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Sample records for as-doped buried amorphous

  1. Lithium implantation at low temperature in silicon for sharp buried amorphous layer formation and defect engineering

    SciTech Connect

    Oliviero, E.; David, M. L.; Beaufort, M. F.; Barbot, J. F.; Fichtner, P. F. P.

    2013-02-28

    The crystalline-to-amorphous transformation induced by lithium ion implantation at low temperature has been investigated. The resulting damage structure and its thermal evolution have been studied by a combination of Rutherford backscattering spectroscopy channelling (RBS/C) and cross sectional transmission electron microscopy (XTEM). Lithium low-fluence implantation at liquid nitrogen temperature is shown to produce a three layers structure: an amorphous layer surrounded by two highly damaged layers. A thermal treatment at 400 Degree-Sign C leads to the formation of a sharp amorphous/crystalline interfacial transition and defect annihilation of the front heavily damaged layer. After 600 Degree-Sign C annealing, complete recrystallization takes place and no extended defects are left. Anomalous recrystallization rate is observed with different motion velocities of the a/c interfaces and is ascribed to lithium acting as a surfactant. Moreover, the sharp buried amorphous layer is shown to be an efficient sink for interstitials impeding interstitial supersaturation and {l_brace}311{r_brace} defect formation in case of subsequent neon implantation. This study shows that lithium implantation at liquid nitrogen temperature can be suitable to form a sharp buried amorphous layer with a well-defined crystalline front layer, thus having potential applications for defects engineering in the improvement of post-implantation layers quality and for shallow junction formation.

  2. Reduction of channel resistance in amorphous oxide thin-film transistors with buried layer

    NASA Astrophysics Data System (ADS)

    Chong, Eugene; Kim, Bosul; Lee, Sang Yeol

    2012-04-01

    A silicon-indium-zinc-oxide (SIZO) thin film transistor (TFT) with low channel-resistance (RCH) indium-zinc-oxide (In2O3:ZnO = 9:1) buried layer annealed at low temperature of 200°C exhibited high field-effect mobility (μFE) over 55.8 cm2/V·s which is 5 times higher than that of the conventional TFTs due to small threshold voltage (Vth) change of 1.8 V under bias-temperature stress (BTS) condition for 420 minutes. The low-RCH buried-layer allows more strong current-path formed in channel layer well within relatively high-RCH channel-layer since it is less affected by the channel bulk and/or back interface trap with high carrier concentration.

  3. Impact of solid-phase crystallization of amorphous silicon on the chemical structure of the buried Si/ZnO thin film solar cell interface

    SciTech Connect

    Bar, M.; Wimmer, M.; Wilks, R. G.; Roczen, M.; Gerlach, D.; Ruske, F.; Lips, K.; Rech, B.; Weinhardt, L.; Blum, M.; Pookpanratana, S.; Krause, S.; Zhang, Y.; Heske, C.; Yang, W.; Denlinger, J. D.

    2010-04-30

    The chemical interface structure between phosphorus-doped hydrogenated amorphous silicon and aluminum-doped zinc oxide thin films is investigated with soft x-ray emission spectroscopy (XES) before and after solid-phase crystallization (SPC) at 600C. In addition to the expected SPC-induced phase transition from amorphous to polycrystalline silicon, our XES data indicates a pronounced chemical interaction at the buried Si/ZnO interface. In particular, we find an SPC-enhanced formation of Si-O bonds and the accumulation of Zn in close proximity to the interface. For an assumed closed and homogeneous SiO2 interlayer, an effective thickness of (5+2)nm after SPC could be estimated.

  4. Buried oxide layer in silicon

    DOEpatents

    Sadana, Devendra Kumar; Holland, Orin Wayne

    2001-01-01

    A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.

  5. Solubility products of amorphous ferric arsenate and crystalline scorodite (FeAsO 4 · 2H 2O) and their application to arsenic behavior in buried mine tailings

    NASA Astrophysics Data System (ADS)

    Langmuir, Donald; Mahoney, John; Rowson, John

    2006-06-01

    Published solubility data for amorphous ferric arsenate and scorodite have been reevaluated using the geochemical code PHREEQC with a modified thermodynamic database for the arsenic species. Solubility product calculations have emphasized measurements obtained under conditions of congruent dissolution of ferric arsenate (pH < 3), and have taken into account ion activity coefficients, and ferric hydroxide, ferric sulfate, and ferric arsenate complexes which have association constants of 10 4.04 (FeH 2AsO 42+), 10 9.86 (FeHAsO 4+), and 10 18.9 (FeAsO 4). Derived solubility products of amorphous ferric arsenate and crystalline scorodite (as log Ksp) are -23.0 ± 0.3 and -25.83 ± 0.07, respectively, at 25 °C and 1 bar pressure. In an application of the solubility results, acid raffinate solutions (molar Fe/As = 3.6) from the JEB uranium mill at McClean Lake in northern Saskatchewan were neutralized with lime to pH 2-8. Poorly crystalline scorodite precipitated below pH 3, removing perhaps 98% of the As(V) from solution, with ferric oxyhydroxide (FO) phases precipitated starting between pH 2 and 3. Between pH 2.18 and 7.37, the apparent log Ksp of ferric arsenate decreased from -22.80 to -24.67, while that of FO (as Fe(OH) 3) increased from -39.49 to -33.5. Adsorption of As(V) by FO can also explain the decrease in the small amounts of As(V)(aq) that remain in solution above pH 2-3. The same general As(V) behavior is observed in the pore waters of neutralized tailings buried for 5 yr at depths of up to 32 m in the JEB tailings management facility (TMF), where arsenic in the pore water decreases to 1-2 mg/L with increasing age and depth. In the TMF, average apparent log Ksp values for ferric arsenate and ferric hydroxide are -25.74 ± 0.88 and -37.03 ± 0.58, respectively. In the laboratory tests and in the TMF, the increasing crystallinity of scorodite and the amorphous character of the coexisting FO phase increases the stability field of scorodite relative to that of

  6. Buried Craters

    NASA Technical Reports Server (NTRS)

    2005-01-01

    26 December 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows two circular features on the plains of northern Utopia. A common sight on the martian northern plains, these rings indicate the locations of buried impact craters.

    Location near: 65.1oN, 261.2oW Image width: 2 km (1.2 mi) Illumination from: lower left Season: Northern Summer

  7. Buried Crater

    NASA Technical Reports Server (NTRS)

    2002-01-01

    [figure removed for brevity, see original site]

    With a location roughly equidistant between two of the largest volcanic constructs on the planet, the fate of the 50 km impact crater in this image was sealed. It has been buried to the rim by lava flows. The MOLA context image shows pronounced flow lobes surrounding the crater, a clear indication of the most recent episode of volcanism that could have contributed to its infilling. Breaches in the rim are clearly evident in the image and suggest locations through which lavas could have flowed. These openings appear to be limited to the west side of the crater. Other craters in the area are nearly obliterated by the voluminous lava flows, further demonstrating one of the means by which Mars renews its surface.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  8. Method of forming buried oxide layers in silicon

    DOEpatents

    Sadana, Devendra Kumar; Holland, Orin Wayne

    2000-01-01

    A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.

  9. Buried Craters of Utopia

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-365, 19 May 2003

    Beneath the northern plains of Mars are numerous buried meteor impact craters. One of the most heavily-cratered areas, although buried, occurs in Utopia Planitia, as shown in this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image. The history of Mars is complex; impact craters provide a tool by which to understand some of that history. In this case, a very ancient, cratered surface was thinly-buried by younger material that is not cratered at all. This area is near 48.1oN, 228.2oW; less than 180 km (112 mi) west of the Viking 2 lander site. Sunlight illuminates the scene from the lower left.

  10. Plasmonics in buried structures.

    PubMed

    Romero, I; García de Abajo, F J

    2009-10-12

    We describe plasmon propagation in silica-filled coupled nanovoids fully buried in gold. Propagation bands and band gaps are shown to be tunable through the degree of overlap and plasmon hybridization between contiguous voids. The effect of disorder and fabrication imperfections is thoroughly investigated. Our work explores a novel paradigm for plasmon photonics relying on plasmon modes in metal-buried structures, which can benefit from long propagation distances, cancelation of radiative losses, minimum crosstalk between neighboring waveguides, and maximum optical integration in three-dimensional arrangements.

  11. Cracked Plain, Buried Craters

    NASA Technical Reports Server (NTRS)

    2004-01-01

    4 September 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a cracked plain in western Utopia Planitia. The three circular crack patterns indicate the location of three buried meteor impact craters. These landforms are located near 41.9oN, 275.9oW. The image covers an area approximately 3 km (1.9 mi) across. Sunlight illuminates this scene from the lower left.

  12. Amorphic complexity

    NASA Astrophysics Data System (ADS)

    Fuhrmann, G.; Gröger, M.; Jäger, T.

    2016-02-01

    We introduce amorphic complexity as a new topological invariant that measures the complexity of dynamical systems in the regime of zero entropy. Its main purpose is to detect the very onset of disorder in the asymptotic behaviour. For instance, it gives positive value to Denjoy examples on the circle and Sturmian subshifts, while being zero for all isometries and Morse-Smale systems. After discussing basic properties and examples, we show that amorphic complexity and the underlying asymptotic separation numbers can be used to distinguish almost automorphic minimal systems from equicontinuous ones. For symbolic systems, amorphic complexity equals the box dimension of the associated Besicovitch space. In this context, we concentrate on regular Toeplitz flows and give a detailed description of the relation to the scaling behaviour of the densities of the p-skeletons. Finally, we take a look at strange non-chaotic attractors appearing in so-called pinched skew product systems. Continuous-time systems, more general group actions and the application to cut and project quasicrystals will be treated in subsequent work.

  13. Thin film buried anode battery

    DOEpatents

    Lee, Se-Hee; Tracy, C. Edwin; Liu, Ping

    2009-12-15

    A reverse configuration, lithium thin film battery (300) having a buried lithium anode layer (305) and process for making the same. The present invention is formed from a precursor composite structure (200) made by depositing electrolyte layer (204) onto substrate (201), followed by sequential depositions of cathode layer (203) and current collector (202) on the electrolyte layer. The precursor is subjected to an activation step, wherein a buried lithium anode layer (305) is formed via electroplating a lithium anode layer at the interface of substrate (201) and electrolyte film (204). The electroplating is accomplished by applying a current between anode current collector (201) and cathode current collector (202).

  14. Ultrasonic isolation of buried pipes

    NASA Astrophysics Data System (ADS)

    Leinov, Eli; Lowe, Michael J. S.; Cawley, Peter

    2016-02-01

    Long-range guided wave testing (GWT) is used routinely for the monitoring and detection of corrosion defects in above ground pipelines. The GWT test range in buried, coated pipelines is greatly reduced compared to above ground configurations due to energy leakage into the embedding soil. In this paper, the effect of pipe coatings on the guided wave attenuation is investigated with the aim of increasing test ranges for buried pipelines. The attenuation of the T(0,1) and L(0,2) guided wave modes is measured using a full-scale experimental apparatus in a fusion-bonded epoxy (FBE)-coated 8 in. pipe, buried in loose and compacted sand. Tests are performed over a frequency range typically used in GWT of 10-35 kHz and compared with model predictions. It is shown that the application of a low impedance coating between the FBE layer and the sand effectively decouples the influence of the sand on the ultrasound leakage from the buried pipe. Ultrasonic isolation of a buried pipe is demonstrated by coating the pipe with a Polyethylene (PE)-foam layer that has a smaller impedance than both the pipe and sand, and has the ability to withstand the overburden load from the sand. The measured attenuation in the buried PE-foam-FBE-coated pipe is found to be substantially reduced, in the range of 0.3-1.2 dB m-1 for loose and compacted sand conditions, compared to measured attenuation of 1.7-4.7 dB m-1 in the buried FBE-coated pipe without the PE-foam. The acoustic properties of the PE-foam are measured independently using ultrasonic interferometry and incorporated into model predictions of guided wave propagation in buried coated pipe. Good agreement is found between the experimental measurements and model predictions. The attenuation exhibits periodic peaks in the frequency domain corresponding to the through-thickness resonance frequencies of the coating layer. The large reduction in guided wave attenuation for PE-coated pipes would lead to greatly increased GWT test ranges; such

  15. The Buried Town of Beaver.

    ERIC Educational Resources Information Center

    Jostad, Karen

    Local history as source material for environmental education is uniquely portrayed in this resource kit. Utilizing a Winona County Historical Society publication, "The Beaver Story" and accompanied by a teacher's guide, "The Buried Town of Beaver," and other teaching aids, a case study of the area can be developed. Based on the reminiscences of…

  16. Amorphous metal composites

    DOEpatents

    Byrne, Martin A.; Lupinski, John H.

    1984-01-01

    An improved amorphous metal composite and process of making the composite. The amorphous metal composite comprises amorphous metal (e.g. iron) and a low molecular weight thermosetting polymer binder. The process comprises placing an amorphous metal in particulate form and a thermosetting polymer binder powder into a container, mixing these materials, and applying heat and pressure to convert the mixture into an amorphous metal composite.

  17. Buried metalic object identification by EMI sensor

    NASA Astrophysics Data System (ADS)

    Sezgin, Mehmet; Kaplan, Gülay; Birim, Melih; Bahadırlar, Yıldırım

    2007-04-01

    Electromagnetic Induction sensor (Metal Detector) has wide application areas for buried metallic object searching, such as detection of buried pipes, mine and mine like-targets, etc. In this paper, identification of buried metallic objects was studied. The distinctive features of the signal were obtained, than classification process was performed. Identification process was realized by utilizing k-Nearest neighbor and Neural Network Classifiers.

  18. Electromagnetic scattering from buried objects

    SciTech Connect

    Brock, B.C.; Sorensen, K.W.

    1994-10-01

    Radar imaging and detection of objects buried in soil has potentially important applications in the areas of nonproliferation of weapons, environmental monitoring, hazardous-waste site location and assessment, and even archeology. In order to understand and exploit this potential, it is first necessary to understand how the soil responds to an electromagnetic wave, and how targets buried within the soil scatter the electromagnetic wave. We examine the response of the soil to a short pulse, and illustrate the roll of the complex dielectric permittivity of the soil in determining radar range resolution. This leads to a concept of an optimum frequency and bandwidth for imaging in a particular soil. We then propose a new definition for radar cross section which is consistent with the modified radar equation for use with buried targets. This radar cross section plays the same roll in the modified radar equation as the traditional radar cross section does in the free-space radar equation, and is directly comparable to it. The radar cross section of several canonical objects in lossy media is derived, and examples are given for several object/soil combinations.

  19. BATATA: a buried muon hodoscope

    NASA Astrophysics Data System (ADS)

    Sánchez, F.; Supanitsky, A. D.; Medina-Tanco, G.; Paic, G.; Salazar, M. E. Patiño; D'Olivo, J. C.; Molina, R. Alfaro

    2009-04-01

    Muon hodoscopes have several applications, ranging from astrophysics to fundamental particle physics. In this work, we present a detector dedicated to the study, at ground level, of the main signals of cosmic-ray induced showers above 6 PeV. The whole detector is composed by a set of three parallel dual-layer scintillator planes buried at fix depths ranging from 120 g/cm2 to 600 g/cm2 and by a triangular array of water cerenkov detectors located nearby on ground.

  20. Blast wave from buried charges

    SciTech Connect

    Reichenbach, H.; Behrens, K.; Kuhl, A.L.

    1993-08-01

    While much airblast data are available for height-of-burst (HOB) effects, systematic airblast data for depth-of-burst (DOB) effects are more limited. It is logical to ask whether the spherical 0.5-g Nitropenta charges that, proved to be successful for HOB tests at EMI are also suitable for experiments with buried charges in the laboratory scale; preliminary studies indicated in the alternative. Of special interest is the airblast environment generated by detonations just above or below the around surface. This paper presents a brief summary of the test results.

  1. Theory of amorphous ices

    PubMed Central

    Limmer, David T.; Chandler, David

    2014-01-01

    We derive a phase diagram for amorphous solids and liquid supercooled water and explain why the amorphous solids of water exist in several different forms. Application of large-deviation theory allows us to prepare such phases in computer simulations. Along with nonequilibrium transitions between the ergodic liquid and two distinct amorphous solids, we establish coexistence between these two amorphous solids. The phase diagram we predict includes a nonequilibrium triple point where two amorphous phases and the liquid coexist. Whereas the amorphous solids are long-lived and slowly aging glasses, their melting can lead quickly to the formation of crystalline ice. Further, melting of the higher density amorphous solid at low pressures takes place in steps, transitioning to the lower-density glass before accessing a nonequilibrium liquid from which ice coarsens. PMID:24858957

  2. Seismic assessment of buried pipelines

    SciTech Connect

    Al-Chaar, G.; Brady, P.; Fernandez, G.

    1995-12-31

    A structure and its lifelines are closely linked because the disruption of lifeline systems will obstruct emergency service functions that are vitally needed after an earthquake. As an example of the criticality of these systems, the Association of Bay Area Government (ABAG) recorded thousands of leaks in pipelines that resulted in more than twenty million gallons of hazardous materials being released in several recorded earthquakes. The cost of cleaning the spills from these materials was very high. This information supports the development of seismic protection of lifeline systems. The US Army Corps of Engineers Construction Engineering Research Laboratories (USACERL) has, among its missions, the responsibility to develop seismic vulnerability assessment procedures for military installations. Within this mission, a preliminary research program to assess the seismic vulnerability of buried pipeline systems on military installations was initiated. Phase 1 of this research project resulted in two major studies. In the first, evaluating current procedures to seismically design or evaluate existing lifeline systems, the authors found several significant aspects that deserve special consideration and need to be addressed in future research. The second was focused on identifying parameters related to buried pipeline system vulnerability and developing a generalized analytical method to relate these parameters to the seismic vulnerability assessment of existing pipeline systems.

  3. Nanocrystal dispersed amorphous alloys

    NASA Technical Reports Server (NTRS)

    Perepezko, John H. (Inventor); Allen, Donald R. (Inventor); Foley, James C. (Inventor)

    2001-01-01

    Compositions and methods for obtaining nanocrystal dispersed amorphous alloys are described. A composition includes an amorphous matrix forming element (e.g., Al or Fe); at least one transition metal element; and at least one crystallizing agent that is insoluble in the resulting amorphous matrix. During devitrification, the crystallizing agent causes the formation of a high density nanocrystal dispersion. The compositions and methods provide advantages in that materials with superior properties are provided.

  4. A Buried Precambrian Impact Crater in Scotland

    NASA Astrophysics Data System (ADS)

    Simms, M. J.

    2016-08-01

    Field evidence indicates that the source of the Stac Fada impact deposit (Mesoproterozoic) in NW Scotland was to the east, and that the now buried crater is represented by the 40+ km diameter Lairg Gravity Low.

  5. Trehalose amorphization and recrystallization.

    PubMed

    Sussich, Fabiana; Cesàro, Attilio

    2008-10-13

    The stability of the amorphous trehalose prepared by using several procedures is presented and discussed. Amorphization is shown to occur by melting (T(m)=215 degrees C) or milling (room temperature) the crystalline anhydrous form TRE-beta. Fast dehydration of the di-hydrate crystalline polymorph, TRE-h, also produces an amorphous phase. Other dehydration procedures of TRE-h, such as microwave treatment, supercritical extraction or gentle heating at low scan rates, give variable fractions of the polymorph TRE-alpha, that undergo amorphization upon melting (at lower temperature, T(m)=130 degrees C). Additional procedures for amorphization, such as freeze-drying, spray-drying or evaporation of trehalose solutions, are discussed. All these procedures are classified depending on the capability of the undercooled liquid phase to undergo cold crystallization upon heating the glassy state at temperatures above the glass transition temperature (T(g)=120 degrees C). The recrystallizable amorphous phase is invariably obtained by the melt of the polymorph TRE-alpha, while other procedures always give an amorphous phase that is unable to crystallize above T(g). The existence of two different categories is analyzed in terms of the transformation paths and the hypothesis that the systems may exhibit different molecular mobilities.

  6. Hydrogen in amorphous silicon

    SciTech Connect

    Peercy, P. S.

    1980-01-01

    The structural aspects of amorphous silicon and the role of hydrogen in this structure are reviewed with emphasis on ion implantation studies. In amorphous silicon produced by Si ion implantation of crystalline silicon, the material reconstructs into a metastable amorphous structure which has optical and electrical properties qualitatively similar to the corresponding properties in high-purity evaporated amorphous silicon. Hydrogen studies further indicate that these structures will accomodate less than or equal to 5 at.% hydrogen and this hydrogen is bonded predominantly in a monohydride (SiH/sub 1/) site. Larger hydrogen concentrations than this can be achieved under certain conditions, but the excess hydrogen may be attributed to defects and voids in the material. Similarly, glow discharge or sputter deposited amorphous silicon has more desirable electrical and optical properties when the material is prepared with low hydrogen concentration and monohydride bonding. Results of structural studies and hydrogen incorporation in amorphous silicon were discussed relative to the different models proposed for amorphous silicon.

  7. Buried Waste Integrated Demonstration. Technology summary

    SciTech Connect

    Not Available

    1994-03-01

    The Buried Waste Integrated Demonstration (BWID) supports the applied research, development, demonstration, and evaluation of a suite of advanced technologies that offer promising solutions to the problems associated with the remediation of buried waste. BWID addresses the difficult remediation problems associated with DOE complex-wide buried waste, particularly transuranic (TRU) contaminated buried waste. BWID has implemented a systems approach to the development and demonstration of technologies that will characterize, retrieve, treat, and dispose of DOE buried wastes. This approach encompasses the entire remediation process from characterization to post-monitoring. The development and demonstration of the technology is predicated on how a technology fits into the total remediation process. To address all of these technological issues, BWID has enlisted scientific expertise of individuals and groups from within the DOE Complex, as well as experts from universities and private industry. The BWID mission is to support development and demonstration of a suite of technologies that, when integrated with commercially-available technologies, forms a comprehensive, remediation system for the effective and efficient remediation of buried waste throughout the DOE Complex. BWID will evaluate and validate demonstrated technologies and transfer this information and equipment to private industry to support the Office of Environmental Restoration (ER), Office of Waste Management (WM), and Office of Facility Transition (FT) remediation planning and implementation activities.

  8. Amorphous diamond films

    DOEpatents

    Falabella, S.

    1998-06-09

    Amorphous diamond films having a significant reduction in intrinsic stress are prepared by biasing a substrate to be coated and depositing carbon ions thereon under controlled temperature conditions. 1 fig.

  9. Amorphous pharmaceutical solids.

    PubMed

    Vranić, Edina

    2004-07-01

    Amorphous forms are, by definition, non-crystalline materials which possess no long-range order. Their structure can be thought of as being similar to that of a frozen liquid with the thermal fluctuations present in a liquid frozen out, leaving only "static" structural disorder. The amorphous solids have always been an essential part of pharmaceutical research, but the current interest has been raised by two developments: a growing attention to pharmaceutical solids in general, especially polymorphs and solvates and a revived interest in the science of glasses and the glass transition. Amorphous substances may be formed both intentionally and unintentionally during normal pharmaceutical manufacturing operations. The properties of amorphous materials can be exploited to improve the performance of pharmaceutical dosage forms, but these properties can also give rise to unwanted effects that need to be understood and managed in order for the systems to perform as required.

  10. Arsenic complexes optical signatures in As-doped HgCdTe

    SciTech Connect

    Gemain, F.; Robin, I. C.; Brochen, S.; Ballet, P.; Gravrand, O.; Feuillet, G.

    2013-04-08

    In this paper, the optical signatures of arsenic complexes in As-doped HgCdTe samples grown by molecular beam epitaxy are clearly identified using comparison between photoluminescence spectra, Extended X-Ray Absorption Fine Structure, and Hall measurements. The ionization energies of the different complexes are measured both by photoluminescence and Hall measurements.

  11. Amorphous metal alloy

    DOEpatents

    Wang, R.; Merz, M.D.

    1980-04-09

    Amorphous metal alloys of the iron-chromium and nickel-chromium type have excellent corrosion resistance and high temperature stability and are suitable for use as a protective coating on less corrosion resistant substrates. The alloys are stabilized in the amorphous state by one or more elements of titanium, zirconium, hafnium, niobium, tantalum, molybdenum, and tungsten. The alloy is preferably prepared by sputter deposition.

  12. Remote technologies for buried waste retrieval

    SciTech Connect

    Smith, A.M.; Rice, P.

    1995-10-01

    The DOE is evaluating what should be done with this buried waste. Although the radioactive waste is not particularly mobile unless airborne, some of it was buried with volatile organics and/or other substances that tend to spread easily to surrounding soil or water tables. Volatile organics are hazardous materials (such as trichloroethylene) and require clean-up at certain levels in drinking water. There is concern that the buried volatile organics will spread into the water table and contaminate drinking water. Because of this, the DOE is considering options for handling this buried waste and reducing the risks of spreading or exposure. There are two primary options: containment and stabilization, or retrieval. Containment and stabilization systems would include systems that would leave the waste where it is, but contain and stabilize it so that the radioactive and hazardous materials would not spread to the surrounding soil, water, or air. For example, an in situ vitrification system could be used to melt the waste into a composite glass-like material that would not leach into the surrounding soil, water, or air. Retrieval systems are those that would remove the waste from its burial location for treatment and/or repackaging for long term storage. The objective of this project was to develop and demonstrate remote technologies that would minimize dust generation and the spread of airborne contaminants during buried waste retrieval. Remote technologies are essential for the retrieval of buried waste because they remove workers from the hazardous environment and provide greater automation, reducing the chances of human error. Minimizing dust generation is also essential to increased safety for the workers and the environment during buried waste retrieval. The main contaminants within the waste are micron-sized particles of plutonium and americium oxides, chlorides, and hydroxides, which are easily suspended in air and spread if disturbed.

  13. Ballistic electron spectroscopy of individual buried molecules

    NASA Astrophysics Data System (ADS)

    Kirczenow, George

    2007-01-01

    A theoretical study is presented of the ballistic electron emission spectra (BEES) of individual insulating and conducting organic molecules chemisorbed on a silicon substrate and buried under a thin gold film. It is predicted that ballistic electrons injected into the gold film from a scanning tunneling microscope tip should be transmitted so weakly to the silicon substrate by alkane molecules of moderate length (decane, hexane) and their thiolates that individual buried molecules of this type will be difficult to detect in BEES experiments. However, resonant transmission by molecules containing unsaturated C-C bonds or aromatic rings is predicted to be strong enough for BEES spectra of individual buried molecules of these types to be measured. Calculated BEES spectra of molecules of both types are presented and the effects of some simple interstitial and substitutional gold defects that may occur in molecular films are also briefly discussed.

  14. Formation of amorphous materials

    DOEpatents

    Johnson, William L.; Schwarz, Ricardo B.

    1986-01-01

    Metastable amorphous or fine crystalline materials are formed by solid state reactions by diffusion of a metallic component into a solid compound or by diffusion of a gas into an intermetallic compound. The invention can be practiced on layers of metals deposited on an amorphous substrate or by intermixing powders with nucleating seed granules. All that is required is that the diffusion of the first component into the second component be much faster than the self-diffusion of the first component. The method is practiced at a temperature below the temperature at which the amorphous phase transforms into one or more crystalline phases and near or below the temperature at which the ratio of the rate of diffusion of the first component to the rate of self-diffusion is at least 10.sup.4. This anomalous diffusion criteria is found in many binary, tertiary and higher ordered systems of alloys and appears to be found in all alloy systems that form amorphous materials by rapid quenching. The method of the invention can totally convert much larger dimensional materials to amorphous materials in practical periods of several hours or less.

  15. Seismic damage estimation for buried pipeline systems

    SciTech Connect

    Heubach, W.F.

    1995-12-31

    A methodology for estimating seismic damage rates for buried pipeline systems is presented. The methodology is intended for damage estimation of buried pipeline systems in areas where use of more rigorous structural analysis techniques is not practical. Damage is estimated for areas subjected to ground shaking and permanent ground deformation. Although the methodology employs previously developed ground shaking damage algorithms, new damage algorithms are developed for permanent ground deformation. These new algorithms reflect the high levels of damage observed in areas of soil liquefaction.

  16. Prioritization for rehabilitation of buried lifelines

    SciTech Connect

    Wang, L.R.L.; Ishibashi, I.; Li, H.

    1995-12-31

    Seismic rehabilitation or retrofit is a cost-effective way to prevent pipeline damage caused by future earthquakes. In general, it is very difficult, if not impossible, to rehabilitate all buried pipelines at the same time because of limited funds and time available. The purpose of this study is to establish a priority strategy for rehabilitation of buried pipelines considering several important factors such as pipeline damage probability, rehabilitation cost, rehabilitation rate (e.g. km/day), pipeline importance and total funds available.

  17. Buried Waste Integrated Demonstration stakeholder involvement model

    SciTech Connect

    Kaupanger, R.M.; Kostelnik, K.M.; Milam, L.M.

    1994-04-01

    The Buried Waste Integrated Demonstration (BWID) is a program funded by the US Department of Energy (DOE) Office of Technology Development. BWID supports the applied research, development, demonstration, and evaluation of a suite of advanced technologies that together form a comprehensive remediation system for the effective and efficient remediation of buried waste. Stakeholder participation in the DOE Environmental Management decision-making process is critical to remediation efforts. Appropriate mechanisms for communication with the public, private sector, regulators, elected officials, and others are being aggressively pursued by BWID to permit informed participation. This document summarizes public outreach efforts during FY-93 and presents a strategy for expanded stakeholder involvement during FY-94.

  18. Silicon on insulator with active buried regions

    DOEpatents

    McCarthy, Anthony M.

    1996-01-01

    A method for forming patterned buried components, such as collectors, sources and drains, in silicon-on-insulator (SOI) devices. The method is carried out by epitaxially growing a suitable sequence of single or multiple etch stop layers ending with a thin silicon layer on a silicon substrate, masking the silicon such that the desired pattern is exposed, introducing dopant and activating in the thin silicon layer to form doped regions. Then, bonding the silicon layer to an insulator substrate, and removing the silicon substrate. The method additionally involves forming electrical contact regions in the thin silicon layer for the buried collectors.

  19. Silicon on insulator with active buried regions

    DOEpatents

    McCarthy, A.M.

    1998-06-02

    A method is disclosed for forming patterned buried components, such as collectors, sources and drains, in silicon-on-insulator (SOI) devices. The method is carried out by epitaxially growing a suitable sequence of single or multiple etch stop layers ending with a thin silicon layer on a silicon substrate, masking the silicon such that the desired pattern is exposed, introducing dopant and activating in the thin silicon layer to form doped regions. Then, bonding the silicon layer to an insulator substrate, and removing the silicon substrate. The method additionally involves forming electrical contact regions in the thin silicon layer for the buried collectors. 10 figs.

  20. Silicon on insulator with active buried regions

    DOEpatents

    McCarthy, A.M.

    1996-01-30

    A method is disclosed for forming patterned buried components, such as collectors, sources and drains, in silicon-on-insulator (SOI) devices. The method is carried out by epitaxially growing a suitable sequence of single or multiple etch stop layers ending with a thin silicon layer on a silicon substrate, masking the silicon such that the desired pattern is exposed, introducing dopant and activating in the thin silicon layer to form doped regions. Then, bonding the silicon layer to an insulator substrate, and removing the silicon substrate. The method additionally involves forming electrical contact regions in the thin silicon layer for the buried collectors. 10 figs.

  1. Silicon on insulator with active buried regions

    DOEpatents

    McCarthy, Anthony M.

    1998-06-02

    A method for forming patterned buried components, such as collectors, sources and drains, in silicon-on-insulator (SOI) devices. The method is carried out by epitaxially growing a suitable sequence of single or multiple etch stop layers ending with a thin silicon layer on a silicon substrate, masking the silicon such that the desired pattern is exposed, introducing dopant and activating in the thin silicon layer to form doped regions. Then, bonding the silicon layer to an insulator substrate, and removing the silicon substrate. The method additionally involves forming electrical contact regions in the thin silicon layer for the buried collectors.

  2. Limited Panniculectomy for Adult Buried Penis Repair.

    PubMed

    Figler, Bradley D; Chery, Lisly; Friedrich, Jeffrey B; Wessells, Hunter; Voelzke, Bryan B

    2015-11-01

    Patients with buried or hidden penis may be unable to carry out normal hygiene, void with a directable urine stream, or be sexually active as a result of the condition. Although these patients are nearly always obese, weight loss often does not reverse the problem, as the mons pannus may remain after weight loss. Furthermore, associated penile skin changes such as lichen sclerosus or stenosis of the penile shaft skin are often irreversible. Treatment includes removal of the diseased shaft skin surrounding the penis, in combination with a limited panniculectomy. The authors present their technique for this procedure in a typical patient with buried penis that prevented him from voiding effectively.

  3. Structural Amorphous Steels

    NASA Astrophysics Data System (ADS)

    Lu, Z. P.; Liu, C. T.; Thompson, J. R.; Porter, W. D.

    2004-06-01

    Recent advancement in bulk metallic glasses, whose properties are usually superior to their crystalline counterparts, has stimulated great interest in fabricating bulk amorphous steels. While a great deal of effort has been devoted to this field, the fabrication of structural amorphous steels with large cross sections has remained an alchemist’s dream because of the limited glass-forming ability (GFA) of these materials. Here we report the discovery of structural amorphous steels that can be cast into glasses with large cross-section sizes using conventional drop-casting methods. These new steels showed interesting physical, magnetic, and mechanical properties, along with high thermal stability. The underlying mechanisms for the superior GFA of these materials are discussed.

  4. Preputial flaps to correct buried penis.

    PubMed

    Chu, Chih-Chun; Chen, Yi-Hsin; Diau, Guan-Yeu; Loh, Ih-Wei; Chen, Ke-Chi

    2007-11-01

    The authors developed a preputial skin flap technique to correct the buried penis which was simple and practical. This simple procedure can be applied to most boys with buried penis. In the last 3 years, we have seen 12 boys with buried penis and have been treated by using preputial flaps. The mean age is about 5.1 (from 3 to 12). By making a longitudinal incision on the ventral side of penis, the tightness of the foreskin is released and leave a diamond-shaped skin defect. It allows the penile shaft to extend out. A circumferential incision is made about 5 mm proximal to the coronal sulcus. Pedicled preputial flaps are obtained leaving optimal penile skin on the dorsal side. The preputial skin flaps are rotated onto the ventral side and tailored to cover the defect. All patients are followed for at least 3 months. Edema and swelling on the flaps are common, but improves with time. None of our patients need a second operation. The preputial flaps technique is a simple technique which allows surgeons to deal with most cases of buried penis by tailoring the flaps providing good cosmetic and functional results.

  5. Prestressing buried pipelines by heating with air

    SciTech Connect

    King, G. )

    1993-11-01

    Buried pipelines operating at elevated temperatures experience high longitudinal compressive stresses because the surrounding soil prevents thermal expansion. At high operating temperatures, buried pipelines can push through the soil at bends and buckle catastrophically. In soft soils they can lose lateral stability, and they can develop plastic failures. Thermally induced problems can be prevented with varying degrees of success by using thicker wall pipe, higher strength prevented with varying degrees of success by using thicker wall pipe, higher strength steel, longer radius bends, deeper burial, better backfill compaction, and/or prestressing during construction. Prestressing is most appropriate for pipelines operating at temperatures more than 80 C above ambient. One technique for prestressing a buried pipeline, that has been found to be both easy and economical for a liquid sulfur pipeline in Alberta, is to heat it with hot air and bury it while it is still hot. Pipe diameter and prestressing temperature both have a significant impact on the kind of heating equipment that is required.

  6. Amorphous silicon photovoltaic devices

    DOEpatents

    Carlson, David E.; Lin, Guang H.; Ganguly, Gautam

    2004-08-31

    This invention is a photovoltaic device comprising an intrinsic or i-layer of amorphous silicon and where the photovoltaic device is more efficient at converting light energy to electric energy at high operating temperatures than at low operating temperatures. The photovoltaic devices of this invention are suitable for use in high temperature operating environments.

  7. Sensor feature fusion for detecting buried objects

    SciTech Connect

    Clark, G.A.; Sengupta, S.K.; Sherwood, R.J.; Hernandez, J.E.; Buhl, M.R.; Schaich, P.C.; Kane, R.J.; Barth, M.J.; DelGrande, N.K.

    1993-04-01

    Given multiple registered images of the earth`s surface from dual-band sensors, our system fuses information from the sensors to reduce the effects of clutter and improve the ability to detect buried or surface target sites. The sensor suite currently includes two sensors (5 micron and 10 micron wavelengths) and one ground penetrating radar (GPR) of the wide-band pulsed synthetic aperture type. We use a supervised teaming pattern recognition approach to detect metal and plastic land mines buried in soil. The overall process consists of four main parts: Preprocessing, feature extraction, feature selection, and classification. These parts are used in a two step process to classify a subimage. Thee first step, referred to as feature selection, determines the features of sub-images which result in the greatest separability among the classes. The second step, image labeling, uses the selected features and the decisions from a pattern classifier to label the regions in the image which are likely to correspond to buried mines. We extract features from the images, and use feature selection algorithms to select only the most important features according to their contribution to correct detections. This allows us to save computational complexity and determine which of the sensors add value to the detection system. The most important features from the various sensors are fused using supervised teaming pattern classifiers (including neural networks). We present results of experiments to detect buried land mines from real data, and evaluate the usefulness of fusing feature information from multiple sensor types, including dual-band infrared and ground penetrating radar. The novelty of the work lies mostly in the combination of the algorithms and their application to the very important and currently unsolved operational problem of detecting buried land mines from an airborne standoff platform.

  8. Regrowth-related defect formation and evolution in 1 MeV amorphized (001) Ge

    SciTech Connect

    Hickey, D. P.; Bryan, Z. L.; Jones, K. S.; Elliman, R. G.; Haller, E. E.

    2007-03-26

    Ge implanted with 1 MeV Si{sup +} at a dose of 1x10{sup 15} cm{sup -2} creates a buried amorphous layer that, upon regrowth, exhibits several forms of defects-end-of-range (EOR), regrowth-related, and clamshell defects. Unlike Si, no planar (311) defects are observed. The minimal EOR defects are small dotlike defects and are very unstable, dissolving between 450 and 550 deg. C. This is in contrast to Si, where the EOR defects are very stable. The amorphous layer results in both regrowth-related defects and clamshell defects, which were more stable than the EOR damage.

  9. [Growth hormone and IGF-1 as doping agents in competitive sport].

    PubMed

    Jóźków, Paweł; Medraś, Marek

    2009-01-01

    Growth hormone (GH) and insulin-like growth factor 1 (IGF-1) are often used by athletes as doping agents. It is estimated that up to 25% of sportsmen using anabolic-androgenic steroids also take GH. Available data do not confirm the influence of GH or IGF-1 preparations on physical performance improvement. However, there is some evidences for many adverse effects in athletes using this form of doping. Blood tests to detect growth hormone abuse are available since several years. Surprisingly, no one has been proven to use illegal doping agents influencing GH/IGF-1 axis.

  10. Amorphous silicon radiation detectors

    DOEpatents

    Street, Robert A.; Perez-Mendez, Victor; Kaplan, Selig N.

    1992-01-01

    Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification.

  11. Amorphous silicon radiation detectors

    DOEpatents

    Street, R.A.; Perez-Mendez, V.; Kaplan, S.N.

    1992-11-17

    Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification. 13 figs.

  12. Amorphous metallic foam

    NASA Astrophysics Data System (ADS)

    Schroers, Jan; Veazey, Chris; Johnson, William L.

    2003-01-01

    The bulk glass forming alloy Pd43Ni10Cu27P20 is processed into a low-density amorphous metallic foam. Pd43Ni10Cu27P20 is mixed with hydrated B2O3, which releases gas at elevated temperature and/or low pressure. Very homogeneous foams are achieved due to the high viscosity of the alloy even at its liquidus temperature. By processing at the liquidus temperature and decreasing the pressure to 10-2 mbar, well-distributed bubbles expand to foam the material. Foam densities as low as 1.4×103 kg/m3 were obtained, corresponding to a bubble volume fraction of 84%. The bubble diameter ranges between 2×10-4 and 1×10-3 m. Thermal analysis by differential scanning calorimetry confirms the amorphous nature of the foam. Furthermore, it reveals that the foam's thermal stability is comparable to the bulk material.

  13. Buried pipelines in large fault movements

    SciTech Connect

    Wang, L.J.; Wang, L.R.L.

    1995-12-31

    Responses of buried pipelines in large fault movements are examined based upon a non-linear cantilever beam analogy. This analogy assumes that the pipeline in a large deflection zone behaves like a cantilever beam under a transverse-concentrated shear at the inflection point with a uniformly distributed soil pressure along the entire span. The tangent modulus approach is adopted to analyze the coupled axial force-bending moment interaction on pipeline deformations in the inelastic range. The buckling load of compressive pipeline is computed by the modified Newmark`s numerical integration scheme. Parametric studies of both tensile and compressive pipeline responses to various fault movements, pipeline/fault crossing angles, soil/pipe friction angles, buried depths, pipe diameters and thickness are investigated. It is shown by the comparisons that previous findings were unconservative.

  14. Shell model response analysis of buried pipelines

    SciTech Connect

    Takada, Shiro; Katagiri, Shin; Shinmi, Tatsuhiko

    1995-12-31

    A shell model analysis can calculate the cross-sectional deformation and hoop stress of buried pipelines. This paper proposes an analytical method to calculate the response of buried straight and bent pipelines modeled as cylindrical shell structures. A modified transfer matrix method is employed instead of a stiffness matrix method to avoid the problem of computational memory caused by huge matrixes. Results calculated by the developed program are compared with experimental ones obtained by a pipe bending test of straight and bent pipe segments. In addition, several differences of the pipe response between the beam model and the shell model are examined through response simulations of straight and bent pipelines subjected to ground subsidence.

  15. Buried Waste Integrated Demonstration Strategy Plan

    SciTech Connect

    Kostelnik, K.M.

    1993-02-01

    The Buried Waste Integrated Demonstration (BWID) supports the applied research, development, demonstration, and evaluation of a suite of advanced technologies that form a comprehensive remediation system for the effective and efficient remediation of buried waste. These efforts are identified and coordinated in support of the US Department of Energy (DOE), Environmental Restoration and Waste Management (ERWM) needs and objectives. The present focus of BWID is to support retrieval and ex situ treatment configuration options. Future activities will explore and support containment and stabilization efforts in addition to the retrieval/ex situ treatment options. Long and short term strategies of the BWID are provided. Processes for identifying technological needs, screening candidate technologies for BWID applicability, researching technical issues, field demonstrating technologies, evaluating demonstration results to determine each technology`s threshold of capability, and commercializing successfully demonstrated technologies for implementation for environmental restoration also are presented in this report.

  16. Buried Waste Integrated Demonstration Strategy Plan

    SciTech Connect

    Kostelnik, K.M.

    1993-02-01

    The Buried Waste Integrated Demonstration (BWID) supports the applied research, development, demonstration, and evaluation of a suite of advanced technologies that form a comprehensive remediation system for the effective and efficient remediation of buried waste. These efforts are identified and coordinated in support of the US Department of Energy (DOE), Environmental Restoration and Waste Management (ERWM) needs and objectives. The present focus of BWID is to support retrieval and ex situ treatment configuration options. Future activities will explore and support containment and stabilization efforts in addition to the retrieval/ex situ treatment options. Long and short term strategies of the BWID are provided. Processes for identifying technological needs, screening candidate technologies for BWID applicability, researching technical issues, field demonstrating technologies, evaluating demonstration results to determine each technology's threshold of capability, and commercializing successfully demonstrated technologies for implementation for environmental restoration also are presented in this report.

  17. Defects in Amorphous Metals.

    DTIC Science & Technology

    1982-07-01

    this map with a similar plot of the experimental data. An experimental deformation data map for Pd-based amorphous al- loys is shown in fig. 10. In the...Masumoto. I Mat. Sci. 12 (1977) 1927, [IgI T M Ha.es. J. W Allen. J. Tauc . B. C. Giessen and J. J. Hauser. Phys. Re. Lett. 41 i197s) 1282 [191 J

  18. Coaxial inverted geometry transistor having buried emitter

    NASA Technical Reports Server (NTRS)

    Hruby, R. J.; Cress, S. B.; Dunn, W. R. (Inventor)

    1973-01-01

    The invention relates to an inverted geometry transistor wherein the emitter is buried within the substrate. The transistor can be fabricated as a part of a monolithic integrated circuit and is particularly suited for use in applications where it is desired to employ low actuating voltages. The transistor may employ the same doping levels in the collector and emitter, so these connections can be reversed.

  19. Buried caldera of mauna kea volcano, hawaii.

    PubMed

    Porter, S C

    1972-03-31

    An elliptical caldera (2.1 by 2.8 kilometers) at the summit of Mauna Kea volcano is inferred to lie buried beneath hawaiite lava flows and pyroclastic cones at an altitude of approximately 3850 meters. Stratigraphic relationships indicate that hawaiite eruptions began before a pre-Wisconsin period of ice-cap glaciation and that the crest of the mountain attained its present altitude and gross form during a glaciation of probable Early Wisconsin age.

  20. Breakdown mechanism in buried silicon oxide films

    NASA Astrophysics Data System (ADS)

    Mayo, Santos; Suehle, John S.; Roitman, Peter

    1993-09-01

    Charge injection leading to catastrophic breakdown has been used to study the dielectric properties of the buried oxide layer in silicon implanted with high-energy oxygen ions. Current versus gate bias, current versus time, and capacitance versus gate bias were used to characterize, at various temperatures, MOS metal-oxide-semiconductor capacitors with areas in the 1×10-4-1×10-2 cm2 range fabricated with commercially available single- or triple-implant separation by implanted oxygen silicon wafers. The data show that injected charge accumulates in the buried oxide at donorlike oxide traps ultimately leading to catastrophic breakdown. Both Poole-Frenkel and Fowler-Nordheim conduction, as well as impact-ionization mechanisms, have been identified in the oxide. The charge and field to breakdown in the best buried oxides are, respectively, near 1 C cm-2 and 10 MV cm-1, similar to the thermally grown oxide parameters. Cumulative distributions of these parameters measured over a large number of capacitors show that the frequency of breakdown events caused by extrinsic defects is scaled with the capacitor area. Intrinsic and extrinsic defect distributions are broader than with thermally grown oxides.

  1. DOE complex buried waste characterization assessment

    SciTech Connect

    Kaae, P.S.; Holter, G.M.; Garrett, S.M.K.

    1993-01-01

    The work described in this report was conducted by Pacific Northwest Laboratory to provide information to the Buried Waste Integrated Demonstration (BWID) program. The information in this report is intended to provide a complex-wide planning base for th.e BWID to ensure that BWID activities are appropriately focused to address the range of remediation problems existing across the US Department of Energy (DOE) complex. This report contains information characterizing the 2.1 million m[sup 3] of buried and stored wastes and their associated sites at six major DOE facilities. Approximately 85% of this waste is low-level waste, with about 12% TRU or TRU mixed waste; the remaining 3% is low-level mixed waste. In addition, the report describes soil contamination sites across the complex. Some of the details that would be useful in further characterizing the buried wastes and contaminated soil sites across the DOE complex are either unavailable or difficult to locate. Several options for accessing this information and/or improving the information that is available are identified in the report. This document is a companion to Technology Needs for Remediation: Hanford and Other DOE Sites, PNL-8328 (Stapp 1993).

  2. The Stabilization of Amorphous Zopiclone in an Amorphous Solid Dispersion.

    PubMed

    Milne, Marnus; Liebenberg, Wilna; Aucamp, Marique

    2015-10-01

    Zopiclone is a poorly soluble psychotherapeutic agent. The aim of this study was to prepare and characterize an amorphous form of zopiclone as well as the characterization and performance of a stable amorphous solid dispersion. The amorphous form was prepared by the well-known method of quench-cooling of the melt. The solid dispersion was prepared by a solvent evaporation method of zopiclone, polyvinylpyrrolidone-25 (PVP-25), and methanol, followed by freeze-drying. The physico-chemical properties and stability of amorphous zopiclone and the solid dispersion was studied using differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), hot-stage microscopy (HSM), X-ray diffractometry (XRD), solubility, and dissolution studies. The zopiclone amorphous solid-state form was determined to be a fragile glass; it was concluded that the stability of the amorphous form is influenced by both temperature and water. Exposure of amorphous zopiclone to moisture results in rapid transformation of the amorphous form to the crystalline dihydrated form. In comparison, the amorphous solid dispersion proved to be more stable with increased aqueous solubility.

  3. Transverse seismic analysis of buried pipelines

    SciTech Connect

    Mavridis, G.A.; Pitilakis, K.D.

    1995-12-31

    The objective of this study is to develop an analytical procedure for calculating upper bounds for stresses and strains for the case of the transverse seismic shaking of continuous buried pipelines taking into account the soil-pipeline interaction effects. A sensibility analysis of some critical parameters is performed. The influence of various parameters such as the apparent propagation velocity, the frequency content of the seismic ground excitation, the dynamic soil properties, the pipe`s material and size, on the ratio of the pipe to ground displacements amplitudes and consequently to the induced pipe strains, are studied parametrically.

  4. Buried waste integrated demonstration configuration management plan

    SciTech Connect

    Cannon, P.G.

    1992-02-01

    This document defines plans for the configuration management requirements for the Buried Waste Integrated Demonstration (BWID) Program. Since BWID is managed programmatically by the Waste Technology Development Department (WTDD), WTDD Program Directive (PD) 1.5 (Document Preparation, Review, Approval, Publication, Management and Change Control) is to be followed for all internal EG G Idaho, Inc., BWID programmatic documentation. BWID documentation generated by organizations external to EG G Idaho is not covered by this revision of the Configuration Management Plan (CMP), but will be addressed in subsequent revisions.

  5. Buried waste integrated demonstration configuration management plan

    SciTech Connect

    Cannon, P.G.

    1992-02-01

    This document defines plans for the configuration management requirements for the Buried Waste Integrated Demonstration (BWID) Program. Since BWID is managed programmatically by the Waste Technology Development Department (WTDD), WTDD Program Directive (PD) 1.5 (Document Preparation, Review, Approval, Publication, Management and Change Control) is to be followed for all internal EG&G Idaho, Inc., BWID programmatic documentation. BWID documentation generated by organizations external to EG&G Idaho is not covered by this revision of the Configuration Management Plan (CMP), but will be addressed in subsequent revisions.

  6. Fabrication of Buried Nanochannels From Nanowire Patterns

    NASA Technical Reports Server (NTRS)

    Choi, Daniel; Yang, Eui-Hyeok

    2007-01-01

    A method of fabricating channels having widths of tens of nanometers in silicon substrates and burying the channels under overlying layers of dielectric materials has been demonstrated. With further refinement, the method might be useful for fabricating nanochannels for manipulation and analysis of large biomolecules at single-molecule resolution. Unlike in prior methods, burying the channels does not involve bonding of flat wafers to the silicon substrates to cover exposed channels in the substrates. Instead, the formation and burying of the channels are accomplished in a more sophisticated process that is less vulnerable to defects in the substrates and less likely to result in clogging of, or leakage from, the channels. In this method, the first step is to establish the channel pattern by forming an array of sacrificial metal nanowires on an SiO2-on-Si substrate. In particular, the wire pattern is made by use of focused-ion-beam (FIB) lithography and a subsequent metallization/lift-off process. The pattern of metal nanowires is then transferred onto the SiO2 layer by reactive-ion etching, which yields sacrificial SiO2 nanowires covered by metal. After removal of the metal covering the SiO2 nanowires, what remains are SiO2 nanowires on an Si substrate. Plasma-enhanced chemical vapor deposition (PECVD) is used to form a layer of a dielectric material over the Si substrate and over the SiO2 wires on the surface of the substrate. FIB milling is then performed to form trenches at both ends of each SiO2 wire. The trenches serve as openings for the entry of chemicals that etch SiO2 much faster than they etch Si. Provided that the nanowires are not so long that the diffusion of the etching chemicals is blocked, the sacrificial SiO2 nanowires become etched out from between the dielectric material and the Si substrate, leaving buried channels. At the time of reporting the information for this article, channels 3 m long, 20 nm deep, and 80 nm wide (see figure) had been

  7. ENDEAVOUR to understand EUV buried defect printability

    NASA Astrophysics Data System (ADS)

    Seki, Kazunori; Isogawa, Takeshi; Kagawa, Masayuki; Akima, Shinji; Kodera, Yutaka; Badger, Karen; Qi, Zhengqing J.; Lawliss, Mark; Rankin, Jed; Bonam, Ravi

    2015-07-01

    NAP-PD (Native Acting Phase - Programmed Defects), otherwise known as buried program defects, with attributes very similar to native defects, are successfully fabricated using a high accuracy overlay technique. The defect detectability and visibility are analyzed with conventional phase contrast blank inspection @193 nm wavelength, pattern inspection @193 nm wavelength and SEM. The mask is also printed on wafer and printability is discussed. Finally, the inspection sensitivity and wafer printability are compared, leading to the observation that the current blank and pattern inspection sensitivity is not enough to detect all of the printable defects.

  8. Substrate discrimination in burying beetles, Nicrophorus orbicollis (Coleoptera: Silphidae)

    USGS Publications Warehouse

    Muths, Erin Louise

    1991-01-01

    Burying beetles Nicrophorus orbicollis (Coleoptera: Silphidae) secure and bury small vertebrate carcasses as a food resource for their offspring and themselves. Burial may take place at the point of carcass discovery or at some distance from that site. Burying beetles were tested to determine if they discriminate between different substrates when burying a carcass. Three substrates were presented simultaneously. Substrate one contained soil from typical beetle habitat; substrates two and three contained 2:1 and 5:1 ratios, respectively, of soil and a senescent prairie grass (Panicum virgatum), which added a bulk structural component to the soil. Beetles generally moved and buried the carcass within 24 hours. Results for both paired and individual trials suggest that burying beetles discriminate between substrates, preferring substrates with added bulk over those without.

  9. Sensor system for buried waste containment sites

    DOEpatents

    Smith, Ann Marie; Gardner, Bradley M.; Kostelnik, Kevin M.; Partin, Judy K.; Lancaster, Gregory D.; Pfeifer, May Catherine

    2000-01-01

    A sensor system is disclosed for a buried waste containment site having a bottom wall barrier and/or sidewall barriers, for containing hazardous waste. The sensor system includes one or more sensor devices disposed in one or more of the barriers for detecting a physical parameter either of the barrier itself or of the physical condition of the surrounding soils and buried waste, and for producing a signal representing the physical parameter detected. Also included is a signal processor for receiving signals produced by the sensor device and for developing information identifying the physical parameter detected, either for sounding an alarm, displaying a graphic representation of a physical parameter detected on a viewing screen and/or a hard copy printout. The sensor devices may be deployed in or adjacent the barriers at the same time the barriers are deployed and may be adapted to detect strain or cracking in the barriers, leakage of radiation through the barriers, the presence and leaking through the barriers of volatile organic compounds, or similar physical conditions.

  10. Compensated amorphous silicon solar cell

    DOEpatents

    Carlson, David E.

    1980-01-01

    An amorphous silicon solar cell incorporates a region of intrinsic hydrogenated amorphous silicon fabricated by a glow discharge wherein said intrinsic region is compensated by P-type dopants in an amount sufficient to reduce the space charge density of said region under illumination to about zero.

  11. System and method for removal of buried objects

    DOEpatents

    Alexander, Robert G.; Crass, Dennis; Grams, William; Phillips, Steven J.; Riess, Mark

    2008-06-03

    The present invention is a system and method for removal of buried objects. According to one embodiment of the invention, a crane with a vibrator casing driver is used to lift and suspend a large diameter steel casing over the buried object. Then the casing is driven into the ground by the vibratory driver until the casing surrounds the buried object. Then the open bottom of the casing is sealed shut by injecting grout into the ground within the casing near its bottom. When the seal has cured and hardened, the top of the casing is lifted to retrieve the casing, with the buried object inside, from the ground.

  12. Multi channel FM reflection profiler for buried pipeline surveying

    SciTech Connect

    Schock, S.G.; LeBlanc, L.R.

    1996-12-31

    A towed multi-channel FM acoustic reflection profiler has been developed for locating and generating images of buried objects. One significant application of this sonar is buried pipeline surveying. The multi-channel reflection profiler uses 16 line arrays mounted in a towed vehicle to determine the position and burial depth of an 18 inch steel pipe filled with concrete buried under 1.5 meters of sand. This sonar will allow a survey vessel to continuously track a buried pipeline providing a continuous record of pipe burial depth and position.

  13. Compensated amorphous silicon solar cell

    DOEpatents

    Devaud, Genevieve

    1983-01-01

    An amorphous silicon solar cell including an electrically conductive substrate, a layer of glow discharge deposited hydrogenated amorphous silicon over said substrate and having regions of differing conductivity with at least one region of intrinsic hydrogenated amorphous silicon. The layer of hydrogenated amorphous silicon has opposed first and second major surfaces where the first major surface contacts the electrically conductive substrate and an electrode for electrically contacting the second major surface. The intrinsic hydrogenated amorphous silicon region is deposited in a glow discharge with an atmosphere which includes not less than about 0.02 atom percent mono-atomic boron. An improved N.I.P. solar cell is disclosed using a BF.sub.3 doped intrinsic layer.

  14. Bulk amorphous materials

    SciTech Connect

    Schwarz, R.B.; Archuleta, J.I.; Sickafus, K.E.

    1998-12-01

    This is the final report for a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this work was to develop the competency for the synthesis of novel bulk amorphous alloys. The authors researched their synthesis methods and alloy properties, including thermal stability, mechanical, and transport properties. The project also addressed the development of vanadium-spinel alloys for structural applications in hostile environments, the measurement of elastic constants and thermal expansion in single-crystal TiAl from 300 to 750 K, the measurement of elastic constants in gallium nitride, and a study of the shock-induced martensitic transformations in NiTi alloys.

  15. Piezoelectric radiofrequency transducers as passive buried sensors

    NASA Astrophysics Data System (ADS)

    Rétornaz, T.; Friedt, J.-M.; Alzuaga, S.; Baron, T.; Lebrasseur, É.; Martin, G.; Laroche, T.; Ballandras, S.; Griselin, M.; Simonnet, J.-P.

    2012-09-01

    We demonstrate that single-piezoelectric substrate-based acoustic transducers act as ideal sensors for probing with various RADAR strategies. Because these sensors are intrinsically passive devices working in the radiofrequency range, they exhibit improved interrogation range and robustness with respect to silicon-based radio frequency identification tags. Both wideband (acoustic delay lines) and narrowband (acoustic resonators) transducers are shown to be compatible with pulse-mode and frequency-modulated continuous-wave RADAR strategies, respectively. We particularly focus on the ground-penetrating RADAR (GPR) application in which the lack of local energy source makes these sensors suitable candidates for buried applications in roads, building or civil engineering monitoring. A novel acoustic sensor concept - high-overtone bulk acoustic resonator - is especially suited as sensor interrogated by a wide range of antenna set, as demonstrated with GPR units working in the 100 and 200 MHz range.

  16. Buried waste integrated demonstration technology integration process

    SciTech Connect

    Ferguson, J.S.; Ferguson, J.E.

    1992-04-01

    A Technology integration Process was developed for the Idaho National Energy Laboratories (INEL) Buried Waste Integrated Demonstration (BWID) Program to facilitate the transfer of technology and knowledge from industry, universities, and other Federal agencies into the BWID; to successfully transfer demonstrated technology and knowledge from the BWID to industry, universities, and other Federal agencies; and to share demonstrated technologies and knowledge between Integrated Demonstrations and other Department of Energy (DOE) spread throughout the DOE Complex. This document also details specific methods and tools for integrating and transferring technologies into or out of the BWID program. The document provides background on the BWID program and technology development needs, demonstrates the direction of technology transfer, illustrates current processes for this transfer, and lists points of contact for prospective participants in the BWID technology transfer efforts. The Technology Integration Process was prepared to ensure compliance with the requirements of DOE`s Office of Technology Development (OTD).

  17. Buried waste integrated demonstration technology integration process

    SciTech Connect

    Ferguson, J.S.; Ferguson, J.E.

    1992-04-01

    A Technology integration Process was developed for the Idaho National Energy Laboratories (INEL) Buried Waste Integrated Demonstration (BWID) Program to facilitate the transfer of technology and knowledge from industry, universities, and other Federal agencies into the BWID; to successfully transfer demonstrated technology and knowledge from the BWID to industry, universities, and other Federal agencies; and to share demonstrated technologies and knowledge between Integrated Demonstrations and other Department of Energy (DOE) spread throughout the DOE Complex. This document also details specific methods and tools for integrating and transferring technologies into or out of the BWID program. The document provides background on the BWID program and technology development needs, demonstrates the direction of technology transfer, illustrates current processes for this transfer, and lists points of contact for prospective participants in the BWID technology transfer efforts. The Technology Integration Process was prepared to ensure compliance with the requirements of DOE's Office of Technology Development (OTD).

  18. Landslide Buries Valley of the Geysers

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Geysers are a rare natural phenomena found only in a few places, such as New Zealand, Iceland, the United States (Yellowstone National Park), and on Russia's far eastern Kamchatka Peninsula. On June 3, 2007, one of these rare geyser fields was severely damaged when a landslide rolled through Russia's Valley of the Geysers. The landslide--a mix of mud, melting snow, trees, and boulders--tore a scar on the land and buried a number of geysers, thermal pools, and waterfalls in the valley. It also blocked the Geyser River, causing a new thermal lake to pool upstream. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this infrared-enhanced image on June 11, 2007, a week after the slide. The image shows the valley, the landslide, and the new thermal lake. Even in mid-June, just days from the start of summer, the landscape is generally covered in snow, though the geologically heated valley is relatively snow free. The tree-covered hills are red (the color of vegetation in this false-color treatment), providing a strong contrast to the aquamarine water and the gray-brown slide. According to the Russian News and Information Agency (RIA) [English language], the slide left a path roughly a kilometer and a half (one mile) long and 200 meters (600 feet) wide. Within hours of the landslide, the water in the new lake inundated a number of additional geysers. The geysers directly buried under the landslide now lie under as much as 60 meters (180 feet) of material, according to RIA reports. It is unlikely that the geysers will be able to force a new opening through this thick layer, adds RIA. Among those directly buried is Pervenets (Firstborn), the first geyser found in the valley, in 1941. Other geysers, such as the Bolshoi (Greater) and Maly (Lesser) Geysers, were silenced when buried by water building up behind the new natural dam. According to Vladimir and Andrei Leonov of the Russian Federation Institute of

  19. Acute buried bumper syndrome: an endoscopic peg tube salvage approach.

    PubMed

    Bhat, Ganesh; Suvarna, Deepak; Pai, Cannanore Ganesh

    2010-05-01

    Acute buried bumper syndrome is an uncommon complication of percutaneous endoscopic gastrostomy (PEG) tube placement. If not recognized and treated appropriately, it can lead to serious complications including death. We report a case of an acute buried bumper syndrome, successfully managed with PEG tube repositioning through the original tract, without the need of replacement.

  20. Buried Oxide Densification for Low Power, Low Voltage CMOS Applications

    NASA Technical Reports Server (NTRS)

    Allen, L. P.; Anc, M. J.; Dolan, B.; Jiao, J.; Guss, B.; Seraphin, S.; Liu, S. T.; Jenkins, W.

    1998-01-01

    Special technology and circuit architecture are of growing interest for implementation of circuits which operate at low supply voltages and consume low power levels without sacrificing performance[1]. Use of thin buried oxide SOI substrates is a primary approach to simultaneously achieve these goals. A significant aspect regarding SIMOX SOI for low voltage, low power applications is the reliability and performance of the thin buried oxide. In addition, when subjected to high total dose irradiation, the silicon islands within the BOX layer of SIMOX can store charges and significantly effect the back channel threshold voltages of devices. Thus, elimination of the islands within the buried oxide (BOX) layer is preferred in order to prevent leakage through these conductive islands and charge build-up within the buried oxide layer. A differential (2-step) ramp rate as applied to full and 100 nm BOX SIMOX was previously reported to play a significant role in the stoichiometry and island formation within the buried layer[2]. This paper focus is on the properties of a thin (120nm) buried oxide as a function of the anneal ramp rate and the temperature of anneal. In this research, we have found an improvement in the buried oxide stoichiometry with the use of a slower, singular ramp rate for specified thin buried oxides, with slower ramp rates and higher temperatures of anneal suggested for reducing the presence of Si islands within the BOX layer.

  1. Containerless processing of amorphous ceramics

    NASA Technical Reports Server (NTRS)

    Weber, J. K. Richard; Krishnan, Shankar; Schiffman, Robert A.; Nordine, Paul C.

    1990-01-01

    The absence of gravity allows containerless processing of materials which could not otherwise be processed. High melting point, hard materials such as borides, nitrides, and refractory metals are usually brittle in their crystalline form. The absence of dislocations in amorphous materials frequently endows them with flexibility and toughness. Systematic studies of the properties of many amorphous materials have not been carried out. The requirements for their production is that they can be processed in a controlled way without container interaction. Containerless processing in microgravity could permit the control necessary to produce amorphous forms of hard materials.

  2. Predicting arsenic concentrations in porewaters of buried uranium mill tailings

    SciTech Connect

    Langmuir, D.; Mahoney, J.; MacDonald, A.; Rowson, J.

    1999-10-01

    The proposed JEB Tailings Management Facility (TMF) to be emplaced below the groundwater table in northern Saskatchewan, Canada, will contain uranium mill tailings from McClean Lake, Midwest and Cigar Lake ore bodies, which are high in arsenic (up to 10%) and nickel (up to 5%). A serious concern is the possibility that high arsenic and nickel concentrations may be released from the buried tailings, contaminating adjacent groundwaters and a nearby lake. Laboratory tests and geochemical modeling were performed to examine ways to reduce the arsenic and nickel concentrations in TMF porewaters so as to minimize such contamination from tailings buried for 50 years and longer. The tests were designed to mimic conditions in the mill neutralization circuit (3 hr tests at 25 C), and in the TMF after burial (5--49 day aging tests). The aging tests were run at 50, 25 and 4 C (the temperature in the TMF). In order to optimize the removal of arsenic by adsorption and precipitation, ferric sulfate was added to tailings raffinates having Fe/As ratios of less than 3--5. The acid raffinates were then neutralized by addition of slaked lime to nominal pH values of 7, 8, or 9. Analysis and modeling of the test results showed that with slaked lime addition to acid tailings raffinates, relatively amorphous scorodite (ferric arsenate) precipitates near pH 1, and is the dominant form of arsenate in slake limed tailings solids except those high in Ni and As and low in Fe, in which cabrerite-annabergite (Ni, Mg, Fe(II) arsenate) may also precipitate near pH 5--6. In addition to the arsenate precipitates, smaller amounts of arsenate are also adsorbed onto tailings solids. The aging tests showed that after burial of the tailings, arsenic concentrations may increase with time from the breakdown of the arsenate phases (chiefly scorodite). However, the tests indicate that the rate of change decreases and approaches zero after 72 hrs at 25 C, and may equal zero at all times in the TMF at 4 C

  3. DOE complex buried waste characterization assessment. Buried Waste Integrated Demonstration Program

    SciTech Connect

    Kaae, P.S.; Holter, G.M.; Garrett, S.M.K.

    1993-01-01

    The work described in this report was conducted by Pacific Northwest Laboratory to provide information to the Buried Waste Integrated Demonstration (BWID) program. The information in this report is intended to provide a complex-wide planning base for th.e BWID to ensure that BWID activities are appropriately focused to address the range of remediation problems existing across the US Department of Energy (DOE) complex. This report contains information characterizing the 2.1 million m{sup 3} of buried and stored wastes and their associated sites at six major DOE facilities. Approximately 85% of this waste is low-level waste, with about 12% TRU or TRU mixed waste; the remaining 3% is low-level mixed waste. In addition, the report describes soil contamination sites across the complex. Some of the details that would be useful in further characterizing the buried wastes and contaminated soil sites across the DOE complex are either unavailable or difficult to locate. Several options for accessing this information and/or improving the information that is available are identified in the report. This document is a companion to Technology Needs for Remediation: Hanford and Other DOE Sites, PNL-8328 (Stapp 1993).

  4. Amorphous and Ultradisperse Crystalline Materials,

    DTIC Science & Technology

    The book sums up experimental and theoretical findings on amorphous and ultradisperse crystalline materials , massive and film types. Present-day... crystalline materials of metallic systems are presented. Emphasis is placed on inorganic film materials.

  5. Fabrication of amorphous diamond films

    DOEpatents

    Falabella, S.

    1995-12-12

    Amorphous diamond films having a significant reduction in intrinsic stress are prepared by biasing a substrate to be coated and depositing carbon ions thereon under controlled temperature conditions. 1 fig.

  6. Characterization Techniques for Amorphous Alloys

    NASA Astrophysics Data System (ADS)

    Carow-Watamura, U.; Louzguine, D. V.; Takeuchi, A.

    This document is part of Part 2 http://dx.doi.org/10.1007/9getType="URL"/> 'Systems from B-Be-Fe to Co-W-Zr' of Subvolume B 'Physical Properties of Ternary Amorphous Alloys' of Volume 37 'Phase Diagrams and Physical Properties of Nonequilibrium Alloys' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains the Chapter '2 Characterization Techniques for Amorphous Alloys' with the content:

  7. Amorphous metal alloy and composite

    DOEpatents

    Wang, Rong; Merz, Martin D.

    1985-01-01

    Amorphous metal alloys of the iron-chromium and nickel-chromium type have excellent corrosion resistance and high temperature stability and are suitable for use as a protective coating on less corrosion resistant substrates. The alloys are stabilized in the amorphous state by one or more elements of titanium, zirconium, hafnium, niobium, tantalum, molybdenum, and tungsten. The alloy is preferably prepared by sputter deposition.

  8. Dual-band infrared capabilities for imaging buried object sites

    SciTech Connect

    Del Grande, N.K.; Durbin, P.F.; Gorvad, M.R.; Perkins, D.E.; Clark, G.A.; Hernandez, J.E.; Sherwood, R.J.

    1993-04-02

    We discuss dual-band infrared (DBIR) capabilities for imaging buried object sizes. We identify physical features affecting thermal contrast needed to distinguish buried object sites from undisturbed sites or surface clutter. Apart from atmospheric transmission and system performance, these features include: object size, shape, and burial depth; ambient soil, disturbed soil and object site thermal diffusivity differences; surface temperature, emissivity, plant-cover, slope, albedo and roughness variations; weather conditions and measurement times. We use good instrumentation to measure the time-varying temperature differences between buried object sites and undisturbed soil sites. We compare near surface soil temperature differences with radiometric infrared (IR) surface temperature differences recorded at 4.7 {plus_minus} 0.4 {mu}m and at 10.6 {plus_minus} 1.0 {mu}m. By producing selective DBIR image ratio maps, we distinguish temperature-difference patterns from surface emissivity effects. We discuss temperature differences between buried object sites, filled hole site (without buried objects), cleared (undisturbed) soil sites, and grass-covered sites (with and without different types of surface clutter). We compare temperature, emissivity-ratio, visible and near-IR reflectance signatures of surface objects, leafy plants and sod. We discuss the physical aspects of environmental, surface and buried target features affecting interpretation of buried targets, surface objects and natural backgrounds.

  9. Hydrogenated amorphous silicon photonics

    NASA Astrophysics Data System (ADS)

    Narayanan, Karthik

    2011-12-01

    Silicon Photonics is quickly proving to be a suitable interconnect technology for meeting the future goals of on-chip bandwidth and low power requirements. However, it is not clear how silicon photonics will be integrated into CMOS chips, particularly microprocessors. The issue of integrating photonic circuits into electronic IC fabrication processes to achieve maximum flexibility and minimum complexity and cost is an important one. In order to minimize usage of chip real estate, it will be advantageous to integrate in three-dimensions. Hydrogenated amorphous silicon (a-Si:H) is emerging as a promising material for the 3-D integration of silicon photonics for on-chip optical interconnects. In addition, a-Si:H film can be deposited using CMOS compatible low temperature plasma-enhanced chemical vapor deposition (PECVD) process at any point in the fabrication process allowing maximum flexibility and minimal complexity. In this thesis, we demonstrate a-Si:H as a high performance alternate platform to crystalline silicon, enabling backend integration of optical interconnects in a hybrid photonic-electronic network-on-chip architecture. High quality passive devices are fabricated on a low-loss a-Si:H platform enabling wavelength division multiplexing schemes. We demonstrate a broadband all-optical modulation scheme based on free-carrier absorption effect, which can enable compact electro-optic modulators in a-Si:H. Furthermore, we comprehensively characterize the optical nonlinearities in a-Si:H and observe that a-Si:H exhibits enhanced nonlinearities as compared to crystalline silicon. Based on the enhanced nonlinearities, we demonstrate low-power four-wave mixing in a-Si:H waveguides enabling high speed all-optical devices in an a-Si:H platform. Finally, we demonstrate a novel data encoding scheme using thermal and all-optical tuning of silicon waveguides, increasing the spectral efficiency in an interconnect link.

  10. Amorphous carbon for photovoltaics

    NASA Astrophysics Data System (ADS)

    Risplendi, Francesca; Grossman, Jeffrey C.

    2015-03-01

    All-carbon solar cells have attracted attention as candidates for innovative photovoltaic devices. Carbon-based materials such as graphene, carbon nanotubes (CNT) and amorphous carbon (aC) have the potential to present physical properties comparable to those of silicon-based materials with advantages such as low cost and higher thermal stability.In particular a-C structures are promising systems in which both sp2 and sp3 hybridization coordination are present in different proportions depending on the specific density, providing the possibility of tuning their optoelectronic properties and achieving comparable sunlight absorption to aSi. In this work we employ density functional theory to design suitable device architectures, such as bulk heterojunctions (BHJ) or pn junctions, consisting of a-C as the active layer material.Regarding BHJ, we study interfaces between aC and C nanostructures (such as CNT and fullerene) to relate their optoelectronic properties to the stoichiometry of aC. We demonstrate that the energy alignment between the a-C mobility edges and the occupied and unoccupied states of the CNT or C60 can be widely tuned by varying the aC density to obtain a type II interface.To employ aC in pn junctions we analyze the p- and n-type doping of a-C focusingon an evaluation of the Fermi level and work function dependence on doping.Our results highlight promising features of aC as the active layer material of thin-film solar cells.

  11. Compact Buried Ducts in a Hot-Humid Climate House

    SciTech Connect

    Mallay, Dave

    2016-01-07

    "9A system of compact, buried ducts provides a high-performance and cost-effective solution for delivering conditioned air throughout the building. This report outlines research activities that are expected to facilitate adoption of compact buried duct systems by builders. The results of this research would be scalable to many new house designs in most climates and markets, leading to wider industry acceptance and building code and energy program approval. The primary research question with buried ducts is potential condensation at the outer jacket of the duct insulation in humid climates during the cooling season. Current best practices for buried ducts rely on encapsulating the insulated ducts with closed-cell spray polyurethane foam insulation to control condensation and improve air sealing. The encapsulated buried duct concept has been analyzed and shown to be effective in hot-humid climates. The purpose of this project is to develop an alternative buried duct system that performs effectively as ducts in conditioned space - durable, energy efficient, and cost-effective - in a hot-humid climate (IECC warm-humid climate zone 3A) with three goals that distinguish this project: 1) Evaluation of design criteria for buried ducts that use common materials and do not rely on encapsulation using spray foam or disrupt traditional work sequences; 2) Establishing design criteria for compact ducts and incorporate those with the buried duct criteria to further reduce energy losses and control installed costs; 3) Developing HVAC design guidance for performing accurate heating and cooling load calculations for compact buried ducts.

  12. Odor analysis of decomposing buried human remains

    SciTech Connect

    Vass, Arpad Alexander; Smith, Rob R; Thompson, Cyril V; Burnett, Michael N; Dulgerian, Nishan; Eckenrode, Brian A

    2008-01-01

    This study, conducted at the University of Tennessee's Anthropological Research Facility (ARF), lists and ranks the primary chemical constituents which define the odor of decomposition of human remains as detected at the soil surface of shallow burial sites. Triple sorbent traps were used to collect air samples in the field and revealed eight major classes of chemicals which now contain 478 specific volatile compounds associated with burial decomposition. Samples were analyzed using gas chromatography-mass spectrometry (GC-MS) and were collected below and above the body, and at the soil surface of 1.5-3.5 ft. (0.46-1.07 m) deep burial sites of four individuals over a 4-year time span. New data were incorporated into the previously established Decompositional Odor Analysis (DOA) Database providing identification, chemical trends, and semi-quantitation of chemicals for evaluation. This research identifies the 'odor signatures' unique to the decomposition of buried human remains with projected ramifications on human remains detection canine training procedures and in the development of field portable analytical instruments which can be used to locate human remains in shallow burial sites.

  13. Buried nanoantenna arrays: versatile antireflection coating.

    PubMed

    Kabiri, Ali; Girgis, Emad; Capasso, Federico

    2013-01-01

    Reflection is usually a detrimental phenomenon in many applications such as flat-panel-displays, solar cells, photodetectors, infrared sensors, and lenses. Thus far, to control and suppress the reflection from a substrate, numerous techniques including dielectric interference coatings, surface texturing, adiabatic index matching, and scattering from plasmonic nanoparticles have been investigated. A new technique is demonstrated to manage and suppress reflection from lossless and lossy substrates. It provides a wider flexibility in design versus previous methods. Reflection from a surface can be suppressed over a narrowband, wideband, or multiband frequency range. The antireflection can be dependent or independent of the incident wave polarization. Moreover, antireflection at a very wide incidence angle can be attained. The reflection from a substrate is controlled by a buried nanoantenna array, a structure composed of (1) a subwavelength metallic array and (2) a dielectric cover layer referred to as a superstrate. The material properties and thickness of the superstrate and nanoantennas' geometry and periodicity control the phase and intensity of the wave circulating inside the superstrate cavity. A minimum reflectance of 0.02% is achieved in various experiments in the mid-infrared from a silicon substrate. The design can be integrated in straightforward way in optical devices. The proposed structure is a versatile AR coating to optically impedance matches any substrate to free space in selected any narrow and broadband spectral response across the entire visible and infrared spectrum.

  14. Buried waste containment system materials. Final Report

    SciTech Connect

    Weidner, J.R.; Shaw, P.G.

    1997-10-01

    This report describes the results of a test program to validate the application of a latex-modified cement formulation for use with the Buried Waste Containment System (BWCS) process during a proof of principle (POP) demonstration. The test program included three objectives. One objective was to validate the barrier material mix formulation to be used with the BWCS equipment. A basic mix formula for initial trials was supplied by the cement and latex vendors. The suitability of the material for BWCS application was verified by laboratory testing at the Idaho National Engineering and Environmental Laboratory (INEEL). A second objective was to determine if the POP BWCS material emplacement process adversely affected the barrier material properties. This objective was met by measuring and comparing properties of material prepared in the INEEL Materials Testing Laboratory (MTL) with identical properties of material produced by the BWCS field tests. These measurements included hydraulic conductivity to determine if the material met the US Environmental Protection Agency (EPA) requirements for barriers used for hazardous waste sites, petrographic analysis to allow an assessment of barrier material separation and segregation during emplacement, and a set of mechanical property tests typical of concrete characterization. The third objective was to measure the hydraulic properties of barrier material containing a stop-start joint to determine if such a feature would meet the EPA requirements for hazardous waste site barriers.

  15. Odor analysis of decomposing buried human remains.

    PubMed

    Vass, Arpad A; Smith, Rob R; Thompson, Cyril V; Burnett, Michael N; Dulgerian, Nishan; Eckenrode, Brian A

    2008-03-01

    This study, conducted at the University of Tennessee's Anthropological Research Facility (ARF), lists and ranks the primary chemical constituents which define the odor of decomposition of human remains as detected at the soil surface of shallow burial sites. Triple sorbent traps were used to collect air samples in the field and revealed eight major classes of chemicals which now contain 478 specific volatile compounds associated with burial decomposition. Samples were analyzed using gas chromatography-mass spectrometry (GC-MS) and were collected below and above the body, and at the soil surface of 1.5-3.5 ft. (0.46-1.07 m) deep burial sites of four individuals over a 4-year time span. New data were incorporated into the previously established Decompositional Odor Analysis (DOA) Database providing identification, chemical trends, and semi-quantitation of chemicals for evaluation. This research identifies the "odor signatures" unique to the decomposition of buried human remains with projected ramifications on human remains detection canine training procedures and in the development of field portable analytical instruments which can be used to locate human remains in shallow burial sites.

  16. Buried plastic scintillator muon telescope (BATATA)

    NASA Astrophysics Data System (ADS)

    Alfaro, R.; de Donato, C.; D'Olivo, J. C.; Guzmán, A.; Medina-Tanco, G.; Moreno Barbosa, E.; Paic, G.; Patiño Salazar, E.; Salazar Ibarguen, H.; Sánchez, F. A.; Supanitsky, A. D.; Valdés-Galicia, J. F.; Vargas Treviño, A. D.; Vergara Limón, S.; Villaseñor, L. M.; Auger Collaboration

    2010-05-01

    Muon telescopes have multiple applications in the area of cosmic ray research. We are currently building such a detector with the objective of comparing the ground penetration of muon vs. electron-gamma signals originated in cosmic ray showers. The detector is composed by a set of three parallel dual-layer scintillator planes, buried at fixed depths ranging from 120 to 600g/cm2. Each layer is 4m2 and is composed by 49 rectangular strips of 4cm×2m, oriented at a 90∘ angle with respect to its companion layer, which gives an xy-coincidence pixel of 4×4cm2. The scintillators are MINOS extruded polystyrene strips, with an embedded Bicron BC92 wavelength shifting (WLS) fibers, of 1.5 mm in diameter. Light is collected by Hamamatsu H7546B multi-anode PMTs of 64 pixels. The front-end (FE) electronics works in counting mode and signals are transmitted to the surface DAQ stage using low-voltage differential signaling (LVDS). Any strip signal above threshold opens a GPS-tagged 2μs data collection window. Data, including signal and background, are acquired by a system of FPGA (Spartan 2E) boards and a single-board computer (TS7800).

  17. The problem of burying radioactive wastes containing transplutonium elements (TPE)

    SciTech Connect

    Bryzgalova, R.V.; Krivokhatskii, A.S.; Rogozin, Y.M.; Sinitsyna, G.S.

    1986-09-01

    This paper discusses the problem of burying radioactive wastes containing TPE. The most acceptable and developed method at present is that of disposal into continental, deep-lying, geological formatins. Based on an analysis of estimates of the thermal conditions on burying highly active wastes, including TPE concentrates, data on the filtration and sorption characteristics of rocks, estimates of the diffusion of radionuclide species capable of migrating, and taking into account the retention powers of rocks it is concluded that it is possible to bury such wastes in weakly permeable geological formations possessing shielding characteristics which ensure reliability and safety in burial.

  18. Computer vision and sensor fusion for detecting buried objects

    SciTech Connect

    Clark, G.A.; Hernandez, J.E.; Sengupta, S.K.; Sherwood, R.J.; Schaich, P.C.; Buhl, M.R.; Kane, R.J.; DelGrande, N.K.

    1992-10-01

    Given multiple images of the surface of the earth from dual-band infrared sensors, our system fuses information from the sensors to reduce the effects of clutter and improve the ability to detect buried or surface target sites. Supervised learning pattern classifiers (including neural networks,) are used. We present results of experiments to detect buried land mines from real data, and evaluate the usefulness of fusing information from multiple sensor types. The novelty of the work lies mostly in the combination of the algorithms and their application to the very important and currently unsolved problem of detecting buried land mines from an airborne standoff platform.

  19. Allotropic composition of amorphous carbon

    SciTech Connect

    Yastrebov, S. G. Ivanov-Omskii, V. I.

    2007-08-15

    Using the concept of an inhomogeneous broadening of spectral lines of the basic oscillators responsible for forming the spectrum, the experimental dependences of the dispersion of the imaginary part of permittivity are analyzed for amorphous carbon. It turned out that four types of oscillators contribute to this dependence. The first three types represent the electron transitions from the energy-spectrum ground state for {pi} and {sigma} electrons of amorphous carbon to an excited state. The fourth type is related to the absorption of electromagnetic radiation by free charge carriers. The absolute values of squared plasma frequencies of oscillators are estimated, and, using them, the relative fraction of sp{sup 2}-bonded atoms forming the amorphous-carbon skeleton is calculated. This estimate agrees closely with the theoretical predictions for amorphous carbon of the same density as the material under study. The dependence of the relative fraction of sp{sup 2}-bonded atoms contained in amorphous hydrogenised carbon on annealing temperature is determined. The developed method is also applied to the analysis of the normalized curve for the light extinction in the interstellar medium. The contribution to the extinction of two varieties of interstellar matter is detected.

  20. Carbon limitation patterns in buried and open urban streams

    EPA Science Inventory

    Urban streams alternate between darkened buried segments dominated by heterotrophic processes and lighted open segments dominated by autotrophic processes. We hypothesized that labile carbon leaking from autotrophic cells would reduce heterotrophic carbon limitation in open chan...

  1. Seismic analysis and design of buried pipelines for fault movement

    SciTech Connect

    Wang, L.R.L.; Yeh, Y.H.

    1984-06-01

    Lifelines, such as gas and oil transmission lines and water and sewer pipelines have been damaged heavily in recent earthquakes. The damages of these lifelines have caused major, catastrophic disruption of essential service to human needs. Large abrupt differential ground movements resulted at an active fault present one of the most severe earthquake effects on a buried pipeline system. Although simplified analysis procedures for buried pipelines across strike-slip fault zones causing tensive failure of the pipeline (called tensile strike-slip fault) have been proposed, the results are not accurate enough because of several assumptions involved. Furthermore, several other important failure mechanisms and parameters have not been investigated. This paper is to present the analysis procedures and results for buried pipeline subjected to tensile strike-slip fault after modifying some of the assumptions used previously. Based on the analysis results, this paper also discusses the design criteria for buried pipelines subjected to various fault movements.

  2. Data fusion for the detection of buried land mines

    SciTech Connect

    Clark, G.A.; Sengupta, S.K.; Schaich, P.C.; Sherwood, R.J.; Buhl, M.R.; Hernandez, J.E.; Kane, R.J.; Barth, M.J.; Fields, D.J.; Carter, M.R.

    1993-10-01

    The authors conducted experiments to demonstrate the enhanced delectability of buried land mines using sensor fusion techniques. Multiple sensors, including imagery, infrared imagery, and ground penetrating radar, have been used to acquire data on a number of buried mines and mine surrogates. The authors present this data along with a discussion of the application of sensor fusion techniques for this particular detection problem. The authors describe the data fusion architecture and discuss some relevant results of these classification methods.

  3. Compact Buried Ducts in a Hot-Humid Climate House

    SciTech Connect

    Mallay, D.

    2016-01-01

    A system of compact, buried ducts provides a high-performance and cost-effective solution for delivering conditioned air throughout the building. This report outlines research activities that are expected to facilitate adoption of compact buried duct systems by builders. The results of this research would be scalable to many new house designs in most climates and markets, leading to wider industry acceptance and building code and energy program approval.

  4. Centrifugal and Analytical Modeling of a Buried Flexible Culvert.

    DTIC Science & Technology

    1985-10-31

    INTRODUCTION 1.1 Introduction The complex problem of the reaction of a buried culvert to loads applied at the ground surface is studied using physical ...buckling (Allgood et al., 1968, Luscher 1966, Whitman et al., 1962). Since the failure mode of the culvert is controlled by the geometry and the...occur before the buckling failure in this case. Larsen (1977) analyzed the earth pressure around the buried concrete pipe by testing scale physical

  5. Decomposition of forest products buried in landfills

    SciTech Connect

    Wang, Xiaoming; Padgett, Jennifer M.; Powell, John S.; Barlaz, Morton A.

    2013-11-15

    Highlights: • This study tracked chemical changes of wood and paper in landfills. • A decomposition index was developed to quantify carbohydrate biodegradation. • Newsprint biodegradation as measured here is greater than previous reports. • The field results correlate well with previous laboratory measurements. - Abstract: The objective of this study was to investigate the decomposition of selected wood and paper products in landfills. The decomposition of these products under anaerobic landfill conditions results in the generation of biogenic carbon dioxide and methane, while the un-decomposed portion represents a biogenic carbon sink. Information on the decomposition of these municipal waste components is used to estimate national methane emissions inventories, for attribution of carbon storage credits, and to assess the life-cycle greenhouse gas impacts of wood and paper products. Hardwood (HW), softwood (SW), plywood (PW), oriented strand board (OSB), particleboard (PB), medium-density fiberboard (MDF), newsprint (NP), corrugated container (CC) and copy paper (CP) were buried in landfills operated with leachate recirculation, and were excavated after approximately 1.5 and 2.5 yr. Samples were analyzed for cellulose (C), hemicellulose (H), lignin (L), volatile solids (VS), and organic carbon (OC). A holocellulose decomposition index (HOD) and carbon storage factor (CSF) were calculated to evaluate the extent of solids decomposition and carbon storage. Samples of OSB made from HW exhibited cellulose plus hemicellulose (C + H) loss of up to 38%, while loss for the other wood types was 0–10% in most samples. The C + H loss was up to 81%, 95% and 96% for NP, CP and CC, respectively. The CSFs for wood and paper samples ranged from 0.34 to 0.47 and 0.02 to 0.27 g OC g{sup −1} dry material, respectively. These results, in general, correlated well with an earlier laboratory-scale study, though NP and CC decomposition measured in this study were higher than

  6. Decomposition of forest products buried in landfills.

    PubMed

    Wang, Xiaoming; Padgett, Jennifer M; Powell, John S; Barlaz, Morton A

    2013-11-01

    The objective of this study was to investigate the decomposition of selected wood and paper products in landfills. The decomposition of these products under anaerobic landfill conditions results in the generation of biogenic carbon dioxide and methane, while the un-decomposed portion represents a biogenic carbon sink. Information on the decomposition of these municipal waste components is used to estimate national methane emissions inventories, for attribution of carbon storage credits, and to assess the life-cycle greenhouse gas impacts of wood and paper products. Hardwood (HW), softwood (SW), plywood (PW), oriented strand board (OSB), particleboard (PB), medium-density fiberboard (MDF), newsprint (NP), corrugated container (CC) and copy paper (CP) were buried in landfills operated with leachate recirculation, and were excavated after approximately 1.5 and 2.5yr. Samples were analyzed for cellulose (C), hemicellulose (H), lignin (L), volatile solids (VS), and organic carbon (OC). A holocellulose decomposition index (HOD) and carbon storage factor (CSF) were calculated to evaluate the extent of solids decomposition and carbon storage. Samples of OSB made from HW exhibited cellulose plus hemicellulose (C+H) loss of up to 38%, while loss for the other wood types was 0-10% in most samples. The C+H loss was up to 81%, 95% and 96% for NP, CP and CC, respectively. The CSFs for wood and paper samples ranged from 0.34 to 0.47 and 0.02 to 0.27gOCg(-1) dry material, respectively. These results, in general, correlated well with an earlier laboratory-scale study, though NP and CC decomposition measured in this study were higher than previously reported.

  7. Record Blizzard Buries U.S. Northeast

    NASA Technical Reports Server (NTRS)

    2005-01-01

    After two days of blustery weather, the skies cleared over Massachusetts on January 24, 2005. Along with other northeastern U.S. states, Massachusetts was slammed with a powerful blizzard on January 22 and 23 that shut down travel and businesses and extinguished power. The storm brought record snow to many places, but Massachusetts topped the list. The cities of Salem and Plymouth were buried in 38 inches (96.5 cm) of snow, and strong winds created drifts up to seven feet (2 meters) high, according to the National Weather Service. For Boston, the storm was the fifth worst blizzard to hit the city since 1892, dumping 22.5 inches (57 cm) of snow in two days. Of that, 13.4 inches (34 cm) fell on January 23' the most snow to fall on the city in a single day since records began. These totals gave Boston nearly twice its average snowfall for January (the average is 13.5 inches, 34.3 cm), and over half its annual average snow of 41.8 inches (106 cm). This Moderate Resolution Imaging Spectroradiometer (MODIS) image, taken on January 24 by NASA's Terra satellite, shows the effects of the storm on Massachusetts and its southern neighbors, Connecticut (left) and Rhode Island (right). New York's Long Island is in the lower left corner of the image. The entire region is coated with snow, though clouds obscure the ground on the left side of the image. The snow was accompanied by powerful hurricane-force winds that helped create white-out conditions and large snowdrifts. The wind also churned ocean waters around Cape Cod, leaving them milky with sediment. NASA image courtesy the MODIS Rapid Response Team at NASA GSFC.

  8. Airblast environments from buried HE charges

    SciTech Connect

    Reichenbach, H.; Behrens, K.; Kuhl, A.

    1993-01-01

    Laboratory experiments were conducted to measure the airblast environment generated by the detonation of buried HE charges. Spherical 0.5-g charges of Nitropenta were used as the HE source. Three ground materials were used: (1) a porous, crushable grout (YTONG, {rho} = 0.4 g/cm{sup 3}); (2) a water-saturated grout ({rho} {approx_equal} 0.7 g/Cm{sup 3}) to investigate the effects of density increase; and (3) a clay-loam material ({rho} {approx_equal} 1.8 g/cm{sup 3}) to simulate some of the previous field tests conducted in clay. Diagnostics consisted of 13 flush-mounted pressure gauges, and single-frame schlieren photography. A special shock isolation system was used to eliminate the acceleration effects on the gauges that were induced by the cratering process. Analysis of the pressure measurements resulted in an experimental definition of the airblast environment as a function of ground range (GR) and depth-of-burst (DOB). Synthesis of these results allowed one to construct airblast DOB curves, similar to the airblast height-of-burst curves that we published previously for Nitropenta charges. Variables analyzed were: peak pressure, arrival time, positive phase duration and impulse. As in field tests, we found that the airblast waveforms changed character with increasing DOB. The crater characteristics (e.a., depth, radius and volume) were also measured. The cube-root-scaled crater volume was in qualitative agreement with data from field tests (e.g., charge weights up to 10{sup 4} lbs.). Since the present scaled results compare well with data from large-scale HE tests, we conclude that the present experimental technique provides a useful tool for parametric investigations of explosion effects in the laboratory.

  9. Nanostructures having crystalline and amorphous phases

    DOEpatents

    Mao, Samuel S; Chen, Xiaobo

    2015-04-28

    The present invention includes a nanostructure, a method of making thereof, and a method of photocatalysis. In one embodiment, the nanostructure includes a crystalline phase and an amorphous phase in contact with the crystalline phase. Each of the crystalline and amorphous phases has at least one dimension on a nanometer scale. In another embodiment, the nanostructure includes a nanoparticle comprising a crystalline phase and an amorphous phase. The amorphous phase is in a selected amount. In another embodiment, the nanostructure includes crystalline titanium dioxide and amorphous titanium dioxide in contact with the crystalline titanium dioxide. Each of the crystalline and amorphous titanium dioxide has at least one dimension on a nanometer scale.

  10. Amorphous-diamond electron emitter

    DOEpatents

    Falabella, Steven

    2001-01-01

    An electron emitter comprising a textured silicon wafer overcoated with a thin (200 .ANG.) layer of nitrogen-doped, amorphous-diamond (a:D-N), which lowers the field below 20 volts/micrometer have been demonstrated using this emitter compared to uncoated or diamond coated emitters wherein the emission is at fields of nearly 60 volts/micrometer. The silicon/nitrogen-doped, amorphous-diamond (Si/a:D-N) emitter may be produced by overcoating a textured silicon wafer with amorphous-diamond (a:D) in a nitrogen atmosphere using a filtered cathodic-arc system. The enhanced performance of the Si/a:D-N emitter lowers the voltages required to the point where field-emission displays are practical. Thus, this emitter can be used, for example, in flat-panel emission displays (FEDs), and cold-cathode vacuum electronics.

  11. Buried and Encapsulated Ducts, Jacksonville, Florida (Fact Sheet)

    SciTech Connect

    Not Available

    2013-11-01

    Ductwork installed in unconditioned attics can significantly increase the overall heating and cooling costs of residential buildings. In fact, estimated duct thermal losses for single-family residential buildings with ductwork installed in unconditioned attics range from 10% to 45%. In a study of three single-story houses in Florida, the Building America research team Consortium for Advanced Residential Buildings (CARB) investigated the strategy of using buried and/or encapsulated ducts (BED) to reduce duct thermal losses in existing homes. The BED strategy consists of burying ducts in loose-fill insulation and/or encapsulating them in closed cell polyurethane spray foam (ccSPF) insulation. There are three possible combinations of BED strategies: (1) buried ducts; (2) encapsulated ducts (with ccSPF); and (3) buried and encapsulated ducts. The best solution for each situation depends on the climate, age of the house, and the configuration of the HVAC system and attic. For new construction projects, the team recommends that ducts be both encapsulated and buried as the minimal planning and costs required for this will yield optimal energy savings. The encapsulated/buried duct strategy, which utilizes ccSPF to address condensation concerns, is an approach that was developed specifically for humid climates.

  12. Imprinting bulk amorphous alloy at room temperature

    PubMed Central

    Kim, Song-Yi; Park, Eun-Soo; Ott, Ryan T.; Lograsso, Thomas A.; Huh, Moo-Young; Kim, Do-Hyang; Eckert, Jürgen; Lee, Min-Ha

    2015-01-01

    We present investigations on the plastic deformation behavior of a brittle bulk amorphous alloy by simple uniaxial compressive loading at room temperature. A patterning is possible by cold-plastic forming of the typically brittle Hf-based bulk amorphous alloy through controlling homogenous flow without the need for thermal energy or shaping at elevated temperatures. The experimental evidence suggests that there is an inconsistency between macroscopic plasticity and deformability of an amorphous alloy. Moreover, imprinting of specific geometrical features on Cu foil and Zr-based metallic glass is represented by using the patterned bulk amorphous alloy as a die. These results demonstrate the ability of amorphous alloys or metallic glasses to precisely replicate patterning features onto both conventional metals and the other amorphous alloys. Our work presents an avenue for avoiding the embrittlement of amorphous alloys associated with thermoplastic forming and yields new insight the forming application of bulk amorphous alloys at room temperature without using heat treatment. PMID:26563908

  13. Imprinting bulk amorphous alloy at room temperature

    SciTech Connect

    Kim, Song-Yi; Park, Eun-Soo; Ott, Ryan T.; Lograsso, Thomas A.; Huh, Moo-Young; Kim, Do-Hyang; Eckert, Jürgen; Lee, Min-Ha

    2015-11-13

    We present investigations on the plastic deformation behavior of a brittle bulk amorphous alloy by simple uniaxial compressive loading at room temperature. A patterning is possible by cold-plastic forming of the typically brittle Hf-based bulk amorphous alloy through controlling homogenous flow without the need for thermal energy or shaping at elevated temperatures. The experimental evidence suggests that there is an inconsistency between macroscopic plasticity and deformability of an amorphous alloy. Moreover, imprinting of specific geometrical features on Cu foil and Zr-based metallic glass is represented by using the patterned bulk amorphous alloy as a die. These results demonstrate the ability of amorphous alloys or metallic glasses to precisely replicate patterning features onto both conventional metals and the other amorphous alloys. In conclusion, our work presents an avenue for avoiding the embrittlement of amorphous alloys associated with thermoplastic forming and yields new insight the forming application of bulk amorphous alloys at room temperature without using heat treatment.

  14. Buried Alive in the Coronal Graveyard

    NASA Astrophysics Data System (ADS)

    Ayres, T. R.; Brown, A.; Harper, G. M.

    2002-12-01

    We have used the highly sensitive ``solar-blind'' Chandra High Resolution Camera (HRC-I) to search for 0.2--10 keV coronal X-ray emission from the key ``noncoronal'' red giants Arcturus (α Boo: K1 III) and Aldebaran (α Tauri: K5 III). Our program follows up previous detections of subcoronal (T ~ 105 K) emission lines, such as C 4 λ 1548, by HST STIS, and its predecessor GHRS. The two deep (19 ks) HRC-I pointings failed to detect either red giant, however, with 3 σ upper limits of 1x 10-4 cnts s-1 and 2x 10-4 cnts s-1 for Arcturus and Aldebaran, respectively. The corresponding 0.2--2.0 keV L X/L bol levels are a factor of a thousand lower than the Sun (itself already an inconspicuous coronal object), establishing new limits of coronal futility among late-type stars. At the same time, STIS far-ultraviolet spectra suggest the presence of a ``cool absorber'' in the red giant atmosphere capable of selectively extinguishing the subcoronal spectrum shortward of ~ 1500 Å. The cool absorber must lie beneath the extensive chromospheric (T ~ 7000 K) envelope, because the chromospheric lines lack absorption signatures from the cool layer. As a result, the hot-line structures must be doubly buried under a large column of neutral hydrogen, undoubtedly smothering any soft X-ray emission that might be present. If small-scale magnetic active regions indeed exist in the lower atmospheres of red giants like Arcturus and Aldebaran, they might in some way be responsible for initiating and sustaining the cool outflows of such stars. The source of the near surface magnetism could be analogous to that of the small-scale ephemeral bipolar regions seen ubiquitously on the Sun throughout the sunspot cycle, and thought to be of direct convective origin. [-3mm] This work was supported by Chandra grant G02-3014X and HST grant GO-09273.01--A to the University of Colorado.

  15. Buried Alive in the Coronal Graveyard

    NASA Astrophysics Data System (ADS)

    Ayres, Thomas R.; Brown, Alexander; Harper, Graham M.

    2003-11-01

    We have used the High Resolution Camera (HRC-I) of the Chandra X-Ray Observatory to search for coronal (T~106 K) emission from the archetype ``noncoronal'' red giants Arcturus (α Bootis=HD 124897, K1 III) and Aldebaran (α Tauri=HD 29139, K5 III). Our program follows up previous detections of ultraviolet coronal proxies such as C IV λ1548 (T~1×105 K) and O VI λ1031 (T~3×105 K). The deep (~19 ks) HRC-I pointings obtained a tentative 3 σ detection of Arcturus, with fX(0.2-2keV)=1.0+1.8-0.8×10-15 ergs cm-2 s-1 (95% confidence limits [CLs]), but failed to record Aldebaran, with an upper limit of <~1.5×10-15 ergs cm-2 s-1 (also at 95% CL). The corresponding LX/Lbol ratios are a factor of ten thousand less than the Sun, a low-activity coronal dwarf. At the same time, Hubble Space Telescope Imaging Spectrograph far-ultraviolet spectra suggest the presence of a ``cool absorber,'' probably near the base of the red giant chromosphere, imprinting discrete low-excitation absorptions on top of highly ionized features such as Si IV λ1393. The hot emission zones thus are at least partially buried under a large column of chromospheric material, which would severely attenuate any soft X-rays that might be emitted. The submerged hot structures presumably are magnetic because of their high temperatures and broad C IV profiles (FWHM~130 km s-1). Perhaps these structures are analogous to small-scale ephemeral bipolar regions seen ubiquitously on the Sun throughout the sunspot cycle and thought to be of direct convective origin. If small-scale magnetic fields indeed are present in the lower atmospheres of red giants such as Arcturus and Aldebaran, they might play a role in initiating the cool winds of such stars, perhaps through a mechanism similar to solar spicules.

  16. Model for amorphous aggregation processes

    NASA Astrophysics Data System (ADS)

    Stranks, Samuel D.; Ecroyd, Heath; van Sluyter, Steven; Waters, Elizabeth J.; Carver, John A.; von Smekal, Lorenz

    2009-11-01

    The amorphous aggregation of proteins is associated with many phenomena, ranging from the formation of protein wine haze to the development of cataract in the eye lens and the precipitation of recombinant proteins during their expression and purification. While much literature exists describing models for linear protein aggregation, such as amyloid fibril formation, there are few reports of models which address amorphous aggregation. Here, we propose a model to describe the amorphous aggregation of proteins which is also more widely applicable to other situations where a similar process occurs, such as in the formation of colloids and nanoclusters. As first applications of the model, we have tested it against experimental turbidimetry data of three proteins relevant to the wine industry and biochemistry, namely, thaumatin, a thaumatinlike protein, and α -lactalbumin. The model is very robust and describes amorphous experimental data to a high degree of accuracy. Details about the aggregation process, such as shape parameters of the aggregates and rate constants, can also be extracted.

  17. Amorphous titanium-oxide supercapacitors

    PubMed Central

    Fukuhara, Mikio; Kuroda, Tomoyuki; Hasegawa, Fumihiko

    2016-01-01

    The electric capacitance of an amorphous TiO2-x surface increases proportionally to the negative sixth power of the convex diameter d. This occurs because of the van der Waals attraction on the amorphous surface of up to 7 mF/cm2, accompanied by extreme enhanced electron trapping resulting from both the quantum-size effect and an offset effect from positive charges at oxygen-vacancy sites. Here we show that a supercapacitor, constructed with a distributed constant-equipment circuit of large resistance and small capacitance on the amorphous TiO2-x surface, illuminated a red LED for 37 ms after it was charged with 1 mA at 10 V. The fabricated device showed no dielectric breakdown up to 1,100 V. Based on this approach, further advances in the development of amorphous titanium-dioxide supercapacitors might be attained by integrating oxide ribbons with a micro-electro mechanical system. PMID:27767103

  18. Amorphous rare earth magnet powders

    SciTech Connect

    Sellers, C.H.; Branagan, D.J.; Hyde, T.A.; Lewis, L.H.; Panchanathan, V.

    1996-08-01

    Gas atomization (GA) processing does not generally have a high enough cooling rate to produce the initial amorphous microstructure needed to obtain optimal magnetic properties in RE{sub 2}Fe{sub 14}B alloys. Phase separation and an underquenched microstructure result from detrimental {alpha}-Fe precipitation, and the resulting magnetic domain structure is very coarse. Additionally, there is a dramatic dependence of the magnetic properties on the cooling rate (and therefore the particle size) and the powders can be sensitive to environmental degradation. Alloy compositions designed just for GA (as opposed to melt spinning) are necessary to produce an amorphous structure that can be crystallized to result in a fine structure with magnetic properties which are independent of particle size. The addition of titanium and carbon to the melt has been found to change the solidification process sufficiently to result in an ``overquenched`` state in which most of the powder size fractions have an amorphous component. Crystallization with a brief heat treatment produces a structure which has improved magnetic properties, in part due to the ability to use compositions with higher Fe contents without {alpha}-Fe precipitation. Results from magnetometry, magnetic force microscopy, and x-ray analyses will be used to contrast the microstructure, domain structure, and magnetic properties of this new generation of amorphous powders with their multiphase predecessors.

  19. Amorphous titanium-oxide supercapacitors

    NASA Astrophysics Data System (ADS)

    Fukuhara, Mikio; Kuroda, Tomoyuki; Hasegawa, Fumihiko

    2016-10-01

    The electric capacitance of an amorphous TiO2-x surface increases proportionally to the negative sixth power of the convex diameter d. This occurs because of the van der Waals attraction on the amorphous surface of up to 7 mF/cm2, accompanied by extreme enhanced electron trapping resulting from both the quantum-size effect and an offset effect from positive charges at oxygen-vacancy sites. Here we show that a supercapacitor, constructed with a distributed constant-equipment circuit of large resistance and small capacitance on the amorphous TiO2-x surface, illuminated a red LED for 37 ms after it was charged with 1 mA at 10 V. The fabricated device showed no dielectric breakdown up to 1,100 V. Based on this approach, further advances in the development of amorphous titanium-dioxide supercapacitors might be attained by integrating oxide ribbons with a micro-electro mechanical system.

  20. Buried object remote detection technology for law enforcement

    NASA Astrophysics Data System (ADS)

    del Grande, Nancy K.; Clark, Gregory A.; Durbin, Philip F.; Fields, David J.; Hernandez, Jose E.; Sherwood, Robert J.

    1991-08-01

    A precise airborne temperature-sensing technology to detect buried objects for use by law enforcement is developed. Demonstrations have imaged the sites of buried foundations, walls and trenches; mapped underground waterways and aquifers; and been used to locate underground military objects. The methodology is incorporated in a commercially available, high signal-to-noise, dual-band infrared scanner with real-time, 12-bit digital image processing software and display. The method creates color-coded images based on surface temperature variations of 0.2 degree(s)C. Unlike other less-sensitive methods, it maps true (corrected) temperatures by removing the (decoupled) surface emissivity mask equivalent to 1 degree(s)C or 2 degree(s)C; this mask hinders interpretation of apparent (blackbody) temperatures. Once removed, it is possible to identify surface temperature patterns from small diffusivity changes at buried object sites which heat and cool differently from their surroundings. Objects made of different materials and buried at different depths are identified by their unique spectral, spatial, thermal, temporal, emissivity and diffusivity signatures. The authors have successfully located the sites of buried (inert) simulated land mines 0.1 to 0.2 m deep; sod-covered rock pathways alongside dry ditches, deeper than 0.2 m; pavement covered burial trenches and cemetery structures as deep as 0.8 m; and aquifers more than 6 m and less than 60 m deep. The technology could be adapted for drug interdiction and pollution control. For the former, buried tunnels, underground structures built beneath typical surface structures, roof-tops disguised by jungle canopies, and covered containers used for contraband would be located. For the latter, buried waste containers, sludge migration pathways from faulty containers, and the juxtaposition of groundwater channels, if present, nearby, would be depicted. The precise airborne temperature-sensing technology has a promising potential

  1. Local flexibility facilitates oxidization of buried methionine residues.

    PubMed

    Xu, Kuiran; Uversky, Vladimir N; Xue, Bin

    2012-06-01

    In proteins, all amino acid residues are susceptible to oxidation by various reactive oxygen species (ROS), with methionine and cysteine residues being particularly sensitive to oxidation. Methionine oxidation is known to lead to destabilization and inactivation of proteins, and oxidatively modified proteins can accumulate during aging, oxidative stress, and in various age-related diseases. Although the efficiency of a given methionine oxidation can depend on its solvent accessibility (evaluated from a protein structure as the accessible surface area of the corresponding methionine residue), many experimental results on oxidation rate and oxidation sites cannot be unequivocally explained by the methionine solvent accessible surface area alone. In order to explore other possible mechanisms, we analyzed a set of seventy-one oxidized methionines contained in thirty-one proteins by various bioinformatics tools. In which, 41% of the methionines are exposed, 15% are buried but with various degree of flexibility, and the rest 44% are buried and structured. Buried but highly flexible methionines can be oxidized. Buried and less flexible methionines can acquire additional local structural flexibility from flanking regions to facilitate the oxidation. Oxidation of buried and structured methionine can also be promoted by the oxidation of neighboring methionine that is more exposed and/or flexible. Our data are consistent with the hypothesis that protein structural flexibility represents another important factor favoring the oxidation process.

  2. Experimental investigation of buried tritium in plant and animal tissues

    SciTech Connect

    Kim, S. B.; Workman, W. J. G.; Davis, P. A.

    2008-07-15

    Buried exchangeable tritium appears as part of organically bound tritium (OBT) in the traditional experimental determination of OBT. Since buried tritium quickly exchanges with hydrogen atoms in the body following ingestion, assuming that it is part of OBT rather than part of tritiated water (HTO) could result in a significant overestimate of the ingestion dose. This paper documents an experimental investigation into the existence, amount and significance of buried tritium in plant and fish samples. OBT concentrations in the samples were determined in the traditional way and also following denaturing with five chemical solutions that break down large molecules and expose buried tritium to exchange with free hydrogen atoms. A comparison of the OBT concentrations before and after denaturing, together with the concentration of HTO in the supernatant obtained after denaturing, suggests that buried OBT may exist but makes up less than 5% of the OBT concentration in plants and at most 20% of the OBT concentration in fish. The effects of rinse time and rinse water volumes were investigated to optimize the removal of exchangeable OBT from the samples. (authors)

  3. Flexible amorphous metal films with high stability

    NASA Astrophysics Data System (ADS)

    Liu, M.; Cao, C. R.; Lu, Y. M.; Wang, W. H.; Bai, H. Y.

    2017-01-01

    We report the formation of amorphous Cu50Zr50 films with a large-area of more than 100 cm2. The films were fabricated by ion beam assisted deposition with a slow deposition rate at moderate temperature. The amorphous films have markedly enhanced thermal stability, excellent flexibility, and high reflectivity with atomic level smoothness. The multifunctional properties of the amorphous films are favorites in the promising applications of smart skin or wearable devices. The method of preparing highly stable amorphous metal films by tuning the deposition rate instead of deposition temperature could pave a way for exploring amorphous metal films with unique properties.

  4. Buried waste integrated demonstration FY 94 deployment plan

    SciTech Connect

    Hyde, R.A.; Walker, S.; Garcia, M.M.

    1994-05-01

    The Buried Waste Integrated Demonstration (BWID) is a program funded by the U.S. Department of Energy Office of Technology Development. BWID supports the applied research, development, demonstration, testing, and evaluation of a suite of advanced technologies that together form a comprehensive remediation system for the effective and efficient remediation of buried waste. The fiscal year (FY) 1994 effort will fund thirty-eight technologies in five areas of buried waste site remediation: site characterization, waste characterization, retrieval, treatment, and containment/stabilization. This document is the basic operational planning document for deployment of all BWID projects. Discussed in this document are the BWID preparations for INEL field demonstrations, INEL laboratory demonstrations, non-INEL demonstrations, and paper studies. Each technology performing tests will prepare a test plan to detail the specific procedures, objectives, and tasks of each test. Therefore, information specific to testing each technology is intentionally omitted from this document.

  5. Autonomous robotic platforms for locating radio sources buried under rubble

    NASA Astrophysics Data System (ADS)

    Tasu, A. S.; Anchidin, L.; Tamas, R.; Paun, M.; Danisor, A.; Petrescu, T.

    2016-12-01

    This paper deals with the use of autonomous robotic platforms able to locate radio signal sources such as mobile phones, buried under collapsed buildings as a result of earthquakes, natural disasters, terrorism, war, etc. This technique relies on averaging position data resulting from a propagation model implemented on the platform and the data acquired by robotic platforms at the disaster site. That allows us to calculate the approximate position of radio sources buried under the rubble. Based on measurements, a radio map of the disaster site is made, very useful for locating victims and for guiding specific rubble lifting machinery, by assuming that there is a victim next to a mobile device detected by the robotic platform; by knowing the approximate position, the lifting machinery does not risk to further hurt the victims. Moreover, by knowing the positions of the victims, the reaction time is decreased, and the chances of survival for the victims buried under the rubble, are obviously increased.

  6. End effectors and attachments for buried waste excavation equipment

    SciTech Connect

    King, R.H.

    1993-09-01

    The Buried Waste Integrated Demonstration (BWID) supports the applied research, development, demonstration, and evaluation of a suite of advanced technologies that form a comprehensive remediation system for the effective and efficient remediation of buried waste. Their efforts are identified and coordinated in support of the U.S. Department of Energy (DOE), Environmental Restoration and Waste Management (ER&WM) Department`s needs and objectives. The present focus of BWID is to support retrieval and ex-situ treatment configuration options. Future activities will explore and support containment, and stabilization efforts in addition to the retrieval/ex situ treatment options. This report presents a literature search on the state-of-the-art in end effectors and attachments in support of excavator of buried transuranic waste. Included in the report are excavator platforms and a discussion of the various attachments. Also included is it list of vendors and specifications.

  7. Tabernaemontana divaricata leaves extract exacerbate burying behavior in mice

    PubMed Central

    Chanchal, Raj; Balasubramaniam, Arumugam; Navin, Raj; Nadeem, Sayyed

    2015-01-01

    Objective: Tabernaemontana divaricata (TD) from Apocynaceae family offers the traditional folklore medicinal benefits such as an anti-epileptic, anti-mania, brain tonic, and anti-oxidant. The aim of the present study was to evaluate the effect of ethanolic extract of TD leaves on burying behavior in mice. Materials and Methods: Mice were treated with oral administration (p.o.) of ethanolic extract of TD (100, 200, and 300 mg/kg). Fluoxetine (FLX, a selective serotonin reuptake inhibitor) was used as a reference drug. Obsessive-compulsive behavior was evaluated using marble-burying apparatus. Results: TD at doses of 100, 200, and 300 mg/kg dose-dependently inhibited the obsessive and compulsive behavior. The similar results were obtained from 5, 10, and 20 mg/kg of FLX. TD and FLX did not affect motor activity. Conclusion: The results indicated that TD and FLX produced similar inhibitory effects on marble-burying behavior. PMID:26445709

  8. The gravity field of topography buried by sediments

    NASA Technical Reports Server (NTRS)

    Sandwell, D. T.; Liu, C. S.

    1985-01-01

    The gravity field over topography in the northern Indian Ocean that was completely buried by sediments of the Bengal Fan was investigated to understand the effect of sedimentation on the continental gravity field. An isopach map made from the seismic reflection and refraction in the Bay of Bengal shows two prominent N-S trending features in the basement topography. The northernmost portion of the Ninetyeast Ridge is totally buried by sediments north of 10 deg N. The other buried ridge trends roughly N-S for 1400 km at 85 deg E to the latitude of Sri Lanka and then curves toward the west. It has basement relief up to 6 km. Two free air gravity anomaly profiles across the region show a strong gravity low over the 85 deg E ridge, while the Ninetyeast Ridge shows a gravity high.

  9. Prediction of buried helices in multispan alpha helical membrane proteins.

    PubMed

    Adamian, Larisa; Liang, Jie

    2006-04-01

    Analysis of a database of structures of membrane proteins shows that membrane proteins composed of 10 or more transmembrane (TM) helices often contain buried helices that are inaccessible to phospholipids. We introduce a method for identifying TM helices that are least phospholipid accessible and for prediction of fully buried TM helices in membrane proteins from sequence information alone. Our method is based on the calculation of residue lipophilicity and evolutionary conservation. Given that the number of buried helices in a membrane protein is known, our method achieves an accuracy of 78% and a Matthew's correlation coefficient of 0.68. A server for this tool (RANTS) is available online at http://gila.bioengr.uic.edu/lab/.

  10. Buried Waste Integrated Demonstration commercialization actions plans. Volume 1

    SciTech Connect

    Kaupanger, R.M.; Glore, D.

    1994-04-01

    The Buried Waste Integrated Demonstration (BWID) is sponsored by US Department of Energy (DOE) Office of Technology Development. BWID supports the development and demonstration of a suite of technologies that when integrated with commercially available baseline technologies form a comprehensive system for the effective and efficient remediation of buried waste throughout the DOE complex. BWID evaluates, validates, and demonstrates technologies and transfers this information throughout DOE and private industry to support DOE. remediation planning and implementation activities. This report documents commercialization action plans for five technologies with near-term commercialization/ implementation potential as well as provides a status of commercial and academic partners for each technology.

  11. Buried wire gage for wall shear stress measurements

    NASA Technical Reports Server (NTRS)

    Murthy, V. S.; Rose, W. C.

    1978-01-01

    A buried wire gage for measuring wall shear stress in fluid flow was studied and further developed. Several methods of making this relatively new type of gage were examined to arrive at a successful technique that is well-suited for wind-tunnel testing. A series of measurements was made to demonstrate the adequacy of a two-point calibration procedure for these gages. The buried wire gage is also demonstrated to be ideally suited for quantitative measurement of wall shear stress in wind-tunnel testing.

  12. Guided wave attenuation in coated pipes buried in sand

    NASA Astrophysics Data System (ADS)

    Leinov, Eli; Cawley, Peter; Lowe, Michael J. S.

    2016-02-01

    Long-range guided wave testing (GWT) is routinely used for the monitoring and detection of corrosion defects in above ground pipelines in various industries. The GWT test range in buried, coated pipelines is greatly reduced compared to aboveground pipelines due to energy leakage into the embedding soil. In this study, we aim to increase test ranges for buried pipelines. The effect of pipe coatings on the T(0,1) and L(0,2) guided wave attenuation is investigated using a full-scale experimental apparatus and model predictions. Tests are performed on a fusion-bonded epoxy (FBE)-coated 8" pipe, buried in loose and compacted sand over a frequency range of 10-35 kHz. The application of a low impedance coating is shown to effectively decouple the influence of the sand on the ultrasound leakage from the buried pipe. We demonstrate ultrasonic isolation of a buried pipe by coating the pipe with a Polyethylene (PE)-foam layer that has a smaller impedance than both pipe and sand and the ability to withstand the overburden load from the sand. The measured attenuation in the buried PE-foam-FBE-coated pipe is substantially reduced, in the range of 0.3-1.2 dBm-1 for loose and compacted sand conditions, compared to buried FBE-coated pipe without the PE-foam, where the measured attenuation is in the range of 1.7-4.7 dBm-1. The acoustic properties of the PE-foam are measured independently using ultrasonic interferometry technique and used in model predictions of guided wave propagation in a buried coated pipe. Good agreement is found between the attenuation measurements and model predictions. The attenuation exhibits periodic peaks in the frequency domain corresponding to the through-thickness resonance frequencies of the coating layer. The large reduction in guided wave attenuation for PE-coated pipes would lead to greatly increased GWT test ranges, so such coatings would be attractive for new pipeline installations.

  13. Novel back-reflector architecture with nanoparticle based buried light-scattering microstructures for improved solar cell performance

    NASA Astrophysics Data System (ADS)

    Desta, Derese; Ram, Sanjay K.; Rizzoli, Rita; Bellettato, Michele; Summonte, Caterina; Jeppesen, Bjarke R.; Jensen, Pia B.; Tsao, Yao-Chung; Wiggers, Hartmut; Pereira, Rui N.; Balling, Peter; Larsen, Arne Nylandsted

    2016-06-01

    A new back-reflector architecture for light-management in thin-film solar cells is proposed that includes a morphologically smooth top surface with light-scattering microstructures buried within. The microstructures are pyramid shaped, fabricated on a planar reflector using TiO2 nanoparticles and subsequently covered with a layer of Si nanoparticles to obtain a flattened top surface, thus enabling growth of good quality thin-film solar cells. The optical properties of this back-reflector show high broadband haze parameter and wide angular distribution of diffuse light-scattering. The n-i-p amorphous silicon thin-film solar cells grown on such a back-reflector show enhanced light absorption resulting in improved external quantum efficiency. The benefit of the light trapping in those solar cells is evidenced by the gains in short-circuit current density and efficiency up to 15.6% and 19.3% respectively, compared to the reference flat solar cells. This improvement in the current generation in the solar cells grown on the flat-topped (buried pyramid) back-reflector is observed even when the irradiation takes place at large oblique angles of incidence. Finite-difference-time-domain simulation results of optical absorption and ideal short-circuit current density values agree well with the experimental findings. The proposed approach uses a low cost and simple fabrication technique and allows effective light manipulation by utilizing the optical properties of micro-scale structures and nanoscale constituent particles.

  14. Growth and conduction mechanism of As-doped p-type ZnO thin films deposited by MOCVD

    SciTech Connect

    Ma, Y.; Gao, Q.; Wu, G.G.; Li, W.C.; Gao, F.B.; Yin, J.Z.; Zhang, B.L.; Du, G.T.

    2013-03-15

    Highlight: ► P-type As-doped ZnO thin films was fabricated by MOCVD after post-growth annealing. ► The formation mechanism of p-ZnO with high hole concentration above 10{sup 19} cm{sup −3} was elucidated. ► Besides As{sub Zn}–2V{sub Zn} complex, C impurities also played an important role in realizing p-ZnO. ► The formations of As{sub O} and O-C-O complex were partially contributed to the p-type ZnO: As films. - Abstract: As-doped p-type ZnO thin films were fabricated by metal organic chemical vapor deposition (MOCVD) after in situ annealing in a vacuum. The p-type conduction mechanism was suggested by the analysis of X-ray photoelectron spectroscopy and ultraviolet photoemission spectroscopy. It was found that most of the As dopants in p-ZnO thin films formed As{sub Zn}–2V{sub Zn} shallow acceptor complex, simultaneously, carbon impurities also played an important role in realizing p-type conductivity in ZnO. Substitutional carbon on oxygen site created passivated defect bands by combining with Ga atoms due to the donor-acceptor pair Coulomb binding, which shifted the valence-band maximum upwards for ZnO and thus increased the hole concentration.

  15. Investigating buried polymer interfaces using sum frequency generation vibrational spectroscopy

    PubMed Central

    Chen, Zhan

    2010-01-01

    This paper reviews recent progress in the studies of buried polymer interfaces using sum frequency generation (SFG) vibrational spectroscopy. Both buried solid/liquid and solid/solid interfaces involving polymeric materials are discussed. SFG studies of polymer/water interfaces show that different polymers exhibit varied surface restructuring behavior in water, indicating the importance of probing polymer/water interfaces in situ. SFG has also been applied to the investigation of interfaces between polymers and other liquids. It has been found that molecular interactions at such polymer/liquid interfaces dictate interfacial polymer structures. The molecular structures of silane molecules, which are widely used as adhesion promoters, have been investigated using SFG at buried polymer/silane and polymer/polymer interfaces, providing molecular-level understanding of polymer adhesion promotion. The molecular structures of polymer/solid interfaces have been examined using SFG with several different experimental geometries. These results have provided molecular-level information about polymer friction, adhesion, interfacial chemical reactions, interfacial electronic properties, and the structure of layer-by-layer deposited polymers. Such research has demonstrated that SFG is a powerful tool to probe buried interfaces involving polymeric materials, which are difficult to study by conventional surface sensitive analytical techniques. PMID:21113334

  16. System design for buried high-pressure/high-temperature pipelines

    SciTech Connect

    1998-06-01

    A pipeline expands or contracts when temperatures or pressures vary from the conditions at the time the pipeline was installed. Buried pipelines operating at high temperatures and pressures experience extreme compressive loads. Because radial expansion is limited by soil restraint, buried pipelines expand axially. High axial forces combined with imperfections in the seabed may overstress the pipeline or result in upheaval buckling. Methods to control expansion and upheaval buckling were investigated for the design of a buried high-pressure/high temperature (HP/HT) sour-gas flowline in Mobile Bay, Alabama. After investigating conventional and unconventional methods, the decision was made to use expansion loops over the length of the pipeline to protect the risers and reduce axial force in the middle of the pipeline. Expansion loops and doglegs act as springs to absorb pipeline expansion. Methods were investigated to prevent soil from accumulating around the buried expansion loops. Commercially available concrete dog houses used to protect pipelines and expansion loops from dropped objects were not suitable for burial, and fabrication of custom concrete housing was expensive. Fabrication of a steel enclosure was the solution chosen. A mathematical model based on internal-design guidelines and ultimate soil friction was used to determine placement and size of the expansion loops.

  17. 49 CFR 195.248 - Cover over buried pipeline.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... exempted in this subpart, all pipe must be buried so that it is below the level of cultivation. Except as... the pipe and the ground level, road bed, river bottom, or underwater natural bottom (as determined by... residential areas 36 (914) 30 (762) Crossing of inland bodies of water with a width of at least 100 feet...

  18. 49 CFR 195.248 - Cover over buried pipeline.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... exempted in this subpart, all pipe must be buried so that it is below the level of cultivation. Except as... the pipe and the ground level, road bed, river bottom, or underwater natural bottom (as determined by... residential areas 36 (914) 30 (762) Crossing of inland bodies of water with a width of at least 100 feet...

  19. 49 CFR 195.248 - Cover over buried pipeline.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... exempted in this subpart, all pipe must be buried so that it is below the level of cultivation. Except as... the pipe and the ground level, road bed, river bottom, or underwater natural bottom (as determined by... residential areas 36 (914) 30 (762) Crossing of inland bodies of water with a width of at least 100 feet...

  20. 49 CFR 195.248 - Cover over buried pipeline.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... exempted in this subpart, all pipe must be buried so that it is below the level of cultivation. Except as... the pipe and the ground level, road bed, river bottom, or underwater natural bottom (as determined by... residential areas 36 (914) 30 (762) Crossing of inland bodies of water with a width of at least 100 feet...

  1. 49 CFR 195.248 - Cover over buried pipeline.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... exempted in this subpart, all pipe must be buried so that it is below the level of cultivation. Except as... the pipe and the ground level, road bed, river bottom, or underwater natural bottom (as determined by... residential areas 36 (914) 30 (762) Crossing of inland bodies of water with a width of at least 100 feet...

  2. Modeling Blast Loading on Buried Reinforced Concrete Structures with Zapotec

    DOE PAGES

    Bessette, Greg C.

    2008-01-01

    A coupled Euler-Lagrange solution approach is used to model the response of a buried reinforced concrete structure subjected to a close-in detonation of a high explosive charge. The coupling algorithm is discussed along with a set of benchmark calculations involving detonations in clay and sand.

  3. Melter development needs assessment for RWMC buried wastes

    SciTech Connect

    Donaldson, A.D.; Carpenedo, R.J.; Anderson, G.L.

    1992-02-01

    This report presents a survey and initial assessment of the existing state-of-the-art melter technology necessary to thermally treat (stabilize) buried TRU waste, by producing a highly leach resistant glass/ceramic waste form suitable for final disposal. Buried mixed transuranic (TRU) waste at the Idaho National Engineering Laboratory (INEL) represents an environmental hazard requiring remediation. The Environmental Protection Agency (EPA) placed the INEL on the National Priorities List in 1989. Remediation of the buried TRU-contaminated waste via the CERCLA decision process is required to remove INEL from the National Priorities List. A Waste Technology Development (WTD) Preliminary Systems Design and Thermal Technologies Screening Study identified joule-heated and plasma-heated melters as the most probable thermal systems technologies capable of melting the INEL soil and waste to produce the desired final waste form (Iron-Enriched Basalt (IEB) glass/ceramic). The work reported herein then surveys the state of existing melter technology and assesses it within the context of processing INEL buried TRU wastes and contaminated soils. Necessary technology development work is recommended.

  4. Melter development needs assessment for RWMC buried wastes

    SciTech Connect

    Donaldson, A.D.; Carpenedo, R.J.; Anderson, G.L.

    1992-02-01

    This report presents a survey and initial assessment of the existing state-of-the-art melter technology necessary to thermally treat (stabilize) buried TRU waste, by producing a highly leach resistant glass/ceramic waste form suitable for final disposal. Buried mixed transuranic (TRU) waste at the Idaho National Engineering Laboratory (INEL) represents an environmental hazard requiring remediation. The Environmental Protection Agency (EPA) placed the INEL on the National Priorities List in 1989. Remediation of the buried TRU-contaminated waste via the CERCLA decision process is required to remove INEL from the National Priorities List. A Waste Technology Development (WTD) Preliminary Systems Design and Thermal Technologies Screening Study identified joule-heated and plasma-heated melters as the most probable thermal systems technologies capable of melting the INEL soil and waste to produce the desired final waste form [Iron-Enriched Basalt (IEB) glass/ceramic]. The work reported herein then surveys the state of existing melter technology and assesses it within the context of processing INEL buried TRU wastes and contaminated soils. Necessary technology development work is recommended.

  5. Modeling the electromagnetic detection of buried cylindrical conductors

    SciTech Connect

    Moses, R.W.; Kelly, R.E.; Mack, J.M.

    1996-05-01

    The remote detection of buried structures and tunnels is important to the mining, construction, and defense industries. It is often desirable to identify underground power lines, pipe lines, and utility tunnels which have unique electromagnetic cross sections. A computational model for the electromagnetic detection of buried conducting cylinders is described in this paper. The source of electromagnetic radiation is either current injection into the soil or a surface based magnetic dipole with possible extensions to airborne platforms. Frequency ranges from a few kHz to 100 kHz are considered. The target conductor is a cylinder buried directly in the soil or placed inside an insulating pipe. The receiver is a magnetic gradiometer held 1m above the ground, separate from the transmitter. Data are taken widely over the terrain under investigation. Cases where the target conductor is grounded at both ends, one end, or not at all are modeled. The scattered field and field gradient are computed at or above ground level and compared in magnitude and phase with the transmitted signal. Calculated results are compared with experimental tests done to detect a buried wire at Sandia National Laboratory and a tunnel at Yucca Mountain. Essential factors affecting detection performance are frequency optimization, dynamic range of reception and proper data processing.

  6. Model Development to Support Analysis of Acoustic Buried Target Data

    DTIC Science & Technology

    2007-09-30

    matrix scattering solution for a buried elongated scatterer is in progress. The spheroidal-basis T - matrix code was also exercised to compare its...superspheroid, its shape approaches that of a flat-endcapped cylinder. However, even with the use of spheroidal basis functions, stability of the T - matrix code is

  7. Buried mine detection using ground-penetrating impulse radar

    SciTech Connect

    Sargis, P.D.

    1995-03-01

    LLNL is developing a side-looking, ground-penetrating impulse radar system that can eventually be mounted on a robotic vehicle or an airborne platform to locate buried land mines. The system is described and results from field experiments are presented.

  8. Detection of concealed and buried chemicals by using multifrequency excitations

    SciTech Connect

    Gao Yaohui; Chen, Meng-Ku; Yang, Chia-En; Chang, Yun-Ching; Yao, Jim; Cheng Jiping; Yin, Stuart; Hui Rongqing; Ruffin, Paul; Brantley, Christina; Edwards, Eugene; Luo, Claire

    2010-08-15

    In this paper, we present a new type of concealed and buried chemical detection system by stimulating and enhancing spectroscopic signatures with multifrequency excitations, which includes a low frequency gradient dc electric field, a high frequency microwave field, and higher frequency infrared (IR) radiations. Each excitation frequency plays a unique role. The microwave, which can penetrate into the underground and/or pass through the dielectric covers with low attenuation, could effectively transform its energy into the concealed and buried chemicals and increases its evaporation rate from the sample source. Subsequently, a gradient dc electric field, generated by a Van De Graaff generator, not only serves as a vapor accelerator for efficiently expediting the transportation process of the vapor release from the concealed and buried chemicals but also acts as a vapor concentrator for increasing the chemical concentrations in the detection area, which enables the trace level chemical detection. Finally, the stimulated and enhanced vapors on the surface are detected by the IR spectroscopic fingerprints. Our theoretical and experimental results demonstrate that more than sixfold increase in detection signal can be achieved by using this proposed technology. The proposed technology can also be used for standoff detection of concealed and buried chemicals by adding the remote IR and/or thermal spectroscopic and imaging detection systems.

  9. Narrow band gap amorphous silicon semiconductors

    DOEpatents

    Madan, A.; Mahan, A.H.

    1985-01-10

    Disclosed is a narrow band gap amorphous silicon semiconductor comprising an alloy of amorphous silicon and a band gap narrowing element selected from the group consisting of Sn, Ge, and Pb, with an electron donor dopant selected from the group consisting of P, As, Sb, Bi and N. The process for producing the narrow band gap amorphous silicon semiconductor comprises the steps of forming an alloy comprising amorphous silicon and at least one of the aforesaid band gap narrowing elements in amount sufficient to narrow the band gap of the silicon semiconductor alloy below that of amorphous silicon, and also utilizing sufficient amounts of the aforesaid electron donor dopant to maintain the amorphous silicon alloy as an n-type semiconductor.

  10. Test plan for buried waste containment system materials

    SciTech Connect

    Weidner, J.; Shaw, P.

    1997-03-01

    The objectives of the FY 1997 barrier material work at the Idaho National Engineering and Environmental Laboratory are to (1) select a waste barrier material and verify that it is compatible with the Buried Waste Containment System Process, and (2) determine if, and how, the Buried Waste Containment System emplacement process affects the material properties and performance (on proof of principle scale). This test plan describes a set of measurements and procedures used to validate a waste barrier material for the Buried Waste Containment System. A latex modified proprietary cement manufactured by CTS Cement Manufacturing Company will be tested. Emplacement properties required for the Buried Waste Containment System process are: slump between 8 and 10 in., set time between 15 and 30 minutes, compressive strength at set of 20 psi minimum, and set temperature less than 100{degrees}C. Durability properties include resistance to degradation from carbonate, sulfate, and waste-site soil leachates. A set of baseline barrier material properties will be determined to provide a data base for comparison with the barrier materials when tested in the field. The measurements include permeability, petrographic analysis to determine separation and/or segregation of mix components, and a set of mechanical properties. The measurements will be repeated on specimens from the field test material. The data will be used to determine if the Buried Waste Containment System equipment changes the material. The emplacement properties will be determined using standard laboratory procedures and instruments. Durability of the barrier material will be evaluated by determining the effect of carbonate, sulfate, and waste-site soil leachates on the compressive strength of the barrier material. The baseline properties will be determined using standard ASTM procedures. 9 refs., 1 fig., 2 tabs.

  11. Development of a teleoperated backhoe for buried waste excavation

    SciTech Connect

    Burks, B.L.; Killough, S.M.; Thompson, D.H.

    1992-01-01

    For nearly five decades the United States (US) Department of Energy (DOE) and its predecessor agencies have engaged in broad-based research and development activities as well as nuclear weapons component production. As a by-product of these activities, large quantities of waste materials have been granted. One of the most common approaches used for solid waste storage was to bury waste containers in pits and trenches. With the current emphasis on environmental restoration, DOE now plans to either retrieve much of the legacy of buried waste or stabilize the waste in place via in situ vitrification or other means. Because of the variety of materials that have been buried over the years, the hazards of retrieval are significant if performed using conventional manned operations. The potential hazards, in addition to radiation exposure, include pyrophorics, toxic chemicals, and explosives. Although manifests exist for much of the buried waste, these records are often incomplete compared to today's requirements. Because of the potential hazards and uncertainty about waste contents and container integrity, it is highly desirable to excavate these wastes using remotely operated equipment. In this paper the authors describe the development of a teleoperated military tractor called the Small Emplacement Excavator (SEE). Development of the SEE is being funded jointly by both DOE and the US Army. The DOE sponsor is the Office of Technology Development (OTD) Robotics Program. The US Army sponsor is the Program Manager for Ammunition Logistics, Picatinny Arsenal. The primary interest for DOE is in the application to remote excavation of buried waste, while the primary emphasis for the US Army is in the remote retrieval of unexploded ordnance. Technical requirements for these two tasks are very similar and, therefore, justify a joint development project. 1 ref.

  12. Development of a teleoperated backhoe for buried waste excavation

    SciTech Connect

    Burks, B.L.; Killough, S.M.; Thompson, D.H.

    1992-05-01

    For nearly five decades the United States (US) Department of Energy (DOE) and its predecessor agencies have engaged in broad-based research and development activities as well as nuclear weapons component production. As a by-product of these activities, large quantities of waste materials have been granted. One of the most common approaches used for solid waste storage was to bury waste containers in pits and trenches. With the current emphasis on environmental restoration, DOE now plans to either retrieve much of the legacy of buried waste or stabilize the waste in place via in situ vitrification or other means. Because of the variety of materials that have been buried over the years, the hazards of retrieval are significant if performed using conventional manned operations. The potential hazards, in addition to radiation exposure, include pyrophorics, toxic chemicals, and explosives. Although manifests exist for much of the buried waste, these records are often incomplete compared to today`s requirements. Because of the potential hazards and uncertainty about waste contents and container integrity, it is highly desirable to excavate these wastes using remotely operated equipment. In this paper the authors describe the development of a teleoperated military tractor called the Small Emplacement Excavator (SEE). Development of the SEE is being funded jointly by both DOE and the US Army. The DOE sponsor is the Office of Technology Development (OTD) Robotics Program. The US Army sponsor is the Program Manager for Ammunition Logistics, Picatinny Arsenal. The primary interest for DOE is in the application to remote excavation of buried waste, while the primary emphasis for the US Army is in the remote retrieval of unexploded ordnance. Technical requirements for these two tasks are very similar and, therefore, justify a joint development project. 1 ref.

  13. 75 FR 38042 - Specifications and Drawings for Construction of Direct Buried Plant

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-01

    ... Construction of Direct Buried Plant AGENCY: Rural Utilities Service, USDA. ACTION: Proposed Rule; correction... and Drawings for Construction of Direct Buried Plant (Form 515a). This document corrects the Docket...

  14. Amorphous silicon solar cell allowing infrared transmission

    DOEpatents

    Carlson, David E.

    1979-01-01

    An amorphous silicon solar cell with a layer of high index of refraction material or a series of layers having high and low indices of refraction material deposited upon a transparent substrate to reflect light of energies greater than the bandgap energy of the amorphous silicon back into the solar cell and transmit solar radiation having an energy less than the bandgap energy of the amorphous silicon.

  15. Amorphous-Amorphous Phase Separation in API/Polymer Formulations.

    PubMed

    Luebbert, Christian; Huxoll, Fabian; Sadowski, Gabriele

    2017-02-15

    The long-term stability of pharmaceutical formulations of poorly-soluble drugs in polymers determines their bioavailability and therapeutic applicability. However, these formulations do not only often tend to crystallize during storage, but also tend to undergo unwanted amorphous-amorphous phase separations (APS). Whereas the crystallization behavior of APIs in polymers has been measured and modeled during the last years, the APS phenomenon is still poorly understood. In this study, the crystallization behavior, APS, and glass-transition temperatures formulations of ibuprofen and felodipine in polymeric PLGA excipients exhibiting different ratios of lactic acid and glycolic acid monomers in the PLGA chain were investigated by means of hot-stage microscopy and DSC. APS and recrystallization was observed in ibuprofen/PLGA formulations, while only recrystallization occurred in felodipine/PLGA formulations. Based on a successful modeling of the crystallization behavior using the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT), the occurrence of APS was predicted in agreement with experimental findings.

  16. Amorphous silicon based radiation detectors

    SciTech Connect

    Perez-Mendez, V.; Cho, G.; Drewery, J.; Jing, T.; Kaplan, S.N.; Qureshi, S.; Wildermuth, D. ); Fujieda, I.; Street, R.A. )

    1991-07-01

    We describe the characteristics of thin(1 {mu}m) and thick (>30{mu}m) hydrogenated amorphous silicon p-i-n diodes which are optimized for detecting and recording the spatial distribution of charged particles, x-rays and {gamma} rays. For x-ray, {gamma} ray, and charged particle detection we can use thin p-i-n photosensitive diode arrays coupled to evaporated layers of suitable scintillators. For direct detection of charged particles with high resistance to radiation damage, we use the thick p-i-n diode arrays. 13 refs., 7 figs.

  17. Preparation of amorphous sulfide sieves

    DOEpatents

    Siadati, Mohammad H.; Alonso, Gabriel; Chianelli, Russell R.

    2006-11-07

    The present invention involves methods and compositions for synthesizing catalysts/porous materials. In some embodiments, the resulting materials are amorphous sulfide sieves that can be mass-produced for a variety of uses. In some embodiments, methods of the invention concern any suitable precursor (such as thiomolybdate salt) that is exposed to a high pressure pre-compaction, if need be. For instance, in some cases the final bulk shape (but highly porous) may be same as the original bulk shape. The compacted/uncompacted precursor is then subjected to an open-flow hot isostatic pressing, which causes the precursor to decompose and convert to a highly porous material/catalyst.

  18. Structural study of amorphous polyaniline

    NASA Astrophysics Data System (ADS)

    Laridjani, M.; Pouget, J. P.; MacDiarmid, A. G.; Epstein, A. J.

    1992-06-01

    Many materials, especially polymers, have a substantial volume fraction with no long range crystalline order. Through these regions are often termed amorphous, they frequently have a specific local order. We describe and use here a method, base on a non-energy dispersive X-ray diffraction technique, to obtain good quality interference functions and, by Fourier transform, radial distribution functions of the amorphous structure of polymers. We apply this approach to members of a family of electronic polymers of current interest : polyaniline emeraldine bases. We show that the local order exhibits significant differences in type I and type II materials, precipitated as salt and base respectively. These studies demonstrate the importance of sample preparation in evaluating the physical properties of polyaniline, and provide a structural origin for memory effects observed in the doping-dedoping processes. Beaucoup de matériaux, spécialement les polymères, ont une importante fraction de leur volume sans ordre cristallin à longue portée. Bien que ces régions soient souvent appelées amorphes, elles présentent fréquemment un ordre local caractéristique. Nous décrivons et utilisons dans ce papier une méthode, basée sur une technique de diffraction de rayons X non dispersive en énergie, pour obtenir des fonctions d'interférence de bonne qualité et, par transformée de Fourier, la fonction de distribution radiale des polymères amorphes. Nous appliquons cette technique à plusieurs éléments d'une même famille de polymères électroniques d'intérêt actuel : les polyanilines éméraldine bases. Nous montrons que l'ordre local présente d'appréciables différences dans les matériaux de type I et II, préparés respectivement sous forme de sel et de base. Cette étude démontre l'importance des conditions de préparation sur les propriétés physiques du polyaniline et donne une base structurale aux effets observés dans les processus de dopage-dédopage de

  19. 49 CFR 193.2629 - External corrosion control: buried or submerged components.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false External corrosion control: buried or submerged... corrosion control: buried or submerged components. (a) Each buried or submerged component that is subject to external corrosive attack must be protected from external corrosion by— (1) Material that has been...

  20. 49 CFR 193.2629 - External corrosion control: buried or submerged components.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false External corrosion control: buried or submerged... corrosion control: buried or submerged components. (a) Each buried or submerged component that is subject to external corrosive attack must be protected from external corrosion by— (1) Material that has been...

  1. 49 CFR 193.2629 - External corrosion control: buried or submerged components.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false External corrosion control: buried or submerged... corrosion control: buried or submerged components. (a) Each buried or submerged component that is subject to external corrosive attack must be protected from external corrosion by— (1) Material that has been...

  2. 49 CFR 193.2629 - External corrosion control: buried or submerged components.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false External corrosion control: buried or submerged... corrosion control: buried or submerged components. (a) Each buried or submerged component that is subject to external corrosive attack must be protected from external corrosion by— (1) Material that has been...

  3. 49 CFR 193.2629 - External corrosion control: buried or submerged components.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false External corrosion control: buried or submerged... corrosion control: buried or submerged components. (a) Each buried or submerged component that is subject to external corrosive attack must be protected from external corrosion by— (1) Material that has been...

  4. Is Mg-stabilized amorphous calcium carbonate a homogeneous mixture of amorphous magnesium carbonate and amorphous calcium carbonate?

    PubMed

    Yang, Sheng-Yu; Chang, Hsun-Hui; Lin, Cang-Jie; Huang, Shing-Jong; Chan, Jerry C C

    2016-10-04

    We find two types of carbonate ions in Mg stabilized amorphous calcium carbonate (Mg-ACC), whose short-range orders are identical to those of ACC and amorphous magnesium carbonate (AMC). Mg-ACC comprises a homogeneous mixture of the nano-clusters of ACC and AMC. Their relative amount varies systematically at different pH.

  5. Laser surface treatment of amorphous metals

    NASA Astrophysics Data System (ADS)

    Katakam, Shravana K.

    Amorphous materials are used as soft magnetic materials and also as surface coatings to improve the surface properties. Furthermore, the nanocrystalline materials derived from their amorphous precursors show superior soft magnetic properties than amorphous counter parts for transformer core applications. In the present work, laser based processing of amorphous materials will be presented. Conventionally, the nanocrystalline materials are synthesized by furnace heat treatment of amorphous precursors. Fe-based amorphous/nanocrystalline materials due to their low cost and superior magnetic properties are the most widely used soft magnetic materials. However, achieving nanocrystalline microstructure in Fe-Si-B ternary system becomes very difficult owing its rapid growth rate at higher temperatures and sluggish diffusion at low temperature annealing. Hence, nanocrystallization in this system is achieved by using alloying additions (Cu and Nb) in the ternary Fe-Si-B system. Thus, increasing the cost and also resulting in reduction of saturation magnetization. laser processing technique is used to achieve extremely fine nanocrystalline microstructure in Fe-Si-B amorphous precursor. Microstructure-magnetic Property-laser processing co-relationship has been established for Fe-Si-B ternary system using analytical techniques. Laser processing improved the magnetic properties with significant increase in saturation magnetization and near zero coercivity values. Amorphous materials exhibit excellent corrosion resistance by virtue of their atomic structure. Fe-based amorphous materials are economical and due to their ease of processing are of potential interest to synthesize as coatings materials for wear and corrosion resistance applications. Fe-Cr-Mo-Y-C-B amorphous system was used to develop thick coatings on 4130 Steel substrate and the corrosion resistance of the amorphous coatings was improved. It is also shown that the mode of corrosion depends on the laser processing

  6. Fluorination of amorphous thin-film materials with xenon fluoride

    DOEpatents

    Weil, R.B.

    1987-05-01

    A method is disclosed for producing fluorine-containing amorphous semiconductor material, preferably comprising amorphous silicon. The method includes depositing amorphous thin-film material onto a substrate while introducing xenon fluoride during the film deposition process.

  7. Fluorination of amorphous thin-film materials with xenon fluoride

    DOEpatents

    Weil, Raoul B.

    1988-01-01

    A method is disclosed for producing fluorine-containing amorphous semiconductor material, preferably comprising amorphous silicon. The method includes depositing amorphous thin-film material onto a substrate while introducing xenon fluoride during the film deposition process.

  8. Radar glory from buried craters on icy moons

    NASA Technical Reports Server (NTRS)

    Eshleman, Von R.

    1986-01-01

    Three ice-covered moons of Jupiter, in comparison with rocky planets and earth's moon, produce radar echoes of astounding strengths and bizarre polarizations. Scattering from buried craters can explain these and other anomalous properties of the echoes. The role of such craters is analogous to that of the water droplets that create the apparition known as 'the glory', the optically bright region surrounding an observer's shadow on a cloud. Both situations involve the electromagnetic phenomenon of total internal reflection at a dielectric interface, operating in a geometry that strongly favors exact backscattering. Dim surface craters are transformed into bright glory holes by being buried under somewhat denser material, thereby increasing the intensity of their echoes by factors of hundreds. The dielectric interface thus formed at the crater walls nicely accounts for the unusual polarizations of the echoes.

  9. Radar glory from buried craters on icy moons

    NASA Astrophysics Data System (ADS)

    Eshleman, Von R.

    1986-10-01

    Three ice-covered moons of Jupiter, in comparison with rocky planets and earth's moon, produce radar echoes of astounding strengths and bizarre polarizations. Scattering from buried craters can explain these and other anomalous properties of the echoes. The role of such craters is analogous to that of the water droplets that create the apparition known as 'the glory', the optically bright region surrounding an observer's shadow on a cloud. Both situations involve the electromagnetic phenomenon of total internal reflection at a dielectric interface, operating in a geometry that strongly favors exact backscattering. Dim surface craters are transformed into bright glory holes by being buried under somewhat denser material, thereby increasing the intensity of their echoes by factors of hundreds. The dielectric interface thus formed at the crater walls nicely accounts for the unusual polarizations of the echoes.

  10. Common causes of material degradation in buried piping

    SciTech Connect

    Jenkins, C.F.

    1997-01-20

    Buried pipe may fail for innumerable reasons. Causes can be mechanical damage/breakage, chemically initiated corrosion, or a combination. Failures may originate either internally or externally on the pipe. They may be related to flaws in the design, to excessive or unanticipated internal pressure or ground level loading, and/or to poor or uncertain installation practice. Or the pipe may simply ``wear out`` in service. Steel is strong and very forgiving in underground applications, especially with regard to backfill. However, soil support developed through densification or compaction is critical for brittle concrete and vitrified clay tile pipe, and is very important for cast iron and plastic pipe. Chemistry of the soil determines whether or not it will enhance corrosion or other types of degradation. Various causes and mechanisms for deterioration of buried pipe are indicated. Some peculiarities of the different materials of construction are characterized. Repair methods and means to circumvent special problems are described.

  11. Vertical Bipolar Charge Plasma Transistor with Buried Metal Layer

    PubMed Central

    Nadda, Kanika; Kumar, M. Jagadesh

    2015-01-01

    A self-aligned vertical Bipolar Charge Plasma Transistor (V-BCPT) with a buried metal layer between undoped silicon and buried oxide of the silicon-on-insulator substrate, is reported in this paper. Using two-dimensional device simulation, the electrical performance of the proposed device is evaluated in detail. Our simulation results demonstrate that the V-BCPT not only has very high current gain but also exhibits high BVCEO · fT product making it highly suitable for mixed signal high speed circuits. The proposed device structure is also suitable for realizing doping-less bipolar charge plasma transistor using compound semiconductors such as GaAs, SiC with low thermal budgets. The device is also immune to non-ideal current crowding effects cropping up at high current densities. PMID:25597295

  12. Imaging and controlling plasmonic interference fields at buried interfaces

    NASA Astrophysics Data System (ADS)

    Lummen, Tom T. A.; Lamb, Raymond J.; Berruto, Gabriele; Lagrange, Thomas; Dal Negro, Luca; García de Abajo, F. Javier; McGrouther, Damien; Barwick, B.; Carbone, F.

    2016-10-01

    Capturing and controlling plasmons at buried interfaces with nanometre and femtosecond resolution has yet to be achieved and is critical for next generation plasmonic devices. Here we use light to excite plasmonic interference patterns at a buried metal-dielectric interface in a nanostructured thin film. Plasmons are launched from a photoexcited array of nanocavities and their propagation is followed via photon-induced near-field electron microscopy (PINEM). The resulting movie directly captures the plasmon dynamics, allowing quantification of their group velocity at ~0.3 times the speed of light, consistent with our theoretical predictions. Furthermore, we show that the light polarization and nanocavity design can be tailored to shape transient plasmonic gratings at the nanoscale. This work, demonstrating dynamical imaging with PINEM, paves the way for the femtosecond and nanometre visualization and control of plasmonic fields in advanced heterostructures based on novel two-dimensional materials such as graphene, MoS2, and ultrathin metal films.

  13. Buried Porous Silicon-Germanium Layers in Monocrystalline Silicon Lattices

    NASA Technical Reports Server (NTRS)

    Fathauer, Robert W. (Inventor); George, Thomas (Inventor); Jones, Eric W. (Inventor)

    1998-01-01

    Monocrystalline semiconductor lattices with a buried porous semiconductor layer having different chemical composition is discussed and monocrystalline semiconductor superlattices with a buried porous semiconductor layers having different chemical composition than that of its monocrystalline semiconductor superlattice are discussed. Lattices of alternating layers of monocrystalline silicon and porous silicon-germanium have been produced. These single crystal lattices have been fabricated by epitaxial growth of Si and Si-Ge layers followed by patterning into mesa structures. The mesa structures are strain etched resulting in porosification of the Si-Ge layers with a minor amount of porosification of the monocrystalline Si layers. Thicker Si-Ge layers produced in a similar manner emitted visible light at room temperature.

  14. FY-94 buried waste integrated demonstration program report

    SciTech Connect

    Not Available

    1994-11-01

    The Buried Waste Integrated Demonstration (BWID) supports the applied research, development, demonstration, and evaluation of a multitude of advanced technologies. These technologies are being integrated to form a comprehensive remediation system for the effective and efficient remediation of buried waste. These efforts are identified and coordinated in support of the U.S. Department of Energy (DOE), Environmental Restoration and Waste Management (ER/WM) needs and objectives. This document summarizes previous demonstrations and describes the FY-94 BWID technology development and demonstration activities. Sponsored by the DOE Office of Technology Development (OTD), BWID works with universities and private industry to develop these technologies, which are being transferred to the private sector for use nationally and internationally. A public participation policy has been established to provide stakeholders with timely and accurate information and meaningful opportunities for involvement in the technology development and demonstration process.

  15. Vertical bipolar charge plasma transistor with buried metal layer.

    PubMed

    Nadda, Kanika; Kumar, M Jagadesh

    2015-01-19

    A self-aligned vertical Bipolar Charge Plasma Transistor (V-BCPT) with a buried metal layer between undoped silicon and buried oxide of the silicon-on-insulator substrate, is reported in this paper. Using two-dimensional device simulation, the electrical performance of the proposed device is evaluated in detail. Our simulation results demonstrate that the V-BCPT not only has very high current gain but also exhibits high BVCEO · f(T) product making it highly suitable for mixed signal high speed circuits. The proposed device structure is also suitable for realizing doping-less bipolar charge plasma transistor using compound semiconductors such as GaAs, SiC with low thermal budgets. The device is also immune to non-ideal current crowding effects cropping up at high current densities.

  16. Technology Solutions Case Study: Buried and Encapsulated Ducts, Jacksonville, Florida

    SciTech Connect

    2013-11-01

    Ductwork installed in unconditioned attics can significantly increase the overall heating and cooling costs of residential buildings. In fact, estimated duct thermal losses for single-family residential buildings with ductwork installed in unconditioned attics range from 10% to 45%. In a study of three single-story houses in Florida, the Building America research team Consortium for Advanced Residential Buildings (CARB) investigated the strategy of using buried and/or encapsulated ducts (BED) to reduce duct thermal losses in existing homes. The BED strategy consists of burying ducts in loose-fill insulation and/or encapsulating them in closed cell polyurethane spray foam (ccSPF) insulation; specifically for use in humid climates.

  17. Prediction of the TNT signature from buried UXO/landmines

    SciTech Connect

    Webb, S.W.; Phelan, J.M.; Finsterle, S.A.; Pruess, K.

    1998-06-01

    The detection and removal of buried unexploded ordnance (UXO) and landmines is one of the most important problems facing the world today. Numerous detection strategies are being developed, including infrared, electrical conductivity, ground-penetrating radar, and chemical sensors. Chemical sensors rely on the detection of TNT molecules, which are transported from buried UXO/landmines by advection and diffusion in the soil. As part of this effort, numerical models are being developed to predict TNT transport in soils including the effect of precipitation and evaporation. Modifications will be made to TOUGH2 for application to the TNT chemical sensing problem. Understanding the fate and transport of TNT in the soil will affect the design, performance and operation of chemical sensors by indicating preferred sensing strategies.

  18. In situ grouting of buried transuranic waste with polyacrylamide

    SciTech Connect

    Spalding, B.P.; Lee, S.Y.; Farmer, C.D.; Hyder, L.K.; Supaokit, P.

    1987-01-01

    This project is a demonstration and evaluation of the in situ hydrologic stabilization of buried transuranic waste at a humid site via grout injection. Two small trenches, containing buried transuranic waste, were filled with 34.000 L of polyacrylamide grout. Initial field results have indicated that voids within the trenches were totally filled by the grout and that the intratrench hydraulic conductivity was reduced to below field-measurable values. No evidence of grout constituents were observed in twelve perimeter groundwater monitoring wells indicating that grout was contained completely within the two trenches. Polyacrylamide grout was selected for field demonstration over the polyacrylate grout due to its superior performance in laboratory degradation studies. Also supporting the selection of polyacrylamide was the difficulty in controlling the set time of the acrylate polymerization. Based on preliminary degradation monitoring, the polyacrylamide was estimated to have a microbiological half-life of 362 years in the test soil. 15 refs., 9 figs., 12 tabs.

  19. Aeromagnetic Expression of Buried Basaltic Volcanoes Near Yucca Mountain, Nevada

    USGS Publications Warehouse

    O'Leary, D. W.; Mankinen, E.A.; Blakely, R.J.; Langenheim, V.E.; Ponce, D.A.

    2002-01-01

    A high-resolution aeromagnetic survey has defined a number of small dipolar anomalies indicating the presence of magnetic bodies buried beneath the surface of Crater Flat and the Amargosa Desert. Results of potential-field modeling indicate that isolated, small-volume, highly magnetic bodies embedded within the alluvial deposits of both areas produce the anomalies. Their physical characteristics and the fact that they tend to be aligned along major structural trends provide strong support for the hypothesis that the anomalies reflect buried basaltic volcanic centers. Other, similar anomalies are identified as possible targets for further investigation. High-resolution gravity and ground-magnetic surveys, perhaps along with drilling sources of selected anomalies and radiometric age determinations, can provide valuable constraints in estimating potential volcanic hazard to the potential nuclear waste repository at Yucca Mountain.

  20. Selective porous silicon formation in buried p + layers

    NASA Astrophysics Data System (ADS)

    Tsao, S. S.; Myers, D. R.; Guilinger, T. R.; Kelly, M. J.; Datye, A. K.

    1987-11-01

    We report a systematic microstructural study of enhanced lateral porous silicon formation in the buried p+ layers of n/p+/p- and p-/p+/p- structures. We find, surprisingly, extremely selective porous silicon formation due to the thin p+ layer in both structures, despite the absence of a p-n junction in the p-/p+/p- structure. The interface between the isolated island and the buried porous silicon layer was always located at the depth where the net p-type dopant concentration was 1-8×1015/cm3. The observed microstructure can largely be understood in terms of a recent model for porous Si formation in uniformly doped Si, proposed by Beale et al. [J. Cryst. Growth 73, 622 (1985)]. However, we also observe, for the first time, important effects unique to a nonuniform dopant concentration.

  1. Method of making amorphous metal composites

    DOEpatents

    Byrne, Martin A.; Lupinski, John H.

    1982-01-01

    The process comprises placing an amorphous metal in particulate form and a low molecular weight (e.g., 1000-5000) thermosetting polymer binder powder into a container, mixing these materials, and applying heat and pressure to convert the mixture into an amorphous metal composite.

  2. Co amorphous systems: A product development perspective.

    PubMed

    Chavan, Rahul B; Thipparaboina, Rajesh; Kumar, Dinesh; Shastri, Nalini R

    2016-12-30

    Solubility is one of the major problems associated with most of the new chemical entities that can be reasonably addressed by drug amorphization. However, being a high-energy form, it usually tends to re-crystallize, necessitating new formulation strategies to stabilize amorphous drugs. Polymeric amorphous solid dispersion (PASD) is one of the widely investigated strategies to stabilize amorphous drug, with major limitations like limited polymer solubility and hygroscopicity. Co amorphous system (CAM), a new entrant in amorphous arena is a promising alternative to PASD. CAMs are multi component single phase amorphous solid systems made up of two or more small molecules that may be a combination of drugs or drug and excipients. Excipients explored for CAM preparation include amino acids, carboxylic acids, nicotinamide and saccharine. Advantages offered by CAM include improved aqueous solubility and physical stability of amorphous drug, with a potential to improve therapeutic efficacy. This review attempts to address different aspects in the development of CAM as drug products. Criterion for co-former selection, various methods involved in CAM preparation, characterization tools, stability, scale up and regulatory requirements for the CAM product development are discussed.

  3. Electron tunnelling into amorphous germanium and silicon.

    NASA Technical Reports Server (NTRS)

    Smith, C. W.; Clark, A. H.

    1972-01-01

    Measurements of tunnel conductance versus bias, capacitance versus bias, and internal photoemission were made in the systems aluminum-oxide-amorphous germanium and aluminium-oxide-amorphous silicon. A function was extracted which expresses the deviation of these systems from the aluminium-oxide-aluminium system.

  4. Electron beam recrystallization of amorphous semiconductor materials

    NASA Technical Reports Server (NTRS)

    Evans, J. C., Jr.

    1968-01-01

    Nucleation and growth of crystalline films of silicon, germanium, and cadmium sulfide on substrates of plastic and glass were investigated. Amorphous films of germanium, silicon, and cadmium sulfide on amorphous substrates of glass and plastic were converted to the crystalline condition by electron bombardment.

  5. Imprinting bulk amorphous alloy at room temperature

    DOE PAGES

    Kim, Song-Yi; Park, Eun-Soo; Ott, Ryan T.; ...

    2015-11-13

    We present investigations on the plastic deformation behavior of a brittle bulk amorphous alloy by simple uniaxial compressive loading at room temperature. A patterning is possible by cold-plastic forming of the typically brittle Hf-based bulk amorphous alloy through controlling homogenous flow without the need for thermal energy or shaping at elevated temperatures. The experimental evidence suggests that there is an inconsistency between macroscopic plasticity and deformability of an amorphous alloy. Moreover, imprinting of specific geometrical features on Cu foil and Zr-based metallic glass is represented by using the patterned bulk amorphous alloy as a die. These results demonstrate the abilitymore » of amorphous alloys or metallic glasses to precisely replicate patterning features onto both conventional metals and the other amorphous alloys. In conclusion, our work presents an avenue for avoiding the embrittlement of amorphous alloys associated with thermoplastic forming and yields new insight the forming application of bulk amorphous alloys at room temperature without using heat treatment.« less

  6. Final Report: Imaging of Buried Nanoscale Optically Active Materials

    SciTech Connect

    Appelbaum, Ian

    2011-07-05

    This is a final report covering work done at University of Maryland to develop a Ballistic Electron Emission Luminescence (BEEL) microscope. This technique was intended to examine the carrier transport and photon emission in deeply buried optically-active layers and thereby provide a means for materials science to unmask the detailed consequences of experimentally controllable growth parameters, such as quantum dot size, statistics and orientation, and defect density and charge recombination pathways.

  7. The Thermal Regime Around Buried Submarine High-Voltage Cables

    NASA Astrophysics Data System (ADS)

    Emeana, C. J.; Dix, J.; Henstock, T.; Gernon, T.; Thompson, C.; Pilgrim, J.

    2015-12-01

    The expansion of offshore renewable energy infrastructure and the desire for "trans-continental shelf" power transmission, all require the use of submarine High Voltage (HV) cables. These cables have maximum operating surface temperatures of up to 70oC and are typically buried at depths of 1-2 m beneath the seabed, within the wide range of substrates found on the continental shelf. However, the thermal properties of near surface shelf sediments are poorly understood and this increases the uncertainty in determining the required cable current ratings, cable reliability and the potential effects on the sedimentary environments. We present temperature measurements from a 2D laboratory experiment, designed to represent a buried, submarine HV cable. We used a large (2.5 m-high) tank, filled with water-saturated ballotini and instrumented with 120 thermocouples, which measured the time-dependent 2D temperature distributions around the heat source. The experiments use a buried heat source to represent a series of realistic cable surface temperatures with the aim for identifying the thermal regimes generated within typical non-cohesive shelf sediments: coarse silt, fine sand and very coarse sand. The steady state heat flow regimes, and normalised and radial temperature distributions were assessed. Our results show that at temperatures up to 60°C above ambient, the thermal regimes are conductive for the coarse silt sediments and convective for the very coarse sand sediments even at 7°C above ambient. However, the heat flow pattern through the fine sand sediment shows a transition from conductive to convective heat flow at a temperature of approximately 20°C above ambient. These findings offer an important new understanding of the thermal regimes associated with submarine HV cables buried in different substrates and has huge impacts on cable ratings as the IEC 60287 standard only considers conductive heat flow as well as other potential near surface impacts.

  8. Investigation of guided waves propagation in pipe buried in sand

    SciTech Connect

    Leinov, Eli; Cawley, Peter; Lowe, Michael J.S.

    2014-02-18

    The inspection of pipelines by guided wave testing is a well-established method for the detection of corrosion defects in pipelines, and is currently used routinely in a variety of industries, e.g. petrochemical and energy. When the method is applied to pipes buried in soil, test ranges tend to be significantly compromised because of attenuation of the waves caused by energy radiating into the soil. Moreover, the variability of soil conditions dictates different attenuation characteristics, which in-turn results in different, unpredictable, test ranges. We investigate experimentally the propagation and attenuation characteristics of guided waves in pipes buried in fine sand using a well characterized full scale experimental apparatus. The apparatus consists of an 8 inch-diameter, 5.6-meters long steel pipe embedded over 3 meters of its length in a rectangular container filled with fine sand, and an air-bladder for the application of overburden pressure. Longitudinal and torsional guided waves are excited in the pipe and recorded using a transducer ring (Guided Ultrasonics Ltd). Acoustic properties of the sand are measured independently in-situ and used to make model predictions of wave behavior in the buried pipe. We present the methodology and the systematic measurements of the guided waves under a range of conditions, including loose and compacted sand. It is found that the application of overburden pressure modifies the compaction of the sand and increases the attenuation, and that the measurement of the acoustic properties of sand allows model prediction of the attenuation of guided waves in buried pipes with a high level of confidence.

  9. Multi-Sensor Detection of Obscured and Buried Objects

    DTIC Science & Technology

    2014-12-22

    metal content (ATLM), and simulated mines (SIM). The targets were buried up to 6 in. deep . Multiple data collections were performed at each site at...evaluating: Year 1 • Detection and discrimination of land mines in ground-penetrating radar based on edge histogram descriptors and a Possibilistic K...and its Application to Land Mine Detection, • Airborne and Ground Sensor Fusion for Target Detection, and • Variational Mixture of Experts for

  10. Compensated amorphous-silicon solar cell

    DOEpatents

    Devaud, G.

    1982-06-21

    An amorphous silicon solar cell including an electrically conductive substrate, a layer of glow discharge deposited hydrogenated amorphous silicon having regions of differing conductivity with at least one region of intrinsic hydrogenated amorphous silicon. The layer of hydrogenated amorphous silicon has opposed first and second major surfaces where the first major surface contacts the elecrically conductive substrate and an electrode for electrically contacting the second major surface. The intrinsic hydrogenated amorphous silicon region is deposited in a glow discharge with an atmosphere which includes not less than about 0.02 atom percent mono-atomic boron. An improved N.I.P. solar cell is disclosed using a BF/sub 3/ doped intrinsic layer.

  11. Neutron irradiation induced amorphization of silicon carbide

    SciTech Connect

    Snead, L.L.; Hay, J.C.

    1998-09-01

    This paper provides the first known observation of silicon carbide fully amorphized under neutron irradiation. Both high purity single crystal hcp and high purity, highly faulted (cubic) chemically vapor deposited (CVD) SiC were irradiated at approximately 60 C to a total fast neutron fluence of 2.6 {times} 10{sup 25} n/m{sup 2}. Amorphization was seen in both materials, as evidenced by TEM, electron diffraction, and x-ray diffraction techniques. Physical properties for the amorphized single crystal material are reported including large changes in density ({minus}10.8%), elastic modulus as measured using a nanoindentation technique ({minus}45%), hardness as measured by nanoindentation ({minus}45%), and standard Vickers hardness ({minus}24%). Similar property changes are observed for the critical temperature for amorphization at this neutron dose and flux, above which amorphization is not possible, is estimated to be greater than 130 C.

  12. Amorphization of sugar hydrates upon milling.

    PubMed

    Willart, J F; Dujardin, N; Dudognon, E; Danède, F; Descamps, M

    2010-07-19

    The possibility to amorphize anhydrous crystalline sugars, like lactose, trehalose and glucose, by mechanical milling was previously reported. We test here the possibility to amorphize the corresponding crystalline hydrates: lactose monohydrate, trehalose dihydrate and glucose monohydrate using fully identical milling procedures. The results show that only the first hydrate amorphizes while the other two remain structurally invariant. These different behaviours are attributed to the plasticizing effect of the structural water molecules which can decrease the glass transition temperature below the milling temperature. The results reveal clearly the fundamental role of the glass transition in the solid-state amorphization process induced by milling, and they also explain why crystalline hydrates are systematically more difficult to amorphize by milling than their anhydrous counterpart. The investigations have been performed by differential scanning calorimetry and powder X-ray diffraction.

  13. Structure, thermodynamics, and crystallization of amorphous hafnia

    SciTech Connect

    Luo, Xuhui; Demkov, Alexander A.

    2015-09-28

    We investigate theoretically amorphous hafnia using the first principles melt and quench method. We identify two types of amorphous structures of hafnia. Type I and type II are related to tetragonal and monoclinic hafnia, respectively. We find type II structure to show stronger disorder than type I. Using the phonon density of states, we calculate the specific heat capacity for type II amorphous hafnia. Using the nudged elastic band method, we show that the averaged transition barrier between the type II amorphous hafnia and monoclinic phase is approximately 0.09 eV/HfO{sub 2}. The crystallization temperature is estimated to be 421 K. The calculations suggest an explanation for the low thermal stability of amorphous hafnia.

  14. Buried-euxenic-basin model sets Tarim basin potential

    SciTech Connect

    Hsu, K.J. )

    1994-11-28

    The Tarim basin is the largest of the three large sedimentary basins of Northwest China. The North and Southwest depressions of Tarim are underlain by thick sediments and very thin crust. The maximum sediment thickness is more than 15 km. Of the several oil fields of Tarim, the three major fields were discovered during the last decade, on the north flank of the North depression and on the Central Tarim Uplift. The major targets of Tarim, according to the buried-euxenic-basin model, should be upper Paleozoic and lower Mesozoic reservoirs trapping oil and gas condensates from lower Paleozoic source beds. The paper describes the basin and gives a historical perspective of exploration activities and discoveries. It then explains how this basin can be interpreted by the buried-euxenic-basin model. The buried-euxenic-basin model postulates four stages of geologic evolution: (1) Sinian and early Paleozoic platform sedimentation on relic arcs and deep-marine sedimentation in back-arc basins in Xinjiang; (2) Late Paleozoic foreland-basin sedimentation in north Tarim; (3) Mesozoic and Paleogene continental deposition, subsidence under sedimentary load; and (4) Neogene pull-apart basin, wrench faulting and extension.

  15. Degradation of carbohydrates and lignins in buried woods

    NASA Astrophysics Data System (ADS)

    Hedges, John I.; Cowie, Gregory L.; Ertel, John R.; James Barbour, R.; Hatcher, Patrick G.

    1985-03-01

    Spruce, alder, and oak woods deposited in coastal sediments were characterized versus their modern counterparts by quantification of individual neutral sugars and lignin-derived phenols as well as by scanning electron microscopy, 13C NMR, and elemental analysis. The buried spruce wood from a 2500 yr old deposit was unaltered whereas an alder wood from the same horizon and an oak wood from an open ocean sediment were profoundly degraded. Individual sugar and lignin phenol analyses indicate that at least 90 and 98 wt% of the initial total polysaccharides in the buried alder and oak woods, respectively, have been degraded along with 15-25 wt% of the lignin. At least 75% of the degraded biopolymer has been physically lost from these samples. This evidence is supported by the SEM, 13C NMR and elemental analyses, all of which indicate selective loss of the carbohydrate moiety. The following order of stability was observed for the major biochemical constituents of both buried hardwoods: vanillyl and p- hydroxyl lignin structural units > syringyl lignin structural units > pectin > α-cellulose > hemicellulose. This sequence can be explained by selective preservation of the compound middle lamella regions of the wood cell walls. The magnitude and selectivity of the indicated diagenetic reactions are sufficient to cause major changes in the chemical compositions of wood-rich sedimentary organic mixtures and to provide a potentially large in situ nutrient source.

  16. Hygrothermal aging effects on buried molecular structures at epoxy interfaces.

    PubMed

    Myers, John N; Zhang, Chi; Lee, Kang-Wook; Williamson, Jaimal; Chen, Zhan

    2014-01-14

    Interfacial properties such as adhesion are determined by interfacial molecular structures. Adhesive interfaces in microelectronic packages that include organic polymers such as epoxy are susceptible to delamination during accelerated stress testing. Infrared-visible sum frequency generation vibrational spectroscopy (SFG) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) were used to study molecular structures at buried epoxy interfaces during hygrothermal aging to relate molecular structural changes at buried interfaces to decreases in macroscopic adhesion strength. SFG peaks associated with strongly hydrogen bonded water were detected at hydrophilic epoxy interfaces. Ordered interfacial water was also correlated to large decreases in interfacial adhesion strength that occurred as a result of hygrothermal aging, which suggests that water diffused to the interface and replaced original hydrogen bond networks. No water peaks were observed at hydrophobic epoxy interfaces, which was correlated with a much smaller decrease in adhesion strength from the same aging process. ATR-FTIR water signals observed in the epoxy bulk were mainly contributed by relatively weakly hydrogen bonded water molecules, which suggests that the bulk and interfacial water structure was different. Changes in interfacial methyl structures were observed regardless of the interfacial hydrophobicity which could be due to water acting as a plasticizer that restructured both the bulk and interfacial molecular structure. This research demonstrates that SFG studies of molecular structural changes at buried epoxy interfaces during hygrothermal aging can contribute to the understanding of moisture-induced failure mechanisms in electronic packages that contain organic adhesives.

  17. Detection of buried objects using reflected GNSS signals

    NASA Astrophysics Data System (ADS)

    Notarpietro, Riccardo; De Mattia, Salvatore; Campanella, Maurizio; Pei, Yuekun; Savi, Patrizia

    2014-12-01

    The use of reflected Global Navigation Satellite System (GNSS) signals for sensing the Earth has been growing rapidly in recent years. This technique is founded on the basic principle of detecting GNSS signals after they have been reflected off the Earth's surface and using them to determine the properties of the reflecting surface remotely. This is the so-called GNSS reflectometry (GNSS-R) technique. In this paper, a new application regarding the detection of metallic buried objects is analyzed and it is validated through several experimental campaigns. Although the penetration depth of GNSS signals into the ground is not optimal and depends on the soil moisture, GNSS signals can likely interact approximately with the first 10 cm of the ground and therefore can be reflected back by any metallic object buried on the first terrain layer. A very light and low-cost GNSS receiver prototype based on a software-defined radio approach was developed. This receiver can be used as a payload on board small drones or unmanned aerial systems to detect metallic objects (mines or other explosive devices). A signal processing tool based on an open-loop GNSS signal acquisition strategy was developed. The results of two experiments which show the possibility of using GNSS-R signals to detect buried metallic objects and to provide an estimate of their dimensions are discussed.

  18. Degradation of carbohydrates and lignins in buried woods

    USGS Publications Warehouse

    Hedges, J.I.; Cowie, G.L.; Ertel, J.R.; James, Barbour R.; Hatcher, P.G.

    1985-01-01

    Spruce, alder, and oak woods deposited in coastal sediments were characterized versus their modern counterparts by quantification of individual neutral sugars and lignin-derived phenols as well as by scanning electron microscopy, 13C NMR, and elemental analysis. The buried spruce wood from a 2500 yr old deposit was unaltered whereas an alder wood from the same horizon and an oak wood from an open ocean sediment were profoundly degraded. Individual sugar and lignin phenol analyses indicate that at least 90 and 98 wt% of the initial total polysaccharides in the buried alder and oak woods, respectively, have been degraded along with 15-25 wt% of the lignin. At least 75% of the degraded biopolymer has been physically lost from these samples. This evidence is supported by the SEM, 13C NMR and elemental analyses, all of which indicate selective loss of the carbohydrate moiety. The following order of stability was observed for the major biochemical constituents of both buried hardwoods: vanillyl and p-hydroxyl lignin structural units > syringyl lignin structural units > pectin > ??-cellulose > hemicellulose. This sequence can be explained by selective preservation of the compound middle lamella regions of the wood cell walls. The magnitude and selectivity of the indicated diagenetic reactions are sufficient to cause major changes in the chemical compositions of wood-rich sedimentary organic mixtures and to provide a potentially large in situ nutrient source. ?? 1985.

  19. Buried Waste Integrated Demonstration FY-95 Deployment Plan

    SciTech Connect

    Stacey, D.E.

    1995-03-01

    The Buried Waste Integrated Demonstration (BWID) is a program funded by the U.S. Department of Energy Office of Technology Development. BWID supports the applied research, development, demonstration, testing, and evaluation of a suite of advanced technologies that together form a comprehensive remediation system for the effective and efficient remediation of buried waste. The FY-95 effort will fund 24 technologies in five areas of buried waste site remediation: site characterization, waste characterization, retrieval, treatment, and containment/stabilization. Ten of these technologies will take part in the integrated field demonstration that will take place at the Idaho National Engineering Laboratory (INEL) facilities in the summer of 1995. This document is the basic operational planning document for deployment of all BWID projects funded in FY-95. Discussed in this document are the BWID preparations for the INEL integrated field demonstration, INEL research and development (R&D) demonstrations, non-INEL R&D demonstrations, and office research and technical review meetings. Each project will have a test plan detailing the specific procedures, objectives, and tasks of the test. Therefore, information that is specific to testing each technology is intentionally limited in this document.

  20. FY-95 technology catalog. Technology development for buried waste remediation

    SciTech Connect

    1995-10-01

    The US Department of Energy`s (DOE) Buried Waste Integrated Demonstration (BWID) program, which is now part of the Landfill Stabilization Focus Area (LSFA), supports applied research, development, demonstration, and evaluation of a multitude of advanced technologies dealing with underground radioactive and hazardous waste remediation. These innovative technologies are being developed as part of integrated comprehensive remediation systems for the effective and efficient remediation of buried waste sites throughout the DOE complex. These efforts are identified and coordinated in support of Environmental Restoration (EM-40) and Waste Management (EM-30) needs and objectives. Sponsored by the DOE Office of Technology Development (EM-50), BWID and LSFA work with universities and private industry to develop technologies that are being transferred to the private sector for use nationally and internationally. This report contains the details of the purpose, logic, and methodology used to develop and demonstrate DOE buried waste remediation technologies. It also provides a catalog of technologies and capabilities with development status for potential users. Past FY-92 through FY-94 technology testing, field trials, and demonstrations are summarized. Continuing and new FY-95 technology demonstrations also are described.

  1. Locomotion of Amorphous Surface Robots

    NASA Technical Reports Server (NTRS)

    Bradley, Arthur T. (Inventor)

    2016-01-01

    An amorphous robot includes a compartmented bladder containing fluid, a valve assembly, and an outer layer encapsulating the bladder and valve assembly. The valve assembly draws fluid from a compartment(s) and discharges the drawn fluid into a designated compartment to displace the designated compartment with respect to the surface. Another embodiment includes elements each having a variable property, an outer layer that encapsulates the elements, and a control unit. The control unit energizes a designated element to change its variable property, thereby moving the designated element. The elements may be electromagnetic spheres with a variable polarity or shape memory polymers with changing shape and/or size. Yet another embodiment includes an elongated flexible tube filled with ferrofluid, a moveable electromagnet, an actuator, and a control unit. The control unit energizes the electromagnet and moves the electromagnet via the actuator to magnetize the ferrofluid and lengthen the flexible tube.

  2. Locomotion of Amorphous Surface Robots

    NASA Technical Reports Server (NTRS)

    Bradley, Arthur T. (Inventor)

    2014-01-01

    An amorphous robot includes a compartmented bladder containing fluid, a valve assembly, and an outer layer encapsulating the bladder and valve assembly. The valve assembly draws fluid from a compartment(s) and discharges the drawn fluid into a designated compartment to displace the designated compartment with respect to the surface. Another embodiment includes elements each having a variable property, an outer layer that encapsulates the elements, and a control unit. The control unit energizes a designated element to change its variable property, thereby moving the designated element. The elements may be electromagnetic spheres with a variable polarity or shape memory polymers with changing shape and/or size. Yet another embodiment includes an elongated flexible tube filled with ferrofluid, a moveable electromagnet, an actuator, and a control unit. The control unit energizes the electromagnet and moves the electromagnet via the actuator to magnetize the ferrofluid and lengthen the flexible tube.

  3. Biologically formed amorphous calcium carbonate.

    PubMed

    Weiner, Steve; Levi-Kalisman, Yael; Raz, Sefi; Addadi, Lia

    2003-01-01

    Many organisms from a wide variety of taxa produce amorphous calcium carbonate (ACC), despite the fact that it is inherently unstable and relatively soluble in its pure state. These properties also make it difficult to detect and characterize ACC. Raman spectroscopy is a particularly useful method for investigating ACC because the sample can be examined wet, and extended X-ray absorption fine structure (EXAFS) analysis can provide detailed information on the short-range order. Other methods for characterizing ACC include infrared spectroscopy, thermogravimetric analysis and differential thermal analysis (TGA and DTA), transmission electron microscopy (TEM), and electron and X-ray diffraction. Because of the difficulties involved, we suspect that ACC is far more widely distributed than is presently known, and a comparison of EXAFS spectra shows that different biogenic ACC phases have different short-range order structures. We also suspect that ACC fulfils many different functions, including as a transient precursor phase during the formation of crystalline calcium carbonate.

  4. Crystalline to amorphous transformation in silicon

    SciTech Connect

    Cheruvu, S.M.

    1982-09-01

    In the present investigation, an attempt was made to understand the fundamental mechanism of crystalline-to-amorphous transformation in arsenic implanted silicon using high resolution electron microscopy. A comparison of the gradual disappearance of simulated lattice fringes with increasing Frenkel pair concentration with the experimental observation of sharp interfaces between crystalline and amorphous regions was carried out leading to the conclusion that when the defect concentration reaches a critical value, the crystal does relax to an amorphous state. Optical diffraction experiments using atomic models also supported this hypothesis. Both crystalline and amorphous zones were found to co-exist with sharp interfaces at the atomic level. Growth of the amorphous fraction depends on the temperature, dose rate and the mass of the implanted ion. Preliminary results of high energy electron irradiation experiments at 1.2 MeV also suggested that clustering of point defects occurs near room temperature. An observation in a high resolution image of a small amorphous zone centered at the core of a dislocation is presented as evidence that the nucleation of an amorphous phase is heterogeneous in nature involving clustering or segregation of point defects near existing defects.

  5. Laser irradiation to produce amorphous pharmaceuticals.

    PubMed

    Titapiwatanakun, Varin; Tankul, Junlathip; Basit, Abdul W; Gaisford, Simon

    2016-11-30

    Using a high-power CO2 laser to irradiate powder beds, it was possible to induce phase transformation to the amorphous state. Irradiation of a model drug, indometacin, resulted in formation of a glass. Varying the settings of the laser (power and raster speed) was shown to change the physicochemical properties of the glasses produced and all irradiated glasses were found to be more stable than a reference glass produced by melt-quenching. Irradiation of a powder blend of paracetamol and polyvinylpyrrolidone K30 was found to produce a solid amorphous dispersion. The results suggest that laser-irradiation might be a useful method for making amorphous pharmaceuticals.

  6. Method of producing hydrogenated amorphous silicon film

    DOEpatents

    Wiesmann, Harold J.

    1980-01-01

    This invention relates to hydrogenated amorphous silicon produced by thermally decomposing silane (SiH.sub.4) or other gases comprising H and Si, from a tungsten or carbon foil heated to a temperature of about 1400.degree.-1600.degree. C., in a vacuum of about 10.sup.-6 to 19.sup.-4 torr, to form a gaseous mixture of atomic hydrogen and atomic silicon, and depositing said gaseos mixture onto a substrate independent of and outside said source of thermal decomposition, to form hydrogenated amorphous silicon. The presence of an ammonia atmosphere in the vacuum chamber enhances the photoconductivity of the hydrogenated amorphous silicon film.

  7. Characterization of mechanical heterogeneity in amorphous solids

    NASA Astrophysics Data System (ADS)

    Peng, H. L.; Li, M. Z.; Sun, B. A.; Wang, W. H.

    2012-07-01

    The structural geometry and size distribution of the local atomic rearrangements induced by external stress in amorphous solids are investigated by molecular dynamics studies. We find that the size distribution exhibits a generic power-law behavior and their structural geometry shows fractal feature. This indicates that the local atomic rearrangements in amorphous solids are self-organized during deformation. A simple theoretical model based on the interaction of the heterogeneous elastic field sources is proposed which predicts the power-law scaling and characterizes the properties of the local atomic rearrangements in amorphous solids.

  8. Origin of Magnetic Properties in Amorphous Metals.

    DTIC Science & Technology

    1979-12-01

    Magnetic Properties of Fe-Ni-B Amorphous Alloys," F. E. Luborsky, J. L. Walter, and H. H. Liebermann , IEEE Trans. on Magnetics MAG-15, 909 (1979). Also GE...Report 78CRD132. 2. "Formation and Magnetic Properties of Fe-B-Si Amorphous Alloys," F. E. Luborsky, J. J. Becker, J. L. Walter, and H. H. Liebermann ...Amorphous Alloys," F. E. Luborsky and H. H. Liebermann , J. Appl. Phys., to appear. Also GE Report 79CRD177. 4. "The Effect of Temperature on Magnetic

  9. Photonic crystals, amorphous materials, and quasicrystals

    PubMed Central

    Edagawa, Keiichi

    2014-01-01

    Photonic crystals consist of artificial periodic structures of dielectrics, which have attracted much attention because of their wide range of potential applications in the field of optics. We may also fabricate artificial amorphous or quasicrystalline structures of dielectrics, i.e. photonic amorphous materials or photonic quasicrystals. So far, both theoretical and experimental studies have been conducted to reveal the characteristic features of their optical properties, as compared with those of conventional photonic crystals. In this article, we review these studies and discuss various aspects of photonic amorphous materials and photonic quasicrystals, including photonic band gap formation, light propagation properties, and characteristic photonic states. PMID:27877676

  10. Amorphous to Amorphous Form Transitions of Water Ice and Astrophysical Implications

    NASA Technical Reports Server (NTRS)

    Jenniskens, Peter; Blake, David F.; Chang, Sherwood (Technical Monitor)

    1994-01-01

    We have combined Selected Area Electron Diffraction (SAED) and cryogenic techniques in an instrumental configuration that allows observing the structure of vapor deposited ice as it evolves during warmup. The ice is deposited in-situ inside an Hitachi H-500 H transmission electron microscope at a base pressure of 1-5 x 10(exp -7) torr on a thin amorphous carbon substrate at 15K or 86K and warmed up at a rate of 1-2 K/min. We find a progression of amorphous forms and well defined amorphous to amorphous transitions. Apart from the well known low-density form of ice, we confirm the presence of a high-density form and find a third amorphous form that coexists with cubic ice. We will report too on the amorphous to crystalline transition and the implications of these results for radical diffusion and gas retention observed in laboratory analog studies of interstellar and cometary ices.

  11. Corrosion resistant amorphous metals and methods of forming corrosion resistant amorphous metals

    DOEpatents

    Farmer, Joseph C.; Wong, Frank M. G.; Haslam, Jeffery J.; Yang, Nancy; Lavernia, Enrique J.; Blue, Craig A.; Graeve, Olivia A.; Bayles, Robert; Perepezko, John H.; Kaufman, Larry; Schoenung, Julie; Ajdelsztajn, Leo

    2009-11-17

    A system for coating a surface comprises providing a source of amorphous metal, providing ceramic particles, and applying the amorphous metal and the ceramic particles to the surface by a spray. The coating comprises a composite material made of amorphous metal that contains one or more of the following elements in the specified range of composition: yttrium (.gtoreq.1 atomic %), chromium (14 to 18 atomic %), molybdenum (.gtoreq.7 atomic %), tungsten (.gtoreq.1 atomic %), boron (.ltoreq.5 atomic %), or carbon (.gtoreq.4 atomic %).

  12. Corrosion resistant amorphous metals and methods of forming corrosion resistant amorphous metals

    DOEpatents

    Farmer, Joseph C.; Wong, Frank M.G.; Haslam, Jeffery J.; Yang, Nancy; Lavernia, Enrique J.; Blue, Craig A.; Graeve, Olivia A.; Bayles, Robert; Perepezko, John H.; Kaufman, Larry; Schoenung, Julie; Ajdelsztajn, Leo

    2014-07-15

    A system for coating a surface comprises providing a source of amorphous metal, providing ceramic particles, and applying the amorphous metal and the ceramic particles to the surface by a spray. The coating comprises a composite material made of amorphous metal that contains one or more of the following elements in the specified range of composition: yttrium (.gtoreq.1 atomic %), chromium (14 to 18 atomic %), molybdenum (.gtoreq.7 atomic %), tungsten (.gtoreq.1 atomic %), boron (.ltoreq.5 atomic %), or carbon (.gtoreq.4 atomic %).

  13. Remote Excavation System technology evaluation report: Buried Waste Robotics Program

    SciTech Connect

    Not Available

    1993-09-01

    This document describes the results from the Remote Excavation System demonstration and testing conducted at the Idaho National Engineering Laboratory during June and July 1993. The purpose of the demonstration was to ascertain the feasibility of the system for skimming soil and removing various types of buried waste in a safe manner and within all regulatory requirements, and to compare the performances of manual and remote operation of a backhoe. The procedures and goals of the demonstration were previously defined in The Remote Excavation System Test Plan, which served as a guideline for evaluating the various components of the system and discussed the procedures used to conduct the tests.

  14. Elastic Phase Response of Silica Nanoparticles Buried in Soft Matter

    SciTech Connect

    Tetard, Laurene; Passian, Ali; Lynch, Rachel M; Voy, Brynn H; Shekhawat, Gajendra; Dravid, Vinayak; Thundat, Thomas George

    2008-01-01

    Tracking the uptake of nanomaterials by living cells is an important component in assessing both potential toxicity and in designing future materials for use in vivo. We show that the difference in the local elasticity at the site of silica (SiO{sub 2}) nanoparticles confined within a macrophage enables functional ultrasonic interactions. By elastically exciting the cell, a phase perturbation caused by the buried SiO{sub 2} nanoparticles was detected and used to map the subsurface populations of nanoparticles. Localization and mapping of stiff chemically synthesized silica nanoparticles within the cellular structures of a macrophage are important in basic as well as applied studies.

  15. Explosive fluid transmitted shock method for mining deeply buried coal

    DOEpatents

    Archibald, Paul B.

    1976-06-22

    A method for recovering coal from deeply buried deposits comprising drilling a hole down into a coal seam, filling the hole with water, and periodically detonating an explosive charge at the bottom of the water-filled hole. The water transmits the explosive shock wave to the face of the coal seam, thereby fracturing and dislodging the coal. The resulting suspension of loose coal in water is then pumped to the surface where the coal is recovered and the water is recycled to the mining operation.

  16. Ion-implanted planar-buried-heterostructure diode laser

    DOEpatents

    Brennan, Thomas M.; Hammons, Burrell E.; Myers, David R.; Vawter, Gregory A.

    1991-01-01

    A Planar-Buried-Heterostructure, Graded-Index, Separate-Confinement-Heterostructure semiconductor diode laser 10 includes a single quantum well or multi-quantum well active stripe 12 disposed between a p-type compositionally graded Group III-V cladding layer 14 and an n-type compositionally graded Group III-V cladding layer 16. The laser 10 includes an ion implanted n-type region 28 within the p-type cladding layer 14 and further includes an ion implanted p-type region 26 within the n-type cladding layer 16. The ion implanted regions are disposed for defining a lateral extent of the active stripe.

  17. Polarization lidar measurements of honeybees for locating buried landmines

    NASA Astrophysics Data System (ADS)

    Shaw, Joseph A.; Seldomridge, Nathan L.; Dunkle, Dustin L.; Nugent, Paul W.; Spangler, Lee H.; Churnside, James H.; Wilson, James W.; Bromenshenk, Jerry J.; Henderson, Colin B.

    2005-08-01

    A polarization-sensitive lidar was used to detect honeybees trained to locate buried landmines by smell. Lidar measurements of bee location agree reasonably well with maps of chemical plume strength and bee density determined by visual and video counts, indicating that the bees are preferentially located near the explosives and that the lidar identifies the locations of higher bee concentration. The co-polarized lidar backscatter signal is more effective than the cross-polarized signal for bee detection. Laboratory measurements show that the depolarization ratio of scattered light is near zero for bee wings and up to approximately thirty percent for bee bodies.

  18. Technology status report: In situ vitrification applied to buried wastes

    SciTech Connect

    Thompson, L.E. ); Bates, S.O. ); Hansen, J.E. )

    1992-09-01

    This document is a technical status report on In Situ Vitrification (ISV) as applied to buried waste; the report takes both technical and institutional concerns into perspective. The ISV process involves electrically melting such contaminated solid media as soil, sediment, sludge, and mill tailings. The resultant product is a high-quality glass-and-crystalline waste form that possesses high resistance to corrosion and leaching and is capable of long-term environmental exposure without significant degradation. The process also significantly reduces the volume of the treated solid media due to the removal of pore spaces in the soil.

  19. The thermal regime around buried submarine high-voltage cables

    NASA Astrophysics Data System (ADS)

    Emeana, C. J.; Hughes, T. J.; Dix, J. K.; Gernon, T. M.; Henstock, T. J.; Thompson, C. E. L.; Pilgrim, J. A.

    2016-08-01

    The expansion of offshore renewable energy infrastructure and the need for trans-continental shelf power transmission require the use of submarine high-voltage (HV) cables. These cables have maximum operating surface temperatures of up to 70 °C and are typically buried 1-2 m beneath the seabed, within the wide range of substrates found on the continental shelf. However, the heat flow pattern and potential effects on the sedimentary environments around such anomalously high heat sources in the near-surface sediments are poorly understood. We present temperature measurements from a 2-D laboratory experiment representing a buried submarine HV cable, and identify the thermal regimes generated within typical unconsolidated shelf sediments—coarse silt, fine sand and very coarse sand. We used a large (2 × 2.5 m2) tank filled with water-saturated spherical glass beads (ballotini) and instrumented with a buried heat source and 120 thermocouples to measure the time-dependent 2-D temperature distributions. The observed and corresponding Finite Element Method simulations of the steady state heat flow regimes and normalized radial temperature distributions were assessed. Our results show that the heat transfer and thus temperature fields generated from submarine HV cables buried within a range of sediments are highly variable. Coarse silts are shown to be purely conductive, producing temperature increases of >10 °C up to 40 cm from the source of 60 °C above ambient; fine sands demonstrate a transition from conductive to convective heat transfer between cf. 20 and 36 °C above ambient, with >10 °C heat increases occurring over a metre from the source of 55 °C above ambient; and very coarse sands exhibit dominantly convective heat transfer even at very low (cf. 7 °C) operating temperatures and reaching temperatures of up to 18 °C above ambient at a metre from the source at surface temperatures of only 18 °C. These findings are important for the surrounding near

  20. Buried archaeological structures detection using MIVIS hyperspectral airborne data

    NASA Astrophysics Data System (ADS)

    Merola, P.; Allegrini, A.; Guglietta, D.; Sampieri, S.

    2006-08-01

    The identification of buried archaeological structures, using remote sensing technologies (aerophotos or satellite and airborne images) is based on the analysis of surface spectral features changes that overlying underground terrain units, located on the basis of texture variations, humidity and vegetation cover. The study of these anomalies on MIVIS (Multispectral Infrared and Visible Imaging Spectrometer) hyperspectral data is the main goal of a research project that the CNR-IIA has carried on over different archaeological test sites. The major archaeological information were gathered by data analysis in the VIS and NIR spectral region and by use of the apparent thermal inertia image and their different vegetation index.

  1. Low-Frequency Electromagnetic Backscatter from Buried Tunnels

    SciTech Connect

    Casey, K; Pao, H

    2006-06-21

    This progress report is submitted under a contract between the Special Project Office of DARPA and Lawrence Livermore National Laboratory. The Project Manager at DARPA is Dr. Michael Zatman. Our purpose under this contract is to investigate interactions between electromagnetic waves and a class of buried targets located in multilayered media with rough interfaces. In this report, we investigate three preliminary problems. In each case our specific goal is to understand various aspects of the electromagnetic wave interaction mechanisms with targets in layered media. The first problem, discussed in Section 2, is that of low-frequency electromagnetic backscattering from a tunnel that is cut into a lossy dielectric half-space. In this problem, the interface between the upper (free space) region and the lower (ground) region is smooth. The tunnel is assumed to be a cylindrical free-space region of infinite extent in its axial direction and with a diameter that is small in comparison to the free-space wavelength. Because its diameter is small, the tunnel can be modeled as a buried ''wire'' described by an equivalent impedance per unit length. In Section 3 we extend the analysis to include a statistically rough interface between the air and ground regions. The interface is modeled as a random-phase screen. Such a screen reduces the coherent power in a plane wave that is transmitted through it, scattering some of the total power into an incoherent field. Our analysis of this second problem quantifies the reduction in the coherent power backscattered from the buried tunnel that is caused by the roughness of the air-ground interface. The problem of low-frequency electromagnetic backscattering from two buried tunnels, parallel to each other but at different locations in the ground, is considered in Section 4. In this analysis, we wish to determine the conditions under which the presence of more than one tunnel can be detected via backscattering. Section 5 concludes the report

  2. Approximation functions for airblast environments from buried charges

    SciTech Connect

    Reichenbach, H.; Behrens, K.; Kuhl, A.L.

    1993-11-01

    In EMI report E 1/93, ``Airblast Environments from Buried HE-Charges,`` fit functions were used for the compact description of blastwave parameters. The coefficients of these functions were approximated by means of second order polynomials versus DOB. In most cases, the agreement with the measured data was satisfactory; to reduce remaining noticeable deviations, an approximation by polygons (i.e., piecewise-linear approximation) was used instead of polynomials. The present report describes the results of the polygon approximation and compares them to previous data. We conclude that the polygon representation leads to a better agreement with the measured data.

  3. High efficiency, low cost buried contact silicon solar cells

    SciTech Connect

    Honsberg, C.B.; Wenham, S.R.; Ebong, A.

    1994-12-31

    The buried contact (BC) technology has demonstrated both an efficiency and cost advantage over conventional screen printed solar cells. New BC structures, in particular the double sided (DS) BC cell, allow further improvements in cost and efficiency. Improvements in efficiency arise through improved rear surface passivation. Experimental results from DSBC cells using various passivation methods demonstrate that a floating junction (FJ) passivates as well as passivation schemes used with high efficiency cells. 2D analysis and experimental results both show localized defects have prevented FJ passivation from achieving its potential and that optimization of the rear doping or by bifacial operation can improve performance.

  4. Amorphization of Silicon Carbide by Carbon Displacement

    SciTech Connect

    Devanathan, Ram; Gao, Fei; Weber, William J.

    2004-05-10

    We have used molecular dynamics simulations to examine the possibility of amorphizing silicon carbide (SiC) by exclusively displacing C atoms. At a defect generation corresponding to 0.2 displacements per atom, the enthalpy surpasses the level of melt-quenched SiC, the density decreases by about 15%, and the radial distribution function shows a lack of long-range order. Prior to amorphization, the surviving defects are mainly C Frenkel pairs (67%), but Si Frenkel pairs (18%) and anti-site defects (15%) are also present. The results indicate that SiC can be amorphized by C sublattice displacements. Chemical short-range disorder, arising mainly from interstitial production, plays a significant role in the amorphization.

  5. Amorphous Phases on the Surface of Mars

    NASA Technical Reports Server (NTRS)

    Rampe, E. B.; Morris, R. V.; Ruff, S. W.; Horgan, B.; Dehouck, E.; Achilles, C. N.; Ming, D. W.; Bish, D. L.; Chipera, S. J.

    2014-01-01

    Both primary (volcanic/impact glasses) and secondary (opal/silica, allophane, hisingerite, npOx, S-bearing) amorphous phases appear to be major components of martian surface materials based on orbital and in-situ measurements. A key observation is that whereas regional/global scale amorphous components include altered glass and npOx, local scale amorphous phases include hydrated silica/opal. This suggests widespread alteration at low water-to-rock ratios, perhaps due to snow/ice melt with variable pH, and localized alteration at high water-to-rock ratios. Orbital and in-situ measurements of the regional/global amorphous component on Mars suggests that it is made up of at least three phases: npOx, amorphous silicate (likely altered glass), and an amorphous S-bearing phase. Fundamental questions regarding the composition and the formation of the regional/global amorphous component(s) still remain: Do the phases form locally or have they been homogenized through aeolian activity and derived from the global dust? Is the parent glass volcanic, impact, or both? Are the phases separate or intimately mixed (e.g., as in palagonite)? When did the amorphous phases form? To address the question of source (local and/or global), we need to look for variations in the different phases within the amorphous component through continued modeling of the chemical composition of the amorphous phases in samples from Gale using CheMin and APXS data. If we find variations (e.g., a lack of or enrichment in amorphous silicate in some samples), this may imply a local source for some phases. Furthermore, the chemical composition of the weathering products may give insight into the formation mechanisms of the parent glass (e.g., impact glasses contain higher Al and lower Si [30], so we might expect allophane as a weathering product of impact glass). To address the question of whether these phases are separate or intimately mixed, we need to do laboratory studies of naturally altered samples made

  6. Ion-beam amorphization of semiconductors: A physical model based on the amorphous pocket population

    SciTech Connect

    Mok, K.R.C.; Jaraiz, M.; Martin-Bragado, I.; Rubio, J.E.; Castrillo, P.; Pinacho, R.; Barbolla, J.; Srinivasan, M.P.

    2005-08-15

    We introduce a model for damage accumulation up to amorphization, based on the ion-implant damage structures commonly known as amorphous pockets. The model is able to reproduce the silicon amorphous-crystalline transition temperature for C, Si, and Ge ion implants. Its use as an analysis tool reveals an unexpected bimodal distribution of the defect population around a characteristic size, which is larger for heavier ions. The defect population is split in both size and composition, with small, pure interstitial and vacancy clusters below the characteristic size, and amorphous pockets with a balanced mixture of interstitials and vacancies beyond that size.

  7. Tests Of Amorphous-Silicon Photovoltaic Modules

    NASA Technical Reports Server (NTRS)

    Ross, Ronald G., Jr.

    1988-01-01

    Progress in identification of strengths and weaknesses of amorphous-silicon technology detailed. Report describes achievements in testing reliability of solar-power modules made of amorphous-silicon photovoltaic cells. Based on investigation of modules made by U.S. manufacturers. Modules subjected to field tests, to accelerated-aging tests in laboratory, and to standard sequence of qualification tests developed for modules of crystalline-silicon cells.

  8. A Magnetic Sensor with Amorphous Wire

    PubMed Central

    He, Dongfeng; Shiwa, Mitsuharu

    2014-01-01

    Using a FeCoSiB amorphous wire and a coil wrapped around it, we have developed a sensitive magnetic sensor. When a 5 mm long amorphous wire with the diameter of 0.1 mm was used, the magnetic field noise spectrum of the sensor was about 30 pT/√Hz above 30 Hz. To show the sensitivity and the spatial resolution, the magnetic field of a thousand Japanese yen was scanned with the magnetic sensor. PMID:24940865

  9. Picosecond Electronic Relaxations In Amorphous Semiconductors

    NASA Astrophysics Data System (ADS)

    Tauc, Jan

    1983-11-01

    Using the pump and probe technique the relaxation processes of photogenerated carriers in amorphous tetrahedral semiconductors and chalcogenide glasses in the time domain from 0.5 Ps to 1.4 ns have been studied. The results obtained on the following phenomena are reviewed: hot carrier thermalization in amorphous silicon; trapping of carriers in undoped a-Si:H; trapping of carriers in deep traps produced by doping; geminate recombination in As2S3-xSex glasses.

  10. Amorphous Carbon-Boron Nitride Nanotube Hybrids

    NASA Technical Reports Server (NTRS)

    Kim, Jae Woo (Inventor); Siochi, Emilie J. (Inventor); Wise, Kristopher E. (Inventor); Lin, Yi (Inventor); Connell, John (Inventor)

    2016-01-01

    A method for joining or repairing boron nitride nanotubes (BNNTs). In joining BNNTs, the nanotube structure is modified with amorphous carbon deposited by controlled electron beam irradiation to form well bonded hybrid a-C/BNNT structures. In repairing BNNTs, the damaged site of the nanotube structure is modified with amorphous carbon deposited by controlled electron beam irradiation to form well bonded hybrid a-C/BNNT structures at the damage site.

  11. Thermal transport in amorphous materials: a review

    NASA Astrophysics Data System (ADS)

    Wingert, Matthew C.; Zheng, Jianlin; Kwon, Soonshin; Chen, Renkun

    2016-11-01

    Thermal transport plays a crucial role in performance and reliability of semiconductor electronic devices, where heat is mainly carried by phonons. Phonon transport in crystalline semiconductor materials, such as Si, Ge, GaAs, GaN, etc, has been extensively studied over the past two decades. In fact, study of phonon physics in crystalline semiconductor materials in both bulk and nanostructure forms has been the cornerstone of the emerging field of ‘nanoscale heat transfer’. On the contrary, thermal properties of amorphous materials have been relatively less explored. Recently, however, a growing number of studies have re-examined the thermal properties of amorphous semiconductors, such as amorphous Si. These studies, which included both computational and experimental work, have revealed that phonon transport in amorphous materials is perhaps more complicated than previously thought. For instance, depending on the type of amorphous materials, thermal transport occurs via three types of vibrations: propagons, diffusons, and locons, corresponding to the propagating, diffusion, and localized modes, respectively. The relative contribution of each of these modes dictates the thermal conductivity of the material, including its magnitude and its dependence on sample size and temperature. In this article, we will review the fundamental principles and recent development regarding thermal transport in amorphous semiconductors.

  12. Neutron irradiation induced amorphization of silicon carbide

    NASA Astrophysics Data System (ADS)

    Snead, L. L.; Hay, J. C.

    1999-07-01

    This paper provides the properties of bulk stoichiometric silicon carbide which has been amorphized under neutron irradiation. Both high purity single crystal hcp and high purity, highly faulted (cubic) chemically vapor deposited (CVD) SiC were irradiated at approximately 60°C to a total fast neutron fluence of 2.6 × 10 25 n/m 2. Amorphization was seen in both materials as evidenced by TEM, electron diffraction and X-ray diffraction techniques. Physical properties for the amorphized single crystal material are reported including large changes in density (-10.8%), elastic modulus as measured using a nanoindentation technique (-45%), hardness as measured by nanoindentation (-45%), and standard Vickers hardness (-24%). Similar property changes are observed for the amorphized CVD SiC. Using measured thermal conductivity data for the CVD SiC sample, the critical temperature for amorphization at this neutron dose and flux, above which amorphization is not possible, is estimated to be greater than ˜125°C.

  13. Wear Resistant Amorphous and Nanocomposite Steel Coatings

    SciTech Connect

    Branagan, Daniel James; Swank, William David; Haggard, Delon C; Fincke, James Russell; Sordelet, D.

    2001-10-01

    In this article, amorphous and nanocomposite thermally deposited steel coatings have been formed by using both plasma and high-velocity oxy-fuel (HVOF) spraying techniques. This was accomplished by developing a specialized iron-based composition with a low critical cooling rate (?104 K/s) for metallic glass formation, processing the alloy by inert gas atomization to form micron-sized amorphous spherical powders, and then spraying the classified powder to form coatings. A primarily amorphous structure was formed in the as-sprayed coatings, independent of coating thickness. After a heat treatment above the crystallization temperature (568°C), the structure of the coatings self-assembled (i.e., devitrified) into a multiphase nanocomposite microstructure with 75 to 125 nm grains containing a distribution of 20 nm second-phase grain-boundary precipitates. Vickers microhardness testing revealed that the amorphous coatings were very hard (10.2 to 10.7 GPa), with further increases in hardness after devitrification (11.4 to 12.8 GPa). The wear characteristics of the amorphous and nanocomposite coatings were determined using both two-body pin-on-disk and three-body rubber wheel wet-slurry sand tests. The results indicate that the amorphous and nanocomposite steel coatings are candidates for a wide variety of wear-resistant applications.

  14. Amorphous boron nitride at high pressure

    NASA Astrophysics Data System (ADS)

    Durandurdu, Murat

    2016-06-01

    The pressure-induced phase transformation in hexagonal boron nitrite and amorphous boron nitrite is studied using ab initio molecular dynamics simulations. The hexagonal-to-wurtzite phase transformation is successfully reproduced in the simulation with a transformation mechanism similar to one suggested in experiment. Amorphous boron nitrite, on the other hand, gradually transforms to a high-density amorphous phase with the application of pressure. This phase transformation is irreversible because a densified amorphous state having both sp3 and sp2 bonds is recovered upon pressure release. The high-density amorphous state mainly consists of sp3 bonds and its local structure is quite similar to recently proposed intermediate boron nitrite phases, in particular tetragonal structure (P42/mnm), rather than the known the wurtzite or cubic boron nitrite due to the existence of four membered rings and edge sharing connectivity. On the basis of this finding we propose that amorphous boron nitrite might be best candidate as a starting structure to synthesize the intermediate phase(s) at high pressure and temperature (probably below 800 °C) conditions.

  15. Beam and shell modes of buckling of buried pipes induced by compressive ground failure

    SciTech Connect

    Chiou, Y.J.; Chi, S.Y.

    1995-12-31

    The buckling of buried pipeline induced by compressive ground failure was investigated. Both the beam mode of buckling and local shell mode of buckling, and their interactions were studied. The pipeline response was analyzed numerically. The results agree qualitatively with past researches and possess satisfactory comparisons with actual case histories. The relations of critical buried depth versus ratio of pipe diameter to thickness for buried pipe with different imperfections and various soil foundations were established.

  16. Imaging and controlling plasmonic interference fields at buried interfaces

    PubMed Central

    Lummen, Tom T. A.; Lamb, Raymond J.; Berruto, Gabriele; LaGrange, Thomas; Dal Negro, Luca; García de Abajo, F. Javier; McGrouther, Damien; Barwick, B.; Carbone, F.

    2016-01-01

    Capturing and controlling plasmons at buried interfaces with nanometre and femtosecond resolution has yet to be achieved and is critical for next generation plasmonic devices. Here we use light to excite plasmonic interference patterns at a buried metal–dielectric interface in a nanostructured thin film. Plasmons are launched from a photoexcited array of nanocavities and their propagation is followed via photon-induced near-field electron microscopy (PINEM). The resulting movie directly captures the plasmon dynamics, allowing quantification of their group velocity at ∼0.3 times the speed of light, consistent with our theoretical predictions. Furthermore, we show that the light polarization and nanocavity design can be tailored to shape transient plasmonic gratings at the nanoscale. This work, demonstrating dynamical imaging with PINEM, paves the way for the femtosecond and nanometre visualization and control of plasmonic fields in advanced heterostructures based on novel two-dimensional materials such as graphene, MoS2, and ultrathin metal films. PMID:27725670

  17. Preliminary observations of arthropods associated with buried carrion on Oahu.

    PubMed

    Rysavy, Noel M; Goff, M Lee

    2015-03-01

    Several studies in Hawaii have focused on arthropod succession and decomposition patterns of surface remains, but the current research presents the first study to focus on shallow burials in this context. Three domestic pig carcasses (Sus scrofa L.) were buried at the depths of 20-40 cm in silty clay loam soil on an exposed ridge on the leeward side of the volcanically formed Koolau Mountain Range. One carcass was exhumed after 3 weeks, another after 6 weeks, and the last carcass was exhumed after 9 weeks. An inventory of arthropod taxa present on the carrion and in the surrounding soil and observations pertaining to decomposition were recorded at each exhumation. The longer the carrion was buried, the greater the diversity of arthropod species that were recovered from the remains. Biomass loss was calculated to be 49% at the 3-week interval, 56% at the 6-week interval, and 59% at the 9-week interval.

  18. Probing Molecular Organization and Electronic Dynamics at Buried Organic Interfaces

    NASA Astrophysics Data System (ADS)

    Roberts, Sean

    2015-03-01

    Organic semiconductors are a promising class of materials due to their ability to meld the charge transport capabilities of semiconductors with many of the processing advantages of plastics. In thin film organic devices, interfacial charge transfer often comprises a crucial step in device operation. As molecular materials, the density of states within organic semiconductors often reflect their intermolecular organization. Truncation of the bulk structure of an organic semiconductor at an interface with another material can lead to substantial changes in the density of states near the interface that can significantly impact rates for interfacial charge and energy transfer. Here, we will present the results of experiments that utilize electronic sum frequency generation (ESFG) to probe buried interfaces in these materials. Within the electric dipole approximation, ESFG is only sensitive to regions of a sample that experience a breakage of symmetry, which occurs naturally at material interfaces. Through modeling of signals measured for thin organic films using a transfer matrix-based formalism, signals from buried interfaces between two materials can be isolated and used to uncover the interfacial density of states.

  19. Full-scale retrieval of simulated buried transuranic waste

    SciTech Connect

    Valentich, D.J.

    1993-09-01

    This report describes the results of a field test conducted to determine the effectiveness of using conventional type construction equipment for the retrieval of buried transuranic (TRU) waste. A cold (nonhazardous and nonradioactive) test pit (1,100 yd{sup 3} volume) was constructed with boxes and drums filled with simulated waste materials, such as metal, plastic, wood, concrete, and sludge. Large objects, including truck beds, tanks, vaults, pipes, and beams, were also placed in the pit. These materials were intended to simulate the type of wastes found in TRU buried waste pits and trenches. A series of commercially available equipment items, such as excavators and tracked loaders outfitted with different end effectors, were used to remove the simulated waste. Work was performed from both the abovegrade and belowgrade positions. During the demonstration, a number of observations, measurements, and analyses were performed to determine which equipment was the most effective in removing the waste. The retrieval rates for the various excavation techniques were recorded. The inherent dust control capabilities of the excavation methods used were observed. The feasibility of teleoperating reading equipment was also addressed.

  20. Sensor System Fo4r Buried Waste Containment Sites

    DOEpatents

    Smith, Ann Marie; Gardner, Bradley M.; Kostelnik, Kevin M.; Partin, Judy K.; Lancaster, Gregory D.; Pfeifer, Mary Catherine

    2005-09-27

    A sensor system for a buried waste containment site having a bottom wall barrier and/or sidewall barriers, for containing hazardous waste. The sensor system includes one or more sensor devices disposed in one or more of the barriers for detecting a physical parameter either of the barrier itself or of the physical condition of the surrounding soils and buried waste, and for producing a signal representing the physical parameter detected. Also included is a signal processor for receiving signals produced by the sensor device and for developing information identifying the physical parameter detected, either for sounding an alarm, displaying a graphic representation of a physical parameter detected on a viewing screen and/or a hard copy printout. The sensor devices may be deployed in or adjacent the barriers at the same time the barriers are deployed and may be adapted to detect strain or cracking in the barriers, leakage of radiation through the barriers, the presence and leaking through the barriers of volatile organic compounds, or similar physical conditions.

  1. Sensor System Fo4r Buried Waste Containment Sites

    DOEpatents

    Smith, Ann Marie; Gardner, Bradley M.; Kostelnik, Kevin M.; Partin, Judy K.; Lancaster, Gregory D.; Pfeifer, Mary Catherine

    2003-11-18

    A sensor system for a buried waste containment site having a bottom wall barrier and sidewall barriers, for containing hazardous waste. The sensor system includes one or more sensor devices disposed in one or more of the barriers for detecting a physical parameter either of the barrier itself or of the physical condition of the surrounding soils and buried waste, and for producing a signal representing the physical parameter detected. Also included is a signal processor for receiving signals produced by the sensor device and for developing information identifying the physical parameter detected, either for sounding an alarm, displaying a graphic representation of a physical parameter detected on a viewing screen and/or a hard copy printout. The sensor devices may be deployed in or adjacent the barriers at the same time the barriers are deployed and may be adapted to detect strain or cracking in the barriers, leakage of radiation through the barriers, the presence and leaking through the barriers of volatile organic compounds, or similar physical conditions.

  2. Buried Impact Basins and the Earliest History of Mars

    NASA Technical Reports Server (NTRS)

    Frey, H. V.

    2003-01-01

    The "Quasi-Circular Depressions" (QCDs) seen in MOLA data which have little or no visible appearance in image data have been interpreted as buried impact basins on Mars. These have important implications for the age of the lowland crust, what mechanisms could produce the crustal dichotomy, and the existence of crust older than the oldest observed surface units on Mars. A global survey of large QCDs using high resolution MOLA data now available has provided further details of the earliest history of Mars. The lowlands are of Early Noachian age, slightly younger than the buried highlands and definitely older than the exposed highland surface. A depopulation of large visible basins at diameters 800 to 1300 km suggests some global scale event early in martian history, maybe related to the formation of the lowlands and/or the development of Tharsis. A suggested early disappearance of the global magnetic field can be placed within a temporal sequence of formation of the very largest impact basins.

  3. Sub-critical insonification of buried elastic shells

    NASA Astrophysics Data System (ADS)

    Veljkovic, Irena; Schmidt, Henrik

    2002-11-01

    In a shallow water environment a high frequency high grazing angle mine-hunting sonar approach is vastly limited by the coverage rate, making the detection and classification of buried objects using subcritical grazing incidence an attractive alternative. One of the central issues in mine countermeasurements regarding the physics of scattering from spherical shells is the isolation and the analysis of the resonant excitations of the system distinguishing the manmade elastic targets from rocks or other clutter. Burial of an elastic target in the seabed results in a variety of modifications to the scattered response caused by different physical mechanisms, geometric constrains, and intrinsic sediment properties. The aim of this research is to identify, analyze, and explain the fundamental effects of the sediment and the proximity of the seabed interface on the scattering of sound from elastic spherical shells insonified using low frequencies at subcritical incident angles. A new, comprehensive understanding of the goats98 experimental data was obtained distinguishing the effects of the acoustics environment from the resonant signature of a buried elastic target. To achieve this and to further investigate the more intricate details of the scattering process, a numerically improved, OASES-3D modeling framework was used. [Work supported by ONR.

  4. Analyses of SRS waste glass buried in granite in Sweden and salt in the United States

    SciTech Connect

    Williams, J.P.; Wicks, G.G.; Clark, D.E.; Lodding, A.R.

    1991-12-31

    Simulated Savannah River Site (SRS) waste glass forms have been buried in the granite geology of the Stirpa mine in Sweden for two years. Analyses of glass surfaces provided a measure of the performance of the waste glasses as a function of time. Similar SRS waste glass compositions have also been buried in salt at the WIPP facility in Carlsbad, New Mexico for a similar time period. Analyses of the SRS waste glasses buried in-situ in granite will be presented and compared to the performance of these same compositions buried in salt at WIPP.

  5. Analyses of SRS waste glass buried in granite in Sweden and salt in the United States

    SciTech Connect

    Williams, J.P. ); Wicks, G.G. ); Clark, D.E. ); Lodding, A.R. )

    1991-01-01

    Simulated Savannah River Site (SRS) waste glass forms have been buried in the granite geology of the Stirpa mine in Sweden for two years. Analyses of glass surfaces provided a measure of the performance of the waste glasses as a function of time. Similar SRS waste glass compositions have also been buried in salt at the WIPP facility in Carlsbad, New Mexico for a similar time period. Analyses of the SRS waste glasses buried in-situ in granite will be presented and compared to the performance of these same compositions buried in salt at WIPP.

  6. Stabilization of ancient organic matter in deep buried paleosols

    NASA Astrophysics Data System (ADS)

    Marin-Spiotta, E.; Chaopricha, N. T.; Mueller, C.; Diefendorf, A. F.; Plante, A. F.; Grandy, S.; Mason, J. A.

    2012-12-01

    Buried soils representing ancient surface horizons can contain large organic carbon reservoirs that may interact with the atmosphere if exposed by erosion, road construction, or strip mining. Paleosols in long-term depositional sites provide a unique opportunity for studying the importance of different mechanisms on the persistence of organic matter (OM) over millennial time-scales. We report on the chemistry and bioavailability of OM stored in the Brady soil, a deeply buried (7 m) paleosol in loess deposits of southwestern Nebraska, USA. The Brady Soil developed 9,000-13,500 years ago during a time of warming and drying. The Brady soil represents a dark brown horizon enriched in C relative to loess immediately above and below. Spanning much of the central Great Plains, this buried soil contains large C stocks due to the thickness of its A horizon (0.5 to 1 m) and wide geographic extent. Our research provides a unique perspective on long-term OM stabilization in deep soils using multiple analytical approaches. Soils were collected from the Brady soil A horizon (at 7 m depth) and modern surface A horizons (0-15 cm) at two sites for comparison. Soils were separated by density fractionation using 1.85 g ml-1 sodium polytungstate into: free particulate organic matter (fPOM) and aggregate-occluded (oPOM) of two size classes (large: >20 μm, and small: < 20 μm). The remaining dense fraction was separated into sand, silt, and clay size fractions. The distribution and age of C among density and particle-size fractions differed between surface and Brady soils. We isolated the source of the characteristic dark coloring of the Brady soil to the oPOM-small fraction, which also contained 20% of the total organic C pool in the Brady soil. The oPOM-small fraction and the bulk soil in the middle of the Brady A horizon had 14C ages of 10,500-12,400 cal yr BP, within the time that the soil was actively forming at the land surface. Surface soils showed modern ages. Lipid analyses of

  7. Electrons and phonons in amorphous semiconductors

    NASA Astrophysics Data System (ADS)

    Prasai, Kiran; Biswas, Parthapratim; Drabold, D. A.

    2016-07-01

    The coupling between lattice vibrations and electrons is one of the central concepts of condensed matter physics. The subject has been deeply studied for crystalline materials, but far less so for amorphous and glassy materials, which are among the most important for applications. In this paper, we explore the electron-lattice coupling using current tools of a first-principles computer simulation. We choose three materials to illustrate the phenomena: amorphous silicon (a-Si), amorphous selenium (a-Se) and amorphous gallium nitride (a-GaN). In each case, we show that there is a strong correlation between the localization of electron states and the magnitude of thermally induced fluctuations in energy eigenvalues obtained from the density-functional theory (i.e. Kohn-Sham eigenvalues). We provide a heuristic theory to explain these observations. The case of a-GaN, a topologically disordered partly ionic insulator, is distinctive compared to the covalent amorphous examples. Next, we explore the consequences of changing the charge state of a system as a proxy for tracking photo-induced structural changes in the materials. Where transport is concerned, we lend insight into the Meyer-Neldel compensation rule and discuss a thermally averaged Kubo-Greenwood formula as a means to estimate electrical conductivity and especially its temperature dependence. We close by showing how the optical gap of an amorphous semiconductor can be computationally engineered with the judicious use of Hellmann-Feynman forces (associated with a few defect states) using molecular dynamics simulations. These forces can be used to close or open an optical gap, and identify a structure with a prescribed gap. We use the approach with plane-wave density functional methods to identify a low-energy amorphous phase of silicon including several coordination defects, yet with a gap close to that of good quality a-Si models.

  8. Iron-based amorphous alloys and methods of synthesizing iron-based amorphous alloys

    DOEpatents

    Saw, Cheng Kiong; Bauer, William A.; Choi, Jor-Shan; Day, Dan; Farmer, Joseph C.

    2016-05-03

    A method according to one embodiment includes combining an amorphous iron-based alloy and at least one metal selected from a group consisting of molybdenum, chromium, tungsten, boron, gadolinium, nickel phosphorous, yttrium, and alloys thereof to form a mixture, wherein the at least one metal is present in the mixture from about 5 atomic percent (at %) to about 55 at %; and ball milling the mixture at least until an amorphous alloy of the iron-based alloy and the at least one metal is formed. Several amorphous iron-based metal alloys are also presented, including corrosion-resistant amorphous iron-based metal alloys and radiation-shielding amorphous iron-based metal alloys.

  9. How Burying Biomass Can Contribute to CO2 Stabilization

    NASA Astrophysics Data System (ADS)

    Cook, B.; Zeng, N.; Zaitchik, B.; Gregg, J.

    2008-12-01

    To mitigate global climate change, a portfolio of strategies will be needed to keep the atmospheric CO2 concentration below a dangerous level. Here a carbon sequestration strategy is proposed in which certain dead or live trees are harvested via collection or selective cutting, then buried in trenches or stowed away in above-ground shelters. The largely anaerobic condition under a sufficiently thick layer of soil will prevent the decomposition of the buried wood. Because a large flux of CO2 is constantly being assimilated into the world's forests via photosynthesis, cutting off its return pathway to the atmosphere forms an effective carbon sink. It is estimated that a sustainable long-term carbon sequestration potential for wood burial is 10 ± 5 GtC y-1, and currently about 65 GtC is on the world's forest floors in the form of coarse woody debris suitable for burial. The potential is largest in tropical forests (4.2 GtC y-1), followed by temperate (3.7 GtC y-1) and boreal forests (2.1 GtC y-1). Burying wood has other benefits including minimizing CO2 source from deforestation, extending the lifetime of reforestation carbon sink, and reducing fire danger. There are possible environmental impacts such as nutrient lock-up which nevertheless appears manageable, but other environmental concerns and factors will likely set a limit so that only part of the full potential can be realized. Based on data from North American logging industry, the cost for wood burial is estimated to be 14/tCO2 (50/tC), lower than the typical cost for power plant CO2 capture with geological storage. The low cost for carbon sequestration with wood burial is possible because the technique uses the natural process of photosynthesis to remove carbon from the atmosphere. The technique is low tech, distributed, safe, and can be stopped at any time, thus an attractive option for large-scale implementation in a world-wide carbon market.

  10. Detecting buried remains in Florida using ground-penetrating radar

    NASA Astrophysics Data System (ADS)

    Schultz, John Joseph

    This research tested the applicability of using ground-penetrating radar (GPR) in Florida to detect buried bodies; and assessed the effect of body size, depth, antenna type, time, and soil type on grave detection. Furthermore, because of the emphasis on decomposition, it was possible to address the role of depth, body size, time, and soil type on decomposition. The site was located in an open pasture, where 20 pig (Sus scrofa) cadavers of two average weights (29.7 and 63.8 kg) were buried at two depths (50 to 60 or 100 to 110 cm). The cadavers were monitored monthly for durations up to 21 months with GPR using 900- and 500-MHz antennae. Two different soil types were used: one composed solely of sand horizons and one composed of sand with clay horizons at approximately 1.00 m. The graves were excavated at the termination of each monitoring period to collect soil samples and score decomposition. Overall, depth was the most significant factor controlling decomposition, followed by time. Body size and soil type were not major factors. Ground-penetrating radar can be a very effective tool for grave detection in Florida. Salient anomalies were produced for the duration of this study due to a strong enough contrast between the skeleton, or decomposing body, and the surrounding soil with that of the undisturbed soil. While cadaver size and time were not major factors in grave detection, soil type and antenna choice were. Although it was possible to detect a decomposing body and a skeleton in both shallow and deep sand graves, it was difficult to image large pig cadavers retaining extensive soft tissue buried in proximity to the clay horizon in as little as six months. The clay masked the contrast of the cadavers by reducing their relative dielectric permittivity. Pig cadaver size was not a major factor in grave detection. The imagery of the 500-MHz antenna was preferred over the higher resolution of the 900-MHz, because the increased detail may result in difficulty

  11. Consecutively Preparing D-Xylose, Organosolv Lignin, and Amorphous Ultrafine Silica from Rice Husk

    PubMed Central

    Zhang, Hongxi; Ding, Xuefeng; Wang, Zichen; Zhao, Xu

    2014-01-01

    Rice husk is an abundant agricultural by-product reaching the output of 80 million tons annually in the world. The most common treatment method of rice husk is burning or burying, which caused serious air pollution and resource waste. In order to solve this problem, a new method is proposed to comprehensively utilize the rice husk in this paper. Firstly, the D-xylose was prepared from the semicellulose via dilute acid hydrolysis. Secondly, the lignin was separated via organic solvent pulping from the residue. Finally, the amorphous ultrafine silica was prepared via pyrolysis of the residue produced in the second process. In this way, the three main contents of rice husk (semicellulose, lignin, and silica) are consecutively converted to three fine chemicals, without solid waste produced. The yields of D-xylose and organosolv lignin reach 58.2% and 58.5%, respectively. The purity and specific surface of amorphous ultrafine silica reach 99.92% and 225.20 m2/g. PMID:25140120

  12. Large-Diameter Visible and Buried Impact Basins on Mars: Implications for age of the Highlands and (Buried) Lowlands and Turn-off of the Global Magnetic Field

    NASA Technical Reports Server (NTRS)

    Frey, Herbert V.

    2003-01-01

    The global populations of visible and buried impact basins less than 200 km diameter revealed by high resolution gridded MOLA indicate: (a) a small (approx. 10) number of very large basins (D=1300-3000km), most of which have remained visible over martian history; (b) a much larger population of smaller basins (D=200-800 km) with many more buried than visible (on images); (c) a depletion of visible basins at intermediate diameters which may be a signature of some global-scale event (formation of the lowlands? origin of Tharsis?); and (d) a crater retention age for the buried lowlands greater than that of the visible highlands but less than that of the total (visible + buried) highlands. Crustal magnetic anomalies are generally not present in the interiors of the largest basins with two exceptions: these two (which appear to be the oldest) may predate the demise of the global magnetic field.

  13. Large-Diameter Visible and Buried Impact Basins on Mars: Implications for Age of the Highlands and (Buried) Lowlands and Turn-Off of the Global Magnetic Field

    NASA Technical Reports Server (NTRS)

    Frey, H. V.

    2003-01-01

    The global populations of visible and buried impact basins greater than 200 km diameter revealed by high resolution gridded MOLA indicate: (a) a small (approximately 10) number of very large basins (D=1300-3000km), most of which have remained visible over martian history; (b) a much larger population of smaller basins (D=200-800 km) with many more buried than visible (on images); (c) a depletion of visible basins at intermediate diameters which may be a signature of some global-scale event (formation of the lowlands? origin of Tharsis?); and (d) a crater retention age for the buried lowlands greater than that of the visible highlands but less than that of the total (visible + buried) highlands. Crustal magnetic anomalies are generally not present in the interiors of the largest basins with two exceptions: these two (which appear to be the oldest) may predate the demise of the global magnetic field.

  14. Amorphous Silicon Based Neutron Detector

    SciTech Connect

    Xu, Liwei

    2004-12-12

    Various large-scale neutron sources already build or to be constructed, are important for materials research and life science research. For all these neutron sources, neutron detectors are very important aspect. However, there is a lack of a high-performance and low-cost neutron beam monitor that provides time and temporal resolution. The objective of this SBIR Phase I research, collaboratively performed by Midwest Optoelectronics, LLC (MWOE), the University of Toledo (UT) and Oak Ridge National Laboratory (ORNL), is to demonstrate the feasibility for amorphous silicon based neutron beam monitors that are pixilated, reliable, durable, fully packaged, and fabricated with high yield using low-cost method. During the Phase I effort, work as been focused in the following areas: 1) Deposition of high quality, low-defect-density, low-stress a-Si films using very high frequency plasma enhanced chemical vapor deposition (VHF PECVD) at high deposition rate and with low device shunting; 2) Fabrication of Si/SiO2/metal/p/i/n/metal/n/i/p/metal/SiO2/ device for the detection of alpha particles which are daughter particles of neutrons through appropriate nuclear reactions; and 3) Testing of various devices fabricated for alpha and neutron detection; As the main results: · High quality, low-defect-density, low-stress a-Si films have been successfully deposited using VHF PECVD on various low-cost substrates; · Various single-junction and double junction detector devices have been fabricated; · The detector devices fabricated have been systematically tested and analyzed. · Some of the fabricated devices are found to successfully detect alpha particles. Further research is required to bring this Phase I work beyond the feasibility demonstration toward the final prototype devices. The success of this project will lead to a high-performance, low-cost, X-Y pixilated neutron beam monitor that could be used in all of the neutron facilities worldwide. In addition, the technologies

  15. SURVIVAL OF AMORPHOUS WATER ICE ON CENTAURS

    SciTech Connect

    Guilbert-Lepoutre, Aurelie

    2012-10-01

    Centaurs are believed to be Kuiper Belt objects in transition between Jupiter and Neptune before possibly becoming Jupiter family comets. Some indirect observational evidence is consistent with the presence of amorphous water ice in Centaurs. Some of them also display a cometary activity, probably triggered by the crystallization of the amorphous water ice, as suggested by Jewitt and this work. Indeed, we investigate the survival of amorphous water ice against crystallization, using a fully three-dimensional thermal evolution model. Simulations are performed for varying heliocentric distances and obliquities. They suggest that crystallization can be triggered as far as 16 AU, though amorphous ice can survive beyond 10 AU. The phase transition is an efficient source of outgassing up to 10-12 AU, which is broadly consistent with the observations of the active Centaurs. The most extreme case is 167P/CINEOS, which barely crystallizes in our simulations. However, amorphous ice can be preserved inside Centaurs in many heliocentric distance-obliquity combinations, below a {approx}5-10 m crystallized crust. We also find that outgassing due to crystallization cannot be sustained for a time longer than 10{sup 4}-10{sup 4} years, leading to the hypothesis that active Centaurs might have recently suffered from orbital changes. This could be supported by both observations (although limited) and dynamical studies.

  16. Amorphous silicon detectors in positron emission tomography

    SciTech Connect

    Conti, M. Lawrence Berkeley Lab., CA ); Perez-Mendez, V. )

    1989-12-01

    The physics of the detection process is studied and the performances of different Positron Emission Tomography (PET) system are evaluated by theoretical calculation and/or Monte Carlo Simulation (using the EGS code) in this paper, whose table of contents can be summarized as follows: a brief introduction to amorphous silicon detectors and some useful equation is presented; a Tantalum/Amorphous Silicon PET project is studied and the efficiency of the systems is studied by Monte Carlo Simulation; two similar CsI/Amorphous Silicon PET projects are presented and their efficiency and spatial resolution are studied by Monte Carlo Simulation, light yield and time characteristics of the scintillation light are discussed for different scintillators; some experimental result on light yield measurements are presented; a Xenon/Amorphous Silicon PET is presented, the physical mechanism of scintillation in Xenon is explained, a theoretical estimation of total light yield in Xenon and the resulting efficiency is discussed altogether with some consideration of the time resolution of the system; the amorphous silicon integrated electronics is presented, total noise and time resolution are evaluated in each of our applications; the merit parameters {epsilon}{sup 2}{tau}'s are evaluated and compared with other PET systems and conclusions are drawn; and a complete reference list for Xenon scintillation light physics and its applications is presented altogether with the listing of the developed simulation programs.

  17. Use of XPS to clarify the Hall coefficient sign variation in thin niobium layers buried in silicon

    NASA Astrophysics Data System (ADS)

    Demchenko, Iraida N.; Lisowski, Wojciech; Syryanyy, Yevgen; Melikhov, Yevgen; Zaytseva, Iryna; Konstantynov, Pavlo; Chernyshova, Maryna; Cieplak, Marta Z.

    2017-03-01

    Si/Nb/Si trilayers formed with 9.5 and 1.3 nm thick niobium layer buried in amorphous silicon were prepared by magnetron sputtering and studied using XPS depth-profile techniques in order to investigate the change of Hall coefficient sign with thickness. The analysis of high-resolution (HR) XPS spectra revealed that the thicker layer sample has sharp top interface and metallic phase of niobium, thus holes dominate the transport. In contrast, the analysis indicates that the thinner layer sample has a Nb-rich mixed alloy formation at the top interface. The authors suggest that the main effect leading to a change of sign of the Hall coefficient for the thinner layer sample (which is negative contrary to the positive sign for the thicker layer sample) may be related to strong boundary scattering enhanced by the presence of silicon ions in the layer close to the interface/s. The depth-profile reconstruction was performed by SESSA software tool confirming that it can be reliably used for quantitative analysis/interpretation of experimental XPS data.

  18. Measure Guideline: Buried and/or Encapsulated Ducts

    SciTech Connect

    Shapiro, C.; Zoeller, W.; Mantha, P.

    2013-08-01

    Buried and/or encapsulated ducts (BEDs) are a class of advanced, energy-efficiency strategies intended to address the significant ductwork thermal losses associated with ducts installed in unconditioned attics. BEDs are ducts installed in unconditioned attics that are covered in loose-fill insulation and/or encapsulated in closed cell polyurethane spray foam insulation. This Measure Guideline covers the technical aspects of BEDs as well as the advantages, disadvantages, and risks of BEDs compared to other alternative strategies. This guideline also provides detailed guidance on installation of BEDs strategies in new and existing homes through step-by-step installation procedures. Some of the procedures presented here, however, require specialized equipment or expertise. In addition, some alterations to duct systems may require a specialized license.

  19. Solid state television camera (CCD-buried channel), revision 1

    NASA Technical Reports Server (NTRS)

    1977-01-01

    An all solid state television camera was designed which uses a buried channel charge coupled device (CCD) as the image sensor. A 380 x 488 element CCD array is utilized to ensure compatibility with 525-line transmission and display monitor equipment. Specific camera design approaches selected for study and analysis included (1) optional clocking modes for either fast (1/60 second) or normal (1/30 second) frame readout, (2) techniques for the elimination or suppression of CCD blemish effects, and (3) automatic light control and video gain control techniques to eliminate or minimize sensor overload due to bright objects in the scene. Preferred approaches were determined and integrated into a deliverable solid state TV camera which addressed the program requirements for a prototype qualifiable to space environment conditions.

  20. Solid state television camera (CCD-buried channel)

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The development of an all solid state television camera, which uses a buried channel charge coupled device (CCD) as the image sensor, was undertaken. A 380 x 488 element CCD array is utilized to ensure compatibility with 525 line transmission and display monitor equipment. Specific camera design approaches selected for study and analysis included (a) optional clocking modes for either fast (1/60 second) or normal (1/30 second) frame readout, (b) techniques for the elimination or suppression of CCD blemish effects, and (c) automatic light control and video gain control (i.e., ALC and AGC) techniques to eliminate or minimize sensor overload due to bright objects in the scene. Preferred approaches were determined and integrated into a deliverable solid state TV camera which addressed the program requirements for a prototype qualifiable to space environment conditions.

  1. External pipeline coating selection for new and existing buried pipelines

    SciTech Connect

    Brown, M.D.

    1996-12-31

    The majority of existing and new pipelines are externally coated. The opportunity to examine buried pipelines has shown that selection of both shop and over-the-ditch field applied coatings has resulted in many failures. Coating selection in 19896 has become more complex because of the abundance of available products. Not only are there many available coating types but there are also competitive products within each category. The safe approach is to select a coating that will perform well under the most severe conditions but this approach can be very costly and often a lesser coating is selected with the realization that it affects the risk of failure. This paper addresses the criteria that need to be considered during coating selection and provides an outline for the decision making process. Examples are used to illustrate the effect of different factors on coating performance.

  2. Ground-penetrating radar for buried mine detection

    SciTech Connect

    Sargis, P.D.; Lee, F.D.; Fulkerson, E.S.; McKinley, B.J.; Aimonetti, W.D.

    1994-04-01

    Lawrence Livermore National Laboratory (LLNL) is developing an ultra-wideband, side-looking, ground-penetrating impulse radar system that can be mounted on an airborne platform for the purpose of locating buried mines. The radar system is presently mounted on an 18-meter boom. The authors have successfully imaged a minefield located at the Nevada Test Site. The minefield consists of real and surrogate mines of various materials and sizes placed in natural vegetation. Some areas have been cleared for non-cluttered studies. A technical description of the system is presented, describing the wideband antennas, the video pulser, the receiver hardware, and the data acquisition system. The receiver and data acquisition hardware are off-the-shelf components. The data was processed using LLNL-developed image reconstruction software, and has been registered against the ground truth data. Images showing clearly visible mines, surface reference markers, and ground clutter are presented.

  3. Retrieval of Shape Characteristics for Buried Objects with GPR Monitoring

    NASA Astrophysics Data System (ADS)

    Soldovieri, F.; Comite, D.; Galli, A.; Valerio, G.; Barone, P. M.; Lauro, S. E.; Mattei, E.; Pettinelli, E.

    2012-04-01

    Information retrieval on the location and the geometrical features (dimensions and shape) of buried objects is of fundamental importance in geosciences areas involving environmental protection, mine clearance, archaeological investigations, space and planetary exploration, and so forth. Among the different non-invasive sensing techniques usually employed to achieve this kind of information, those based on ground-penetrating-radar (GPR) instruments are well-established and suitable to the mentioned purposes [1]. In this context, our interest in the present work is specifically focused on testing the potential performance of typical GPR instruments by means of appropriate data processing. It will be shown in particular to what extent the use of a suitable "microwave tomographic approach" [2] is able to furnish a shape estimation of the targets, possibly recognizing different kinds of canonical geometries, even having reduced cross sections and in critical conditions, where the scatterer size is comparable with resolution limits imposed by the usual measurement configurations. Our study starts by obtaining the typical "direct" information from the GPR techniques that is the scattered field in subsurface environments under the form of radargrams. In order to get a wide variety of scenarios for the operating conditions, this goal is achieved by means of two different and independent approaches [3]. One approach is based on direct measurements through an experimental laboratory setup: commercial GPR instruments (typically bistatic configurations operating around 1 GHz frequency range) are used to collect radargram profiles by investigating an artificial basin filled of liquid and/or granular materials (sand, etc.), in which targets (having different constitutive parameters, shape, and dimensions) can be buried. The other approach is based on numerical GPR simulations by means of a commercial CAD electromagnetic tool (CST), whose suitable implementation and data

  4. Buried paleosols of the Upper Paleolithic multilayered site Kostenki-1

    NASA Astrophysics Data System (ADS)

    Aparin, B. F.; Platonova, N. I.; Sukhacheva, E. Yu.; Dudin, A. E.

    2016-12-01

    The morphology and chemical and physicochemical properties of paleosols buried at the Upper Paleolithic multilayered site Kostenki-1 in Kostenki-Borshchevo district of Voronezh oblast were studied. Four in situ paleosols formed 20-40(45) ka ago were separated in the archaeological excavation. Together with the surface soils, they characterized two different epochs of pedogenesis—the interstadial and interglacial (Holocene) epochs—and three shorter cycles of pedogenesis. The traces of human occupation in the studied hollow in the Late Paleolithic were found in the layers corresponding to the interstadial epoch. The buried paleosols had a simple horizonation: A(W)-C. A shallow thickness of the soil profiles could be due to relatively short periods of pedogenesis and to the shallow embedding by the carbonate geochemical barrier. The degree of the organic matter humification in the paleosols varied from 0.6 to 1.5, which corresponded to the mean duration of the period of biological activity of 60 to 150 days per year characterizing the climatic conditions of the tundra, taiga, forest-steppe, and steppe natural zones. In the excavation Kostenki-1 (2004-2005), soil-sediment sequences composed of five series of lithological layers with soil layers on top of them were found. Their deposition proceeded in two phases—the water phase and the aerial phase—that predetermined the morphology and composition of the soil-sediment sequences. The history of sediment accumulation in the studied hollow consisted of five stages. Similar morphologies and compositions of the soil-sediment sequences corresponding to these stages attest to the cyclic pattern of their development. The stages of sedimentation and soil formation corresponded to cyclic climate fluctuations with changes in the temperature and moisture conditions. A comparative analysis of the morphology and properties of the paleosols and soil-sediment sequences made it possible to characterize the environmental

  5. Surface acoustic wave devices as passive buried sensors

    NASA Astrophysics Data System (ADS)

    Friedt, J.-M.; Rétornaz, T.; Alzuaga, S.; Baron, T.; Martin, G.; Laroche, T.; Ballandras, S.; Griselin, M.; Simonnet, J.-P.

    2011-02-01

    Surface acoustic wave (SAW) devices are currently used as passive remote-controlled sensors for measuring various physical quantities through a wireless link. Among the two main classes of designs—resonator and delay line—the former has the advantage of providing narrow-band spectrum informations and hence appears compatible with an interrogation strategy complying with Industry-Scientific-Medical regulations in radio-frequency (rf) bands centered around 434, 866, or 915 MHz. Delay-line based sensors require larger bandwidths as they consists of a few interdigitated electrodes excited by short rf pulses with large instantaneous energy and short response delays but is compatible with existing equipment such as ground penetrating radar (GPR). We here demonstrate the measurement of temperature using the two configurations, particularly for long term monitoring using sensors buried in soil. Although we have demonstrated long term stability and robustness of packaged resonators and signal to noise ratio compatible with the expected application, the interrogation range (maximum 80 cm) is insufficient for most geology or geophysical purposes. We then focus on the use of delay lines, as the corresponding interrogation method is similar to the one used by GPR which allows for rf penetration distances ranging from a few meters to tens of meters and which operates in the lower rf range, depending on soil water content, permittivity, and conductivity. Assuming propagation losses in a pure dielectric medium with negligible conductivity (snow or ice), an interrogation distance of about 40 m is predicted, which overcomes the observed limits met when using interrogation methods specifically developed for wireless SAW sensors, and could partly comply with the above-mentioned applications. Although quite optimistic, this estimate is consistent with the signal to noise ratio observed during an experimental demonstration of the interrogation of a delay line buried at a depth of 5

  6. SEM based overlay measurement between resist and buried patterns

    NASA Astrophysics Data System (ADS)

    Inoue, Osamu; Okagawa, Yutaka; Hasumi, Kazuhisa; Shao, Chuanyu; Leray, Philippe; Lorusso, Gian; Baudemprez, Bart

    2016-03-01

    With the continuous shrink in pattern size and increased density, overlay control has become one of the most critical issues in semiconductor manufacturing. Recently, SEM based overlay of AEI (After Etch Inspection) wafer has been used for reference and optimization of optical overlay (both Image Based Overlay (IBO) and Diffraction Based Overlay (DBO)). Overlay measurement at AEI stage contributes monitor and forecast the yield after formation by etch and calibrate optical measurement tools. however those overlay value seems difficult directly for feedback to a scanner. Therefore, there is a clear need to have SEM based overlay measurements of ADI (After Develop Inspection) wafers in order to serve as reference for optical overlay and make necessary corrections before wafers go to etch. Furthermore, to make the corrections as accurate as possible, actual device like feature dimensions need to be measured post ADI. This device size measurement is very unique feature of CDSEM , which can be measured with smaller area. This is currently possible only with the CD-SEM. This device size measurement is very unique feature of CD-SEM , which can be measured with smaller area. In this study, we assess SEM based overlay measurement of ADI and AEI wafer by using a sample from an N10 process flow. First, we demonstrate SEM based overlay performance at AEI by using dual damascene process for Via 0 (V0) and metal 1 (M1) layer. We also discuss the overlay measurements between litho-etch-litho stages of a triple patterned M1 layer and double pattern V0. Second, to illustrate the complexities in image acquisition and measurement we will measure overlay between M1B resist and buried M1A-Hard mask trench. Finally, we will show how high accelerating voltage can detect buried pattern information by BSE (Back Scattering Electron). In this paper we discuss the merits of this method versus standard optical metrology based corrections.

  7. Broadband infrared electro-optic modulator having a buried microstrip network

    NASA Technical Reports Server (NTRS)

    Cheo, Peter K. (Inventor); Gilden, Meyer (Inventor)

    1987-01-01

    A microwave infrared modulator having a novel three dimensional structure is presented. The modulator includes a waveguide and metal base with a dielectric wafer buried therebetween. The buried wafer allows for conventional microstrip structures to be employed with larger microstrip electrode dimensions than would otherwise be possible.

  8. 49 CFR 192.459 - External corrosion control: Examination of buried pipeline when exposed.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false External corrosion control: Examination of buried... Requirements for Corrosion Control § 192.459 External corrosion control: Examination of buried pipeline when... portion must be examined for evidence of external corrosion if the pipe is bare, or if the coating...

  9. 49 CFR 192.459 - External corrosion control: Examination of buried pipeline when exposed.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false External corrosion control: Examination of buried... Requirements for Corrosion Control § 192.459 External corrosion control: Examination of buried pipeline when... portion must be examined for evidence of external corrosion if the pipe is bare, or if the coating...

  10. 49 CFR 192.459 - External corrosion control: Examination of buried pipeline when exposed.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false External corrosion control: Examination of buried... Requirements for Corrosion Control § 192.459 External corrosion control: Examination of buried pipeline when... portion must be examined for evidence of external corrosion if the pipe is bare, or if the coating...

  11. Numerical Modeling of Mechanical Behavior for Buried Steel Pipelines Crossing Subsidence Strata

    PubMed Central

    Han, C. J.

    2015-01-01

    This paper addresses the mechanical behavior of buried steel pipeline crossing subsidence strata. The investigation is based on numerical simulation of the nonlinear response of the pipeline-soil system through finite element method, considering large strain and displacement, inelastic material behavior of buried pipeline and the surrounding soil, as well as contact and friction on the pipeline-soil interface. Effects of key parameters on the mechanical behavior of buried pipeline were investigated, such as strata subsidence, diameter-thickness ratio, buried depth, internal pressure, friction coefficient and soil properties. The results show that the maximum strain appears on the outer transition subsidence section of the pipeline, and its cross section is concave shaped. With the increasing of strata subsidence and diameter-thickness ratio, the out of roundness, longitudinal strain and equivalent plastic strain increase gradually. With the buried depth increasing, the deflection, out of roundness and strain of the pipeline decrease. Internal pressure and friction coefficient have little effect on the deflection of buried pipeline. Out of roundness is reduced and the strain is increased gradually with the increasing of internal pressure. The physical properties of soil have a great influence on the mechanical properties of buried pipeline. The results from the present study can be used for the development of optimization design and preventive maintenance for buried steel pipelines. PMID:26103460

  12. 49 CFR 192.459 - External corrosion control: Examination of buried pipeline when exposed.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false External corrosion control: Examination of buried... Requirements for Corrosion Control § 192.459 External corrosion control: Examination of buried pipeline when... portion must be examined for evidence of external corrosion if the pipe is bare, or if the coating...

  13. 49 CFR 192.459 - External corrosion control: Examination of buried pipeline when exposed.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false External corrosion control: Examination of buried... Requirements for Corrosion Control § 192.459 External corrosion control: Examination of buried pipeline when... portion must be examined for evidence of external corrosion if the pipe is bare, or if the coating...

  14. Numerical Modeling of Mechanical Behavior for Buried Steel Pipelines Crossing Subsidence Strata.

    PubMed

    Zhang, J; Liang, Z; Han, C J

    2015-01-01

    This paper addresses the mechanical behavior of buried steel pipeline crossing subsidence strata. The investigation is based on numerical simulation of the nonlinear response of the pipeline-soil system through finite element method, considering large strain and displacement, inelastic material behavior of buried pipeline and the surrounding soil, as well as contact and friction on the pipeline-soil interface. Effects of key parameters on the mechanical behavior of buried pipeline were investigated, such as strata subsidence, diameter-thickness ratio, buried depth, internal pressure, friction coefficient and soil properties. The results show that the maximum strain appears on the outer transition subsidence section of the pipeline, and its cross section is concave shaped. With the increasing of strata subsidence and diameter-thickness ratio, the out of roundness, longitudinal strain and equivalent plastic strain increase gradually. With the buried depth increasing, the deflection, out of roundness and strain of the pipeline decrease. Internal pressure and friction coefficient have little effect on the deflection of buried pipeline. Out of roundness is reduced and the strain is increased gradually with the increasing of internal pressure. The physical properties of soil have a great influence on the mechanical properties of buried pipeline. The results from the present study can be used for the development of optimization design and preventive maintenance for buried steel pipelines.

  15. 75 FR 32313 - Specifications and Drawings for Construction Direct Buried Plant

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-08

    ... Rural Utilities Service 7 CFR Part 1755 Specifications and Drawings for Construction Direct Buried Plant... Construction of Direct Buried Plant (Form 515a). The revised specification will include new construction units... to Michele Brooks, Director, Program Development and Regulatory Analysis, USDA-Rural...

  16. Amorphous metallic films in silicon metallization systems

    NASA Astrophysics Data System (ADS)

    So, F.; Kolawa, E.; Nicolet, M. A.

    1985-06-01

    Diffusion barrier research was focussed on lowering the chemical reactivity of amorphous thin films on silicon. An additional area of concern is the reaction with metal overlays such as aluminum, silver, and gold. Gold was included to allow for technology transfer to gallium arsenide PV cells. Amorphous tungsten nitride films have shown much promise. Stability to annealing temperatures of 700, 800, and 550 C were achieved for overlays of silver, gold, and aluminum, respectively. The lower results for aluminum were not surprising because there is an eutectic that can form at a lower temperature. It seems that titanium and zirconium will remove the nitrogen from a tungsten nitride amorphous film and render it unstable. Other variables of research interest were substrate bias and base pressure during sputtering.

  17. Nanocrystalline silicon/amorphous silicon dioxide superlattices

    SciTech Connect

    Fauchet, P.M.; Tsybeskov, L.; Zacharias, M. |; Hirschman, K. |

    1998-12-31

    Thin layers made of densely packed silicon nanocrystals sandwiched between amorphous silicon dioxide layers have been manufactured and characterized. An amorphous silicon/amorphous silicon dioxide superlattice is first grown by CVD or RF sputtering. The a-Si layers are recrystallized in a two-step procedure (nucleation + growth) for form layers of nearly identical nanocrystals whose diameter is given by the initial a-Si layer thickness. The recrystallization is monitored using a variety of techniques, including TEM, X-Ray, Raman, and luminescence spectroscopies. When the a-Si layer thickness decreases (from 25 nm to 2.5 nm) or the a-SiO{sub 2} layer thickness increases (from 1.5 nm to 6 nm), the recrystallization temperature increases dramatically compared to that of a single a-Si film. The removal of the a-Si tissue present between the nanocrystals, the passivation of the nanocrystals, and their doping are discussed.

  18. Phase transitions in biogenic amorphous calcium carbonate

    PubMed Central

    Gong, Yutao U. T.; Killian, Christopher E.; Olson, Ian C.; Appathurai, Narayana P.; Amasino, Audra L.; Martin, Michael C.; Holt, Liam J.; Wilt, Fred H.; Gilbert, P. U. P. A.

    2012-01-01

    Crystalline biominerals do not resemble faceted crystals. Current explanations for this property involve formation via amorphous phases. Using X-ray absorption near-edge structure (XANES) spectroscopy and photoelectron emission microscopy (PEEM), here we examine forming spicules in embryos of Strongylocentrotus purpuratus sea urchins, and observe a sequence of three mineral phases: hydrated amorphous calcium carbonate (ACC·H2O) → dehydrated amorphous calcium carbonate (ACC) → calcite. Unexpectedly, we find ACC·H2O-rich nanoparticles that persist after the surrounding mineral has dehydrated and crystallized. Protein matrix components occluded within the mineral must inhibit ACC·H2O dehydration. We devised an in vitro, also using XANES-PEEM, assay to identify spicule proteins that may play a role in stabilizing various mineral phases, and found that the most abundant occluded matrix protein in the sea urchin spicules, SM50, stabilizes ACC·H2O in vitro. PMID:22492931

  19. Amorphous metallic films in silicon metallization systems

    NASA Technical Reports Server (NTRS)

    So, F.; Kolawa, E.; Nicolet, M. A.

    1985-01-01

    Diffusion barrier research was focussed on lowering the chemical reactivity of amorphous thin films on silicon. An additional area of concern is the reaction with metal overlays such as aluminum, silver, and gold. Gold was included to allow for technology transfer to gallium arsenide PV cells. Amorphous tungsten nitride films have shown much promise. Stability to annealing temperatures of 700, 800, and 550 C were achieved for overlays of silver, gold, and aluminum, respectively. The lower results for aluminum were not surprising because there is an eutectic that can form at a lower temperature. It seems that titanium and zirconium will remove the nitrogen from a tungsten nitride amorphous film and render it unstable. Other variables of research interest were substrate bias and base pressure during sputtering.

  20. Amorphous/epitaxial superlattice for thermoelectric application

    NASA Astrophysics Data System (ADS)

    Ishida, Akihiro; Thao, Hoang Thi Xuan; Shibata, Mamoru; Nakashima, Seisuke; Tatsuoka, Hirokazu; Yamamoto, Hidenari; Kinoshita, Yohei; Ishikiriyama, Mamoru; Nakamura, Yoshiaki

    2016-08-01

    An amorphous/epitaxial superlattice system is proposed for application to thermoelectric devices, and the superlattice based on a PbGeTeS system was prepared by the alternate deposition of PbS and GeTe using a hot wall epitaxy technique. The structure was analyzed by high-resolution transmission electron microscopy (HRTEM) and X-ray analysis, and it was found that the superlattice consists of an epitaxial PbTe-based layer and a GeS-based amorphous layer by the reconstruction of the constituents. A reduction in thermal conductivity due to the amorphous/epitaxial system was confirmed by a 2ω method. Electrical and thermoelectric properties were measured for the samples.

  1. Predicting arsenic concentrations in the porewaters of buried uranium mill tailings

    NASA Astrophysics Data System (ADS)

    Langmuir, Donald; Mahoney, John; MacDonald, Anjali; Rowson, John

    1999-10-01

    The proposed JEB Tailings Management Facility (TMF) to be emplaced below the groundwater table in northern Saskatchewan, Canada, will contain uranium mill tailings from McClean Lake, Midwest and Cigar Lake ore bodies, which are high in arsenic (up to 10%) and nickel (up to 5%). A serious concern is the possibility that high arsenic and nickel concentrations may be released from the buried tailings, contaminating adjacent groundwaters and a nearby lake. Laboratory tests and geochemical modeling were performed to examine ways to reduce the arsenic and nickel concentrations in TMF porewaters so as to minimize such contamination from tailings buried for 50 years and longer. The tests were designed to mimic conditions in the mill neutralization circuit (3 hr tests at 25°C), and in the TMF after burial (5-49 day aging tests). The aging tests were run at, 50, 25 and 4°C (the temperature in the TMF). In order to optimize the removal of arsenic by adsorption and precipitation, ferric sulfate was added to tailings raffinates having Fe/As ratios of less that 3-5. The acid raffinates were then neutralized by addition of slaked lime to nominal pH values of 7, 8, or 9. Analysis and modeling of the test results showed that with slaked lime addition to acid tailings raffinates, relatively amorphous scorodite (ferric arsenate) precipitates near pH 1, and is the dominant form of arsenate in slake limed tailings solids except those high in Ni and As and low in Fe, in which cabrerite-annabergite (Ni, Mg, Fe(II) arsenate) may also precipitate near pH 5-6. In addition to the arsenate precipitates, smaller amounts of arsenate are also adsorbed onto tailings solids. The aging tests showed that after burial of the tailings, arsenic concentrations may increase with time from the breakdown of the arsenate phases (chiefly scorodite). However, the tests indicate that the rate of change decreases and approaches zero after 72 hrs at 25°C, and may equal zero at all times in the TMF at 4

  2. Buried topography of Utopia, Mars: Persistence of a giant impact depression

    SciTech Connect

    McGill, G.E. )

    1989-12-01

    Knobs, partially buried craters, ring fractures, and some mesas permit a qualitative determination of the topography buried beneath younger northern plains materials. These features are widely distributed in the Utopia area but are absent in a large, roughly circular region centered at about 48{degree}N, 240{degree}W. This implies the existence of a circular depression about 3,300 km in diameter buried beneath Utopia Planitia that is here interpreted to represent the central part of a very large impact basin. The presence of buried curved massifs around part of this depression, and a roughly coincident mascon, lend further support. Present topography, areal geology, and paleotopography of buried surfaces all point to the persistence of this major depression for almost the entire history of Mars.

  3. Contribution to classification of buried objects based on acoustic impedance matching.

    PubMed

    Stepanić, J; Wüstenberg, H; Krstelj, V; Mrasek, H

    2003-03-01

    Determination of material the buried objects are made of could contribute significantly to their recognition, or classification. This is important in detecting buried antipersonnel landmines within the context of humanitarian demining, as well as in a variety of other applications. In this article the concept has been formulated of the approach to buried object's material determination starting with ultrasonic impulse propagation analysis in a particular testing set configuration. The impulse propagates through a characterized transfer material in such a way that a part of it, a reflected wave, carries the information about the buried object's surface material acoustic impedance. The limit of resolution capability is theoretically analyzed and experimentally evaluated and the influencing factors described. Among these, the contact between clean surfaces of the transfer material and buried object is emphasized.

  4. Fast evaluation of Sommerfeld integrals for EM scattering and radiation by three-dimensional buried objects

    SciTech Connect

    Cui, T.J.; Chew, W.C.

    1999-03-01

    This paper presents a fast method for electromagnetic scattering and radiation problems pertinent to three-dimensional (3-D) buried objects. In this approach, a new symmetrical form of the Green`s function is derived, which can reduce the number of Sommerfeld integrals involved in the buried objects problem. The integration along steepest descent paths and leading-order approximations are introduced to evaluate these Sommerfeld integrals, which can greatly accelerate the computation. Based on the fast evaluation of Sommerfeld integrals, the radiation of an arbitrarily oriented electric dipole buried in a half space is first analyzed and computed. Then, the scattering by buried dielectric objects and conducting objects is considered using the method of moments (MOM). Numerical results show that the fast method can save tremendous CPU time in radiation and scattering problems involving buried objects.

  5. Buried topography of Utopia, Mars - Persistence of a giant impact depression

    NASA Technical Reports Server (NTRS)

    Mcgill, George E.

    1989-01-01

    Knobs, partially buried craters, ring fractures, and some mesas permit a qualitative determination of the topography buried beneath younger northern plains materials. These features are widely distributed in the Utopia area but are absent in a large, roughly circular region centered at about 48 deg N, 240 deg W. This implies the existence of a circular depression about 3300 km in diameter buried beneath Utopia Planitia that is interpreted to represent the central part of a very large impact basin. The presence of buried curved massifs around part of this depression, and a roughly coincident mascon, lend further support. Present topography, areal geology, and paleotopography of buried surfaces all point to the persistence of this major depression for almost the entire history of Mars.

  6. Atomic Bond Deficiency Defects in Amorphous Metals

    NASA Astrophysics Data System (ADS)

    Zhu, Aiwu; Shiflet, Gary J.; Poon, S. Joseph

    2012-10-01

    Atomic bond deficiency (BD) is considered to be characteristic structural defects in amorphous metals. They are the necessary feature of local atomic configurations that facilitate various atomic transports under different driving forces. Compared with vacancies in crystalline solids, they are "small" in terms of their formation energies, volume costs, and elementary steps involved in atomic transport. This article reviews the authors' recent efforts made to analyze how various local configurations containing BD are related to amorphous metal's unique characteristics, such as glass transition, diffusion, shear flow, and structural relaxation.

  7. Thermal conductivity of sputtered amorphous Ge films

    SciTech Connect

    Zhan, Tianzhuo; Xu, Yibin; Goto, Masahiro; Tanaka, Yoshihisa; Kato, Ryozo; Sasaki, Michiko; Kagawa, Yutaka

    2014-02-15

    We measured the thermal conductivity of amorphous Ge films prepared by magnetron sputtering. The thermal conductivity was significantly higher than the value predicted by the minimum thermal conductivity model and increased with deposition temperature. We found that variations in sound velocity and Ge film density were not the main factors in the high thermal conductivity. Fast Fourier transform patterns of transmission electron micrographs revealed that short-range order in the Ge films was responsible for their high thermal conductivity. The results provide experimental evidences to understand the underlying nature of the variation of phonon mean free path in amorphous solids.

  8. Neutron scattering studies of amorphous Invar alloys

    SciTech Connect

    Fernandez-Baca, J.A.

    1989-01-01

    This paper reviews recent inelastic neutron scattering experiments performed to study the spin dynamics of two amorphous Invar systems: Fe/sub 100-x/B/sub x/ and Fe/sub 90-x/Ni/sub x/Zr/sub 10/. As in crystalline Invar Fe/sub 65/Ni/sub 35/ and Fe/sub 3/Pt, the excitation of conventional long-wavelength spin waves in these amorphous systems cannot account for the relatively rapid change of their magnetization with temperature. These results are discussed in terms of additional low-lying excitations which apparently have a density of states similar to the spin waves.

  9. The effect of immersion time on burying depth of the bivalve Macoma balthica (Tellinidae)

    NASA Astrophysics Data System (ADS)

    de Goeij, Petra; Honkoop, Pieter J. C.

    2002-03-01

    As a characteristic buried tellinid bivalve, Macoma balthica has a long inhalent siphon that enables it to feed in two different ways: deposit and suspension feeding. To deposit feed efficiently on benthic microalgae, Macoma has to live close to the sediment surface, where it can graze an extensive surface area, but is within reach of many predators. Individuals that are more safely buried at a greater depth can only suspension feed, or deposit feed from a small surface area. We expected local differences in burying depth on intertidal mudflats to be caused by differences in immersion time (i.e. time available for feeding, particularly suspension feeding), since immersion time has been shown experimentally to affect body condition positively, and since body condition and burying depth in Macoma are postively related in the field. To test this we experimentally manipulated immersion time, and followed changes in burying depth and body condition. In the experiments, longer immersion time went consistently with greater burying depth of Macoma and higher body condition. On a transect in the western Wadden Sea, the deepest Macoma were indeed found at the intertidal level with the longest immersion time, but these were at that time not the animals with the highest body condition. Within each locality, however, body condition was positively correlated with burying depth. The experimental data and the within-locality data support the hypothesis that longer immersion time may influence burying depth through body condition. However, the fact that between-locality differences in burying depth seemed to be consistently related to immersion time, but not to body condition, indicates that body condition alone does not explain place-to-place variation in burying depth.

  10. Inverted amorphous silicon solar cell utilizing cermet layers

    DOEpatents

    Hanak, Joseph J.

    1979-01-01

    An amorphous silicon solar cell incorporating a transparent high work function metal cermet incident to solar radiation and a thick film cermet contacting the amorphous silicon opposite to said incident surface.

  11. Amorphization and nanocrystallization of silcon under shock compression

    SciTech Connect

    Remington, B. A.; Wehrenberg, C. E.; Zhao, S.; Hahn, E. N.; Kad, B.; Bringa, E. M.; Meyers, M. A.

    2015-11-06

    High-power, short-duration, laser-driven, shock compression and recovery experiments on [001] silicon unveiled remarkable structural changes above a pressure threshold. Two distinct amorphous regions were identified: (a) a bulk amorphous layer close to the surface and (b) amorphous bands initially aligned with {111} slip planes. Further increase of the laser energy leads to the re-crystallization of amorphous silicon into nanocrystals with high concentration of nano-twins. This amorphization is produced by the combined effect of high magnitude hydrostatic and shear stresses under dynamic shock compression. Shock-induced defects play a very important role in the onset of amorphization. Calculations of the free energy changes with pressure and shear, using the Patel-Cohen methodology, are in agreement with the experimental results. Molecular dynamics simulation corroborates the amorphization, showing that it is initiated by the nucleation and propagation of partial dislocations. As a result, the nucleation of amorphization is analyzed qualitatively by classical nucleation theory.

  12. Plasma deposition of amorphous metal alloys

    DOEpatents

    Hays, Auda K.

    1986-01-01

    Amorphous metal alloy coatings are plasma-deposited by dissociation of vapors of organometallic compounds and metalloid hydrides in the presence of a reducing gas, using a glow discharge. Tetracarbonylnickel, phosphine, and hydrogen constitute a typical reaction mixture of the invention, yielding a NiPC alloy.

  13. TRANSIENT AMORPHOUS CALCIUM PHOSPHATE IN FORMING ENAMEL

    PubMed Central

    Beniash, Elia; Metzler, Rebecca A.; Lam, Raymond S.K.; Gilbert, P.U.P.A.

    2009-01-01

    Enamel, the hardest tissue in the body, begins as a three-dimensional network of nanometer size mineral particles, suspended in a protein gel. This mineral network serves as a template for mature enamel formation. To further understand the mechanisms of enamel formation we characterized the forming enamel mineral at an early secretory stage using x-ray absorption near-edge structure (XANES) spectromicroscopy, transmission electron microscopy (TEM), FTIR microspectroscopy and polarized light microscopy. We show that the newly formed enamel mineral is amorphous calcium phosphate (ACP), which eventually transforms into apatitic crystals. Interestingly, the size, shape and spatial organization of these amorphous mineral particles and older crystals are essentially the same, indicating that the mineral morphology and organization in enamel is determined prior to its crystallization. Mineralization via transient amorphous phases has been previously reported in chiton teeth, mollusk shells, echinoderm spicules and spines, and recent reports strongly suggest the presence transient amorphous mineral in forming vertebrate bones. The present finding of transient ACP in murine tooth enamel suggests that this strategy might be universal. PMID:19217943

  14. High resolution amorphous silicon radiation detectors

    DOEpatents

    Street, Robert A.; Kaplan, Selig N.; Perez-Mendez, Victor

    1992-01-01

    A radiation detector employing amorphous Si:H cells in an array with each detector cell having at least three contiguous layers (n type, intrinsic, p type), positioned between two electrodes to which a bias voltage is applied. An energy conversion layer atop the silicon cells intercepts incident radiation and converts radiation energy to light energy of a wavelength to which the silicon cells are responsive. A read-out device, positioned proximate to each detector element in an array allows each such element to be interrogated independently to determine whether radiation has been detected in that cell. The energy conversion material may be a layer of luminescent material having a columnar structure. In one embodiment a column of luminescent material detects the passage therethrough of radiation to be detected and directs a light beam signal to an adjacent a-Si:H film so that detection may be confined to one or more such cells in the array. One or both electrodes may have a comb structure, and the teeth of each electrode comb may be interdigitated for capacitance reduction. The amorphous Si:H film may be replaced by an amorphous Si:Ge:H film in which up to 40 percent of the amorphous material is Ge. Two dimensional arrays may be used in X-ray imaging, CT scanning, crystallography, high energy physics beam tracking, nuclear medicine cameras and autoradiography.

  15. High resolution amorphous silicon radiation detectors

    DOEpatents

    Street, R.A.; Kaplan, S.N.; Perez-Mendez, V.

    1992-05-26

    A radiation detector employing amorphous Si:H cells in an array with each detector cell having at least three contiguous layers (n-type, intrinsic, p-type), positioned between two electrodes to which a bias voltage is applied. An energy conversion layer atop the silicon cells intercepts incident radiation and converts radiation energy to light energy of a wavelength to which the silicon cells are responsive. A read-out device, positioned proximate to each detector element in an array allows each such element to be interrogated independently to determine whether radiation has been detected in that cell. The energy conversion material may be a layer of luminescent material having a columnar structure. In one embodiment a column of luminescent material detects the passage therethrough of radiation to be detected and directs a light beam signal to an adjacent a-Si:H film so that detection may be confined to one or more such cells in the array. One or both electrodes may have a comb structure, and the teeth of each electrode comb may be interdigitated for capacitance reduction. The amorphous Si:H film may be replaced by an amorphous Si:Ge:H film in which up to 40 percent of the amorphous material is Ge. Two dimensional arrays may be used in X-ray imaging, CT scanning, crystallography, high energy physics beam tracking, nuclear medicine cameras and autoradiography. 18 figs.

  16. Plasma deposition of amorphous metal alloys

    DOEpatents

    Hays, A.K.

    1979-07-18

    Amorphous metal alloy coatings are plasma-deposited by dissociation of vapors of organometallic compounds and metalloid hydrides in the presence of a reducing gas, using a glow discharge. Tetracarbonylnickel, phosphine, and hydrogen constitute a typical reaction mixture of the invention, yielding a NiPC alloy.

  17. Structural modeling of amorphous conducting carbon film

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Somnath; Pati, Swapan K.; Subramanyam, S. V.

    1998-04-01

    Amorphous conducting carbon films are prepared using plasma assisted polymerization process. SEM and TEM shows random aggregate of globular clusters of micron size inside the samples. Electrical measurements indicate a near metallic nature. A tendency of saturation of resistivity at low temperature is observed. From spectroscopic analysis we find some unusual features. Based on these observations a structural model of this carbon is proposed.

  18. Low temperature internal friction of amorphous silicon

    NASA Astrophysics Data System (ADS)

    Liu, Xiao; Metcalf, Thomas; Jernigan, Glenn; Jugdersuren, Battogtokh; Kearney, Brian; Culberston, James

    The ubiquitous low-energy excitations, known as two-level tunnelling systems (TLS), are one of the universal phenomena of amorphous solids. These excitations dominate the acoustic, dielectric, and thermal properties of structurally disordered solids. Using the double-paddle oscillator internal friction measurement technique, we have shown that TLS can be made to almost completely disappear in e-beam deposited amorphous silicon (a-Si) as the growth temperature increased to 400°C. However, there is a mysterious broad maximum in internal friction at 2-3K, which we suspect to come from metallic contamination of our oscillators and is not related to a-Si. Our new result of a-Si, deposited in a different UHV system and on oscillators with a different type of metallic electrodes, confirms our suspicion. This lowers the upper bound of possible TLS content in a-Si, in terms of tunnelling strength, to below 10-6. Our results offer an encouraging opportunity to use growth temperature to improve the structure order of amorphous thin films and to develop high quality amorphous dielectrics for applications, such as in modern quantum devices. Work supported by the Office of Naval Research.

  19. Metal electrode for amorphous silicon solar cells

    DOEpatents

    Williams, Richard

    1983-01-01

    An amorphous silicon solar cell having an N-type region wherein the contact to the N-type region is composed of a material having a work function of about 3.7 electron volts or less. Suitable materials include strontium, barium and magnesium and rare earth metals such as gadolinium and yttrium.

  20. Amorphous Molecular Organic Solids for Gas Adsorption

    SciTech Connect

    Tian, Jian; Thallapally, Praveen K.; Dalgarno, Scott J.; McGrail, B. Peter; Atwood, Jerry L.

    2009-07-06

    We show that molecular organic compounds with large accessible internal cavities, as part of their rigid molecular structure, display exceptional ability for gas storage and separation in the amorphous solid state. This finding suggests for the first time that long-range molecular order is not a prerequisite for organic molecules to be engineered as porous materials

  1. Amorphous silica-like carbon dioxide

    NASA Astrophysics Data System (ADS)

    Santoro, Mario; Gorelli, Federico A.; Bini, Roberto; Ruocco, Giancarlo; Scandolo, Sandro; Crichton, Wilson A.

    2006-06-01

    Among the group IV elements, only carbon forms stable double bonds with oxygen at ambient conditions. At variance with silica and germania, the non-molecular single-bonded crystalline form of carbon dioxide, phase V, only exists at high pressure. The amorphous forms of silica (a-SiO2) and germania (a-GeO2) are well known at ambient conditions; however, the amorphous, non-molecular form of CO2 has so far been described only as a result of first-principles simulations. Here we report the synthesis of an amorphous, silica-like form of carbon dioxide, a-CO2, which we call `a-carbonia'. The compression of the molecular phase III of CO2 between 40 and 48GPa at room temperature initiated the transformation to the non-molecular amorphous phase. Infrared spectra measured at temperatures up to 680K show the progressive formation of C-O single bonds and the simultaneous disappearance of all molecular signatures. Furthermore, state-of-the-art Raman and synchrotron X-ray diffraction measurements on temperature-quenched samples confirm the amorphous character of the material. Comparison with vibrational and diffraction data for a-SiO2 and a-GeO2, as well as with the structure factor calculated for the a-CO2 sample obtained by first-principles molecular dynamics, shows that a-CO2 is structurally homologous to the other group IV dioxide glasses. We therefore conclude that the class of archetypal network-forming disordered systems, including a-SiO2, a-GeO2 and water, must be extended to include a-CO2.

  2. Bedrock mapping of buried valley networks using seismic reflection and airborne electromagnetic data

    NASA Astrophysics Data System (ADS)

    Oldenborger, G. A.; Logan, C. E.; Hinton, M. J.; Pugin, A. J.-M.; Sapia, V.; Sharpe, D. R.; Russell, H. A. J.

    2016-05-01

    In glaciated terrain, buried valleys often host aquifers that are significant groundwater resources. However, given the range of scales, spatial complexity and depth of burial, buried valleys often remain undetected or insufficiently mapped. Accurate and thorough mapping of bedrock topography is a crucial step in detecting and delineating buried valleys and understanding formative valley processes. We develop a bedrock mapping procedure supported by the combination of seismic reflection data and helicopter time-domain electromagnetic data with water well records for the Spiritwood buried valley aquifer system in Manitoba, Canada. The limited spatial density of water well bedrock observations precludes complete depiction of the buried valley bedrock topography and renders the water well records alone inadequate for accurate hydrogeological model building. Instead, we leverage the complementary strengths of seismic reflection and airborne electromagnetic data for accurate local detection of the sediment-bedrock interface and for spatially extensive coverage, respectively. Seismic reflection data are used to define buried valley morphology in cross-section beneath survey lines distributed over a regional area. A 3D model of electrical conductivity is derived from inversion of the airborne electromagnetic data and used to extrapolate buried valley morphology over the entire survey area. A spatially variable assignment of the electrical conductivity at the bedrock surface is applied to different features of the buried valley morphology identified in the seismic cross-sections. Electrical conductivity is then used to guide construction of buried valley shapes between seismic sections. The 3D locus of points defining each morphological valley feature is constructed using a path optimization routine that utilizes deviation from the assigned electrical conductivities as the cost function. Our resulting map represents a bedrock surface of unprecedented detail with more

  3. Buried targets in layered media: A combined finite element/physical acoustics model and comparison to data on a half buried 2:1 cylinder.

    PubMed

    Williams, Kevin L

    2016-12-01

    Previously, a combined finite element/physical acoustics model for proud targets [K. L. Williams, S. G. Kargl, E. I. Thorsos, D. S. Burnett, J. L. Lopes, M. Zampolli, and P. L. Marston, J. Acoust. Soc. Am. 127, 3356-3371 (2010)] was compared to both higher fidelity finite element models and to experimental data for a proud 2:1 aluminum cylinder. Here that expression is generalized to address the case of a target buried in a layered media. The result is compared to data acquired for the same 2:1 cylinder but half buried in a mud layer that covers the sand sediment (considered here as infinite in extent below the mud layer). The generalized expression reduces to both the previous proud result and to the result for a target buried in an infinite medium under the appropriate limiting conditions. The model/data comparisons shown include both the previous proud model and data results along with the ones for the half buried cylinder. The comparison quantifies the reduction in target strength as a function of frequency in the half buried case relative to the proud case.

  4. Buried Mesozoic rift basins of Moroccan Atlantic continental margin

    SciTech Connect

    Mohamed, N.; Jabour, H.; El Mostaine, M.

    1995-08-01

    The Atlantic continental margin is the largest frontier area for oil and gas exploration in Morocco. Most of the activity has been concentrated where Upper Jurassic carbonate rocks have been the drilling objectives, with only one significant but non commercial oil discovery. Recent exploration activities have focused on early Mesozoic Rift basins buried beneath the post-rift sediments of the Middle Atlantic coastal plain. Many of these basins are of interest because they contain fine-grained lacustrine rocks that have sufficient organic richness to be classified as efficient oil prone source rock. Location of inferred rift basins beneath the Atlantic coastal plain were determined by analysis of drilled-hole data in combination with gravity anomaly and aeromagnetic maps. These rift basins are characterized by several half graben filled by synrift sediments of Triassic age probably deposited in lacustrine environment. Coeval rift basins are known to be present in the U.S. Atlantic continental margin. Basin modeling suggested that many of the less deeply bored rift basins beneath the coastal plain are still within the oil window and present the most attractive exploration targets in the area.

  5. The Challenging Buried Bumper Syndrome after Percutaneous Endoscopic Gastrostomy

    PubMed Central

    Afifi, Ibrahim; Zarour, Ahmad; Al-Hassani, Ammar; Peralta, Ruben; El-Menyar, Ayman; Al-Thani, Hassan

    2016-01-01

    Buried bumper syndrome (BBS) is a rare complication developed after percutaneous endoscopic gastrostomy (PEG). We report a case of a 38-year-old male patient who sustained severe traumatic brain injury that was complicated with early BBS after PEG tube insertion. On admission, bedside PEG was performed, and 7 days later the patient developed signs of sepsis with rapid progression to septic shock and acute kidney injury. Abdominal CT scan revealed no collection or leakage of the contrast, but showed malpositioning of the tube bumper at the edge of the stomach and not inside of it. Diagnostic endoscopy revealed that the bumper was hidden in the posterolateral part of the stomach wall forming a tract inside of it, which confirmed the diagnosis of BBS. The patient underwent laparotomy with a repair of the stomach wall perforation, and the early postoperative course was uneventful. Acute BBS is a rare complication of PEG tube insertion which could be manifested with severe complications such as pressure necrosis, peritonitis and septic shock. Early identification is the mainstay to prevent such complications. Treatment selection is primarily guided by the presenting complications, ranging from simple endoscopic replacement to surgical laparotomy. PMID:27462190

  6. Detecting buried explosive hazards with handheld GPR and deep learning

    NASA Astrophysics Data System (ADS)

    Besaw, Lance E.

    2016-05-01

    Buried explosive hazards (BEHs), including traditional landmines and homemade improvised explosives, have proven difficult to detect and defeat during and after conflicts around the world. Despite their various sizes, shapes and construction material, ground penetrating radar (GPR) is an excellent phenomenology for detecting BEHs due to its ability to sense localized differences in electromagnetic properties. Handheld GPR detectors are common equipment for detecting BEHs because of their flexibility (in part due to the human operator) and effectiveness in cluttered environments. With modern digital electronics and positioning systems, handheld GPR sensors can sense and map variation in electromagnetic properties while searching for BEHs. Additionally, large-scale computers have demonstrated an insatiable appetite for ingesting massive datasets and extracting meaningful relationships. This is no more evident than the maturation of deep learning artificial neural networks (ANNs) for image and speech recognition now commonplace in industry and academia. This confluence of sensing, computing and pattern recognition technologies offers great potential to develop automatic target recognition techniques to assist GPR operators searching for BEHs. In this work deep learning ANNs are used to detect BEHs and discriminate them from harmless clutter. We apply these techniques to a multi-antennae, handheld GPR with centimeter-accurate positioning system that was used to collect data over prepared lanes containing a wide range of BEHs. This work demonstrates that deep learning ANNs can automatically extract meaningful information from complex GPR signatures, complementing existing GPR anomaly detection and classification techniques.

  7. Measure Guideline: Buried and/or Encapsulated Ducts

    SciTech Connect

    Shapiro, C.; Zoeller, W.; Mantha, P.

    2013-08-01

    Buried and/or encapsulated ducts (BEDs) are a class of advanced, energy-efficiency strategies intended to address the significant ductwork thermal losses associated with ducts installed in unconditioned attics. BEDs are ducts installed in unconditioned attics that are covered in loose-fill insulation and/or encapsulated in closed cell polyurethane spray foam insulation. This Measure Guideline covers the technical aspects of BEDs as well as the advantages, disadvantages, and risks of BEDs compared to other alternative strategies. This guideline also provides detailed guidance on installation of BEDs strategies in new and existing homes through step-by-step installation procedures. This Building America Measure Guideline synthesizes previously published research on BEDs and provides practical information to builders, contractors, homeowners, policy analysts, building professions, and building scientists. Some of the procedures presented here, however, require specialized equipment or expertise. In addition, some alterations to duct systems may require a specialized license. Persons implementing duct system improvements should not go beyond their expertise or qualifications. This guideline provides valuable information for a building industry that has struggled to address ductwork thermal losses in new and existing homes. As building codes strengthen requirements for duct air sealing and insulation, flexibility is needed to address energy efficiency goals. While ductwork in conditioned spaces has been promoted as the panacea for addressing ductwork thermal losses, BEDs installations approach - and sometimes exceed - the performance of ductwork in conditioned spaces.

  8. Responses of buried corrugated metal pipes to earthquakes

    SciTech Connect

    Davis, C.A.; Bardet, J.P.

    2000-01-01

    This study describes the results of field investigations and analyses carried out on 61 corrugated metal pipes (CMP) that were shaken by the 1994 Northridge earthquake. These CMPs, which include 29 small-diameter (below 107 cm) CMPs and 32 large-diameter (above 107 cm) CMPs, are located within a 10 km{sup 2} area encompassing the Van Normal Complex in the Northern San Fernando Valley, in Los Angeles, California. During the Northridge earthquake, ground movements were extensively recorded within the study area. Twenty-eight of the small-diameter CMPs performed well while the 32 large-diameter CMPs underwent performances ranging from no damage to complete collapse. The main cause of damage to the large-diameter CMPs was found to be the large ground strains. Based on this unprecedented data set, the factors controlling the seismic performance of the 32 large-diameter CMPs were identified and framed into a pseudostatic analysis method for evaluating the response of large diameter flexible underground pipes subjected to ground strain. The proposed analysis, which is applicable to transient and permanent strains, is capable of describing the observed performance of large-diameter CMPs during the 1994 Northridge earthquake. It indicates that peak ground velocity is a more reliable parameter for analyzing pipe damage than is peak ground acceleration. Results of this field investigation and analysis are useful for the seismic design and strengthening of flexible buried conduits.

  9. The Panther Mountain circular structure, a possible buried meteorite crater

    NASA Technical Reports Server (NTRS)

    Isachsen, Y. W.; Wright, S. F.; Revetta, F. A.; Duneen, R. J.

    1992-01-01

    Panther Mountain, located near Phoenicia, New York, is part of the Catskill Mountains, which form the eastern end of the Allegheny Plateau in New York. It is a circular mass defined physiographically by an anomalous circular drainage pattern produced by Esopus Creek and its tributary Woodland Creek. The circular valley that rings the mountain is fracture-controlled; where bedrock is exposed, it shows a joint density 5 to 10 times greater than that on either side of the valley. Where obscured by alluvial valley fill, the bedrock's low seismic velocity suggests that this anomalous fracturing is continuous in the bedrock underlying the rim valley. North-south and east-west gravity and magnetic profiles were made across the structure. Terrane-corrected, residual gravity profiles show an 18-mgal negative anomaly, and very steep gradients indicate a near-surface source. Several possible explanations of the gravity data were modeled. We conclude that the Panther Mountain circular structure is probably a buried meteorite crater that formed contemporaneously with marine or fluvial sedimentation during Silurian or Devonian time. An examination of drill core and cuttings in the region is underway to search for ejecta deposits and possible seismic and tsunami effects in the sedimentary section. Success would result in both dating the impact and furnishing a chronostratigraphic marker horizon.

  10. Parental care buffers against inbreeding depression in burying beetles

    PubMed Central

    Pilakouta, Natalie; Jamieson, Seonaidh; Moorad, Jacob A.; Smiseth, Per T.

    2015-01-01

    When relatives mate, their inbred offspring often suffer a reduction in fitness-related traits known as “inbreeding depression.” There is mounting evidence that inbreeding depression can be exacerbated by environmental stresses such as starvation, predation, parasitism, and competition. Parental care may play an important role as a buffer against inbreeding depression in the offspring by alleviating these environmental stresses. Here, we examine the effect of parental care on the fitness costs of inbreeding in the burying beetle Nicrophorus vespilloides, an insect with facultative parental care. We used a 2 × 2 factorial design with the following factors: (i) the presence or absence of a caring female parent during larval development and (ii) inbred or outbred offspring. We examined the joint influence of maternal care and inbreeding status on fitness-related offspring traits to test the hypothesis that maternal care improves the performance of inbred offspring more than that of outbred offspring. Indeed, the female's presence led to a higher increase in larval survival in inbred than in outbred broods. Receiving care at the larval stage also increased the lifespan of inbred but not outbred adults, suggesting that the beneficial buffering effects of maternal care can persist long after the offspring have become independent. Our results show that parental care has the potential to moderate the severity of inbreeding depression, which in turn may favor inbreeding tolerance and influence the evolution of mating systems and other inbreeding-avoidance mechanisms. PMID:26080412

  11. Thermal processing system concepts and considerations for RWMC buried waste

    SciTech Connect

    Eddy, T.L.; Kong, P.C.; Raivo, B.D.; Anderson, G.L.

    1992-02-01

    This report presents a preliminary determination of ex situ thermal processing system concepts and related processing considerations for application to remediation of transuranic (TRU)-contaminated buried wastes (TRUW) at the Radioactive Waste Management Complex (RWMC) of the Idaho National Engineering Laboratory (INEL). Beginning with top-level thermal treatment concepts and requirements identified in a previous Preliminary Systems Design Study (SDS), a more detailed consideration of the waste materials thermal processing problem is provided. Anticipated waste stream elements and problem characteristics are identified and considered. Final waste form performance criteria, requirements, and options are examined within the context of providing a high-integrity, low-leachability glass/ceramic, final waste form material. Thermal processing conditions required and capability of key systems components (equipment) to provide these material process conditions are considered. Information from closely related companion study reports on melter technology development needs assessment and INEL Iron-Enriched Basalt (IEB) research are considered. Five potentially practicable thermal process system design configuration concepts are defined and compared. A scenario for thermal processing of a mixed waste and soils stream with essentially no complex presorting and using a series process of incineration and high temperature melting is recommended. Recommendations for applied research and development necessary to further detail and demonstrate the final waste form, required thermal processes, and melter process equipment are provided.

  12. Parental care buffers against inbreeding depression in burying beetles.

    PubMed

    Pilakouta, Natalie; Jamieson, Seonaidh; Moorad, Jacob A; Smiseth, Per T

    2015-06-30

    When relatives mate, their inbred offspring often suffer a reduction in fitness-related traits known as "inbreeding depression." There is mounting evidence that inbreeding depression can be exacerbated by environmental stresses such as starvation, predation, parasitism, and competition. Parental care may play an important role as a buffer against inbreeding depression in the offspring by alleviating these environmental stresses. Here, we examine the effect of parental care on the fitness costs of inbreeding in the burying beetle Nicrophorus vespilloides, an insect with facultative parental care. We used a 2 × 2 factorial design with the following factors: (i) the presence or absence of a caring female parent during larval development and (ii) inbred or outbred offspring. We examined the joint influence of maternal care and inbreeding status on fitness-related offspring traits to test the hypothesis that maternal care improves the performance of inbred offspring more than that of outbred offspring. Indeed, the female's presence led to a higher increase in larval survival in inbred than in outbred broods. Receiving care at the larval stage also increased the lifespan of inbred but not outbred adults, suggesting that the beneficial buffering effects of maternal care can persist long after the offspring have become independent. Our results show that parental care has the potential to moderate the severity of inbreeding depression, which in turn may favor inbreeding tolerance and influence the evolution of mating systems and other inbreeding-avoidance mechanisms.

  13. Detection of Buried Human Remains Using Bioreporter Fluorescence

    SciTech Connect

    Vass, A. Dr.; Singleton, G. B.

    2001-10-01

    The search for buried human remains is a difficult, laborious and time-consuming task for law enforcement agencies. This study was conducted as a proof of principle demonstration to test the concept of using bioreporter microorganisms as a means to cover large areas in such a search. These bioreporter microorganisms are affected by a particular component of decaying organic matter that is distinct from decaying vegetation. The diamino compounds cadaverine and putrescine were selected as target compounds for the proof-of-principle investigation, and a search for microorganisms and genes that are responsive to either of these compounds was conducted. One recombinant clone was singled out for characterization based on its response to putrescine. The study results show that small concentrations of putrescine increased expression from this bioreporter construct. Although the level of increase was small (making it difficult to distinguish the signal from background), the results demonstrate the principle that bioreporters can be used to detect compounds resulting from decaying human remains and suggest that a wider search for target compounds should be conducted.

  14. The Challenging Buried Bumper Syndrome after Percutaneous Endoscopic Gastrostomy.

    PubMed

    Afifi, Ibrahim; Zarour, Ahmad; Al-Hassani, Ammar; Peralta, Ruben; El-Menyar, Ayman; Al-Thani, Hassan

    2016-01-01

    Buried bumper syndrome (BBS) is a rare complication developed after percutaneous endoscopic gastrostomy (PEG). We report a case of a 38-year-old male patient who sustained severe traumatic brain injury that was complicated with early BBS after PEG tube insertion. On admission, bedside PEG was performed, and 7 days later the patient developed signs of sepsis with rapid progression to septic shock and acute kidney injury. Abdominal CT scan revealed no collection or leakage of the contrast, but showed malpositioning of the tube bumper at the edge of the stomach and not inside of it. Diagnostic endoscopy revealed that the bumper was hidden in the posterolateral part of the stomach wall forming a tract inside of it, which confirmed the diagnosis of BBS. The patient underwent laparotomy with a repair of the stomach wall perforation, and the early postoperative course was uneventful. Acute BBS is a rare complication of PEG tube insertion which could be manifested with severe complications such as pressure necrosis, peritonitis and septic shock. Early identification is the mainstay to prevent such complications. Treatment selection is primarily guided by the presenting complications, ranging from simple endoscopic replacement to surgical laparotomy.

  15. Climate-mediated cooperation promotes niche expansion in burying beetles.

    PubMed

    Sun, Syuan-Jyun; Rubenstein, Dustin R; Chen, Bo-Fei; Chan, Shih-Fan; Liu, Jian-Nan; Liu, Mark; Hwang, Wenbe; Yang, Ping-Shih; Shen, Sheng-Feng

    2014-05-13

    The ability to form cooperative societies may explain why humans and social insects have come to dominate the earth. Here we examine the ecological consequences of cooperation by quantifying the fitness of cooperative (large groups) and non-cooperative (small groups) phenotypes in burying beetles (Nicrophorus nepalensis) along an elevational and temperature gradient. We experimentally created large and small groups along the gradient and manipulated interspecific competition with flies by heating carcasses. We show that cooperative groups performed as thermal generalists with similarly high breeding success at all temperatures and elevations, whereas non-cooperative groups performed as thermal specialists with higher breeding success only at intermediate temperatures and elevations. Studying the ecological consequences of cooperation may not only help us to understand why so many species of social insects have conquered the earth, but also to determine how climate change will affect the success of these and other social species, including our own.DOI: http://dx.doi.org/10.7554/eLife.02440.001.

  16. Imaging of buried phosphorus nanostructures in silicon using scanning tunneling microscopy

    SciTech Connect

    Oberbeck, Lars; Reusch, Thilo C. G.; Hallam, Toby; Simmons, Michelle Y. E-mail: michelle.simmons@unsw.edu.au; Schofield, Steven R.; Curson, Neil J. E-mail: michelle.simmons@unsw.edu.au

    2014-06-23

    We demonstrate the locating and imaging of single phosphorus atoms and phosphorus dopant nanostructures, buried beneath the Si(001) surface using scanning tunneling microscopy. The buried dopant nanostructures have been fabricated in a bottom-up approach using scanning tunneling microscope lithography on Si(001). We find that current imaging tunneling spectroscopy is suited to locate and image buried nanostructures at room temperature and with residual surface roughness present. From these studies, we can place an upper limit on the lateral diffusion during encapsulation with low-temperature Si molecular beam epitaxy.

  17. The study of buried drift aquifers in Minnesota by seismic geophysical methods

    USGS Publications Warehouse

    Woodward, D. G.

    1984-01-01

    Buried-drift aquifers are stratified sand and (or) gravel aquifers in glacial deposits that cannot be seen or inferred at the land surface. During the Pleistocene Epoch, four continental glaciations advanced and retreated across Minnesota, blanketing the bedrock surface with drift as much as 700 feet thick (fig. 1). Most of the drift consists of till, an unsorted, un-stratified mixture of clay silt, sand, and gravel that usually is not considered to be an aquifer. Permeable, stratified sand and gravel, deposited as outwash, alluvium, and (or) ice-contact deposits usually during an earlier glacial episode and subsequently covered (buried) with till, form the buried-drift aquifers.

  18. Fabricating amorphous silicon solar cells by varying the temperature _of the substrate during deposition of the amorphous silicon layer

    DOEpatents

    Carlson, David E.

    1982-01-01

    An improved process for fabricating amorphous silicon solar cells in which the temperature of the substrate is varied during the deposition of the amorphous silicon layer is described. Solar cells manufactured in accordance with this process are shown to have increased efficiencies and fill factors when compared to solar cells manufactured with a constant substrate temperature during deposition of the amorphous silicon layer.

  19. Defect-induced solid state amorphization of molecular crystals

    NASA Astrophysics Data System (ADS)

    Lei, Lei; Carvajal, Teresa; Koslowski, Marisol

    2012-04-01

    We investigate the process of mechanically induced amorphization in small molecule organic crystals under extensive deformation. In this work, we develop a model that describes the amorphization of molecular crystals, in which the plastic response is calculated with a phase field dislocation dynamics theory in four materials: acetaminophen, sucrose, γ-indomethacin, and aspirin. The model is able to predict the fraction of amorphous material generated in single crystals for a given applied stress. Our results show that γ-indomethacin and sucrose demonstrate large volume fractions of amorphous material after sufficient plastic deformation, while smaller amorphous volume fractions are predicted in acetaminophen and aspirin, in agreement with experimental observation.

  20. Atomic-scale disproportionation in amorphous silicon monoxide

    PubMed Central

    Hirata, Akihiko; Kohara, Shinji; Asada, Toshihiro; Arao, Masazumi; Yogi, Chihiro; Imai, Hideto; Tan, Yongwen; Fujita, Takeshi; Chen, Mingwei

    2016-01-01

    Solid silicon monoxide is an amorphous material which has been commercialized for many functional applications. However, the amorphous structure of silicon monoxide is a long-standing question because of the uncommon valence state of silicon in the oxide. It has been deduced that amorphous silicon monoxide undergoes an unusual disproportionation by forming silicon- and silicon-dioxide-like regions. Nevertheless, the direct experimental observation is still missing. Here we report the amorphous structure characterized by angstrom-beam electron diffraction, supplemented by synchrotron X-ray scattering and computer simulations. In addition to the theoretically predicted amorphous silicon and silicon-dioxide clusters, suboxide-type tetrahedral coordinates are detected by angstrom-beam electron diffraction at silicon/silicon-dioxide interfaces, which provides compelling experimental evidence on the atomic-scale disproportionation of amorphous silicon monoxide. Eventually we develop a heterostructure model of the disproportionated silicon monoxide which well explains the distinctive structure and properties of the amorphous material. PMID:27172815

  1. Amorphous-crystalline transition in thermoelectric NbO2

    NASA Astrophysics Data System (ADS)

    Music, Denis; Chen, Yen-Ting; Bliem, Pascal; Geyer, Richard W.

    2015-06-01

    Density functional theory was employed to design enhanced amorphous NbO2 thermoelectrics. The covalent-ionic nature of Nb-O bonding is identical in amorphous NbO2 and its crystalline counterpart. However, the Anderson localisation occurs in amorphous NbO2, which may affect the transport properties. We calculate a multifold increase in the absolute Seebeck coefficient for the amorphous state. These predictions were critically appraised by measuring the Seebeck coefficient of sputtered amorphous and crystalline NbO2 thin films with the identical short-range order. The first-order phase transition occurs at approximately 550 °C, but amorphous NbO2 possesses enhanced transport properties at all temperatures. Amorphous NbO2, reaching  -173 μV K-1, exhibits up to a 29% larger absolute Seebeck coefficient value, thereby validating the predictions.

  2. Atomic-scale disproportionation in amorphous silicon monoxide.

    PubMed

    Hirata, Akihiko; Kohara, Shinji; Asada, Toshihiro; Arao, Masazumi; Yogi, Chihiro; Imai, Hideto; Tan, Yongwen; Fujita, Takeshi; Chen, Mingwei

    2016-05-13

    Solid silicon monoxide is an amorphous material which has been commercialized for many functional applications. However, the amorphous structure of silicon monoxide is a long-standing question because of the uncommon valence state of silicon in the oxide. It has been deduced that amorphous silicon monoxide undergoes an unusual disproportionation by forming silicon- and silicon-dioxide-like regions. Nevertheless, the direct experimental observation is still missing. Here we report the amorphous structure characterized by angstrom-beam electron diffraction, supplemented by synchrotron X-ray scattering and computer simulations. In addition to the theoretically predicted amorphous silicon and silicon-dioxide clusters, suboxide-type tetrahedral coordinates are detected by angstrom-beam electron diffraction at silicon/silicon-dioxide interfaces, which provides compelling experimental evidence on the atomic-scale disproportionation of amorphous silicon monoxide. Eventually we develop a heterostructure model of the disproportionated silicon monoxide which well explains the distinctive structure and properties of the amorphous material.

  3. Near-field synthetic aperture imaging of buried objects and fluids

    NASA Astrophysics Data System (ADS)

    Nilles, James T.; Tricoles, Gus P.; Vance, Gary L.

    1995-06-01

    This paper describes imaging of buried objects and fluids. The motivations are to locate pipe leakage and unexploded ordnance. The method is to radiate and receive continuous, discrete frequency radio waves with antennas near the ground, to synthesize sampled area arrays of reflectance data, and to process the data into images with an algorithm based on angular spectrum diffraction theory. Experimental results are presented for three setups. An initial, laboratory setup had a single, spatially scanned antenna; it was used to image buried mud. The second with an array of five antennas on a vehicle, images a buried creosote pit. The third, with a vehicular array of seven antennas, imaged buried metallic objects and depressions in the soil surface.

  4. View northeast, timber groin mostly buried in sand U.S. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View northeast, timber groin mostly buried in sand - U.S. Coast Guard Sandy Hook Station, Western Docking Structure, West of intersection of Canfield Road & Hartshorne Drive, Highlands, Monmouth County, NJ

  5. Building America Top Innovations 2013 Profile – Buried and Encapsulated Ducts

    SciTech Connect

    none,

    2013-09-01

    In this innovation profile, CARB research shows HVAC ducts that are encapsulated in closed-cell spray foam and buried in blown insulation in a vented attic meet the code requirements for ducts in conditioned space.

  6. Thermoluminescence characteristics of hydrogenated amorphous zirconia

    NASA Astrophysics Data System (ADS)

    Montalvo, T. R.; Tenorio, L. O.; Nieto, J. A.; Salgado, M. B.; Estrada, A. M. S.; Furetta, C.

    2005-05-01

    This paper reports the experimental results concerning the thermoluminescent (TL) characteristics of hydrogenated amorphous zirconium oxide (a-Zr:H) powder prepared by the sol-gel method. The advantages of this method are the homogeneity and the purity of the gels associated with a relatively low sintering temperature. Hydrogenated amorphous powder was characterized by thermal analysis and X-ray diffraction. The main TL characteristics investigated were the TL response as a function of the absorbed dose, the reproducibility of the TL readings and the fading. The undoped a-Zr:H powder presents a TL glow curve with two peaks centered at 150 and 260 degrees C, respectively, after beta irradiation. The TL response a-Zr:H as a function of the absorbed dose showed a linear behavior over a wide range. The results presented open the possibility to use this material as a good TL dosimeter.

  7. Computer models for amorphous silicon hydrides

    NASA Astrophysics Data System (ADS)

    Mousseau, Normand; Lewis, Laurent J.

    1990-02-01

    A procedure for generating fully coordinated model structures appropriate to hydrogenated amorphous semiconductors is described. The hydrogen is incorporated into an amorphous matrix using a bond-switching process similar to that proposed by Wooten, Winer, and Weaire, which ensures that fourfold coordination is preserved. After each inclusion of hydrogen, the structure is relaxed using a finite-temperature Monte Carlo algorithm. The method is applied to a-Si:H at various hydrogen concentrations. The resulting model structures are found to be in excellent agreement with recent neutron-scattering measurements on a sample with 12 at. % H. Our prescription, which is essentially nonlocal, allows great flexibility and can easily be extended to related systems.

  8. Wear Resistant Amorphous and Nanocomposite Coatings

    SciTech Connect

    Racek, O

    2008-03-26

    Glass forming materials (critical cooling rate <10{sup 4}K.s{sup -1}) are promising for their high corrosion and wear resistance. During rapid cooling, the materials form an amorphous structure that transforms to nanocrystalline during a process of devitrification. High hardness (HV 1690) can be achieved through a controlled crystallization. Thermal spray process has been used to apply coatings, which preserves the amorphous/nanocomposite structure due to a high cooling rate of the feedstock particles during the impact on a substrate. Wear properties have been studied with respect to process conditions and feedstock material properties. Application specific properties such as sliding wear resistance have been correlated with laboratory tests based on instrumented indentation and scratch tests.

  9. Structural characterization of stable amorphous silicon films

    NASA Astrophysics Data System (ADS)

    Zhang, Shibin; Kong, Guanglin; Wang, Yongqian; Sheng, Shuran; Liao, Xianbo

    2002-05-01

    A kind of hydrogenated diphasic silicon films has been prepared by a new regime of plasma enhanced chemical vapor deposition (PECVD) in the region adjacent to the phase transition from amorphous to crystalline state. The photoelectronic and microstructural properties of the films have been investigated by the constant photocurrent method (CPM), Raman scattering and nuclear magnetic resonance (NMR). Our experimental results and corresponding analyses showed that the diphasic films, incorporated with a subtle boron compensation, could gain both the fine photosensitivity and high stability, provided the crystalline fraction ( f) was controlled in the range of 0< f<0.3. When compared with the conventional hydrogenated amorphous silicon (a-Si:H), the diphasic films are more ordered and robust in the microstructure, and have a less clustered phase in the Si-H bond configurations.

  10. Reversibility and criticality in amorphous solids

    DOE PAGES

    Regev, Ido; Weber, John; Reichhardt, Charles; ...

    2015-11-13

    The physical processes governing the onset of yield, where a material changes its shape permanently under external deformation, are not yet understood for amorphous solids that are intrinsically disordered. Here, using molecular dynamics simulations and mean-field theory, we show that at a critical strain amplitude the sizes of clusters of atoms undergoing cooperative rearrangements of displacements (avalanches) diverges. We compare this non-equilibrium critical behaviour to the prevailing concept of a ‘front depinning’ transition that has been used to describe steady-state avalanche behaviour in different materials. We explain why a depinning-like process can result in a transition from periodic to chaoticmore » behaviour and why chaotic motion is not possible in pinned systems. As a result, these findings suggest that, at least for highly jammed amorphous systems, the irreversibility transition may be a side effect of depinning that occurs in systems where the disorder is not quenched.« less

  11. Reversibility and criticality in amorphous solids

    SciTech Connect

    Regev, Ido; Weber, John; Reichhardt, Charles; Dahmen, Karin A.; Lookman, Turab

    2015-11-13

    The physical processes governing the onset of yield, where a material changes its shape permanently under external deformation, are not yet understood for amorphous solids that are intrinsically disordered. Here, using molecular dynamics simulations and mean-field theory, we show that at a critical strain amplitude the sizes of clusters of atoms undergoing cooperative rearrangements of displacements (avalanches) diverges. We compare this non-equilibrium critical behaviour to the prevailing concept of a ‘front depinning’ transition that has been used to describe steady-state avalanche behaviour in different materials. We explain why a depinning-like process can result in a transition from periodic to chaotic behaviour and why chaotic motion is not possible in pinned systems. As a result, these findings suggest that, at least for highly jammed amorphous systems, the irreversibility transition may be a side effect of depinning that occurs in systems where the disorder is not quenched.

  12. Breakdown of elasticity in amorphous solids

    NASA Astrophysics Data System (ADS)

    Biroli, Giulio; Urbani, Pierfrancesco

    2016-12-01

    What characterizes a solid is the way that it responds to external stresses. Ordered solids, such as crystals, exhibit an elastic regime followed by a plastic regime, both understood microscopically in terms of lattice distortion and dislocations. For amorphous solids the situation is instead less clear, and the microscopic understanding of the response to deformation and stress is a very active research topic. Several studies have revealed that even in the elastic regime the response is very jerky at low temperature, resembling very much the response of disordered magnetic materials. Here we show that in a very large class of amorphous solids this behaviour emerges upon decreasing temperature, as a phase transition, where standard elastic behaviour breaks down. At the transition all nonlinear elastic moduli diverge and standard elasticity theory no longer holds. Below the transition, the response to deformation becomes history- and time-dependent.

  13. Disappearance and Creation of Constrained Amorphous Phase

    NASA Astrophysics Data System (ADS)

    Cebe, Peggy; Lu, Sharon X.

    1997-03-01

    We report observation of the disappearance and recreation of rigid, or constrained, amorphous phase by sequential thermal annealing. Tempera- ture modulated differential scanning calorimetry (MDSC) is used to study the glass transition and lower melting endotherm after annealing. Cold crystallization of poly(phenylene sulfide), PPS, at a temperature just above Tg creates an initial large fraction of rigid amorphous phase (RAP). Brief, rapid annealing to a higher temperature causes RAP almost to disappear completely. Subsequent reannealing at the original lower temperature restores RAP to its original value. At the same time that RAP is being removed, Tg decreases; when RAP is restored, Tg also returns to its initial value. The crystal fraction remains unaffected by the annealing sequence.

  14. Germanium detector passivated with hydrogenated amorphous germanium

    DOEpatents

    Hansen, William L.; Haller, Eugene E.

    1986-01-01

    Passivation of predominantly crystalline semiconductor devices (12) is provided for by a surface coating (21) of sputtered hydrogenated amorphous semiconductor material. Passivation of a radiation detector germanium diode, for example, is realized by sputtering a coating (21) of amorphous germanium onto the etched and quenched diode surface (11) in a low pressure atmosphere of hydrogen and argon. Unlike prior germanium diode semiconductor devices (12), which must be maintained in vacuum at cryogenic temperatures to avoid deterioration, a diode processed in the described manner may be stored in air at room temperature or otherwise exposed to a variety of environmental conditions. The coating (21) compensates for pre-existing undesirable surface states as well as protecting the semiconductor device (12) against future impregnation with impurities.

  15. Annealing behavior of high permeability amorphous alloys

    SciTech Connect

    Rabenberg, L.

    1980-06-01

    Effects of low temperature annealing on the magnetic properties of the amorphous alloy Co/sub 71/ /sub 4/Fe/sub 4/ /sub 6/Si/sub 9/ /sub 6/B/sub 14/ /sub 4/ were investigated. Annealing this alloy below 400/sup 0/C results in magnetic hardening; annealing above 400/sup 0/C but below the crystallization temperature results in magnetic softening. Above the crystallization temperature the alloy hardens drastically and irreversibly. Conventional and high resolution transmission electron microscopy were used to show that the magnetic property changes at low temperatures occur while the alloy is truly amorphous. By imaging the magnetic microstructures, Lorentz electron microscopy has been able to detect the presence of microscopic inhomogeneities in this alloy. The low temperature annealing behavior of this alloy has been explained in terms of atomic pair ordering in the presence of the internal molecular field. Lorentz electron microscopy has been used to confirm this explanation.

  16. Phonon stop bands in amorphous superlattices

    NASA Astrophysics Data System (ADS)

    Koblinger, O.; Mebert, J.; Dittrich, E.; Döttinger, S.; Eisenmenger, W.; Santos, P. V.; Ley, L.

    1987-06-01

    In periodically layered media the phonon-dispersion relation shows energy ranges in which phonon propagation is not possible. The existence of such phonon stop bands in crystalline superlattices has been observed in work by V. Narayanamurti, H. L. Störmer, M. A. Chin, A. C. Gossard, and W. Wiegman [Phys. Rev. Lett. 43, 2012 (1979)]. In this Communication we report the observation of phonon stop bands in amorphous superlattices. The filter characteristic of these amorphous superlattices is much sharper than in the case of the crystalline superlattices studied earlier. The investigated superlattices have been prepared by alternating evaporation of Si and SiO2 layers as well as by plasma-enhanced chemical vapor deposition of a-Si:H/a-SiNx:H films in a glow-discharge reactor.

  17. New transformations between crystalline and amorphous ice

    NASA Technical Reports Server (NTRS)

    Hemley, R. J.; Chen, L. C.; Mao, H. K.

    1989-01-01

    High-pressure optical and spectroscopic techniques were used to obtain directly the ice I(h) - hda-ice transformation in a diamond-anvil cell, and the stability of the amorphous form is examined as functions of pressure and temperature. It is demonstrated that hda-ice transforms abruptly at 4 GPa and 77 K to a crystalline phase close in structure to orientationally disordered ice-VII and to a more highly ordered, ice-VIII-like structure at higher temperatures. This is the first time that an amorphous solid is observed to convert to a crystalline solid at low temperatures by compression alone. Phase transitions of this type may be relevant on icy planetary satellites, and there may also be implications for the high-pressure behavior of silica.

  18. Synthesis of new amorphous metallic spin glasses

    DOEpatents

    Haushalter, R.C.

    1985-02-11

    Disclosed are: amorphous metallic precipitates having the formula (M/sub 1/)/sub a/(M/sub 2/)/sub b/ wherein M/sub 1/ is at least one transition metal, M/sub 2/ is at least one main group metal and the integers ''a'' and ''b'' provide stoichiometric balance; the precipitates having a degree of local order characteristic of chemical compounds from the precipitation process and useful electrical and mechanical properties.

  19. Synthesis of new amorphous metallic spin glasses

    DOEpatents

    Haushalter, Robert C.

    1988-01-01

    Amorphous metallic precipitates having the formula (M.sub.1).sub.a (M.sub.2).sub.b wherein M.sub.1 is at least one transition metal, M.sub.2 is at least one main group metal and the integers "a" and "b" provide stoichiometric balance; the precipitates having a degree of local order characteristic of chemical compounds from the precipitation process and useful electrical and mechanical properties.

  20. Synthesis of new amorphous metallic spin glasses

    DOEpatents

    Haushalter, Robert C.

    1986-01-01

    Amorphous metallic precipitates having the formula (M.sub.1).sub.a (M.sub.2).sub.b wherein M.sub.1 is at least one transition metal, M.sub.2 is at least one main group metal and the integers "a" and "b" provide stoichiometric balance; the precipitates having a degree of local order characteristic of chemical compounds from the precipitation process and useful electrical and mechanical properties.

  1. Magnetic and magnetoelastic properties of amorphous ribbons

    SciTech Connect

    Chiriac, H.; Ciobotaru, I.; Mohorianu, S.

    1994-03-01

    A phenomenological model for the magnetic and magnetoelastic behavior of the field-annealed magnetostrictive ribbon is proposed. The basic hypothesis is that the magnetic domain coupling energy due to the inhomogeneity inherent to amorphous state is dependent on the reduced magnetization. The model takes into account the anisotropy energy, Zeeman energy, magnetoelastic energy and magnetic domain coupling energy. The magnetization, engineering magnetostriction and Young`s modulus are derived as continuous functions of the applied magnetic field and stress.

  2. Design Requirements for Amorphous Piezoelectric Polymers

    NASA Technical Reports Server (NTRS)

    Ounaies, Z.; Young, J. A.; Harrison, J. S.

    1999-01-01

    An overview of the piezoelectric activity in amorphous piezoelectric polymers is presented. The criteria required to render a polymer piezoelectric are discussed. Although piezoelectricity is a coupling between mechanical and electrical properties, most research has concentrated on the electrical properties of potentially piezoelectric polymers. In this work, we present comparative mechanical data as a function of temperature and offer a summary of polarization and electromechanical properties for each of the polymers considered.

  3. Ultrathin amorphous coatings on lunar dust grains.

    PubMed

    Bibring, J P; Duraud, J P; Durrieu, L; Jouret, C; Maurette, M; Meunier, R

    1972-02-18

    UItrathin amorphous coatings have been observed by high-voltage electron microscopy on micrometer-sized dust grains from the Apollo 11, Apollo 12, Apollo 14, and Luna 16 missions. Calibration experiments show that these coatings result from an "ancient" implantation of solar wind ions in the grains. This phenomenon has interdisciplinary applications concerning the past activity of the sun, the lunar albedo, the ancient lunar atmosphere and magnetic field, the carbon content of lunar soils, and lunar dynamic processes.

  4. Seismic fragility analysis of buried steel piping at P, L, and K reactors

    SciTech Connect

    Wingo, H.E.

    1989-10-01

    Analysis of seismic strength of buried cooling water piping in reactor areas is necessary to evaluate the risk of reactor operation because seismic events could damage these buried pipes and cause loss of coolant accidents. This report documents analysis of the ability of this piping to withstand the combined effects of the propagation of seismic waves, the possibility that the piping may not behave in a completely ductile fashion, and the distortions caused by relative displacements of structures connected to the piping.

  5. Diagenesis of shallowly buried cratonic sandstones, southwest Sinai, Egypt

    NASA Astrophysics Data System (ADS)

    Salem, Alaa M. K.; Abdel-Wahab, Antar; McBride, Earle F.

    1998-08-01

    In spite of their age, quartzose and feldspathic Lower Carboniferous sandstones deposited on the Arabian shield in western Sinai remain friable and porous (average of 19%, maximum of 25%) except for strongly cemented ferricretes and silcretes. These fluvial and shallow-marine sandstones were not buried more than 1.5 km until Late Cretaceous and younger time, when the deepest rocks reached 2.5 km. Owing to shallow burial depths and episodic exposure, meteoric water dominated the pore system for most of geologic time: iron oxides had multiple diagenetic stages and yield Carboniferous and Late Cretaceous paleomagnetic signatures, and oxygen isotopic data for authigenic quartz, sparry calcite, and kaolinite yield meteoric signatures. The most significant diagenetic changes were: (1) cementation by iron oxide that locally reaches 40% in groundwater ferricretes; (2) reduction in porosity to 19% from an assumed original porosity 45% (19% porosity was lost by compaction and 7% by cementation); (3) generation of diagenetic quartzarenites by the loss of 7% detrital feldspar by kaolinization and dissolution; and (4) development of three thin mature silcretes apparently by thermal groundwaters. Some outcrop samples have halite and gypsum cements of young but uncertain origin: recycled from topographically higher younger rocks or from aerosols? Mature silcretes are strongly cemented by microcrystalline quartz, multiply zoned syntaxial quartz, and, originally, minor opal. Quartz overgrowths in most sandstones average only 2.2%, but display a variety of textures and in places overprint isopachous opal (now dissolved) grain coats. These features have more in common with incipient silcrete cement than normal burial quartz cement. Most silica was imported in groundwater.

  6. Review of Concrete Biodeterioration in Relation to Buried Nuclear Waste

    SciTech Connect

    Turick, C; Berry, C.

    2012-10-15

    Long-term storage of low level radioactive material in below ground concrete disposal units (DUs) (Saltstone Disposal Facility) is a means of depositing wastes generated from nuclear operations of the U.S. Department of Energy. Based on the currently modeled degradation mechanisms, possible microbial induced effects on the structural integrity of buried low level wastes must be addressed. Previous international efforts related to microbial impacts on concrete structures that house low level radioactive waste showed that microbial activity can play a significant role in the process of concrete degradation and ultimately structural deterioration. This literature review examines the recent research in this field and is focused on specific parameters that are applicable to modeling and prediction of the fate of concrete vaults housing stored wastes and the wastes themselves. Rates of concrete biodegradation vary with the environmental conditions, illustrating a need to understand the bioavailability of key compounds involved in microbial activity. Specific parameters require pH and osmotic pressure to be within a certain range to allow for microbial growth as well as the availability and abundance of energy sources like components involved in sulfur, iron and nitrogen oxidation. Carbon flow and availability are also factors to consider in predicting concrete biodegradation. The results of this review suggest that microbial activity in Saltstone, (grouted low level radioactive waste) is unlikely due to very high pH and osmotic pressure. Biodegradation of the concrete vaults housing the radioactive waste however, is a possibility. The rate and degree of concrete biodegradation is dependent on numerous physical, chemical and biological parameters. Results from this review point to parameters to focus on for modeling activities and also, possible options for mitigation that would minimize concrete biodegradation. In addition, key chemical components that drive microbial

  7. FOREWORD: Special section on electromagnetic characterization of buried obstacles

    NASA Astrophysics Data System (ADS)

    Lesselier, Dominique; Chew, Weng Cho

    2004-12-01

    This Inverse Problems special section on electromagnetic characterization of buried obstacles contains a selection of 14 invited papers, involving 41 authors and 19 research groups worldwide. (Though this section consists of invited papers, the standard refereeing procedures of Inverse Problems have been rigorously observed.) We do not claim to have reached all the high-level researchers in the field, but we believe that we have made a fair attempt. As illustrated by the variety of contributions included, the aim of this special section is to address theoretical and practical inversion problems (and the solutions thereof) that arise in the field of electromagnetic characterization of obstacles (artificial or natural) buried on the Earth or in planetary subsoil. Civil and military engineering, archaeological and environmental issues are typically among those within the scope of the investigation. An example is the characterization of a single (or multiple) obstacle(s) located near the interface or at shallow depths via electromagnetic means operating within relevant frequency bands. However, we also welcomed novel and thought-provoking investigations, even though their direct application to the real world, or even to laboratory-controlled settings, may still be far off. Within this general mathematical and applied framework, the submitted papers focused on a combination of theoretical, computational and experimental developments. They either reviewed the most recent advances in a particular area of research or were an original and specialized contribution. Let us now take the opportunity to remind the readers that this special section harks back (in addition to sharing some common contributors) to two special sections already published in the journal which possessed the same flavour of wave-field inversion and its many applications. They were `Electromagnetic imaging and inversion of the Earth's subsurface', which was published in October 2000 (volume 16, issue 5

  8. Computer model of tetrahedral amorphous diamond

    NASA Astrophysics Data System (ADS)

    Djordjević, B. R.; Thorpe, M. F.; Wooten, F.

    1995-08-01

    We computer generate a model of amorphous diamond using the Wooten-Weaire method, with fourfold coordination everywhere. We investigate two models: one where four-membered rings are allowed and the other where the four-membered rings are forbidden; each model consisting of 4096 atoms. Starting from the perfect diamond crystalline structure, we first randomize the structure by introducing disorder through random bond switches at a sufficiently high temperature. Subsequently, the temperature is reduced in stages, and the topological and geometrical relaxation of the structure takes place using the Keating potential. After a long annealing process, a random network of comparatively low energy is obtained. We calculate the pair distribution function, mean bond angle, rms angular deviation, rms bond length, rms bond-length deviation, and ring statistics for the final relaxed structures. We minimize the total strain energy by adjusting the density of the sample. We compare our results with similar computer-generated models for amorphous silicon, and with experimental measurement of the structure factor for (predominantly tetrahedral) amorphous carbon.

  9. Interactions of hydrogen with amorphous hafnium oxide

    NASA Astrophysics Data System (ADS)

    Kaviani, Moloud; Afanas'ev, Valeri V.; Shluger, Alexander L.

    2017-02-01

    We used density functional theory (DFT) calculations to study the interaction of hydrogen with amorphous hafnia (a -HfO2 ) using a hybrid exchange-correlation functional. Injection of atomic hydrogen, its diffusion towards electrodes, and ionization can be seen as key processes underlying charge instability of high-permittivity amorphous hafnia layers in many applications. Hydrogen in many wide band gap crystalline oxides exhibits negative-U behavior (+1 and -1 charged states are thermodynamically more stable than the neutral state) . Our results show that in a -HfO2 hydrogen is also negative-U, with charged states being the most thermodynamically stable at all Fermi level positions. However, metastable atomic hydrogen can share an electron with intrinsic electron trapping precursor sites [Phys. Rev. B 94, 020103 (2016)., 10.1103/PhysRevB.94.020103] forming a [etr -+O -H ] center, which is lower in energy on average by about 0.2 eV. These electron trapping sites can affect both the dynamics and thermodynamics of the interaction of hydrogen with a -HfO2 and the electrical behavior of amorphous hafnia films in CMOS devices.

  10. Amorphous molybdenum silicon superconducting thin films

    SciTech Connect

    Bosworth, D. Sahonta, S.-L.; Barber, Z. H.; Hadfield, R. H.

    2015-08-15

    Amorphous superconductors have become attractive candidate materials for superconducting nanowire single-photon detectors due to their ease of growth, homogeneity and competitive superconducting properties. To date the majority of devices have been fabricated using W{sub x}Si{sub 1−x}, though other amorphous superconductors such as molybdenum silicide (Mo{sub x}Si{sub 1−x}) offer increased transition temperature. This study focuses on the properties of MoSi thin films grown by magnetron sputtering. We examine how the composition and growth conditions affect film properties. For 100 nm film thickness, we report that the superconducting transition temperature (Tc) reaches a maximum of 7.6 K at a composition of Mo{sub 83}Si{sub 17}. The transition temperature and amorphous character can be improved by cooling of the substrate during growth which inhibits formation of a crystalline phase. X-ray diffraction and transmission electron microscopy studies confirm the absence of long range order. We observe that for a range of 6 common substrates (silicon, thermally oxidized silicon, R- and C-plane sapphire, x-plane lithium niobate and quartz), there is no variation in superconducting transition temperature, making MoSi an excellent candidate material for SNSPDs.

  11. Phase transitions in biogenic amorphous calcium carbonate

    NASA Astrophysics Data System (ADS)

    Gong, Yutao

    Geological calcium carbonate exists in both crystalline phases and amorphous phases. Compared with crystalline calcium carbonate, such as calcite, aragonite and vaterite, the amorphous calcium carbonate (ACC) is unstable. Unlike geological calcium carbonate crystals, crystalline sea urchin spicules (99.9 wt % calcium carbonate and 0.1 wt % proteins) do not present facets. To explain this property, crystal formation via amorphous precursors was proposed in theory. And previous research reported experimental evidence of ACC on the surface of forming sea urchin spicules. By using X-ray absorption near-edge structure (XANES) spectroscopy and photoelectron emission microscopy (PEEM), we studied cross-sections of fresh sea urchin spicules at different stages (36h, 48h and 72h after fertilization) and observed the transition sequence of three mineral phases: hydrated ACC → dehydrated ACC → biogenic calcite. In addition, we unexpectedly found hydrated ACC nanoparticles that are surrounded by biogenic calcite. This observation indicates the dehydration from hydrated ACC to dehydrated ACC is inhibited, resulting in stabilization of hydrated ACC nanoparticles. We thought that the dehydration was inhibited by protein matrix components occluded within the biomineral, and we designed an in vitro assay to test the hypothesis. By utilizing XANES-PEEM, we found that SM50, the most abundant occluded matrix protein in sea urchin spicules, has the function to stabilize hydrated ACC in vitro.

  12. Formation of iron disilicide on amorphous silicon

    NASA Astrophysics Data System (ADS)

    Erlesand, U.; Östling, M.; Bodén, K.

    1991-11-01

    Thin films of iron disilicide, β-FeSi 2 were formed on both amorphous silicon and on crystalline silicon. The β-phase is reported to be semiconducting with a direct band-gap of about 0.85-0.89 eV. This phase is known to form via a nucleation-controlled growth process on crystalline silicon and as a consequence a rather rough silicon/silicide interface is usually formed. In order to improve the interface a bilayer structure of amorphous silicon and iron was sequentially deposited on Czochralski <111> silicon in an e-gun evaporation system. Secondary ion mass spectrometry profiling (SIMS) and scanning electron micrographs revealed an improvement of the interface sharpness. Rutherford backscattering spectrometry (RBS) and X-ray diffractiometry showed β-FeSi 2 formation already at 525°C. It was also observed that the silicide growth was diffusion-controlled, similar to what has been reported for example in the formation of NiSi 2 for the reaction of nickel on amorphous silicon. The kinetics of the FeSi 2 formation in the temperature range 525-625°C was studied by RBS and the activation energy was found to be 1.5 ± 0.1 eV.

  13. Multiple cell photoresponsive amorphous alloys and devices

    SciTech Connect

    Ovshinsky, S.R.; Adler, D.

    1990-01-02

    This patent describes an improved photoresponsive tandem multiple solar cell device. The device comprising: at least a first and second superimposed cell of various materials. The first cell being formed of a silicon alloy material. The second cell including an amorphous silicon alloy semiconductor cell body having an active photoresponsive region in which radiation can impinge to produce charge carriers, the amorphous cell body including at least one density of states reducing element. The element being fluorine. The amorphous cell body further including a band gap adjusting element therein at least in the photoresponsive region to enhance the radiation absorption thereof, the adjusting element being germanium: the second cell being a multi-layer body having deposited semiconductor layers of opposite (p and n) conductivity type; and the first cell being formed with the second cell in substantially direct Junction contact therebetween. The first and second cells designed to generate substantially matched currents from each cell from a light source directed through the first cell and into the second cell.

  14. Newtonian Flow in Bulk Amorphous Alloys

    SciTech Connect

    Wadsworth, J.; Nieh, T.G.

    2000-09-27

    Bulk amorphous alloys have many unique properties, e.g., superior strength and hardness, excellent corrosion resistance, reduced sliding friction and improved wear resistance, and easy formability in a viscous state. These properties, and particularly easy formability, are expected to lead to applications in the fields of near-net-shape fabrication of structural components. Whereas large tensile ductility has generally been observed in the supercooled liquid region in metallic glasses, the exact deformation mechanism, and in particular whether such alloys deform by Newtonian viscous flow, remains a controversial issue. In this paper, existing data are analyzed and an interpretation for the apparent controversy is offered. In addition, new results obtained from an amorphous alloy (composition: Zr-10Al-5TI-17.9Cu-14.6Ni, in at. %) are presented. Structural evolution during plastic deformation is particularly characterized. It is suggested that the appearance of non-Newtonian behavior is a result of the concurrent crystallization of the amorphous structure during deformation.

  15. Crystalline-amorphous transition in silicate perovskites

    SciTech Connect

    Hemmati, M.; Chizmeshya, A. |; Wolf, G.H.; Poole, P.H.; Shao, J.; Angell, C.A.

    1995-06-01

    CaSiO{sub 3} and MgSiO{sub 3} perovskites are known to undergo solid-state crystal to amorphous transitions near ambient pressure when decompressed from their high-pressure stability fields. In order to elucidate the mechanistic aspects of this transition we have performed detailed molecular-dynamics simulations and lattice-dynamical calculations on model silicate perovskite systems using empirical rigid-ion pair potentials. In the simulations at low temperatures, the model perovskite systems transform under tension to a low-density glass composed of corner shared chains of tetrahedral silicon. The amorphization is initiated by a thermally activated step involving a soft polar optic mode in the perovskite phase at the Brillouin zone center. Progression of the system along this reaction coordinate triggers, in succession, multiple barrierless modes of instability ultimately producing a catastrophic decohesion of the lattice. An important intermediary along the reaction path is a crystalline phase where silicon is in a five-coordinate site and the alkaline-earth metal atom is in eightfold coordination. At the onset pressure, this transitory phase is itself dynamically unstable to a number of additional vibrational modes, the most relevant being those which result in transformation to a variety of tetrahedral chain silicate motifs. These results support the conjecture that stress-induced amorphization arises from the near simultaneous accessibility of multiple modes of instability in the highly metastable parent crystalline phase.

  16. Shock induced crystallization of amorphous Nickel powders

    NASA Astrophysics Data System (ADS)

    Cherukara, Mathew; Strachan, Alejandro

    2015-06-01

    Recent experimental work has shown the efficacy of amorphous Ni/crystalline Al composites as energetic materials, with flame velocities twice that of a comparable crystalline Ni/crystalline Al system. Of further interest is the recrystallization mechanisms in the pure amorphous Ni powders, both thermally induced and mechanically induced. We present large-scale molecular dynamics simulations of shock-induced recrystallization in loosely packed amorphous Nickel powders. We study the time dependent nucleation and growth processes by holding the shocked samples at the induced pressures and temperatures for extended periods following the passage of the shock (up to 6 ns). We find that the nanostructure of the recrystallized Ni and time scales of recrystallization are dependent on the piston velocity. At low piston velocities, nucleation events are rare, leading to long incubation times and a relatively coarse nanostructure. At higher piston velocities, local variations in temperature due to jetting phenomena and void collapse, give rise to multiple nucleation events on time scales comparable to the passage of the shock wave, leading to the formation of a fine-grained nanostructure. Interestingly, we observe that the nucleation and growth process occurs in two steps, with the first nuclei crystallizing into the BCC structure, before evolving over time into the expected FCC structure. U.S. Defense Threat Reduction Agency, HDTRA1-10-1-0119 (Program Manager Suhithi Peiris).

  17. Characterization of Amorphous and Co-Amorphous Simvastatin Formulations Prepared by Spray Drying.

    PubMed

    Craye, Goedele; Löbmann, Korbinian; Grohganz, Holger; Rades, Thomas; Laitinen, Riikka

    2015-12-03

    In this study, spray drying from aqueous solutions, using the surface-active agent sodium lauryl sulfate (SLS) as a solubilizer, was explored as a production method for co-amorphous simvastatin-lysine (SVS-LYS) at 1:1 molar mixtures, which previously have been observed to form a co-amorphous mixture upon ball milling. In addition, a spray-dried formulation of SVS without LYS was prepared. Energy-dispersive X-ray spectroscopy (EDS) revealed that SLS coated the SVS and SVS-LYS particles upon spray drying. X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) showed that in the spray-dried formulations the remaining crystallinity originated from SLS only. The best dissolution properties and a "spring and parachute" effect were found for SVS spray-dried from a 5% SLS solution without LYS. Despite the presence of at least partially crystalline SLS in the mixtures, all the studied formulations were able to significantly extend the stability of amorphous SVS compared to previous co-amorphous formulations of SVS. The best stability (at least 12 months in dry conditions) was observed when SLS was spray-dried with SVS (and LYS). In conclusion, spray drying of SVS and LYS from aqueous surfactant solutions was able to produce formulations with improved physical stability for amorphous SVS.

  18. Experimental Studies about Transient Characteristics of a Deeply Buried Grounding Electrode and a Grounding Mesh

    NASA Astrophysics Data System (ADS)

    Yamamoto, Kazuo; Yanagawa, Shunichi; Sekioka, Shozo

    When lightning strikes the tower of a cellular phone base station or other such facilities, power and communication equipments in the vicinity of the tower may suffer extensive damages due to the lightning current flowing backward from the grounding system of the tower. The use of a deeply buried grounding electrode has been proposed recently to suppress such back flow current and a potential rise in the vicinity of the tower. The deeply buried grounding electrode is a bare conductor buried deep in the ground that is connected to a lightning rod on the ground by an insulated wire. When lightning strikes the lightning rod, the lightning current is directed to the electrode from which it diffuses to the ground. The deeply buried grounding electrodes have been installed in cellular phone base stations and other such facilities to solve such problems caused by the back flow current and the potential rise. A grounding mesh is usually laid around such base stations as a grounding system for the facilities on the ground. Therefore, it is important to understand the interactions between the deeply buried grounding electrode and the grounding mesh. In this study, experiments on the interactions between a grounding mesh and a deeply buried grounding electrode have been carried out. Additionally, the transient characteristics of the mesh grounding have researched.

  19. Distinct microbial communities associated with buried soils in the Siberian tundra

    NASA Astrophysics Data System (ADS)

    Gittel, Antje; Bárta, Jiří; Kohoutová, Iva; Mikutta, Robert; Owens, Sarah; Gilbert, Jack; Schnecker, Jörg; Wild, Birgit; Hannisdal, Bjarte; Maerz, Joeran; Lashchinskiy, Nikolay; Čapek, Petr; Šantrůčková, Hana; Gentsch, Norman; Shibistova, Olga; Guggenberger, Georg; Richter, Andreas; Torsvik, Vigdis; Schleper, Christa; Urich, Tim

    2014-05-01

    Cryoturbation, the burial of topsoil material into deeper soil horizons by repeated freeze-thaw events, is an important storage mechanism for soil organic matter (SOM) in permafrost-affected soils. Besides abiotic conditions, microbial community structure and the accessibility of SOM to the decomposer community are hypothesized to control SOM decomposition and thus have a crucial role in SOM accumulation in buried soils. We surveyed the microbial community structure in cryoturbated soils from nine soil profiles in the northeastern Siberian tundra using high-throughput sequencing and quantification of bacterial, archaeal and fungal marker genes. We found that bacterial abundances in buried topsoils were as high as in unburied topsoils. In contrast, fungal abundances decreased with depth and were significantly lower in buried than in unburied topsoils resulting in remarkably low fungal to bacterial ratios in buried topsoils. Fungal community profiling revealed an associated decrease in presumably ectomycorrhizal (ECM) fungi. The abiotic conditions (low to subzero temperatures, anoxia) and the reduced abundance of fungi likely provide a niche for bacterial, facultative anaerobic decomposers of SOM such as members of the Actinobacteria, which were found in significantly higher relative abundances in buried than in unburied topsoils. Our study expands the knowledge on the microbial community structure in soils of Northern latitude permafrost regions, and attributes the delayed decomposition of SOM in buried soils to specific microbial taxa, and particularly to a decrease in abundance and activity of ECM fungi, and to the extent to which bacterial decomposers are able to act as their functional substitutes.

  20. Distinct microbial communities associated with buried soils in the Siberian tundra.

    PubMed

    Gittel, Antje; Bárta, Jiří; Kohoutová, Iva; Mikutta, Robert; Owens, Sarah; Gilbert, Jack; Schnecker, Jörg; Wild, Birgit; Hannisdal, Bjarte; Maerz, Joeran; Lashchinskiy, Nikolay; Capek, Petr; Santrůčková, Hana; Gentsch, Norman; Shibistova, Olga; Guggenberger, Georg; Richter, Andreas; Torsvik, Vigdis L; Schleper, Christa; Urich, Tim

    2014-04-01

    Cryoturbation, the burial of topsoil material into deeper soil horizons by repeated freeze-thaw events, is an important storage mechanism for soil organic matter (SOM) in permafrost-affected soils. Besides abiotic conditions, microbial community structure and the accessibility of SOM to the decomposer community are hypothesized to control SOM decomposition and thus have a crucial role in SOM accumulation in buried soils. We surveyed the microbial community structure in cryoturbated soils from nine soil profiles in the northeastern Siberian tundra using high-throughput sequencing and quantification of bacterial, archaeal and fungal marker genes. We found that bacterial abundances in buried topsoils were as high as in unburied topsoils. In contrast, fungal abundances decreased with depth and were significantly lower in buried than in unburied topsoils resulting in remarkably low fungal to bacterial ratios in buried topsoils. Fungal community profiling revealed an associated decrease in presumably ectomycorrhizal (ECM) fungi. The abiotic conditions (low to subzero temperatures, anoxia) and the reduced abundance of fungi likely provide a niche for bacterial, facultative anaerobic decomposers of SOM such as members of the Actinobacteria, which were found in significantly higher relative abundances in buried than in unburied topsoils. Our study expands the knowledge on the microbial community structure in soils of Northern latitude permafrost regions, and attributes the delayed decomposition of SOM in buried soils to specific microbial taxa, and particularly to a decrease in abundance and activity of ECM fungi, and to the extent to which bacterial decomposers are able to act as their functional substitutes.

  1. Differentiating Mild Papilledema and Buried Optic Nerve Head Drusen Using Spectral Domain Optical Coherence Tomography

    PubMed Central

    Kulkarni, Kaushal M.; Pasol, Joshua; Rosa, Potyra R.; Lam, Byron L.

    2013-01-01

    Purpose To evaluate the clinical utility of spectral domain optical coherence tomography (SD-OCT) in differentiating mild papilledema from buried optic nerve head drusen (ONHD). Design Comparative case series. Participants 16 eyes of 9 patients with ultrasound-proven buried ONHD, 12 eyes of 6 patients with less than or equal to Frisén grade 2 papilledema due to idiopathic intracranial hypertension. 2 normal fellow eyes of patients with buried ONHD were included. Methods A raster scan on the optic nerve and retinal nerve fiber layer (RNFL) thickness analysis was performed on each eye using SD-OCT. Eight eyes underwent enhanced depth imaging SD-OCT. Images were assessed qualitatively and quantitatively to identify differentiating features between buried ONHD and papilledema. Five clinicians trained with a tutorial and masked to the underlying diagnosis reviewed the SD-OCT images of each eye independently to determine the diagnosis. Main outcome measures Differences in RNFL thickness in each quadrant between the two groups, and diagnostic accuracy of five independent clinicians based on the SD-OCT images alone. Results We found no statistically significant difference in RNFL thickness between buried ONHD and papilledema in any of the four quadrants. Diagnostic accuracy among the readers was low and ranged from 50–64%. The kappa coefficient of agreement among the readers was 0.35 (95% Confidence interval: 0.19, 0.54). Conclusions SD-OCT is not clinically reliable in differentiating buried ONHD and mild papilledema. PMID:24321144

  2. Cannabidiol reverses the mCPP-induced increase in marble-burying behavior.

    PubMed

    Nardo, Mirella; Casarotto, Plinio C; Gomes, Felipe V; Guimarães, Francisco S

    2014-10-01

    Cannabidiol (CBD), one of the main components of Cannabis sp., presents clinical and preclinical anxiolytic properties. Recent results using the marble-burying test (MBT) suggest that CBD can also induce anticompulsive-like effects. Meta-chloro-phenyl-piperazine (mCPP) is a nonspecific serotonergic agonist (acting mainly at 5HT1A, 5HT2C and 5HT1D receptors) reported to increase symptoms in OCD patients and block the anticompulsive-like effect of serotonin reuptake inhibitors (SRIs) in animal models. The aim of this study was to investigate the interference of CBD on mCPP effects in repetitive burying. Administration of mCPP showed dual effects in the MBT, increasing the number of buried marbles at lower (0.1 mg/kg) while decreasing it at higher doses (1 mg/kg), an effect not related to a general increase in anxiety-like behavior. As found previously, CBD (30 mg/kg) and the positive control fluoxetine (FLX; 10 mg/kg) decreased burying behavior without changing general exploratory activity. A similar effect was found when subeffective doses of CBD (15 mg/kg) and FLX (3 mg/kg) were administered together. These subeffective doses alone were also able to block mCPP-induced repetitive burying. The results, in addition to reinforcing a possible anticompulsive effect of CBD, also suggest that mCPP-induced repetitive burying could be a useful test for the screening of compounds with presumed anticompulsive properties.

  3. A process for ensuring regulatory compliance at the INEL`s buried waste integrated demonstrations

    SciTech Connect

    Cannon, P.G.; Watson, L.R.; Blacker, P.B.

    1993-03-01

    The Buried Waste Integrated Demonstration Program is funded by the Department of Energy Office of Technology Development. The mission of this Integrated Demonstration is to identify, evaluate, and demonstrate a suite of innovative technologies for the remediation of radioactive and hazardous waste buried throughout the DOE complex between 1950 and 1970. The program approach to development of a long-range strategy for improving buried waste remediation capabilities is to combine systems analysis with already identified remediation needs for DOE complex buried waste. The systems analysis effort has produced several configuration options (a top-level block diagram of a cradle-to-grave remediation system) capable of remediating the transuranic-contaminated waste pits and trenches at the Idaho National Engineering Laboratory. Technologies for demonstration are selected using three criteria: (a) the ability to satisfy a specific buried waste need, (b) the ability to satisfy functional and operational requirements defined for functional sub-elements in a configuration option, and (c) performance against Comprehensive Environmental Restoration and Compensation Liability Act selection criteria, such as effectiveness, implementability, and cost. Early demonstrations experienced problems with missed requirements, prompting the Buried Waste Integrated Demonstration Program Office to organize a Corrective Action Team to identify the cause and recommend corrective actions. The result of this team effort is the focus of this paper.

  4. Characterizing Amorphous Silicates in Extraterrestrial Materials

    NASA Astrophysics Data System (ADS)

    Fu, X.; Wang, A.; Krawczynski, M. J.

    2015-12-01

    Amorphous silicates are common in extraterrestrial materials. They are seen in the matrix of carbonaceous chondrites as well as in planetary materials. Tagish Lake is one of the most primitive carbonaceous meteorites in which TEM and XRD analyses found evidence for poorly crystalline phyllosilicate-like species; Raman spectra revealed amorphous silicates with variable degree of polymerization and low crystallinity. On Mars, CheMin discovered amorphous phases in all analyzed samples, and poorly crystalline smectite in mudstone samples. These discoveries pose questions on the crystallinity of phyllosilicates found by remote sensing on Mars, which is directly relevant to aqueous alteration during geologic history of Mars. Our goal is to use spectroscopy to better characterize amorphous silicates. We use three approaches: (1) using silicate glasses synthesized with controlled chemistry to study the effects of silicate polymerization and (2) using phyllosilicates synthesized with controlled hydrothermal treatment to study the effect of crystallinity on vibrational spectroscopy, finally (3) to use the developed correlations in above two steps to study amorphous phases in meteorites, and those found in future missions to Mars. In the 1st step, silicate glasses were synthesized from pure oxides in a range of NBO/T ratios (from 0 to 4). Depending on the targeted NBO/T and composition of mixed oxides, temperatures for each experiment fell in a range from 1260 to 1520 °C, run for ~ 4 hrs. The melt was quenched in liquid N2 or water. Homogeneity of glass was checked under optical microscopy. Raman spectra were taken over 100 spots on small chips free of bubbles and crystals. We have observed that accompanying an increase of NBO/T, there is a strengthening and a position shift of the Raman peak near 1000 cm-1 (Si-Onon-bridging stretching mode), and the weakening of broad Raman peaks near 500 cm-1 (ring breathing mode) and 700cm-1 (Si-Obridging-Si mode). We are building the

  5. MCNP Modeling Results for Location of Buried TRU Waste Drums

    NASA Astrophysics Data System (ADS)

    Steinman, D. K.; Schweitzer, J. S.

    2006-05-01

    In the 1960's, fifty-five gallon drums of TRU waste were buried in shallow pits on remote U.S. Government facilities such as the Idaho National Engineering Laboratory (now split into the Idaho National Laboratory and the Idaho Completion Project [ICP]). Subsequently, it was decided to remove the drums and the material that was in them from the burial pits and send the material to the Waste Isolation Pilot Plant in New Mexico. Several technologies have been tried to locate the drums non-intrusively with enough precision to minimize the chance for material to be spread into the environment. One of these technologies is the placement of steel probe holes in the pits into which wireline logging probes can be lowered to measure properties and concentrations of material surrounding the probe holes for evidence of TRU material. There is also a concern that large quantities of volatile organic compounds (VOC) are also present that would contaminate the environment during removal. In 2001, the Idaho National Engineering and Environmental Laboratory (INEEL) built two pulsed neutron wireline logging tools to measure TRU and VOC around the probe holes. The tools are the Prompt Fission Neutron (PFN) and the Pulsed Neutron Gamma (PNG), respectively. They were tested experimentally in surrogate test holes in 2003. The work reported here estimates the performance of the tools using Monte-Carlo modelling prior to field deployment. A MCNP model was constructed by INEEL personnel. It was modified by the authors to assess the ability of the tools to predict quantitatively the position and concentration of TRU and VOC materials disposed around the probe holes. The model was used to simulate the tools scanning the probe holes vertically in five centimetre increments. A drum was included in the model that could be placed near the probe hole and at other locations out to forty-five centimetres from the probe-hole in five centimetre increments. Scans were performed with no chlorine in the

  6. Reconstruction of buried objects embedded in circular opaque structures

    NASA Astrophysics Data System (ADS)

    Persico, Raffaele; Gennarelli, Gianluca; Soldovieri, Francesco

    2014-05-01

    This contribution deals with the ground penetrating radar imaging of targets embedded in a visually opaque circular structure. The problem has practical relevance in civil engineering and archeological prospections, where structures of interest such as columns or pillars may have to be inspected in non-invasive way in order to detect the possible presence of anomalies (e.g. cracks, water infiltrations, and so on). In this framework, we investigate the possibility to inspect the circular region of interest thanks to a radar system composed by two antennas that are in contact with the structure and rotate simultaneously around it in order to illuminate and measure the field scattered by buried objects from multiple directions. Two different measurement strategies are examined. The first one is the multimonostatic configuration where the backscattered signal is collected by the transmitting antenna itself, as it moves along the circular observation line. The second acquisition strategy is the multibistatic one, with the transmitting and receiving antennas shifted by a constant angular offset of ninety degrees as they move around the column. From the mathematical viewpoint, the imaging problem is formulated as a linear inverse scattering one holding under Born approximation [1]. Furthermore, the Green's function of a homogeneous medium [2] is used to simplify the evaluation of the kernel of the integral equation. The inverse problem is then solved via the Truncated Singular Value Decomposition algorithm [3] in order to obtain a regularized solution. Tomographic reconstructions based on full-wave synthetic data generated by the Finite Difference Time Domain code GPRmax2D [4] are shown to assess the effectiveness of the reconstruction process. REFERENCES [1] W. C. Chew, Waves and fields in inhomogeneous media, IEEE Press, 1995. [2] R. F. Harrington, Time harmonic electromagnetic waves, McGraw-Hill, New York, USA, 1961. [3] M. Bertero and P. Boccacci, Introduction to

  7. Formation of amorphous silicon by light ion damage

    SciTech Connect

    Shih, Y.C.

    1985-12-01

    Amorphization by implantation of boron ions (which is the lightest element generally used in I.C. fabrication processes) has been systematically studied for various temperatures, various voltages and various dose rates. Based on theoretical considerations and experimental results, a new amorphization model for light and intermediate mass ion damage is proposed consisting of two stages. The role of interstitial type point defects or clusters in amorphization is emphasized. Due to the higher mobility of interstitials out-diffusion to the surface particularly during amorphization with low energy can be significant. From a review of the idealized amorphous structure, diinterstitial-divacancy pairs are suggested to be the embryos of amorphous zones formed during room temperature implantation. The stacking fault loops found in specimens implanted with boron at room temperature are considered to be the origin of secondary defects formed during annealing.

  8. Martian Buried Basins and Implications for Characteristics of the Burial Layer and Underlying Surface

    NASA Technical Reports Server (NTRS)

    Sarid, A. R.; Frey, H. V.; Roark, J. H.

    2003-01-01

    Deciphering the cratering record on Mars has been challenging because it may reflect the changes in both the population of impactors and in the resurfacing processes on Mars. However, it is possible to determine the breadth of impactors captured in the cratering record. Extensive areas of resurfacing are of particular interest because they likely contain material from various ages in Martian history. By deducing the impact populations in both surface and underlying layers of terrain, it is possible to determine the age of the layers and constrain theories on the development of the Martian surface. However, to do so requires a method of seeing impact features which are no longer visible. Topographic data of Mars, taken by the Mars Orbiter Laser Altimeter (MOLA), has revealed impact features buried by resurfacing processes. These features are often indistinguishable on Viking images of the Martian surface. In this study, gridded MOLA data was analyzed in order to locate buried impact features, also called buried basins, in Syria, Solis, and Sinai Planum just south of Valles Marineris. The population statistics of buried features can be compared to those of visible features in order to determine the age of the underlying material and characteristics of the surface cover. Specifically, if the buried population in the Hesperian terrain is similar to the population of visible features in the Noachian, it would suggest that the underlying terrain is Noachian in age. The buried craters can then be compared to visible Noachian craters to reveal the amount of deterioration of the buried features. These comparisons allow us to explore the morphology of the terrain in the Hesperian region to determine if topographic variations are due to differences in the thickness of the overlying material or are a characteristic of the underlying terrain.

  9. Modelling the buried human body environment in upland climes using three contrasting field sites.

    PubMed

    Wilson, Andrew S; Janaway, Robert C; Holland, Andrew D; Dodson, Hilary I; Baran, Eve; Pollard, A Mark; Tobin, Desmond J

    2007-06-14

    Despite an increasing literature on the decomposition of human remains, whether buried or exposed, it is important to recognise the role of specific microenvironments which can either trigger or delay the rate of decomposition. Recent casework in Northern England involving buried and partially buried human remains has demonstrated a need for a more detailed understanding of the effect of contrasting site conditions on cadaver decomposition and on the microenvironment created within the grave itself. Pigs (Sus scrofa) were used as body analogues in three inter-related taphonomy experiments to examine differential decomposition of buried human remains. They were buried at three contrasting field sites (pasture, moorland, and deciduous woodland) within a 15 km radius of the University of Bradford, West Yorkshire, UK. Changes to the buried body and the effect of these changes on hair and associated death-scene textile materials were monitored as was the microenvironment of the grave. At recovery, 6, 12 and 24 months post-burial, the extent of soft tissue decomposition was recorded and samples of fat and soil were collected for gas chromatography mass spectrometry (GCMS) analysis. The results of these studies demonstrated that (1) soil conditions at these three burial sites has a marked effect on the condition of the buried body but even within a single site variation can occur; (2) the process of soft tissue decomposition modifies the localised burial microenvironment in terms of microbiological load, pH, moisture and changes in redox status. These observations have widespread application for the investigation of clandestine burial and time since deposition, and in understanding changes within the burial microenvironment that may impact on biomaterials such as hair and other associated death scene materials.

  10. Polyamorphous transition in amorphous fullerites C{sub 70}

    SciTech Connect

    Borisova, P. A.; Agafonov, S. S.; Glazkov, V. P.; D'yakonova, N. P.; Somenkov, V. A.

    2011-12-15

    Samples of amorphous fullerites C{sub 70} have been obtained by mechanical activation (grinding in a ball mill). The structure of the samples has been investigated by neutron and X-ray diffraction. The high-temperature (up to 1200 Degree-Sign C) annealing of amorphous fullerites revealed a polyamorphous transition from molecular to atomic glass, which is accompanied by the disappearance of fullerene halos at small scattering angles. Possible structural versions of the high-temperature amorphous phase are discussed.

  11. Switching in coplanar amorphous hydrogenated silicon devices

    NASA Astrophysics Data System (ADS)

    Avila, A.; Asomoza, R.

    2000-01-01

    Switching has been observed in a wide variety of materials and devices. Hydrogenated amorphous silicon has become one of the most important cases because of interest in neural network applications. Although there are many reports regarding this phenomenon, not all of the physical processes involved are still determined precisely. Therefore, some more experimental information is needed in order to achieve this task. Much of the behavior of the devices has been ascribed to the existence of a filamentary region which is produced after the first switching process, called forming. We observed this filamentary region in its full extension by producing forming in amorphous silicon devices with coplanar metallic contacts placed near each other (˜5 μm). The I-V characteristics, filament optical and atomic force microscopy images and chemical etching led us to correlate changes in resistance to metal inclusion into the amorphous film. There are two stages: the first is related to contact stabilization, the second to metal transport into the film bulk. Optical images show a permanent filamentary region after forming. AFM images of these filaments showed that they are formed essentially by material accumulation between the contacts. This material tends to get some atomic arrangement, becoming a polycrystalline solid. If the device was led to breakdown, such accumulation becomes either a hillock or a thin conducting channel connecting both contacts. In the case of a switching filament, the accumulation tends to be a chain of smaller hillocks along the conduction path. Metal from the contacts remains in the conduction path after forming and chemical etching indicated that it is placed near the path core. Before forming, a tunneling transport process can be ascribed to the non-ohmic behavior of the samples during the first stage of metallic inclusion.

  12. Novel As-doped, As and N-codoped carbon nanotubes as highly active and durable electrocatalysts for O2 reduction in alkaline medium

    NASA Astrophysics Data System (ADS)

    Liu, Ziwu; Li, Meng; Wang, Fang; Wang, Quan-De

    2016-02-01

    To develop more efficient metal-free cathode electrocatalysts for fuel cells, novel arsenic (As)-doped, As and N-codoped carbon nanotubes are synthesized by chemical vapor deposition in this work. The as-prepared As-containing carbon nanotubes exhibit significantly enhanced activity and long-term durability for the oxygen reduction reaction (ORR) in alkaline medium, indicating that the doping of As or codoping As with other heteroatoms into carbon matrix could improve the ORR activity of carbon materials due to the changes in electronic and physical properties of carbon nanotubes evidenced by density functional theory calculations. Moreover, As-containing carbon nanotubes also display much better methanol tolerance, showing a good potential application for future fuel cells.

  13. Characterization of As-Doped p-Type ZnO by X-ray Absorption Near-Edge Structure Spectroscopy: Theory

    SciTech Connect

    Limpijumnong, S.; Smith, M. F.; Zhang, S. B.

    2006-01-01

    Vaithianathan et al. [Appl. Phys. Lett. 88, 112103 (2006)] measured x-ray absorption near-edge structure (XANES) of As-doped ZnO and analyzed it as evidence for As{sub o} acceptors. However, upon carrying out first principles calculations, we found that the simulated XANES spectrum for As{sub o} is very different from that observed. Instead, the simulated spectrum for As{sub Zn}-2V{sub Zn} defect complex, which is predicted to be an acceptor [S. Limpijumnong et al., Phys. Rev. Lett. 92, 155504 (2004)], is far more consistent with the XANES data. The combination of our study, with the XANES of Vaithianathan et al. might be, until now, the strongest support for the As{sub Zn}-2V{sub Zn} model.

  14. Recent advances in co-amorphous drug formulations.

    PubMed

    Dengale, Swapnil Jayant; Grohganz, Holger; Rades, Thomas; Löbmann, Korbinian

    2016-05-01

    Co-amorphous drug delivery systems have recently gained considerable interest in the pharmaceutical field because of their potential to improve oral bioavailability of poorly water-soluble drugs through drug dissolution enhancement as a result of the amorphous nature of the material. A co-amorphous system is characterized by the use of only low molecular weight components that are mixed into a homogeneous single-phase co-amorphous blend. The use of only low molecular weight co-formers makes this approach very attractive, as the amount of amorphous stabilizer can be significantly reduced compared with other amorphous stabilization techniques. Because of this, several research groups started to investigate the co-amorphous formulation approach, resulting in an increasing amount of scientific publications over the last few years. This study provides an overview of the co-amorphous field and its recent findings. In particular, we investigate co-amorphous formulations from the viewpoint of solid dispersions, describe their formation and mechanism of stabilization, study their impact on dissolution and in vivo performance and briefly outline the future potentials.

  15. Delivery of poorly soluble compounds by amorphous solid dispersions.

    PubMed

    Lee, Thomas W Y; Boersen, Nathan A; Hui, H W; Chow, S F; Wan, K Y; Chow, Albert H L

    2014-01-01

    Solid state manipulation by amorphous solid dispersion has been the subject of intensive research for decades due to their excellent potential for dissolution and bioavailability enhancement. The present review aims to highlight the latest advancement in this area, with focus on the fundamentals, characterization, formulation development and manufacturing of amorphous solid dispersions as well as the new generation amorphization technologies. Additionally, specific applications of amorphous solid dispersion in the formulation of herbal drugs or bioactive natural products are reviewed to reflect the growing interest in this relatively neglected area.

  16. Irreversible Enthalpic Relaxation of Rigid Amorphous Fraction in Isotactic Polystyrene

    NASA Astrophysics Data System (ADS)

    Xu, Hui; Cebe, Peggy

    2004-03-01

    The crystalline, rigid amorphous, and mobile amorphous fractions in isotactic polystyrene (iPS) were studied using: 1. quasi-isothermal temperature-modulated differential scanning calorimetry (TMDSC) (i.e., with step-wise increase of temperature), and 2. regular TMDSC (i.e., with constant rate of temperature increase). The crystal fraction was determined from wide angle X-ray scattering and endotherm analysis; mobile amorphous fraction was determined from heat capacity measurements at the glass transition. The validity of a three-phase model for iPS (comprising crystals, mobile and rigid amorphous fractions) is confirmed by heat capacity measurements made during quasi-isothermal cold crystallization. At the same time, we prove the rigid amorphous fraction to be established at the crystallization temperature and not during subsequent cooling. The rigid amorphous fraction is thus stable below the crystallization temperature Tc, and relaxes at a temperature Ta, between Tc and the melting point of the lowest melting crystals. Upon relaxing, the rigid amorphous fraction undergoes a phase transition to mobile amorphous fraction. For cold-crystallized iPS the relaxation of the rigid amorphous fraction is found to be an enthalpy involved, non-reversible relaxation occurring before the melting of the crystals.

  17. Thermally induced evolution of hydrogenated amorphous carbon

    NASA Astrophysics Data System (ADS)

    Mangolini, Filippo; Rose, Franck; Hilbert, James; Carpick, Robert W.

    2013-10-01

    The thermally induced structural evolution of hydrogenated amorphous carbon (a-C:H) films was investigated in situ by X-ray photoelectron spectroscopy for annealing temperatures up to 500 °C. A model for the conversion of sp3- to sp2-hybridized carbon in a-C:H vs. temperature and time was developed and applied to determine the ranges of activation energies for the thermally activated processes occurring. The energies are consistent with ordering and clustering of sp2 carbon, scission of sp3 carbon-hydrogen bonds and formation of sp2 carbon, and direct transformation of sp3- to sp2-hybridized carbon.

  18. Caltech Center for Structural and Amorphous Metals

    DTIC Science & Technology

    2005-05-10

    fracture resistance and subcritical-crack growth behavior in BMG’s and their composites. We have shown that hydrogen significantly increases the glass...Science des Materiaux , 2713], 2002 L. Shadowspeaker, M. B. Shah and R. Busch, "On the crystalline equilibrium phases of the Zr5 7 Nb 5 Cu 15 .4Ni12.6 A lI0...Lowhaphandu, L.A. Ludrosky, and J.J. Lewandowski "Fracture Resistance of Zr-Ti-Ni-Cu-Be Bulk Amorphous Alloy",, TMS-AIME Fall Meeting, Cincinnati, OH

  19. Optical multilayers with an amorphous fluoropolymer

    NASA Astrophysics Data System (ADS)

    Chow, Robert; Loomis, Gary E.; Lindsey, Edward F.

    1994-09-01

    Multilayered coatings were made by physical vapor deposition (PVD) of a perfluorinated amorphous polymer, Teflon AF2400, together with other optical materials. A high reflector at 1064 nm was made with ZnS and AF2400. An all-organic 1064-nm reflector was made from AF2400 and polyethylene. Oxide (HfO2, SiO2) compatibility was also tested. Each multilayer system adhered to itself. The multilayers were influenced by coating stress and unintentional temperature rises during PVD deposition.

  20. On the crystallization of amorphous germanium films

    NASA Astrophysics Data System (ADS)

    Edelman, F.; Komem, Y.; Bendayan, M.; Beserman, R.

    1993-06-01

    The incubation time for crystallization of amorphous Ge (a-Ge) films, deposited by e-gun, was studied as a function of temperature between 150 and 500°C by means of both in situ transmission electron microscopy and Raman scattering spectroscopy. The temperature dependence of t0 follows an Arrhenius curve with an activation energy of 2.0 eV for free-sustained a-Ge films. In the case where the a-Ge films were on Si 3N 4 substrate, the activation energy of the incubation process was 1.3 eV.

  1. Continuous synthesis of amorphous carbonated apatites.

    PubMed

    Tadic, D; Peters, F; Epple, M

    2002-06-01

    Amorphous carbonated hydroxyapatite was prepared by rapid mixing of aqueous solutions of a continuous computer-controlled reactor. The variation of the carbonate content in the solid product is possible by adjustment of the ratios of phosphate to carbonate in the initial solution. The principal reaction parameters (temperature, pH, stirrer speed, solution composition and supersaturation) are controlled and monitored. By controlling these processing parameters, a non-stoichiometric hydroxyapatite with fine-tuned crystallinity, morphology, and carbonate content can be reproducibly prepared. The higher solubility under the conditions of osteoclastic resorption was tested in vitro at constant pH (4.4).

  2. Radiation resistance studies of amorphous silicon films

    NASA Technical Reports Server (NTRS)

    Woodyard, James R.; Payson, J. Scott

    1989-01-01

    Hydrogenated amorphous silicon thin films were irradiated with 2.00 MeV helium ions using fluences ranging from 1E11 to 1E15 cm(-2). The films were characterized using photothermal deflection spectroscopy and photoconductivity measurements. The investigations show that the radiation introduces sub-band-gap states 1.35 eV below the conduction band and the states increase supralinearly with fluence. Photoconductivity measurements suggest the density of states above the Fermi energy is not changing drastically with fluence.

  3. Femtosecond laser crystallization of amorphous Ge

    SciTech Connect

    Salihoglu, Omer; Aydinli, Atilla; Kueruem, Ulas; Gul Yaglioglu, H.; Elmali, Ayhan

    2011-06-15

    Ultrafast crystallization of amorphous germanium (a-Ge) in ambient has been studied. Plasma enhanced chemical vapor deposition grown a-Ge was irradiated with single femtosecond laser pulses of various durations with a range of fluences from below melting to above ablation threshold. Extensive use of Raman scattering has been employed to determine post solidification features aided by scanning electron microscopy and atomic force microscopy measurements. Linewidth of the Ge optic phonon at 300 cm{sup -1} as a function of laser fluence provides a signature for the crystallization of a-Ge. Various crystallization regimes including nanostructures in the form of nanospheres have been identified.

  4. Femtosecond laser crystallization of amorphous Ge

    NASA Astrophysics Data System (ADS)

    Salihoglu, Omer; Kürüm, Ulaş; Yaglioglu, H. Gul; Elmali, Ayhan; Aydinli, Atilla

    2011-06-01

    Ultrafast crystallization of amorphous germanium (a-Ge) in ambient has been studied. Plasma enhanced chemical vapor deposition grown a-Ge was irradiated with single femtosecond laser pulses of various durations with a range of fluences from below melting to above ablation threshold. Extensive use of Raman scattering has been employed to determine post solidification features aided by scanning electron microscopy and atomic force microscopy measurements. Linewidth of the Ge optic phonon at 300 cm-1 as a function of laser fluence provides a signature for the crystallization of a-Ge. Various crystallization regimes including nanostructures in the form of nanospheres have been identified.

  5. Chemical elimination of amorphous carbon on amorphous carbon nanotubes and its electrochemical performance

    NASA Astrophysics Data System (ADS)

    He, Xiaojun; Jiang, Li; Fan, Chuangang; Lei, Jiangwei; Zheng, Mingdong

    2007-04-01

    Chemical elimination of amorphous carbon on amorphous carbon nanotubes (ACNTs) was for the first time investigated by different treatment processes. Electrochemical performance of the modified ACNTs/carbon paste electrode (ACNTs/CPE) was measured by cyclic voltammetry. Field emission scanning and transmission electron microscope (STEM) observation reveals that the diameter of ACNTs is in the range of 60-100 nm. The amorphous nature of ACNTs was proved by the result of Raman analysis. FT-IR spectra showed that it might be one of the low-cost ways to eliminate amorphous carbon on the surface of ACNTs to treat ACNTs with HNO 3 in microwave oven. Further oxidation in air would lead to the decrease of electron transfer rate on the ACNTs/CPE because OH groups on the wall of ACNTs were partly eliminated by oxidation in air. The results of cyclic voltammetry showed that ACNTs/CPE treated with HNO 3 in microwave oven has optimal peak in relation to the highest redox peak current.

  6. Analytical model of LDMOS with a single step buried oxide layer

    NASA Astrophysics Data System (ADS)

    Yuan, Song; Duan, Baoxing; Cao, Zhen; Guo, Haijun; Yang, Yintang

    2016-09-01

    In this paper, a two-dimensional analytical model is established for the Single-Step Buried Oxide SOI structure proposed by the authors. Based on the two-dimensional Poisson equation, the analytic expression of the surface electric field and potential distributions for the device is achieved. In the SBOSOI (Single-Step Buried Oxide Silicon On Insulator) structure, the buried oxide layer thickness changes stepwise along the drift region, and the electric field in the oxide layer also varies with the different buried oxide layer thickness. These variations will modulate the surface electric field distribution through the electric field modulation effects, which makes the surface electric field distribution more uniform. As a result, the breakdown voltage of the device is improved by 60% compared with the conventional SOI structure. To verify the accuracy of the analytical model, the device simulation software ISE TCAD is utilized, the analytical values are in good agreement with the simulation results by the simulation software. The results verified the established two-dimensional analytical model for SBOSOI structure is valid, and it also illustrates the breakdown voltage enhancement by the electric field modulation effect sufficiently. The established analytical models will provide the physical and mathematical basis for further analysis of the new power devices with the patterned buried oxide layer.

  7. Kelvin probe characterization of buried graphitic microchannels in single-crystal diamond

    SciTech Connect

    Bernardi, E. Battiato, A.; Olivero, P.; Vittone, E.; Picollo, F.

    2015-01-14

    In this work, we present an investigation by Kelvin Probe Microscopy (KPM) of buried graphitic microchannels fabricated in single-crystal diamond by direct MeV ion microbeam writing. Metal deposition of variable-thickness masks was adopted to implant channels with emerging endpoints and high temperature annealing was performed in order to induce the graphitization of the highly-damaged buried region. When an electrical current was flowing through the biased buried channel, the structure was clearly evidenced by KPM maps of the electrical potential of the surface region overlying the channel at increasing distances from the grounded electrode. The KPM profiling shows regions of opposite contrast located at different distances from the endpoints of the channel. This effect is attributed to the different electrical conduction properties of the surface and of the buried graphitic layer. The model adopted to interpret these KPM maps and profiles proved to be suitable for the electronic characterization of buried conductive channels, providing a non-invasive method to measure the local resistivity with a micrometer resolution. The results demonstrate the potential of the technique as a powerful diagnostic tool to monitor the functionality of all-carbon graphite/diamond devices to be fabricated by MeV ion beam lithography.

  8. Buried free flaps in head and neck reconstruction: higher risk of free flap failure?

    PubMed

    Reiter, M; Harréus, U; Kisser, U; Betz, C S; Baumeister, Ph

    2017-01-01

    Thrombosis of the pedicle is central to free flap failure, and early revision of a compromised flap is the key to successfully salvage a flap. Therefore, the majority of free flaps in reconstructive head and neck surgery are used with the ability to visually examine the flap. Sometimes, due to intra-operative circumstances, it is necessary to use a flap that cannot be monitored externally. These flaps are called buried flaps and have the reputation of being put at risk. The current literature provides only limited data to support or disprove this position. A single institution retrospective review of patient charts between 2007 and 2015 was performed. Flap monitoring was carried out with hand-held Doppler of the pedicle hourly for the first 72 h in all cases. Additional duplex ultrasound was performed in the majority of buried flaps. A total of 437 flaps were included into the study. 37 flaps (7.8 %) were identified to fulfill the criteria of a buried free flap. In total, four patients had complications, three of which required operative reexploration. All interventions were successful, resulting in no flap loss in our series. An accurate operation technique combined with meticulous monitoring protocols supported by duplex ultrasound can result in satisfactory outcome of buried flaps. No enhanced risk of flap loss of buried flaps was found in our cohort.

  9. Role and development of soil parameters for seismic responses of buried lifelines

    SciTech Connect

    Wang, L.R.L.

    1983-01-01

    Buried lifelines, e.g. oil, gas, water and sewer pipelines have been damaged heavily in recent earthquakes such as 1971 San Fernando Earthquake, in U.S.A., 1976 Tangshan Earthquake, in China, and 1978 MiyagiKen-Oki Earthquake, in Japan, among others. Researchers on the seismic performance of these buried lifelines have been initiated in the United States and many other countries. Various analytical models have been proposed. However, only limited experimental investigations are available. The sources of earthquake damage to buried lifelines include landslide, tectonic uplift-subsidence, soil liquefaction, fault displacement and ground shaking (effects of wave propagation). This paper is concerned with the behavior of buried lifeline systems subjected to surface faulting and ground shaking. The role and development of soil parameters that significantly influence the seismic responses are discussed. The scope of this paper is to examine analytically the influence of various soil and soilstructure interaction parameters to the seismic responses of buried pipelines, to report the currently available physical data of these and related parameters for immediate applications, and to describe the experiments to obtain additional information on soil resistant characteristics to longitudinal pipe motions.

  10. Accelerometer measurements of acoustic-to-seismic coupling above buried objects.

    PubMed

    Attenborough, Keith; Qin, Qin; Jefferis, Jonathan; Heald, Gary

    2007-12-01

    The surface velocity of sand inside a large PVC container, induced by the sound pressure from either a large loudspeaker radiating into an inverted cone and pipe or a Bruel and Kjaer point source loudspeaker mounted with its axis vertical, has been measured using accelerometers. Results of white noise and stepped frequency excitation are presented. Without any buried object the mass loading of an accelerometer creates resonances in the spectral ratio of sand surface velocity to incident acoustic pressure, i.e., the acoustic-to-seismic (A/S) admittance spectra. The A/S responses above a buried compliant object are larger and distinctive. The linear A/S admittance spectra in the presence of a buried electronic components box have been studied as a function of burial depth and sand state. The nonlinear responses above the buried box have been studied as a function of depth, sand state, and amplitude. Predictions of a modified one-dimensional lumped parameter model have been found to be consistent with the observed nonlinear responses. Also the modified model has been used to explain features of the A/S responses observed when using an accelerometer without any buried object.

  11. Theoretical and Experimental Characterizations of the IR Technology for the Detection of Low-Metal and Nonmetallic Buried Landmines

    DTIC Science & Technology

    1997-03-01

    two models are P502142.PDF [Page: 12 of 120] UNCLASSIFIED 2 proposed: a general model defining the main components of the buried mine thermodynamic ...temperature at sufficient depth. The first principle addresses the surfaces of soil showing equivalent optical properties (as road sections) and...thermal properties of the soil covering the buried mine compared with the surrounding soils. This second cause for the heat impedance of a buried

  12. GPR investigations in galleries buried inside a karstified limestone formation

    NASA Astrophysics Data System (ADS)

    Rousset, D.; Sénéchal, G.; Gaffet, S.

    2009-04-01

    A large scientific program of geophysical investigations is presently performed inside the Low-Noise Underground Laboratory (Laboratoire Souterrain à Bas Bruit / LSBB, Rustrel, France) which is an decomissioned underground missile control center, buried in a karstified limestone formation. One of the goals of this project is the understanding of the water circulation inside the structure. This experimental site offers a unique opportunity of perfoming measurements within an unweathered limestone massif. The tunnel has been dug in lower cretaceous limestone which is characterized by a low clay content, high electrical resistivity. The dip is around 25 degrees and vertical faults locally affect the structure. The studied zone is located in south-eastern France (Provence) and is characterized by a mediterranean climate with long dry periods and strong, short events of rain. This phenomenon induces large variations of water content within the karstified limestone from dry to saturated conditions. Analysis of the spatial and temporal variations of the water flow in a karstified limestones needs to define the geological context and the adequate geophysical methods. GPR offers a good tradeoff between resolution and ease of use on one hand and investigation depth on the other hand. We present some GPR profiles which have been acquired in April 2008 after a quite long and strong period of rain, inducing a complete water saturation inside the karstified massif. We used several RAMAC shielded antennas from 100 to 500 MHz. The longest profile is around 600 m long, with a 20 cm spacing, running from a raw to a concrete gallery. These data sets are characterized by a very good signal to noise ratio and a signal penetration, up to 18 meters. Signal processing includes very low frequency filtering, amplitude compensation, keeping lateral relative attenuation and ringing suppression. Final sections includes migration and time to depth conversion or depth migration. The estimated

  13. Method and apparatus for increasing resistance of bipolar buried layer integrated circuit devices to single-event upsets

    NASA Technical Reports Server (NTRS)

    Zoutendyk, John A. (Inventor)

    1991-01-01

    Bipolar transistors fabricated in separate buried layers of an integrated circuit chip are electrically isolated with a built-in potential barrier established by doping the buried layer with a polarity opposite doping in the chip substrate. To increase the resistance of the bipolar transistors to single-event upsets due to ionized particle radiation, the substrate is biased relative to the buried layer with an external bias voltage selected to offset the built-in potential just enough (typically between about +0.1 to +0.2 volt) to prevent an accumulation of charge in the buried-layer-substrate junction.

  14. Emergent interparticle interactions in thermal amorphous solids

    NASA Astrophysics Data System (ADS)

    Gendelman, Oleg; Lerner, Edan; Pollack, Yoav G.; Procaccia, Itamar; Rainone, Corrado; Riechers, Birte

    2016-11-01

    Amorphous media at finite temperatures, be them liquids, colloids, or glasses, are made of interacting particles that move chaotically due to thermal energy, continuously colliding and scattering off each other. When the average configuration in these systems relaxes only at long times, one can introduce effective interactions that keep the mean positions in mechanical equilibrium. We introduce a framework to determine the effective force laws that define an effective Hessian that can be employed to discuss stability properties and the density of states of the amorphous system. We exemplify the approach with a thermal glass of hard spheres; these experience zero forces when not in contact and infinite forces when they touch. Close to jamming we recapture the effective interactions that at temperature T depend on the gap h between spheres as T /h [C. Brito and M. Wyart, Europhys. Lett. 76, 149 (2006), 10.1209/epl/i2006-10238-x]. For hard spheres at lower densities or for systems whose binary bare interactions are longer ranged (at any density), the emergent force laws include ternary, quaternary, and generally higher-order many-body terms, leading to a temperature-dependent effective Hessian.

  15. The future of amorphous silicon photovoltaic technology

    SciTech Connect

    Crandall, R; Luft, W

    1995-06-01

    Amorphous silicon modules are commercially available. They are the first truly commercial thin-film photovoltaic (PV) devices. Well-defined production processes over very large areas (>1 m{sup 2}) have been implemented. There are few environmental issues during manufacturing, deployment in the field, or with the eventual disposal of the modules. Manufacturing safety issues are well characterized and controllable. The highest measured initial efficiency to date is 13.7% for a small triple-stacked cell and the highest stabilized module efficiency is 10%. There is a consensus among researchers, that in order to achieve a 15% stabilized efficiency, a triple-junction amorphous silicon structure is required. Fundamental improvements in alloys are needed for higher efficiencies. This is being pursued through the DOE/NREL Thin-Film Partnership Program. Cost reductions through improved manufacturing processes are being pursued under the National Renewable Energy Laboratory/US Department of Energy (NREL/DOE)-sponsored research in manufacturing technology (PVMaT). Much of the work in designing a-Si devices is a result of trying to compensate for the Staebler-Wronski effect. Some new deposition techniques hold promise because they have produced materials with lower stabilized defect densities. However, none has yet produced a high efficiency device and shown it to be more stable than those from standard glow discharge deposited material.

  16. Anisotropic mechanical amorphization drives wear in diamond

    NASA Astrophysics Data System (ADS)

    Pastewka, Lars; Moser, Stefan; Gumbsch, Peter; Moseler, Michael

    2011-01-01

    Diamond is the hardest material on Earth. Nevertheless, polishing diamond is possible with a process that has remained unaltered for centuries and is still used for jewellery and coatings: the diamond is pressed against a rotating disc with embedded diamond grit. When polishing polycrystalline diamond, surface topographies become non-uniform because wear rates depend on crystal orientations. This anisotropy is not fully understood and impedes diamond’s widespread use in applications that require planar polycrystalline films, ranging from cutting tools to confinement fusion. Here, we use molecular dynamics to show that polished diamond undergoes an sp3-sp2 order-disorder transition resulting in an amorphous adlayer with a growth rate that strongly depends on surface orientation and sliding direction, in excellent correlation with experimental wear rates. This anisotropy originates in mechanically steered dissociation of individual crystal bonds. Similarly to other planarization processes, the diamond surface is chemically activated by mechanical means. Final removal of the amorphous interlayer proceeds either mechanically or through etching by ambient oxygen.

  17. Anisotropic mechanical amorphization drives wear in diamond.

    PubMed

    Pastewka, Lars; Moser, Stefan; Gumbsch, Peter; Moseler, Michael

    2011-01-01

    Diamond is the hardest material on Earth. Nevertheless, polishing diamond is possible with a process that has remained unaltered for centuries and is still used for jewellery and coatings: the diamond is pressed against a rotating disc with embedded diamond grit. When polishing polycrystalline diamond, surface topographies become non-uniform because wear rates depend on crystal orientations. This anisotropy is not fully understood and impedes diamond's widespread use in applications that require planar polycrystalline films, ranging from cutting tools to confinement fusion. Here, we use molecular dynamics to show that polished diamond undergoes an sp(3)-sp(2) order-disorder transition resulting in an amorphous adlayer with a growth rate that strongly depends on surface orientation and sliding direction, in excellent correlation with experimental wear rates. This anisotropy originates in mechanically steered dissociation of individual crystal bonds. Similarly to other planarization processes, the diamond surface is chemically activated by mechanical means. Final removal of the amorphous interlayer proceeds either mechanically or through etching by ambient oxygen.

  18. Structural Characteristics of Synthetic Amorphous Calcium Carbonate

    SciTech Connect

    Michel, F. Marc; MacDonald, Jason; Feng, Jian; Phillips, Brian L.; Ehm, Lars; Tarabrella, Cathy; Parise, John B.; Reeder, Richard J.

    2008-08-06

    Amorphous calcium carbonate (ACC) is an important phase involved in calcification by a wide variety of invertebrate organisms and is of technological interest in the development of functional materials. Despite widespread scientific interest in this phase a full characterization of structure is lacking. This is mainly due to its metastability and difficulties in evaluating structure using conventional structure determination methods. Here we present new findings from the application of two techniques, pair distribution function analysis and nuclear magnetic resonance spectroscopy, which provide new insight to structural aspects of synthetic ACC. Several important results have emerged from this study of ACC formed in vitro using two common preparation methods: (1) ACC exhibits no structural coherence over distances > 15 {angstrom} and is truly amorphous; (2) most of the hydrogen in ACC is present as structural H{sub 2}O, about half of which undergoes restricted motion on the millisecond time scale near room temperature; (3) the short- and intermediate-range structure of ACC shows no distinct match to any known structure in the calcium carbonate system; and (4) most of the carbonate in ACC is monodentate making it distinctly different from monohydrocalcite. Although the structure of synthetic ACC is still not fully understood, the results presented provide an important baseline for future experiments evaluating biogenic ACC and samples containing certain additives that may play a role in stabilization of ACC, crystallization kinetics, and final polymorph selection.

  19. Cryoflotation: densities of amorphous and crystalline ices.

    PubMed

    Loerting, Thomas; Bauer, Marion; Kohl, Ingrid; Watschinger, Katrin; Winkel, Katrin; Mayer, Erwin

    2011-12-08

    We present an experimental method aimed at measuring mass densities of solids at ambient pressure. The principle of the method is flotation in a mixture of liquid nitrogen and liquid argon, where the mixing ratio is varied until the solid hovers in the liquid mixture. The temperature of such mixtures is in the range of 77-87 K, and therefore, the main advantage of the method is the possibility of determining densities of solid samples, which are instable above 90 K. The accessible density range (~0.81-1.40 g cm(-3)) is perfectly suitable for the study of crystalline ice polymorphs and amorphous ices. As a benchmark, we here determine densities of crystalline polymorphs (ices I(h), I(c), II, IV, V, VI, IX, and XII) by flotation and compare them with crystallographic densities. The reproducibility of the method is about ±0.005 g cm(-3), and in general, the agreement with crystallographic densities is very good. Furthermore, we show measurements on a range of amorphous ice samples and correlate the density with the d spacing of the first broad halo peak in diffraction experiments. Finally, we discuss the influence of microstructure, in particular voids, on the density for the case of hyperquenched glassy water and cubic ice samples prepared by deposition of micrometer-sized liquid droplets.

  20. CORROSION STUDY OF AMORPHOUS METAL RIBBONS

    SciTech Connect

    Lian, T; Day, S D; Farmer, J C

    2006-07-31

    Corrosion costs the Department of Defense billions of dollars every year, with an immense quantity of material in various structures undergoing corrosion. For example, in addition to fluid and seawater piping, ballast tanks, and propulsions systems, approximately 345 million square feet of structure aboard naval ships and crafts require costly corrosion control measures. The use of advanced corrosion-resistant materials to prevent the continuous degradation of this massive surface area would be extremely beneficial. The potential advantages of amorphous metals have been recognized for some time [Latanison 1985]. Iron-based corrosion-resistant, amorphous-metal coatings under development may prove important for maritime applications [Farmer et al. 2005]. Such materials could also be used to coat the entire outer surface of containers for the transportation and long-term storage of spent nuclear fuel, or to protect welds and heat affected zones, thereby preventing exposure to environments that might cause stress corrosion cracking [Farmer et al. 1991, 2000a, 2000b]. In the future, it may be possible to substitute such high-performance iron-based materials for more-expensive nickel-based alloys, thereby enabling cost savings in a wide variety of industrial applications. It should be noted that thermal-spray ceramic coatings have also been investigated for such applications [Haslam et al. 2005]. This report focuses on the corrosion resistance of iron-based melt-spun amorphous metal ribbons. Melt-Spun ribbon is made by rapid solidification--a stream of molten metal is dropped onto a spinning copper wheel, a process that enables the manufacture of amorphous metals which are unable to be manufactured by conventional cold or hot rolling techniques. The study of melt-spun ribbon allows quick evaluation of amorphous metals corrosion resistance. The melt-spun ribbons included in this study are DAR40, SAM7, and SAM8, SAM1X series, and SAM2X series. The SAM1X series ribbons have

  1. Characterization of the Marquez Dome buried impact crater using gravity and magnetic data

    NASA Technical Reports Server (NTRS)

    Wong, A. M.; Reid, A. M.; Hall, S. A.; Sharpton, V. L.

    1993-01-01

    The buried impact crater, Marquez Dome, located in Leon County in east central Texas, is an approximately 15 km diameter structure whose central uplift is now partially exposed due to headward erosion of the post-impact cover. The central uplift is approximately 3 km in diameter and the rocks within it have been uplifted more than 1200 m above their regional level. The crater rim remains buried and previous attempts to determine its location have had to rely on seismic reflection data and geologic well logs. These attempts have been somewhat successful in mapping the extent of the disturbed zone around Marquez Dome, but more limited in their ability to image the shallow buried rim. In an attempt to define accurately the whole Marquez Dome structure and assist in the selection of drilling sites, a geophysical investigation involving gravity and magnetic data over the central uplift and the surrounding area has been undertaken.

  2. A "watch window" technique for monitoring buried free jejunum flaps during circumferential pharyngolaryngectomy reconstruction.

    PubMed

    Li, Quan; Zhang, Xin-Rui; Liu, Xue-Kui; Zhang, Zhi-Gang; Liu, Wei-Wei; Li, Hao; Guo, Zhu-Ming

    2012-07-01

    The free jejunum flap approach is the optimal option for circumferential pharyngolaryngectomy reconstruction. In this study, we designed a "watch window" for monitoring buried free jejunum flaps, thereby allowing us to assess graft viability. From 2007 to 2011, 14 patients with hypopharyngeal cancer underwent circumferential pharyngolaryngectomy that was reconstructed using a free jejunum flap at the Sun Yat-sen University Cancer Centre. During the closing of the neck incision, a "watch window" was designed for postoperative monitoring. Two patients experienced thrombosis of the pedicle. One was detected early and successfully rescued by removal of the thrombosis, the other one managed with a second free jejunum flap. The success rate of the buried flaps was 92.9%. No pharyngocutaneous fistulas or strictures occurred. All patients eventually resumed oral feeding and swallowing. The "watch window" technique for monitoring buried free jejunum flaps is simple, reliable and useful for finding vascular problems. Level of evidence Case series.

  3. Characterization of the Marquez Dome buried impact crater using gravity and magnetic data

    NASA Astrophysics Data System (ADS)

    Wong, A. M.; Reid, A. M.; Hall, S. A.; Sharpton, V. L.

    1993-03-01

    The buried impact crater, Marquez Dome, located in Leon County in east central Texas, is an approximately 15 km diameter structure whose central uplift is now partially exposed due to headward erosion of the post-impact cover. The central uplift is approximately 3 km in diameter and the rocks within it have been uplifted more than 1200 m above their regional level. The crater rim remains buried and previous attempts to determine its location have had to rely on seismic reflection data and geologic well logs. These attempts have been somewhat successful in mapping the extent of the disturbed zone around Marquez Dome, but more limited in their ability to image the shallow buried rim. In an attempt to define accurately the whole Marquez Dome structure and assist in the selection of drilling sites, a geophysical investigation involving gravity and magnetic data over the central uplift and the surrounding area has been undertaken.

  4. Atomic friction at exposed and buried graphite step edges: Experiments and simulations

    SciTech Connect

    Ye, Zhijiang; Martini, Ashlie

    2015-06-08

    The surfaces of layered materials such as graphite exhibit step edges that affect friction. Step edges can be exposed, where the step occurs at the outmost layer, or buried, where the step is underneath another layer of material. Here, we study friction at exposed and buried step edges on graphite using an atomic force microscope (AFM) and complementary molecular dynamics simulations of the AFM tip apex. Exposed and buried steps exhibit distinct friction behavior, and the friction on either step is affected by the direction of sliding, i.e., moving up or down the step, and the bluntness of the tip. These trends are analyzing in terms of the trajectory of the AFM tip as it moves over the step, which is a convolution of the topography of the surface and the tip shape.

  5. Numerical Modeling for Impact-resistant Pipes Buried at Shallow Depth

    NASA Astrophysics Data System (ADS)

    Wang, Ching-Jong; Hsu, Jung-Fu

    2010-05-01

    The plastic pipes buried at shallow depth are popular for underground telecommunication lines. To assess their impact-worthiness under loads from heavy traffics, the study establishes a numerical model to correlate with field data. Field impact tests were carried out where a 50-kg mass free-falling at 2.2 m height was dropped onto the soil backfill directly above a buried pipe. A contact-impact model incorporating finite elements of disjoined material regions is developed to simulate the phenomena of mass-soil-pipe interaction and soil dent. Plastic soil deformations are accounted for. Also implemented is a new erosion scheme for dealing with numerical instability caused by crumpled elements during heavy impact. Reasonable agreements can be observed between the analyzed and measured soil dent. This model is versatile in making design evaluations for buried pipes to withstand impact loads. It has potential applications to cemented soil fills and blast loads.

  6. Electron Temperature Measurement of Buried Layer Targets Using Time Resolved K-shell Spectroscopy

    NASA Astrophysics Data System (ADS)

    Marley, Edward; Foord, M. E.; Shepherd, R.; Beiersdorfer, P.; Brown, G.; Chen, H.; Emig, J.; Schneider, M.; Widmann, K.; Scott, H.; London, R.; Martin, M.; Wilson, B.; Iglesias, C.; Mauche, C.; Whitley, H.; Nilsen, J.; Hoarty, D.; James, S.; Brown, C. R. D.; Hill, M.; Allan, P.; Hobbs, L.

    2016-10-01

    Short pulse laser-heated buried layer experiments have been performed with the goal of creating plasmas with mass densities >= 1 g/cm3 and electron temperatures >= 500 eV. The buried layer geometry has the advantage of rapid energy deposition before significant hydrodynamic expansion occurs. For brief periods (< 40 ps) this provides a low gradient, high density platform for studying emission characteristics under extreme plasma conditions. A study of plasma conditions achievable using the Orion laser facility has been performed. Time resolved K-shell spectroscopy was used to determine the temperature evolution of buried layer aluminum foil targets. The measured evolution is compared to a 2-D PIC simulation done using LSP, which shows late time heating from the non-thermal electron population. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  7. A one dimensional numerical approach for computing the eigenmodes of elastic waves in buried pipelines

    NASA Astrophysics Data System (ADS)

    Duan, Wenbo; Kirby, Ray; Mudge, Peter; Gan, Tat-Hean

    2016-12-01

    Ultrasonic guided waves are often used in the detection of defects in oil and gas pipelines. It is common for these pipelines to be buried underground and this may restrict the length of the pipe that can be successfully tested. This is because acoustic energy travelling along the pipe walls may radiate out into the surrounding medium. Accordingly, it is important to develop a better understanding of the way in which elastic waves propagate along the walls of buried pipes, and so in this article a numerical model is developed that is suitable for computing the eigenmodes for uncoated and coated buried pipes. This is achieved by combining a one dimensional eigensolution based on the semi-analytic finite element (SAFE) method, with a perfectly matched layer (PML) for the infinite medium surrounding the pipe. This article also explores an alternative exponential complex coordinate stretching function for the PML in order to improve solution convergence. It is shown for buried pipelines that accurate solutions may be obtained over the entire frequency range typically used in long range ultrasonic testing (LRUT) using a PML layer with a thickness equal to the pipe wall thickness. This delivers a fast and computationally efficient method and it is shown for pipes buried in sand or soil that relevant eigenmodes can be computed and sorted in less than one second using relatively modest computer hardware. The method is also used to find eigenmodes for a buried pipe coated with the viscoelastic material bitumen. It was recently observed in the literature that a viscoelastic coating may effectively isolate particular eigenmodes so that energy does not radiate from these modes into the surrounding [elastic] medium. A similar effect is also observed in this article and it is shown that this occurs even for a relatively thin layer of bitumen, and when the shear impedance of the coating material is larger than that of the surrounding medium.

  8. Physical Modelling on Detecting Buried Object Using Electrical Resistivity Imaging (ERI)

    NASA Astrophysics Data System (ADS)

    Hazreek, Z. A. M.; Nizam, Z. M.; Azhar, A. T. S.; Aziman, M.; Shaylinda, M. Z. N.

    2016-07-01

    This study focused on the evaluation of electrical resistivity method (ERM) for buried object detection and its relationship due to the different stiffness of material. In the past, the conventional method to detect the buried structure was face some limitation due to the time and cost. For example, previous approach related to the trial and error excavation has always expose to some risky outcome due to the uncertainties of the buried object location. Hence, this study introduced an alternative technique with particular reference to resistivity method to detect and evaluate the buried object with different strength of stiffness. The experiment was performed based on field miniature model (small scale study) using soil trial embankment made by lateritic soil and various concrete cube strengths (grade 20, 25 and 30) representing buried object with different conditions. 2D electrical resistivity test (electrical resistivity imaging) was perform using ABEM Terrameter SAS4000 during the data acquisition while the raw data was process using RES2DINV software. It was found that the electrical resistivity method was able to detect the buried concrete structures targeted based on the contrast of the electrical resistivity image produced. Moreover, three different strength of concrete cube were able to be differentiated based on the electrical resistivity values (ERV) obtained. This study found that the ERV of concrete cube for grade 20, 25 and 30 were 170 Ωm, 227 Ωm and 503 Ωm, respectively. Hence, this study shows that the ERV has a strong relationship with different stiffness of material thus applicable to be a useful alternative tool in underground structure detection.

  9. Distinct microbial communities associated with buried soils in the Siberian tundra

    PubMed Central

    Gittel, Antje; Bárta, Jiří; Kohoutová, Iva; Mikutta, Robert; Owens, Sarah; Gilbert, Jack; Schnecker, Jörg; Wild, Birgit; Hannisdal, Bjarte; Maerz, Joeran; Lashchinskiy, Nikolay; Čapek, Petr; Šantrůčková, Hana; Gentsch, Norman; Shibistova, Olga; Guggenberger, Georg; Richter, Andreas; Torsvik, Vigdis L; Schleper, Christa; Urich, Tim

    2014-01-01

    Cryoturbation, the burial of topsoil material into deeper soil horizons by repeated freeze–thaw events, is an important storage mechanism for soil organic matter (SOM) in permafrost-affected soils. Besides abiotic conditions, microbial community structure and the accessibility of SOM to the decomposer community are hypothesized to control SOM decomposition and thus have a crucial role in SOM accumulation in buried soils. We surveyed the microbial community structure in cryoturbated soils from nine soil profiles in the northeastern Siberian tundra using high-throughput sequencing and quantification of bacterial, archaeal and fungal marker genes. We found that bacterial abundances in buried topsoils were as high as in unburied topsoils. In contrast, fungal abundances decreased with depth and were significantly lower in buried than in unburied topsoils resulting in remarkably low fungal to bacterial ratios in buried topsoils. Fungal community profiling revealed an associated decrease in presumably ectomycorrhizal (ECM) fungi. The abiotic conditions (low to subzero temperatures, anoxia) and the reduced abundance of fungi likely provide a niche for bacterial, facultative anaerobic decomposers of SOM such as members of the Actinobacteria, which were found in significantly higher relative abundances in buried than in unburied topsoils. Our study expands the knowledge on the microbial community structure in soils of Northern latitude permafrost regions, and attributes the delayed decomposition of SOM in buried soils to specific microbial taxa, and particularly to a decrease in abundance and activity of ECM fungi, and to the extent to which bacterial decomposers are able to act as their functional substitutes. PMID:24335828

  10. Endurance Tests Of Amorphous-Silicon Photovoltaic Modules

    NASA Technical Reports Server (NTRS)

    Ross, Ronald G., Jr.; Sugimura, Russell S.

    1989-01-01

    Failure mechanisms in high-power service studied. Report discusses factors affecting endurance of amorphous-silicon solar cells. Based on field tests and accelerated aging of photovoltaic modules. Concludes that aggressive research needed if amorphous-silicon modules to attain 10-year life - value U.S. Department of Energy established as goal for photovoltaic modules in commercial energy-generating plants.

  11. Optical conductivity of amorphous Ta and beta-Ta films

    NASA Technical Reports Server (NTRS)

    Nestell, J. E., Jr.; Scoles, K. J.; Christy, R. W.

    1982-01-01

    Tantalum films evaporated in high vacuum onto liquid-nitrogen-cooled substrates had an amorphous structure that persisted even after warming to room temperature. The optical conductivity (as well as the dc conductivity) of the amorphous films differed significantly from that of the bcc films.

  12. Amorphization of SiC under ion and neutron irradiation

    NASA Astrophysics Data System (ADS)

    Snead, L. L.; Zinkle, S. J.; Hay, J. C.; Osborne, M. C.

    1998-05-01

    This paper presents results on the microstructure and physical properties of SiC amorphized by both ion and neutron irradiation. Specifically, 0.56 MeV Si ions have been implanted in single crystal 6H-SiC from ambient through >200°C and the critical threshold for amorphization was measured as a function of the irradiation temperature. From a high resolution transmission electron microscopy (HRTEM) study of the crystalline to amorphous transition region in these materials, elongated pockets of amorphous material oriented parallel to the free surface are observed. Single crystal 6H-SiC and hot pressed and sintered 6H and 3C SiC were neutron irradiated at approximately 70°C to a dose of ˜2.56 dpa causing complete amorphization. Property changes resulting from the crystal to amorphous transition in SiC include a density decrease of 10.8%, a hardness decrease from 38.7 to 21.0 GPa, and a decrease in elastic modulus from 528 to 292 GPa. Recrystallization of the amorphized, single crystal 6H-SiC appears to occur in two stages. In the temperature range of ˜800-1000°C, crystallites nucleate and slowly grow. In the temperature range of 1125-1150°C spontaneous nucleation and rapid growth of crystallites occur. It is further noted that amorphized 6H (alpha) SiC recrystallizes to highly faulted fcc (beta) SiC.

  13. Quantifying Nanoscale Order in Amorphous Materials via Fluctuation Electron Microscopy

    ERIC Educational Resources Information Center

    Bogle, Stephanie Nicole

    2009-01-01

    Fluctuation electron microscopy (FEM) has been used to study the nanoscale order in various amorphous materials. The method is explicitly sensitive to 3- and 4-body atomic correlation functions in amorphous materials; this is sufficient to establish the existence of structural order on the nanoscale, even when the radial distribution function…

  14. Addressing the amorphous content issue in quantitative phase analysis

    NASA Astrophysics Data System (ADS)

    Cline, J. P.; Dreele, R. B. Von; Winburn, R.; Stephens, P. W.; Filliben, J. J.

    2011-07-01

    A novel method is used to determine the amorphous content in the certification of NIST standard reference material (SRM) 676a (corundum). Extrapolation of diffraction measurements from mixtures with Si powders of varying surface-to-volume ratio show that approximately 1% by weight of SRM 676a is amorphous.

  15. Magnetic flux distribution in the amorphous modular transformers

    NASA Astrophysics Data System (ADS)

    Tomczuk, B.; Koteras, D.

    2011-06-01

    3D magnetic fluxes in one-phase and three-phase transformers with amorphous modular cores have been studied. Scalar potentials were implemented for the 3D Finite Element field calculation. Due to the inability to simulate each thin amorphous layer, we introduced supplementary permeabilities along the main directions of magnetization. The calculated fluxes in the cores were tested on the prototypes.

  16. Thermodynamic properties and amorphization of Zr-Si melts

    NASA Astrophysics Data System (ADS)

    Arutyunyan, N. A.; Zaitsev, A. I.; Dunaev, S. F.; Shaposhnikov, N. G.

    2016-02-01

    The relationship between the thermodynamic properties of Zr-Si liquid alloys and their propensity to amorphization is studied. The temperature-concentration dependences of the thermodynamic properties of melts are presented using the concept of associated solutions. It is shown that the range of amorphization coincides with the range of the predominant concentration of Zr3Si associative groups with low formation entropy.

  17. Superlattice doped layers for amorphous silicon photovoltaic cells

    DOEpatents

    Arya, Rajeewa R.

    1988-01-12

    Superlattice doped layers for amorphous silicon photovoltaic cells comprise a plurality of first and second lattices of amorphous silicon alternatingly formed on one another. Each of the first lattices has a first optical bandgap and each of the second lattices has a second optical bandgap different from the first optical bandgap. A method of fabricating the superlattice doped layers also is disclosed.

  18. Polarization effects in femtosecond laser induced amorphization of monocrystalline silicon

    NASA Astrophysics Data System (ADS)

    Bai, Feng; Li, Hong-Jin; Huang, Yuan-Yuan; Fan, Wen-Zhong; Pan, Huai-Hai; Wang, Zhuo; Wang, Cheng-Wei; Qian, Jing; Li, Yang-Bo; Zhao, Quan-Zhong

    2016-10-01

    We have used femtosecond laser pulses to ablate monocrystalline silicon wafer. Raman spectroscopy and X-ray diffraction analysis of ablation surface indicates horizontally polarized laser beam shows an enhancement in amorphization efficiency by a factor of 1.6-1.7 over the circularly polarized laser ablation. This demonstrates that one can tune the amorphization efficiency through the polarization of irradiation laser.

  19. Electrically conducting ternary amorphous fully oxidized materials and their application

    NASA Technical Reports Server (NTRS)

    Giauque, Pierre (Inventor); Nicolet, Marc (Inventor); Gasser, Stefan M. (Inventor); Kolawa, Elzbieta A. (Inventor); Cherry, Hillary (Inventor)

    2004-01-01

    Electrically active devices are formed using a special conducting material of the form Tm--Ox mixed with SiO2 where the materials are immiscible. The immiscible materials are forced together by using high energy process to form an amorphous phase of the two materials. The amorphous combination of the two materials is electrically conducting but forms an effective barrier.

  20. Amorphization and nanocrystallization of silcon under shock compression

    DOE PAGES

    Remington, B. A.; Wehrenberg, C. E.; Zhao, S.; ...

    2015-11-06

    High-power, short-duration, laser-driven, shock compression and recovery experiments on [001] silicon unveiled remarkable structural changes above a pressure threshold. Two distinct amorphous regions were identified: (a) a bulk amorphous layer close to the surface and (b) amorphous bands initially aligned with {111} slip planes. Further increase of the laser energy leads to the re-crystallization of amorphous silicon into nanocrystals with high concentration of nano-twins. This amorphization is produced by the combined effect of high magnitude hydrostatic and shear stresses under dynamic shock compression. Shock-induced defects play a very important role in the onset of amorphization. Calculations of the free energymore » changes with pressure and shear, using the Patel-Cohen methodology, are in agreement with the experimental results. Molecular dynamics simulation corroborates the amorphization, showing that it is initiated by the nucleation and propagation of partial dislocations. As a result, the nucleation of amorphization is analyzed qualitatively by classical nucleation theory.« less

  1. Buried anode lithium thin film battery and process for forming the same

    DOEpatents

    Lee, Se-Hee; Tracy, C. Edwin; Liu, Ping

    2004-10-19

    A reverse configuration, lithium thin film battery (300) having a buried lithium anode layer (305) and process for making the same. The present invention is formed from a precursor composite structure (200) made by depositing electrolyte layer (204) onto substrate (201), followed by sequential depositions of cathode layer (203) and current collector (202) on the electrolyte layer. The precursor is subjected to an activation step, wherein a buried lithium anode layer (305) is formed via electroplating a lithium anode layer at the interface of substrate (201) and electrolyte film (204). The electroplating is accomplished by applying a current between anode current collector (201) and cathode current collector (202).

  2. [The taphonomic aspects of cadaverous changes in corpses, buried in the plastic foils].

    PubMed

    Stuller, F; Straka, L; Macko, V; Krivos, D; Krajcovic, J; Novomeský, F

    2008-10-01

    The forensic expertise of the 6 human bodies, being murdered in organised crime activities, had been realised by the authors. All the cadavers were packed in plastic bags or plastic foils, then buried to the illegal graves, being prepared in advance. The detail overlook and autopsy of the bodies had disclosed, that due of almost airtight sealing of the cadavers in plastic materials, the postmortal cadaverous changes went on much slower and were manifested under a different picture, as seen in the human cadavers being buried in the standard wooden coffins. The authors point out the peculiarities of such a postmortal changes, with particular focusing on the estimation of postmortal period.

  3. Performance-Based Technology Selection Filter description report. INEL Buried Waste Integrated Demonstration System Analysis project

    SciTech Connect

    O`Brien, M.C.; Morrison, J.L.; Morneau, R.A.; Rudin, M.J.; Richardson, J.G.

    1992-05-01

    A formal methodology has been developed for identifying technology gaps and assessing innovative or postulated technologies for inclusion in proposed Buried Waste Integrated Demonstration (BWID) remediation systems. Called the Performance-Based Technology Selection Filter, the methodology provides a formalized selection process where technologies and systems are rated and assessments made based on performance measures, and regulatory and technical requirements. The results are auditable, and can be validated with field data. This analysis methodology will be applied to the remedial action of transuranic contaminated waste pits and trenches buried at the Idaho National Engineering Laboratory (INEL).

  4. Behavior of pipelines buried in SCP-improved ground during earthquakes

    SciTech Connect

    Fuchida, Kunihiko; Akiyoshi, Takashi; Hyodo, Takeshi

    1995-12-31

    Behavior of pipelines buried in the improved ground by sand compaction pile (SCP) and subjected to permanent ground displacement induced by liquefaction is investigated. Combining the programs for the simulation of SCP-improvement, the liquefaction analysis and the permanent ground displacement, the soil spring and the input ground displacement for the analysis of pipelines are evaluated. Results of numerical computations for the pipeline responses show that SCP ground improvement is effective to prevent soil liquefaction and reduce responses of pipeline buried in SCP-improved ground.

  5. Accurate identification of periodic oscillations buried in white or colored noise using fast orthogonal search.

    PubMed

    Chon, K H

    2001-06-01

    We use a previously introduced fast orthogonal search algorithm to detect sinusoidal frequency components buried in either white or colored noise. We show that the method outperforms the correlogram, modified covariance autoregressive (MODCOVAR) and multiple-signal classification (MUSIC) methods. Fast orthogonal search method achieves accurate detection of sinusoids even with signal-to-noise ratios as low as -10 dB, and is superior at detecting sinusoids buried in 1/f noise. Since the utilized method accurately detects sinusoids even under colored noise, it can be used to extract a 1/f noise process observed in physiological signals such as heart rate and renal blood pressure and flow data.

  6. Latex-modified grouts for in-situ stabilization of buried transuranic/mixed waste

    SciTech Connect

    Allan, M.L.

    1996-06-01

    The Department of Applied Science at Brookhaven national Laboratory was requested to investigate latex-modified grouts for in-situ stabilization of buried TRU/mixed waste for INEL. The waste exists in shallow trenches that were backfilled with soil. The objective was to formulate latex-modified grouts for use with the jet grouting technique to enable in-situ stabilization of buried waste. The stabilized waste was either to be left in place or retrieved for further processing. Grouting prior to retrieval reduces the potential release of contaminants. Rheological properties of latex-modified grouts were investigated and compared with those of conventional neat cement grouts used for jet grouting.

  7. Buried Anode Device Development: Cooperative Research and Development Final Report, CRADA Number CRD-11-451

    SciTech Connect

    Tenent, Robert

    2015-03-01

    The possibility of a reflecting electrochromic device is very attractive, and the 'Buried Anode' architecture developed at NREL could yield such a device. The subject of this cooperative agreement will be the development and refinement of a Buried Anode device process. This development will require the active involvement of NREL and US e-Chromic personnel, and will require the use of NREL equipment as much as possible. When this effort is concluded, US e-Chromic will have enough information to construct a pilot production line, where further development can continue.

  8. Gate-Controlled WSe2 Transistors Using a Buried Triple-Gate Structure

    NASA Astrophysics Data System (ADS)

    Müller, M. R.; Salazar, R.; Fathipour, S.; Xu, H.; Kallis, K.; Künzelmann, U.; Seabaugh, A.; Appenzeller, J.; Knoch, J.

    2016-11-01

    In the present paper, we show tungsten diselenide (WSe2) devices that can be tuned to operate as n-type and p-type field-effect transistors (FETs) as well as band-to-band tunnel transistors on the same flake. Source, channel, and drain areas of the WSe2 flake are adjusted, using buried triple-gate substrates with three independently controllable gates. The device characteristics found in the tunnel transistor configuration are determined by the particular geometry of the buried triple-gate structure, consistent with a simple estimation of the expected off-state behavior.

  9. Micro-buried spiral zone plate in a lithium niobate crystal

    NASA Astrophysics Data System (ADS)

    Tian, Zhen-Nan; Hua, Jian-Guan; Hao, Juan; Yu, Yan-Hao; Chen, Qi-Dai; Sun, Hong-Bo

    2017-01-01

    We present a micro-buried spiral zone plate (MBSZP) in the lithium niobate crystal fabricated with femtosecond laser direct writing technology. The microstructures of the MBSZP are buried under the surface of the crystal, which ensures the stability of the optical performance in various refractive index environments. The optical performances of imaging and focusing capabilities were demonstrated. In addition, the experiment showed good agreement with simulation results based on the optical wave propagation method. This novel optical element will have important applications in multistate information encoding, optical manipulation, quantum communication, and computation, especially in high integration, contact coupling, and variable refractive index environments.

  10. Buried waste integrated demonstration fiscal year 1992 close-out report

    SciTech Connect

    Cannon, P.G.; Kostelnik, K.M.; Owens, K.J.

    1993-02-01

    The mission of the Buried Waste Integrated Demonstration Program (BWID) is to support the development and demonstration of a suite of technologies that when integrated with commercially-available baseline technologies form a comprehensive remediation system for the effective and efficient remediation of buried waste disposed of throughout the US Department of Energy complex. To accomplish this mission of identifying technological solutions for remediation deficiencies, the Office of Technology Development initiated the BWID at the Idaho National Engineering Laboratory in fiscal year (FY)-91. This report summarizes the activities of the BWID Program during FY-92.

  11. Real-time buried threat detection and cueing capability in VPEF environment

    NASA Astrophysics Data System (ADS)

    Ling, Bo; Agarwal, Sanjeev; Olivera, Santiago; Vasilkoski, Zlatko; Phan, Chung; Geyer, Chris

    2015-05-01

    In this paper, we present a vehicular buried threat detection approach developed over the past several years, and its latest implementation and integration in VPEF environment. Buried threats have varying signatures under different operation environment. To reliably detect the true targets and minimizing the number of false alarms, a suite of false alarm mitigators (FAMs) have been developed to process the potential targets identified by the baseline module. A vehicle track can be formed over a number of frames and targets are further analyzed both spatially and temporally. Algorithms have been implemented in C/C++ as GStreamer plugins and are suitable for vehicle mounted, on-the-move realtime exploitation.

  12. Tritiated amorphous silicon films and devices

    NASA Astrophysics Data System (ADS)

    Kosteski, Tome

    The do saddle-field glow discharge deposition technique has been used to bond tritium within an amorphous silicon thin film network using silane and elemental tritium in the glow discharge. The concentration of tritium is approximately 7 at. %. Minimal outgassing of tritium from tritiated hydrogenated amorphous silicon (a-Si:H:T) at room temperature suggests that tritium is bonded stably. Tritium effusion only occurred at temperatures above the film's growth temperature. The radioactive decay of tritium results in the production of high-energy beta particles. Each beta particle can generate on average approximately 1300 electron-hole pairs in a-Si:H:T. Electrical conductivity of a-Si:H:T is shown to be due to a thermally activated process and due to the generation of excess carriers by the beta particles. p-i-n betavoltaic devices have been made with a-Si:H:T in the intrinsic (i-) region. The i-region consisted of either a-Si:H:T, or a thin section of a-Si:H:T (a Delta layer) sandwiched between undoped hydrogenated amorphous silicon (a-Si:H). The excess carriers generated in the i-region are separated by the device's built-in electric field. Short-circuit currents (Isc ), open-circuit voltages (Voc), and power have been measured and correlated to the generation of excess carriers in the i-region. Good devices were made at a substrate temperature of 250°C and relatively large flow rates of silane and tritium; this ensures that there are more monohydride bonds than dihydride bonds. Under dark conditions, Isc, and Voc have been found to decrease rapidly. This is consistent with the production of silicon neutral dangling bonds (5 x 1017cm-3 per day) from the loss of tritium due to its transmutation into helium. Dangling bonds reduce carrier lifetime and weaken the electric field in the i-region. The short-circuit current from Delta layer devices decreased more slowly and settled to higher values for narrower Delta layers. This is because the dangling bonds are

  13. Amorphous molybdenum sulfides as hydrogen evolution catalysts.

    PubMed

    Morales-Guio, Carlos G; Hu, Xile

    2014-08-19

    Providing energy for a population projected to reach 9 billion people within the middle of this century is one of the most pressing societal issues. Burning fossil fuels at a rate and scale that satisfy our near-term demand will irreversibly damage the living environment. Among the various sources of alternative and CO2-emission-free energies, the sun is the only source that is capable of providing enough energy for the whole world. Sunlight energy, however, is intermittent and requires an efficient storage mechanism. Sunlight-driven water splitting to make hydrogen is widely considered as one of the most attractive methods for solar energy storage. Water splitting needs a hydrogen evolution catalyst to accelerate the rate of hydrogen production and to lower the energy loss in this process. Precious metals such as Pt are superior catalysts, but they are too expensive and scarce for large-scale applications. In this Account, we summarize our recent research on the preparation, characterization, and application of amorphous molybdenum sulfide catalysts for the hydrogen evolution reaction. The catalysts can be synthesized by electrochemical deposition under ambient conditions from readily available and inexpensive precursors. The catalytic activity is among the highest for nonprecious catalysts. For example, at a loading of 0.2 mg/cm(2), the optimal catalyst delivers a current density of 10 mA/cm(2) at an overpotential of 160 mV. The growth mechanism of the electrochemically deposited film catalysts was revealed by an electrochemical quartz microcrystal balance study. While different electrochemical deposition methods produce films with different initial compositions, the active catalysts are the same and are identified as a "MoS(2+x)" species. The activity of the film catalysts can be further promoted by divalent Fe, Co, and Ni ions, and the origins of the promotional effects have been probed. Highly active amorphous molybdenum sulfide particles can also be prepared

  14. Construction and characterization of amorphous-silicon test structures

    SciTech Connect

    Koppel, L.N.; Milgram, A.A.

    1987-08-01

    Semiconductor device fabrication and characterization work indicates that construction of amorphous-Si photoconductive radiation detectors is feasible. Amorphous Si films are mechanically stable and adhere well to candidate electrode materials; form Schottky-type rectifying junctions with several electrode metals. Materials exist for forming ohmic contacts on amorphous-Si films. Fabrication facilities accessible to ARACOR produce material of nominal band-gap energy, dangling bond density, and dielectric constant. Modification of amorphous-Si conductivity is feasible and supports the construction of PIN devices. Significant photoconductive response is observed for both Schottky-type and PIN devices, with the latter providing superior performance. It is recommended that construction and experimental evaluation of prototype amorphous-Si radiation detectors be persued in Phase II.

  15. Atomistic simulation of damage accumulation and amorphization in Ge

    SciTech Connect

    Gomez-Selles, Jose L. Martin-Bragado, Ignacio; Claverie, Alain; Benistant, Francis

    2015-02-07

    Damage accumulation and amorphization mechanisms by means of ion implantation in Ge are studied using Kinetic Monte Carlo and Binary Collision Approximation techniques. Such mechanisms are investigated through different stages of damage accumulation taking place in the implantation process: from point defect generation and cluster formation up to full amorphization of Ge layers. We propose a damage concentration amorphization threshold for Ge of ∼1.3 × 10{sup 22} cm{sup −3} which is independent on the implantation conditions. Recombination energy barriers depending on amorphous pocket sizes are provided. This leads to an explanation of the reported distinct behavior of the damage generated by different ions. We have also observed that the dissolution of clusters plays an important role for relatively high temperatures and fluences. The model is able to explain and predict different damage generation regimes, amount of generated damage, and extension of amorphous layers in Ge for different ions and implantation conditions.

  16. Pressure-Induced Structural Transformation in Radiation-Amorphized Zircon

    SciTech Connect

    Trachenko, Kostya; Dove, Martin T.; Salje, E. K. H.; Brazhkin, V. V.; Tsiok, O. B.

    2007-03-30

    We study the response of a radiation-amorphized material to high pressure. We have used zircon ZrSiO{sub 4} amorphized by natural radiation over geologic times, and have measured its volume under high pressure, using the precise strain-gauge technique. On pressure increase, we observe apparent softening of the material, starting from 4 GPa. Using molecular dynamics simulation, we associate this softening with the amorphous-amorphous transformation accompanied by the increase of local coordination numbers. We observe permanent densification of the quenched sample and a nontrivial 'pressure window' at high temperature. These features point to a new class of amorphous materials that show a response to pressure which is distinctly different from that of crystals.

  17. Pressure-induced structural transformation in radiation-amorphized zircon.

    PubMed

    Trachenko, Kostya; Brazhkin, V V; Tsiok, O B; Dove, Martin T; Salje, E K H

    2007-03-30

    We study the response of a radiation-amorphized material to high pressure. We have used zircon ZrSiO4 amorphized by natural radiation over geologic times, and have measured its volume under high pressure, using the precise strain-gauge technique. On pressure increase, we observe apparent softening of the material, starting from 4 GPa. Using molecular dynamics simulation, we associate this softening with the amorphous-amorphous transformation accompanied by the increase of local coordination numbers. We observe permanent densification of the quenched sample and a nontrivial "pressure window" at high temperature. These features point to a new class of amorphous materials that show a response to pressure which is distinctly different from that of crystals.

  18. Direct-patterned optical waveguides on amorphous silicon films

    DOEpatents

    Vernon, Steve; Bond, Tiziana C.; Bond, Steven W.; Pocha, Michael D.; Hau-Riege, Stefan

    2005-08-02

    An optical waveguide structure is formed by embedding a core material within a medium of lower refractive index, i.e. the cladding. The optical index of refraction of amorphous silicon (a-Si) and polycrystalline silicon (p-Si), in the wavelength range between about 1.2 and about 1.6 micrometers, differ by up to about 20%, with the amorphous phase having the larger index. Spatially selective laser crystallization of amorphous silicon provides a mechanism for controlling the spatial variation of the refractive index and for surrounding the amorphous regions with crystalline material. In cases where an amorphous silicon film is interposed between layers of low refractive index, for example, a structure comprised of a SiO.sub.2 substrate, a Si film and an SiO.sub.2 film, the formation of guided wave structures is particularly simple.

  19. Salt Fog Testing Iron-Based Amorphous Alloys

    SciTech Connect

    Rebak, Raul B.; Aprigliano, Louis F.; Day, S. Daniel; Farmer, Joseph C.

    2007-07-01

    Iron-based amorphous alloys are hard and highly corrosion resistant, which make them desirable for salt water and other applications. These alloys can be produced as powder and can be deposited as coatings on any surface that needs to be protected from the environment. It was of interest to examine the behavior of these amorphous alloys in the standard salt-fog testing ASTM B 117. Three different amorphous coating compositions were deposited on 316L SS coupons and exposed for many cycles of the salt fog test. Other common engineering alloys such as 1018 carbon steel, 316L SS and Hastelloy C-22 were also tested together with the amorphous coatings. Results show that amorphous coatings are resistant to rusting in salt fog. Partial devitrification may be responsible for isolated rust spots in one of the coatings. (authors)

  20. Fabrication and Characterization of Amorphous/Nanocrystalline Thin Film Composite

    NASA Astrophysics Data System (ADS)

    Newton, Benjamin S.

    Combining the absorption abilities of amorphous silicon and the electron transport capabilities of crystalline silicon would be a great advantage to not only solar cells but other semiconductor devices. In this work composite films were created using molecular beam epitaxy and electron beam deposition interchangeably as a method to create metallic precursors. Aluminum induced crystallization techniques were used to convert an amorphous silicon film with a capping layer of aluminum nanodots into a film composed of a mixture of amorphous silicon and nanocrystalline silicon. This layer was grown into the amorphous layer by cannibalizing a portion of the amorphous silicon material during the aluminum induced crystallization. Characterization was performed on films and metallic precursors utilizing SEM, TEM, ellipsometry and spectrophotometer.

  1. Mechanism of solid state amorphization of glucose upon milling.

    PubMed

    Dujardin, N; Willart, J F; Dudognon, E; Danède, F; Descamps, M

    2013-02-07

    Crystalline α-glucose is known to amorphize upon milling at -15 °C while it remains structurally invariant upon milling at room temperature. We have taken advantage of this behavior to compare the microstructural evolutions of the material in both conditions in order to identify the essential microstructural features which drive the amorphization process upon milling. The investigations have been performed by differential scanning calorimetry and by powder X-ray diffraction. The results indicate that two different amorphization mechanisms occur upon milling: an amorphization at the surface of crystallites due to the mechanical shocks and a spontaneous amorphization of the crystallites as they reach a critical size, which is close to 200 Å in the particular case of α-glucose.

  2. A comprehensive inventory of radiological and nonradiological contaminants in waste buried or projected to be buried in the subsurface disposal area of the INEL RWMC during the years 1984-2003, Volume 2

    SciTech Connect

    1995-05-01

    This is the second volume of this comprehensive report of the inventory of radiological and nonradiological contaminants in waste buried or projected to be buried in the subsurface disposal area of the Idaho National Engineering Laboratory. Appendix B contains a complete printout of contaminant inventory and other information from the CIDRA Database and is presented in volumes 2 and 3 of the report.

  3. High-Density Amorphous Ice, the Frost on Interstellar Grains

    NASA Technical Reports Server (NTRS)

    Jenniskens, P.; Blake, D. F.; Wilson, M. A.; Pohorille, A.

    1995-01-01

    Most water ice in the universe is in a form which does not occur naturally on Earth and of which only minimal amounts have been made in the laboratory. We have encountered this 'high-density amorphous ice' in electron diffraction experiments of low-temperature (T less than 30 K) vapor-deposited water and have subsequently modeled its structure using molecular dynamics simulations. The characteristic feature of high-density amorphous ice is the presence of 'interstitial' oxygen pair distances between 3 and 4 A. However, we find that the structure is best described as a collapsed lattice of the more familiar low-density amorphous form. These distortions are frozen in at temperatures below 38 K because, we propose, it requires the breaking of one hydrogen bond, on average, per molecule to relieve the strain and to restructure the lattice to that of low-density amorphous ice. Several features of astrophysical ice analogs studied in laboratory experiments are readily explained by the structural transition from high-density amorphous ice into low-density amorphous ice. Changes in the shape of the 3.07 gm water band, trapping efficiency of CO, CO loss, changes in the CO band structure, and the recombination of radicals induced by low-temperature UV photolysis all covary with structural changes that occur in the ice during this amorphous to amorphous transition. While the 3.07 micrometers ice band in various astronomical environments can be modeled with spectra of simple mixtures of amorphous and crystalline forms, the contribution of the high-density amorphous form nearly always dominates.

  4. Characteristics of amorphous kerogens fractionated from terrigenous sedimentary rocks

    NASA Astrophysics Data System (ADS)

    Suzuki, Noriyuki

    1984-02-01

    A preliminary attempt to fractionate amorphous kerogens from terrigenous bulk kerogen by a benzene-water two phase partition method under acidic condition was made. Microscopic observation revealed that amorphous kerogens and structured kerogens were fractionated effectively by this method. Characteristics of the amorphous and structured kerogens fractionated by this method were examined by some chemical analyses and compared with those of the bulk kerogen and humic acid isolated from the same rock sample (Haizume Formation, Pleistocene, Japan). The elemental and infrared (IR) analyses showed that the amorphous kerogen fraction had the highest atomic H/C ratio and the lowest atomic N/C ratio and was the richest in aliphatic structures and carbonyl and carboxyl functional groups. Quantities of fatty acids from the saponification products of each geopolymer were in agreement with the results of elemental and IR analyses. Distribution of the fatty acids was suggestive that more animal lipids participate in the formation of amorphous kerogens because of the abundance of relatively lower molecular weight fatty acids (such as C 16 and C 18 acids) in saponification products of amorphous kerogens. On the other hand, although the amorphous kerogen fraction tends to be rich in aliphatic structures compared with bulk kerogen of the same rock samples, van Krevelen plots of elemental compositions of kerogens from the core samples (Nishiyama Oil Field, Tertiary, Japan) reveal that the amorphous kerogen fraction is not necessarily characterized by markedly high atomic H/C ratio. This was attributed to the oxic environment of deposition and the abundance of biodegraded terrestrial amorphous organic matter in the amorphous kerogen fraction used in this work.

  5. Theoretical studies of amorphous silicon and hydrogenated amorphous silicon with molecular dynamics simulations

    SciTech Connect

    Kwon, I.

    1991-12-20

    Amorphous silicon (a-Si) and hydrogenated amorphous silicon (a-Si:H) have been studied with molecular dynamics simulations. The structural, vibrational, and electronic properties of these materials have been studied with computer-generated structural models and compare well with experimental observations. The stability of a-si and a-Si:H have been studied with the aim of understanding microscopic mechanisms underlying light-induced degradation in a-Si:H (the Staebler-Wronski effect). With a view to understanding thin film growth processes, a-Si films have been generated with molecular dynamics simulations by simulating the deposition of Si-clusters on a Si(111) substrate. A new two- and three-body interatomic potential for Si-H interactions has been developed. The structural properties of a-Si:H networks are in good agreement with experimental measurements. The presence of H atoms reduces strain and disorder relative to networks without H.

  6. Structural relaxation of vacancies in amorphous silicon

    SciTech Connect

    Kim, E.; Lee, Y.H.; Chen, C.; Pang, T.

    1997-07-01

    The authors have studied the structural relaxation of vacancies in amorphous silicon (a-Si) using a tight-binding molecular-dynamics method. The most significant difference between vacancies in a-Si and those in crystalline silicon (c-Si) is that the deep gap states do not show up in a-Si. This difference is explained through the unusual behavior of the structural relaxation near the vacancies in a-Si, which enhances the sp{sup 2} + p bonding near the band edges. They have also observed that the vacancies do not migrate below 450 K although some of them can still be annihilated, particularly at high defect density due to large structural relaxation.

  7. Polarization Stability of Amorphous Piezoelectric Polyimides

    NASA Technical Reports Server (NTRS)

    Park, C.; Ounaies, Z.; Su, J.; Smith, J. G., Jr.; Harrison, J. S.

    2000-01-01

    Amorphous polyimides containing polar functional groups have been synthesized and investigated for potential use as high temperature piezoelectric sensors. The thermal stability of the piezoelectric effect of one polyimide was evaluated as a function of various curing and poling conditions under dynamic and static thermal stimuli. First, the polymer samples were thermally cycled under strain by systematically increasing the maximum temperature from 50 C to 200 C while the piezoelectric strain coefficient was being measured. Second, the samples were isothermally aged at an elevated temperature in air, and the isothermal decay of the remanent polarization was measured at room temperature as a function of time. Both conventional and corona poling methods were evaluated. This material exhibited good thermal stability of the piezoelectric properties up to 100 C.

  8. Amorphous materials molded IR lens progress report

    NASA Astrophysics Data System (ADS)

    Hilton, A. R., Sr.; McCord, James; Timm, Ronald; Le Blanc, R. A.

    2008-04-01

    Amorphous Materials began in 2000 a joint program with Lockheed Martin in Orlando to develop molding technology required to produce infrared lenses from chalcogenide glasses. Preliminary results were reported at this SPIE meeting by Amy Graham1 in 2003. The program ended in 2004. Since that time, AMI has concentrated on improving results from two low softening glasses, Amtir 4&5. Both glasses have been fully characterized and antireflection coatings have been developed for each. Lenses have been molded from both glasses, from Amtir 6 and from C1 Core glass. A Zygo unit is used to evaluate the results of each molded lens as a guide to improving the molding process. Expansion into a larger building has provided room for five production molding units. Molded lens sizes have ranged from 8 mm to 136 mm in diameter. Recent results will be presented

  9. Negative Magnetoresistance in Amorphous Indium Oxide Wires

    NASA Astrophysics Data System (ADS)

    Mitra, Sreemanta; Tewari, Girish C.; Mahalu, Diana; Shahar, Dan

    2016-11-01

    We study magneto-transport properties of several amorphous Indium oxide nanowires of different widths. The wires show superconducting transition at zero magnetic field, but, there exist a finite resistance at the lowest temperature. The R(T) broadening was explained by available phase slip models. At low field, and far below the superconducting critical temperature, the wires with diameter equal to or less than 100 nm, show negative magnetoresistance (nMR). The magnitude of nMR and the crossover field are found to be dependent on both temperature and the cross-sectional area. We find that this intriguing behavior originates from the interplay between two field dependent contributions.

  10. Extracting Crystal Chemistry from Amorphous Carbon Structures.

    PubMed

    Deringer, Volker L; Csányi, Gábor; Proserpio, Davide M

    2017-03-08

    Carbon allotropes have been explored intensively by ab initio crystal structure prediction, but such methods are limited by the large computational cost of the underlying density functional theory (DFT). Here we show that a novel class of machine-learning-based interatomic potentials can be used for random structure searching and readily predicts several hitherto unknown carbon allotropes. Remarkably, our model draws structural information from liquid and amorphous carbon exclusively, and so does not have any prior knowledge of crystalline phases: it therefore demonstrates true transferability, which is a crucial prerequisite for applications in chemistry. The method is orders of magnitude faster than DFT and can, in principle, be coupled with any algorithm for structure prediction. Machine-learning models therefore seem promising to enable large-scale structure searches in the future.

  11. Thermomechanical behavior of amorphous tactic methacrylate polymers

    NASA Technical Reports Server (NTRS)

    Kiran, E.; Gillham, J. K.; Gipstein, E.

    1974-01-01

    Dynamic mechanical spectra of amorphous stereoregular poly(methyl methacrylate)s and poly(t-butyl methacrylate)s with assigned microtacticities are presented and discussed. An intermolecular argument is invoked to account for the higher glass transition temperature of syndiotactic vis a vis isotactic PMMA, in spite of the higher density of the latter at 30 C. An argument is presented to show that the ratio of glassy-region relaxation temperature to glass transition temperature is not only a measure of the degree of coupling of the beta and glass transition processes, but also of the degree to which intermolecular factors influence these processes. The greater extent of the low-temperature irreversibilities observed in the thermomechanical spectra of poly(t-butyl methacrylate)s is attributed to the brittle character induced by the bulky side groups which presumably weaken cohesive forces.

  12. Tunable plasticity in amorphous silicon carbide films.

    PubMed

    Matsuda, Yusuke; Kim, Namjun; King, Sean W; Bielefeld, Jeff; Stebbins, Jonathan F; Dauskardt, Reinhold H

    2013-08-28

    Plasticity plays a crucial role in the mechanical behavior of engineering materials. For instance, energy dissipation during plastic deformation is vital to the sufficient fracture resistance of engineering materials. Thus, the lack of plasticity in brittle hybrid organic-inorganic glasses (hybrid glasses) often results in a low fracture resistance and has been a significant challenge for their integration and applications. Here, we demonstrate that hydrogenated amorphous silicon carbide films, a class of hybrid glasses, can exhibit a plasticity that is even tunable by controlling their molecular structure and thereby leads to an increased and adjustable fracture resistance in the films. We decouple the plasticity contribution from the fracture resistance of the films by estimating the "work-of-fracture" using a mean-field approach, which provides some insight into a potential connection between the onset of plasticity in the films and the well-known rigidity percolation threshold.

  13. Radiation resistance studies of amorphous silicon films

    NASA Technical Reports Server (NTRS)

    Payson, J. Scott; Woodyard, James R.

    1988-01-01

    A study of hydrogenated amorphous silicon thin films irradiated with 2.00 MeV helium ions using fluences ranging from 1E11 to 1E15/sq cm is presented. The films were characterized using photothermal deflection spectroscopy, transmission and reflection spectroscopy, and photoconductivity and annealing measurements. Large changes were observed in the subband-gap optical absorption for energies between 0.9 and 1.7 eV. The steady-state photoconductivity showed decreases of almost five orders of magnitude for a fluence of 1E15/sq cm, but the slope of the intensity dependence of the photoconductivity remained almost constant for all fluences. Substantial annealing occurs even at room temperature, and for temperatures greater than 448 K the damage is completely annealed. The data are analyzed to describe the defects and the density of states function.

  14. Energy landscape of relaxed amorphous silicon

    NASA Astrophysics Data System (ADS)

    Valiquette, Francis; Mousseau, Normand

    2003-09-01

    We analyze the structure of the energy landscape of a well-relaxed 1000-atom model of amorphous silicon using the activation-relaxation technique (ART nouveau). Generating more than 40 000 events starting from a single minimum, we find that activated mechanisms are local in nature, that they are distributed uniformly throughout the model, and that the activation energy is limited by the cost of breaking one bond, independently of the complexity of the mechanism. The overall shape of the activation-energy-barrier distribution is also insensitive to the exact details of the configuration, indicating that well-relaxed configurations see essentially the same environment. These results underscore the localized nature of relaxation in this material.

  15. Negative Magnetoresistance in Amorphous Indium Oxide Wires

    PubMed Central

    Mitra, Sreemanta; Tewari, Girish C; Mahalu, Diana; Shahar, Dan

    2016-01-01

    We study magneto-transport properties of several amorphous Indium oxide nanowires of different widths. The wires show superconducting transition at zero magnetic field, but, there exist a finite resistance at the lowest temperature. The R(T) broadening was explained by available phase slip models. At low field, and far below the superconducting critical temperature, the wires with diameter equal to or less than 100 nm, show negative magnetoresistance (nMR). The magnitude of nMR and the crossover field are found to be dependent on both temperature and the cross-sectional area. We find that this intriguing behavior originates from the interplay between two field dependent contributions. PMID:27876859

  16. Spray drying formulation of amorphous solid dispersions.

    PubMed

    Singh, Abhishek; Van den Mooter, Guy

    2016-05-01

    Spray drying is a well-established manufacturing technique which can be used to formulate amorphous solid dispersions (ASDs) which is an effective strategy to deliver poorly water soluble drugs (PWSDs). However, the inherently complex nature of the spray drying process coupled with specific characteristics of ASDs makes it an interesting area to explore. Numerous diverse factors interact in an inter-dependent manner to determine the final product properties. This review discusses the basic background of ASDs, various formulation and process variables influencing the critical quality attributes (CQAs) of the ASDs and aspects of downstream processing. Also various aspects of spray drying such as instrumentation, thermodynamics, drying kinetics, particle formation process and scale-up challenges are included. Recent advances in the spray-based drying techniques are mentioned along with some future avenues where major research thrust is needed.

  17. Tailored magnetic anisotropy in an amorphous trilayer

    NASA Astrophysics Data System (ADS)

    Fu, Yu; Barsukov, I.; Raanaei, H.; Spasova, M.; Lindner, J.; Meckenstock, R.; Farle, M.; Hjörvarsson, B.

    2011-06-01

    An amorphous Co68Fe24Zr8(3 nm)/Al70Zr30(3 nm)/Co68Fe24Zr8(3 nm) trilayer system has been investigated using in-plane and out-of-plane angular dependent ferromagnetic resonance at different frequencies. The in-plane magnetic anisotropy is uniaxial, retaining its value of (2.9 ± 0.1) × 103 J/m3 for each magnetic layer, whereas its direction was tailored independently in an arbitrary manner by applying an external magnetic field during the film deposition. The perpendicular anisotropy constant, supposed to reflect the interface quality, is nearly identical for both layers. Furthermore, the magnetic layers act independently upon each other due to the absence of interlayer coupling.

  18. Spectrometric characterization of amorphous silicon PIN detectors

    NASA Astrophysics Data System (ADS)

    Leyva, A.; Ramírez, F. J.; Ortega, Y.; Estrada, M.; Cabal, A.; Cerdeira, A.; Díaz, A.

    2000-10-01

    During the last years, much interest has been dedicated to the use of amorphous silicon PIN diodes as particle and radiation detectors for medical applications. This work presents the spectrometric characterization of PECVD high deposition rate diodes fabricated at our laboratory, with thickness up to 17.5 μm. Results show that the studied devices detect the Am241 alpha particles and the medical X-rays generated by a mammograph model Senographe 700T from General Electric Possible reasons of the observed energy losses are discussed in the text. Using the SRIM2000 program, the transit of 5.5 MeV alpha particles through a diode was simulated, determining the optimum thickness for these particles to deposit their energy in the intrinsic layer of the diode.

  19. Nanostructural characterization of amorphous diamondlike carbon films

    SciTech Connect

    SIEGAL,MICHAEL P.; TALLANT,DAVID R.; MARTINEZ-MIRANDA,L.J.; BARBOUR,J. CHARLES; SIMPSON,REGINA L.; OVERMYER,DONALD L.

    2000-01-27

    Nanostructural characterization of amorphous diamondlike carbon (a-C) films grown on silicon using pulsed-laser deposition (PLD) is correlated to both growth energetic and film thickness. Raman spectroscopy and x-ray reflectivity probe both the topological nature of 3- and 4-fold coordinated carbon atom bonding and the topographical clustering of their distributions within a given film. In general, increasing the energetic of PLD growth results in films becoming more ``diamondlike'', i.e. increasing mass density and decreasing optical absorbance. However, these same properties decrease appreciably with thickness. The topology of carbon atom bonding is different for material near the substrate interface compared to material within the bulk portion of an a-C film. A simple model balancing the energy of residual stress and the free energies of resulting carbon topologies is proposed to provide an explanation of the evolution of topographical bonding clusters in a growing a-C film.

  20. Bulk amorphous steels based on Fe alloys

    DOEpatents

    Lu, ZhaoPing; Liu, Chain T.

    2006-05-30

    A bulk amorphous alloy has the approximate composition: Fe.sub.(100-a-b-c-d-e)Y.sub.aMn.sub.bT.sub.cM.sub.dX.sub.e wherein: T includes at least one of the group consisting of: Ni, Cu, Cr and Co; M includes at least one of the group consisting of W, Mo, Nb, Ta, Al and Ti; X includes at least one of the group consisting of Co, Ni and Cr; a is an atomic percentage, and a<5; b is an atomic percentage, and b.ltoreq.25; c is an atomic percentage, and c.ltoreq.25; d is an atomic percentage, and d.ltoreq.25; and e is an atomic percentage, and 5.ltoreq.e.ltoreq.30.

  1. Marijuana as doping in sports.

    PubMed

    Campos, Daniel R; Yonamine, Mauricio; de Moraes Moreau, Regina L

    2003-01-01

    A high incidence of positive cases for cannabinoids, in analyses for doping control in sports, has been observed since the International Olympic Committee (IOC) included them in the 1989 list of prohibited drugs under the title of classes of prohibited substances in certain circumstances. Where the rules of sports federations so provide, tests are conducted for marijuana, hashish or any other cannabis product exposure by means of urinalysis of 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (carboxy-THC) the main metabolite of delta-9-tetrahydrocannabinol (THC). Concentrations >15 ng/mL (cut-off value) in confirmatory analytical procedures are considered doping. Cannabis is an illicit drug in several countries and has received much attention in the media for its potential therapeutic uses and the efforts to legalise its use. Studies have demonstrated that the use of cannabinoids can reduce anxiety, but it does not have ergogenic potential in sports activities. An increase in heart rate and blood pressure, decline of cardiac output and reduced psychomotor activity are some of the pharmacological effects of THC that will determine a decrease in athletic performance. An ergolytic activity of cannabis products has been observed in athletes of several different sport categories. In Brazil, analyses for doping control in sports, performed in our laboratories, have detected positive cases for carboxy-THC in urine samples of soccer, volleyball, cycling and other athletes. It is our intention to discuss in this article some points that may discourage individuals from using cannabis products during sports activities, even in the so-called permitted circumstances defined by the IOC and some sports federations.

  2. Hormones as doping in sports.

    PubMed

    Duntas, Leonidas H; Popovic, Vera

    2013-04-01

    Though we may still sing today, as did Pindar in his eighth Olympian Victory Ode, "… of no contest greater than Olympia, Mother of Games, gold-wreathed Olympia…", we must sadly admit that today, besides blatant over-commercialization, there is no more ominous threat to the Olympic games than doping. Drug-use methods are steadily becoming more sophisticated and ever harder to detect, increasingly demanding the use of complex analytical procedures of biotechnology and molecular medicine. Special emphasis is thus given to anabolic androgenic steroids, recombinant growth hormone and erythropoietin as well as to gene doping, the newly developed mode of hormones abuse which, for its detection, necessitates high-tech methodology but also multidisciplinary individual measures incorporating educational and psychological methods. In this Olympic year, the present review offers an update on the current technologically advanced endocrine methods of doping while outlining the latest procedures applied-including both the successes and pitfalls of proteomics and metabolomics-to detect doping while contributing to combating this scourge.

  3. Phyllosilicates and Amorphous Gel in the Nakhlites

    NASA Astrophysics Data System (ADS)

    Hicks, L. J.; Bridges, J. C.; Gurman, S. J.

    2013-09-01

    Previous studies of the nakhlite martian meteorites have revealed hydrothermal minerals present within the fractures of the olivine minerals and the mesostasis. The olivine fractures of the Lafayette nakhlite reveal variations with initial deposits of siderite on the fracture walls, followed by crystalline phyllosilicates (smectite), and finishing with a rapidly cooled amorphous silicate gel within the central regions of the fractures. The mesostasis fractures of Lafayette also contain a crystalline phyllosilicate (serpentine). The amorphous gel is the most abundant secondary phase within the fractures of the other nakhlites [1, 2]. By studying nine nakhlite samples, including Lafayette, Governador Valadares, Nakhla, Y-000593, Y-000749, Miller-Range 03346, NWA 817, NWA 998, and NWA 5790, our aim is to constrain the identity of the phyllosilicate secondary phase minerals found throughout the nakhlite martian meteorites. This is achieved using methods including Electron Probe Micro-analysis (EPMA); X-ray Absorption Near-Edge Structure (Fe-K XANES) spectroscopy measured using Beamline I-18 at the Diamond Light Source synchrotron; and the use of Transmission Electron Microscopy (TEM) at the University of Leicester for High-Resolution (HR) imaging and Selected Area Electron Diffraction (SAED). BF studying nine nakhlite samples, including Lafayette, Governador Valadares, Nakhla, Y-000593, Y-000749, Miller-Range 03346, NWA 817, NWA 998, and NWA 5790, our aim is to constrain the identity of the phyllosilicate secondary phase minerals found throughout the nakhlite martian meteorites. This is achieved using methods including Electron Probe Micro-analysis (EPMA); X-ray Absorption Near-Edge Structure (Fe-K XANES) spectroscopy measured using Beamline I-18 at the Diamond Light Source synchrotron; and the use of Transmission Electron Microscopy (TEM) at the University of Leicester for High-Resolution (HR) imaging and Selected Area Electron Diffraction (SAED).

  4. Castable Amorphous Metal Mirrors and Mirror Assemblies

    NASA Technical Reports Server (NTRS)

    Hofmann, Douglas C.; Davis, Gregory L.; Agnes, Gregory S.; Shapiro, Andrew A.

    2013-01-01

    A revolutionary way to produce a mirror and mirror assembly is to cast the entire part at once from a metal alloy that combines all of the desired features into the final part: optical smoothness, curvature, flexures, tabs, isogrids, low CTE, and toughness. In this work, it has been demonstrated that castable mirrors are possible using bulk metallic glasses (BMGs, also called amorphous metals) and BMG matrix composites (BMGMCs). These novel alloys have all of the desired mechanical and thermal properties to fabricate an entire mirror assembly without machining, bonding, brazing, welding, or epoxy. BMGs are multi-component metal alloys that have been cooled in such a manner as to avoid crystallization leading to an amorphous (non-crystalline) microstructure. This lack of crystal structure and the fact that these alloys are glasses, leads to a wide assortment of mechanical and thermal properties that are unlike those observed in crystalline metals. Among these are high yield strength, carbide-like hardness, low melting temperatures (making them castable like aluminum), a thermoplastic processing region (for improving smoothness), low stiffness, high strength-to-weight ratios, relatively low CTE, density similar to titanium alloys, high elasticity and ultra-smooth cast parts (as low as 0.2-nm surface roughness has been demonstrated in cast BMGs). BMGMCs are composite alloys that consist of a BMG matrix with crystalline dendrites embedded throughout. BMGMCs are used to overcome the typically brittle failure observed in monolithic BMGs by adding a soft phase that arrests the formation of cracks in the BMG matrix. In some cases, BMGMCs offer superior castability, toughness, and fatigue resistance, if not as good a surface finish as BMGs. This work has demonstrated that BMGs and BMGMCs can be cast into prototype mirrors and mirror assemblies without difficulty.

  5. Anomalous hopping conduction in nanocrystalline/amorphous composites and amorphous semiconductor thin films

    NASA Astrophysics Data System (ADS)

    Kakalios, James; Bodurtha, Kent

    Composite nanostructured materials consisting of nanocrystals (nc) embedded within a thin film amorphous matrix can exhibit novel opto-electronic properties. Composite films are synthesized in a dual-chamber co-deposition PECVD system capable of producing nanocrystals of material A and embedding then within a thin film matrix of material B. Electronic conduction in composite thin films of hydrogenated amorphous silicon (a-Si:H) containing nc-germanium or nc-silicon inclusions, as well as in undoped a-Si:H, does not follow an Arrhenius temperature dependence, but rather is better described by an anomalous hopping expression (exp[-(To/T)3/4) , as determined from the ``reduced activation energy'' proposed by Zabrodskii and Shlimak. This temperature dependence has been observed in other thin film resistive materials, such as ultra-thin disordered films of Ag, Bi, Pb and Pd; carbon-black polymer composites; and weakly coupled Au and ZnO quantum dot arrays. There is presently no accepted theoretical understanding of this expression. The concept of a mobility edge, accepted for over four decades, appears to not be necessary to account for charge transport in amorphous semiconductors. Supported by NSF-DMR and the Minnesota Nano Center.

  6. 49 CFR 192.457 - External corrosion control: Buried or submerged pipelines installed before August 1, 1971.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false External corrosion control: Buried or submerged... SAFETY STANDARDS Requirements for Corrosion Control § 192.457 External corrosion control: Buried or... areas in which active corrosion is found: (1) Bare or ineffectively coated transmission lines. (2)...

  7. 49 CFR 192.455 - External corrosion control: Buried or submerged pipelines installed after July 31, 1971.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false External corrosion control: Buried or submerged... SAFETY STANDARDS Requirements for Corrosion Control § 192.455 External corrosion control: Buried or... against external corrosion, including the following: (1) It must have an external protective...

  8. 49 CFR 192.457 - External corrosion control: Buried or submerged pipelines installed before August 1, 1971.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false External corrosion control: Buried or submerged... SAFETY STANDARDS Requirements for Corrosion Control § 192.457 External corrosion control: Buried or... areas in which active corrosion is found: (1) Bare or ineffectively coated transmission lines. (2)...

  9. 49 CFR 192.457 - External corrosion control: Buried or submerged pipelines installed before August 1, 1971.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false External corrosion control: Buried or submerged... SAFETY STANDARDS Requirements for Corrosion Control § 192.457 External corrosion control: Buried or... areas in which active corrosion is found: (1) Bare or ineffectively coated transmission lines. (2)...

  10. 49 CFR 192.455 - External corrosion control: Buried or submerged pipelines installed after July 31, 1971.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false External corrosion control: Buried or submerged... SAFETY STANDARDS Requirements for Corrosion Control § 192.455 External corrosion control: Buried or... against external corrosion, including the following: (1) It must have an external protective...

  11. 49 CFR 192.455 - External corrosion control: Buried or submerged pipelines installed after July 31, 1971.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false External corrosion control: Buried or submerged... SAFETY STANDARDS Requirements for Corrosion Control § 192.455 External corrosion control: Buried or... minimum, soil resistivity measurements and tests for corrosion accelerating bacteria, that a...

  12. 49 CFR 192.457 - External corrosion control: Buried or submerged pipelines installed before August 1, 1971.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false External corrosion control: Buried or submerged... SAFETY STANDARDS Requirements for Corrosion Control § 192.457 External corrosion control: Buried or... areas in which active corrosion is found: (1) Bare or ineffectively coated transmission lines. (2)...

  13. 49 CFR 192.455 - External corrosion control: Buried or submerged pipelines installed after July 31, 1971.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false External corrosion control: Buried or submerged... SAFETY STANDARDS Requirements for Corrosion Control § 192.455 External corrosion control: Buried or... against external corrosion, including the following: (1) It must have an external protective...

  14. 49 CFR 192.455 - External corrosion control: Buried or submerged pipelines installed after July 31, 1971.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false External corrosion control: Buried or submerged... SAFETY STANDARDS Requirements for Corrosion Control § 192.455 External corrosion control: Buried or... against external corrosion, including the following: (1) It must have an external protective...

  15. 49 CFR 192.457 - External corrosion control: Buried or submerged pipelines installed before August 1, 1971.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false External corrosion control: Buried or submerged... SAFETY STANDARDS Requirements for Corrosion Control § 192.457 External corrosion control: Buried or... areas in which active corrosion is found: (1) Bare or ineffectively coated transmission lines. (2)...

  16. Field application of innovative grouting agents for in situ stabilization of buried waste sites

    SciTech Connect

    Loomis, G.G.; Farnsworth, R.K.

    1997-12-31

    This paper presents field applications for two innovative grouting agents that were used to in situ stabilize buried waste sites, via jet grouting. The two grouting agents include paraffin and a proprietary iron oxide based cement grout called TECT. These materials were tested in specially designed cold test pits that simulate buried transuranic waste at the Idaho National Engineering Laboratory (INEL). The field demonstrations were performed at the INEL in an area referred to as the Cold Test Pit, which is adjacent to the INEL Radioactive Waste Management Complex (RWMC). At the RWMC, 56,000 m{sup 3} of transuranic (TRU) waste is co-mingled with over 170,000 m{sup 3} of soil in shallow land burial. Improving the confinement of this waste is one of the options for final disposition of this waste. Using jet-grouting technology to inject these materials into the pore spaces of buried waste sites results in the creation of buried monolithic waste forms that simultaneously protect the waste from subsidence, while eliminating the migratory potential of hazardous and radioactive contaminants in the waste.

  17. Predicting the Distribution and Properties of Buried Submarine Topography on Continental Shelves

    DTIC Science & Technology

    2005-09-30

    added global runoff to the global river database, along with drainage basin temperature, precipitation, evapotranspiration . The database is used as...e.g. Adriatic, Gulf of Lions), or by waves (e.g. much of the coast of India ) the chance of sonar clutter from shallow buried channels is considered

  18. Testosterone reduces cumulative burying in female Wistar rats with minimal participation of estradiol.

    PubMed

    Gutiérrez-García, Ana G; Contreras, Carlos M; Vásquez-Hernández, Diana I; Molina-Jiménez, Tania; Jacome-Jacome, Emma

    2009-10-01

    Testosterone exerts anxiolytic effects, but the participation of its aromatase metabolic product estradiol is controversial. Therefore, we used the defensive burying paradigm in female Wistar rats to explore testosterone's (1.0 mg/rat, s.c.) interactions with picrotoxin (a noncompetitive gamma-aminobutyric acid-A receptor [GABA(A)] antagonist; 1.0 mg/kg, i.p.), formestane (an aromatase inhibitor; 3.0 mg/rat, s.c.), and tamoxifen (an estrogen receptor-beta antagonist; 1.0 mg/kg, s.c.). Serum levels of testosterone, estradiol, and progesterone were determined in the same rats. Burying latency and locomotion did not significantly change. Systemic testosterone administration enhanced serum testosterone and estradiol levels and reduced defensive burying. This reduction in total burying was blocked by pretreatment with picrotoxin and tamoxifen, but not formestane. We conclude that testosterone produced anxiolytic-like effects in female rats that were mediated by actions at the GABA(A) receptor, with participation of the estradiol receptor-beta, rather than estradiol aromatization.

  19. Low dose effects of a Withania somnifera extract on altered marble burying behavior in stressed mice

    PubMed Central

    Dey, Amitabha; Chatterjee, Shyam Sunder; Kumar, Vikas

    2016-01-01

    Aim: Withania somnifera root (WSR) extracts are often used in traditionally known Indian systems of medicine for prevention and cure of psychosomatic disorders. The reported experiment was designed to test whether low daily oral doses of such extracts are also effective in suppressing marble burying behavior in stressed mice or not. Materials and Methods: Groups of mice treated with 10, 20, or 40 mg/kg daily oral doses of WSR were subjected to a foot shock stress-induced hyperthermia test on the 1st, 5th, 7th, and 10th day of the experiment. On the 11th and 12th treatment days, they were subjected to marble burying tests. Stress response suppressing effects of low dose WSR were estimated by its effects on body weight and basal core temperature of animals during the course of the experiment. Results: Alterations in bodyweight and basal core temperature triggered by repeated exposures to foot shock stress were absent even in the 10 mg/kg/day WSR treated group, whereas the effectiveness of the extract in foot shock stress-induced hyperthermia and marble burying tests increased with its increasing daily dose. Conclusion: Marble burying test in stressed mice is well suited for identifying bioactive constituents of W. somnifera like medicinal plants with adaptogenic, anxiolytic and antidepressant activities, or for quantifying pharmacological interactions between them. PMID:27366354

  20. Influence of Population Density on Offspring Number and Size in Burying Beetles

    ERIC Educational Resources Information Center

    Rauter, Claudia M.

    2010-01-01

    This laboratory exercise investigates the influence of population density on offspring number and size in burying beetles. Students test the theoretical predictions that brood size declines and offspring size increases when competition over resources becomes stronger with increasing population density. Students design the experiment, collect and…

  1. Evaluating In Situ Treatment Technologies for Buried Mixed Waste Remediation at the INEEL

    SciTech Connect

    Jorgensen, Douglas Kay; Nickelson, David Frank; Nickelson, Reva Anne; Farnsworth, Richard Kent; Jessmore, James Joseph

    1999-03-01

    Mixed radioactive and hazardous wastes were buried at the Department of Energy’s Idaho National Engineering and Environmental Laboratory (INEEL) Subsurface Disposal Area from 1952 to 1969. To begin the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) remediation process for the Subsurface Disposal Area, the Environmental Protection Agency (EPA) added the INEEL to its National Priorities List in 1989. DOE’s Office of Environmental Restoration is planning several CERCLA treatability studies of remedial technologies that will be evaluated for potential remediation of the buried waste in the Subsurface Disposal Area. This paper discusses the in situ treatability studies that will be performed, including in situ vitrification, in situ grouting, and in situ thermal desorption. The in situ treatability studies will be conducted on simulated and actual buried wastes at the INEEL in 1999 and 2000. Results from the treatability studies will provide substantial information on the feasibility, implementability, and cost of applying these technologies to the INEEL Subsurface Disposal Area. In addition, much of the treatability study data will be applicable to buried waste site remediation efforts across the DOE complex.

  2. Evaluating In Situ Treatment Technologies for Buried Mixed Waste Remediation at the INEEL

    SciTech Connect

    D.F. Nickelson; D.K. Jorgensen; J.J. Jessmore; R.A. Hyde; R.K. Farnsworth

    1999-02-01

    Mixed radioactive and hazardous wastes were buried at the Department of Energy's Idaho National Engineering and Environmental Laboratory (INEEL) Subsurface Disposal Area from 1952 to 1969. To begin the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) remediation process for the Subsurface Disposal Area, the Environmental Protection Agency (EPA) added the INEEL to its National Priorities List in 1989. DOE's Office of Environmental Restoration is planning several CERCLA treatability studies of remedial technologies that will be evaluated for potential remediation of the buried waste in the Subsurface Disposal Area. This paper discusses the in situ treatability studies that will be performed, including in situ vitrification, in situ grouting, and in situ thermal desorption. The in situ treatability studies will be conducted on simulated and actual buried wastes at the INEEL in 1999 and 2000. Results from the treatability studies will provide substantial information on the feasibility, implementability, and cost of applying these technologies to the INEEL Subsurface Disposal Area. In addition, much of the treatability study data will be applicable to buried waste site remediation efforts across the DOE complex.

  3. Revealing the semiconductor–catalyst interface in buried platinum black silicon photocathodes

    SciTech Connect

    Aguiar, Jeffery A.; Anderson, Nicholas C.; Neale, Nathan R.

    2016-01-01

    Nanoporous 'black' silicon semiconductors interfaced with buried platinum nanoparticle catalysts have exhibited stable activity for photoelectrochemical hydrogen evolution even after months of exposure to ambient conditions. The mechanism behind this stability has not been explained in detail, but is thought to involve a Pt/Si interface free from SiOx layer that would adversely affect interfacial charge transfer kinetics. In this paper, we resolve the chemical composition and structure of buried Pt/Si interfaces in black silicon photocathodes from a micron to sub-nanometer level using aberration corrected analytical scanning transmission electron microscopy. Through a controlled electrodeposition of copper on samples aged for one month in ambient conditions, we demonstrate that the main active catalytic sites are the buried Pt nanoparticles located below the 400-800 nm thick nanoporous SiOx layer. Though hydrogen production performance degrades over 100 h under photoelectrochemical operating conditions, this burying strategy preserves an atomically clean catalyst/Si interface free of oxide or other phases under air exposure and provides an example of a potential method for stabilizing silicon photoelectrodes from oxidative degradation in photoelectrochemical applications.

  4. Boston's Historic Burying Grounds Initiative: An Innovative and Educational Public/Private Partnership.

    ERIC Educational Resources Information Center

    Tracy, Regina

    1988-01-01

    Discusses Boston's Historic Burying Ground Initiative, which was undertaken from a concern for public education. The public-private partnership is expected to take 10 years and six million dollars to restore the final resting places of figures such as Paul Revere, Samuel Adams, Robert Treat Paine, and the Mather family of Puritan ministers. (GEA)

  5. Bioelectrochemical denitrification on biocathode buried in simulated aquifer saturated with nitrate-contaminated groundwater.

    PubMed

    Nguyen, Van Khanh; Park, Younghyun; Yu, Jaecheul; Lee, Taeho

    2016-08-01

    Nitrate contamination in aquifers has posed human health under high risk because people still rely on groundwater withdrawn from aquifers as drinking water and running water sources. These days, bioelectrochemical technologies have shown a great number of benefits for nitrate remediation via autotrophic denitrification in groundwater. This study tested the working possibility of a denitrifying biocathode when installed into a simulated aquifer. The reactors were filled with sand and synthetic groundwater at various ratios (10, 50, and 100 %) to clarify the effect of various biocathode states (not-buried, half-buried, and fully buried) on nitrate reduction rate and microbial communities. Decreases in specific nitrate reduction rates were found to be correlated with increases in sand/medium ratios. A specific nitrate reduction rate of 322.6 mg m(-2) day(-1) was obtained when the biocathode was fully buried in an aquifer. Microbial community analysis revealed slight differences in the microbial communities of biocathodes at various sand/medium ratios. Various coccus- and rod-shaped bacteria were found to contribute to bioelectrochemical denitrification including Thiobacillus spp. and Paracoccus spp. This study demonstrated that the denitrifying biocathode could work effectively in a saturated aquifer and confirmed the feasibility of in situ application of microbial electrochemical denitrification technology.

  6. Tests of a system to exclude roots from buried radioactive waste in a warm, humid climate

    SciTech Connect

    Murphy, C.E. Jr.; Corey, J.C.; Adriano, D.C.; Decker, O.D.; Griggs, R.D.

    1989-12-31

    Vegetation is commonly used to stabilize the ground covering buried waste sites. However, constituents of buried waste can be brought to the surface if the waste is penetrated by plant roots. An ideal waste burial system would allow the use of vegetation to stabilize the soil above the buried waste but would exclude roots from the waste. One system that shows considerable promise is a slow release encapsulation of a root growth inhibitor (Trifluralin). Projected lifetimes of the capsule are in the order of 100 years. The capsule is bonded to a geotextile, which provides an easy means of distributing the capsule evenly over the area to be protected. Vegetation grown in the soil above the barrier has provided good ground cover, although some decrease in growth has been found in some species. Of the species tested the sensitivity to the biobarrier, as measured by the distance root growth stops near the barrier, is bamboo> bahia grass> bermuda grass> soybean. Potential uses for the biobarrier at the Savannah River Site (SRS) include the protection of clay caps over buried, low-level saltstone and protection of gravel drains and clay caps over decommissioned seepage basins. Trails of the biobarrier as part of waste site caps are scheduled to begin during the next 12 months.

  7. Tests of a system to exclude roots from buried radioactive waste in a warm, humid climate

    SciTech Connect

    Murphy, C.E. Jr.; Corey, J.C. ); Adriano, D.C. ); Decker, O.D.; Griggs, R.D. )

    1989-01-01

    Vegetation is commonly used to stabilize the ground covering buried waste sites. However, constituents of buried waste can be brought to the surface if the waste is penetrated by plant roots. An ideal waste burial system would allow the use of vegetation to stabilize the soil above the buried waste but would exclude roots from the waste. One system that shows considerable promise is a slow release encapsulation of a root growth inhibitor (Trifluralin). Projected lifetimes of the capsule are in the order of 100 years. The capsule is bonded to a geotextile, which provides an easy means of distributing the capsule evenly over the area to be protected. Vegetation grown in the soil above the barrier has provided good ground cover, although some decrease in growth has been found in some species. Of the species tested the sensitivity to the biobarrier, as measured by the distance root growth stops near the barrier, is bamboo> bahia grass> bermuda grass> soybean. Potential uses for the biobarrier at the Savannah River Site (SRS) include the protection of clay caps over buried, low-level saltstone and protection of gravel drains and clay caps over decommissioned seepage basins. Trails of the biobarrier as part of waste site caps are scheduled to begin during the next 12 months.

  8. Analytical model of LDMOS with a double step buried oxide layer

    NASA Astrophysics Data System (ADS)

    Yuan, Song; Duan, Baoxing; Cao, Zhen; Guo, Haijun; Yang, Yintang

    2016-09-01

    In this paper, a two-dimensional analytical model is established for the Buried Oxide Double Step Silicon On Insulator structure proposed by the authors. Based on the two-dimensional Poisson equation, the analytic expressions of the surface electric field and potential distributions for the device are achieved. In the BODS (Buried Oxide Double Step Silicon On Insulator) structure, the buried oxide layer thickness changes stepwise along the drift region, and the positive charge in the drift region can be accumulated at the corner of the step. These accumulated charge function as the space charge in the depleted drift region. At the same time, the electric field in the oxide layer also varies with the different drift region thickness. These variations especially the accumulated charge will modulate the surface electric field distribution through the electric field modulation effects, which makes the surface electric field distribution more uniform. As a result, the breakdown voltage of the device is improved by 30% compared with the conventional SOI structure. To verify the accuracy of the analytical model, the device simulation software ISE TCAD is utilized, the analytical values are in good agreement with the simulation results by the simulation software. That means the established two-dimensional analytical model for BODS structure is valid, and it also illustrates the breakdown voltage enhancement by the electric field modulation effect sufficiently. The established analytical models will provide the physical and mathematical basis for further analysis of the new power devices with the patterned buried oxide layer.

  9. Predicting Distribution and Properties of Buried Submarine Topography on Continental Shelves

    DTIC Science & Technology

    2005-09-30

    Sedimentological and stratigraphic data show that several buried paleochannels are of tidal origin, being either ancient tidal inlets or intertidal channels...Northeastern Gulf of Mexico: Geoarchaeology, v. 12, p. 417-458. Schnable, J.E., and Goodell, H.G., Pleistocene-Recent Stratigraphy , Evolution, and

  10. Impulse Loading Resulting fromShallow Buried Explosives in Water-Saturated Sand

    DTIC Science & Technology

    2007-01-01

    resembles under-water explosion. Keywords: detonation, shallow buried mine, blast loading, AUTODYN 1 INTRODUCTION Recent experience of the US military... AUTODYN , a general purpose transient non-linear dynamics explicit simulation software [9], a detailed comparison was made between the experimental...impulse pendulum with their computational counterparts obtained via detailed numerical modelling of the same physical problem using AUTODYN . The objective

  11. Dual-band, infrared buried mine detection using a statistical pattern recognition approach

    SciTech Connect

    Buhl, M.R.; Hernandez, J.E.; Clark, G.A.; Sengupta, S.K.

    1993-08-01

    The main objective of this work was to detect surrogate land mines, which were buried in clay and sand, using dual-band, infrared images. A statistical pattern recognition approach was used to achieve this objective. This approach is discussed and results of applying it to real images are given.

  12. On Resurrecting Buried Agents in Certain Tagalog Verbs. Studies in Philippine Linguistics, Vol. 3, No. 1

    ERIC Educational Resources Information Center

    Cena, R. M.

    Analysis of the deep structure of certain Tagalog sentences reveals buried agents. In Tagalog, verbs are inflected for the case role of the subject Noun Phrase (NP). However, Tagalog contains many sentences which, on the surface, do not appear to adhere to this rule, because they are missing the agent. Among sentences which deviate from the rule…

  13. Identification of immunity-related genes in the burying beetle Nicrophorus vespilloides by suppression subtractive hybridization.

    PubMed

    Vogel, H; Badapanda, C; Vilcinskas, A

    2011-12-01

    Burying beetles reproduce on small vertebrate cadavers which they bury in the soil after localization through volatiles emitted from the carcass. They then chemically preserve the carcass and prepare it as a diet for the adults and their offspring. It is predicted that exposure to high loads of soil and/or carrion-associated microbes necessitates an effective immune system. In the present paper, we report experimental screening for immunity-related genes in the burying beetle Nicrophorus vespilloides using the suppression subtractive hybridization approach. A total of 1179 putative gene objects were identified in the Nicrophorus cDNA library, which was enriched for transcripts differentially expressed upon challenge with heat-inactivated bacteria. In addition to genes known to be involved in immunity-related recognition and signalling, we found transcripts encoding for antimicrobial peptides and for an array of enzymes that can be linked to immunity or to stress-induced pathways. We also determined proteins that may contribute to detoxification of toxins produced by microbial competitors. In addition, factors involved in mRNA stability determination and central components of the RNA interference machinery were identified, implying transcriptional reprogramming and potential stress-induced retrotransposon elimination. The identified candidate immune effector and stress-related genes may provide important information about the unusual ecology and evolution of the burying beetles.

  14. Buried Seed Banks as Indicators of Seed Output along an Altitudinal Gradient.

    ERIC Educational Resources Information Center

    Thompson, K.

    1985-01-01

    Study of buried seed banks (viable seeds deposited in the soil near parent plants) provides a relatively easy way of determining cumulative effects on seed production and species' altitudinal limits. Sites, methods, validity, interpretation, problems of collection on a mountain, and germination techniques are discussed. (Author/DH)

  15. Capturing buried defects in metal interconnections with electron beam inspection system

    NASA Astrophysics Data System (ADS)

    Xiao, Hong; Jiang, Ximan; Trease, David; Van Riet, Mike; Ramprasad, Shishir; Bhatia, Anadi; Lefebvre, Pierre; Bastard, David; Moreau, Olivier; Maher, Chris; MacDonald, Paul; Campochiaro, Cecelia

    2013-04-01

    In this paper we present a novel mode of electron beam inspection (EBI), entitled super wide optics (SWO) mode, which can effectively detect buried defects in tungsten (W) plugs and copper (Cu) wires. These defects are defects of interest (DOI) to integrated circuit (IC) manufacturers because they are not detectable in optical inspection, voltage contrast (VC) mode EBI or physical mode EBI. We used engineering systems to study two samples, a tungsten chemical mechanical polish (CMP) wafer and a copper CMP wafer with a silicon carbon nitride (SiCN) cap layer. EBI with our novel SWO mode was found to capture many dark defects on these two wafers. Furthermore, defect review with all three EBI modes found some of these dark defects were unique to SWO mode. For verification, physical failure analysis was performed on some SWO-unique DOI. The cross-sectional scanning electron microscope (SEM) images and transmission electron microscope (TEM) images confirmed that the unique DOI were buried voids in W-plugs and copper wire thinning caused by either buried particles or buried particle induced metal trench under-etch. These DOI can significantly increase the resistance of metal interconnects of IC chip and affect the chip yield. This new EBI mode can provide an in-line monitoring solution for these DOI, which does not exist before this study.

  16. Identification of donor deactivation centers in heavily As-doped Si using time-of-flight medium-energy ion scattering spectroscopy

    SciTech Connect

    Min, Won Ja; Park, Kyungsu; Yu, Kyu-Sang; Joo, Sungjung; Kim, Yong-Sung; Moon, Dae Won

    2015-10-07

    Electrically-inactive arsenic (As) complexes in silicon are investigated using time-of-flight medium-energy ion scattering spectroscopy. In heavily As-doped Si, the As atoms that are segregated in the Si interface region just below the SiO{sub 2} are found to be in interstitial forms (As{sub i}), while the As atoms in the bulk Si region are found to be in the substitutional form (As{sub Si}). Despite the substitutional form of As, most of the As are found to be electrically inactive in the bulk region, and we identify the As to be in the form of a 〈111〉-oriented As{sub Si}-Si-vacancy (As{sub Si}-V{sub Si}) complex. The As{sub i} atoms in the interface Si region are found to exist together with Si-interstitial atoms (Si{sub i}), suggesting that the As{sub i} atoms in the interface Si region accompany the Si{sub i} atoms.

  17. Unveiling descriptors for predicting the bulk modulus of amorphous carbon

    NASA Astrophysics Data System (ADS)

    Takahashi, Keisuke; Tanaka, Yuzuru

    2017-02-01

    Descriptors for the bulk modulus of amorphous carbon are investigated through the implementation of data mining where data sets are prepared using first-principles calculations. Data mining reveals that the number of bonds in each C atom and the density of amorphous carbon are found to be descriptors representing the bulk modulus. Support vector regression (SVR) within machine learning is implemented and descriptors are trained where trained SVR is able to predict the bulk modulus of amorphous carbon. An inverse problem, starting from the bulk modulus towards structural information of amorphous carbon, is performed and structural information of amorphous carbon is successfully predicted from the desired bulk modulus. Thus, treating several physics factors in multidimensional space allows for the prediction of physical phenomena. In addition, the reported approach proposes that "big data" can be generated from a small data set using machine learning if descriptors are well defined. This would greatly change how amorphous carbon would be treated and help accelerate further development of amorphous carbon materials.

  18. Irradiation-induced amorphization of AlPO 4

    NASA Astrophysics Data System (ADS)

    Sreeram, A. N.; Hobbs, L. W.; Bordes, N.; Ewing, R. C.

    1996-08-01

    AlPO 4, in the mineral form berlinite, is isostructural with α-quartz. We have investigated the irradiation-induced amorphization of hydrothermally-grown berlinite and found that — like quartz and other silicas but unlike most other phosphates — it undergoes solid-state radiolyis, with an efficiency fifty times that of quartz at room temperature, and amorphizes at an absorbed ionization dose of about 1 GGy. High-resolution TEM revealed that — unlike quartz in which small amorphous inclusions nucleate — electron-irradiated AlPO 4 proceeds uniformly to an aperiodic state, much as do cristobalite and tridymite, and 20 times faster. It was found also to amorphize under 1.5 MeV Kr + ion irradiation at a collisional energy density (10 eV/atom) similar to that for quartz and in keeping with the degree of structural freedom afforded by its tetrahedral network structure. The critical ion fluence for amorphization was found to increase by a factor of 5 between 300 and 600 K. Radial distribution functions derived from energy-filtered electron diffraction patterns from regions amorphized by electrons resemble those of electron-amorphized quartz with some additional features.

  19. Amorphous Calcium Carbonate Based-Microparticles for Peptide Pulmonary Delivery.

    PubMed

    Tewes, Frederic; Gobbo, Oliviero L; Ehrhardt, Carsten; Healy, Anne Marie

    2016-01-20

    Amorphous calcium carbonate (ACC) is known to interact with proteins, for example, in biogenic ACC, to form stable amorphous phases. The control of amorphous/crystalline and inorganic/organic ratios in inhalable calcium carbonate microparticles may enable particle properties to be adapted to suit the requirements of dry powders for pulmonary delivery by oral inhalation. For example, an amorphous phase can immobilize and stabilize polypeptides in their native structure and amorphous and crystalline phases have different mechanical properties. Therefore, inhalable composite microparticles made of inorganic (i.e., calcium carbonate and calcium formate) and organic (i.e., hyaluronan (HA)) amorphous and crystalline phases were investigated for peptide and protein pulmonary aerosol delivery. The crystalline/amorphous ratio and polymorphic form of the inorganic component was altered by changing the microparticle drying rate and by changing the ammonium carbonate and HA initial concentration. The bioactivity of the model peptide, salmon calcitonin (sCT), coprocessed with alpha-1-antitrypsin (AAT), a model protein with peptidase inhibitor activity, was maintained during processing and the microparticles had excellent aerodynamic properties, making them suitable for pulmonary aerosol delivery. The bioavailability of sCT after aerosol delivery as sCT and AAT-loaded composite microparticles to rats was 4-times higher than that of sCT solution.

  20. Health hazards due to the inhalation of amorphous silica.

    PubMed

    Merget, R; Bauer, T; Küpper, H U; Philippou, S; Bauer, H D; Breitstadt, R; Bruening, T

    2002-01-01

    Occupational exposure to crystalline silica dust is associated with an increased risk for pulmonary diseases such as silicosis, tuberculosis, chronic bronchitis, chronic obstructive pulmonary disease (COPD) and lung cancer. This review summarizes the current knowledge about the health effects of amorphous (non-crystalline) forms of silica. The major problem in the assessment of health effects of amorphous silica is its contamination with crystalline silica. This applies particularly to well-documented pneumoconiosis among diatomaceous earth workers. Intentionally manufactured synthetic amorphous silicas are without contamination of crystalline silica. These synthetic forms may be classified as (1) wet process silica, (2) pyrogenic ("thermal" or "fumed") silica, and (3) chemically or physically modified silica. According to the different physicochemical properties, the major classes of synthetic amorphous silica are used in a variety of products, e.g. as fillers in the rubber industry, in tyre compounds, as free-flow and anti-caking agents in powder materials, and as liquid carriers, particularly in the manufacture of animal feed and agrochemicals; other uses are found in toothpaste additives, paints, silicon rubber, insulation material, liquid systems in coatings, adhesives, printing inks, plastisol car undercoats, and cosmetics. Animal inhalation studies with intentionally manufactured synthetic amorphous silica showed at least partially reversible inflammation, granuloma formation and emphysema, but no progressive fibrosis of the lungs. Epidemiological studies do not support the hypothesis that amorphous silicas have any relevant potential to induce fibrosis in workers with high occupational exposure to these substances, although one study disclosed four cases with silicosis among subjects exposed to apparently non-contaminated amorphous silica. Since the data have been limited, a risk of chronic bronchitis, COPD or emphysema cannot be excluded. There is no study