2,810 Matching Results

Search Results

Advanced search parameters have been applied.

Effect on Sediment Yield and Water Quality of a Nonrehabilitated Surface Coal Mine in North-Central Wyoming

Description: From introduction: The purpose of this study was to determine the magnitude of some effects of an abandoned surface coal mine on the hydrologic environment. Specific objectives were (1) to define areas of erosion and deposition; (2) to determine if the sediment yield from an undisturbed drainage basin was less than that from a drainage basin partly disturbed by mining activity; and (3) to determine if there were differences in chemical composition of hillslope materials, sediment, and pond water in the two basins.
Date: March 1979
Creator: Ringen, Bruce H.; Shown, Lynn M.; Hadley, Richard F. & Hinkley, Todd K.
Partner: UNT Libraries Government Documents Department


Description: Torrefaction tests were carried out on miscanthus samples in order to understand the changes in chemical composition at temperatures of 250–350°C and residence times of 30–120 minutes. The raw material chemical composition was moisture content 7.97%, moisture-free carbon (C) 47.73%, hydrogen (H) 5.85%, nitrogen (N) 0.28%, sulphur (S) 0.02%, volatiles (V) 83.29% for volatiles, and moisture and ash-free (MAF) calorific value (CV) 8423 BTU/lb (19.59 MJ/kg). Torrefaction at temperatures of 250°C and residence time of 30 minutes resulted in a significant decrease in moisture by about 82.68%, but the other components, C, H, N, S, and V changed only marginally. Increasing the torrefaction temperature to 350°C and residence time to 120 minutes further reduced the moisture to a final value of 0.54% (a 93.2% reduction compared to original) and also resulted in a significant decrease in the other components, H, N, and V by 58.29%, 14.28%, and 70.45%, respectively. The carbon content at 350°C and 120 minutes increased by about 4% and sulfur values were below detection limits. The calorific values increased by about 5.59% at 250°C and 30 minutes, whereas at 350°C and 120 minutes, the increase was much greater (about 75.61%) and resulted in a maximum degree of carbonization of 1.60. The H/C ratio decreased with an increase in torrefaction temperature, where a minimum value of 0.6 was observed at 350°C and 120 minutes. The regression equations developed with respect to torrefaction temperature and times have adequately described the changes in chemical composition. The surface plots developed based on the regression equations indicate that torrefaction temperatures of 300–350°C and residence times of 30–120 minutes residence time can help to increase carbon content, calorific value, and degree of carbonization to > 49.4%, >11,990 BTU/lb (27 MJ/kg), and 1.4, and reduce moisture, nitrogen, volatile, and the H/C ratio to 0.525–0.725, ...
Date: November 1, 2001
Creator: Tumuluru, Jaya Shankar; Boardman, Richard; Wright, Christopher & Heintzelman, John
Partner: UNT Libraries Government Documents Department

Delineating the major KREEP-bearing terranes on the moon with global measurements of absolute thorium abundances

Description: The Lunar Prospector (LP) Gamma-Ray Spectrometer (GRS) has been used to map the global composition of thorium on the lunar surface. Previous LP results of relative thorium abundances demonstrated that thorium is highly concentrated in and around the nearside western maria and less so in the South Pole Aitken (SPA) basin. Using new detector modeling results and a larger data set, the authors present here a global map of absolute thorium abundances on a 2{degree} by 2{degree} equal-area pixel scale. Because thorium is a tracer of KREEP-rich material, these data provide fundamental information regarding the locations and importance of terranes that are rich in KREEP bearing materials.
Date: March 1, 1999
Creator: Lawrence, D.J.; Feldman, W.C.; Barraclough, B.L.; Elphic, R.C.; Prettyman, T.H.; Binder, A.B. et al.
Partner: UNT Libraries Government Documents Department

Effect on Performance of Composition of Li-Ion Carbon Anodes Derived from PMAN/DVB Copolymers

Description: The effects on electrochemical performance of the nitrogen content of disordered carbons derived from polymethacryonitrile (PMAN)-divinylbenzene (DVB) copolymers were examined in galvanostatic cycling tests between 2 V and 0.01 V vs. Li/Li+ in lM LiPF<sub>6</sub>/ethylene carbonate (EC)-dimethyl carbonate (DMC). The first-cycle reversible capacities and coulombic efficiencies increased with increase in the level of nitrogen for samples prepared at 700&deg;C. However, the degree of fade also increased. Similar tests were performed on materials that were additionally heated at 1,000&deg; and 1,300&deg;C for five hours. Loss of nitrogen, oxygen, and hydrogen occurred under these conditions, with none remaining at the highest temperature in all cases but one. The pyrolysis temperature dominated the electrochemical performance for these samples, with lower reversible and irreversible capacities for the first intercalation cycle as the pyrolysis temperature was increased. Fade was reduced and coulombic efficiencies also improved with increase in temperate. The large irreversible capacities and high fade of these materials makes them unsuitable for use in Li-ion cells.
Date: May 14, 1999
Creator: Even, William R. & Guidotti, Ronald A.
Partner: UNT Libraries Government Documents Department

History of ultrahigh carbon steels

Description: The history and development of ultrahigh carbon steels (i.e., steels containing between 1 and 2.l percent C and now known as UHCS) are described. The early use of steel compositions containing carbon contents above the eutectoid level is found in ancient weapons from around the world. For example, both Damascus and Japanese sword steels are hypereutectoid steels. Their manufacture and processing is of interest in understanding the role of carbon content in the development of modern steels. Although sporadic examples of UHCS compositions are found in steels examined in the early part of this century, it was not until the mid-1970s that the modern study began. This study had its origin in the development of superplastic behavior in steels and the recognition that increasing the carbon content was of importance in developing that property. The compositions that were optimal for superplasticity involved the development of steels that contained higher carbon contents than conventional modern steels. It was discovered, however, that the room temperature properties of these compositions were of interest in their own right. Following this discovery, a period of intense work began on understanding their manufacture, processing, and properties for both superplastic forming and room temperature applications. The development of superplastic cast irons and iron carbides, as well as those of laminated composites containing UHCS, was an important part of this history.
Date: June 20, 1997
Creator: Wadsworth, J. & Sherby, O.D.
Partner: UNT Libraries Government Documents Department

Industrial Alcohol: Sources and Manufacture

Description: Report discussing the production and manufacturing process of denatured (or industrial) alcohol in the United States. Topics discussed include laws and regulations, materials from which alcohol can be produced, and the steps of the manufacturing process.
Date: 1911
Creator: Sawyer, H. E.
Partner: UNT Libraries Government Documents Department

Lower Saccharide Nanometric Materials and Methods

Description: A ceramic composition having at least one nanometric ceramic powder, at least one lower saccharide, and water. The composition is useful in many industrial applications, including preparation of stronger and substantially defect free green and sintered ceramic bodies.
Date: July 13, 2004
Creator: Schilling, Christopher H.; Tomasik, Piotr & Sikora, Marek
Partner: UNT Libraries Government Documents Department

Correlation between Crystallographic and Magnetic Domains at Co/NiO(001) Interfaces

Description: Using soft x-ray spectromicroscopy we show that NiO(001) exhibits a crystallographic and magnetic domain structure near the surface identical to that of the bulk. Upon Co deposition a perpendicular coupling between the Ni and Co moments is observed that persists even after formation of uncompensated Ni spins at the interface through annealing. The chemical composition at the interface alters its crystallographic structure and leads to a reorientation of the Ni moments from the &lt;112&gt; to the &lt;110&gt; direction. We show that this reorientation is driven by changes in the magnetocrystalline anisotropy rather than exchange coupling mediated by residual uncompensated spins.
Date: December 18, 2008
Creator: Ohldag, H.; van der Laan, G. & Arenholz, E.
Partner: UNT Libraries Government Documents Department

Composition of the essential oils from Rocky Mountain juniper (Juniperus scopulorum), Big sagebrush (Artemisia tridentata), and White Sage (Salvia apiana).

Description: The essential oils of Juniperus scopulorum, Artemisia tridentata, and Salvia apiana obtained by steam extraction were analyzed by GC-MS and GC-FID. For J. scopulorum, twenty-five compounds were identified which accounts for 92.43% of the oil. The primary constituents were sabinene (49.91%), {alpha}-terpinene (9.95%), and 4-terpineol (6.79%). For A. tridentata, twenty compounds were identified which accounts for 84.32% of the oil. The primary constituents were camphor (28.63%), camphene (16.88%), and 1,8-cineole (13.23%). For S. apiana, fourteen compounds were identified which accounts for 96.76% of the oil. The primary component was 1,8-cineole (60.65%).
Date: September 1, 2003
Creator: Hochrein, James Michael; Irwin, Adriane Nadine & Borek, Theodore Thaddeus III
Partner: UNT Libraries Government Documents Department

Composition Analysis by Scanned Femtosecond Laser Ultraprobing (CASFLU/DOCMT)

Description: A new technology for ultrahigh-spatial resolution mapping of the isotopic, molecular, and chemical compositions of complex, multi-dimensional objects, in semiconductor, archaeological, paleontological, biological and materials R&amp;D.
Date: February 26, 2001
Creator: Ishikawa, M Y; Armstrong, J P; Stuart, B C; Wood, L L & Wynne, A E
Partner: UNT Libraries Government Documents Department

Influence of sample composition on aerosol organic and black carbon determinations

Description: In this paper we present results on characterization of filter-collected redwood (Sequoia sempevirens)-needle and eucalyptus smoke particles by thermal, optical, and solvent extraction methods. Our results demonstrate that organic and black carbon concentrations determined by thermal and optical methods are not only method dependent, but also critically influenced by the overall chemical composition of the samples. These conclusions are supported by the following: (1) the organic fraction of biomass smoke particles analyzed includes a component, ranging in concentration from about 6-20% of total carbon or from 16-30% of organic carbon, that is relatively non-volatile and has a combustion temperature close to that of black carbon; (2) presence of K or Na in biomass smoke samples lowers the combustion temperatures of this organic component and of black carbon, making their combustion properties indistinguishable; (3) about 20% of total organic material is nonvolatile when heated to 550{degrees}C in an inert atmosphere. Consequently, thermal methods that rely on a specific temperature to separate organic from black carbon may either underestimate or overestimate the black and organic carbon concentrations, depending on the amounts of Na and K and on the composition and concentration of organic material present in a sample. These analytical uncertainties and, under some conditions, absorption by organic material may contribute to the variability of empirically derived proportionality between light transmission through filter deposits and black carbon concentrations.
Date: July 1, 1995
Creator: Novakov, T. & Corrigan, C.E.
Partner: UNT Libraries Government Documents Department

Tank 241-Z-361 process and characterization history

Description: An Unreviewed Safety Question (Wagoner, 1997) was declared based on lack of adequate authorization basis for Tank 241-Z-361 in the 200W Area at Hanford. This document is a summary of the history of Tank 241-Z-361 through December 1997. Documents reviewed include engineering files, laboratory notebooks from characterization efforts, waste facility process procedures, supporting documents and interviews of people`s recollections of over twenty years ago. Records of transfers into the tank, past characterization efforts, and speculation were used to estimate the current condition of Tank 241-Z-361 and its contents. Information about the overall waste system as related to the settling tank was included to help in understanding the numbering system and process relationships. The Plutonium Finishing Plant was built in 1948 and began processing plutonium in mid-1949. The Incinerator (232-Z) operated from December 1961 until May 1973. The Plutonium Reclamation Facility (PRF, 236-Z) began operation in May 1964. The Waste Treatment Facility (242-Z) operated from August 1964 until August 1976. Waste from some processes went through transfer lines to 241-Z sump tanks. High salt and organic waste under normal operation were sent to Z-9 or Z-18 cribs. Water from the retention basin may have also passed through this tank. The transfer lines to 241-Z were numbered D-4 to D-6. The 241-Z sump tanks were numbered D-4 through D-8. The D-4, 5, and 8 drains went to the D-6 sump tank. When D-6 tank was full it was transferred to D-7 tank. Prior to transfer to cribs, the D-7 tank contents was sampled. If the plutonium content was analyzed to be more than 10 g per batch, the material was (generally) reprocessed. Below the discard limit, caustic was added and the material was sent to the cribs via the 241-Z-361 settling tank where solids settled out and the liquid overflowed by gravity ...
Date: August 6, 1998
Creator: Jones, S.A.
Partner: UNT Libraries Government Documents Department

Microstructure of compositionally modulated InAlAs

Description: The authors have observed spontaneous, lateral composition modulation in tensile InAlAs alloy films grown as short-period superlattices on InP (001). They have analyzed these films using transmission electron microscopy, x-ray reciprocal space mapping, and polarized photoluminescence spectroscopy. They find the growth front is nonplanar, exhibiting {approximately} 2 nm deep cusps aligned with the In-rich regions of the compositionally modulated films. In addition to the measured 15 nm wavelength modulation in the [110] direction, a modulation of 30 nm wavelength is seen in the orthogonal [1{bar 1}0] direction. The photoluminescence from the modulated layer is strongly polarized and red shifted by 0.22 eV.
Date: December 31, 1996
Creator: Twesten, R.D.; Millunchick, J.M.; Lee, S.R.; Follstaedt, D.M.; Jones, E.D.; Ahrenkiel, S.P. et al.
Partner: UNT Libraries Government Documents Department

Nano-patterning of Co/Pt multilayers.

Description: One of the most promising new systems for both basic research and technical development are the periodic arrays of nano-magnetic elements, as shown. Such arrays show remarkably rich and novel magnetic behavior. Periodic magnetic arrays not only provide excellent opportunities for new science but also constitute a promising candidate for new applications such as high-density, patterned magnetic memory for advanced computer designs in the next decade. In the presentation they will focus on patterned [Co4 {angstrom}/Pt10 {angstrom}]n multilayers, which demonstrate an unusually strong out-of-plane magnetic anisotropy and sensitivity to structural modification. This strong out-of-plane anisotropy makes Co/Pt ML the favorite candidates for perpendicular magnetic recording. The patterned Co/Pt ML are representatives of a new generation of magnetic nanostructures with lateral dimensions in 100 nm range, and individual layer thickness approaching a monolayer scale (e.g., 4 {angstrom} of Co and 10 {angstrom} of Pt). In addition to traditional lithography, they are developing a new approach to tailoring the local magnetic properties of Co/Pt ML. In this process the local magnetic properties are modified not through conventional modulation of the chemical composition, but through structural modification induced by low energy ion implantation.
Date: July 24, 2001
Creator: Metlushko, V.; Crabtree, G.; Welp, U.; Vlasko-Vlasov, V.; Baldo, P.; Rehn, L. E. et al.
Partner: UNT Libraries Government Documents Department

Commercial Fertilizers 1994

Description: This document presents a compilation of annual data about fertilizer use in the USA, including statistics about various kinds of fertilizer, how much and where they are used, chemical composition, etc.
Date: December 1, 1994
Creator: Berry, J.T.
Partner: UNT Libraries Government Documents Department

Geochemistry of core samples of the Tiva Canyon Tuff from drill hole UE-25 NRG{number_sign}3, Yucca Mountain, Nevada

Description: The Tiva Canyon Tuff of Miocene age is composed of crystal-poor, high-silica rhyolite overlain by a crystal-rich zone that is gradational in composition from high-silica rhyolite to quartz latite. Each of these zones is divided into subzones that have distinctive physical, mineralogical, and geochemical features.Accurate identification of these subzones and their contacts is essential for detailed mapping and correlation both at the surface and in the subsurface in drill holes and in the exploratory studies facility (ESF). This report presents analyses of potassium (K), calcium (Ca), titanium (Ti), rubidium (Rb), strontium (Sr), yttrium (Y), zirconium (Zr), niobium (Nb), barium (Ba), lanthanum (La), and cerium (Ce) in core samples of the Tiva Canyon Tuff from drill hole UE-25 NRG {number_sign}3. The concentrations of most of these elements are remarkably constant throughout the high-silica rhyolite, but at its upper contact with the crystal-rich zone, Ti, Zr, Ba, Ca, Sr, La, Ce, and K begin to increase progressively through the crystal-rich zone. In contrast, Rb and Nb decrease, and Y remains essentially constant. Initial {sup 87}Sr/{sup 86}Sr ratios are relatively uniform in the high-silica rhyolite with a mean value of 0.7117, whereas initial {sup 87}Sr/{sup 86}Sr ratios decrease upward in the quartz latite to values as low as 0.7090.
Date: July 1, 1996
Creator: Peterman, Z.E. & Futa, K.
Partner: UNT Libraries Government Documents Department

BPO crude oil analysis data base user`s guide: Methods, publications, computer access correlations, uses, availability

Description: The Department of Energy (DOE) has one of the largest and most complete collections of information on crude oil composition that is available to the public. The computer program that manages this database of crude oil analyses has recently been rewritten to allow easier access to this information. This report describes how the new system can be accessed and how the information contained in the Crude Oil Analysis Data Bank can be obtained.
Date: March 1, 1996
Creator: Sellers, C.; Fox, B. & Paulz, J.
Partner: UNT Libraries Government Documents Department

Lunar prospector measurements of the distribution of incompatible elements gadolinium, samarium and thorium

Description: Lunar Prospector neutron spectrometer (NS) and gamma ray spectrometer (GRS) observations have been used to map out the distribution of incompatible elements on the lunar surface. Specifically, the GRS data provide maps of the distribution of thorium and potassium while the NS data provide information on the distribution of iron and titanium, and the rare earth elements gadolinium and samarium. Using results of analysis of Celementine spectral reflectance (CSR) data, the Fe- and Ti-contributions to the NS data can be removed, leaving primarily rare earth element contributions from Gd and Sm. The Th and K maps correlate with the inferred Gd and Sm maps (r {approximately} 0.93), but there are regions of significant disagreement. One of these is in the KREEP-rich circum-Imbrium ring. No clear explanation has emerged for this disagreement, though Th, K, Gd and Sm have differing degrees of incompatibility. These results clearly are important to discussions of the geochemistry of the Procellarum-Imbrium Th-rich Terrane and the South-Pole-Aitken Terrane.
Date: April 1, 1999
Creator: Elphic, R.C.; Lawrence, D.J.; Feldman, W.C.; Barraclough, B.L.; Maurice, S.; Binder, A.B. et al.
Partner: UNT Libraries Government Documents Department

Chiral separation of pharmaceutical compounds using electrochemically modulated liquid chromatography (EMLC)

Description: This research explores the application of a new technique, termed electrochemically modulated liquid chromatography (EMLC), to the chiral separations of pharmaceutical compounds. The introduction section provides a literature review of the technique and its applications, as well as brief overview of the research described in each of the next two chapters. Chapter 2 investigates the EMLC-based enantiomeric separation of a group of chiral benzodiazepines with {beta}-cyclodextrin as a chiral mobile phase additive. Chapter 3 demonstrates the effects of several experimental parameters on the separation efficiency of drug enantiomers. The author concludes with a general summary and possible directions for future studies. Chapters 2 and 3 are processed separately.
Date: February 12, 1999
Creator: Wang, S.
Partner: UNT Libraries Government Documents Department