9 Matching Results

Search Results

Advanced search parameters have been applied.

Waste site characterization through digital analysis of historical aerial photographs at Los Alamos National Laboratory and Eglin Air Force Base

Description: Historical aerial photographs are used to provide a physical history and preliminary mapping information for characterizing hazardous waste sites at Los Alamos National Laboratory and Eglin Air Force Base. The examples cited show how imagery was used to accurately locate and identify previous activities at a site, monitor changes that occurred over time, and document the observable of such activities today. The methodology demonstrates how historical imagery (along with any other pertinent data) can be used in the characterization of past environmental damage.
Date: May 1, 1995
Creator: Van Eeckhout, E.; Pope, P.; Wells, B.; Rofer, C. & Martin, B.
Partner: UNT Libraries Government Documents Department

Tobacco Curing

Description: "There are three essentially different ways of carrying out the curing [of tobacco]. These are (1) air curing, in which little or no artificial heat is applied; (2) flue curing, in which the tobacco is entirely cured by artificial heat and in such way as to prevent smoke from coming in contact with the leaf; and (3) fire curing, in which the tobacco is largely cured by artificial heat applied by means of open fires made on the floor of the barn, thus allowing smoke to come in contact with the leaf. It will be necessary to consider separately each of these methods, together with the modifications made in them in curing the various types of tobacco." -- p. 4
Date: 1913
Creator: Garner, W. W. (Wightman Wells), b. 1875
Partner: UNT Libraries Government Documents Department

Tobacco Culture

Description: "The methods for the production of the various types [of tobacco] briefly outlined in the present bulletin, though possibly susceptible of improvement in some of the details are the best that can be recommended in view of the present knowledge and experience of investigators and the more successful growers." -- title page.
Date: 1914
Creator: Garner, W. W. (Wightman Wells), b. 1875
Partner: UNT Libraries Government Documents Department

Environmental waste site characterization utilizing aerial photographs and satellite imagery: Three sites in New Mexico, USA

Description: The proper handling and characterization of past hazardous waste sites is becoming more and more important as world population extends into areas previously deemed undesirable. Historical photographs, past records, current aerial satellite imagery can play an important role in characterizing these sites. These data provide clear insight into defining problem areas which can be surface samples for further detail. Three such areas are discussed in this paper: (1) nuclear wastes buried in trenches at Los Alamos National Laboratory, (2) surface dumping at one site at Los Alamos National Laboratory, and (3) the historical development of a municipal landfill near Las Cruces, New Mexico.
Date: April 1, 1996
Creator: Van Eeckhout, E.; Pope, P.; Becker, N.; Wells, B.; Lewis, A. & David, N.
Partner: UNT Libraries Government Documents Department


Description: High resolution angle-resolved photoemission spectroscopy of highly overdoped Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} with a T{sub c} = 51K indicates that the basic transport processes in this material are fundamentally different from both the lesser doped cuprates as well as model metallic compounds. The overdoped sample has sharp ARPES peaks at the Fermi energy throughout the Brillouin zone even in the normal state, unlike the lesser-doped compounds. In particular, the spectra near ({pi},0) point show the presence of a sharp peak well above T{sub c}. The ARPES lineshapes, and thus the self energy, at a given energy are almost independent of k. Further, the quasiparticle scattering rate at the Fermi energy seems to be closely tied to direct resistivity measurements. This leads us to the conclusion that overdoped Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} is best described as a quasiparticle liquid. However, the energy dependence of the scattering rates is quite similar to that found in the lesser-doped compounds and quite different from that seen in a typical metal.
Date: July 23, 2001
Partner: UNT Libraries Government Documents Department

Phase separation and staging behavior in La{sub 2}CuO{sub 4+{delta}}

Description: Neutron scattering and magnetization measurements have been performed on three single crystals of La{sub 2}CuO{sub 4+{delta}}. For two crystals with {delta}{approx}0.02 and 0.03 phase separation of the intercalated oxygen occurs below 280 K whereas stage ordering occurs below 255 K. A third crystal exhibits no phase separation and a higher stage ordering temperature. All three show evidence for an in- plane ordering around 210 K. We propose a phase diagram which summarizes our observations.
Date: June 1996
Creator: Birgeneau, R. J.; Chou, F. C.; Kastner, M. A.; Lee, Y. S.; Wells, B. O.; Endoh, Y. et al.
Partner: UNT Libraries Government Documents Department

Spectral weight changes at the superconducting transition of Bi sub 2 Sr sub 2 CaCu sub 2 O sub 8+. delta

Description: An overview of our gap studies in high-{Tc} superconductors is presented for the workshop on Fermiology of high-{Tc}'s. The work is centered on the study of single crystal Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}}. In a conventional BCS superconductor, a superconducting gap {Delta} is formed when the near Fermi edge electrons condense to form Cooper pairs at low temperatures. As the material goes superconducting the density of states is modified such that the spectral intensity in the region from the Fermi energy down to an energy {Delta} is transferred to a regions just below {Delta}. While this spectral weight transfer has in the past been studied with tunneling spectroscopy, the size of the gap as well as improvements in our instrument resolution allow us now to study it with photoelectron spectroscopy. We have found that as the sample goes superconducting, not only is there spectral weight transfer from the gap region as in BCS theory, but along the {Gamma}-M direction there is also some spectral weight transfer from higher binding energies resulting in a dspectral dip at about {minus}90 meV relative E{sub F}. The total spectral weight decreases along the {Gamma}-M direction, but actually increases along the {Gamma}-X direction. This temperature dependent spectral transfer is discussed in terms of (1) a two to three dimensional phase transition from RVB theory; (2) a manifestation of the electron-boson interaction in the form of {alpha}{sup 2}F oscillations; and (3) conformity with the theory of Van Hove singularities. The latter are particularly attractive in that there are several other observations possibly explained by them: (1) the observation that the magnitude of the gap is anisotropic in the a-b plane; (2) the observation that for overdoped samples the magnitude of D appears to fall off faster then {Tc}. 25 refs., 8 figs., 1 tab.
Date: January 1, 1991
Creator: Dessau, D.S.; Shen, Z.X.; Wells, B.O.; Spicer, W.E. (Stanford Univ., CA (United States). Stanford Electronics Labs.) & Arko, A.J. (Los Alamos National Lab., NM (United States))
Partner: UNT Libraries Government Documents Department

Electronic structure of monoclinic BaBiO sub 3

Description: We present the results of photoemission studies of valence disordered'' monoclinic BaBiO{sub 3} in the photon energy range 15--120 eV. The line-shapes of the valence band photoemission spectra and the Ba contributions to the valence band are very similar to the line shapes of the total density of states and Ba partial density of states, respectively. Oxygen resonance is observed, demonstrating the existence of empty O 2p states. These results support a more covalent rather than a simple ionic picture for the electronic states of BaBiO{sub 3}. 10 refs., 2 figs.
Date: January 1, 1989
Creator: Shen, Z.X.; Lindberg, P.A.P.; Wells, B.O.; Dessau, D.S.; Borg, A.; Lindau, I. et al.
Partner: UNT Libraries Government Documents Department