics modeling, pre-characterized carbon dust has been injected into the lower divertor of DIII-D. Injected dust is seen by cameras, and spectroscopic diagnostics observe an increase of carbon atomic, C2 dimer, and thermal continuum emissions from the injected dust. The latter observation can be used in the design of novel dust survey diagnostics.

Rudakov, D; Yu, J; Boedo, J; Hollmann, E; Krasheninnikov, S; Moyer, R; Muller, S; Yu, A; Rosenberg, M; Smirnov, R; West, W; Boivin, R; Bray, B; Brooks, N; Hyatt, A; Wong, C; Fenstermacher, M; Groth, M; Lasnier, C; McLean, A; Stangeby, P; Ratynskaia, S; Roquemore, A; Skinner, C; Solomon, W M

2008-04-23T23:59:59.000Z

Note: This page contains sample records for the topic "antiknock in dex" 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

Nuclear Masses in Astrophysics  

E-Print Network [OSTI]

Among all nuclear ground-state properties, atomic masses are highly specific for each particular combination of N and Z and the data obtained apply to a variety of physics topics. One of the most crucial questions to be addressed in mass spectrometry of unstable radionuclides is the one of understanding the processes of element formation in the Universe. To this end, accurate atomic mass values of a large number of exotic nuclei participating in nucleosynthesis are among the key input data in large-scale reaction network calculations. In this paper, a review on the latest achievements in mass spectrometry for nuclear astrophysics is given.

Christine Weber; Klaus Blaum; Hendrik Schatz

2008-12-09T23:59:59.000Z

242

Alfalfa Production in Texas.  

E-Print Network [OSTI]

DIGEST Alfalfa was first grown in Texas in 1892. It has gradually increased in economic importance among the forage legumes until it now is the most important hay crop in the State. The most im- portant varieties include Southwest Common, Bar...- stow Common, Buffalo, Ranger and Hairy Peru- vian. The variety Lahontan may be used widely in the next few years because of its high degree of resistance to the spotted alfalfa aphid. Alfalfa is one of the most exacting forage crops in its...

Staten, Raymond D.

1957-01-01T23:59:59.000Z

243

In other news  

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 withconfinementEtching.348 270 300Aptamers and GraphenePhaseNewsaInInInInInIn

244

Energy in density gradient  

E-Print Network [OSTI]

Inhomogeneous plasmas and fluids contain energy stored in inhomogeneity and they naturally tend to relax into lower energy states by developing instabilities or by diffusion. But the actual amount of energy in such inhomogeneities has remained unknown. In the present work the amount of energy stored in a density gradient is calculated for several specific density profiles in a cylindric configuration. This is of practical importance for drift wave instability in various plasmas, and in particular in its application in models dealing with the heating of solar corona because the instability is accompanied with stochastic heating, so the energy contained in inhomogeneity is effectively transformed into heat. It is shown that even for a rather moderate increase of the density at the axis in magnetic structures in the corona by a factor 1.5 or 3, the amount of excess energy per unit volume stored in such a density gradient becomes several orders of magnitude greater than the amount of total energy losses per unit ...

Vranjes, J

2015-01-01T23:59:59.000Z

245

Wind Power in Alaska  

Broader source: Energy.gov [DOE]

In the past few years wind power has become more and more prevalent across Alaska, with big turbines sprouting up in all parts of the state. Sponsored by the Renewable Energy Alaska Project, event...

246

Holes in Spectral Lines  

E-Print Network [OSTI]

The decay of an atom in the presence of a static perturbation is investigated. The perturbation couples a decaying state with a nondecaying state. A "hole" appears in the emission line at a frequency equal to the frequency ...

Fontana, Peter R.; Srivastava, Rajendra P.

1973-06-01T23:59:59.000Z

247

Olefin Autoxidation in Flow  

E-Print Network [OSTI]

Handling hazardous multiphase reactions in flow brings not only safety advantages but also significantly improved performance, due to better mass transfer characteristics. In this paper, we present a continuous microreactor ...

Neuenschwander, Ulrich

248

Advertising in computer games  

E-Print Network [OSTI]

This paper suggests advertisers should experiment with in-game advertising to gain skills that could become vital in the near future. It compiles, arranges and analyzes the existing body of academic and industry knowledge ...

Vedrashko, Ilya

2006-01-01T23:59:59.000Z

249

Interface Magnetism in Multiferroics  

E-Print Network [OSTI]

1.2.1 Magnetism . . . . . . . . . . . . . . . . . . . 1.2.2domain walls . . . . . 3 Magnetism of domain walls in BiFeOof electrical control of magnetism in mixed phase BiFeO 3

He, Qing

2011-01-01T23:59:59.000Z

250

Safety in Buildings  

E-Print Network [OSTI]

Building codes are essentially sets of safety regulations in respect of structure, fire, and health. They were originally developed in response to frequently demonstrated hazards of structural collapse, catastrophic fires, and the spread of disease...

Hutcheon, N. B.

251

Three essays in macroeconomics  

E-Print Network [OSTI]

This thesis is a collection of three essays on international trade and economic growth. Chapter 1 analyzes the dynamic gains from trade in a Hecksher-Ohlin economy with endogenous factor accumulation. In a framework where ...

Auer, Raphael Anton Maximilian Peter Gabriel

2006-01-01T23:59:59.000Z

252

Graduate Program in Telecommunications  

E-Print Network [OSTI]

Communications analyst Network administrator Systems engineer Security officer www.ischool.pitt.edu MartinGraduate Program in Telecommunications and Networking #12;Why Telecommunications and Networking sophisticated network infrastructures. These network infrastructures bring functional challenges in network

Jiang, Huiqiang

253

Defektlinien in Isingsystemen Diplomarbeit  

E-Print Network [OSTI]

Systems. Der Faktor 1 2 in (1.1) tritt auf, da man in der Doppelsumme jedes Spinpaar doppelt zählt. Im der Thermodynamik bekannt ist, tritt im thermischen Gleichgewicht bei einer Temperatur T eine

Usadel, K. D.

254

Essays in financial economics  

E-Print Network [OSTI]

This thesis consists of three empirical essays in financial economics, examining the consequences of imperfect financial markets for households, small business and house prices. In the first chapter (co-authored with Meta ...

Severino Daz, Felipe

2014-01-01T23:59:59.000Z

255

Three essays in macroeconomics  

E-Print Network [OSTI]

Chapter 1 analyzes the theoretical and quantitative implications of optimal fiscal policy in a business cycle model with incomplete markets. I first consider the problem of a government facing expenditure shocks in an ...

Farhi, Emmanuel

2006-01-01T23:59:59.000Z

256

Essays in capital markets  

E-Print Network [OSTI]

In the first chapter, I provide evidence that investment-specific technological change is a source of systematic risk. In contrast to neutral productivity shocks, the economy needs to invest to realize the benefits of ...

Papanikolaou, Dimitris, Ph. D. Massachusetts Institute of Technology

2007-01-01T23:59:59.000Z

257

In situ measurement system  

DOE Patents [OSTI]

A multipurpose in situ underground measurement system comprising a plurality of long electrical resistance elements in the form of rigid reinforcing bars, each having an open loop hairpin configuration of shorter length than the other resistance elements. The resistance elements are arranged in pairs in a unitized structure, and grouted in place in the underground volume. Measurement means are provided for obtaining for each pair the electrical resistance of each element and the difference in electrical resistance of the paired elements, which difference values may be used in analytical methods involving resistance as a function of temperature. A scanner means sequentially connects the resistance-measuring apparatus to each individual pair of elements. A source of heating current is also selectively connectable for heating the elements to an initial predetermined temperature prior to electrical resistance measurements when used as an anemometer.

Lord, D.E.

1980-11-24T23:59:59.000Z

258

Specific light in sculpture  

E-Print Network [OSTI]

Specific light is defined as light from artificial or altered natural sources. The use and manipulation of light in three dimensional sculptural work is discussed in an historic and contemporary context. The author's work ...

Powell, John William

1989-01-01T23:59:59.000Z

259

HYDROGEN IN GERMANIUM  

E-Print Network [OSTI]

LBL-7996 of the donors phosphorous and D in pure germaniumspectra of the donors phosphorous and D in crys­ tals grownof the donor D and of phosphorous at three different values

Haller, E.E.

2011-01-01T23:59:59.000Z

260

Entanglement in Classical Optics  

E-Print Network [OSTI]

The emerging field of entanglement or nonseparability in classical optics is reviewed, and its similarities with and differences from quantum entanglement clearly pointed out through a recapitulation of Hilbert spaces in general, the special restrictions on Hilbert spaces imposed in quantum mechanics and the role of Hilbert spaces in classical polarization optics. The production of Bell-like states in classical polarization optics is discussed, and new theorems are proved to discriminate between separable and nonseparable states in classical wave optics where no discreteness is involved. The influence of the Pancharatnam phase on a classical Bell-like state is deived. Finally, to what extent classical polarization optics can be used to simulate quantum information processing tasks is also discussed. This should be of great practical importance because coherence and entanglement are robust in classical optics but not in quantum systems.

Partha Ghose; Anirban Mukherjee

2013-09-12T23:59:59.000Z

Note: This page contains sample records for the topic "antiknock in dex" 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

Essays in financial econometrics  

E-Print Network [OSTI]

Chapter 1 is the product of joint work with Ferhat Akbas and it provides a behavioral explanation for monthly negative serial correlation in stock returns. For the first time in the literature, this work reports that only ...

Kocatulum, Emre

2008-01-01T23:59:59.000Z

262

Derivative actions in China  

E-Print Network [OSTI]

The enactment of derivative action was expected to be actively used by shareholders to protect their interests. In fact, it turned out that this reform effort seemed futile as the right to engage in such actions was ...

Lin, Shaowei

2014-07-02T23:59:59.000Z

263

South Asians in Boston  

E-Print Network [OSTI]

Boston has a rich and diverse history of immigrants. Right from the arrival of the Puritans in 1628-30 who established the earliest immigrant settlements in Boston, this region has attracted immigrants from different parts ...

Masurkar, Alpita

2012-01-01T23:59:59.000Z

264

Endocytosis in filamentous fungi  

E-Print Network [OSTI]

Endocytosis is little understood in filamentous fungi. For some time it has been controversial as to whether endocytosis occurs in filamentous fungi. A comparative genomics analysis between Saccharomyces cerevisiae and ...

Kalkman, Edward R I C

2007-01-01T23:59:59.000Z

265

Systems building in architecture  

E-Print Network [OSTI]

This work is an inquiry into the interventions of the systems design in the whole building process. At the beginning, three approaches which represent different points of view of interventions in production and use are ...

Tzannetakis, Charilaos Panayotis

1983-01-01T23:59:59.000Z

266

Protest in Ethiopia  

E-Print Network [OSTI]

thesis on "Christianity in Ethiopia". He has also written awith Local Religions in Ethiopia. GROUP AND A SINGLE by D.entrust the destiny of Ethiopia? Footnotes: Quoted i n R.

Nicolas, Gildas

1972-01-01T23:59:59.000Z

267

Innovations in petrochemical crackers  

SciTech Connect (OSTI)

A comprehensive review will be given on the latest innovations in petrochemical cracker technologies. These improvements can result in significant costs reduction for various feedstocks. Several examples will be illustrated.

Chambers, L. [Stone & Webster, Houston, TX (United States)

1996-10-01T23:59:59.000Z

268

Homelessness in California  

E-Print Network [OSTI]

in-Publication Data Quigley, John M. Homelessness inMassachusetts, 1996. Quigley, John M. , A Decent Home:1, 2000, pp. 5388. Quigley, John M. and Steven Raphael,

Quigley, John M.; Raphael, Steven; Smolensky, Eugene

2001-01-01T23:59:59.000Z

269

Synchronization in complex networks  

SciTech Connect (OSTI)

Synchronization processes in populations of locally interacting elements are in the focus of intense research in physical, biological, chemical, technological and social systems. The many efforts devoted to understand synchronization phenomena in natural systems take now advantage of the recent theory of complex networks. In this review, we report the advances in the comprehension of synchronization phenomena when oscillating elements are constrained to interact in a complex network topology. We also overview the new emergent features coming out from the interplay between the structure and the function of the underlying pattern of connections. Extensive numerical work as well as analytical approaches to the problem are presented. Finally, we review several applications of synchronization in complex networks to different disciplines: biological systems and neuroscience, engineering and computer science, and economy and social sciences.

Arenas, A.; Diaz-Guilera, A.; Moreno, Y.; Zhou, C.; Kurths, J.

2007-12-12T23:59:59.000Z

270

Essays in financial economics  

E-Print Network [OSTI]

This thesis consists of three essays in financial economics. Chapter 1 is entitled "Inside Debt." Existing theories advocate the use of cash and equity in executive compensation. However, recent empirical studies have ...

Edmans, Alex

2007-01-01T23:59:59.000Z

271

Progress in Superconducting Metamaterials  

E-Print Network [OSTI]

We review progress in the development and applications of superconducting metamaterials. The review is organized in terms of several distinct advantages and unique properties brought to the metamaterials field by superconductivity. These include the low-loss nature of the meta-atoms, their compact structure, their extraordinary degree of nonlinearity and tunability, magnetic flux quantization and the Josephson effect, quantum effects in which photons interact with quantized energy levels in the meta-atom, as well as strong diamagnetism.

Philipp Jung; Alexey V. Ustinov; Steven M. Anlage

2014-03-25T23:59:59.000Z

272

Magnetic susceptibility in QCD  

E-Print Network [OSTI]

Magnetic susceptibility in the deconfined phase of QCD is calculated in a closed form using a recent general expression for the quark gas pressure in magnetic field. Quark selfenergies are entering the result via Polyakov line factors and ensure the total paramagnetic effect, increasing with temperature. A generalized form of magnetic susceptibility in nonzero magnetic field suitable for experimental and lattice measurements is derived, showing a good agreement with available lattice data.

V. D. Orlovsky; Yu. A. Simonov

2014-05-12T23:59:59.000Z

273

Electroluminescence in photovoltaic cell  

E-Print Network [OSTI]

Here we propose two methods to get electroluminescence images from photovoltaic cells in a school or home lab.

Petraglia, Antonio; 10.1088/0031-9120/46/5/F01

2011-01-01T23:59:59.000Z

274

Innovation Concepts in Healthcare  

SciTech Connect (OSTI)

AbstractDemographic change and advances in medical science pose increased challenges to healthcare systems globally: The economic basis is aging and thus health is becoming more and more a productivity factor. At the same time, with todays new communication possibilities the demand and expectations of effective medical treatment have been increased. This presentation will illustrate the need for the industrialization of healthcare in order to achieve highest results at limited budgets. Thereby, industrialization is not meaning the medical treatment based on the assembly line approach. Rather it is to recognize the cost of medical care as an investment with respective expectations on the return of the investment. Innovations in imaging and pharmaceutical products as well as in processes - that lead to similar medical results, but with lower efforts - are keys in such scenarios.BiographyProf. Dr. Hermann Requardt, 54, is a member of the Managing Board of Siemens AG and Chief Executive Officer of the Healthcare Sector. In addition he is the CTO of Siemens AG and Head of Corporate Technology, the central research department at Siemens.After completing his studies in physics and philosophy at the Darmstadt University of Technology and Johann Wolfgang Goethe University in Frankfurt and receiving a doctorate in biophysics, he worked at the Institute of Aerospace Medicine at the German Aerospace Center.In 1984 he joined the Medical Technology Group of Siemens AG, where he was responsible for projects in the Magnetic Resonance (MR) division. He was appointed head of the division in 1995. From 2001 to 2006, as a member of the Executive Management of the Medical Solutions Group, he was responsible for several areas, including technological development.In 2006 he became a Member of the Siemens Managing Board and head of Corporate Technology. He was additionally appointed as the Sector Healthcare CEO in 2008.Since 2006 he is an honorary professor in physics of the Johann Wolfgang Goethe University in Frankfurt.

None

2011-01-06T23:59:59.000Z

275

Cognitive deficits in depression  

E-Print Network [OSTI]

COGNITIVE DEFICITS IN DEPRESSION A Thesis MARY ELLEN HAINES Submitted to the Office of Graduate Studies of Texas ASM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1993 Major Subject...: Psychology COGNITIVE DEFICITS IN DEPRESSION A Thesis by MARY ELLEN HAINES Submitted to Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved as to style and content by argaret P. orris Chair...

Haines, Mary Ellen

2012-06-07T23:59:59.000Z

276

Motion in Quantum Gravity  

E-Print Network [OSTI]

We tackle the question of motion in Quantum Gravity: what does motion mean at the Planck scale? Although we are still far from a complete answer we consider here a toy model in which the problem can be formulated and resolved precisely. The setting of the toy model is three dimensional Euclidean gravity. Before studying the model in detail, we argue that Loop Quantum Gravity may provide a very useful approach when discussing the question of motion in Quantum Gravity.

Karim Noui

2010-03-31T23:59:59.000Z

277

Kumar Krishna, in appreciation  

E-Print Network [OSTI]

Kumar Krishna, in appreciation 1 Kumar Krishna, in appreciation Michael S. Engel1,2, David A. Grimaldi2 1 Division of Entomology, Natural History Museum, and Department of Ecology & Evolutionary Biology, 1501 Crestline Drive Suite 140, University... November 2011 | Accepted 8 November 2011 | Published 21 November 2011 Citation: Engel MS, Grimaldi DS (2011) Kumar Krishna, in appreciation. In: Engel MS (Ed) Contributions Celebrating Kumar Krishna. ZooKeys 148: 113. doi: 10.3897/zookeys.148...

Engel, Michael S.; Grimaldi, David

2011-11-21T23:59:59.000Z

278

Early enlightenment in Istanbul  

E-Print Network [OSTI]

had emerged in medieval Konya, and ad- vocated thatearly age, mer moved to Konya, perhaps the most important

Kck, Bekir Harun

2012-01-01T23:59:59.000Z

279

Crying in the Wilderness  

E-Print Network [OSTI]

Crying in the Wilderness Bennett G. Galef, Jr. McMastershould be addressed to Bennett G. Galef, Jr. Department of

Galef, Bennett G. Jr.

2007-01-01T23:59:59.000Z

280

Embodiment in social psychology  

E-Print Network [OSTI]

, highlighting some promising future directions. 1. The use of embodiment in social psychology Although embodied theories started gaining steam in the 1990s (Barsalou, 1999; Gibbs, 2006), approaches related to embodiment have a long tradition in social psychol... 1180. Higgins, E. T. (1996). Knowledge activation: Accessibility, applicability, and salience. In E. T. Higgins & A. W. Kruglanski (Eds.), Social psychology: Handbook of basic principles (pp. 133168). New York: Guilford Press. Izjerman, H., & Semin, G. (2010...

Meier, Brian P.; Schnall, Simone; Schwarz, Norbert; Bargh, John, A.

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "antiknock in dex" 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

Embodiment in social psychology  

E-Print Network [OSTI]

directions. The Use of Embodiment in Social Psychology Although embodied theories started gaining steam in the 1990s (Barsalou, 1999; Gibbs, 2006), approaches related to embodiment have a long tradition in social psychology. From addressing how... 13 Higgins, E. T. (1996). Knowledge activation: Accessibility, applicability, and salience. In E. T. Higgins & A. W. Kruglanski (Eds.), Social psychology: Handbook of basic principles (pp. 133-168). New York: Guilford Press. Izjerman, H., & Semin...

Meier, Brian P.; Schnall, Simone; Schwarz, Norbert; Bargh, John, A.

2012-01-01T23:59:59.000Z

282

In situ groundwater bioremediation  

E-Print Network [OSTI]

J. W. Costerton. 1992. Enhanced oil-recovery - 3-dimensionalused for enhanced oil recovery in oil reservoirs (Cusack et.

Hazen, Terry C.

2010-01-01T23:59:59.000Z

283

Innovation Concepts in Healthcare  

ScienceCinema (OSTI)

AbstractDemographic change and advances in medical science pose increased challenges to healthcare systems globally: The economic basis is aging and thus health is becoming more and more a productivity factor. At the same time, with today?s new communication possibilities the demand and expectations of effective medical treatment have been increased. This presentation will illustrate the need for the ?industrialization? of healthcare in order to achieve highest results at limited budgets. Thereby, industrialization is not meaning the medical treatment based on the assembly line approach. Rather it is to recognize the cost of medical care as an investment with respective expectations on the return of the investment. Innovations in imaging and pharmaceutical products as well as in processes - that lead to similar medical results, but with lower efforts - are keys in such scenarios.BiographyProf. Dr. Hermann Requardt, 54, is a member of the Managing Board of Siemens AG and Chief Executive Officer of the Healthcare Sector. In addition he is the CTO of Siemens AG and Head of Corporate Technology, the central research department at Siemens.After completing his studies in physics and philosophy at the Darmstadt University of Technology and Johann Wolfgang Goethe University in Frankfurt and receiving a doctorate in biophysics, he worked at the Institute of Aerospace Medicine at the German Aerospace Center.In 1984 he joined the Medical Technology Group of Siemens AG, where he was responsible for projects in the Magnetic Resonance (MR) division. He was appointed head of the division in 1995. From 2001 to 2006, as a member of the Executive Management of the Medical Solutions Group, he was responsible for several areas, including technological development.In 2006 he became a Member of the Siemens? Managing Board and head of Corporate Technology. He was additionally appointed as the Sector Healthcare CEO in 2008.Since 2006 he is an honorary professor in physics of the Johann Wolfgang Goethe University in Frankfurt.

None

2011-04-25T23:59:59.000Z

284

Optimization in Networks  

E-Print Network [OSTI]

The recent surge in the network modeling of complex systems has set the stage for a new era in the study of fundamental and applied aspects of optimization in collective behavior. This Focus Issue presents an extended view of the state of the art in this field and includes articles from a large variety of domains where optimization manifests itself, including physical, biological, social, and technological networked systems.

Adilson E. Motter; Zoltan Toroczkai

2007-07-07T23:59:59.000Z

285

Partnership in Computational Science  

SciTech Connect (OSTI)

This is the final report for the "Partnership in Computational Science" (PICS) award in an amount of $500,000 for the period January 1, 1993 through December 31, 1993. A copy of the proposal with its budget is attached as Appendix A. This report first describes the consequent significance of the DOE award in building infrastructure of high performance computing in the Southeast and then describes the work accomplished under this grant and a list of publications resulting from it.

Huray, Paul G.

1999-02-24T23:59:59.000Z

286

In this document: Freshmanadmissiondecisionoverview  

E-Print Network [OSTI]

In this document: Freshmanadmissiondecisionoverview Academicprofileoffall2012 and Human Development Liberal Arts Management (Carlson School of) Science and Engineering #12;Frequently

Blanchette, Robert A.

287

In this document: Freshmanadmissiondecisionoverview  

E-Print Network [OSTI]

In this document: Freshmanadmissiondecisionoverview Academicprofileoffall2012, Agricultural and Natural Resource Sciences Education and Human Development Liberal Arts Management (Carlson

Blanchette, Robert A.

288

in Economics and Finance  

E-Print Network [OSTI]

Master's in Economics and Finance ­ #12;2 3 "A research-centred institution with a personal REASONS TO STUDY The Master's in Economics and Finance programme targets students wishing to obtain a comprehensive and rigorous education in Economics and Finance. It emphasizes the complementary nature

van der Torre, Leon

289

Hispanic Theatre in Kansas  

E-Print Network [OSTI]

96 LATIN AMERICAN THEATRE REVIEW Hispanic Theatre in Kansas The Fanlights (Los soles truncos), by the late Rene Marqus, was performed in English translation at the University of Kansas, in Lawrence, April 10-12 and 17-21, 1979. The play...

1979-04-01T23:59:59.000Z

290

Correspondences DDT resistance in  

E-Print Network [OSTI]

Magazine R587 Correspondences DDT resistance in flies carries no cost Caroline McCart1, Angus to carry a cost in the absence of pesticide and consequently not to spread to fixation [1,2]. However, DDT resistance in Drosophila melanogaster (DDT-R) is approaching fixation globally, long after withdrawl of DDT

Buckling, Angus

291

programs in climate change  

E-Print Network [OSTI]

existing programs in climate change science and infrastructure. The Laboratory has a 15- year history in climate change science. The Climate, Ocean and Sea Ice Modeling (COSIM) project develops and maintains advanced numerical models of the ocean, sea ice, and ice sheets for use in global climate change

292

Muon capture in hydrogen  

E-Print Network [OSTI]

Theoretical difficulties in reconciling the measured rates for ordinary and radiative muon capture are discussed, based on heavy-baryon chiral perturbation theory. We also examine ambiguity in our analysis due to the formation of p$\\mu$p molecules in the liquid hydrogen target.

S. Ando; F. Myhrer; K. Kubodera

2001-10-30T23:59:59.000Z

293

Aging in community  

E-Print Network [OSTI]

Baby Boomers are on the brink of retirement. According to U.S. Census Bureau projections, the number of people aged 65 and over will more than double in the coming decades, growing from 35 million in 2000 to 72 million in ...

Fay, Justin (Justin Thomas)

2008-01-01T23:59:59.000Z

294

HELPING STUDENTS IN DISTRESS  

E-Print Network [OSTI]

HELPING STUDENTS IN DISTRESS A FACULTY & STAFF GUIDE FOR ASSISTING STUDENTS IN NEED UNIVERSITY high rates of recovery if appropriate help is received in time. Unfortunately, many students fail to get the help they need for any number of reasons, including lack of knowledge about the early signs

Hill, Wendell T.

295

The cartel in retreat  

E-Print Network [OSTI]

In 1981, the price of oil was $34 in current dollars ($50 at 1992 price levels). The consensus was that it would keep rising toward the cost of synthetic crude oil or some such long-run ceiling. In fact, the cartel had ...

Adelman, Morris Albert

1993-01-01T23:59:59.000Z

296

Extinction curves in AGN  

E-Print Network [OSTI]

The presence of the dust in the circumnuclear region strongly affects our view of the nucleus itself. The effect is strong in type 2 objects but weaker effect is likely to be present in type 1 objects as well. In these objects a correction to the observed optical/UV spectrum must be done in order to recover the intrinsic spectrum of a nucleus. The approach based on the extinction curve is convenient for that purpose so significant effort has been recently done in order to determine the extinction curve for the circumnuclear material. It seems clear that the circumnuclear dust is different from the average properties of the dust in the Interstellar Medium in our galaxy: the well known 2175 A feature is weak or absent in AGN nuclear dust, and the extinction curve at shorter wavelength does not seem to be rising as steeply. The circumnuclear dust is therefore more similar to SMC dust, or more likely, to the dust in very dense molecular clouds in our Galaxy. However, the exact shape of the extinction curve in the far UV is still a matter of debate, and various effects are difficult to disentangle.

B. Czerny

2006-12-16T23:59:59.000Z

297

discoveries in drugs and  

E-Print Network [OSTI]

Engineering Training Program (PETP) was initiated in 1995 and was the first in the nation to formally combineD, is a faculty member and director of the Pharmaceutical Engineering Training Program (PETP) in the Department the country funded by the National Science Foundation. PETP is a joint venture of the De- partment of Chemical

Glasser, Benjamin J.

298

Stability and Complexity in  

E-Print Network [OSTI]

and complexity of a commu- nity of interacting plants and animals, following the food web as a clue. Contrary in power. Stability and Complexity in Model Ecosystems played a key role in introducing nonlinear thinking, and current threats to biodiversity have made questions about the role of ecosystem complexity

Landweber, Laura

299

Progress and Accomplishments in  

E-Print Network [OSTI]

development of a solid-oxide fuel cell for micro-combined heat and power applications with an almost 25% increase in system power density, which has enabled a more than 30% reduction in stack volume and a 15 Demonstrated more than 2,500 - hour (75,000 miles) durability of fuel cell systems in vehicles operating under

300

Homelessness in California  

E-Print Network [OSTI]

Homelessness in California · · · John M. Quigley Steven Raphael Eugene Smolensky with Erin Mansur-in-Publication Data Quigley, John M. Homelessness in California / John M. Quigley, Steven Raphael, Eugene Smolensky. p. The authors of the present volume--John Quigley, Stephen Raphael, and Eugene Smolensky, all from the Goldman

Sekhon, Jasjeet S.

Note: This page contains sample records for the topic "antiknock in dex" 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

PACE in Texas 101  

E-Print Network [OSTI]

to be available in many Texas regions in 2015. What is PACE and is there PACE in Texas? ESL-KT-14-11-35 CATEE 2014: Clean Air Through Efficiency Conference, Dallas, Texas Nov. 18-20 PACE tackles key barriers Source: Institute for Building Efficiency ESL-KT-14...

Stone,R.

2014-01-01T23:59:59.000Z

302

Gabriel Ulici Laurea magistrale in ingegneria in-  

E-Print Network [OSTI]

Personali Nome Cognome Gabriel Ulici Data di nascita 23 Settembre 1987 Luogo di nascita Satu Mare, Romania- versità Rumeno­Americana, Bucarest, Romania, ISCED 5. Set 2002­Lug 2006 Diploma di Scuola Superiore in Informatica, Collegio Nazionale "Ioan Slavici", Satu Mare, Romania, ISCED 3. Interessi di Ricerca

Di Pillo, Gianni

303

Women in Physics in the United States  

E-Print Network [OSTI]

Friendly Edge (including articles by Prof. Mary Ann Mason) ucfamilyedge.berkeley.edu/ The Gender Equity Project (including articles by Prof. Virginia Valian): www.hunter.cuny.edu/genderequity/ Women Don't Ask: ... women's representation and advancement in academic STEM positions are affected by many external factors

Ito, Atsushi

304

Recent Trends in Land Tenure in Texas.  

E-Print Network [OSTI]

and a live- stock program was instituted. Long term cash leases presented problems during this period of fluctuating commodity prices, One- year farm rental agreements, on the other hand, failed to provide the necessary inducements for the long... ............................................................................. 24 Effect of changes in land tenure on community institutions .................... 25 Landlord-tenant relations ........................................................................................ 26 Farm rental agreements...

Motheral, Joe

1944-01-01T23:59:59.000Z

305

Shared Space vs. In-Unit Upgrades in Multifamily Buildings |...  

Energy Savers [EERE]

Shared Space vs. In-Unit Upgrades in Multifamily Buildings Shared Space vs. In-Unit Upgrades in Multifamily Buildings Better Buildings Neighborhood Program Multifamily Peer...

306

Singing in the Shower to Shaking in Your Boots  

E-Print Network [OSTI]

Singing in the Shower to Shaking in Your Boots: The science in the Shower to Shaking in Your Boots: The science of emotion Speaking about

Chou, James

307

PACCAR CRADA: Experimental Investigation in Coolant Boiling in...  

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

PACCAR CRADA: Experimental Investigation in Coolant Boiling in a Half-Heated Circular Tube PACCAR CRADA: Experimental Investigation in Coolant Boiling in a Half-Heated Circular...

308

Recent Trends in Car Usage in Advanced Economies - Slower Growth...  

Open Energy Info (EERE)

Trends in Car Usage in Advanced Economies - Slower Growth Ahead? Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Recent Trends in Car Usage in Advanced Economies -...

309

Gauging Improvements in Urban Building Energy Policy in India  

E-Print Network [OSTI]

Urban Building Energy Policy in India Christopher WilliamsUrban Building Energy Policy in India Christopher Williamsefficiency policies and programs in India are in an active

Williams, Christopher

2013-01-01T23:59:59.000Z

310

CRYSTALLIZATION IN MULTICOMPONENT GLASSES  

SciTech Connect (OSTI)

In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.

KRUGER AA; HRMA PR

2009-10-08T23:59:59.000Z

311

Clustering in nuclear environment  

E-Print Network [OSTI]

The properties of few-body clusters (mass number $A \\le 4$) are modified if they are immersed in a nuclear medium. In particular, Pauli blocking that reflects the antisymmetrization of the many-body wave function is responsible for the medium modification of light clusters and the dissolution with increasing density. A more consistent description is given with takes also the contribution of correlations in the continuum into account. The relation between cluster formation in warm dense matter and in nuclear structure is discussed.

G. Rpke

2014-08-12T23:59:59.000Z

312

Ferromagnetism in Oxide Semiconductors  

SciTech Connect (OSTI)

In order to become a practical technology, semiconductor spintronics requires the discovery and utilization of ferromagnetic semiconductors which exhibit spin polarization in the majority carrier band at and above room temperature. Intrinsic remanent magnetization would allow spin polarized currents to be propagated in such materials without the need for a continuous magnetic field. However, the discovery and understanding of such materials is proving to be a grand challenge in solid-state science. Indeed, one of the 125 critical unanswered scientific questions recently posed in Science magazine asks, Is it possible to create magnetic semiconductors that work at room temperature?

Chambers, Scott A.; Droubay, Timothy C.; Wang, Chong M.; Rosso, Kevin M.; Heald, Steve M.; Schwartz, S. A.; Kittilstved, Kevin R.; Gamelin, Daniel R.

2006-11-01T23:59:59.000Z

313

Barley Production in Texas.  

E-Print Network [OSTI]

inclusive, an average of 14 6,O 0 0 acres of barley was planted, producing an average annual production of 2,445,000 bushels. The acreage and pro- duction fluctuate widely, being influenced by spring moisture conditions in west Texas and by winterkilling... the winter months, than on un- protected land. In west Texas it also may aid in reducing soil blowing. Barley may be used for hay or green manure crops, and in other sec- tions is used extensively in the brewing industry. At present very little barley...

Dunkle, P. B. (Paul Burtch); Atkins, Irvin Milburn

1941-01-01T23:59:59.000Z

314

In other news  

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 withconfinementEtching.348 270 300Aptamers and GraphenePhaseNewsaInInInInIn

315

In other news  

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 withconfinementEtching.348 270 300Aptamers andIn other news CommunityInInInIn

316

Research in particle theory  

SciTech Connect (OSTI)

In the test particle approximation, the scattering amplitude for two-particle scattering in (2+1)-dimensional Chern-Simons-Witten gravity and supergravity was computed and compared to the corresponding metric solutions. The formalism was then extended to the exact gauge theoretic treatment of the two-particle scattering problem and compared to 't Hooft's results from the metric approach. We have studied dynamical symmetry breaking in 2+1 dimensional field theories. We have analyzed strong Extended Technicolor (ETC) models where the ETC coupling is close to a critical value. There are effective scalar fields in each of the theories. We have worked our how such scalar particles can be produced and how they decay. The {phi}{sup 4} field theory was investigated in the Schrodinger representation. The critical behavior was extracted in an arbitrary number of dimensions in second order of a systematic truncation approximation. The correlation exponent agrees with known values within a few percent.

Mansouri, F.; Suranyi, P; Wijewardhana, L.C.R.

1991-10-01T23:59:59.000Z

317

Geothermal development in Australia  

SciTech Connect (OSTI)

In Australia, natural hot springs and hot artesian bores have been developed for recreational and therapeutic purposes. A district heating system at Portland, in the Otway Basin of western Victoria, has provided uninterrupted service for 12 Sears without significant problems, is servicing a building area of 18 990 m{sup 2}, and has prospects of expansion to manufacturing uses. A geothermal well has provided hot water for paper manufacture at Traralgon, in the Gippsland Basin of eastern Victoria. Power production from hot water aquifers was tested at Mulka in South Australia, and is undergoing a four-year production trial at Birdsville in Queensland. An important Hot Dry Rock resource has been confirmed in the Cooper Basin. It has been proposed to build an HDR experimental facility to test power production from deep conductive resources in the Sydney Basin near Muswellbrook.

Burns, K.L. [Los Alamos National Lab., NM (United States); Creelman, R.A. [Creelman (R.A.) and Associates, Sydney, NSW (Australia); Buckingham, N.W. [Glenelg Shire Council, Portland, VIC (Australia); Harrington, H.J. [Australian National Univ., Canberra, ACT (Australia)]|[Sydney Univ., NSW (Australia)

1995-03-01T23:59:59.000Z

318

Photoneutron reactions in astrophysics  

SciTech Connect (OSTI)

Among key problems in nuclear astrophysics, that of obtaining deeper insight into the mechanism of synthesis of chemical elements is of paramount importance. The majority of heavy elements existing in nature are produced in stars via radiative neutron capture in so-called s- and r processes, which are, respectively, slow and fast, in relation to competing ?{sup ?}-decay processes. At the same time, we know 35 neutron-deficient so-called bypassed p-nuclei that lie between {sup 74}Se and {sup 196}Hg and which cannot originate from the aforementioned s- and r-processes. Their production is possible in (?, n), (?, p), or (?, ?) photonuclear reactions. In view of this, data on photoneutron reactions play an important role in predicting and describing processes leading to the production of p-nuclei. Interest in determining cross sections for photoneutron reactions in the threshold energy region, which is of particular importance for astrophysics, has grown substantially in recent years. The use of modern sources of quasimonoenergetic photons obtained in processes of inverse Compton laser-radiation scattering on relativistic electronsmakes it possible to reveal rather interesting special features of respective cross sections, manifestations of pygmy E1 and M1 resonances, or the production of nuclei in isomeric states, on one hand, and to revisit the problem of systematic discrepancies between data on reaction cross sections from experiments of different types, on the other hand. Data obtained on the basis of our new experimental-theoretical approach to evaluating cross sections for partial photoneutron reactions are invoked in considering these problems.

Varlamov, V. V., E-mail: Varlamov@depni.sinp.msu.ru; Ishkhanov, B. S.; Orlin, V. N.; Peskov, N. N.; Stopani, K. A. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

2014-12-15T23:59:59.000Z

319

Energy Efficiency in Buildings in Switzerland  

E-Print Network [OSTI]

? Sensitivity to the decision procedure Based on experiences observed during these management seminars, the actual IEA annex 40 project of the Swiss shadow group is working to improve the com- petence of managers responsible for operation of the company.... SwissEnergy, Basic principles for optimum operation of complex installa- tions (OCI), EMDZ 805.220.1e, also published in the CD IEA Annex 40 2. SwissEnergy, Cost-efficiency arguments for optimum operation of com- plex installations...

Chuard, J.

2004-01-01T23:59:59.000Z

320

Quarkonium Production in PHENIX  

E-Print Network [OSTI]

Quarkonia provide a sensitive probe of the properties of the hot dense medium created in high energy heavy ion collisions. Hard scattering processes result in the production of heavy quark pairs that interact with the collision medium during hadronization. These in medium interactions convey information about the fundamental properties of the medium itself and can be used to examine the modification of the QCD confining potential in the collision environment. Baseline measurements from the d+Au and p+p collision systems can be used to distinguish cold nuclear matter effects while measurements from heavy ion collision systems, Au+Au and Cu+Cu, can be used to quantify in-medium effects. PHENIX results for the production of the $J/\\psi$ for a diverse set of collision systems and energies and for the $\\Upsilon$ in p+p collisions are presented.

Abigail Bickley; for the PHENIX Collaboration

2007-01-22T23:59:59.000Z

Note: This page contains sample records for the topic "antiknock in dex" 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

Cosmic rays in astrospheres  

E-Print Network [OSTI]

Cosmic rays passing through large astrospheres can be efficiently cooled inside these "cavities" in the interstellar medium. Moreover, the energy spectra of these energetic particles are already modulated in front of the astrospherical bow shocks. We study the cosmic ray flux in and around lambda Cephei as an example for an astrosphere. The large-scale plasma flow is modeled hydrodynamically with radiative cooling. We studied the cosmic ray flux in a stellar wind cavity using a transport model based on stochastic differential equations. The required parameters, most importantly, the elements of the diffusion tensor, are based on the heliospheric parameters. The magnetic field required for the diffusion coefficients is calculated kinematically. We discuss the transport in an astrospheric scenario with varying parameters for the transport coefficients. We show that large stellar wind cavities can act as sinks for the galactic cosmic ray flux and thus can give rise to small-scale anisotropies in the direction to...

Scherer, Klaus; Bomans, Dominik; Ferreira, Stefan; Fichtner, Horst; Kleimann, Jens; Strauss, Dutoit; Weis, Kerstin; Wiengarten, Tobias; Wodzinski, Thomas

2015-01-01T23:59:59.000Z

322

Foams in porous media  

SciTech Connect (OSTI)

In 1978 a literature search on selective blocking of fluid flow in porous media was done by Professor S.S. Marsden and two of his graduate students, Tom Elson and Kern Huppy. This was presented as SUPRI Report No. TR-3 entitled ''Literature Preview of the Selected Blockage of Fluids in Thermal Recovery Projects.'' Since then a lot of research on foam in porous media has been done on the SUPRI project and a great deal of new information has appeared in the literature. Therefore we believed that a new, up-to-date search should be done on foam alone, one which would be helpful to our students and perhaps of interest to others. This is a chronological survey showing the development of foam flow, blockage and use in porous media, starting with laboratory studies and eventually getting into field tests and demonstrations. It is arbitrarily divided into five-year time periods. 81 refs.

Marsden, S.S.

1986-07-01T23:59:59.000Z

323

Potential Vorticity in Magnetohydrodynamics  

E-Print Network [OSTI]

A version of Noether's second theorem using Lagrange multipliers is used to investigate fluid relabelling symmetries conservation laws in magnetohydrodynamics (MHD). We obtain a new generalized potential vorticity type conservation equation for MHD which takes into account entropy gradients and the ${\\bf J}\\times{\\bf B}$ force on the plasma due to the current ${\\bf J}$ and magnetic induction ${\\bf B}$. This new conservation law for MHD is derived by using Noether's second theorem in conjunction with a class of fluid relabelling symmetries in which the symmetry generator for the Lagrange label transformations is non-parallel to the magnetic field induction in Lagrange label space. This is associated with an Abelian Lie pseudo algebra and a foliated phase space in Lagrange label space. It contains as a special case Ertel's theorem in ideal fluid mechanics. An independent derivation shows that the new conservation law is also valid for more general physical situations.

G. M. Webb; R. L. Mace

2014-07-16T23:59:59.000Z

324

Observational learning in horses  

E-Print Network [OSTI]

OBSERVATIONAL LEARNING IN HORSES A Thesis by KATHERINE LOUISE BAER Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE May 1979 Major Subject: Animal... Science OBSERVATIONAL LEARNING IN HORSES A Thesis by KATHERINE LOUISE BAER Approved as to style and content by: L7 . 5+~ (Chairma of . C mmittee) ) c r (Mem ) YiNicc CJ ~- (Membeh) (Head of Department May 1979 ABSTRACT Observational...

Baer, Katherine Louise

1979-01-01T23:59:59.000Z

325

Livestock Auctions in Texas.  

E-Print Network [OSTI]

livestock needed by farmers are sold through the local market. This bulletin describes the local auctions in Texas with empha- sis on facilities, consignments, purchases, method of sale, trans- portation services and other important factors. The auctions... are I described by areas to permit comparisons of regional character- istics. The data summarized in the study pertain to 37 auctions / selected in 4 major geographical areas. The physical data are I supplemented by records of 35,000 sales...

McKenzie, Travis M. (Travis McDonald); Brotherton, Charles B. (Charles Benjamin); McNeely, John G.

1951-01-01T23:59:59.000Z

326

Astronomy in Argentina  

E-Print Network [OSTI]

This article analyses the current state of Astronomy in Argentina and describes its origins. We briefly describe the institutions where astronomical research takes place, the observational facilities available, the training of staff and professionals, and the role of the institutions in scientific promotion. We also discuss the outreach of Astronomy towards the general public, as well as amateur activities. The article ends with an analysis of the future prospects of astronomy in Argentina.

Muriel, Hernn

2013-01-01T23:59:59.000Z

327

Topics in String Phenomenology  

E-Print Network [OSTI]

We consider two questions in string ``phenomenology.'' First, are there any generic string predictions? Second, are there any general lessons which string theory suggests for thinking about low energy models, particularly in the framework of supersymmetry? Among the topics we consider are the squark and slepton spectrum, flavor symmetries, discrete symmetries including $CP$, and Peccei-Quinn symmetries. We also note that in some cases, discrete symmetries can be used to constrain the form of supersymmetry breaking.

Michael Dine

1993-09-23T23:59:59.000Z

328

Oak Poisoning in Livestock.  

E-Print Network [OSTI]

..-.......----------- - .............................. 3 . . Cllnlcal Signs and Lesions 4 . . Recent Studies on Oak Toxicity 4 Evaluations of Possible Antidotes ................................................................ 5 Methods of Chemical Control of Oak 8 Conclusions... this figure. Oak Poisoning in Livestock In 1936, Boughton and Hardy (3) reported severe losses among cattle and sheep eating Q. d?~~-u~dii var breviloba in the Edwards Plateau region of Texas. Q. gumbellii was reported by Marsh et al. (16) to be toxic...

Dollahite, J. W.; Housholder, G. T.; Camp, B. J.

1966-01-01T23:59:59.000Z

329

Graphics insertion in TEX  

E-Print Network [OSTI]

GRAPHICS INSERTION IN ~ A Thesis by GREGORY WILLIFORD KATTAWAR Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1989 Major Subject...: Computer Science GRAPHICS INSERTION IN TgX A Thesis by GREGORY WILLIFORD KATTAWAR Approved as to style and content by: S. Bart Childs (Chair of Committee) Norman W. Naugle (Member) Udo W. ooch (Member) Richard A. Volz (Head of Department...

Kattawar, Gregory Williford

1989-01-01T23:59:59.000Z

330

Experimental Theatre in Venezuela  

E-Print Network [OSTI]

4 LATIN AMERICAN THEATRE REVIEW Experimental Theatre in Venezuela The I Jornadas de Bsqueda y Experimentacin Teatral took place March 21-May 19, 1985 in Caracas. Organized by the Centro Latinoamericano de Creacin e Investigacin Teatral... of the festival was to give an opportunity for experimental theatre groups to present their work and thus to show the current tendencies of unconventional theatre in Venezuela. The participating groups (among them Shock Teatral, Contradanza, Taller...

Editors

1985-10-01T23:59:59.000Z

331

Lung Cancer and Arsenic Concentrations in Drinking Water in Chile  

E-Print Network [OSTI]

Lung Cancer and Arsenic Concentrations in Drinking Water in Chile Catterina Ferreccio,1,2 Claudia in northern Chile had arsenic concentrations of 860 g/liter in drinking water in the period 1958­1970. Concen and arsenic in drinking water in northern Chile in a case-control study involving patients diagnosed with lung

California at Berkeley, University of

332

Wind power in Brazil.  

E-Print Network [OSTI]

?? As welfare and industry production gets higher the demand for electricity increases. Almost 90 % of the electricity generated in Brazil is from renewable (more)

Elin, Karlsson

2009-01-01T23:59:59.000Z

333

Research in actinide chemistry  

SciTech Connect (OSTI)

This research studies the behavior of the actinide elements in aqueous solution. The high radioactivity of the transuranium actinides limits the concentrations which can be studied and, consequently, limits the experimental techniques. However, oxidation state analogs (trivalent lanthanides, tetravalent thorium, and hexavalent uranium) do not suffer from these limitations. Behavior of actinides in the environment are a major USDOE concern, whether in connection with long-term releases from a repository, releases from stored defense wastes or accidental releases in reprocessing, etc. Principal goal of our research was expand the thermodynamic data base on complexation of actinides by natural ligands (e.g., OH[sup [minus

Choppin, G.R.

1993-01-01T23:59:59.000Z

334

Imaging in Acute Stroke  

E-Print Network [OSTI]

National Institutes of Health stroke scale score in casesof hyperacute carotid ischemic stroke. AJNR Am J Neuroradiolin the evaluation of the subacute stroke patient, due to its

Birenbaum, Dale; Bancroft, Laura W; Felsberg, Gary J

2011-01-01T23:59:59.000Z

335

Essays in Public Economics  

E-Print Network [OSTI]

of what is so called the dot com bubble. First of all, Coiletriggered by the burst of dot com bubble in 2000, estimation

Lee, Insook

2013-01-01T23:59:59.000Z

336

Solar heating in Colombia.  

E-Print Network [OSTI]

?? This report describes the process of a thesis implemented in Colombia concerning solar energy. The project was to install a self-circulating solar heating system, (more)

Skytt, Johanna

2012-01-01T23:59:59.000Z

337

Tungsten diffusion in silicon  

SciTech Connect (OSTI)

Two doses (10{sup 13} and 10{sup 15}?cm{sup ?2}) of tungsten (W) atoms were implanted in different Si(001) wafers in order to study W diffusion in Si. The samples were annealed or oxidized at temperatures between 776 and 960?C. The diffusion profiles were measured by secondary ion mass spectrometry, and defect formation was studied by transmission electron microscopy and atom probe tomography. W is shown to reduce Si recrystallization after implantation and to exhibit, in the temperature range investigated, a solubility limit close to 0.15%0.2%, which is higher than the solubility limit of usual metallic impurities in Si. W diffusion exhibits unusual linear diffusion profiles with a maximum concentration always located at the Si surface, slower kinetics than other metals in Si, and promotes vacancy accumulation close to the Si surface, with the formation of hollow cavities in the case of the higher W dose. In addition, Si self-interstitial injection during oxidation is shown to promote W-Si clustering. Taking into account these observations, a diffusion model based on the simultaneous diffusion of interstitial W atoms and W-Si atomic pairs is proposed since usual models used to model diffusion of metallic impurities and dopants in Si cannot reproduce experimental observations.

De Luca, A.; Texier, M.; Burle, N.; Oison, V.; Pichaud, B. [Aix-Marseille Universit, IM2NP UMR 7334, Facult des Sciences et Techniques, Campus de Saint-Jrme, Avenue Escadrille Normandie Niemen - Case 142, F-13397 Marseille Cedex (France); Portavoce, A., E-mail: alain.portavoce@im2np.fr [CNRS, IM2NP UMR 7334, Facult des Sciences et Techniques, Campus de Saint-Jrme, Avenue Escadrille Normandie Niemen - Case 142, F-13397 Marseille Cedex (France); Grosjean, C. [STMicroelectronics, Rousset (France)

2014-01-07T23:59:59.000Z

338

Spin waves in the (  

SciTech Connect (OSTI)

We use neutron scattering to show that spin waves in the iron chalcogenide Fe{sub 1.05}Te display novel dispersion clearly different from both the first principles density functional calculations and recent observations in the related iron pnictide CaFe{sub 2}As{sub 2}. By fitting to a Heisenberg Hamiltonian, we find that although the nearest-neighbor exchange couplings in the two systems are quite different, their next-nearest-neighbor (NNN) couplings are similar. This suggests that superconductivity in the pnictides and chalcogenides share a common magnetic origin that is intimately associated with the NNN magnetic coupling between the irons.

Lipscombe, O. J. [University of Tennessee, Knoxville (UTK); Chen, G. F. [The Institute of Physics, Chinese Academy of Sciences; Fang, Chen [Purdue University; Perring, T. G. [ISIS Facility, Rutherford Appleton Laboratory; Abernathy, Douglas L [ORNL; Christianson, Andrew D [ORNL; Egami, Takeshi [ORNL; Wang, Nanlin [The Institute of Physics, Chinese Academy of Sciences; Hu, Jiangping [Purdue University and Chinese Academy of Sciences; Dai, Pengcheng [University of Tennessee, Knoxville (UTK)

2011-01-01T23:59:59.000Z

339

Confusion in Thermodynamics  

E-Print Network [OSTI]

For a long time now, confusion has existed in the minds of many over the meaning of various concepts in thermodynamics. Recently, this point has been brought to people's attention by two articles appearing on the well-known archive (arxiv) web site. The content of these two pieces serves to illustrate many of the problems and has occasioned the construction of this answer to at least some of them. The position of the axiom proposed by Carath\\'eodory is central in this matter and here its position is clarified and secured within the framework of thermodynamics. In particular, its relation to the First Law is examined and justified.

Jeremy Dunning-Davies; David Sands

2011-05-17T23:59:59.000Z

340

Essays in Environmental Economics  

E-Print Network [OSTI]

vineyards due to these water shortages (DWR, 2012). Whilecosts of irrigation water shortages. Bibliography [1] Alexto a severe shortage of surface irrigation water. In one of

Foreman, Kathleen

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "antiknock in dex" 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

Work in Horticulture.  

E-Print Network [OSTI]

ripe n~ildly sub-acid. AJIARELLE BUNT. Another variety of the Red Dnkes much prized in iSorth Sile~ia for dessert use and cooking. A tine grower in orchard and nursery and far hardier tree on onr grounds than Richmond or Eng1i.h Morello; mainly I... 100 TEXAS AGRICU1,TI:RAL EXPERIMENT STATIOS. think on account of its Ixmre perfect foliage. The fruit is highly prized in the markets of Warsaw, Poland. SPATE: AXARXLLE. IIZuc11 grown for dessert and culinary nse in East Poland and Worth Bileam...

Beach, S. A. (Spencer Ambrose)

1891-01-01T23:59:59.000Z

342

In Situ Processing  

E-Print Network [OSTI]

Apr. 2010. [42] Fang Zheng, Hasan Abbasi, Jianting Cao, JaiNobert Podhorszki, and Hasan Abbasi. Enabling In-situis required. References [1] Hasan Abbasi, Greg Eisenhauer,

Childs, Hank

2013-01-01T23:59:59.000Z

343

Insurgency in Academic Publishing  

E-Print Network [OSTI]

read, and share academic articles. Gowers argued thatresearch. Academic journals, like the BPJ, solicit articles,s article found ample kindling in the academic community

Miller, Ruth

2012-01-01T23:59:59.000Z

344

Scattering in an environment  

E-Print Network [OSTI]

The cross section of elastic electron-proton scattering taking place in an electron gas is calculated within the Closed Time Path method. It is found to be the sum of two terms, one being the expression in the vacuum except that it involves dressing due to the electron gas. The other term is due to the scattering particles-electron gas entanglement. This term dominates the usual one when the exchange energy is in the vicinity of the Fermi energy. Furthermore it makes the trajectories of the colliding particles more consistent and the collision more irreversible, rendering the scattering more classical in this regime.

Janos Polonyi; Karima Zazoua

2012-03-11T23:59:59.000Z

345

Excitons in Electrostatic Lattices /  

E-Print Network [OSTI]

modern day photovoltaics, optoelectronics, plasmonics, andand every advance in optoelectronics requires a new level ofdevelopment of both optoelectronics and photovoltaics. The

Remeika, Mikas

2013-01-01T23:59:59.000Z

346

Definability in Physics  

E-Print Network [OSTI]

This paper has been withdrawn because the content has been substantially improved in a later paper, arXiv:0806.1165.

David J. BenDaniel

2006-06-26T23:59:59.000Z

347

Hard physics in PHENIX  

E-Print Network [OSTI]

We review recent results on hard observables in p+p, d+A and A+A collisions obtained by the PHENIX experiment. Emphasis is put on those measurements that provide insight into the properties of hot QCD media expected to be created in nucleus-nucleus collisions at RHIC energies. Direct photon spectra, jet properties and heavy quarks production measured in p+p and d+Au collisions are compared to the same observables extracted in heavy ion collisions to find modifications due to the presence of hot QCD matter.

D. Peressounko; for the PHENIX collaboration

2005-12-08T23:59:59.000Z

348

Astronomy in Ukraine  

E-Print Network [OSTI]

The current and prospective status of astronomical research in Ukraine is discussed. A brief history of astronomical research in Ukraine is presented and the system organizing scientific activity is described, including astronomy education, institutions and staff, awarding higher degrees/titles, government involvement, budgetary investments and international cooperation. Individuals contributing significantly to the field of astronomy and their accomplishments are mentioned. Major astronomical facilities, their capabilities, and their instrumentation are described. In terms of the number of institutions and personnel engaged in astronomy, and of past accomplishments, Ukraine ranks among major nations of Europe. Current difficulties associated with political, economic and technological changes are addressed and goals for future research activities presented.

Ya. V. Pavlenko; I. B. Vavilova; T. Kostiuk

2005-12-16T23:59:59.000Z

349

Gravity in Gauge Mediation  

E-Print Network [OSTI]

We investigate O'Raifeartaigh-type models for F-term supersymmetry breaking in gauge mediation scenarios in the presence of gravity. It is pointed out that the vacuum structure of those models is such that in metastable vacua gravity mediation contribution to scalar masses is always suppressed to the level below 1 percent, almost sufficient for avoiding FCNC problem. Close to that limit, gravitino mass can be in the range 10-100 GeV, opening several interesting possibilities for gauge mediation models, including Giudice-Masiero mechanism for mu and Bmu generation. Gravity sector can include stabilized moduli.

Zygmunt Lalak; Stefan Pokorski; Krzysztof Turzynski

2008-08-18T23:59:59.000Z

350

Essays in Energy Economics  

E-Print Network [OSTI]

is apparent in the electricity consumption behavior ofuncorrelated with electricity consumption on any given day.correlated with electricity consumption, 15 I compare the

Spurlock, Cecily Anna

2013-01-01T23:59:59.000Z

351

Adventures in Infectious Diseases  

ScienceCinema (OSTI)

Dr. Susan Fisher-Hoch, Virologist and Epidemiologist, will discuss her research and travels associated with viral hemorrhagic fevers. From the Ebola outbreak in Reston, Virginia to outbreaks of Crimean Congo Hemorrhagic Fever in South Africa, Senegal, and Saudi Arabia, Dr. Fisher-Hoch has studied and tracked the pathophysiology of these viral diseases. These studies have led her from the Center for Disease Control in the United States, to Lyon, France where she was instrumental in designing, constructing, and rendering operational a laboratory capable of containing some of the world's most dangerous diseases.

Fisher-Hoch, Susan [University of Texas School of Public Health

2014-06-25T23:59:59.000Z

352

VIOLENT FRAMES IN ACTION  

SciTech Connect (OSTI)

We present a computational approach to radical rhetoric that leverages the co-expression of rhetoric and action features in discourse to identify violent intent. The approach combines text mining and machine learning techniques with insights from Frame Analysis and theories that explain the emergence of violence in terms of moral disengagement, the violation of sacred values and social isolation in order to build computational models that identify messages from terrorist sources and estimate their proximity to an attack. We discuss a specific application of this approach to a body of documents from and about radical and terrorist groups in the Middle East and present the results achieved.

Sanfilippo, Antonio P.; McGrath, Liam R.; Whitney, Paul D.

2011-11-17T23:59:59.000Z

353

in the Sciences Mathematics  

E-Print Network [OSTI]

.mis.mpg.de/al APPLICATIONS should be submitted by May 31, 2014, at Nihat Ay MPI for Mathematics in the Sciences Marc

354

Library legislation in Zambia.  

E-Print Network [OSTI]

??This dissertation investigates and justifies the need for a public library law in Zambia to lay the foundation for the provision and development of public (more)

Kantumoya, Albert

2010-01-01T23:59:59.000Z

355

What's In My Water?  

E-Print Network [OSTI]

.The salts in conductivity levels are conductivity levels. allow for too much water to evaporate water are not just table high, evaluate other from the surface, or where soils are salt, but are often a individual characteristics naturally high in salts...- tive safety margin. You can have your water analyzed by a government agency or a private company. 13 Salt: an organic or inorganic com- pound that is subject to dissociation when water is added, resulting in a dis- tinct increase in specific anions...

Provin, Tony; Pitt, John L.

2003-04-21T23:59:59.000Z

356

Plasmons in strong superconductors  

E-Print Network [OSTI]

We present a study of the possible plasmon excitations that can occur in systems where strong superconductivity is present. In these systems the plasmon energy is comparable to, or smaller than the pairing gap. As a prototype of these systems we consider the proton component of neutron star matter just below the crust when electron screening is not taken into account. For the realistic case we consider in detail the different aspects of the elementary excitations when the proton, electron components are considered within the Random Phase Approximation generalized to the superfluid case, while the influence of the neutron component is considered only at qualitative level. Electron screening plays a major role in modifying the proton spectrum and spectral function. At the same time the electron plasmon is strongly modified and damped by the indirect coupling with the superfluid proton component, even at moderately low values of the gap. The excitation spectrum shows the interplay of the different components and their relevance for each excitation mode. The results are relevant for neutrino physics and thermodynamical processes in neutron stars. If electron screening is neglected, the spectral properties of the proton component show some resemblance with the physical situation in high T$_c$ superconductors, and we briefly discuss similarities and differences in this connection. In a general prospect, the results of the study emphasize the role of Coulomb interaction in strong superconductors.

Marcello Baldo; Camille Ducoin

2011-06-07T23:59:59.000Z

357

Physical Vacuum in Superconductors  

E-Print Network [OSTI]

Although experiments carried out by Jain et al. showed that the Cooper pairs obey the strong equivalence principle, The measurement of the Cooper pairs inertial mass by Tate et al. revealed an anomalous excess of mass. In the present paper we interpret these experimental results in the framework of an electromagnetic model of dark energy for the superconductors' vacuum. We argue that this physical vacuum is associated with a preferred frame. Ultimately from the conservation of energy for Cooper pairs we derive a model for a variable vacuum speed of light in the superconductors physical vacuum in relation with a possible breaking of the weak equivalence principle for Cooper pairs.

Clovis Jacinto de Matos

2009-08-31T23:59:59.000Z

358

Scheduling in Multiprocess Systems  

E-Print Network [OSTI]

In RTSS, Lisbon, Portugal, [46] Facebook. Facebook. http://www.facebook.com. [47] Facebook.Facebook info.php? statistics, 2011. statistics. http://

Dou, Ji Adam

2011-01-01T23:59:59.000Z

359

Computer Forensics In Forensis  

E-Print Network [OSTI]

U.N. In Proceedings of CMAD IV: Computer Misuse and Anomaly4] J. P. Anderson. Computer Security Threat Monitoring andof the Fifth Annual Computer Security Applications

Peisert, Sean; Bishop, Matt; Marzullo, Keith

2008-01-01T23:59:59.000Z

360

Hybrid Vigor in Sorghum.  

E-Print Network [OSTI]

of the relia.ble measures of hybrid vigor, these height measurements furnish a means of estimating hybrid vigor in crosses. Materials The materials used in this study include the three strains of milo known as Extra Dwarf, Dwarf, and Standard; and three... strains of feterita known as Extra Dwarf, Dwarf, and Standard. It is note- worthy that in both milo and feterita parallel forms have been devel- oped in so far as stature is concerned. The mean height for Extra Dwarf milos and feteritas ranged from 56...

Conner, A. B. (Arthur Benjamin)

1927-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "antiknock in dex" 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

Corruption in Uganda  

E-Print Network [OSTI]

of corruption in Uganda? Causes and Consequences ofto January 24, 1986, Uganda has lacked exemplary leadership.the Central Bank (Bank of Uganda). If salary and wage rises

Nsibambi, Apolo

1987-01-01T23:59:59.000Z

362

Global developments in MTBE  

SciTech Connect (OSTI)

This paper is intended to provide an overview of some of the recent developments in MTBE demand growth worldwide and the impact of these developments on MTBE demand in the future. It provides a perspective of the influence of developments in the US on the worldwide MTBE markets. The public`s outcry regarding oxygenates in gasoline, and specifically MTBE, that has been evolving in the US during the past several months is in response to a politically mandated requirement for a fuel that contains oxygen that is provided by MTBE or ethanol. This public unrest had negatively impacted the market price for MTBE at the time this paper was being prepared. However, the author believes that MTBE, because of its clean octane capabilities, will continue to be used as an octane blendstock for gasoline in increasing quantities worldwide as we move through lead phasedown in West Europe and other countries that are experiencing pollution problems relating to exhaust emissions from internal combustion engines. The objectives of this paper are as follows: review developments in MTBE demand 1990--2000; identify regions where MTBE demand growth will occur; review production growth for MTBE, both historical and forecast; examine world trade patterns during the period; assess methanol demand growth during the period; analyze MTBE`s regional price bias; and provide a forecast of future MTBE price trends.

Feller, L.W. [CMAI, Houston, TX (United States)

1995-12-31T23:59:59.000Z

363

Excitons in Electrostatic Lattices /  

E-Print Network [OSTI]

6.4 Exciton Energy and Intensity Modulation Measurement .6.4: Observable energy and intensity modulation at differentmodulations in energy and intensity (red, right magnified

Remeika, Mikas

2013-01-01T23:59:59.000Z

364

In China's Mirror  

E-Print Network [OSTI]

of California, Berkeley In Chinas Mirror * Antnio Barrosthe article No Espelho da China, which originally appearedThomas, Produtos Baratos da China Facilitam a Vida de

Barros de Castro, Antnio

2012-01-01T23:59:59.000Z

365

Advances in Physical Chemistry  

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

Hindawi Publishing Corporation Advances in Physical Chemistry Volume 2011, Article ID 907129, 18 pages doi:10.11552011907129 Review Article Contrast and Synergy between...

366

Caught in the Act  

SciTech Connect (OSTI)

Representing the Center for Defect Physics (CDP), this document is one of the entries in the Ten Hundred and One Word Challenge. As part of the challenge, the 46 Energy Frontier Research Centers were invited to represent their science in images, cartoons, photos, words and original paintings, but any descriptions or words could only use the 1000 most commonly used words in the English language, with the addition of one word important to each of the EFRCs and the mission of DOE: energy. The mission of the CDP is to enhance our fundamental understanding of defects, defect interactions, and defect dynamics that determine the performance of structural materials in extreme environments.

Stocks, G. Malcolm; Morris, James; Sproles, Andrew; Henson, Priscilla; Graham, Kathy

2013-07-18T23:59:59.000Z

367

Ergonomics in the Biosciences  

E-Print Network [OSTI]

Gilson (ND) Laboratory ergonomics: Things you should knowMason E, Dukes S (2003 ). Ergonomics and cytotechnologists:Ergonomics in the Biosciences Ira Janowitz, PT, CPE Lawrence

Janowitz, Ira

2010-01-01T23:59:59.000Z

368

Phonon dispersion in graphene  

E-Print Network [OSTI]

Taking into account the constraints imposed by the lattice symmetry, the phonon dispersion is calculated for graphene with interactions between the first and second nearest neighbors in the framework of the Born-von Karman model. Analytical expressions are obtained for the out-of-plane (bending) modes determined only by two force constants as well as for the in-plane modes with four force constants. Values of the force constants are found in fitting to elastic constants and Raman frequencies observed in graphite.

L. A. Falkovsky

2007-08-11T23:59:59.000Z

369

ALS in the News  

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 Jun Jul(Summary)morphinanInformation InInformation InExplosion Monitoring:Home|PhysicsGasandArgonneALS in the News ALS in the

370

ALS in the News  

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 Jun Jul(Summary)morphinanInformation InInformation InExplosion Monitoring:Home|PhysicsGasandArgonneALS in the News ALS in

371

Petroleum industry in Iran  

SciTech Connect (OSTI)

This study examines the oil industry in Iran from the early discovery of oil nearly two hundred years ago in Mazandaran (north part) to the development of a giant modern industry in the twentieth century. Chapter I presents a brief historical setting to introduce the reader to the importance of oil in Iran. It focuses on the economic implications of the early oil concessions in the period 1901 to 1951. Chapter II discusses the nationalization of the Iranian oil industry and creation of NIOC in 1951 and the international political and economic implication of these activities. Chapter III explains the activities of NIOC in Iran. Exploration and drilling, production, exports, refineries, natural gas, petrochemicals and internal distributions are studied. Chapter IV discusses the role of the development planning of Iran. A brief presentation of the First Development Plan through the Fifth Development Plan is given. Sources and uses of funds by plan organization during these Five Plans is studied. The Iran and Iraq War is also studied briefly, but the uncertainty of its resolution prevents any close analysis of its impact on the Iranian oil industry. One conclusion, however, is certain; oil has been a vital resource in Iran's past and it will remain the lifetime of its economic development in the future.

Farideh, A.

1981-01-01T23:59:59.000Z

372

Symmetry in Scheduling Problems  

E-Print Network [OSTI]

Nov 16, 2010 ... Using operating room and power generator scheduling problems ... Symmetry has been an obstacle in mixed integer linear programming...

2010-11-16T23:59:59.000Z

373

Counterterms in Lovelock Gravity  

E-Print Network [OSTI]

In this paper, we introduce the counterterms that remove the non-logarithmic divergences of the action in third order Lovelock gravity. We do this by defining the cosmological constant in such a way that the asymptotic form of the metric have the same form in Lovelock and Einstein gravities. Thus, we employ the counterterms of Einstein gravity and show that the power law divergences in the action of Lovelock gravity can be removed by suitable choice of coefficients. We find that the dependence of these coefficients on the dimension in Lovelock gravity is the same as in Einstein gravity. We also introduce the finite energy-momentum tensor and employ these counterterms to calculate the finite action and mass of the black hole solutions of third order Lovelock gravity. We calculate the thermodynamic quantities and show that the entropy calculated through the use of Gibbs-Duhem relation is consistent with the obtained entropy by Wald's formula. We, also, find that in contrast to Einstein gravity in which there ex...

Mehdizadeh, M R; Zangeneh, M Kord

2015-01-01T23:59:59.000Z

374

In other news  

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 withconfinementEtching.348 270 300Aptamers and GraphenePhaseNewsaInInInIn

375

In other news  

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 withconfinementEtching.348 270 300Aptamers andIn other news CommunityInInIn

376

(Ionization in liquids)  

SciTech Connect (OSTI)

This document describes charge transport following ionization of model liquids and how this process may be important in carcinogenesis. 15 refs., 2 figs., 4 tabs. (MHB)

Not Available

1991-01-01T23:59:59.000Z

377

URANIUM IN ALKALINE ROCKS  

E-Print Network [OSTI]

Greenland," in Uranium Exploration Geology, Int. AtomicOklahoma," 1977 Nure Geology Uranium Symposium, Igneous HostMcNeil, M. , 1977. "Geology of Brazil's Uranium and Thorium

Murphy, M.

2011-01-01T23:59:59.000Z

378

Eliminating MTBE in Gasoline in 2006  

Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

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) " ,"ClickPipelines AboutDecemberSteam Coal Import96Nebraska NuclearDecade Year-08/03)1 Eliminating MTBE in

379

MATLAB Einfuhrung Einfuhrung in  

E-Print Network [OSTI]

MATLAB Einf¨uhrung Einf¨uhrung in MATLAB FB Physik, Mathematik & Informatik · Johannes Gutenberg;Was ist MATLAB? MATLAB (Matrix Laboratory) ist eine interaktive Interpreter-Sprache, die einen einfa Gleichungssysteme oder ¨ahnlichem ­ bietet. Wie startet man MATLAB? In den Rechner-Pools im 3., 4. oder 5. Stock des

Hanke-Bourgeois, Martin

380

Geothermal energy in Nevada  

SciTech Connect (OSTI)

The nature of goethermal resources in Nevada and resource applications are discussed. The social and economic advantages of utilizing geothermal energy are outlined. Federal and State programs established to foster the development of geothermal energy are discussed. The names, addresses, and phone numbers of various organizations actively involved in research, regulation, and the development of geothermal energy are included. (MHR)

Not Available

1980-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "antiknock in dex" 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

Progress in colloid propulsion  

E-Print Network [OSTI]

In the early decades of the Space Age, a great deal of work was put into the development of the Colloid Thruster as an electric propulsion system for spacecraft. In spite of the effort by the end of the 70s the programs ...

Lpez Urdiales, Jse Mariano, 1977-

2004-01-01T23:59:59.000Z

382

ARTICLE IN PRESS Automatica ( )  

E-Print Network [OSTI]

ARTICLE IN PRESS Automatica ( ) Contents lists available at ScienceDirect Automatica journal parameter, the regularization constant which is used to trade-off fit and the number of segments. 2010 or equals the number of observations we would get a perfect fit, at the price of models that adjust in every

383

Engineering in Process Metallurgy  

E-Print Network [OSTI]

MATS3003 Engineering in Process Metallurgy Course Outline Session 1, 2014 School of Materials ................................................................................................... 7 Course Objective To introduce the basic operations in process metallurgy and to provide Course at a Glance What you will learn Weeks Assessment Task Introduction - What is process metallurgy

New South Wales, University of

384

in this issue Visualising  

E-Print Network [OSTI]

in this issue Visualising Evolutionary Search Spaces James McDermott Unshackling Evolution Nick just published new Master or PhD theses, if you want to let our community know how your workshop) that you wish to advertise, just drop me an email. In this issue we have a new article by James Mc

Fernandez, Thomas

385

Environmental gentrification in Berlin  

E-Print Network [OSTI]

In an age of rising global environmental concerns, cities have come to play a key role in managing environmental issues such as climate change and food security on more regional and local scales and thus have become the locus for sustainable...

Schroder, Nina

386

International Programs in Agriculture  

E-Print Network [OSTI]

International Programs in Agriculture MessagefromtheDirector­ Staying Ahead of Globalization and more prosperous place for all. Fortunately, Purdue International Programs in Agriculture (IPIA) has natural disasters caution us to remember the power of nature. The United Nations Food and Agriculture

387

Photon Physics in ALICE  

E-Print Network [OSTI]

We give an overview of photon physics which will be studied by the ALICE experiment in proton-proton and heavy ion collisions at LHC. We compare properties of ALICE photon detectors and estimate their ability to measure neutral meson and direct photon spectra as well as gamma-hadron and gamma-jet correlations in pp and Pb+Pb collisions.

D. Peressounko; Y. Kharlov; for the ALICE collaboration

2009-07-16T23:59:59.000Z

388

in Condensed Matter Physics  

E-Print Network [OSTI]

Master in Condensed Matter Physics ­ Master académique #12;2 #12;3 Students at the University. Condensed matter physics is about explaining and predicting the relationship between the atomic, and broad education in the field of condensed matter physics · introduce you to current research topics

van der Torre, Leon

389

study programs in mathematics  

E-Print Network [OSTI]

study programs in m mathematics 1_ matematika 2008.qxp 16.7.2008 16:41 Page 1 #12;1_ matematika 2008.qxp 16.7.2008 16:41 Page 2 #12;3 CONTENTS 5 Introduction 7 Mathematics at the University of Ljubljana 9 Department of Mathematics information page Academic study program in Mathematics Academic study

?umer, Slobodan

390

Research Frontiers in Environmental  

E-Print Network [OSTI]

September 15, 1998 Editors: Bruce E. Logan Charles R. O'Melia Bruce E. Rittmann A Report of a Workshop On January 14-16, 1998, a meeting was held at the Asilomar Conference Center in Monterey, California Chairs, Bruce Logan and Charles O'Melia, based on either membership in the National Academy

391

High Performance Computing in  

E-Print Network [OSTI]

High Performance Computing in Bioinformatics Thomas Ludwig (t.ludwig@computer.org) Ruprecht PART I: High Performance Computing Thomas Ludwig PART II: HPC Computing in Bioinformatics Alexandros #12;© Thomas Ludwig, Alexandros Stamatakis, GCB'04 3 PART I High Performance Computing Introduction

Stamatakis, Alexandros

392

Renewable Energy in Alaska  

SciTech Connect (OSTI)

This report examines the opportunities, challenges, and costs associated with renewable energy implementation in Alaska and provides strategies that position Alaska's accumulating knowledge in renewable energy development for export to the rapidly growing energy/electric markets of the developing world.

Not Available

2013-03-01T23:59:59.000Z

393

ARTICLE IN PRESS UNCORRECTEDPROOF  

E-Print Network [OSTI]

frequency harmonics arrive at the focusing location in phase, a very steep wave single emerges evolution; Bound (locked) waves 1. Introduction Generation of very steep waves in wave tanks enables experimental study of the wave damage potential and is thus of great importance. Excitation of a single steep

Shemer, Lev

394

Silica in Protoplanetary Disks  

E-Print Network [OSTI]

Mid-infrared spectra of a few T Tauri stars (TTS) taken with the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope show prominent narrow emission features indicating silica (crystalline silicon dioxide). Silica is not a major constituent of the interstellar medium; therefore, any silica present in the circumstellar protoplanetary disks of TTS must be largely the result of processing of primitive dust material in the disks surrouding these stars. We model the silica emission features in our spectra using the opacities of various polymorphs of silica and their amorphous versions computed from earth-based laboratory measurements. This modeling indicates that the two polymorphs of silica, tridymite and cristobalite, which form at successively higher temperatures and low pressures, are the dominant forms of silica in the TTS of our sample. These high temperature, low pressure polymorphs of silica present in protoplanetary disks are consistent with a grain composed mostly of tridymite named Ada found in the cometary dust samples collected from the STARDUST mission to Comet 81P/Wild 2. The silica in these protoplanetary disks may arise from incongruent melting of enstatite or from incongruent melting of amorphous pyroxene, the latter being analogous to the former. The high temperatures of 1200K-1300K and rapid cooling required to crystallize tridymite or cristobalite set constraints on the mechanisms that could have formed the silica in these protoplanetary disks, suggestive of processing of these grains during the transient heating events hypothesized to create chondrules.

B. A. Sargent; W. J. Forrest; C. Tayrien; M. K. McClure; A. Li; A. R. Basu; P. Manoj; D. M. Watson; C. J. Bohac; E. Furlan; K. H. Kim; J. D. Green; G. C. Sloan

2008-11-21T23:59:59.000Z

395

Proceedings in MANUFACTURING  

E-Print Network [OSTI]

: robot arm, rigidity, milling stability, dynamic identification 1. INTRODUCTION Industrial robots. EXPERIMENTAL CHARACTERIZATION OF ROBOT ARM RIGIDITY IN ORDER TO BE USED IN MACHINING OPERATION Jean-Yves K at the end of a robot arm poly-articulated date back twenty years, but these robots were not designed

Paris-Sud XI, Université de

396

Asparagine metabolism in rats  

E-Print Network [OSTI]

-scintillation counting. Except for monitoring column effluent, sll C assays were done in a Nuclear-Chicago Modular 4 Mark I Liquid Scintillation System using the published liquid scintillation counting technique of Bruno and Christian (26). In i all cases, samples...

Harper, John Colquitt

2012-06-07T23:59:59.000Z

397

Concentration in Green Design  

E-Print Network [OSTI]

, energy, infrastructure or transport. Participants in this specialization area work closely with the GreenConcentration in Green Design Research and Education Opportunities Carnegie Mellon University Civil and Environmental Engineering www.ce.cmu.edu M.S. Concentration Green Design - Course Only Track As an extension

Shewchuk, Jonathan

398

Sustainability in colleges 15  

E-Print Network [OSTI]

Sustainability in colleges 15 Carbon reduction 5 Water 7 Travel8 Waste,recyclingandreuse10 Sustainability Report 2011/2012 #12;2University of Oxford Environmental Sustainability Report 2011/12 "As Chair of the Sustainability Steering Group, I have seen a significant shift in staff and students' expectations

Melham, Tom

399

Fire in Buildings  

E-Print Network [OSTI]

During the lifetime of any building in Canada it is probable that one or more "unwanted" fires will occur. "Fire Loss in Canada, 1959," the report of the Dominion Fire Commissioner, states that for the period 1950-1959 the average number of reported...

Shorter, G.

400

Genetics in the courts  

SciTech Connect (OSTI)

Various: (1)TriState 2000 Genetics in the Courts (2) Growing impact of the new genetics on the courts (3)Human testing (4) Legal analysis - in re G.C. (5) Legal analysis - GM ''peanots'', and (6) Legal analysis for State vs Miller

Coyle, Heather; Drell, Dan

2000-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "antiknock in dex" 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

Energietransitie in Brainport  

E-Print Network [OSTI]

(Chemische Technologie) ­ Afstuderen: Adoption and diffusion of energy innovations in smallscale rural industries of Cochabamba, Bolivia. #12;2003: Energietransitie in Bolivië Transitie van biomassa naar gas · Local for local (vraag en aanbod) · Duurzaam en decentraal · Power to the people ­ Morgen Groene Energie

Franssen, Michael

402

Work in Horticulture.  

E-Print Network [OSTI]

, although makes a good crop in East Texas. 5 and 6. 1sabella.-A heavy growth in spring, with a little Anthracnose. Produced three bunches. By fall had made a 20-foot growth; affected to some extent by Spot Disease and Anthracnose, and considerably by Le...

Brunk, T. L.

1889-01-01T23:59:59.000Z

403

Equity in international agreements  

SciTech Connect (OSTI)

Approaches to establishing equitable greenhouse gas emission policies among different nations are briefly discussed. The impact of energy efficiency is proposed as an aid to equitable resource distribution. A comprehensive approach which would account for changes in net greenhouse gases is discussed. In addition, international trading of net greenhouse gas emissions reduction credits is proposed.

Stewart, R. [Georgetown Univ. Law Center, Washington, DC (United States)

1992-12-31T23:59:59.000Z

404

PCBs found in PILC  

SciTech Connect (OSTI)

A number of utilities have discovered polychlorinated biphenyls (PCBs) in paper-insulated, lead-covered cable (PILIC) systems. The extent of this problem is of such concern that it is included in the regulatory revisions currently being proposed by the US Environmental Protection Agency (EPA). The vast number of these systems, together with results form our studies virtually assures the widespread presence of PCBs in underground systems. The dual hazards associated with exposure of lead to humans and acceptance of the presence of PCBs in cable is forcing companies to develop sophisticated testing and new maintenance procedures. Age old disposal practices suspected of contaminating scarp yards and exposing workers to lead poisoning will be phased out in favor of controlled, indoor operations developed specifically for the safe disposal of this material.

Lauterback, S.

1996-11-01T23:59:59.000Z

405

Irradiation Creep in Graphite  

SciTech Connect (OSTI)

An understanding of the underlying mechanisms of irradiation creep in graphite material is required to correctly interpret experimental data, explain micromechanical modeling results, and predict whole-core behavior. This project will focus on experimental microscopic data to demonstrate the mechanism of irradiation creep. High-resolution transmission electron microscopy should be able to image both the dislocations in graphite and the irradiation-induced interstitial clusters that pin those dislocations. The team will first prepare and characterize nanoscale samples of virgin nuclear graphite in a transmission electron microscope. Additional samples will be irradiated to varying degrees at the Advanced Test Reactor (ATR) facility and similarly characterized. Researchers will record microstructures and crystal defects and suggest a mechanism for irradiation creep based on the results. In addition, the purchase of a tensile holder for a transmission electron microscope will allow, for the first time, in situ observation of creep behavior on the microstructure and crystallographic defects.

Ubic, Rick; Butt, Darryl; Windes, William

2014-03-13T23:59:59.000Z

406

HNCO in molecular clouds  

SciTech Connect (OSTI)

In a survey of 18 molecular clouds, HNCO J/sub K/-1K1..-->..J'/sub K/'-1K'1 = 5/sub 05/..-->..4/sub 05/ and 4/sub 04/..-->..3/sub 03/ emission was etected in seven clouds, and possibly in one other. Emission in these transitions originates in high-density regions (n> or approx. =10/sup 6/ cm/sup -3/). The molecule's excitation requirements allow us to derive limits to excitation temperatures an optical depths. We discuss the possibility of clumping with respect to the beam and compare our results with data from other molecular species. The HNCO emission from Sgr A is an ordder of magnitude larger than the other detected sources as is the ratio ..delta..T +- /sub A/(HNCO 5/sub 05/..-->..4/sub 04/)/..delta..T +- /sub A/(C/sup 18/O 1..-->..0). HNCO is probably a constituent of most molecular clouds.

Jackson, J.M.; Armstrong, J.T.; Barrett, A.H.

1984-05-15T23:59:59.000Z

407

Measuring Value in Healthcare  

E-Print Network [OSTI]

A statistical description and model of individual healthcare expenditures in the US has been developed for measuring value in healthcare. We find evidence that healthcare expenditures are quantifiable as an infusion-diffusion process, which can be thought of intuitively as a steady change in the intensity of treatment superimposed on a random process reflecting variations in the efficiency and effectiveness of treatment. The arithmetic mean represents the net average annual cost of healthcare; and when multiplied by the arithmetic standard deviation, which represents the effective risk, the result is a measure of healthcare cost control. Policymakers, providers, payors, or patients that decrease these parameters are generating value in healthcare. The model has an average absolute prediction error of approximately 10-12% across the range of expenditures which spans 6 orders of magnitude over a nearly 10-year period. For the top 1% of the population with the largest expenditures, representing 20%-30% of total ...

Gardner, Christopher

2008-01-01T23:59:59.000Z

408

Developments in GRworkbench  

E-Print Network [OSTI]

The software tool GRworkbench is an ongoing project in visual, numerical General Relativity at The Australian National University. Recently, GRworkbench has been significantly extended to facilitate numerical experimentation in analytically-defined space-times. The numerical differential geometric engine has been rewritten using functional programming techniques, enabling objects which are normally defined as functions in the formalism of differential geometry and General Relativity to be directly represented as function variables in the C++ code of GRworkbench. The new functional differential geometric engine allows for more accurate and efficient visualisation of objects in space-times and makes new, efficient computational techniques available. Motivated by the desire to investigate a recent scientific claim using GRworkbench, new tools for numerical experimentation have been implemented, allowing for the simulation of complex physical situations.

A. Moylan; S. M. Scott; A. C. Searle

2005-08-24T23:59:59.000Z

409

Strangeness in Neutron Stars  

E-Print Network [OSTI]

It is generally agreed on that the tremendous densities reached in the centers of neutron stars provide a high-pressure environment in which several intriguing particles processes may compete with each other. These range from the generation of hyperons to quark deconfinement to the formation of kaon condensates and H-matter. There are theoretical suggestions of even more exotic processes inside neutron stars, such as the formation of absolutely stable strange quark matter. In the latter event, neutron stars would be largely composed of strange quark matter possibly enveloped in a thin nuclear crust. This paper gives a brief overview of these striking physical possibilities with an emphasis on the role played by strangeness in neutron star matter, which constitutes compressed baryonic matter at ultra-high baryon number density but low temperature which is no accessible to relativistic heavy ion collision experiments.

Fridolin Weber; Alexander Ho; Rodrigo P. Negreiros; Philip Rosenfield

2006-04-20T23:59:59.000Z

410

Conditional sterility in plants  

DOE Patents [OSTI]

The present disclosure provides methods, recombinant DNA molecules, recombinant host cells containing the DNA molecules, and transgenic plant cells, plant tissue and plants which contain and express at least one antisense or interference RNA specific for a thiamine biosynthetic coding sequence or a thiamine binding protein or a thiamine-degrading protein, wherein the RNA or thiamine binding protein is expressed under the regulatory control of a transcription regulatory sequence which directs expression in male and/or female reproductive tissue. These transgenic plants are conditionally sterile; i.e., they are fertile only in the presence of exogenous thiamine. Such plants are especially appropriate for use in the seed industry or in the environment, for example, for use in revegetation of contaminated soils or phytoremediation, especially when those transgenic plants also contain and express one or more chimeric genes which confer resistance to contaminants.

Meagher, Richard B. (Athens, GA); McKinney, Elizabeth (Athens, GA); Kim, Tehryung (Taejeon, KR)

2010-02-23T23:59:59.000Z

411

Uncertainties in Gapped Graphene  

E-Print Network [OSTI]

Motivated by graphene-based quantum computer we examine the time-dependence of the position-momentum and position-velocity uncertainties in the monolayer gapped graphene. The effect of the energy gap to the uncertainties is shown to appear via the Compton-like wavelength $\\lambda_c$. The uncertainties in the graphene are mainly contributed by two phenomena, spreading and zitterbewegung. While the former determines the uncertainties in the long-range of time, the latter gives the highly oscillation to the uncertainties in the short-range of time. The uncertainties in the graphene are compared with the corresponding values for the usual free Hamiltonian $\\hat{H}_{free} = (p_1^2 + p_2^2) / 2 M$. It is shown that the uncertainties can be under control within the quantum mechanical law if one can choose the gap parameter $\\lambda_c$ freely.

Eylee Jung; Kwang S. Kim; DaeKil Park

2012-03-20T23:59:59.000Z

412

Coal in China  

SciTech Connect (OSTI)

The article gives an overview of the production and use of coal in China, for power generation and in other sectors. Coal use for power generation was 850 million tonnes in 2003 and 800 million tonnes in the non-power sector. The majority of power will continue to be produced from coal, with a trend towards new larger pulverised coal fired units and introduction of circulating fluidised bed combustors. Stricter regulations are forcing introduction of improved pollution control technologies. It seems likely that China will need international finance to supplement private and state investment to carry out a programme to develop and apply clean coal technologies. The author concludes that there is evidence of a market economy being established but there is a need to resolve inconsistencies with the planned aspects of the economy and that additional policies are needed in certain sectors to achieve sustainable development. 1 ref., 2 figs., 2 tabs.

Minchener, A.J. [IEA Clean Coal Centre, London (United Kingdom)

2005-07-01T23:59:59.000Z

413

Perturbations in a plasma  

E-Print Network [OSTI]

The perturbations of a homogeneous non-relativistic two-component plasma are studied in the Coulomb gauge. Starting from the solution found [2] of the equations of electromagnetic self consistency in a plasma [1], we add small perturbations to all quantities involved, and we enter the perturbed quantities in the equations, keeping only the first order terms in the perturbations. Because the unperturbed quantities are solutions of the equations, they cancel each other, and we are left with a set of 12 linear equations for the 12 perturbations (unknown quantities). Then we solve this set of linearized equations, in the approximation of small ratio of the masses of electrons over those of ions, and under the assumption that the plasma remains homogeneous.

Evangelos Chaliasos

2005-10-20T23:59:59.000Z

414

Energy balance in peridynamics.  

SciTech Connect (OSTI)

The peridynamic model of solid mechanics treats internal forces within a continuum through interactions across finite distances. These forces are determined through a constitutive model that, in the case of an elastic material, permits the strain energy density at a point to depend on the collective deformation of all the material within some finite distance of it. The forces between points are evaluated from the Frechet derivative of this strain energy density with respect to the deformation map. The resulting equation of motion is an integro-differential equation written in terms of these interparticle forces, rather than the traditional stress tensor field. Recent work on peridynamics has elucidated the energy balance in the presence of these long-range forces. We have derived the appropriate analogue of stress power, called absorbed power, that leads to a satisfactory definition of internal energy. This internal energy is additive, allowing us to meaningfully define an internal energy density field in the body. An expression for the local first law of thermodynamics within peridynamics combines this mechanical component, the absorbed power, with heat transport. The global statement of the energy balance over a subregion can be expressed in a form in which the mechanical and thermal terms contain only interactions between the interior of the subregion and the exterior, in a form anticipated by Noll in 1955. The local form of this first law within peridynamics, coupled with the second law as expressed in the Clausius-Duhem inequality, is amenable to the Coleman-Noll procedure for deriving restrictions on the constitutive model for thermomechanical response. Using an idea suggested by Fried in the context of systems of discrete particles, this procedure leads to a dissipation inequality for peridynamics that has a surprising form. It also leads to a thermodynamically consistent way to treat damage within the theory, shedding light on how damage, including the nucleation and advance of cracks, should be incorporated into a constitutive model.

Lehoucq, Richard B.; Silling, Stewart Andrew

2010-09-01T23:59:59.000Z

415

Effective contracts in supply chains  

E-Print Network [OSTI]

In the past decade, we have seen significant increase in the level of outsourcing in many industries. This increase in the level of outsourcing increases the importance of implementing effective contracts in supply chains. ...

Shum, Wanhang

2007-01-01T23:59:59.000Z

416

Introduction Transport in disordered graphene  

E-Print Network [OSTI]

Introduction Transport in disordered graphene Summary Ballistic transport in disordered graphene P, Gornyi, Mirlin Ballistic transport in disordered graphene #12;Introduction Transport in disordered graphene Summary Outline 1 Introduction Model Experimental motivation Transport in clean graphene 2

Fominov, Yakov

417

Neutron Reactions in Astrophysics  

E-Print Network [OSTI]

The quest for the origin of matter in the Universe had been the subject of philosophical and theological debates over the history of mankind, but quantitative answers could be found only by the scientific achievements of the last century. A first important step on this way was the development of spectral analysis by Kirchhoff and Bunsen in the middle of the 19$^{\\rm th}$ century, which provided first insight in the chemical composition of the sun and the stars. The energy source of the stars and the related processes of nucleosynthesis, however, could be revealed only with the discoveries of nuclear physics. A final breakthrough came eventually with the compilation of elemental and isotopic abundances in the solar system, which are reflecting the various nucleosynthetic processes in detail. This review is focusing on the mass region above iron, where the formation of the elements is dominated by neutron capture, mainly in the slow ($s$) and rapid ($r$) processes. Following a brief historic account and a sketch of the relevant astrophysical models, emphasis is put on the nuclear physics input, where status and perspectives of experimental approaches are presented in some detail, complemented by the indispensable role of theory.

R. Reifarth; C. Lederer; F. Kppeler

2014-03-22T23:59:59.000Z

418

Benford distributions in NMR  

E-Print Network [OSTI]

Benford's Law is an empirical law which predicts the frequency of significant digits in databases corresponding to various phenomena, natural or artificial. Although counter intuitive at the first sight, it predicts a higher occurrence of digit 1, and decreasing occurrences to other larger digits. Here we report the Benford analysis of various NMR databases and draw several interesting inferences. We observe that, in general, NMR signals follow Benford distribution in time-domain as well as in frequency domain. Our survey included NMR signals of various nuclear species in a wide variety of molecules in different phases, namely liquid, liquid-crystalline, and solid. We also studied the dependence of Benford distribution on NMR parameters such as signal to noise ratio, number of scans, pulse angles, and apodization. In this process we also find that, under certain circumstances, the Benford analysis can distinguish a genuine spectrum from a visually identical simulated spectrum. Further we find that chemical-shift databases and amplitudes of certain radio frequency pulses generated using optimal control techniques also satisfy Benford's law to a good extent.

Gaurav Bhole; Abhishek Shukla; T. S. Mahesh

2014-06-27T23:59:59.000Z

419

Gender determination in populus  

SciTech Connect (OSTI)

Gender, the expression of maleness or femaleness, in dioecious plants has been associated with changes in morphology, physiology, ecological position, and commercial importance of several species, including members of the Salicaceae family. Various mechanisms have been proposed to explain the expression of gender in Salicaceae, including sex chromosomes, simple Mendelian genes, quantitative genes, environment, and genotype-by-environment interactions. Published reports would favor a genetic basis for gender. The objective of this study was to identify molecular markers associated with gender in a segregating family of hybrid poplars. Bulked segregant analysis and chi-squared analysis were used to test for the occurrence of sex chromosomes, individual loci, and chromosome ratios (i.e., ploidy levels) as the mechanisms for gender determination. Examination of 2488 PCR based RAPD markers from 1219 primers revealed nine polymorphic bands between male and female bulked samples. However, linkage analysis indicated that none of these markers were significantly associated with gender. Chisquared results for difference in male-to-female ratios between diploid and triploid genotypes also revealed no significant differences. These findings suggest gender is not controlled via sex chromosomes, simple Mendelian loci or ratios of autosome to gender-determining loci. It is possible that gender is determined genetically by regions of the genome not sampled by the tested markers or by a complex of loci operating in an additive threshold manner or in an epistatic manner. It is also possible that gender is determined environmentally at an early zygote stage, canalizing gender expression.

McLetchie, D.N. [Univ. of Kentucky, Lexington, KY (United States). Dept. of Biological Sciences; Tuskan, G.A. [Oak Ridge National Lab., TN (United States)

1994-12-31T23:59:59.000Z

420

Secondary porosity in sandstones  

SciTech Connect (OSTI)

Secondary porosity in sandstones is caused by dissolution and fracturing, and is common in the sedimentary record. Secondary porosity commonly develops in the deep subsurface and thus provides an opportunity to extend exploration to depths traditionally considered unsuitable for exploration. Two contrasting routes of diagenesis exist in nature: porosity reduction and porosity enhancement. Porosity reduction is commonly caused by compaction and cementation, whereas porosity enhancement is primarily caused by dissolution of carbonate minerals. Two basic types of primary pores (intergranular and intragranular) and four basic types of secondary pores (grain fractures, rock fractures, intergranular, and intragranular) can be differentiated on the basis of (1) position of pores, (2) timing of origin, and (3) processes of origin. The proposed classification system is useful in inferring reservoir quality. Various types of secondary porosity are recognized using a comprehensive set of 20 criteria. The various criteria are based on manner of breakage, pore geometry, grain geometry, products of dissolution, and sediment packing. New evidence suggests that silicate minerals, including quartz, dissolve more commonly than have been reported. The abundant occurrence of secondary porosity in reservoir sandstones emphasizes the importance of secondary porosity in evaluating deep reservoirs.

Shanmugam, G.

1983-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "antiknock in dex" 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

Strangeness in Neutron Stars  

E-Print Network [OSTI]

It is generally agreed on that the tremendous densities reached in the centers of neutron stars provide a high-pressure environment in which numerous novel particles processes are likely to compete with each other. These processes range from the generation of hyperons to quark deconfinement to the formation of kaon condensates and H-matter. There are theoretical suggestions of even more exotic processes inside neutron stars, such as the formation of absolutely stable strange quark matter, a configuration of matter even more stable than the most stable atomic nucleus, iron. In the latter event, neutron stars would be largely composed of pure quark matter, eventually enveloped in a thin nuclear crust. No matter which physical processes are actually realized inside neutron stars, each one leads to fingerprints, some more pronounced than others though, in the observable stellar quantities. This feature combined with the unprecedented progress in observational astronomy, which allows us to see vistas with remarkable clarity that previously were only imagined, renders neutron stars to nearly ideal probes for a wide range of physical studies, including the role of strangeness in dense matter.

Fridolin Weber

2000-08-23T23:59:59.000Z

422

Chlorinated hydrocarbons in peat  

SciTech Connect (OSTI)

Concentrations (ng/g), accumulation rates (ug/m/sup 2/=yr) and burdens were determined for DDT (1,1,1-trichlorophenyl2-2'bis(p-chlorophenyl)ethane), polychlorinated biphenyls. Toxaphene, hexachlorobenzene (HCB) and a,b,g-hexachlorocyclohexanes (HCHs) in peat cores taken across the mid-latitudes of North America. Because peat bogs are ombrotrophic, thereby receiving all contaminant inputs from the atmosphere and because peat cores were dated, atmospheric input functions were constructed for all of the compounds listed above excepting the HCHs. Compound inventories (burdens) in peat cores of PCBs, HCB, HCHs, Toxaphene, DDT, Pb and Zn were compared, indicating a strong influence from areas proximate to industrial sources and the atmospheric transport from source regions. Untransformed parent DDT (p,p' and o,p'-DDT) in surface peat and in precipitation provides evidence for the long range transport of DDT from neighboring countries where use has increased over the past 10-15 years. Present accumulation rates of DDT in peat are about 10-20% of maximum levels associated with peak use in the US around 1960. The DDT input function that was developed can be used to date peat cores. Transformations of DDT and PCBs were also examined in peat cores. First order transformation rates of DDT (p,p' and o,p') to DDD in anaerobic peat core environments ranged from 0.03 to 0.09 yr/sup -1/ with differences related to temperature. Aerobic transformation of PCB congeners in peat cores and microcosms was rapid for 2,3 and several 4 chlorinated congeners (T/sub 1/2 less than or equal to 0.2 to 3 years) and declined with increasing chlorine number.

Rapaport, R.A.

1985-01-01T23:59:59.000Z

423

Chaos Models in Economics  

E-Print Network [OSTI]

The paper discusses the main ideas of the chaos theory and presents mainly the importance of the nonlinearities in the mathematical models. Chaos and order are apparently two opposite terms. The fact that in chaos can be found a certain precise symmetry (Feigenbaum numbers) is even more surprising. As an illustration of the ubiquity of chaos, three models among many other existing models that have chaotic features are presented here: the nonlinear feedback profit model, one model for the simulation of the exchange rate and one application of the chaos theory in the capital markets.

Sorin Vlad; Paul Pascu; Nicolae Morariu

2010-01-20T23:59:59.000Z

424

Revolution in Detection Affairs  

SciTech Connect (OSTI)

The detection of nuclear or radioactive materials for homeland or national security purposes is inherently difficult. This is one reason detection efforts must be seen as just one part of an overall nuclear defense strategy which includes, inter alia, material security, detection, interdiction, consequence management and recovery. Nevertheless, one could argue that there has been a revolution in detection affairs in the past several decades as the innovative application of new technology has changed the character and conduct of detection operations. This revolution will likely be most effectively reinforced in the coming decades with the networking of detectors and innovative application of anomaly detection algorithms.

Stern W.

2013-11-02T23:59:59.000Z

425

Technology in water conservation  

E-Print Network [OSTI]

be accomplished with instruments a#22;ached to pipelines at manholes. #27;ese devices ?listen? to the water #16;ow in the pipe; when they detect the characteristic sound of a leak, they report by radio to permanent or mobile collection points. Even a small... leak can be detected. Rainwater catchment may be a good way to replace water from other potable sources. In some situations, this involves using the simple technology of capturing rainfall runo#21; from a roof or another surface. In a hot, dry...

Finch, Dr. Calvin

2013-01-01T23:59:59.000Z

426

Food Adulteration in Texas.  

E-Print Network [OSTI]

proper provision for its enfolrcement, passage of the Federal Food Law. The time seems propitious for the 4 and which will, in co-operation with the Federal law, rfd the State of all adulterated or illegal food. The present Texas law is a good one... itself until the past summer. 3 Samples were then collected in Houston, Bryan, Waco, Dallas, Ft. Worth, and Clebiurne These samples were examined for adulteration or illegal additions, and the results are presented in the following tables. Table I...

Fraps, G. S. (George Stronach)

1906-01-01T23:59:59.000Z

427

Leptons in Composite MFV  

E-Print Network [OSTI]

We study the lepton sector of composite Higgs models with partial compositeness. The standard anarchic scenario is in conflict with the absence of observable charged lepton flavor violation. This tension can be completely solved in MFV scenarios that require either left-handed or right-handed SM leptons to be equally composite. Constraints on this scenario are weak and the composite lepton partners could be as light as few hundreds GeVs with interesting LHC signatures. The contribution to the muon (g-2) in theories where the Higgs is a pseudo Nambu-Goldstone boson is also discussed.

Michele Redi

2014-07-21T23:59:59.000Z

428

Electromagnetic Probes in PHENIX  

E-Print Network [OSTI]

Electromagnetic probes are arguably the most universal tools to study the different physics processes in high energy hadron and heavy ion collisions. In this paper we summarize recent measurements of real and virtual direct photons at central rapidity by the PHENIX experiment at RHIC in p+p, d+Au and Au+Au collisions. We also discuss the impact of the results and the constraints they put on theoretical models. At the end we report on the immediate as well as on the mid-term future of photon measurements at RHIC.

Gabor David

2006-09-21T23:59:59.000Z

429

Islands in the landscape  

E-Print Network [OSTI]

The string theory landscape consists of many metastable de Sitter vacua, populated by eternal inflation. Tunneling between these vacua gives rise to a dynamical system, which asymptotically settles down to an equilibrium state. We investigate the effects of sinks to anti-de Sitter space, and show how their existence can change probabilities in the landscape. Sinks can disturb the thermal occupation numbers that would otherwise exist in the landscape and may cause regions that were previously in thermal contact to be divided into separate, thermally isolated islands.

T. Clifton; Andrei Linde; Navin Sivanandam

2007-01-10T23:59:59.000Z

430

Polymers in a Vacuum  

SciTech Connect (OSTI)

In a variety of situations, isolated polymer molecules are found in a vacuum, and here we examine their properties. Angular momentum conservation is shown to significantly alter the average size of a chain and its conservation is only broken slowly by thermal radiation. For an ideal chain, the time autocorrelation for monomer position oscillates with a period proportional to chain length. The oscillations and damping are analyzed in detail. Short-range repulsive interactions suppress oscillations and speed up relaxation, but stretched chains still show damped oscillatory correlations.

Deutsch, J. M. [Department of Physics, University of California, Santa Cruz, California 95064 (United States)

2007-12-07T23:59:59.000Z

431

Integrity in Depth  

E-Print Network [OSTI]

to the common problem of colluding with the attitude that shame is something to be ashamed of. He agrees with Andrew Morrison that for any in dividual with major deficits of the self, shame, not rage, is the principal affect. Beebe advocates "a psychology... is "Working on Integrity." In its opening section, "Fidelity to Process," Beebe shares a poi gnant therapeutic interchange in which he makes a mistake that leads to the patient's being angry at him. This rage facilitates the patient's discovery of her own...

Beebe, John

1992-01-01T23:59:59.000Z

432

Buddist Architecture in India  

E-Print Network [OSTI]

sites like S"nchi and Taxila (Pakistan) have Euch fine Buddhist monuments, even though they were not visited by Buddha. The earliest Buddhist monuments in India are attributable to Asoka (273-32 B.C.) who exerted his eneigies and the resources of his... of Paharpur in Bangladesh and Borobudur in Java, both dating from circa A.D. 800. V3is3li (Di~trict Muzaffarpur), which was a favourite resort of Buddha and one of the eight holy places of Buddhism has an uninscribed Mauryan pillar, besides extensive...

Deva, Krishna

433

In Other News  

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 withconfinementEtching.348 270 300 219ImprovementsImprovingIn Other NewsInIn

434

In Other News  

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

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435

In Other News  

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 withconfinementEtching.348 270 300 219ImprovementsImprovingIn OtherInIn Other

436

In Other News  

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 withconfinementEtching.348 270 300 219ImprovementsImprovingIn OtherInIn

437

In other news  

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 withconfinementEtching.348 270 300Aptamers and GraphenePhaseNewsaIn otherInIn

438

In other news  

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 withconfinementEtching.348 270 300Aptamers and GraphenePhaseNewsaInIn otherIn

439

In other news  

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 withconfinementEtching.348 270 300Aptamers and GraphenePhaseNewsaInInIn other

440

In other news  

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 withconfinementEtching.348 270 300Aptamers and GraphenePhaseNewsaInInIn

Note: This page contains sample records for the topic "antiknock in dex" 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

In other news  

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 withconfinementEtching.348 270 300Aptamers andIn other news CommunityInIn

442

Magnetocaloric effect in manganites  

SciTech Connect (OSTI)

The magnetocaloric effect (MCE) in La{sub 1-x}Sr{sub x}MnO{sub 3}, Sm{sub 0.55}Sr{sub 0.45}MnO{sub 3}, and PrBaMn{sub 2}O{sub 6} compounds is studied. The maximum values of MCE ({Delta}T{sub max}) determined by a direct method in the second and third compositions and in La{sub 0.9}Sr{sub 0.1}MnO{sub 3} are found to be much lower than those calculated from the change of the magnetic part of entropy in the Curie temperature (T{sub C}) and the Neel temperature (T{sub N}) range. The negative contribution of the antiferromagnetic (AFM) part of a sample in the La{sub 1-x}Sr{sub x}MnO{sub 3} system at 0.1 {<=} x {<=} 0.3 decreases {Delta}T{sub max} and changes the {Delta}T(T) curve shape, shifting its maximum 20-40 K above T{sub C}. Lower values of {Delta}T{sub max} are detected in the range T{sub C} = 130-142 K in polycrystalline and single-crystal Sm{sub 0.55}Sr{sub 0.45}MnO{sub 3} samples cooled in air. If such samples were cooled in an oxygen atmosphere (which restores broken Mn-O-Mn bonds and, thus, increases the volume of CE-type AFM clusters), the maximum in the temperature dependence of MCE is located at T{sub N} (243 K) for CE-type AFM clusters. A magnetic field applied to a sample during the MCE measurements transforms these clusters into a ferromagnetic (FM) state, and both types of clusters decompose at T = T{sub N}. The PrBaMn{sub 2}O{sub 6} composition undergoes an AFM-FM transition at 231 K, and the temperature dependence of its MCE has a sharp minimum at T = 234 K, where MCE is negative, and a broad maximum covering T{sub C}. The absolute values of MCE at both extrema are several times lower than those calculated from the change in the magnetic entropy. These phenomena are explained by the presence of a magnetically heterogeneous FM-AFM state in these manganites.

Koroleva, L. I., E-mail: koroleva@phys.msu.ru; Zashchirinskii, D. M.; Morozov, A. S. [Moscow State University (Russian Federation); Szymczak, R. [Polish Academy of Sciences, Institute of Physics (Poland)

2012-10-15T23:59:59.000Z

443

Color in architecture  

E-Print Network [OSTI]

declared that red light stimulated the movement of blood& blue light soothed it, Amulets and gems have been recorded as having protective and healing power accordin, to color, Amulets were preferred in this orders red? blue, yellow, green, white... much is tiring, Slushy Slue is serene, passive, cool. Spaniards and Venetians of the elite classes recognized the aloof di;city of blue and black in clothingi In the church, blue ca-e to s-~bolize sincerity and hope, Still used are the expressions...

Vrooman, Richard

1952-01-01T23:59:59.000Z

444

Antiproton Absorption in Nuclei  

E-Print Network [OSTI]

We present the analysis of experimental data on forward antiproton production on nuclei. The calculations are done in the framework of a folding model which takes properly into account both incoherent direct proton-nucleon and cascade pion-nucleon antiproton production processes as well as internal nucleon momentum distribution. The effective antiproton-nucleon cross section in nuclear matter and the imaginary part of the antiproton nuclear optical potential are estimated to be 25-45 mb and -(38-56) MeV at normal nuclear matter density, respectively. The results of the performed analysis evidence for the decreasing of antiproton absorption in the nuclear medium.

Yu. T. Kiselev; E. Ya. Paryev

2006-01-24T23:59:59.000Z

445

Historical change in coral reef communities in Caribbean Panama  

E-Print Network [OSTI]

persistence interrupted in Caribbean coral reefs. EcologyJBC. Ecological change on Caribbean coral reefs before coraland extinctions in the Caribbean reef-coral fauna. In

Cramer, Katie Lynn

2011-01-01T23:59:59.000Z

446

Farming in a Changing Climate: Agricultural Adaptation in Canada  

E-Print Network [OSTI]

Agricultural Adaptation in Canada Ellen Wall, Barry Smit,Agricultural Adaptation in Canada. Vancouver, BC: Universitythe agri-food sector in Canada, the insights provided are so

Jain, Varinder

2010-01-01T23:59:59.000Z

447

A ROLE FOR MANGANESE IN OXYGEN EVOLUTION IN PHOTOSYNTHESIS  

E-Print Network [OSTI]

synthesis, Topics jn Photosynthesis, vol. 2, J. Barber,and J. R. Benemann, in Photosynthesis in Relation to ModelProcesses of Photosynthesis, Topics in Photosynthesis, vol.

Sauer, Kenneth

2012-01-01T23:59:59.000Z

448

Stakeholder Engagement in Climate Change Policymaking in American Cities  

E-Print Network [OSTI]

s population, local water policy Journal of Environmentalparticipate in conflicts over water in particular locations.level. In contrast, the water quality issue involves

Fiack, Duran; Kamieniecki , Sheldon

2015-01-01T23:59:59.000Z

449

Natural Oxidation of Black Carbon in Soils: Changes in Molecular...  

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

Carbon in Soils: Changes in Molecular Form and Surface Charge along a Climosequence. Abstract: The aim of this work was to investigate changes in molecular form and surface...

450

Essays in computational economics  

E-Print Network [OSTI]

The focus of my PhD research has been on the acquisition of computational modeling and simulation methods used in both theoretical and applied Economics. My first chapter provides an interactive review of finite-difference ...

Pugh, David

2014-07-02T23:59:59.000Z

451

Essays in Development Economics  

E-Print Network [OSTI]

Discontinuity Designs in Economics," Journal of EconomicJournal of Development Economics 87(1): 57-75. [21] Ozier,Journal of Development Economics 94, 151-163. [9] Delavande,

Keats, Anthony

2012-01-01T23:59:59.000Z

452

Three essays in finance  

E-Print Network [OSTI]

This thesis consists of three essays on asset pricing. Chapter 1 presents an equilibrium model to study the convergence trading of large hedge funds in segmented markets. The model provides an alternative explanation for ...

He, Li, 1977-

2006-01-01T23:59:59.000Z

453

Essays in capital markets  

E-Print Network [OSTI]

This thesis consists of three essays in capital markets. The first essay presents a dynamic asset pricing model with heterogeneously informed agents. Unlike previous research, the general case where differential information ...

Makarov, Igor, 1976-

2006-01-01T23:59:59.000Z

454

Suspensions in hydraulic fracturing  

SciTech Connect (OSTI)

Suspensions or slurries are widely used in well stimulation and hydraulic fracturing processes to enhance the production of oil and gas from the underground hydrocarbon-bearing formation. The success of these processes depends significantly upon having a thorough understanding of the behavior of suspensions used. Therefore, the characterization of suspensions under realistic conditions, for their rheological and hydraulic properties, is very important. This chapter deals with the state-of-the-art hydraulic fracturing suspension technology. Specifically it deals with various types of suspensions used in well stimulation and fracturing processes, their rheological characterization and hydraulic properties, behavior of suspensions in horizontal wells, review of proppant settling velocity and proppant transport in the fracture, and presently available measurement techniques for suspensions and their merits. Future industry needs for better understanding of the complex behavior of suspensions are also addressed. 74 refs., 21 figs., 1 tab.

Shah, S.N. [Univ. of Oklahoma, Norman, OK (United States)

1996-12-31T23:59:59.000Z

455

Essays in economics  

E-Print Network [OSTI]

In the first chapter, I explore the role of coordination problems and self-fulfilling beliefs as drivers of sovereign default risk. I employ global-game techniques to induce a unique equilibrium. Along the unique equilibrium, ...

Zabai, Anna

2014-01-01T23:59:59.000Z

456

Essays in political economy  

E-Print Network [OSTI]

This dissertation consists of three essays. The first chapter is an empirical investigation of social change, looking at the Prohibition Era in the U.S. It explores how the implementation of policies affects the evolution ...

Garca Jimeno, Camilo

2011-01-01T23:59:59.000Z

457

Essays in economics  

E-Print Network [OSTI]

The first chapter analyzes incentives and quality in hospitals with physician-investors. Proponents of physician ownership argue that it improves care; opponents claim that physician-investors "cherry-pick" profitable ...

Swanson, Ashley (Ashley Terese)

2012-01-01T23:59:59.000Z

458

Sustainability in architecture  

E-Print Network [OSTI]

Current standard practice in architecture does not take into account the external societal costs that a building creates. To understand the total consequences of a building, one must consider all of the ecological and human ...

Cordero, Elizabeth, 1959-

2001-01-01T23:59:59.000Z

459

Exotic in Leptonic Machines  

E-Print Network [OSTI]

Selected topics of exotics in leptonic machines are presented, including recent discovery of abnormal structures around the ppbar threshold and new information of the XYZ (charmonium-like) states.

Kai Zhu

2014-08-07T23:59:59.000Z

460

Feral Hogs in Texas  

E-Print Network [OSTI]

Feral hogs are found in almost parts of Texas. They are prized by hunters but despised by landowners who suffer from their damage. This publication is a comprehensive look at feral hogs, from their history and identification to their biology...

Mapston, Mark; Texas Wildlife Services

2007-03-19T23:59:59.000Z

Note: This page contains sample records for the topic "antiknock in dex" 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

Entertaining in a Hurry.  

E-Print Network [OSTI]

] Entertaining in a Hur~y Fr~ces L. Reasonover and Mary K. Sweeten* The employed homemaker often entertains friends, business associates, neighbors and relatives. Simple meals and refreshments provide delicious and appealing food for company and make...

Sweeten, Mary K.; Reasonover, Frances L.

1980-01-01T23:59:59.000Z

462

Crowdsourcing in community participatory planning in China : case studies in four communities in Shenzhen  

E-Print Network [OSTI]

Community participatory planning is a crucial component of urban planning but there is no effective public participation in the Chinese planning decision-making process, which brings up social conflicts and planning failures. ...

Zhang, Qianqian

2014-01-01T23:59:59.000Z

463

Generation gaps in engineering?  

E-Print Network [OSTI]

There is much enthusiastic debate on the topic of generation gaps in the workplace today; what the generational differences are, how to address the apparent challenges, and if the generations themselves are even real. ...

Kim, David J. (David Jinwoo)

2008-01-01T23:59:59.000Z

464

Inclusive Jets in PHP  

E-Print Network [OSTI]

Differential inclusive-jet cross sections have been measured in photoproduction for boson virtualities Q^2 < 1 GeV^2 with the ZEUS detector at HERA using an integrated luminosity of 300 pb^-1. Jets were identified in the laboratory frame using the k_T, anti-k_T or SIScone jet algorithms. Cross sections are presented as functions of the jet pseudorapidity, eta(jet), and the jet transverse energy, E_T(jet). Next-to-leading-order QCD calculations give a good description of the measurements, except for jets with low E_T(jet) and high eta(jet). The cross sections have the potential to improve the determination of the PDFs in future QCD fits. Values of alpha_s(M_Z) have been extracted from the measurements based on different jet algorithms. In addition, the energy-scale dependence of the strong coupling was determined.

Roloff, Philipp

2013-01-01T23:59:59.000Z

465

Inclusive Jets in PHP  

E-Print Network [OSTI]

Differential inclusive-jet cross sections have been measured in photoproduction for boson virtualities Q^2 < 1 GeV^2 with the ZEUS detector at HERA using an integrated luminosity of 300 pb^-1. Jets were identified in the laboratory frame using the k_T, anti-k_T or SIScone jet algorithms. Cross sections are presented as functions of the jet pseudorapidity, eta(jet), and the jet transverse energy, E_T(jet). Next-to-leading-order QCD calculations give a good description of the measurements, except for jets with low E_T(jet) and high eta(jet). The cross sections have the potential to improve the determination of the PDFs in future QCD fits. Values of alpha_s(M_Z) have been extracted from the measurements based on different jet algorithms. In addition, the energy-scale dependence of the strong coupling was determined.

Philipp Roloff

2013-10-23T23:59:59.000Z

466

Administrative morality in Colombia  

E-Print Network [OSTI]

This dissertation analyzes a cause of action created by the Colombian constitutional reform of 1991: administrative morality. This cause of action was created with the purpose of facilitating citizen engagement in governmental ...

Paez Murcia, Angela Maria

2013-05-31T23:59:59.000Z

467

Walkability Planning in Jakarta  

E-Print Network [OSTI]

Rukmana, Deden. Street Vendors and Planning in IndonesianYatmo, Yandi Andri. Street Vendors as 'Out of Place' UrbanYatmo, Yandi Andri. Street Vendors as 'Out of Place' Urban

Lo, Ria S. Hutabarat

2011-01-01T23:59:59.000Z

468

Imaging in radiotherapy  

SciTech Connect (OSTI)

The text contains details of recording media, image quality, sensitometry, processing and equipment used in radiotherapy for imaging. It reflects part of the syllabus for the College of Radiographers.

Taylor, J.

1987-01-01T23:59:59.000Z

469

Duality in linearized gravity  

SciTech Connect (OSTI)

We show that duality transformations of linearized gravity in four dimensions, i.e., rotations of the linearized Riemann tensor and its dual into each other, can be extended to the dynamical fields of the theory so as to be symmetries of the action and not just symmetries of the equations of motion. Our approach relies on the introduction of two superpotentials, one for the spatial components of the spin-2 field and the other for their canonically conjugate momenta. These superpotentials are two-index, symmetric tensors. They can be taken to be the basic dynamical fields and appear locally in the action. They are simply rotated into each other under duality. In terms of the superpotentials, the canonical generator of duality rotations is found to have a Chern-Simons-like structure, as in the Maxwell case.

Henneaux, Marc; Teitelboim, Claudio [Physique Theorique et Mathematique and International Solvay Institutes, Universite Libre de Bruxelles, Campus Plaine C. P. 231, B-1050 Brussels (Belgium) and Centro de Estudios Cientificos (CECS), Valdivia (Chile); Centro de Estudios Cientificos (CECS), Valdivia (Chile)

2005-01-15T23:59:59.000Z

470

(Photosynthesis in intact plants)  

SciTech Connect (OSTI)

Progress in the two years since the last renewal application has been excellent. We have made substantial contributions on both main fronts of the projects, and are particularly happy with the progress of our research on intact plants. The approach of basing our field work on a sound foundation of laboratory studies has enabled is to use methods which provide unambiguous assays of well characterized reactions. We have also made excellent progress in several laboratory studies which will have direct applications in future field work, and have introduced to the laboratory a range of molecular genetics techniques which will allow us to explore new options in the attempt to understand function at the level of molecular structure.

Not Available

1990-01-01T23:59:59.000Z

471

Particles in complex fluids  

E-Print Network [OSTI]

This thesis describes experimental studies of colloidal particles dispersed in solvents which themselves have phase transitions. One common definition of soft matter is: a material characterized by a mesoscopic length ...

Zand, Danille D. van t

2010-01-01T23:59:59.000Z

472

Coupling in the Tevatron  

SciTech Connect (OSTI)

The performance of the Fermilab Tevatron Collider at the commencement of run Ib was far below expectations. After a frustrating period of several months, a low-{beta} quad downstream of the interaction point at B0 was found to be rolled. This rolled quadrupole coupled the horizontal and vertical motion of the Tevatron beams. It also made matching the beam from the Main Ring to the Tevatron impossible, resulting in emittance blow up on injection. The net result of the roll was a significant reduction in the Tevatron luminosity. When the roll in the quadrupole was corrected the performance of the Tevatron improved dramatically. This note will discuss the experimental data indicating the presence of coupling and subsequent calculations which show how coupling an affect the luminosity. It is not intended to exhaust a discussion of coupling, which hopefully will be understood well enough to be discussed in a subsequent note.

Gelfand, N.M.

1994-12-01T23:59:59.000Z

473

Crack coalescence in granite  

E-Print Network [OSTI]

This thesis experimentally investigates crack coalescence in prismatic Barre Granite specimens with two pre-cut, open flaws under uniaxial compression. Using a high-speed video system, crack initiation, propagation, and ...

Miller, James Thomas, Ph. D. Massachusetts Institute of Technology

2008-01-01T23:59:59.000Z

474

Essays in financial economics  

E-Print Network [OSTI]

In Chapter 1, we seek to understand the relation between liquidity and market imperfections from two dimensions: 1) Across liquidity measures, we compare the influence of imperfections on two commonly used measures, Kyle's ...

Zhou, Yifan, Ph. D. Massachusetts Institute of Technology

2013-01-01T23:59:59.000Z

475

Social networking in vehicles  

E-Print Network [OSTI]

In-vehicle, location-aware, socially aware telematic systems, known as Flossers, stand to revolutionize vehicles, and how their drivers interact with their physical and social worlds. With Flossers, users can broadcast and ...

Liang, Philip Angus

2006-01-01T23:59:59.000Z

476

Resources for research in  

E-Print Network [OSTI]

2006, went smoothly. Meanwhile, the first phase of the information systems master plan (2002, in Montpellier, completion of work on the transgenic greenhouses and construction of a plant biology building

477

Data Assimilation in Geosciences  

E-Print Network [OSTI]

Data Assimilation in Geosciences: A highly multidisciplinary enterprise Adrian Sandu Computational Science Laboratory Department of Computer Science Virginia Tech #12;Data assimilation fuses information kinetics Aerosols Model Transport Meteorology Emissions Observations Data Assimilation Targeted Observ

478

Essays in macroeconomics  

E-Print Network [OSTI]

This thesis examines questions in macroeconomics motivated by the 2007-2008 financial crisis and its aftermath. Chapter 1 studies the impact of a housing bust on regional labor reallocation and the labor market. I document ...

Nenov, Plamen T. (Plamen Toshkov)

2012-01-01T23:59:59.000Z

479

Optimal traps in graphene  

E-Print Network [OSTI]

We transform the two-dimensional Dirac-Weyl equation, which governs the charge carriers in graphene, into a non-linear first-order differential equation for scattering phase shift, using the so-called variable phase method. This allows us to utilize the Levinson Theorem to find zero-energy bound states created electrostatically in realistic structures. These confined states are formed at critical potential strengths, which leads to us posit the use of `optimal traps' to combat the chiral tunneling found in graphene, which could be explored experimentally with an artificial network of point charges held above the graphene layer. We also discuss scattering on these states and find the zero angular momentum states create a dominant peak in scattering cross-section as energy tends towards the Dirac point energy, suggesting a dominant contribution to resistivity.

C. A. Downing; A. R. Pearce; R. J. Churchill; M. E. Portnoi

2015-03-27T23:59:59.000Z

480

ARTICLE IN PRESS Automatica ( )  

E-Print Network [OSTI]

antee "large" regions of attraction (Sontag & Sussmann, 1990; Teel, 1992; Lin & Saberi, 1993; Megretski discussed in the same context: the highlow gain philosophy of Saberi, Lin and Teel (1996), which explicitly

Bastin, Georges

Note: This page contains sample records for the topic "antiknock in dex" 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.


481

Understanding meaningfulness in videogames  

E-Print Network [OSTI]

This thesis explores "meaningfulness" in videogames. Academics, journalists, and others who write about games often discuss the concept of meaning yet seldom define it clearly. I am focusing on a variation of this topic: ...

Weise, Matthew Jason

2008-01-01T23:59:59.000Z

482

Carbon in detonations  

SciTech Connect (OSTI)

We review three principal results from a five year study of carbon and its properties in detonations and discuss the implications of these results to the behavior of explosives. We first present a new determination of the carbon melt line from release wave velocity measurements in the shocked state. We then outline a colloidal theory of carbon clustering which from diffusion limited coagulation predicts a slow energy release rate for the carbon chemistry. Finally, we show the results from the examination of recovered soot. Here we see support for the colloid theory and find the diamond phase of carbon. The main theme of this paper is that the carbon in detonation products is in the form of a colloidal suspension of carbon clusters which grow through diffusion limited collisions. Even the final state is not bulk graphite or diamond, but is a collection of small, less than 100 /angstrom/A, diamond and graphitic clusters. 23 refs., 4 figs.

Johnson, J.D.

1989-01-01T23:59:59.000Z

483

Essays in Applied Microeconomics  

E-Print Network [OSTI]

power plants in the generation of electricity. Therefore, itelectricity generation by highly polluting firms: the conventional fossil- fuel power plants.electricity generation by highly polluting firms: the conventional fossil-fuel power plants

Severnini, Edson Roberto

2013-01-01T23:59:59.000Z

484

International Programs in Agriculture  

E-Print Network [OSTI]

have any questions or comments. Jess Lowenberg-DeBoer Associate Dean and Director of International husband Luc and son Léonce, moved to Kansas for their new venture in farming; and to Corey Kujawa who left

485

Essays in microeconomics  

E-Print Network [OSTI]

This dissertation consists of three essays in microeconomic theory. The first two concern methods of modeling bounded rationality and unawareness, while the third applies a model of jointly determined reputation to incentive ...

Brczi, Nathan

2007-01-01T23:59:59.000Z

486

Experiments in service learning  

E-Print Network [OSTI]

Service learning, an educational method that involves the application of academic work to projects that benefit under-served communities, was explored in two complementary forms. First, the development of an alternative ...

Banzaert, Amy, 1976-

2006-01-01T23:59:59.000Z