This poster presentation gave an overview of the subaqueous deposition of reactive mine tailings in the open trench Don Rouyn, located near Rouyn-Noranda, Quebec. The author began by providing a brief background of subaqueous mine tailing storage, and discussed the interest of the Don Rouyn trench. The site was described according to geomorphological and geological aspects. The hydrology conditions existing at the site were mentioned, and the results of the hydrology analysis performed were indicated. Close monitoring of the situation was maintained, and the chemical and physical stability of the tailings were evaluated. The conditions that prevailed both before and after the flooding of the site were explained. Water quality is being monitored, and the results obtained at this site might be used at other locations. 40 figs.
Venomous mammals are rare, and their venoms have not been characterized. We have purified and characterized the blarina toxin (BLTX), a lethal mammalian venom with a tissue kallikrein-like activity...Full Text Available
Coal washery wastes comprise tailings finer than 0.5 to 0.1 mm depending on the sophistication of the washery, and coarse reject, typically finer than 50 mm. Subaerial disposal of coal tailings slurry at about 30% solids by mass results in the formation of a delta with an average slope of about 1 in 100, representing one extreme. The ravelling of coarse reject on loose-dumping, results in an angle of repose slope with an angle of about 37{degree} (1 in 1.3), representing the other extreme. The pumped co-disposal of coal tailings and coarse reject results in the formation of an upper delta with an average slope of about to one in ten, between the two extremes. The depositional behaviour of these three waste streams is discussed and compared. The important depositional and material parameters, and a theoretical description of the processes involved, are also presented. Comparisons are ...
The objectives of the project were (i) to develop a combination iron oxide production and carbon sequestration plant that will use serpentine ores as the source of iron and the extraction tailings as the storage element for CO2 disposal, (ii) the identification of locations within the US where this process may be implemented and (iii) to create a standardized process to characterize the serpentine deposits in terms of carbon disposal capacity and iron and steel production capacity. The first objective was not accomplished. The research failed to identify a technique to accelerate direct aqueous mineral carbonation, the limiting step in the integration of steel production and carbon sequestration. Objective (ii) was accomplished. It was found that the sequestration potential of the ultramafic resource surfaces in the US and Puerto Rico is approximately 4,647 Gt of CO2 or over 500 years of current US production of CO2. ...
Tail plates obtained from T4D amber mutants were examined with respect to sedimentation behavior, subunit molecular weights, amino acid composition, isoelectric points, and morphology. Intact plates...Full Text Available
Acid mine drainage is probably the most important problem facing the mining industry. In this study, the authors evaluated different techniques for the remediation of mine tailings. An in situ characterization of the Aldermac mine tailings was conducted and the results were presented in this poster presentation. The site characterization was performed to determine the extent of the contamination, and sampling of soils was also performed for laboratory experiments in soil covers. The authors described the methodology followed in the laboratory experiments. Chemical analysis of the leaching water was performed to determine its composition in metals. Microbiological analysis was also conducted, as well as the determination of the water saturation index. The authors indicated that they will analyze the results further. tabs., 12 figs.
Obesity is characterized by the abnormal or excessive deposition of fat in the adipose tissue. Its consequences go far beyond adverse metabolic effects on health, causing an increase in oxidative stress,...Full Text Available
Progress is reported on: radon barrier systems for uranium mill tailings; liner evaluation for uranium mill tailings; revegetation/rock cover for stabilization of inactive U-tailings sites; and application of long-term chemical biobarriers for uranium tailings.
The present analysis shows that the observed efficiency of current drive with synergy between LHCD and ICRH is in good agreement with the relativistic theory of Karney and Fisch for Landau damped waves. The predicted power absorption from the fast wave by the electron tail is within 30% of the measured value. In the presence of significant fast electron diffusion within a slowing down time it would be possible to produce central current drive using multiple ICRF resonances even when the LHCD deposition is at half radius, as in an ITER type device. (authors). 4 refs., 6 figs.
Samples from three mine tailings, the Hemlo Mine (located in Northern Ontario), the Louvicourt Mine, and the Laronde Mine (both located in Northwestern Quebec) and four different types of hydraulic binder in three different proportions (3, 4.5, 6 per cent of total dry weight of tailings) were used to prepare 33 recipes for cement caulk. The sulphur content of the three tailings is, respectively, 5 per cent, 16 per cent, and 32 per cent. Three of the four hydraulic binders are in fact a mix of two cement types: binder based on Portland cement (CP), binder based on fly ash (FA), and binder based on dross (CL). The fourth binder is based mainly on dross. The coupons of caulk dykes were flushed at 14, 28, 56, and 91 days in a humid chamber. At each of these steps, the samples were characterized for chemical, geochemical, physical, microstructural, and mechanical attributes to better understand the ...
The mining complex Eustis-Capelton, located in the Estrie, was created in 1860, just as the demand and the prices for copper were beginning to rise. It survived the economic crash that followed the end of the American Civil War and continued its activities. Mine Albert was closed in 1907, and the Capelton chemical complex in 1924. As for the Eustis Mine, it continued to operate until 1939. The various mining companies operating in the region were able to maintain their presence throughout the difficult periods due to their flexibility, their capacity to innovate and their good management practices. It was the lack of minerals and several other factors that finally contributed to the demise of the mining industry in the Estrie region. The waste rock piles and tailings at the Eustis, Albert, Capel, and Hartford Mines all display acid mine drainage potential. The tailings are located along the Eustis and Capel streams, which follow a steep course ...
Cold spray was employed as a novel low temperature approach to deposit titanium dioxide (TiO{sub 2}) photocatalytic film. The film microstructure was characterized using X-ray diffraction and scanning electron microscopy. The photocatalytic performance was examined through acetaldehyde degradation under ultraviolet illumination. Results showed that TiO{sub 2} film was successfully deposited on substrate surface through cold spray. The film thickness reached up to 15 {mu}m. The film presented a rough surface and porous structure. Owing to the low temperature of spray powder, no phase and particle size changes occurred to TiO{sub 2} during deposition. It was found that the cold-sprayed TiO{sub 2} film was active for photodegradation of acetaldehyde.
Anti-reflective coatings made with Teflon AF2400 had the highest damage thresholds recorded for physical vapor deposited coatings at the Lawrence Livermore National Laboratory damage facility. Physical vapor deposited layers of Teflon AF2400, a perfluorinated amorphous polymer, maintained the bulk optical properties of a high transmittance from 200 nm to 1600 nm, and a low refractive index. In addition, the refractive index can be intentionally reduced by control of two common deposition parameters, deposition rate and substrate temperature. Scanning electron microscopy and nuclear magnetic resonance observations indicated that morphological changes caused the variations in the refractive index rather than compositional changes. The coatings adhered to fused silica and silicon wafers under normal laboratory handling conditions.
The Rosebel gold district is hosted in a Paleoproterozoic greenstone belt of the Guiana Shield and has many characteristics that enable classification of the ores as an orogenic gold deposit. Host rocks have undergone several phases of deformation. However, gold deposition occurred late in the structural history of the belt, and is considered part of a late regional metallogenic event with respect to the geotectonic evolution of the Guiana Shield. Economic gold mineralization is hosted in felsic to mafic volcanic rocks and two sedimentary successions that are differentiated into turbiditic and arenitic depositional packages. The detailed lithostratigraphic characterization and the geochemistry enable the correlation of the local rock types with the Paramaka, the Armina, and the Rosebel for...
Time-resolved characterizations of electron beams using optical transition radiation (OTR) as a prompt conversion mechanism have recently been extended on the Los Alamos Free-electron Laser (FEL) facility 40-MeV linac. Two key timescales for rf-linac driven FELs are the micropulse (10 ps) and the macropulse (5 {mu}s to 1 ms). In the past we have used gated, intensified cameras to select a single or few micropulses (25 to 400 ns gate width) out of the pulse train to evaluate submacropulse effects. Recently, we have obtained some of the first measurements of micropulse bunch length (7 to 10 ps) and submacropulse spatial position and profile using OTR and a Hamamatsu streak camera. Additionally, micropulse elongation effects and head-to-tail transverse kicks are reported as a function of charge.
Time-resolved characterizations of electron beams using optical transition radiation (OTR) as a prompt conversion mechanism have recently been extended on the Los Alamos Free-electron Laser (FEL) facility 40-MeV linac. Two key timescales for rf-linac driven FELs are the micropulse (10 ps) and the macropulse (5 {mu}s to 1 ms). In the past we have used gated, intensified cameras to select a single or few micropulses (25 to 400 ns gate width) out of the pulse train to evaluate submacropulse effects. Recently, we have obtained some of the first measurements of micropulse bunch length (7 to 10 ps) and submacropulse spatial position and profile using OTR and a Hamamatsu streak camera. Additionally, micropulse elongation effects and head-to-tail transverse kicks are reported as a function of charge.
This paper reports the use of molecular methods to characterize the coprophilous fungal communities (CFC) that inhabit the dung of four species of mammalian herbivores at two sites, Sevilleta National Wildlife Refuge (SNWR) in New Mexico and Wind Cave National Park (WCNP) in South Dakota. Results reveal that CFC from domesticated cattle (Bos taurus) at SNWR, and bison (Bison bison) and black-tailed prairie dogs (Cynomys ludovicianus) at WCNP were diverse but dominated primarily by members within eight taxonomic orders, including the rarely cultured and anaerobic order Neocallimastigales. In addition, 7.7% (138 of 1,788) of the sequences obtained from all dung samples were at least 97% similar to root-associated fungal (RAF) sequences previously described from blue grama (Bouteloua gracilis...
Time-resolved characterizations of electron beams using optical transition radiation (OTR) as a prompt conversion mechanism have recently been extended on the Los Alamos Free-electron Laser (FEL) facility 40-MeV linac. Two key timescales for rf-linac driven FELs are the micropulse (10 ps) and the macropulse (5 [mu]s to 1 ms). In the past we have used gated, intensified cameras to select a single or few micropulses (25 to 400 ns gate width) out of the pulse train to evaluate submacropulse effects. Recently, we have obtained some of the first measurements of micropulse bunch length (7 to 10 ps) and submacropulse spatialposition and profile using OTR and a Hamamatsu streak camera. Additionally, micropulse elongation effects and head-to-tail transverse kick effects are reported as a function of charge.
Time-resolved characterizations of electron beams using optical transition radiation (OTR) as a prompt conversion mechanism have recently been extended on the Los Alamos Free-electron Laser (FEL) facility 40-MeV linac. Two key timescales for rf-linac driven FELs are the micropulse (10 ps) and the macropulse (5 {mu}s to 1 ms). In the past we have used gated, intensified cameras to select a single or few micropulses (25 to 400 ns gate width) out of the pulse train to evaluate submacropulse effects. Recently, we have obtained some of the first measurements of micropulse bunch length (7 to 10 ps) and submacropulse spatialposition and profile using OTR and a Hamamatsu streak camera. Additionally, micropulse elongation effects and head-to-tail transverse kick effects are reported as a function of charge.
Discusses results of investigations into catalytic properties of various minerals during hydrogenation of Kansk-Achinsk brown coal with a view to replacing synthetic compositions based on molybdenum. Describes tests and equipment used in hydrogenation of grade B-2 Borodinsk deposit coal in tetralin (hydrogen donor). Various by-products of metallurgical processes and compounds separated from tailings containing mainly iron and sulfur and other metals were used as catalysts. States that: minerals containing iron compounds in the form of pyrites, hematites and magnetites exhibit catalytic properties when used in the hydrogenation of brown coal; pyritic catalysts enrich liquid products with hydrogen while sulfur and nitrogen content remains the same; the yield of malthenes with pyritic catalysts is no lower than with alumocobaltmolybdenum catalysts. 18 refs.
Perylene bisimides (PBIs) represent an important class of organic n-type semiconductors exhibiting a relatively high electron affinity among large-band-gap materials. Herein synthesis and characterization of several unsymmetrical N-substituted PBI dyes is presented and the thermotropic behavior, which is strongly affected by the respective N-substituents was investigated. Two different series of highly soluble and fluorescent derivatives have been synthesized: (1) PBIs bearing swallow-tailed alkyl chains, different in size or (2) one swallow-tailed alkyl chain and one branched oligoethylenglycolether. Synthesis of these PBIs is generally feasible by two distinct divergent synthesis approaches. Thermotropic behavior was studied by DSC, POM and XRD measurements. Inherent {pi}-{pi} interactions between cofacially orientated perylene molecules and the elliptic shape of the molecule favor the ordering in columns and ...
Focused Ion Beam (FIB) repairs and modifications to integrated circuits have been somewhat limited in the past due to the physical limitations imposed by the nodes of interest being buried under metal layers, the need for multiple layers of FIB generated interconnects, and the like. With the advent of FIB deposited INSULATOR materials, integrated circuit modifications can now be much more complex. The two primary goals of this project were (1) to determine the appropriateness of FIB insulator deposition for aiding FIB connections to metal nodes buried under power busses, and (2) development of a technique to do this. The work presented in this paper includes the development and characterization phases of adding INSULATION DEPOSITION to a FEI 611 FIB system, the problems encountered, their work around, and the aforementioned application of this technology.
Many mines and processing facilities are in remote, difficult to access areas, or are in areas where access is limited or restricted for national reasons. In a joint project with Canada Centre for Remote Sensing, the Canadian Safeguards Support Program is investigating utility of multi- and hyperspectral remote sensing for remotely inspecting such site. With a view to eventually using the hyperspectral satellite data now coming available, airborne data over uranium and copper mine tailings and uranium processing facilities in northern Canada were acquired. The objective of this work is to demonstrate that multispectral and hyperspectral data can provide complementary and supplementary information to high-resolution panchromatic imagery for the following safeguards applications: Inspection aids (up-to-date maps of remote locations), change detection, evaluation of member state declarations, monitoring of reactor, mining and processing facility operations, and ...
For a given linac design, the dosimetric characteristics of a photon beam are determined uniquely by the energy and radial distributions of the electron beam striking the x-ray target. However, in the usual commissioning of a beam from measured data, a large number of variables can be independently tuned, making it difficult to derive a unique and self-consistent beam model. For example, the measured dosimetric penumbra in water may be attributed in various proportions to the lateral secondary electron range, the focal spot size and the transmission through the tips of a non-divergent collimator; the head-scatter component in the tails of the transverse profiles may not be easy to resolve from phantom scatter and head leakage; and the head-scatter tails corresponding to a certain extra-focal source model may not agree self-consistently with in-air output factors measured on the central axis. To reduce the number of adjustable variables in beam ...
The properties of polycrystalline (Ti, Al)N coatings deposited on non-nitrided, classically plasma-nitrided and low pressure plasma-nitrided AISI H11 steel samples were investigated. The plasma deposition and low pressure plasma nitriding were performed in a Z700-LH magnetron sputter ion plating unit, while a separate unit was used for plasma nitriding of specimens at a pressure of several millibars. The (Ti, Al)N coating was deposited onto all the samples using the same equipment as for the plasma deposition and low pressure plasma nitriding. For the characterization of the composite structures, the following methods were used: scratch test, X-ray diffraction analysis, scanning electron microscopy, scanning tunnelling microscopy and microhardness testing. It was found that plasma nitriding prior to coating deposition strongly affects the growth and properties ...
Models of the human airways have played a major role in evaluating the health effects of inhaled radionuclides. While models such as those of Weibel (1963) provide data necessary for characterizingdeposition of aerosol, they have not characterized the cells at risks in the airspaces. Given the advancements in techniques and study of cell cultures exposed to ionizing radiation there is a need to extrapolate between the simple structures of cell culture systems and the complex architecture of the human airways. The preliminary data in this paper provide a complete characterization of the size and number of cells in the airways and represents a significant advance in our study of the health consequences of exposure to inhaled radionuclides. 26 refs., 2 figs., 4 tabs.
Objective of the project is characterization of electrode reactions in molten salt by using metal oxides and silica-based electrode. The scope of project are characterization of metal oxide properties in molten salt and miniaturization of 3-electrode electrochemical test cell. Electrochemical micro-cell for actinide-LiCl-KCl molten salt was newly designed. Electroless and electrochemical deposition technique was applied to Mo coating on quartz tube. From the design of electrode and 3-electrode electrochemical cell suitable for the tests in molten salt electrolyte, so it is anticipated to get the information on the electrochemical behavior of metallic electrode in molten salt and to secure the information on oxidation/reduction behavior of actinide
N-ethyl-N-nitrosourea (ENU) mutagenesis has led to the elucidation of several regulator genes for melanocyte and skin development. Here we characterized a mutant from ENU mutagenesis with similar phenotype as that of Splotch mutant, including exencephaly, spina bifida and abnormal limbs in homozygotes as well as white belly spotting and occasionally loop-tail in heterozygotes. This novel mutant was named as Sp(xG). Through genome-wide linkage analysis in backcross progenies with microsatellite markers, the Sp(xG) was confined to a region between D1MIT415 and D1MIT7 on chromosome 1, where notable Pax3 gene was located. Direct sequencing revealed that Sp(xG) carried a nucleotide A894G missense transition in exon 6 of Pax3 gene that resulted in Asn to Asp substitution at amino acid 269 within the highly-conserved homeodomain (HD) DNA recognition module, which was the first point mutation found in this domain in mice. This N269D mutation impaired ...
Mining of copper and zinc took place at the Clinton Mine located in the Estrie region of Quebec between 1973 and 1975, during which time 115,000 tons of mineral were treated at the Solbec plant. In this poster presentation, the authors provided the background information pertaining to this mine and described the state in which it was in 1994. The pit was covered with good quality water, with a pH of 7,1 and copper and zinc content ranging between 0,1 and 0,6 mg/l, and iron ranging between 0,2 and 1,8 mg/l. The tailings basin drainage was found to have a pH of between 3,6 and 6,1. A program for the characterization of the site was implemented and the concept for the restauration of the Clinton site was developed and implemented. The work carried out at the site is discussed during this presentation as well as the monitoring taking place. 27 figs.
The authors have cloned and determined the entire nucleotide sequence of cDNAs corresponding to the putative {alpha} subunits of the human and rat mast cell high-affinity IgE receptors. Both human and rat cDNAs encode an NH{sub 2}-terminal signal peptide, two immunoglobulin-like extracellular domains (encoded by discrete exons), a hydrophobic transmembrane region, and a positively charged cytoplasmic tail. The human and rat {alpha} subunits share an overall homology with one another and the immunoglobulin gene family, suggesting that they arose from a common ancestral gene and continue to share structural homology with their ligands. In addition, the rat gene is transcribed into at least three distinct forms, each of which yields a somewhat different coding sequence.
The coherent flucton model is applied to the description of some basic nuclear properties, such as: ground state energies, bond energies, nucleon momentum spectra, and nuclear density distributions. It is shown that the momentum distributions of the nucleons coincide with the Fermi distribution for small momenta and exhibit a well pronounced high energy ''tail'', thus providing inclusive reactions of pi-meson generations in kinematically forbidden areas at nucleon-nucleon collisions. Analytical expressions for the bond energy and nuclear density distribution are derived. An agreement with the experimentally obtained data is achieved. The model features are discussed referring to the processes, characterized mainly by the geometric and dynamic properties of the nuclei, as well as by nuclear density distribution. In particular, ion-ion scattering processes at high energy are considered.
The coherent flucton model is applied to the description of some basic nuclear properties, such as: ground state energies, bond energies, nucleon momentum spectra, and nuclear density distributions. It is shown that the momentum distributions of the nucleons coincide with the Fermi distribution for small momenta and exhibit a well pronounced high energy ''tail'', thus providing inclusive reactions of pi-meson generations in kinematically forbidden areas at nucleon-nucleon collisions. Analytical expressions for the bond energy and nuclear density distribution are derived. An agreement with the experimentally obtained data is achieved. The model features are discussed referring to the processes, characterized mainly by the geometric and dynamic properties of the nuclei, as well as by nuclear density distribution. In particular, ion-ion scattering processes at high energy are considered.
Iron oxide thin films have been obtained by spray pyrolysis using 100% methanolic and ethanolic solutions of iron tri-chloride. The films were deposited onto ITO-coated glass substrates. The preparative conditions have been optimized to obtain compact, pin-hole-free and smooth thin films which are adherent to the substrate. The structural, morphological and compositional characterizations have been carried out by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. The films deposited using ethanolic solution results into pure hematite; #alpha#-Fe_2O_3 thin films, however, films deposited using methanolic solution consists of hematite and maghemite-c phases of iron oxide. The films are nanocrystalline with particle size of 30-40 nm. The optical absorbance of the film was of the order of 10"5 cm"-"1. The optical band gap of films was found to be 2.26 and 2.20 eV for the ...
Magnetic materials such as yttrium iron garnet (YIG) are of great importance for its magneto-optic properties and for their potential applications in the domain of optical telecommunications. The deposition of thin films of YIG, on quartz or GGG (gadolinium gallium garnet) substrate, was performed using radio frequency non reactive magnetron sputtering, followed by high temperature annealing which is needed to enhance the crystallinity of the layers. Rutherford backscattering spectrometry RBS was used to determine the thickness and stoichiometry of the performed layers in order to investigate correlations between growth conditions and the quality of the final material. RBS measurements showed the influence of the deposition time and the temperature substrate on the film growth and its stoichiometry. (author)
The microstructure, microhardness, corrosion, and wear resistance of d.c.-plated Ni electrodeposits prepared from different types of electrolysing Watts-type baths, without or with organic compounds, ceramic powder - SiC and polymer - polytetrafluoroethylene (PTFE), on Cu substrate, which was subsequently removed from the deposits, were investigated. With the change of the type of bath, the deposit grain size was found to decrease markedly, e.g. deposits with an average grain size of about 50 nm could be produced from the bath containing 45 g/dm"3 Ni"2"+ ions, 5 g/dm"3 SiC, and 20 g/dm"3 PTFE. The surface morphology on the bath side of the electrode-posited Ni or Ni-SiC-PTFE foils was characteristic of the type of bath, and its roughness correlated well with the observed grain size. Microhardness and wear resistance increased with decreasing grain size, as expected. On discussing the factors controlling ...
Iron oxide films have been deposited on Si(100) substrates by chemical vapour deposition (CVD) of iron(III) tert-butoxide ([Fe(O "tBu)_3]_2) in the temperature range 350-450 deg. C. The precursor flux and substrate temperature were varied to control the phase composition, average grain size and film thickness. The nature of substrate and deposition temperature markedly influence the morphology and iron-oxygen stoichiometry in the CVD deposits. Phase transformations in iron oxide films were achieved through precise local and periodic heating of the films by interfering laser beams. The interaction of iron oxide films with short laser pulses (Nd:YAG, 355 nm) induced partial transformation of hematite (#alpha#-Fe_2O_3) to magnetite (Fe_3O_4) or magnetite to wuestite (Fe_1_-_xO), respectively. The phase characterization and morphology of the hematite and magnetite films were ...
In this work we present an ultra-low temperature method for the oxidation of an amorphous silicon-carbide-nitride (SiCN) material. The SiCN is deposited on silicon substrates by plasma enhanced chemical vapor deposition using CH{sub 4}, SiH{sub 4}, and N{sub 2} chemistry. The physical and chemical properties are characterized for the as-deposited SiCN and post-oxidized films are discussed. The SiCN film is exposed to oxygen plasma, where it undergoes a chemical transformation into a binary SiO{sub 2} material system. A 1.7 nm/min oxidation rate is typical for this process and compares favorably to oxidation methods utilizing much higher temperatures. The substrate temperature remains extremely low throughout the oxidation process, T{sub s} < 200 deg. C. Changes in film stress, optical constants, film thickness, surface roughness, and film density are measured. Chemical analysis by X-ray ...
Indium sulfide thin films consisting of porous network of nanoplatelets, have been deposited using chemical bath deposition (CBD) method onto the tin-doped indium oxide (ITO) coated glass substrate. Aqueous solutions of indium sulfate and thioacetamide have been used as indium and sulfur precursors. As a complexing agent, acetic acid was used. The chemically deposited indium sulfide thin films were examined for their structural, surface morphological and optical characterizations. The X-ray diffraction analysis revealed the formation of the cubic b-In2S3 onto the substrate. From scanning electron micrograph, it is observed that the surface of substrate is covered by nanoporous platelets type morphology. The optical studies showed a direct band gap of 2.84eV for indium sulfide platelets. Ph...
In boron mining and processing operations, large amounts of clay containing tailings have to be discarded. Being rich in boron, the tailings do not only cause economical loss but also pose serious environmental problems. Large areas have to be allocated for waste disposal. In order to alleviate this problem, the possibility of using clayey tailings from a borax concentrator in red brick manufacturing was investigated. Up to 30% by weight tailings addition was found to improve the brick quality.
Ketamine-anesthetized Sprague-Dawley rats were exposed to far-field 700-MHz continuous-wave radiofrequency radiation (RFR) in both E and H orientations. Irradiation was conducted at whole-body average specific absorption rates (SARs) of 9.2 and 13.0 W/kg (E and H, respectively) that resulted in approximately equivalent colonic specific heating rates (SHRs). Exposures were performed to repeatedly increase colonic temperature by 1 deg C (38.5 to 39.5 deg C). Tympanic, tail, left and right subcutaneous (toward and away from RFR source), and colonic temperatures, arterial blood pressure, and respiratory rate were continuously recorded. In spite of equivalent colonic SHRs and the reduced E-orientation average SAR, the right subcutaneous, tympanic, and tail SARs, SHRs and absolute temperature increases were significantly greater in E than in H orientation. The cooling rate at all monitoring sites was also significantly greater in E than in H ...
Full text: Mt Morgan was mined for copper and gold from 1882 to 1982 and subsequent tailings re-processing ceased in 1990. Direct and accidental deposition of tailings into the adjacent Dee River and acid mine drainage from the mine site continues to impact the Dee River. The Queensland Department of Natural Resources gauging and monitoring station at Kenbula (adjacent to the mine) continuously monitors pH of around 2.8. Twenty kilometres downstream of the mine the pH improves to 3.5. Elevated sediment metal concentrations have been recorded over 50 kilometres downstream in investigations conducted by CSIRO (Jones et al. 1995, 1996) and others. Biological monitoring by Mackey (1988) and subsequently by Duivendoorden (1995,1997), confirmed significant impact on the fish, macrophyte of macro invertebrate populations downstream of the mine. The current AINSE sponsored project will investigate the use of mussels (genus ...
The Buntsandstein facies outcrops along a 12 km long, 150 m thick cuesta near Ayllon (Central Spain). The outcrop study is based on vertical sedimentological sections and continuous photo paneling, and demonstrates the presence of two depositional systems: an alluvial fan system in the lower half of the outcrop, and a straight and braided river system in the upper part of the outcrop. This overall evolution is probably related to base-level fall to base-level rise cycle, in which the reservoir architecture is linked to genetic units stacking pattern: during the base-level fall, the alluvial fan is prograding over sand flat and sandy alluvial plain deposits. Coarse and pebbly proximal sandsheets are interbedded with finer reddish distal deposits. Reservoirs units are laterally continuous, but silty alluvial plain deposits constitute vertical permeability barriers, during base-level stillstand, erosive ...
Abstract P/2004 A1 (LONEOS) is one of the few active objects in the dynamical class of Centaurs. It has been recently injected into an inner orbit with a perihelion distance-q-= 5.5 au. The aim of this paper is to characterize the dust coma of this peculiar object, 2.5 yr after its first -new- perihelion passage inside the Solar system. Broad-band visible images taken at the TNG telescope in 2007 February were analysed in order to characterize the dust coma of the Centaur: it was still quite active at-rh-= 6.5 au post-perihelion, with a coma and a well-developed wide tail-like structure, with a measured-R-Af= 162 10-cm in an aperture radius = 104 km. The (V---R) colour and the reddening values depict a scenario of a slightly red dust coma. A dust mass-loss rate of--= 133 kg-s-1 is derived ...
We tried to apply a quartz crystal as a sensor by using the resonant frequency and the resistance properties of quartz crystals. Four kinds of fatty acids that have the same head groups were coated on the surfaces of the quartz crystals, and the shift of the resonant frequency and the resistance were observed based on the lengths of the tail groups. Myristic acid (C{sub 14}), palmitic acid (C{sub 16}), stearic acid (C{sub 18}), and arachidic acid (C{sub 20}) were deposited on the surfaces of quartz crystals by using the Langmuir-Blodgett (LB) method. As a result, the resonant frequency change was more sensitive to high molecular-weight fatty acids than to low molecular-weight ones. We also observed the effect of temperature on stearic acid LB films, and the response properties of quartz crystals coated with stearic-acid LB films to organic gases were investigated. As a result, the sensitivity of quartz crystals to organic gases was higher for ...
Focused ion beam (FIB) irradiation of a thin Ni_2Si layer deposited on a Si substrate was carried out and studied using an in-situ transmission electron microscope (in-situ TEM). Square areas on sides of 4 by 4 and 9 by 9 microm were patterned at room temperature with a 25 keV Ga"+-FIB attached to the TEM. The structural changes of the films indicate a uniform milling, sputtering of the Ni_2Si layer and the damage introducing to the Si substrate. Annealing at 673 K results in the change of the Ni_2Si layer into an epitaxial NiSi_2 layer outside the FIB irradiated area, but several precipitates appear around the treated area. Precipitates was analyzed by energy dispersive X-ray spectroscopy (EDS). Larger amount of Ni than the surrounding matrix was found in precipitates. Selected area diffraction (SAD) patterns of the precipitates and the corresponding dark field images imply the formation of a Ni rich silicide. The relation between the FIB tail ...
Thorium-230, together with "2"3"8U and "2"2"6Ra, was determined (mainly by #gamma#-spectrometry) in samples from the waste piles at Borst and Jazbec in the vicinity of the former uranium mine at Zirovski vrh, Slovenia. Activity (and in the case of uranium, also mass) balances for these nuclides were constructed for the overall operation of the mine and yellow cake plant, using experimental data and known data on ore and uranium production, and nuclide emissions to the environment. All the "2"2"6Ra resulting from ore exploitation is presently contained in the Borst tailings pile. However, because of the very high content of "2"3"0Th in red mud deposited at Jazbec, where 60% of this nuclide is found, the majority of "2"2"6Ra will be found at the Jazbec pile in the future, due to its ingrowth from "2"3"0Th over the next few thousand years. (Author).
Microstructure and electrical properties of iron oxide Fe_2O_3 thin films prepared by spray pyrolysis method have been experimentally characterized. The effect of substrate temperature as well as deposition time on the structural features (crystallite size and microstrain) and electric resistivity of these films has been investigated. X-ray diffraction (XRD) and scanning electron microscope (SEM) characterized the structure study. The results of X-ray diffraction showed that with increasing substrate temperature bias the film structure changed from amorphous to crystalline at the same deposition time. At a substrate temperature of 350 deg. C and low deposition time, #alpha#-Fe_2O_3 appears almost in amorphous form. With rising the substrate temperature and deposition time, the crystallinity was improved. At T_s_u_b>350 deg. C, a well-crystallized rhombohedral ...
A research program has been undertaken to characterize oil sand deposits. Studies include delination of reservoir architecture; petrophysical attributes; and petrography and core analysis.
The part of the FFTF Reactor Characterization Program reported in this paper is a measurement of absolute fission rates of eight major fuel isotopes at two different positions within the reactor. The instruments employed in these tests were fission ionization chambers for which the absolute efficiency and fissionable deposit mass assay have been rigorously established.
Laser-assisted processing techniques for producing high-quality solar cell metallization patterns are being investigated, developed, and characterized. A literature search was carried out on the various state-of-the-art laser-assisted techniques for metal deposition, including laser chemical vapor deposition and laser photolysis of organometallics, as well as laser-enhanced electroplating. The results of the literature survey are briefly summarized. Experiments were carried out on laser-enhanced electroplating. Deposition of metals by laser-assisted pyrolysis of a variety of metallo-organic inks and metal-bearing polymer solutions spun as films onto silicon wafers was carried out. A detailed study of the various models of localized surface temperature rise in silicon due to laser heating has been carried out. Progress is reported in fabricating laser-metallized solar cells with improved efficiencies. ...
A one-nanometer scale transmission electron microscope electron probe X-ray microanalysis characterization of as-deposited and annealed aluminum--11.5 at.% zirconium multilayer samples in cross-section synthesized by magnetron sputtering is reported on here. Composition line profiles were acquired across Zr layers in as-deposited material and samples isochronally annealed in a differential scanning calorimeter to temperatures of 290 C and 485 C. A spatial resolution of approximately 1.5 to 2.0 nm was achieved in these experiments and will be improved by deconvolution of the instrumental electron probe function from the data. The as-deposited structure consisted of crystalline Al and Zr layers with thin amorphous layers at the Al/Zr interfaces. The amorphous interface layers increased in thickness upon annealing to 290 C. Additionally, at 290 C a metastable cubic alloy forms at the Zr ...
In this work, amorphous hydrocarbon (a-C:H) film deposition on metallic mirrors was studied during working shots in tokamak T-10 and at exposure in Ar/CHD3/D2 dc magnetron discharge in a special laboratory high vacuum setup. Analysis of film composition (including hydrogen content) was carried out using nuclear physical methods. Thickness and optical parameters (refractive and extinction coefficients) of the films were estimated by ellipsometry. Laboratory films can be characterized as soft a-C:H films in comparison with hard tokamak films (? = 1.2 and 1.8 g/cm3, respectively). For the first one, a linear dependence of deposition rate on mirror temperature was observed in a wide temperature range. The addition of methane into initial Ar/D2 magnetron gas mixture leads to an increase of deposition rate. The data obtained should be taken into account to prevent hydrocarbon film formation on the surface of ...
The initiation and characteristics of mossy zinc electrodeposits have been investigated. Batteries with zinc electrodes are candidates for electric vehicle applications; however, this electrode is prone to form non-compact deposits that contribute to capacity loss and battery failure. Moss is deposited when the current density is far from the limiting current. This morphology first appears only after the bulk deposit is approximately 1 {mu}m thick. In this investigation, the effects of flow rate (Re=0--4000), current density (0--50 mA/cm{sup 2}), concentration of the electroactive species (0.25 and 0.5 M), and the concentration of supporting electrolyte (3, 6, and 12 M) on the initiation of moss were examined. The rotating concentric cylinder electrode was employed for most of the experiments; and a flow channel was used to study the development of morphology. After the experiment, the deposit was ...
Chitosan (Ch) microspheres have been developed by precipitation method, cross-linked with glutaraldehyde and used as a template for layer-by-layer (LBL) deposition of two natural polyelectrolytes. Using a LBL methodology, Ch microspheres were alternately coated with hyaluronic acid (HA) and Ch under mild conditions. The roughness of the Ch-based crosslinked microspheres was characterized by atomic force microscopy (AFM). Morphological characterization was performed by environmental scanning electron microscopy (ESEM), scanning electron microscopy (SEM) and stereolight microscopy. The swelling behaviour of the microspheres demonstrated that the ones with more bilayers presented the highest water uptake and the uncoated cross-linked Ch microspheres showed the lowest uptake capability. Micros...
The meeting featured seven sessions with 18 papers abstracted/indexed therein as follows: keynote address: tailings dams safety - implications for the dam safety community; 1 - design and performance: performance monitoring of dams: are we doing what we should be doing?; tailings dams from the perspective of conventional dam engineering; and design overview of Syncrude's Mildred Lake east toe berm; 2 - design and modelling: use of a 2D model for a dam break study on the ALCAN hydroelectric complex in Quebec; and spillway design implications resulting from changes in rainfall extremes; 3 - risk and dam safety I: closing the gaps in the dam safety guidelines; the reality of life safety consequence classification; and surveillance practices for the next millenium; 4 - risk and dam safety II: quantitative risk-assessment using the capacity-demand analysis; and new guidelines for dam safety classification; 5 - millenium issues: expectations ...
Basic research of the structure and electronic properties of a-Si:H is reported with particular emphasis on the role of defects. The main findings are as follows: (1) low defect density material can be deposited at a high rate using SiH/sub 4/ diluted in He or Ne. Using Ar or Kr results in a high defect density and columnar material; (2) an electrical bias during deposition modifies the band gap, hydrogen concentration and structure; (3) the clustering of hydrogen in the regions between the columns is confirmed; (4) hydrogen diffusion is observed by NMR; (5) the oxidation of an a-Si:H surface results in approx. 3 x 10/sup 11/ cm/sup -2/ dangling bonds at the interface; (6) auger recombination of photoexcited carriers is a significant non-radiative mechanism at low temperatures; (7) non-radiative recombination by diffusion and capture at dangling bonds is observed at temperatures above 50 to 100/sup 0/K; (8) the defect density in doped and ...
We have studied in detail the gamma radiation induced changes in the electrical properties of the (TeO_2)_0_._9 (In_2O_3)_0 _._1 thin films of different thicknesses, prepared by thermal evaporation in vacuum. The current-voltage characteristics for the as-deposited and exposed thin films were analysed to obtain current versus dose plots at different applied voltages. These plots clearly show that the current increases quite linearly with the radiation dose over a wide range and that the range of doses is higher for the thicker films. Beyond certain dose (a quantity dependent on the film thickness), however, the current has been observed to decrease. In order to understand the dose dependence of the current, we analysed the optical absorption spectra for the as-deposited and exposed thin films to obtain the dose dependences of the optical bandgap and energy width of band tails of the localized states. The increase of the ...
Six related Staphylococcus phages spontaneously produced various abnormal head and tail structures: (i) giant capsids which were tailed and apparently contained nucleic acid; (ii) regular and irregular...Full Text Available
This report presents geologic considerations that are pertinent to the Remedial Action Plan for Slick Rock mill tailings. Topics covered include regional geology, site geology, geologic stability, and geologic suitability.
A strain of Chromobacterium violaceum has been isolated which produces bacteriophage tail-like particles in high numbers. The extracellular morphology and the intracellular arrangement...Full Text Available
The proportion of energy absorbed by the tail of a rat carcass was determined. Male (288 g - 457 g) and female (195 g - 249 g) Sprague-Dawley rat carcasses were exposed to far-field, continuous-wave radiofrequency radiation (RFR). The carcasses were split into two mixed groups: one group was exposed to 700-MHz RFR; and the other, to 350-MHz RFR. Immediately after each exposure, the tail was severed, and the specific absorption rates (SAR) of the tail and body were determined by Dewar flask calorimetry. For example, a 195 g female exposed to 700 MHz yielded SARs of 1.26 and 3.64 mW/g (normalized to 1 nW/cm2 incident power density) for its body and tail, respectively; the tail contributed 6.7% to the total energy absorption. For a 205 g female exposed to 350 MHz, however, the tail contributed 19.0% to the whole-body absorption. Normalized SARs of 0.40 and 4.03 ...
BackgroundIt has been assumed that the unusual tail club of ankylosaurid dinosaurs was used actively as a weapon, but the biological feasibility of this behaviour has not been examined...Full Text Available
The influence of selenium dioxide (SeO2) on the microstructure and electrodeposition of manganese coatings obtained from a sulfate based neutral solution was investigated by material characterization methods and electrochemical techniques. The crystal structure and surface morphology of these coatings were studied by scanning electron microscopy (SEM) and powder X-ray diffraction spectroscopy (XRD), respectively. The SEM and XRD data showed that SeO2 could effectively accelerate phase transformation, and facilitate leveled and fine grain growth. The electrochemical results indicated that SeO2 could inhibit hydrogen evolution reaction and promote manganese deposition. The action of selenium dioxide in manganese deposition was found to be a reduction and adsorption mechanism. The process cou...
In this paper, we study the optical properties of indium sulfide thin films to establish the best conditions to obtain a good solar cell buffer layer. The In2S3 buffer layers have been prepared by chemical bath deposition (CBD) and thermal evaporation (PVD). Optical behavior differences have been found between CBD and PVD In2S3 thin films that have been explained as due to structural, morphological and compositional differences observed in the films prepared by both methods. The resultant refractive index difference has to be attributed to the lower density of the CBD films, which can be related to the presence of oxygen. Its higher refractive index makes PVD film better suited to reduce overall reflectance in a typical CIGS solar cell.
Low-temperature polysilicon thin-film transistors (TFT's) have been fabricated from sputtered silicon films and characterized as a function of as-deposited hydrogen (H) content and laser crystallization fluence. A general trend is observed where TFT performance improves as the H content is lowered. Devices made from {approximately}0% H sputtered films perform similar to those made from low-pressure chemical-vapor deposition processes (LPCVD), but are fabricated at a much lower process temperature (300 C). The best sputtered TFT's had mobilities of {approximately}200 cm{sup 2}/Vs, and on/off current ratios of more than 10{sup 8}.
Silicon layered structures containing porous silicon modified with various thermal treatments and epitaxial layers deposited on porous layers were studied with a number of complementary X-ray diffraction methods using synchrotron source. The methods of characterization included recording of rocking curves for reflections with various asymmetry as well as projection, section and micro-Laue topography. It was found that oxidizing and sintering of porous silicon seriously modified the strains in the porous layer and in some cases even inverting the sense of strain with respect to that in initially formed porous layer. Consequently the deposited epitaxial layer usually was not laterally coherent with the substrate. Some of investigated layers were not stable in time and after few months period exhibited significant lost of coherence of porous skeleton. (author)
Chromium nitride thin films were deposited on SA-304 stainless steel substrates by using direct-current reactive magnetron sputtering. The influence of process conditions such as nitrogen content in the fed gas, substrate temperature, and different sputtering gases on microstructural characteristics of the films was investigated. The films showed (200) preferred orientation at low nitrogen content (< 30%) in the fed gas. The formation of Cr_2N and CrN phases was observed when 30% and 40% N_2 were used, with a balance of Ar, respectively. Field emission scanning electron microscopy and atomic force microscopy were used to characterize the morphology and surface topography of the thin films, respectively. Microhardness tests showed a maximum hardness of 16.95 GPa for the 30% nitrogen content.
The erosion of rocks rich in organic matter typically leads to the complete mineralization of the organic material. However, in some cases, it is re-deposited to become a part of sediments once more. This process should be considered to be a part of global carbon cycle, possibly much more significant than assumed to-date. The research presented here aims to characterize re-worked organic matter occurring in post-glacial sediments of southern part of Poland, in the Oder river valley (the Racib?rz town region, Miocene, Pleistocene and Holocene age). Organic substances extracted from the sediments originated from organic matter that had resided in rocks eroded by glaciers. Sediments were sampled in two boreholes which sediments were correlated. Sediments were extracted and extracts analyzed w...
Amino-rich polymeric coatings are widely used in biomedical applications, since they promote adsorption of diverse biomolecules or facilitate cell growth. As a consequence, there is a growing interest in fabrication of such coatings that is focused predominantly on the optimization of the deposition process in terms of high density of primary amino groups. In addition, the nature of biomedical applications requires also sufficient stability of the films in aqueous environments. This aspect is investigated in this contribution. In particular, the effect of water and phosphate buffer saline on the coatings prepared by RF magnetron sputtering of Nylon 6,6 in Ar/N2 and N2/H2 gas mixtures is evaluated. The samples exposed to liquids are characterized by various diagnostic methods and their prop...
The combined processes of plasma nitriding and cathodic arc deposition of (Ti,Cr,Nb)CN coatings were applied to HSS substrates. The nitrided layers, obtained in a mixture of H2 (70%) and N2 (30%) at two different temperatures (480^oC and 510^oC), were examined for the microhardness depth profiles. Characterization of the duplex coatings was performed by investigating elemental and phase composition, texture, hardness, friction and wear. XRD and XPS analyses revealed the formation of a mixture of a carbonitride fcc solid solution, in a dominant proportion, and metallic chromium. The film hardness was measured to be ~34GPa. The duplex (Ti,Cr,Nb)CN coatings exhibited superior tribological behavior as compared to both nitrided layers and non-duplex coatings.
Detailed investigations of geologic, geomorphic, and seismic conditions at the Bodo Canyon disposal site were conducted. The purpose of these investigations was basic site characterization and identification of potential geologic hazards that could affect long-term site stability. Subsequent engineering studies, such as analyses of hydrologic and liquefaction hazards, used the data developed in these studies. The geomorphic analysis was employed in the design of effective erosion protection. Studies of the regional and local seismotectonic setting, which included a detailed search for possible capable faults within a 65 kilometer radius of the site, provided the basis for seismic design parameters. The scope of work performed included the following: Compilation and analysis of previous published and unpublished geologic literature and maps; Review of historical and instrumental earthquake data; Review of site-specific subsurface geologic data, including lithologic ...
A high sensitivity (titer 60-150,000) radioimmunoassay for arginine vasopressin (AVP) has been developed using synthetic AVP as antigen and standard. The specificity of the antiserum has been characterized in detail by measuring the relative binding affinities of 29 analogs and fragments of AVP. In general, single amino acid substitution or deletion in the AVP molecule caused a reduction in binding to the antiserum; binding was further impaired for analogs which had multiple substitutions. ''Ring'' and ''tail'' fragments of the neurohypophysial hormones did not bind to the antiserum, and the only analog which the antiserum could not differentiate from AVP was deamino-AVP. More specifically, the antiserum exhibited the following properties: position 1, no requirement for a position charge at "1/_2 Cys; positions 2 and 3, requirements for #pi#-#pi# interacting pair of aromatic side chains and for Tyr at position 2; position 4, requirement for Gln ...
Catalase is an important antioxidant protein which can protect organisms against various oxidative stresses by eliminating hydrogen peroxide. The catalase cDNA of Cristaria plicata@?cpCAT@? was cloned from the haemocytes using degenerate primers by the method of 3' and 5' rapid amplification of cDNA ends PCR. The gene is 4863 bp long and has a total of two introns and three exons. The precise size and location of the introns and exons have been determined. In addition the full-length cDNA of cpCAT contained 2618 bp, The cDNA contained a 5' untranslated region (UTR) of 136 nucleotides, the 3' UTR of 979 bp with a canonical polyadenylation signal sequence AATAAA and a polyA tail, and an open reading frame (ORF) of 1503 bp, encoding 501 amino acid residues with 56.86 kDa predicted molecular w...
The aim of this contract is to investigate, develop, and characterize laser-assisted processing techniques utilized to produce the fine-line, thin-metal grid structures that are required to fabricate high-efficiency solar cells. During the first quarter of this contract, a comprehensive literature search was carried out in the various state-of-the-art laser-assisted techniques for metal deposition, including laser chemical vapor deposition and laser photolysis of organometallics, as well as laser-enhanced electroplating. A compact system for the experiments involving laser-assisted photolysis of gas-phase compounds was designed and constructed. The work performed in the second quarter is detailed in this report. Metal deposition experiments have been carried out utilizing laser-assisted pyrolysis of a variety of metal-bearing polymer films and metallo-organic inks spun onto silicon substrates. Laser ...
The two-phase annular regime is characterized by a high velocity gas stream flowing through the core of the tube surrounded by a thin, highly agitated liquid film flowing concurrently along the tube wall. Part of the liquid may be entrained as droplets in the gas phase. The specific goals of this study were to measure fully developed rates of interchange and entrained fraction over a wide range of flow variables in the upward configuration of the annular regime, to obtain a more fundamental understanding of liquid interchange phenomena via studies of liquid film characteristics and to develop an improved design correlation for the entrained fraction. Towards this end, air-water experiments were conducted in two vertical pipe lines, 2.54 and 4.20 cm in diameter. Air velocities ranging from 20 to 120 m/s and total liquid flow rates ranging from 10 to 100 g/s were investigated. Two models for the rate of atomization, proposed by Tatterson (1975) and Leman (1985), were ...
Ford, Bacon, Davis Utah Inc. has reevaluated the Spook site in order to revise the December 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings 48 mi northeast of Casper, in Converse County, Wyoming. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 187,000 tons of tailings at the Spook site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors.
Ford, Bacon and Davis Utah Inc. has reevaluated the Tuba City site in order to revise the March 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Tuba City, Arizona. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 0.8 million tons of tailings at the Tuba City site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors.
Chapter one is a review of the relevant literature. In chapter two the coordination chemistry of biphenyl-tailed terpyridines with octahedral metal dications is investigated. The effect of different metal ions on their aggregation modes in the solid state is also investigated. In chapter three the coordination chemistry of polyaryl-tailed terpyridines with octahedral metal dications is investigated. The effect of different aryl tails on their aggregation modes in the solid state is investigated. In chapter four the pi-pi aggregation of molecular boxes through biphenyl tails is studied. In chapter five the immobilisation of aryl tailed complexes into polyelectrolyte films has been investigated, and the arrangement of these complexes in the films has been compared with same complexes in the crystal, thus moving from three dimensional aggregation to two dimensions.
Whereas supersaturated aluminum alloys demonstrate enhanced passivity, conventional aluminum alloys spontaneously pit in air-saturated chloride solutions. We have concentrated on three areas: evaluation and characterization of Al-W alloys, which exhibit the best corrosion performance of any alloy system studied to date; characterization of the passive-film structure of Al-Mo alloys; and production and characterization of Al-W and Al-Ta powders, which will be used for compaction into bulk material. Surface analysis of the Al-W passive films formed during polarization show surprising little oxidized solute compared to other alloys. These results indicate that the barrier layer formation and electrostatic repulsion mechanisms used to explain the passivity of other alloys are not involved here. Instead the W may act to stabilize the passive film structure in a way similar to the way molybdenum acts in Al-Mo alloys. That is ...
A novel composite film, comprising of hydrophobic ionic liquid (IL), multi-walled carbon nanotubes (MWNTs) and gold nanoparticles (GNP), was fabricated and characterized. The GNP was introduced through electrochemical deposition on IL-MWNT gel film coated glassy carbon electrodes (GCE). Experiments showed that both IL and MWNTs could facilitate the GNP deposition. With GNP the composite film exhibited smaller electron transfer resistance and higher sensitivity in sensing guanine (G) and adenine (A). Under the optimized experimental conditions, the anodic peak currents were linear to the analyte concentration in the ranges of 0.008-2.0 {mu}M. The detection limits were down to nanomole level after an accumulation of 150 s on open-circuit. In addition, on the composite film coated GCE, the anodic peaks of G and A were well separated, and their response sensitivities kept almost unchanged no matter whether they coexisted or ...
A novel composite film, comprising of hydrophobic ionic liquid (IL), multi-walled carbon nanotubes (MWNTs) and gold nanoparticles (GNP), was fabricated and characterized. The GNP was introduced through electrochemical deposition on IL-MWNT gel film coated glassy carbon electrodes (GCE). Experiments showed that both IL and MWNTs could facilitate the GNP deposition. With GNP the composite film exhibited smaller electron transfer resistance and higher sensitivity in sensing guanine (G) and adenine (A). Under the optimized experimental conditions, the anodic peak currents were linear to the analyte concentration in the ranges of 0.008-2.0 ?M. The detection limits were down to nanomole level after an accumulation of 150 s on open-circuit. In addition, on the composite film coated GCE, the anodic peaks of G and A were well separated, and their response sensitivities kept almost unchanged no matter whether they coexisted or not. ...
In this work we investigate an iron oxide thin film grown with atomic layer deposition for a gas sensor application. The objective is to characterize the structural, chemical, and electrical properties of the film, and to demonstrate its gas-sensitivity. The obtained scanning electron microscopy and atomic force microscopy results indicate that the film has a granular structure and that it has grown mainly on the glass substrate leaving the platinum electrodes uncovered. X-ray diffraction results show that iron oxide is in the #alpha#-Fe_2O_3 (hematite) phase. X-ray photoelectron spectra recorded at elevated temperature imply that the surface iron is mainly in the Fe"3"+ state and that oxygen has two chemical states: one corresponding to the lattice oxygen and the other to adsorbed oxygen species. Electric conductivity has an activation energy of 0.3-0.5 eV and almost Ohmic current-voltage dependency. When exposed to O_2 and CO, a typical ...
To predict air quality properly at a given location, it is necessary to identify all emission sources that will have significant impact at that location. Furthermore, the atmospheric pollutants that are emitted by these sources must be identified and quantitatively characterized. Once the air-quality predictions have been made, it is desirable to have some historical air-quality data for comparison. An efficient means of obtaining this information is through the use of detailed emission inventories and an inventory of air-quality-monitoring stations. Therefore, as part of the Alberta Government/Industry Acid Deposition Research Program (ADRP), three comprehensive inventories have been developed, namely: a sulfur dioxide (SO/sub 2/) emission inventory, a nitrogen oxides (NOx) emission inventory, and an inventory of air-quality-monitoring stations. Volume 2, Design of the Emission Inventory, presents detailed information on the classification ...
Metal-organic chemical vapor deposition (MOCVD) made layers of strontium-bismuth-tantalate (SBT) were characterized by spectroscopic ellipsometry (SE) using the Adachi model [S. Adachi, Phys. Rev. B 35 (1987) 7454-7463]. The evaluated optical parameters were correlated with the physical and chemical behavior examined by X-ray diffraction (XRD). As a result, it was possible to fit the measured spectra with the Adachi model in a wide range covering the region of the band gap. The Adachi model provides electronic layer parameters like the transition energy E 0 and broadening ?. Our investigations established a correlation between XRD-determined average grain size and the electronic layer parameters.
Fluorinated amorphous carbon (a-C:F) films were deposited by radio frequency bias assisted microwave plasma electron cyclotron resonance chemical vapor deposition with tetrafluoromethane (CF_4) and acetylene (C_2H_2) as precursors. The deposition process was performed at two flow ratios R=0.90 and R=0.97, where R=CF_4/(CF_4+C_2H_2). The samples were annealed at 300 deg. C for 30 min. in a N_2 atmosphere. Both Fourier transform infrared and electron spectroscopy for chemical analyzer were used to characterize the a-C:F film chemical bond and fluorine concentration, respectively. A high resolution electron energy loss spectrometer was applied to detect the electronic structure. The higher CF_4 flow ratio (R=0.97) produced more sp"3 linear structure, and it made the a-C:F film smoother and softer. A lifetime of around 0.34 #mu#s and an energy gap of #approx#2.75 eV were observed in both the ...
Acid mine drainage represents one of the most important environmental problem facing the mining industry. If the tailings contain sulphur, acid mine drainage will be generated as soon as the tailings are exposed to oxygen. In this paper, the authors discussed a technique for the storage of acid mine drainage generating tailings that delays and even eliminates the occurrence. It was suggested that tailings should be piled by incorporating, at regular intervals, compacted waste rock. Thermal convection and diffusion will prevent oxygen from reaching the tailings, and limit water circulation. The modelling of transfer processes (heat, water, oxygen) in a well known tailings dump, the Doyon Mine, was performed, and the results compared to the modelling where compacted waste rock had been incorporated at regular intervals. The results indicated that by remaining ...
In the past decade, the large tailings pond (Mildred Lake Settling Basin) on the Syncrude Canada Ltd. lease near Fort McMurray, Alta., has gone methanogenic. Currently, about 60%-80% of the flux of gas across the surface of the tailings pond is methane. As well as adding to greenhouse gas emissions, the production of methane in the fine tailings zone of this and other settling basins may affect the performance of these settling basins and impact reclamation options. Enumeration studies found methanogens (10(5)-10(6) MPN/g) within the fine tailings zone of various oil sands waste settling basins. SRB were also present (10(4)-10(5) MPN/g) with elevated numbers when sulfate was available. The methanogenic population was robust, and sample storage up to 9 months at 4 degrees C did not cause the MPN values to change. Nor was the ability of the consortium to produce methane delayed or less efficient after ...
Menopause is characterized by the progressive reduction of estrogens resulting to cessation of menses. It is associated with an increase of cardiovascular risk factors such as hyperglycemia, hypertension, dyslipidemia and of abdominal and/or selective visceral fat mass deposition. Obesity, a modern day epidemic, is promoted by an obesogenic environment that interacts with the genetic background. The result is a positive energy balance materialized by the accumulation of the adipose tissue. This process is marked by great individual variation. Obesity is also associated with the presence of cardiovascular risk factors. In this review, the main pathophysiologic processes for the increase of obesity in menopause and the possible effects of pre-menopausal obesity regarding the cessation of ova...
The Joint European Torus (JET) fusion machine is the only device capable of operation with tritium (as fuel) and Be (as plasma facing component), what makes it best suited to study ITER relevant issues. A large variety of activities are performed within the JET Fusion Technology Task Force. In this paper, some topics such as erosion/deposition and material transport, flakes characterization and detritiation techniques are highlighted. Recent results obtained using a pumping cryo-panel and on plasma facing component characterisation are given. Finally, issues that will be addressed in the forthcoming JET work-programme are presented, such as a beryllium main wall for JET and in-situ laser detritiation. (authors)
The paper is concerned with the simulation of practical testing situations which are too difficult and/or expensive to replicate in a laboratory environment. Numerical experiments are described which simulate the differential eddy current probe response to the build-up and chemical flushing of magnetite in the crevice gap of a PWR steam generator unit. The simulation results agree well with the only experimental data available to the authors and lead to the conclusion that conventional differential eddy current probes should be capable of characterizing crevice gap conditions with respect to the presence of magnetite. (author).
Absolute fission rate measurements using modified National Bureau of Standards fission chambers were performed in the Fast Flux Test Facility at two core locations for isotopic deposits of {sup 232}Th, {sup 233}U, {sup 235}U, {sup 238}U, {sup 237}Np, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu. Monitor chamber results at a third location were analyzed to support other experiments involving passive dosimeter fission rate determinations.
Absolute fission rate measurements using modified National Bureau of Standards fission chambers were performed in the Fast Flux Test Facility at two core locations for isotopic deposits of {sup 232}Th, {sup 233}U, {sup 235}U, {sup 238}U, {sup 237}Np, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu. Monitor chamber results at a third location were analyzed to support other experiments involving passive dosimeter fission rate determinations.
Results are reported from initial characterization tests on the environmental effects of the natural draft cooling tower of the Chalk Point Unit 3 oil-fired power plant located on the shore of Chesapeake Bay. Data are included on updraft air velocity, plume drift, and sea salt deposition in relation to meteorological conditions.
The Lower Cretaceous Falher Member (Spirit River Formation) in the Deep Basin of Alberta is composed of 5 units (A-E) comprising the reservoir of the giant Elmworth gas field. Using high resolution sequence stratigraphy, 333 well logs and 65 cores were integrated to understand the evolution of Falher C and D in the study area. Five major faces associations were defined in each unit. The basal surface of Falher D overlies nonmarine deposits (Falher E) and is defined by a marine flooding surface (transgressive surface of erosion) partially modified by a subsequent regressive surface of erosion. Southward, all the facies become more continental and the marine flooding surface passes into a lagoon-on-nonmarine contact. Falher D contains a series of shingled marine sandstone lenses separated by erosional surfaces interpreted as seaward-dipping ravinement surfaces indicating different phases of marine transgression-regression. The Falher C basal surface is a marine ...
The Westinghouse Electric Corporation has undertaken to investigate, develop, and characterize laser-assisted processing techniques utilized to produce the fine line, thin metal grid structures that are required to fabricate high-efficiency solar cells. Two basic techniques for metal deposition will be investigated, as follows: (1) photochemical decomposition of liquid or gas phase organometallic compounds utilizing either a focused, CW ultraviolet laser (System 1) or a mask and ultraviolet flood illumination, such as that provided by a repetitively pulsed, defocused excimer laser (System 2), for pattern definition, and (2) thermal deposition of metals from organometallic solutions or vapors utilizing a focused, CW laser beam as a local heat source to draw the metallization pattern. The purpose of this contract is to investigate the various existing laser-assisted film deposition techniques in order to ...
Based on their interesting properties, metal nanoparticles show the potential as an analytical tool in electronic (Burmeister et al. 2004), optical (Yguerabide and Yguerabide 1998), and catalytic applications (Liu 2006). Their characteristics depend on the composition, shape, and size of the single particles. These various properties are utilized in many different approaches such as optics, magnetics (Lang et al. 2007), and laser technology (Csaki et al. 2007). We investigated an alternative method for the synthesis of nanoparticles. In this case, an enzyme, horseradish peroxidase, induces a silver deposition and replaces a metal nanoparticle as the reaction seed. Depending on the reaction time, we could obtain particles in a range of few nanometers up to more than 250 nm. For a better understanding of the enzymatic silver deposition process, the silver particles produced by this process were analyzed by SEM, TEM, and atomic force microscopy ...
For obtaining radiation less damagable laser mirrors, a preliminary optimization of film fabrication suitable for the analysis of laser damage mechanism has been done as the first step. Here, the optimization requires not only the stable fabrication process but also the ideal film structure i.e., the amorphous and smooth film structure simultaneously, eliminating latently unwanted secondary effects such as light scattering during laser damage test. For this purpose, we adopted the ion assisted deposition (IAD) method and modified the deposition conditions for titanium and tantalum oxide films, both of which compose typical high index layers, and where SiO_2 layers are also chosen as low index layers because of their amorphous and smooth nature, in alternative multilayer laser mirrors. Surface and cross sectional film structures and film crystallinity are compared and characterized, using a high resolution SEM and a x-ray ...
Wear-resistant TiN coatings deposited on tool steels are used frequently in industry. There is a trend towards further optimizing these coatings, e.g. by plasma nitriding the tool surface prior to TiN deposition. In this work the influence of the nitriding conditions on the surface properties of AISI 304 and ASP 23 tool steels was investigated. The plasma nitriding was carried out in a triode ion plating configuration normally used to deposit TiN coatings. At the surface of AISI 304 stainless steel, only a thin compound layer (Fe{sub 4}N, Fe{sub 3}N) was found, probably as a consequence of the rather slow nitrogen diffusion in the austenite matrix. For ASP 23 high speed steel, the different nitriding behaviour of the martensitic matrix causes the formation of a diffusion layer which results in an increase in hardness at the surface. On an analogous set of specimens the TiN deposition was started ...
Hydrocarbon recovery efficiency is controlled by reservoir heterogeneities resulting from geometric arrangements of strata, or {open_quotes}stratal architecture{close_quotes}. Traditional reservoir characterization relates depositional systems to stratal architecture. High-resolution sequence stratigraphy of outcrop analogs provides a chronostratigraphic framework for evaluating accommodation conditions of depositional systems. Key stratigraphic surfaces and/or correlative strata define a hierarchy of chronostratigraphic units of different periodicities. The Upper Cretaceous Ferron Sandstone, an analog to high accommodation and sediment supply fluvial-deltaic reservoirs, comprises an intermediate-term stratigraphic sequence consisting of seven short-term stratigraphic cycles. Each short-term stratigraphic cycle contains fluvial- to storm-dominated shallow-marine deposits laterally replaced by ...
The pure xenon dc positive column discharge has been characterized for various xenon pressures, currents, and discharge tube radii. The absolute output at the 147 nm resonance transition has been measured using two independent techniques to yield the radiant emittance at 147 nm (power per unit surface area). The efficiency of 147 nm production is obtained by combining the measured radiant emittance with the measured electrical power per unit length deposited in the gas. The radiant emittance and the efficiency are the two principle figures of merit for characterizing the discharge as a source of VUV radiation. It is observed that the trends in efficiency and radiant emittance change substantially when the discharge transitions from two-step electron impact excitation/ionization at higher pressures to single-step electron impact ionization at lower pressures. Modeling of the xenon positive column discharge yields radiant ...
High pressure xenon ionization chamber detectors are possible alternatives to traditional thallium doped sodium iodide (NaI(Tl)) and hyperpure germanium as gamma spectrometers in certain applications. Xenon detectors incorporating a Frisch grid exhibit energy resolutions comparable to cadmium/zinc/telluride (CZT) (e.g. 2% (at) 662keV) but with far greater sensitive volumes. The Frisch grid reduces the position dependence of the anode pulse risetimes, but it also increases the detector vibration sensitivity, anode capacitance, voltage requirements and mechanical complexity. We have been investigating the possibility of eliminating the grid electrode in high-pressure xenon detectors and preserving the high energy resolution using electronic risetime compensation methods. A two-electrode cylindrical high pressure xenon gamma detector coupled to time-to-amplitude conversion electronics was used to characterize the pulse rise time of deposited gamma ...
The sensitivity analysis summarized in this paper was made to determine the parameters of greatest influence in the prediction of radon barrier cover thickness for the stabilization of uranium mill tailings piles. Such information provides the basis for setting priorities and levels of effort for data collection, and improves knowledge of the sources of uncertainty in the calculation of cover thickness. In the context of this paper, the influence of a parameter on cover thickness incorporates two effects: (1) the sensitivity of the mathematical formulation to changes in a parameter's value, and (2) the range of values that a parameter may take on under site-specific conditions. Of the several parameters that are used in the calculations, the most influential are cover moisture content, cover radon diffusion coefficient, tailings radium concentration and tailings radon emanating fraction, in order of decreasing relative ...
The production of de-inked tailings in Quebec has significantly increased during the last decade. From less than 100,000 wet tons in 1990, the production of de-inked tailings reached 500,000 wet tons in 1995, and 510,000 wet tons in 1999. The geotechnical, hydraulic, and physico-chemical properties of de-inked tailings are favorable for its use as soil cover for the prevention of acid mine drainage at mining sites. In this presentation, the authors discussed the three-year monitoring of the behaviour of a membrane covering an old mining site with the potential to produce acid mine drainage. The site is located at the Clinton Mine, near Woburn, Quebec. The mine shaft was filled with the tailings and waste rock scattered around the site and covered with a protective membrane which included de-inked tailings. The profile of the membrane was discussed, as well as construction details. ...
This document describes the results of accelerated aging tests to determine the long-term effectiveness of selected impoundment liner materials in a uranium mill tailings environment. The study was sponsored by the US Department of Energy under the Uranium Mill Tailings Remedial Action Project. The study was designed to evaluate the need for, and the performance of, several candidate liners for isolating mill tailings leachate in conformance with proposed Environmental Protection Agency and Nuclear Regulatory Commission requirements. The liners were subjected to conditions known to accelerate the degradation mechanisms of the various liners. Also, a test environment was maintained that modeled the expected conditions at a mill tailings impoundment, including ground subsidence and the weight loading of tailings on the liners. A comparison of installation costs was also performed for ...
Laser-assisted processing techniques for producing high-quality solar cell metallization patterns have been investigated, developed, and characterized. During the early stages, preliminary investigations were carried out on a variety of promising laser-assisted metallization schemes, and the best of these was selected for further development. A comprehensive literature search initially yielded information on state-of-the-art laser-assisted techniques for metal deposition such as laser chemical vapor deposition and laser photolysis of organometallics, as well as laser-enhanced electroplating. Initial experiments on laser-enhanced electroplating yielded very promising results with linewidths as narrow as 25 ..mu..m and local plating speeds as high as 12 ..mu..m/s being achieved. Metal deposition experiments were carried out utilizing laser-assisted pyrolysis of a variety of metal-bearing polymer films and ...
Deer Elk Bighorn Sheep American Pronghorn Moose Deer Mouse Carnivores Bobcat American Badger River Otter Red Fox Long-Tailed Weasel Coyote Grizzly Bear Mountain Lion Amphibians...
Soil placed over any sealant/barrier system can provide a protective mantle if the soil is not lost by erosion. Vegetation is an attractive choice for controlling erosion because it can provide an economic self-renewing cover that serves to reduce erosion by both wind and water. Vegetation alone, however, may not adequately stabilize the surface in extremely arid areas. In those areas, a properly designed surface treatment of rock cover, perhaps in conjunction with vegetation, may be necessary to stabilize the tailings surfaces. The objective of this program is to establish guidelines for surface stabilization that are compatible with sealant/barrier systems and that are suited to soils and climates at inactive uranium mill tailings sites. These guidelines will provide the means to estimate potential vegetation cover, potential erosion, effects of surface treatments on sealant/barrier systems, and costs of vegetation and rock covers. Methods ...
Studies of asphalt emulsion sealants conducted by the Pacific Northwest Laboratory have demonstrated that the sealants are effective in containing radon and other potentially hazardous material within uranium tailings. The laboratory and field studies have further demonstrated that radon exhalation from uranium tailings piles can be reduced by greater than 99% to near background levels. Field tests at the tailings pile in Grand Junction, Colorado, confirmed that an 8-cm admix seal containing 22 wt% asphalt could be effectively applied with a cold-mix paver. Other techniques were successfully tested, including a soil stabilizer and a hot, rubberized asphalt seal that was applied with a distributor truck. After the seals were applied and compacted, overburden was applied over the seal to protect the seal from ultraviolet degradation.
Studies of asphalt emulsion sealants have demonstrated that the sealants are effective in containing radon and other potentially hazardous material within uranium tailings. The laboratory and field studies have further demonstrated that radon exhalation from uranium tailings piles can be reduced by greater than 99% to less than background levels. Field tests at the tailings pile in Grand Junction, Colorado confirmed that an 8-cm admix seal containing 22 wt % asphalt could be effectively applied with a cold-mix paver. Other techniques were successfully tested, including a soil stabilizer and a hot, rubberized asphalt seal that was applied with a distributor truck. After the seals were applied and conpacted, overburden was applied over the seal to protect the seal from ultraviolet degradation. 14 figures.
In several respects the dorsal thalamus of Trichosurus presents a level of organizational complexity considerably in advance of that seen in Didelphis. In particular, such features as the lamination...Full Text Available
By magnetron sputtering model steel films with specific properties can be prepared for purposive surveys. By changing the deposition parameters certain properties of these films can be influenced. For this thesis steel films with 18% Cr and 8% Ni have been prepared in order to study specific parameters on the corrosion resistance of bulk stainless steel. Chemical composition, microstructure, and surface morphology of these films have been characterized. In comparison to bulk steel sheets with the same chemical composition they have a smaller grain size and a ferritic structure. In contrast to bulk steel sheets they don`t contain any nonmetallic inclusions like Mn-sulfides. The influence of these structural differences on the corrosion resistance has been studied. For this purpose the electrochemical properties of the sputter-deposited steels have been compared with the properties of steel sheets with a similar chemical ...
Significant ion irradiation during film growth is required for the formation of cubic boron nitride (cBN) films. Meanwhile, a huge level of intrinsic stress possibly induced by the ion bombardment has been frequently reported to result in cracking and/or lack of adhesion of deposited cBN films. The present work has been performed to investigate the interfacial and/or the buffer layer structures with better matching to the cBN film by relaxation of the film stress using ion-beam-assisted deposition (IBAD). Boron nitride films have been synthesized on Si(100) wafer and tungsten carbide (WC) substrates by depositing boron vapor under simultaneous bombardment with nitrogen ions and nitrogen-argon mixture ions in the energy range of 0.5-10 keV. Cubic BN films with enhanced tribological properties have been explored by inserting a BN layer with various B/N compositions as a controlled buffer at the interface. Significant ...
Thirty-three measured sections of the Dinwoody Formation, including five from the literature, provide information on thickness, lithology, paleontology, and stratigraphic relations within the Wind River basin and immediately adjacent areas of Wyoming. Most of these sections are in Fremont County, and some lie within the Wind River Indian Reservation. The Dinwoody becomes progressively thinner eastward, from a maximum thickness of 54.6 m in the northwestern Wind River Mountains to zero near the Natrona County line. The formation is characterized by yellowish-weathering, gray siltstone and silty shale. Variable amounts of limestone, sandstone, gypsum, and claystone are also present. Marine bivalves, gastropods, brachiopods (Lingula), and conodonts are common in the western part of the study area, but are absent to the northeast in gypsiferous strata, and near the eastern limit of Dinwoody deposition. The Dinwoody in the Wind River Basin area was ...
There are five tasks within this project on thermally stable coal-based jet fuels. Progress on each of the tasks is described. Task 1, Investigation of the quantitative degradation chemistry of fuels, has 5 subtasks which are described: Literature review on thermal stability of jet fuels; Pyrolytic and catalytic reactions of potential endothermic fuels: cis- and trans-decalin; Use of site specific {sup 13}C-labeling to examine the thermal stressing of 1-phenylhexane: A case study for the determination of reaction kinetics in complex fuel mixtures versus model compound studies; Estimation of critical temperatures of jet fuels; and Surface effects on deposit formation in a flow reactor system. Under Task 2, Investigation of incipient deposition, the subtask reported is Uncertainty analysis on growth and deposition of particles during heating of coal-derived aviation gas turbine fuels; under Task 3, ...
In this work we present the electrical characterization of non self-aligned p-channel thin film transistors fabricated by using laser doping technique for source/drain contact formation and gate oxide deposited at room temperature by Electron Cyclotron Resonance Plasma Enhanced Chemical Vapour Deposition. These techniques are suitable for a very low temperature process for TFT fabrication. The output characteristics show a current increase at high drain voltage ('kink' effect) rather moderate, if compared to self aligned polysilicon TFTs, probably due to the gradual doping profile induced by laser doping process. After bias stress at low gate voltage and high drain voltage condition a strong reduction of kink current has been observed in the output characteristics at high drain voltage, whereas minor changes has been observed in the transfer characteristics. This behaviour is similar to what observed in ...
In this work we present the electrical characterization of non self-aligned p-channel thin film transistors fabricated by using laser doping technique for source/drain contact formation and gate oxide deposited at room temperature by Electron Cyclotron Resonance Plasma Enhanced Chemical Vapour Deposition. These techniques are suitable for a very low temperature process for TFT fabrication. The output characteristics show a current increase at high drain voltage ('kink' effect) rather moderate, if compared to self aligned polysilicon TFTs, probably due to the gradual doping profile induced by laser doping process. After bias stress at low gate voltage and high drain voltage condition a strong reduction of kink current has been observed in the output characteristics at high drain voltage, whereas minor changes has been observed in the transfer characteristics. This behaviour is similar to what observed in n-channel Gate ...
Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} thin films were successfully prepared by the solution deposition using lithium acetate, aluminum nitrate, ammonium dihydrogen phosphate and titanium butoxide as starting materials. The structure, surface morphology, electrochemical window, and ionic conductivity of the films were studied by X-ray diffraction, scanning electron microscopy, cyclic voltammetry and AC impedance. The results showed that Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} thin films annealed between 750 deg. C and 900 deg. C prepared by this method were well crystallized, homogenous and crack-free. The electrochemical window was beyond 2.4 V and the ionic conductivity was approximately 1.57x10{sup -5} S/cm at room temperature for the film annealed at 800 deg. C for 30 min.
Li_1_._3Al_0_._3Ti_1_._7(PO_4)_3 thin films were successfully prepared by the solution deposition using lithium acetate, aluminum nitrate, ammonium dihydrogen phosphate and titanium butoxide as starting materials. The structure, surface morphology, electrochemical window, and ionic conductivity of the films were studied by X-ray diffraction, scanning electron microscopy, cyclic voltammetry and AC impedance. The results showed that Li_1_._3Al_0_._3Ti_1_._7(PO_4)_3 thin films annealed between 750 deg. C and 900 deg. C prepared by this method were well crystallized, homogenous and crack-free. The electrochemical window was beyond 2.4 V and the ionic conductivity was approximately 1.57x10"-"5 S/cm at room temperature for the film annealed at 800 deg. C for 30 min.
Iron oxide thin films were prepared by spray pyrolysis technique onto glass substrates from iron chloride solution. They were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and (UV-vis) spectroscopy. The films deposited at T _s #<=# 450 deg. C were amorphous; while those produced at T _s_u_b = 500 deg. C were polycrystalline #alpha#-Fe_2O_3 with a preferential orientation along the (1 0 4) direction. By observing scanning electron microscopy (SEM), it was seen that iron oxide films were relatively homogeneous uniform and had a good adherence to the glass substrates. The grain size was found (by RX) between 19 and 25 nm. The composition of these films was examined by X-ray photoelectron spectroscopy and electron probe microanalysis (EPMA). These films exhibited also a transmittance value about 80% in the visible and infrared range. The cyclic voltammetry study showed ...
Attempt to form the Schottky barrier on mercury indium telluride (MIT) surface by deposition transparent conducting electrode (TCE) and avoid the negative results by non-rectifier contacts nature, we have investigated the oxidation of clean MIT surfaces to form an insulating layer to overcome this disadvantage by metal-insulator-semiconductor (MIS) photodetectors designing. Oxide film is grown on the MIT surface by plasma enhance chemical vapor deposition (PECVD). Previously cleaned MIT wafers were dipped and boiled in solution, which consists of mixture of bromine and an organic solvent in ratio of 1:50. By the way of using these films as intermediate slightly conducting insulator, a fast-response MIT based surface-barrier photodetectors have been developed. Pt films were used as TCE frontal electrode by vacuum magnetron sputtering (VMS). The current-voltage characteristic is described quantitatively based on the energy diagram and the found ...
Herein, we report engineering of nanostructured p-CuIn3Se5/n-CdS heterojunction thin film on a glass substrate, which is prepared at room temperature using simple wet chemical approach involving ion exchange reactions between CdS and Cu^+, In^3^+ and Se^2^- ions in alkaline medium. The uniform deposition of heterojunction thin films is achieved by optimizing the pH, temperature and molarity of the reactant bath. The as-deposited thin-films were annealed at 200^oC in air for 1h and further characterized for structural, optical and electrical properties using UV-Vis spectrophotometer, X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), Hall effect for type of conductivity, and I-V measurement to investigate the char...
There is an increasing number of applications for hard coatings in engineering where the properties of the single-layer coating are not sufficient. One way to solve this problem is to use a multilayer coating that combines the properties of several coating materials. In this study, TiN-CrAlN and CrN-CrAlN multilayer coatings were deposited on 100Cr6 and S6-5-2 (DIN) steel substrates, by means of unbalanced magnetron sputtering. For comparison, TiN, CrN and CrAlN single-layer coatings were also prepared. For all depositions the coating temperature was below 473 K. Indentation testing, hardness measurements and scratch tests were performed to characterize the mechanical properties. The correlation between the wear behavior in rolling contact and the mechanical properties of the multilayer coatings is reported. A ball crater preparation technique through scratch tests and wear tracks was used to observe the deformation and ...
High-resolution sequence stratigraphy concepts are applied to Erema, a Miocene onshore field of the Niger delta. The field's production is decreasing and an up-to-date geological model is essential to monitor the production. We aim to show an approach, using subsurface data and sequence stratigraphic concepts, which results in a time-line (Maximum Flooding Surfaces) correlation scheme. This scheme is based upon a facies model and is destined to guide the study of the characterization of reservoir heterogeneities. Using the cored well as a reference point, the facies model consists of shoreface dunes (planar tabular cross-stratified sandstones) changing landward into fluvial distributary deposits (through cross-stratified sandstones) via a tide-influenced coastal plain facies. The stacking pattern of genetic units shows a seaward stepping phase at the reservoir scale (sixty metres thick) with an abrupt deepening at the top of the ...
The deactivation rate of a resid hydrotreating catalyst is determined by a complex set of factors involving both chemical and physical changes in the catalyst structure. The various chemical changes that are associated with resid conversion involve thermal and catalytic steps of relatively large molecular weight species with the overall rates significantly affected by mass transfer limitations. The deposition of coke and the variation in the effective promoter level by the accumulation of metals deposited from the resid are the principal factors governing deactivation. The relative importance of mass transfer restrictions on activity and catalyst deactivation can be observed in studies where the average pore diameter of the catalyst has been varied. Several models have been proposed to characterize the deactivation of resid hydroprocessing catalysts. In this paper, the authors discuss some accelerated aging tests with a ...
Metastable yttrium-oxide films are synthesized using reactive sputter deposition. The yttrium concentration of the as-deposited film is found to vary as a function of the sputter deposition rate. In addition to the synthesis of the cubic equilibrium phase...
Heat transfer processes use fluids which are generally not pure and can react with transfer surfaces. These surfaces are subject to deposits which can be sediments harmful to heat transfer and to integrity of materials. For nuclear plant steam generators, sludge build-up accelerates secondary side corrosion by concentrating chemical species. A major safety problem involved with such a corrosion is the growing of circumferential cracks which are very difficult to detect and size with eddy current probes. With a view to understand and control this problem, it is necessary to develop a mathematical model for the prediction of sludge behavior in PWR steam generators. Based on fundamental principles, this work intends to use different models available in literature for the prediction of the phenomenon leading to the accumulation of sludge particles at the bottom (the tubesheet) of a PWR. For that, a three-dimensional simulation of magnetite particulate fouling with the ...
In this paper, multilayer oxide nanorods were deposited in the nanopores of anodic aluminum oxide (AAO) via solution infiltration followed by heat treatment. The nanorods have a core-shell structure. First, the shell (nanotube) with the thickness of about 40nm was made of TiO"2 through the hydrolysis of (NH"4)"2TiF"6. Second, silver nanoparticles with the diameter of about 3nm were added into the TiO"2 layer through thermal decomposition of AgNO"3 at elevated temperatures. Then, cylindrical cores (nanorods) of CoO and ZnO with 200nm diameter were prepared, respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the structure and composition of the nanorods. UV-vis light absorption measurements in the wavelength range from 350 to...
Size-controllable Ag nanoparticle ultrathin films, which were fabricated by vacuum deposition method from high purity Ag wire onto cleaned indium tin oxide conducting glass, have different color fabricated by variation of preparation conditions. The UV/Vis spectra showed that optical absorption peak of these Ag nanoparticle films can be tuned in a range from 457nm to >650nm. Scanning electron microscopy images showed that with increasing film thickness Ag particle size was larger. Ag/WO3 composite films were prepared by cathodic electrodeposition of WO3 onto the surface of Ag nanoparticle films. Spectroelectrochemistry and electrochromic properties of the resulting composite films were characterized. It was found that the electrochemical and electrochromatic properties of the composite fil...
The Rotary Mode Core Sample System (RMCSS) is used to obtain stratified samples of the waste deposits in single-shell and double-shell waste tanks at the Hanford Site. The samples are used to characterize the waste in support of ongoing and future waste remediation efforts. Four sampling trucks have been developed to obtain these samples. Truck I was the first in operation and is currently being used to obtain samples where the push mode is appropriate (i.e., no rotation of drill). Truck 2 is similar to truck 1, except for added safety features, and is in operation to obtain samples using either a push mode or rotary drill mode. Trucks 3 and 4 are now being fabricated to be essentially identical to truck 2.
A Y-Mg-Si-Al-O-N glass was submitted to swift heavy-ion bombardment at GANIL (Caen, France) and the influence of irradiation on the mechanical properties was studied. The mechanical properties of the glass were characterized both before and after irradiation. Changes in hardness, elastic modulus and fracture toughness of the near-surface irradiated layer were determined using indentation techniques. SRIM calculations allowed to estimate the ions penetration range and the energy deposition relative to electronic and nuclear interactions, which can be correlated to the experimental damaged depth. Meyer's hardness and Young's modulus decrease by about 30 %, while fracture toughness is increased by more than 40 %. (authors)
We described the use of silica nanoparticles as building blocks for the immobilization of electrogenerated chemiluminescence (ECL) reagent Ru(bpy){sub 3}{sup 2+} and the fabrication of layer-by-layer assembly film by alternating the deposition of the Ru(bpy){sub 3}{sup 2+}-doped silica nanoparticles and Au nanoparticles. UV-vis absorption spectroscopy, scanning electron microscopy (SEM), cyclic voltammetry and ECL were used to characterize the uniform growth of the multilayer film. Since Ru(bpy){sub 3}{sup 2+} could still maintain its ECL property when doped into the silica nanoparticles, the as-prepared multilayer film could be used as an effective ECL sensor, and the sensor showed high sensitivity and good stability.
We described the use of silica nanoparticles as building blocks for the immobilization of electrogenerated chemiluminescence (ECL) reagent Ru(bpy)_3"2"+ and the fabrication of layer-by-layer assembly film by alternating the deposition of the Ru(bpy)_3"2"+-doped silica nanoparticles and Au nanoparticles. UV-vis absorption spectroscopy, scanning electron microscopy (SEM), cyclic voltammetry and ECL were used to characterize the uniform growth of the multilayer film. Since Ru(bpy)_3"2"+ could still maintain its ECL property when doped into the silica nanoparticles, the as-prepared multilayer film could be used as an effective ECL sensor, and the sensor showed high sensitivity and good stability.
We described the use of silica nanoparticles as building blocks for the immobilization of electrogenerated chemiluminescence (ECL) reagent Ru(bpy)32+ and the fabrication of layer-by-layer assembly film by alternating the deposition of the Ru(bpy)32+-doped silica nanoparticles and Au nanoparticles. UV-vis absorption spectroscopy, scanning electron microscopy (SEM), cyclic voltammetry and ECL were used to characterize the uniform growth of the multilayer film. Since Ru(bpy)32+ could still maintain its ECL property when doped into the silica nanoparticles, the as-prepared multilayer film could be used as an effective ECL sensor, and the sensor showed high sensitivity and good stability.
The site characterization of Yucca Mountain, NV as a potential high level nuclear waste repository includes study of the surficial deposits as a record of the paleoenvironmental history of the Yucca Mountain region. An important aspect of this history is an understanding of the evolution of paleogeography leading to establishment of the present drainage pattern. Establishment of drainage basin evolution is needed before geomorphic response to paleoclimate and tectonics can be assessed, because a major change in drainage basin geometry can predominantly affect the sedimentary record. Because alluvial aquifers are significant to regional hydrology, a major change in surface drainage resulting in buried alluvium could have hydrogeologic significance. In this paper, we report on geologic evidence for a major modification in surface drainage pattern in the Yucca Mountain region, resulting in the probable establishment of the Fortymile Wash drainage ...
Since high resolution sequence stratigraphy was introduced into China by DENG Hong-wen in 1995, it has been experienced two development stages in China which are the beginning stage of theory research and development of theory research and application, and the stage of theoretical maturity and widely application that is going into. It is proved by practices that high resolution sequence stratigraphy plays more and more important roles in the exploration and development of oil and gas in Chinese continental oil-bearing basin and the research field spreads to the exploration of coal mine, uranium mine and other strata deposits. However, the theory of high resolution sequence stratigraphy still has some shortages, it should be improved in many aspects. The authors point out that high resolution sequence stratigraphy should be characterized quantitatively and modelized by computer techniques. (authors)
A new stem cell-scaffold construct based on poly-l-lactide (PLLA) nanofibers grafted with collagen (PLLA-COL) and cord blood-derived unrestricted somatic stem cells (USSC) were proposed to hold promising characteristics for bone tissue engineering. Fabricated nanofibers were characterized using SEM, ATR-FTIR, tensile and contact angle measurements. The capacity of PLLA, plasma-treated PLLA (PLLA-pl) and PLLA-COL scaffolds to support proliferation and osteogenic differentiation of USSC was evaluated using MTT assay and common osteogenic markers such as alkaline phosphatase (ALP) activity, calcium mineral deposition and bone-related genes. All three scaffolds showed nanofibrous and porous structure with suitable physical characteristics. Higher proliferation and viability of USSC was observe...
We have investigated the diffusion of Sb in Si in the presence of defects injected by high-energy implantation of Si ions at room temperature. MeV ion implantation increases the concentrations of vacancies, which induce transient-enhanced diffusion of Sb deposited in Si. We observed a significant enhancement of Sb diffusion. Secondary ions mass spectroscopy has been performed on the implanted samples before and after annealing. Rutherford-backscattering spectrometry has been used to characterize the high-energy implantation damage. By fitting diffusion profiles to a linear diffusive model, information about atomic scale diffusion of Sb, i.e. the generation rate of mobile state Sb and its mean migration length were extracted.
We have investigated the diffusion of Sb in Si in the presence of defects injected by high-energy implantation of Si ions at room temperature. MeV ion implantation increases the concentrations of vacancies, which induce transient-enhanced diffusion of Sb deposited in Si. We observed a significant enhancement of Sb diffusion. Secondary ions mass spectroscopy has been performed on the implanted samples before and after annealing. Rutherford-backscattering spectrometry has been used to characterize the high-energy implantation damage. By fitting diffusion profiles to a linear diffusive model, information about atomic scale diffusion of Sb, i.e. the generation rate of mobile state Sb and its mean migration length were extracted.
A study of the stability of conducting fabrics of polyester (PES) coated with polypyrrole/PW12O40^3^- (organic/inorganic hybrid material) in different pH solutions (1, 7, 13) has been done. Washing tests were also done in views of its possible application in electronic textiles such as antistatic clothing. X-ray photoelectron spectroscopy (XPS) studies have been done to quantify the amount of counter ion that remains in the polymer matrix and determine the doping ratio (N^+/N) after the different tests. Scanning electron microscopy (SEM) was also used to observe morphological differences after the different tests. Surface resistivity changes were measured by means of electrochemical impedance spectroscopy (EIS). Scanning electrochemical microscopy (SECM) was employed to measure changes in ...
The effects of focused-ion-beam-induced damage on electrical properties of n-type Si are investigated by Schottky contacts. Crystalline Si is exposed to 10-30 keV focused ion beam (FIB), followed by Pt deposition under vacuum of 4x10"-"4 Pa. From current-voltage-temperature measurements, barrier heights of the Schottky contacts are found to increase almost linearly as the FIB energy increases, with the maximum increment of 0.29 eV. The increase is suggested to be related to the arising of acceptorlike defects and an amorphous layer due to FIB damages. A theoretical model is set up to quantitatively describe the barrier height changes.
Soil placed over any sealant/barrier system can provide a protective mantle if the soil is not lost by erosion. Vegetation is an attractive choice for controlling erosion because it can provide an economical self-renewing cover that serves to reduce erosion by both wind and water. The objective of this research and development effort is to select and test vegetation strategies, including the choice of species and methods for revegetation that are compatible with sealant/barrier systems and are suited to soils and climates at inactive uranium mill tailings sites.
To determine if white-tailed deer may serve as a reservoir host for Borrelia lonestari, we used a nested PCR for the Borrelia flagellin gene to evaluate blood samples...Full Text Available
The surface of Si and thin layers of Pd{sub 2}Si on Si have been studied by low-energy He{sup +} ion scattering. The occurrence of the observed low-energy tails is attributed to reionization at the surface of He neutrals scattered from subsurface layers. It is shown that the tails provide in-depth information. (orig.).
The purpose of this new industrial chair is to ensure the continuation and development of new research activities in the field of environment protection as it relates to the good management of mine tailings. The mining industry plays a vital role in the economy of a number of regions in both Quebec and Canada and also causes environmental problems due to the generation of liquid, solid, and gaseous wastes. Mine tailings can cause acid mine drainage. This acid mine drainage (AMD) can have detrimental effects on the ecosystems adjoining tailings or waste rock piles. We must remain aware that some of the remedial measures instituted to contain AMD might cause problems due to their possible instability. Despite the fact that instability is a rare occurrence, it can have disastrous effects on the environment as demonstrated in Spain, Guyana, and the Philippines during the last few years. The creation of this chair in environment ...
Acid Rock Drainage (ARD) is the product formed by the atmospheric oxidation of the relatively common pyrite and pyrrhotite. Waste rock dumps and tailings containing sulfide mineral have been reported at toxic materials producing ARD. Mining in sulphide bearing rock is one of activity which may lead to generation and release of ARD. ARD has had some major detrimental affects on mining areas. The purpose of this study was carried out to develop disposal method for preventing contamination of water and soil environment by waste rocks dump and tailings, which could discharge the acid drainage with high level of metals. Scope of this study was as following: environmental impacts by mine wastes, geochemical characteristics such as metal speciation, acid potential and paste pH of mine wastes, interpretation of occurrence of ARD underneath tailings impoundment, analysis of slope stability of tailings dam etc. ...
Environmental research related to uranium tailings is being carried out within the Mining Research Laboratories and Mineral Sciences Laboratories of CANMET, EMR. Field-related research on uranium tailings has been conducted at Elliot Lake for over five years. Much of the work has been focused on a program to rehabilitate pyritic tailings. This has resulted in developing a practicable technology for growing vegetation on such wastes. Limitations have been small size of the test-plots and the relatively short period during which experiments have been carried out. A research program aimed at identifying and reducing acidic and radioactive effluents is also underway at Elliot Lake. These liquid effluents have been identified as the most serious threat to the environment. Research at the Mineral Sciences Laboratories and its predecessor divisions relating to the processing of uranium and thorium ores is outlined. A process has ...
Arsenic in soils from the Asarco lead smelter in East Helena, Montana was characterized by X-ray absorption spectroscopy (XAS). Arsenic oxidation state and geochemical speciation were analyzed as a function of depth (two sampling sites) and surface distribution. These results were compared with intensive desorption/dissolution experiments performed in a pH stat reactor for samples from the site with the highest degree of As heterogeneity. The objectives of the study were to investigate the solid-phase geochemical As speciation, assess the speciation of As in solutions equilibrated with the solids under controlled pH (pH=4 or 6) and Eh (using hydrogen or air) environments, observe the effects of phosphate on the release of As into solution, and examine the effects of phosphate on metal mobility in the systems. Arsenic was predominantly found in the As(V) valence state, though there was evidence that As(III) and As(0) were present also. The dominant geochemical phase ...
Red mud is a waste and tail material from primary aluminum production, and is named for its color, coming from its iron oxide content. The quantity of red mud is almost equal to the primary aluminum production and leads to a considerable environmental issue. Red mud of the ETI Seydisehir Aluminum Plant is considered as detrimental waste for storage due to its content of various metal oxides, elements and caustics. This detrimental effect is classified into two groups: first, environmental health and second, the cost of storage. In order to minimize the negative effect of red mud, there have been or are presently many investigations carried out on usage of red mud in building materials. However, no effective way of utilizing red mud has yet been found. In this study domestic red mud was investigated and chemical analyses were performed by EDAX and XRF techniques. Radioactivity of the samples was also measured with gamma spectroscopy. The concentrations of elemental ...
Titanium alloys are characterized by poor tribological properties, and the traditional use of titanium alloys has been restricted to nontribological applications. The deposition of a well adherent diamond coating is a promising way to solve this problem. In this study, the tribological properties of diamond-coated titanium were studied using a pin-on-disk tribometer, and the results were compared with those of pure titanium and plasma nitrided titanium. The tribological behavior of pure titanium was characterized by high coefficient of friction and rapid wear of materials. Plasma nitriding improved the wear resistance only under low normal load; however, this hardened layer was not efficient in improving the wear resistance and the friction properties under high normal load. Diamond coating on pure titanium improved the wear resistance of titanium significantly. Surface profilometry measurement indicated that little or no ...
Permalloy (Ni{sub 80}Fe{sub 20})/Cu multilayered nanowires (NWs) were electrodeposited using a template directed method from sulfate baths via pulse potential technique. Microstructures and compositions of the nanowires were characterized using various microscopy and spectroscopy techniques. To synthesize compositionally uniform nanowires with high efficiency, new sulfate baths with a high content of Ni{sup 2+} were developed. The effects of deposition potential and concentration of metal ions were optimized to reduce composition inhomogeneity and incorporation of copper in the permalloy layers. Composition of the NiFe layers was found to be close to 20 at% Fe with a maximum of 5 at% Cu. TEM analysis indicated that individual nanowires exhibit distinct and coherent layering structure with rough and wavy interfaces. A synthesized single nanowire was also AC dielectrophoretically assembled across the microfabricated gold electrodes for subsequent ...
The use of n-alkanethiolate self-assembled monolayers on gold has blossomed in the past few years. These systems have functioned as models for common interfaces. Thiolate monolayers are ideal because they are easily modified before or after deposition. The works contained within this dissertation include interfacial characterization (inbred reflection absorption spectroscopy, ellipsometry, contact angle, scanning probe microscopy, and heterogeneous electron-transfer kinetics) and various modeling scenarios. The results of these characterizations present ground-breaking insights into the structure, function, and reproducible preparation of these monolayers. Surprisingly, three interfacial properties (electron-transfer, contact angle, and ellipsometry) were discovered to depend directly on the odd-even character of the monolayer components. Molecular modeling was utilized to investigate adlayer orientation, and suggests that ...
Laser-assisted processing techniques, utilized to produce fine, metal grid patterns for high-efficiency solar cells, are being investigated, developed, and characterized. The work performed in the third quarter of this contract is detailed here. A preliminary economic evaluation has yielded the conclusion that laser-assisted pyrolysis of spun-on silver neodecanoate is the most promising of all the metallization techniques being investigated in this contract. Early adhesion problems have been solved by optimizing deposition parameters. Linewidth studies have been carried out as a function of laser power, scan speed, and film thickness. Preliminary solar cells have been fabricated and characterized using this metallization scheme. Silver neodecanoate films have also been decomposed using a pulsed uv laser and metal mask. A detailed study of the various models of localized surface temperature rise in silicon due to laser ...
Ferroelectric thin films such as BST, PZT and PLZT are extensively being studied for the fabrication of DRAMS since they have high dielectric constant. The large and reversible remnant polarization of these materials makes it attractive for nonvolatile ferroelectric RAM application. In this paper we report the characterization of Ba0.7Sr0.3TiO3 (BST) thin films grown by pulsed laser ablation on oxide electrodes. The structural and electrical properties of the fabricated devices were studied. Growth of crystalline BST films was observed on La0.5Sr0.5CoO3 (LSCO) thin film electrodes at relatively low substrate temperature compared to BST grown on PtSi substrates. Electrical characterization was carried out by fabricating PtSi/LSCO/BST/LSCO heterostructures. The leakage current of the heteros...
Because the number of neutrons and gamma rays and the energy spectrum of particles from spontaneous fission are well characterized for {sup 252}Cf, it can be used as a timed source of fission neutrons and gamma rays. The first such usage incorporated a {sup 252}Cf source into gas scintillators. This paper describes a timed source of neutrons and gamma rays made by depositing {sup 252}Cf on one electrode of a parallel plate ionization chamber that can then be used for determining detection-system characteristics. The emission time of neutrons from spontaneous fission has also been determined by recording the emission time of prompt gamma rays from a {sup 252}Cf source (not incorporated into a detector) adjacent to the surface of a solid or liquid scintillator. This well characterized source of neutrons can thus be used as a randomly pulsed source for a variety of applications. This paper illustrates the use of this type of ...
The titanium stabilized austenitic steel similar to the type of 321 is sensitive to the stress corrosion crackingunder horizontal steam generator operating condition. SCC was observed under crevice corrosion parameters and has resulted in the transgranular or intergranular cracking at the both, components primary collectors and heat exchange tubes. The crevice environment is characterized by aggressive impurities and 'non aggressive' compounds. Sulfates and chlorides as aggressive species and silicates and alumino-silicates as 'non aggressive' species on the other hand are present in significant amount in the crevice environment under operating condition. Local water chemistry parameters were evaluated with MULTEQ Code. As input data the measured operational values of local and bulk environments have been used. The determined parameters were compared with the results of thread hole environment analyses and tube surface ...
Continental facies of Scythian-early Anisian age (Buntsandstein) of East of the Paris Basin form the underground gas storage reservoir exploited by Gaz de France in the area of Nancy (east of France). An accurate sedimentological study and the application of Genetic Stratigraphy principles lead to the understanding of the deposition of fluvial, which form the reservoirs, and to the reconstruction of their geometries. The subsurface data are calibrated on outcrops. Three types of fluvial systems (braided, sinuous to straight and anastomosed) are defined. A special focus on anastomosed channels permits to differentiate a proximal and a distal facies. Study of laterally continuous outcrops induces recurrent cycles of thickness, velocity and time variations (few tens to hundred ka). These correspond to the highest frequence stratigraphic units, i.e. parasequences or genetic units. Maximum of channel and levee presentation occurs during base-level rise: base-level fall ...
Within the Williston basin, thickness variations of the Prairie Formation are common and are interpreted to originate by two processes: differential accumulation of salt during deposition and differential removal of salt by dissolution. Unambiguous evidence for each process is rare because the Prairie/Winnipegosis interval is seldom cored within the US portion of the basin. Therefore, indirect methods, using well logs, provide the principal method for identifying characteristics of the two processes. The results of this study indicate that the two processes can be distinguished using correlations within the Prairie Formation. Several regionally correlative brining-upward and probably shoaling-upward sequences occur within the Prairie Formation. Near the basin center, the lowermost sequence is transitional with the underlying Winnipegosis Formation. This transition is characterized by thinly laminated basal carbonates that become increasingly ...
The preparation and performance of membranes for application to hydrogen separation from coal-derived gas is described. The membrane material investigated was dense amorphous silica deposited on a suitable support by chemical vapor deposition (CVD). Two types of support materials were pursued. One type consisted of a two-layer composite, zeolite silicalite/{alpha}-Al{sub 2}O{sub 3}, in the form of tubes approximately 0.7 cm in diameter. The other type was porous glass tubes of diameter below 0.2 cm. The first type of support was prepared starting from {alpha}-Al{sub 2}O{sub 3} tubes of 1{micro}m mean pore diameter and growing by hydrothermal reaction a zeolite silicalite layer inside the pores of the alumina at the OD side. After calcination to remove the organic template used in the hydrothermal reaction, CVD was carried out to deposit the final silica layer. CVD was carried out by alternating exposure of the surface with ...
An outcrop-based study combining detailed lithofacies analysis with high-resolution sequence stratigraphy in the Paradox Basin, southwestern United States. has shown that complex lateral and vertical facies variations occur in relatively consistent and predictable patterns. Large-scale facies shifts of several kilometers occur across major sequence boundaries whereas small-scale lateral and vertical variations develop from stacking of individual cycles. Understanding of vertical stacking patterns and lateral distribution of facies in outcrop can be directly applied to both three-dimensional distribution of reservoir facies in the subsurface as well as the evaluation of heterogeneity within individual reservoirs. The Desert Creek and Ismay intervals of the Paradox Formation (Pennsylvanian) exposed along the San Juan River in southeastern Utah are characterized by high-frequency cyclic repetition of carbonate and siliciclastic facies controlled primarily by 4th and ...
Nylon 6 and nylon 66 films have been treated with aqueous sulfonated aromatic compound (SAC) solutions at concentrations ranging from 0.005 to 1.0 wt%. SAC uptakes at different treatment concentrations were measured and found to follow a BET isotherm. The surface morphologies of nylon film samples, including the original and SAC-treated films, have been characterized by atomic force microscopy (AFM). For untreated nylon 6 and nylon 66 films, AFM images show a randomly distributed fibrillar surface structure. Characteristic widths of fibrils in the nylon 66 and 6 films were 150-225 and 75-150 nm, respectively. For SAC-treated nylon films, the AFM images revealed that the surfaces of the films became covered with nodule-like features having a diameter range of 25-60 nm. AFM analysis provides evidence that SAC treatment deposited a surface coating on nylon films. AFM images of SAC-treated nylon films suggest a mechanism for stain resistance in ...
Successful interface engineering requires compositional and electronic material characterization as a prerequisite for understanding and intentionally generating interfaces in photovoltaic devices. The paper gives an overview with several examples, all referring to Cu(In,Ga)(S,Se){sub 2} ('CIGSSe')-based solar cells, with an emphasis on characterization using highly specialized methods, such as elastic recoil detection analysis, X-ray emission spectroscopy and photoelectron spectroscopy using synchrotron and ultraviolet light for excitation, inverse photoemission spectroscopy and Kelvin probe force microscopy. First, the determination of the depth profile of the band gap energy E{sub g} in the absorber layer is demonstrated. The modification of E{sub g} towards both interfaces is discussed in terms of beneficial electronic effects. Next, the interface between absorber and buffer layers with alternative and promising non-toxic ...
The Maybell uranium mill tailings site is 25 miles (mi) (40 kilometers [km]) west of the town of Craig, Colorado, in Moffat County, in the northwestern part of the state. The unincorporated town of Maybell is 5 road mi (8 km) southwest of the site. The designated site covers approximately 110 acres (ac) (45 hectares [ha]) and consists of a concave-shaped tailings pile and rubble from the demolition of the mill buildings buried in the former mill area. Contaminated materials at the Maybell processing site include the tailings pile, which has an average depth of 20 feet (ft) (6 meters [m]) and contains 2.8 million cubic yards (yd{sup 3}) (2.1 million cubic meters [m{sup 3}]) of tailings. The former mill processing area is on the north side of the site and contains 20,000 yd{sup 3} (15,000 m{sup 3}) of contaminated demolition debris. Off-pile contamination is present and includes areas adjacent to the ...
In this paper, we discuss the large--time behavior of solution of a simple kinetic model of Boltzmann--Maxwell type, such that the temperature is time decreasing and/or time increasing. We show that, under the combined effects of the nonlinearity and of the time--monotonicity of the temperature, the kinetic model has non trivial quasi-stationary states with power law tails. In order to do this we consider a suitable asymptotic limit of the model yielding a Fokker-Planck equation for the distribution. The same idea is applied to investigate the large-time behavior of an elementary kinetic model of economy involving both exchanges between agents and increasing and/or decreasing of the mean wealth. In this last case, the large-time behavior of the solution shows a Pareto power law tail. Numerical results confirm the previous analysis.
The conductive ultra thin films were fabricated from mixed monolayers containing stearic acid and Head-to-Tail poly(3-alkylthiophene). These films exhibited well-defined layered structures as determined by optical absorption and X-ray diffraction measurements. The UV-Vis absorption spectra of these films showed lower energy absorption shifts of 48 nm from that of the random poly(3-alkylthiophene)/stearic acid LB films. The blue shift of absorption maximum of the LB film is attributed to the increase of {pi}-conjugation length caused by no steric hindrance of alkyl side chains. The conductivity of the Head-to-Tail poly(3-hexylthiophene)/stearic acid LB films was greatly improved in the range of 67-100 S/cm. (orig.)
The results of an investigation into tailed nuclei (TN) and features of dose dependence on frequency of the binuclear cells with TN in human lymphocyte cultures by cytogenetic block method upon X-ray radiation dose are presented. The frequencies of metaphases with dicentric and ring chromosomes are investigated concurrent with TN formed upon completion of first postradiation mitosis. Frequency of the appearance of binuclear cells with nuclei having outgrowth into the cytoplasmic space and arises after first mitosis in human lymphocyte culture is linear-square dependent on the X-irradiation at doses from 0.0 to 4.0 Gy. Positive correlation between frequency of cells with tailed nuclei and frequency of metaphases of first mitosis having dicentric and rings was established. Apparently, formation such TN is connected with dicentric and rings
The US NRC, in its Generic Environmental Impact Statement on uranium milling has specified that the radon flux escaping a uranium mill tailings pile will be reduced to pCi/m/sup 2/ s by application of covering layers of soils and clays. These covers present a radon diffusion barrier, which sufficiently increases the time required for radon passage from the tailings to the atmosphere to allow for decay of /sup 222/Rn within the cover. The depth of cover necessary to reduce the escaping radon flux to the prescribed level is to be determined by calculation, and requires precise knowledge of the radon diffusion coefficient in the covering media. A Radon Attenuation Test Facility was developed to determine rates of radon diffusion through candidate cover materials. This paper describes this facility and its application for determining the influence of physical properties of the soil column on the radon diffusion coefficient.
Atmospheric pressure plasma enhanced chemical vapour deposition system is built. The electrical and optical characteristics of the APPECVD system is given. The system is used to deposit conductive polymers and nano composites onto glass and metal surfaces. The morphological, optical, chemical and electrical characteristics of deposited surfaces are investigated using SEM, AFM four probe deposition purposes. The photovoltaic applications of plasma deposited polymers and nonconsumption are compared with deposited with electrochemical methods show different results. The electrical, chemical and morphological structures of the samples will be given.
San Francisco Bay has been contaminated historically by mercury from mine tailings as well as contemporary industrial sources. Native Spartina foliosa and non-native S....Full Text Available
... and sperm showed an association with the oviduct epithelial tissue. Estimate of sperm storage duration At ASDP in ... Sperm heads show no particular association with the epithelial tissue. enlarge fig...
Striated muscle fibers from the body and tail myotomes of a fish, the black Mollie, have been examined with particular attention to the sarcoplasmic reticulum (SR) and transverse tubular (or T) system....Full Text Available
The ascending and descending relationships of visual cortex in Trichosurus were determined using HRP and autoradiographic methods. The visual thalamus, LGNd and LP, was found to project to three cytoarchitecturally...Full Text Available
An attempt was made to minimize the channeling tail by implantation along a random equivalent direction following a careful alignment of the target. In order to analytically determine the random equivalent directions, critical angles for channeling were mapped on a stereogram. Boron ions with energies of 17 and 45 keV are implanted along specified directions determined from the map. The depth distribution of the dopant is profiled by SIMS and the effects of water orientation upon the channeling tail are noted. Industrial common use of a 7/sup 0/ tilt is not optimum. However, implantation with the wafer tilted at 5.5 +/- 0.5/sup 0/ from the surface normal and rotated at 7.0 +/- 0.5/sup 0/ from a (100) plane shows the least channel-tail compared to implantation along other directions. Rapid thermal annealing (RTA) is a promising annealing method for shallow junction formation. Transient enhanced diffusion of implanted boron ...
An attempt was made to minimize the channeling tail by implantation along a random equivalent direction following a careful alignment of the target. In order to analytically determine the random equivalent directions, critical angles for channeling were mapped on a stereogram. Boron ions with energies of 17 and 45 keV are implanted along specified directions determined from the map. The depth distribution of the dopant is profiled by SIMS and the effects of water orientation upon the channeling tail are noted. Industrial common use of a 7"0 tilt is not optimum. However, implantation with the wafer tilted at 5.5 +/- 0.5"0 from the surface normal and rotated at 7.0 +/- 0.5"0 from a (100) plane shows the least channel-tail compared to implantation along other directions. Rapid thermal annealing (RTA) is a promising annealing method for shallow junction formation. Transient enhanced diffusion of implanted boron is observed. Two ...
The composition of the extracellular matrix (ECM) was examined in the developing lens and optic cup (stages 11-16) of the long-tailed monkey (Macaca fascicularis) using peroxidase immunocytochemistry....Full Text Available
We report here on a case of localized lymphoid hyperplasia of the pancreas in a 70-year-old man which manifested as double lesions (uncinate process and tail) in the organ. The lesions were incidentally...Full Text Available
The fossil record is a unique source of evidence for important evolutionary phenomena such as transitions between major clades. Frustratingly, relevant fossils are still comparatively rare, most transitions...Full Text Available
A 23-year-old woman presented to our hospital with nonspecific pain in the abdomen. She underwent radiological investigations, which revealed a solid and cystic mass in the tail end of the pancreas....Full Text Available
Acid mine drainage is a serious environmental problem caused by the oxidation of sulfide minerals that releases highly acidic, sulfate, and metals-rich drainage. In this study, alkaline industrial wastes were mixed with acid mine tailings in order to obtain neutral conditions. A series of column leaching tests were performed to evaluate the behavior of reactive mine tailings amended with alkaline-additions under dynamic conditions. Column tests were conducted of oxidized mine tailings combined with cement kiln dust, red mud bauxite, and mixtures of cement kiln dust with red mud bauxite. The pH results show the addition of 10% of alkaline materials permits the maintenance of near neutral conditions. In the presence of 10% alkaline material, the concentration of toxic metals such as Al, Cu, Fe, Zn are significantly reduced as well as the number of viable cells (Thiobacillus ferrooxidans) compared to control samples.
This regulatory guide describes methods acceptable to the NRC staff for calculating radon fluxes through earthen covers and for calculating the resulting minimum cover thickness needed to meet NRC and EPA standards. The guide also suggests methods for obtaining the various parameters used in calculating the radon fluxes and earthen cover thicknesses and suggests default values for certain parameters. This regulatory guide is applicable to active uranium tailings sites. The NRC staff is using the methods stated in this guide as a basis for review and concurrence of DOE remedial action plans for inactive sites. The guidance is intended to be used for calculating radon flux attenuation by earthen uranium mill tailings covers. The parameter values and examples presented are limited to earthen cover materials, but the diffusion theory and the methods presented are also applicable to man-made materials. Detailed supporting information for calculating ...
This regulatory guide describes methods acceptable to the NRC staff for calculating radon fluxes through earthen covers and for calculating the resulting minimum cover thickness needed to meet NRC and EPA standards. The guide also suggests methods for obtaining the various parameters used in calculating the radon fluxes and earthen cover thicknesses and suggests default values for certain parameters. This regulatory guide is applicable to active uranium tailings sites. The NRC staff is using the methods stated in this guide as a basis for review and concurrence of DOE remedial action plans for inactive sites. The guidance is intended to be used for calculating radon flux attenuation by earthen uranium mill tailings covers. The parameter values and examples presented are limited to earthen cover materials, but the diffusion theory and the methods presented are also applicable to man-made materials. Detailed supporting information for calculating ...
Cytokinesis in animal and fungal cells utilizes a contractile actomyosin ring (AMR). However, how myosin II is targeted to the division site and promotes AMR assembly, and how the AMR coordinates with...Full Text Available
The complete RNA genome of the avian nephritis virus (ANV) associated with acute nephritis in chickens has been molecularly cloned and sequenced. Excluding the poly(A) tail, the genome comprises 6,927...Full Text Available
A hitherto unrecognized variant of solid-pseudopapillary tumor (SPT) of the pancreas is reported. The tumor presented in the pancreatic tail of a 44-year-old female patient. It was a well-defined, solid...Full Text Available
... on the presence of leukocytes in the mammary epithelial tissue [11], temporal differentiation of the epithelial cells during ... of the gland and were separated from the epithelial tissue by bundles of co...
A new analysis is developed for long secondary photocurrent transients which gives the distribution of trapped holes in valence band tail states. Thermally assisted tunneling to dangling bonds is implicated as the rate limiting step in hole-recombination. Light-soaking causes the energetically deeper hole traps with the longer residence times to be lost first and in the same number as would be expected for the increase in dangling bonds; This result supports a model which has hole trapping in valence tail states as a precursor to light induced dangling bonds.
The use of uranium mill tailings in the foundations of dwellings has resulted in indoor radon progeny concentrations and gamma exposures in excess of levels presently allowed for the general public. An account is given of the applications of an epoxy coating on the indoor faces of the concrete foundations of three buildings in Grand Junction, Colorado. Epoxy barriers were shown to be effective for preventing radon influx into structures. Gamma exposure rates must be analyzed to ensure that buildup behind the barrier will not introduce an unacceptable gamma exposure level. The use of a sealant is especially economical in situations where structural integrity may be jeopardized by physical removal of uranium mill tailings. (author).
Five nomographs have been prepared that facilitate the estimation of cover thickness and cover material volume for the Uranium Mill Tailing Remedial Action Program. Key parameters determined include the cover thickness with either a surface radon flux or a boundary radon air concentration criterion and the total volume of cover material required for two different treatments of the edge slopes. Also included in the engineering guide are descriptions and representative values for the radon source term, the diffusion coefficients and the key meteorological parameters. 16 refs., 7 figs., 2 tabs.
Taconite tailings and their component asbestiform minerals in Lake Superior water had no demonstrable effect on the chronic toxicity of cadmium to the flagfish, Jordanella floridae. Maximum acceptable toxicant concentrations determined in life cycle tests, where effects on survival, growth, reproduction, and bioconcentration were used as endpoints, were between 3.3 to 7.4, 3.0 to 6.5, and 3.4 to 7.3 micrograms cadmium/liter at 0.004, 0.08, and 0.95 mg/liter taconite tailings concentrations, respectively.
According to the present concept, the low and intermediate level wastes generated during the Cernavoda NPP operation will be disposed in a near surface repository. The Saligny site, placed in the NPP protected area, has been proposed for their disposal. Geologically, the main components of this site are the quaternary loess, the Precambrian and Pre-quaternary clays, the Eocene and Barremian limestone. Hydrologically, the site can be divided into a vadose zone down to 45-50 m and three distinct aquifers, two of them in the limestone beds and the third in the lenses of sand and limestone existing in the pre-quaternary clay layer. A large research program for site characterization was initiated in 1996. At present, the site characteristics requested for safety analysis have been experimentally measured on soil samples or calculated by different computer programs. Hundreds of experimental values of the density, porosity, hydraulic conductivity, soil-water retention, ...
The environmental impacts of uranium mining and milling activities are of great concern in many countries for the last three decades. These impacts range from the creation of massive stockpiles of radioactive and toxic waste rock and sand-like tailings to serious contamination of surface and groundwater with radioactive and toxic pollutants, and releases of conventional, toxic and radioactive air pollutants. Uranium mining is also associated with high concentrations of highly toxic heavy metals, which are a major source of surface and groundwater contamination. Depending upon the hydraulic properties of the fractures involved, contaminated ground water may be transported many miles from its point of origin before feeding into an aquifer. Tailings pond may contaminate the groundwater regime by continuous seepage and leaching of radionuclides and other toxic metals due to interaction of rain water through the tailings ponds. ...
This work showed the formation of phospholipid vesicle coating on inorganic sericite surface with characterization by combining electron microscopy of FE-SEM, TEM, AFM, and qualitatively evaluated the coated phospholipid vesicle by XPS as a function of etching time. The possibility of phospholipid vesicle mobility on the surface was restrained by the chelation effect of magnesium cation. The stabilization properties of phospholipid vesicles on sericite surface were demonstrated by the various concentration of magnesium cation. The presence of magnesium was found to have a much more pronounced influence on the lipid deposition process. The Mg cation plays an important role for attaching the phospholipids with optimum concentration of 7 mM. Totally, the phospholipid vesicles coating on inorganic powder could be useful for bio-related fields such as cosmetics and drug delivery system as the key functional compounds. We hope this basic result lead ...
The improvement of the ecological conditions at waste storing reservoirs is an important task of the restoration activity at Production Association (PA) ``Mayak`` (South Urals). The radionuclides mostly {sup 90}Sr, {sup 137}Cs, and chemical pollutants deposited in the reservoir water and in the bottom sediment are very dangerous sources for the contamination of Techa River below the reservoirs and the contamination of groundwater in the surrounding formations. The spreading of radioactive contaminants has both hydrogeological and the chemical features. The thermodynamic approach used to account for physical-chemical interactions between water and the bed rocks based on Gibbs free energy minimization of multicomponent system (H-O-Ca-Mg-K-Na-S-Cl-C-Sr) permitted the authors to calculate the corresponding ionic and complex species existing in the solutions, and to characterize the processes of precipitation and dissolution. The model takes into ...
In this study, WO{sub 3} thin films were grown on glass substrates using an aqueous solution containing tungstate (NH{sub 4}){sub 2}WO{sub 4} as precursor. The substrate temperature incremented from 250 to 500 deg. C, by steps of 50 deg. C. The structural properties were investigated using XRD, atomic force microscopy and scanning electronic microscopy techniques. Microprobe analyses showed that a balanced stoichiometric composition was obtained for thin films prepared at T{sub s} = 350 and 400 deg. C. The X-ray diffraction analyses showed different structure crystallography in function of the substrate temperature. Moreover, films deposited at 400 deg. C were annealed in air for 2 h at 450 and 500 deg. C, respectively and the structural changes due to heat treatment were studied. Finally, the optical properties of these films were carried out using optical measurements of transmittance T({lambda}) and reflectance R({lambda}) spectra in 300-1800 nm domain. The ...
In this study, WO3 thin films were grown on glass substrates using an aqueous solution containing tungstate (NH4)2WO4 as precursor. The substrate temperature incremented from 250 to 500 deg. C, by steps of 50 deg. C. The structural properties were investigated using XRD, atomic force microscopy and scanning electronic microscopy techniques. Microprobe analyses showed that a balanced stoichiometric composition was obtained for thin films prepared at Ts = 350 and 400 deg. C. The X-ray diffraction analyses showed different structure crystallography in function of the substrate temperature. Moreover, films deposited at 400 deg. C were annealed in air for 2 h at 450 and 500 deg. C, respectively and the structural changes due to heat treatment were studied. Finally, the optical properties of these films were carried out using optical measurements of transmittance T(?) and reflectance R(?) spectra in 300-1800 nm domain. The refractive and absorption indexes, n and k were ...
The U.S. Department of Energy - Office of Industrial Technology (DOE) has an objective to increase energy efficient and enhance competitiveness of American metals industries. To support this objective, ALCOA Inc. entered into a cooperative program to develop spray forming technology for aluminum. This Phase II of the DOE Spray Forming Program would translate bench scale spray forming technology into a cost effective world class process for commercialization. Developments under DOE Cooperative Agreement No. DE-FC07-94ID13238 occurred during two time periods due to budgetary constraints; April 1994 through September 1996 and October 1997 and December 1998. During these periods, ALCOA Inc developed a linear spray forming nozzle and specific support processes capable of scale-up for commercial production of aluminum sheet alloy products. Emphasis was given to alloys 3003 and 6111, both being commercially significant alloys used in the automotive industry. The report reviews research ...
Hybrid organic-inorganic coatings with phosphonate functionalities have been synthesized and evaluated as prospective surface treatments for magnesium materials. These coatings have been processed via a sol-gel route by hydrolysis and condensation of a mixture of diethylphosphonatoethyltriethoxy-silane and tetraethoxy-silane with variable molar ratios. The coatings morphology and the surface chemistry at the coating/substrate interface have been characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, "3"1P nuclear magnetic resonance spectroscopy, and time-of-flight secondary ion mass spectrometry. The corrosion protection performance of the coatings deposited on magnesium alloy AZ31B has been examined by a group of electrochemical techniques including potentiodynamic polarization and electrochemical impedance spectroscopy. In addition, a scanning Kelvin probe technique has been used to investigate interfacial ...
Zinc oxide thin films were obtained by laser ablation of a Zn target in oxygen reactive atmosphere, the oxygen being supplied either by a standard gas inlet valve or from a radio-frequency (rf) oxygen plasma. Pt-coated silicon and MgO were used as substrates. The influence of the deposition parameters as laser wavelength (266, 355, 1064 nm), laser fluence (1.5-20 J/cm2) and oxygen pressure (1-60 Pa) was studied. The influence of the rf plasma beam addition on the morphological proprieties of zinc oxide films was particularly investigated, simultaneously with several configurations of the direction of the ablation plasma, the rf plasma beam and the substrate. The obtained films, with thicknesses in the range of 50 nm to 1 ?m have been characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), transmission electron microscopy (TEM).
There has been considerable interest in producing and studying nanoparticle materials because of the effect of size on their structure, physical and chemical structure. Most studied nanoparticle semiconductors belong to the II-VI group, as they are relatively easy to synthesize and are generally prepared as particulates or in thin film form. Among II-VI compounds, CdS is one of the most studied materials. There are different ways to synthesize CdS nanoparticles such as colloidal particles, chemical decomposition, sol-gel, gas evaporation, magnetron sputtering, electrostatic deposition, and etc. {gamma}-irradiation is one of the effective methods for synthesis of nanomaterials. These nonomaterials have been extensively used in the preparation of nanocrystalline metals, metal oxides, and metal-polymer composites. However, The preparation of CdS nanoparticle and CdS/ polyacrylonitrile nanocomposite by {gamma}-irradiation method at room temperature and ambient ...
Nano-sized zinc oxide was synthesized and deposited onto cellulosic fibers using the sol-gel process at ambient temperature. The prepared materials were characterized using several techniques including scanning electron microscopy, transmission electron microscopy, diffuse reflectance spectroscopy, X-ray diffraction and thermogravimetric analysis. X-ray diffraction studies of the ZnO-coated fiber indicate formation of the hexagonal crystal phase which was satisfactory crystallized on the fiber surface. The electron micrographs show formation of zinc oxide nanoparticles within 10-15 nm in size which have been homogeneously dispersed on the fiber surface. The prepared materials show significant photocatalytic self-cleaning activity, which was monitored by diffuse reflectance spectroscopy. The photoactivity was studied upon measuring the photodegradation of methylene blue and eosin yellowish under UV-Vis irradiation. The photocatalytic activity of ...
One of the most challenging topics in the area of organic electronic devices is the growth of transparent electrodes onto flexible polymeric substrates that will be characterized by enhanced conductivity in combination with high optical transparency. An essential aspect for these materials is their synthesis and/or microstructure which define the transparency, the stability and the interfacial chemistry which in turn determine the performance and stability of the organic electronic devices, such as organic light emitting diodes, organic photovoltaics, etc. In this work, we will discuss the latest advances in the growth of organic (e.g. PEDOT:PSS) and inorganic (e.g. zinc oxide-ZnO, indium tin oxide-ITO) conductive materials and their deposition onto flexible polymeric substrates. We will compare the optical, structural, nano-mechanical and nano-topographical properties of the inorganic and organic materials and we investigate the effect of ...
Thin Fe and Ta layers of 30-45 nm thickness, deposited via magnetron sputtering on Si (1 0 0) substrates, were bombarded at room temperature with 100 keV Ar{sup 1+} or Ar{sup 8+} or with 250 keV Xe{sup 1+} or Xe{sup 19+} ions in order to test the influence of the ion charge state on the surface sputtering and interface mixing. The samples were characterized by means of Rutherford backscattering at 0.9-3.0 MeV {alpha}-particle energy, time-of-flight elastic recoil detection analysis with a 53 MeV {sup 127}I{sup 10+} beam and atomic force microscopy. No influence of the charge state on the sputtering and athermal mixing rate was observed in the case of the Ta/Si system. However, in the case of the Fe/Si system, the ion charge was observed to have an influence on the mixing rate.
This thesis studied the petrology and sequence stratigraphy of the Hoadley barrier, a Glauconitic member in the Westerose field in Alberta. The unit contains gas reserves in an extensive northeast-southwest trending marine complex. A high resolution sequence stratigraphic model was used to understand the facies development of the unit and the diagenetic pathway of the strata. Six high frequency sequences were identified within the Glauconitic member. Each are separated from one another by surfaces of incision or subaerial exposure which sometimes coincide with a flooding surface and erosion. This thesis provided a petrographic characterization and depositional history of each of the 6 sequences. Reservoir quality is developed within the relatively quartz-rich foreshore facies of the G2B sandstones. The G3 chert litharenite to sublitharenite sandstones are excellent gas producers because of their coarser grain size and secondary porosity. The ...
Alkaline fuel cells (AFCs) provide a less corrosive environment and can provide higher electrode reaction kinetics than proton exchange membrane fuel cells (PEMFCs). The alkaline media also allows for the replacement of platinum (Pt) based electrocatalysts with non-Pt electrocatalysts. Studies have shown that palladium (Pd) and silver (Ag) form a homogenous solid solution with a face-centred cubic structure within a large range of temperatures. This study described the results of an oxygen reduction reaction (ORR) on lead-silver (Pd-Ag) alloy electrodes in alkaline media. The reaction was compared with Pd and Ag electrodes. The alloys were synthesized as thin films using a sequential electroless deposition of Pd and Ag on stainless steel discs followed by an annealing procedure in an Ar stream. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to characterize catalyst structure, ...
Abnormal intracellular deposition of aggregated ?-synuclein is the characteristic feature of a number of neurological disorders, including Parkinson's disease (PD). Although ?-synuclein is typically known as a cytosolic protein, a small amount is secreted by exocytosis in both monomeric and aggregated forms. The extracellular forms of ?-synuclein in human body fluids, such as cerebrospinal fluid (CSF) and blood plasma, might be a diagnostic target for PD and related diseases. Here, we characterized a new set of monoclonal antibodies against ?-synuclein, and using different combinations of antibodies, we established ELISA systems to specifically detect human ?-synuclein, mouse and human ?-synuclein together, and multimeric forms of ?-synuclein in biological samples. By employing the Tyramide signal amplification method, the sensitivity of the assay was significantly improved to detect a concentration as low as ?12.5 pg/ml. These assays might be ...
In the present study, new light weight nano-composites (AZ31B-3.3Al2O3-Cu) based on magnesium alloy AZ31B are developed using disintegrated melt deposition technique. Microstructural characterization studies revealed grain refinement and significant increase in amount of second phases as a result of increasing presence of copper. All the samples exhibited minimal porosity and good matrix-second phase interfacial integrity. The results also showed that addition of both nano-Al2O3 and Cu led to a simultaneous improvement in 0.2% yield compressive strength (0.2%YCS), ultimate compressive strength (UCS) and work of fracture (WoF) of the AZ31B magnesium alloy while failure strain was marginally affected. The results of this study clearly illustrate the capability of AZ31B-Al2O3-Cu formulations ...
Research was conducted at Pacific Northwest Laboratory to develop high photosensitivity adaptive optical elements utilizing ion implanted lanthanum-doped lead-zirconate-titanate (PLZT). One centimeter square samples were prepared by implanting ferroelectric and anti-ferroelectric PLZT with a variety of species or combinations of species. These included Ne, O, Ni, Ne/Cr, Ne/Al, Ne/Ni, Ne/O, and Ni/O, at a variety of energies and fluences. An indium-tin oxide (ITO) electrode coating was designed to give a balance of high conductivity and optical transmission at near uv to near ir wavelengths. Samples were characterized for photosensitivity; implanted layer thickness, index of refraction, and density; electrode (ITO) conductivity; and in some cases, residual stress curvature. Thin film anti-ferroelectric PLZT was deposited in a preliminary experiment. The structure was amorphous with x-ray diffraction showing the beginnings of a structure at ...
Coaxial nanocables with a single-crystalline zinc telluride (ZnTe) nanowire core and an amorphous silicon oxide (SiO_x) shell have been synthesized via a simple one-step chemical vapor deposition (CVD) method on gold-decorated silicon substrates. The single-crystal ZnTe nanowire core is in zinc-blende structure along the [111] direction, while the uniform SiO_x shell fully covers the core with no observable pin-hole or crack. Formation mechanisms of the ZnTe-SiO_x nanocables are discussed. The ZnTe nanowire core shows p-type electrical properties while the SiO_x shell acts as an effective insulating layer. The ZnTe-SiO_x nanocables may have potential applications in nanoscale devices, such as p-type FETs and nanosensors.
Neutron semiconductor detectors for neutron counting and neutron radiography have an increasing importance. Simple silicon neutron detectors are combination of a planar diode with a layer of an appropriate neutron converter such as 6LiF. These devices have limited detection efficiency of not more than 5%. The detection efficiency can be increased by creating a 3D microstructure of dips, trenches or pores in the detector and filling it with a neutron converter. The first results related to the development of such devices are presented. Silicon detectors were fabricated with pyramidal dips on the surface covered with 6LiF and then irradiated by thermal neutrons. Pulse height spectra of the energy deposited in the sensitive volume were compared with simulations. The detection efficiency of these devices was about 6.3%. Samples with different column sizes were fabricated to study the electrical properties of 3D structures. Charge collection efficiencies in silicon ...
The thesis deals with methods of describing the reservoir rock in central oil and gas fields on the Norwegian continental shelf. Methods of enhancing the level of recovery are dealt with. Following topics are given: Sand body dimensions and infill sequences of stable, humid-climate delta plain channels; minipermeameter-based study of permeability trends in channel sand bodies; significance of tidal cyclicity for modelling of reservoir heterogeneities in the lower Jurassic Tilje Formation, mid-Norwegian shelf; geometry and facies of large-scale flow units in fluvial-dominated fan-delta-front sequences; quantified fluvial architecture in ephemeral stream deposits of the Esplugafreda Formation (Palaeocene), Tremp-Graus Basin, northern Spain; the Safari project - collection and storage of field analogue data for quantitative reservoir modelling; sedimentary architecture of field analogues for reservoir information (SAFARI): a case study of the fluvial Escanilla ...
Feasibility of depositing continuous films of nano-porous alumino-silicates, primarily zeolites and MCM-41, on metallic and non-metallic substrates was examined with an aim to develop membranes for separation of gaseous mixtures and also for application as hydrogen storage material. Mesoporous silica was deposited in-side the pores of these nano-porous disks with an aim to develop membranes for selective separations. Our study involves supported zeolite film growth on substrates using in-situ hydrothermal synthesis. Faujasite, Silicalite and Mesoporous silica have been grown on various metallic and non-metallic supports. Metallic substrates used for film growth included anodized titanium, sodium hydroxide treated Titanium, Anodized aluminum, and sintered copper. A non-metallic substrate used was nano-porous aluminum oxide. Zeolite film growth was characterized using Scanning Electron Microscope (AMRAY 1820) and High ...
The lower continental slope of the northwestern Gulf of Mexico is characterized by a hummocky topography with shallow salt masses interspersed by numerous salt-withdrawal basins containing thick Plio-Pleistocene and older sediments. Analysis of over 7500 km of multichannel seismic reflection data from the Keathley Canyon Area and vicinity defined the Wisconsinan-Holocene sequence and its seismic facies. In interbasinal areas and in the southern part of the study area where salt is shallow, the Wisconsinan-Holocene sequence consists mainly of low-amplitude (LA) facies underlain by strong basal-reflection (SBR) facies. The LA facies occasionally show subtle onlaps against SBR facies and grade upward into a draping pattern. Onlapping LA facies are interpreted to be a lowstand systems tract deposited by widespread low-energy turbidity currents. Draping LA facies at the top may consist of hemipelagic or pelagic sediments. The SBR facies are ...
The oxide colloidal route, developed in the laboratory for mono-metallic catalysts, consists in preparing a metallic oxide hydro-sol which leads to the supported catalyst after deposition onto a support and an activation stage. In this work, this method has been adapted to the preparation of alumina supported bimetallic Pd-Sn catalysts to determine its interest for the control of the properties of the bimetallic phase (size, composition and structure). In the preliminary study concerning tin oxide sols, SnO{sub 2} (size=2,3 nm) and Sn{sub 6}O{sub 4}(OH){sub 4} (size = 25 nm) nano-particles were synthesized by neutralization respectively for tin(IV) and tin(H). The control through the pH of the aggregation of the PdO and SnO{sub 2} particles revealed that increasing oxide solubility promotes integral re-dispersion of the oxide particles. To synthesize oxide bimetallic sols, three strategies were defined. Copolymerization (formation of a mixed oxide nano-sol by cross ...
This study was carried out mainly to produce uranium trioxide (UO_3), with the standard of commercial specifications from rock phosphate deposits in eastern part of Nuba mountains, south Kurdufan state. A simplified hydrometallurgical procedure has been adopted for production of yellow cake from the ore. Elemental analysis has shown that the ore is rich in Ca and deficient in elements of potential interest such as Fe, Cu and Zn. Uranium content in ore, phosphoric acid and purified yellow cake (UO_3) obtained with different precipitants was analyzed using alpha-spectrometry. On the average, the activity concentration of uranium in ore corresponds to 82 #+-# 24 ppm (0.10%). From the data of pregnant liquor, it was observed that the addition of KCIO_3 as an oxidant improves the dissolution of uranium from the ore by almost 20%. Data has also indicated that the yellow cake purified by hydrogen peroxide has higher concentration of uranium by 44.5% over the one purified ...
A method for detecting electrons emitted as secondary particles by photon incidence to a specimen, as well as a method of using the photons emitted by electron incidence as detecting particles are explained. Pd-Si(100)2{times}1 system is adopted for a case study of using photo-electron spectroscopy where synchrotron emitted light in soft X-ray region is used as the incident light. Pd atoms are deposited little by little on clean Si surface to investigate the electron structure of the surface, and the interface electron structure after bonded formation of Pd(thin film)-Si(substrate) is estimated. Radiation soft X-ray spectroscopy is employed to observe the real state of the bonded interface of Pd(thin film)-Si(substrate) prepared by depositing Pd film in a short period of time. In the case of radiation soft X-ray spectroscopy with electron beam excitation, bonded system of thin film and substrate can be investigated by nondestructive analysis ...
This article considers the fundamentals of what happens in asolid when it is impacted with a medium energy gallium ion. The study ofthe ion/sample interaction at the nanometer scale is applicable to mostfocused ion beam (FIB) based work even if the FIB/sample interaction isonly a step in the process, e.g., micromachining or microelectronicdevice processing. Whereas the objective in other articles in this issueis to use the FIB tool to characterize a material or to machine a deviceor transmission electron microscopy (TEM) sample, the goal of the FIB inthis article is to have the FIB/sample interaction itself become theproduct. To that end, the FIB/sample interaction is considered in threecategories according to geometry: below, at, and above the surface.First, the FIB ions can penetrate the top atom layer(s) and interactbelow the surface. Ion implantation and ion damage on flat surfaces havebeen comprehensively examined; however, FIB applications require thefurther ...
Computed tomography would be a better method to detect and characterize a Thorotrast-induced liver tumour. The selective opacification of the RES by Thorotrast creates an intrinsic opacification of the liver similar in effect to contrast agents being evaluated for liver CT, such as ethoioidized oil emulsion. The computed tomographic appearance of Thorotrast-associated cholangiocarcinoma is usually a large, inhomogenous mass composed of disordered area of tissue of high density due to Thorotrast deposits, and of very low density. Thorotrast-induced cholangiocarcinoma originates in the peripheral biliary tree suprounding the highest mean concentration of Thorotrast deposition, so that visible soft tissue masses in the higher density spots in the liver are not produced in the early stage. The tendency for the opacity of the liver to decrease slowly with time and result in an uneven trabeculation and high density spots suggests ...
The advantage of high-resolution sequence stratigraphy, which takes base-levels as reference, is that it can be applied to continental depositional basins controlled by multiple factors and can effectively improve the accuracy and resolution of sequential stratigraphic analysis. Moreover, the principles of base-level cycles are also suitable for analyzing sequential stratigraphy in continental coal-bearing basins because of their accuracy in forecasting distribution of coal measures. By taking the Dongsheng coalfield in the Ordos basin as an example, the extensive application of base-level cycles in exploration and exploitation of coal is analyzed. The result shows that the Yan'an formation in the Dongsheng area is a long-term base-level cycle which is bordered by nonconformities and made up of five mid-term cycles and 13 short-term cycles. The long-term cycle and the mid-term cycles are obvious in comparison with a transverse profile. The episodic coal ...
The study of the intrinsic behavior of high transition temperature copper-oxide superconductors (HTSC) has proven to be challenging because of the extreme sensitivity of their transport properties on material quality. These compounds are characterized by a high degree of structural and electrical anisotropy, and a very short superconductive coherence length of the same order as the size of the crystalline unit cell (~5-30 A). As a result, microscopic defects such as oxygen vacancies, cationic disorder, and the presence of minute impurities have a significant effect on electrical transport in these materials. Therefore, much effort has been expended in synthesizing sizable samples that are homogeneous, well characterized, and emenable to the study of the anisotropic properties of the HTSC. We have demonstrated that thin films of HTSC compounds such as rm YBa_2Cu_3O_{7 -delta}, which is a 92 K superconductor, can be synthesized easily by a ...
Additional measurements have been made of deposition and retention of inhaled radioactively labeled iron oxide aerosols generated by a spinning top aerosol generator.
The Maybell uranium mill tailings site is 25 miles (mi) (40 kilometers [km]) west of the town of Craig, Colorado, in Moffat County, in the northwestern part of the state. The unincorporated town of Maybell is 5 road mi (8 km) southwest of the site. The site is 2.5 mi (4 km) northeast of the Yampa River on relatively flat terrain broken by low, flat-topped mesas. U.S. Highway 40 runs east-west 2 mi (3.2 km) south of the site. The designated site covers approximately 110 acres (ac) (45 hectares [ha]) and consists of a concave-shaped tailings pile and rubble from the demolition of the mill buildings buried in the former mill area. The site is situated between Johnson Wash to the east and Rob Pit Mine to the west. Numerous reclaimed and unreclaimed mines are in the immediate vicinity. Aerial photographs (included at the end of this executive summary) show evidence of mining activity around the Maybell site. Contaminated materials at the Maybell ...
Seafloor mapping and morphometric analysis of landslide scars can provide useful insights for marine geo-hazard assessment, as demonstrated by several studies performed on different geological settings. The availability of high-resolution multibeam bathymetry and long-range side scan sonar data on the submarine portions of Stromboli Volcano allow us to map and characterize the main mass-wasting features that affect, on the whole, about the 90% of its submarine extension. In particular, two main kinds of tsunamigenic landslides have been recognized and analyzed. Large-scale sector collapses (Fig. 1) are catastrophic events that mobilize 1-2 cubic kilometers of material, generating huge tsunami waves that may affect Stromboli and propagate in surrounding areas; related hazard is not very high, as they show recurrence periods of some (or more) thousand years. Conversely, medium-scale landslides are more hazardous, as they occur at higher frequency with respect to the ...
This phase report summarizes the results of field investigations conducted in 1992 at Technical Area 21 of Los Alamos National Laboratory, as prescribed by the RCRA Facility Investigation work plan for the Technical Area 21 operable unit (also known as OU 1106). This phase report is the last part of a three-part phase report describing the results of field work conducted in 1992 at this operable unit. Phase Report lA, issued on l4 June l993, summarized site geologic characterization activities. Phase report 1B, issued on 28 January 1994, included an assessment of site-wide surface soil background, airborne emissions deposition, and contamination in the locations of two former air filtration buildings. The investigations assessed in Phase Report 1C include field radiation surveys and surface and near-surface sampling to characterize potential contamination at 25 outfalls and septic systems listed as SWMUs in the RFI work ...
Plasma-deposited thin films prepared at room temperature, ranging from 46 to 250 A of PdAu on #approx#45-50 A Si-oxide and Si-oxynitride films grown on Si wafers were studied. Grazing incidence X-ray diffraction, X-ray reflectivity, and XPS depth profile techniques were used to characterize the thin films. A reactive interface involving Pd- and Au-silicides is formed, linking the thin film to the Si-oxide and Si-oxynitride films: a small fraction of Pd and Au atoms from PdAu migrate into the Si substrate, first penetrating the oxide layer, and the small fraction of Si atoms from the oxide layer migrate into the PdAu film and form a silicide interlayer consisting of a reactive interface made up of mixtures of Au- and Pd-silicides interspersed within the matrix of PdAu and substrate. The concentration profiles of these silicides have a maximum at the interface with decay on both sides. The density and the face-centered cubic (fcc) lattice ...
This report attempts to bring together available information on the coal deposits of Antarctica and discuss factors that would be involved if these deposits were to be explored and mined. Most of the reported principal coal deposits in Antarctica lie generally within the Transantarctic Mountains: the majority are of Permian age and are present in the Victoria Group of the Beacon Supergroup. Several other deposits have been recorded in East Antarctica and in the Antarctic Peninsula, including minor occurrences of Mesozoic and Tertiary coal and carbonaceous shale.
In order to apply chemical-looping combustion to a practical power plant, carbon deposition on the solid particle is one of the key problems to be overcome. Six kinds of solid particles were examined to clarify the kinetic behavior of carbon deposition. The effects of the solid composition, feed gas composition, and reaction temperature on carbon deposition were investigated by thermogravimetrical reactor on the basis of NiO/YSZ particle. From the viewpoints of both reactivity and resistance against carbon deposition, the particle of NiO mixed with YSZ (i.e., yttria-stabilized zirconia) was found to be a good candidate for chemical-looping combustion. It has been observed that carbon deposition could be completely avoided with very low concentration of water vapor. By means of a proposed model, the condition that carbon deposition would be avoided was ...
The possibilities to grow isolated structures of complex oxides by pulsed laser deposition through stencils were investigated. A stencil consisting of a SiN membrane with apertures of several hundred nanometers embedded in a Si chip is placed in front of a heated substrate (up to 750 degrees Celsius). Deposition through these apertures results in resistless, direct patterning by local deposition of complex oxides like ferroelectric Lead Zirconate Titanate. The created isolated structures were analyzed by AFM imaging. Under-deposition, in this work called broadening, is inevitable during stencil deposition and is depending on deposition parameters, especially pressure. Different causes of broadening are mapped and discussed.
In an effort to minimize the distortion of bearing steel rings during the production process, 100Cr6 steel billets are spray formed with a unique cooling control system to control the cooling and solidification behavior of the deposits. Effects of heating around the deposits, gas cooling at the substrate bottom and the gas flow over the deposits are investigated both by numerical simulation and experiment. Porosity profiles and microstructures of spray formed bearing steel are examined and evaluated. The investigation results show that the thermal boundary conditions of the deposits play important roles on the cooling and solidification behavior of the deposits, especially at the deposit periphery. Porosity in the 100Cr6 bearing steel deposit can be reduced significantly with the special cooling control system.
One of the main problems facing the mining sector is the production of acid mine drainage (AMD), which is caused by the oxidation of sulphide minerals in the presence of water. AMD can have a detrimental effect on the environment. One solution is to use soil covering over the materials that cause acid to limit the gas flux by diffusion. A capillary barrier effect is generated by using various layers of different types of soil. In the composite system till and clay normally form the basis of the fine material layer. The use of low sulphide tailings to replace the use of fine grained soil was studied to evaluate its effectiveness. Following both in situ and laboratory experiments spread over an eight-year period, the results indicated that an effective method to limit the oxygen flux and generation of AMD is the use of non-acid generating tailings as the moisture retaining layer. The main concepts that form the basis of the study, analysis and ...
Mining operations took place at the Sullivan Mine, located at Sullivan, Abitibi, Quebec between 1930 and 1967 and generated large quantities of tailings. These tailings now represent a waste rock pile in the shape of a delta on the shore of De Montigny Lake. The area covers approximately 50 hectares. When the waste rock pile was first established, several terrestrial and aquatic ecosystems were lost forever. In addition, the very nature of the tailings, combined to the action of the wind and lake, further slow the natural site regeneration. The Ministere des Ressources naturelles du Quebec (Quebec Natural Resources Department) asked Les Consultants en Environnement Argus to prepare a site remediation plan to stimulate the natural regeneration of the ecosystems. It would enable the local fauna to resume its occupation of the territory, while ensuring its proper integration in the environment. The authors described in detail ...
Open pit oil sands mining involves the disturbance of thin overburden covers of Boreal forest lands that must be returned to equivalent land capability after mining activities have ceased. Before mining starts, any wetlands are drained, timber is harvested, and peat, topsoils and subsoils are stockpiled for later use. This article discussed wetland reclamation activities conducted by Suncor Energy at its open pit mining operations. Research facilities were constructed in order to determine if wetlands constructed with consolidated tailings (CT) and pond effluent water (PEW) were able to support a sustainable vegetation community. Thirty-three cat-tail plots were established at the facility as well as unplanted plots in order to determine how quickly natural establishment occurred. Shoreline plug transplants and transplants from a natural saline lake were also introduced. Within 5 years, over 23 plant species had naturally colonized the CT ...
Pacific Northwest Laboratory (PNL) is investigating the use of a rock armoring blanket (riprap) to mitigate wind and water erosion of an earthen radon suppression cover applied to uranium mill tailings. Because the radon suppression cover and the tailings must remain intact for up to 1000 years or longer, the riprap must withstand natural weathering forces. This report is a review of information on rock weathering and riprap durability. Chemical and physical weathering processes, rock characteristics related to durability, climatic conditions affecting the degree and rate of weathering, and testing procedures used to measure weathering susceptibilities have been reviewed. Sampling and testing techniques, as well as analyses of physical and chemical weathering susceptibilities, are necessary to evaluate rock durability. Many potential riprap materials may not be able to survive 1000 years of weathering. Available techniques for durability ...
In an effort to develop cost-efficient techniques for remediating uranium contaminated groundwater at DOE Uranium Mill Tailing Remedial Action (UMTRA) sites nationwide, Sandia National Laboratories (SNL) deployed a pilot scale research project at an UMTRA site in Durango, CO. Implementation included design, construction, and subsequent monitoring of an in situ passive reactive barrier to remove Uranium from the tailings pile effluent. A reactive subsurface barrier is produced by emplacing a reactant material (in this experiment various forms of metallic iron) in the flow path of the contaminated groundwater. Conceptually the iron media reduces and/or adsorbs uranium in situ to acceptable regulatory levels. In addition, other metals such as Se, Mo, and As have been removed by the reductive/adsorptive process. The primary objective of the experiment was to eliminate the need for surface treatment of tailing pile effluent. ...
YBa_2Cu_3O_7_-_x thick films have been deposited on silver sheets and MgO single crystals by spray pyrolysis. Film texture is related to film thickness and sintering temperature. The X-ray intensity ratio of the 005 peak to the 110 peak is higher for thin films deposited at the higher temperatures. However, elevated temperatures promote copper diffusion and second-phase formation in films deposited on silver. Films deposited on MgO can have larger grain sizes and are more oriented than those deposited on silver.
Energy deposition process by relativistic fast electrons produced by ultra-intense laser pulses is discussed. The process is calculated with a two dimensional Fokker-Planck simulation code including binary and collective collisions coupled with electromagnetic field. We focused on Velocity Distribution Function (VDF) dependence in the simulation. The results show that the spread angle of the fast electrons distribution affects energy deposition area and deposited energy is concentrated in the vicinity of the propagation axis of the fast electrons. It may be also suggested that self-pinch effect of a fast electron beam causes large deposition energy. (author)
A new magnetic macroparticle filter design consisting of two 90{sup o} filters forming an S-shape is described. Transport properties of this S-filter are investigated using Langmuir and deposition probes. It is shown that filter efficiency is product of the efficiencies of two 90{sup o} filters and the deposition rate is still acceptably high to perform thin film deposition. Films of amorphous hard carbon have been deposited using a 90{sup o} filter and the S-filter, and macroparticle content of the films are compared.
Results are given for deep-level petroleum and gas drilling probes in various coastal zones of Southern Sakhalin covering the Poronai depression and the Aniv Bay trough. The exploratory probes indicate that the Middle Miocence deposits of the Boundary trough contain commercial-size deposits of petroleum, that commercial-size gas deposits are in the upper Myocene deposits of the Aliv Bay trough, and that the upper Cretaceous and Cenozoic deposits of the eastern section of Southern Sakhalin lack folded deformations. 7 references, 2 figures.
The understanding of fission product deposition in realistic steam generator conditions is needed for release estimates in PSA studies, and for the design of efficient accident management procedures. This is considered very important because primary-to-secondary leakages risk dominant sequences in many plants. Furthermore, the decay heat of the fission product deposits adds to the thermal load to the steam generator tubes also in other sequences, especially in case of cold leg leakages. This brings out the concern of induced steam generator tube ruptures in cases, where the steam generators are initially intact. The experimental data showed that the highest deposited fraction within the tubes were found in cases with lowest flow velocities. The minimum value of the deposited fraction was observed at intermediate flow velocities. With these relatively low Reynolds numbers, the results calculated with ...
The understanding of fission product deposition in realistic steam generator conditions is needed for release estimates in PSA studies, and for the design of efficient accident management procedures. This is considered very important because primary-to-secondary leakages risk dominant sequences in many plants. Furthermore, the decay heat of the fission product deposits adds to the thermal load to the steam generator tubes also in other sequences, especially in case of cold leg leakages. This brings out the concern of induced steam generator tube ruptures in cases, where the steam generators are initially intact. The experimental data showed that the highest deposited fraction within the tubes were found in cases with lowest flow velocities. The minimum value of the deposited fraction was observed at intermediate flow velocities. With these relatively low Reynolds numbers, the results calculated with ...
ObjectiveExtended periods of muscle disuse, physical inactivity, immobilization, and bedrest result in a loss of muscle mass and a decrease in muscle force, which are accompanied by an increase in oxidative stress. We investigated the effects of the intake of green tea catechins on unloading-induced muscle dysfunction in tail-suspended mice. MethodsTen-week-old male BALB/c mice were fed a purified control diet or a diet containing 0.5% tea catechins for 14 d. Thereafter, the mice were subjected to continuous tail suspension for 10 d. On the final day, muscle mass, contractile force production, antioxidant potential, and carbonylated protein levels were evaluated. ResultsHind limb unloading caused a loss of soleus muscle weight and muscle force. Intake of tea catechins significantly inhibit...
This paper first introduces the calculating method of radium specific activity to determine the radon emanation rate of tailing of uranium mine No. 794, the method needs two parameters: radon emanation coefficient and radon diffusion coefficient. According to the measured results of parameters and the contrast between radium specific activity of indoor chemical analysis of field sample and field gamma-ray spectra, the authors discuss the variation rules and characteristics of radon emanation coefficient and radon diffusion coefficient, and the best climate and seasons for measuring these parameters in northern China, and finally summarize the characteristics of this method through analyzing measured results. (authors)
Abstract Despite reduced sympathetic activity below the level of a spinal cord injury (SCI), venoconstriction during autonomic dysreflexia increases venous return to the heart. Here, contractions of isometrically mounted tail veins from rats with spinal transection at T4 performed 8???10 weeks earlier are compared with those from sham-operated rats. After SCI, lumen diameter was reduced by ?30% and the contractions evoked by electrical stimulation of the perivascular axons were larger than control. This augmentation of neurovascular transmission was not associated with enhanced sensitivity to ?-adrenoceptor agonists or to adenosine-5?-triphosphate (ATP) although contractions to depolarization with K+ were larger after SCI. The percentage reduction in nerve-evoked contraction after SCI prod...
From their genesis by weathering and sedimentation, bauxites, the principal aluminium ores, contain appreciable amounts of uranium and thorium. High resolution gamma spectrometry with a high purity germanium detector was used for an analysis of four industrially used bauxites from Gondama, Sierra Leone; Boke, Guinea; Weipa, Queensland, Australia; Gove, Northern Territory, Australia. Significant differences in uranium to thorium ratios and in activities of the uranium and thorium daughters were observed for the four bauxites. It was found that the bauxite from Gondama, Sierra Leone has an activity of only 10% compared with the others. Red mud tailings from such a bauxite may well be used as an additive to bricks, which is now illegal for normal red mud from more active bauxites. (author).
From their genesis by weathering and sedimentation, bauxites, the principal aluminium ores, contain appreciable amounts of uranium and thorium. High resolution gamma spectrometry with a high purity germanium detector was used for an analysis of four industrially used bauxites from Gondama, Sierra Leone; Boke, Guinea; Weipa, Queensland, Australia; Gove, Northern Territory, Australia. Significant differences in uranium to thorium ratios and in activities of the uranium and thorium daughters were observed for the four bauxites. It was found that the bauxite from Gondama, Sierra Leone has an activity of only 10% compared with the others. Red mud tailings from such a bauxite may well be used as an additive to bricks, which is now illegal for normal red mud from more active bauxites. (author).
Magnetic fields appear to be a generic feature of the early universe and are a natural source of secondary CMB non-Gaussianity. In recent years the statistical nature of the stresses of a primordial magnetic field has been well studied. In this paper we confirm and extend these studies at one- and two-point level, and present analytical results for a wide range of power-law spectra. We also consider two non-power law cases of interest: a blue spectrum with an extended damping tail on small scales, which could be generated by the non-linear mixing of density and vorticity; and a red spectrum with a damping tail on large scales. We then briefly consider the CMB impacts that result from such fields. While this paper focuses on the one- and two-point moments, the techniques we employ are designed to ease the analysis of the full bispectra induced by primordial magnetic fields.
We present a theoretical study of the resonant interaction between dynamical localized states (discrete breathers) and linear electromagnetic excitations (EE's) in Josephson junction ladders. By making use of direct numerical simulations we find that such an interaction manifests itself by resonant steps and various sharp switchings (voltage jumps) in the current-voltage characteristics. Moreover, the power of ac oscillations away from the breather center (the breather tail) displays singularities as the externally applied dc bias decreases. All these features may be mapped to the spectrum of EE's that has been derived analytically and numerically. Using an improved analysis of the breather tail, a spectroscopy of the EE's is developed, The nature of breather instability driven by localized EE's is established.
A growing concern about the consumer behavior in Internet economy has spurred the study of Material Flow, resulting in a unique type of consumer behavioral analysis. This research proposes an enhanced conceptual model for Personalized Material Flow Services for consumer behavior. In the era of Internet information technology, customer?s taste tends to be personalized for their market demand. It is observed that there are number of ?Long Tail? phenomena in several successful e-commerce business cases. However, the Long Tail phenomenon is an open question for our research in terms of its role in e-commerce marketing. In the proposed model-X-Party Personalized Material Flow Services, three elements are discussed. They are ?providing?, ?locating? and ?obtaining? based on X-Party Material Flow ...
This paper evaluates the performance of asphalt membranes by examining the chemical and permeability changes experienced by the asphalt during aging tests. The aging process was accelerated by exposing the asphalt to elevated temperatures, high oxygen concentrations, and increased strengths of aqueous oxidizing agents. The synergistic effects of the variables are evaluated by using a fractional factorial experimental design. The installation costs for a catalytically airblown asphalt liner are roughly half that of the typical polymeric materials, and also less than the rubberized asphalt membrane. The results of the initial accelerated aging tests of the asphalt membranes indicate that this material will provide stable, long-term leachate isolation in a mill tailings environment.
Thin films of new metastable materials from the system Ti-B-C-N were deposited on metallic substrates by d.c. magnetron sputtering in different Ar+N{sub 2} atmospheres. The multiphase compound targets used were based on various compositions on the TiC-TiB{sub 2} and TiB{sub 2}-C tie lines of the Ti-B-C phase diagram. The structure and chemical composition of the films were characterized by electron microprobe analysis, depth profiling Auger electron spectroscopy, X-ray diffraction and transmission electron microscopy. The hardness, critical load of failure and the tribological behavior of the coatings were investigated. Superhard single-phase crystalline metastable Ti-B-C-N layers with hardness values exceeding 5000 HV{sub 0.05} and extremely low sliding wear against 100Cr6 and Al{sub 2}O{sub 3} counterparts could be produced by reactive sputtering of various TiC-TiB{sub 2} targets in Ar+N{sub 2} atmospheres with low nitrogen flows. In the case ...
This study was carried out mainly to produce uranium trioxide (UO_3), matching standard commercial specification from rock phosphate deposits in Uro and Kurun at eastern part of the Nuba Mountains. A simplified hydrometallurgical procedure has been adopted for production of yellow cake from the ore. The powdered ore sample was leached with concentrated H_2SO_4 acid with and without addition of KCIO_3 as an oxidant. The crude yellow cake was precipitated from the resulting green solution of phosphoric acid as Na_2U_2O_7 and (NH_4)_2U_2O_7 and subsequently purified by TBP extraction (tributylphosphate) and hydrogen peroxide as UO_4.2H_2O. TBP purified product was dried and calcined to UO_3 whereas UO_4.2H-2O was dried and reduced to UO_3 by Na_2S_2O_3. Prior to precipitation of crude yellow cake, Fe in the phosphoric acid solution was precipitated using magnesia. Elemental analysis has shown that the ore is rich in Ca and deficient in elements of potential interest ...
Supercritical CO2 is used as a new solvent for immersion deposition, a galvanic displacement process traditionally carried out in aqueous HF solutions containing metal ions, to selectively develop metal films on featured or non-featured silicon substrates. Components of supercritical fluid immersion deposition (SFID) solutions for fabricating Cu and Pd films on silicon substrates are described along with the corresponding experimental setup and procedure. Only silicon substrates exposed and reactive to SFID solutions can be coated. The highly pressurized and gas-like supercritical CO2, combined with the galvanic displacement property of immersion deposition, enables the SFID technique to selectively deposit metal films in small features. SFID may also provide a new method to fabricate palladium silicide in small features or to metallize porous silicon.
A methodology for the determination of the rare earth elements in uranium oxides by ion microprobe has been set up on a Cameca ims-3f instrument. An uranium oxide reference material from a syn-metamorphic uranium deposit related to albitisation has also been developed for this type of analysis. Applications of the methodology are presented for a series of uranium oxides selected from some major uranium deposit types: from the world's highest grade unconformity-related uranium deposit from the Athabasca Basin (Saskatchewan, Canada; the Shea Creek and the McArthur River examples), a perigranitic vein-type deposit (Pen Ar Ran, Vendee, France) and a volcanic caldera-related deposit (Streltsovkoye, Transbaikalia, Russia). Each type of uranium deposit appears to have a specific REE signature. Al...
In this paper we demonstrate the electrodeposition of nickel, a common ferromagnetic material, in various magnetically desirable shapes including nanowires, nanoparticles and highly faceted shells. In order to obtain three dimensional mesostructures, the electrochemical deposition of nickel was performed on highly oriented pyrolytic graphite (HOPG) under different electrolyte composition and deposition potential conditions. Under potentiostatic deposition at one distinct potential negative with respect to the reversible potential of nickel, three stages of nucleation and growth take place leading to a complex morphology of deposits. However, dual-pulse potential deposition and electrodeposition in low pH solutions causing hydrogen evolution, lead to nickel deposits in the form of nanowires...
A ternary nickel-base alloy Ni-W-B has been developed for surface corrosion and wear resistance to replace chromium plating, which uses environmentally hazardous solutions. The deposition conditions used an alkaline bath and insoluble anodes. The as-deposited alloy typically contains 40 wt% W and 1 wt% B and has an amorphous or partially amorphous structure. These deposits compare favorably with hexavalent chromium deposits in throwing power, color uniformity, and reflectivity. The corrosion resistance of Ni-W-B alloy was compared with hexavalent chromium and electroless nickel deposits in a variety of acids, including hydrochloric, sulfuric, fluoroboric, and phosphoric. In all cases, best results were obtained with the Ni-W-B deposits.
This thesis deals with the evaluation of Solar Grade Silicon (SoG-Si) purified by different techniques, and also the fabrication and characterization of high efficiency and advanced bifacial solar cells. In the beginning of Chapter 1, various SoG-Si production methods relevant for this work are qualitatively described. The three feedstock materials used in this work are from the Fluidized Bed Reactor (FBR) process, metallurgical feedstock-I and feedstock-II process. In metallurgical feedstock-I, the lifetime of the minority charge carriers in multicrystalline silicon (mc-Si) samples at the grain boundaries are found to be higher than the grains themselves possibly due to lower resistivities in the grain boundaries. The efficiency of the best solar cell obtained using the mc-Si metallurgical feedstock-I is 16.1%. It has been identified that the fast light induced degradation, whose magnitude is lower than that of a reference cell suggests the formation of a B-metal ...
TiO{sub 2} is a vital material in several technologies including, photocatalysis, gas sensing, biomaterials and optical coatings. Among the several crystal structures of this oxide, rutile has the highest density and microhardness, the highest index of refraction and the highest temperature stability. The processing of dense polycrystalline materials often includes the addition of a liquid-forming phase at higher temperatures. This technique is known as liquid-phase sintering and has been studied extensively. Rutile boundaries containing an amorphous phase have been used to study boundary migration and grain-boundary grooving. Visible-light (VLM), scanning electron (SEM) and transmission electron microscopy (TEM) in addition to electron-backscatter diffraction (EBSD) and a focused-ion beam (FIB) tool were used to characterize boundary migration in rutile. EBSD analysis was carried out on a Philips XL30 FEG SEM equipped with a DigiView 1612 high-resolution, ...
Volume one contains calculations for: embankment design--embankment material properties; Union Carbide site--bedrock contours; vicinity properties--origin of contamination; North Continent and Union Carbide sites contaminated materials--excavation quantities; and demolition debris--quantity estimate.
Volume four contains calculations for: Borrow areas--site evaluation; temporary facilities--material quantities; embankment quantities--excavation and cover materials; Burro Canyon site excavation quantities--rippable and unrippable materials; site restoration--earthwork quantities and seeding; and bid schedule quantities and material balance.
The report gives results of a survey of the flue gas desulfurization (FGD) systems at Kansas Power and Light Co.'s Lawrence Power Station. The systems utilize boiler injection of pulverized limestone, followed by tail-end wet scrubbing: unit 4, with a net...
There are about fifty SET domain protein methyltransferases (PMTs) in the human genome, that transfer a methyl group from S-adenosyl-L-methionine (SAM) to substrate lysines on histone tails or other peptides. A number of structures in complex with cofactor, substrate, or inhibitors revealed the mechanisms of substrate recognition, methylation state specificity, and chemical inhibition. Based on these structures, we review the structural chemistry of SET domain PMTs, and propose general concepts towards the development of selective inhibitors.
This volume contains appendices D6 through D8 containing laboratory test data: from MK-F investigation, 1987, Old Rifle and New Rifle sites; on bentonite amended radon barrier material; and from MK-F investigation, 1987, riprap tests.
Reclamation of copper mine tailings in a cost effective, successful, and sustainable manner is an ongoing area of evaluation in the arid southwest. A study was initiated in September, 1996 near Hayden, Arizona to evaluate the use of municipal biosolids for reclaiming acidic copper mine tailings (pH of 2.5 to 4.0). The main objectives of the study were to (1) define an appropriate level of biosolids application for optimum plant growth, and (2) evaluate the effects of green waste and lime amendments. The experiment was a randomized complete block design with four biosolid rates of 20, 70, 100 and 135 dry tons/acre, three amendment treatments (none, green waste, and green waste plus lime); with three replications. Non-replicated controls (no treatment, green waste only and lime only) were included for comparison. Shortly after biosolids incorporation to a depth of 10--12 inches, composite soil samples (0--12 inches) of each plot were taken. ...
Naturally Occurring Radioactive Material (N.O.R.M.) occurs in most soil and rock, and by mining and mineral processing, some of the radionuclides are significantly enhanced. An in-situ gamma-ray detector called M.E.D.U.S.A., has been used to produce a map of relative activity concentrations in a gold mine tailings dam on the Witwatersrand in South Africa. A CsI(Na) scintillation detector is used in this system. M.E.D.U.S.A. spectra obtained from the survey were analyzed using the Full-Spectrum Analysis (F.S.A.) procedure to compute the {sup 40}K, {sup 238}U and {sup 232}Th activity concentrations. The activity concentrations are used with global positioning data (G.P.S.) to produce the concentration maps. A hyper-pure germanium gamma-ray detector (Hp Ge) was used to measure gamma-rays from the naturally occurring nuclides for soil samples taken at different points on the site to calibrate the M.E.D.U.S.A. system. Radon soil gas measurements were performed at ...
Histone H3 mRNAs were found in polyA(+) fractions of total RNA prepared from alfalfa plants, calli and somatic embryos. The sequence analysis of cDNAs revealed the presence of a polyA tail on independent...Full Text Available
Muon captures by nucleon pairs via meson-exchange currents produce a high energy excitation tail in heavy nuclei. The muon induced fission by these excitations is calculated in several subactinide nuclei with high threshold fission barriers. The probability for delayed fission ranges from 4 x 10"-"5 to 4 x 10"-"3 for the isotopes considered. (orig.).
The waste tail gas fuel emitted from refinery plant in Taiwan e.g. catalytic reforming unit, catalytic cracking unit and residue desulfurization unit, was recovered and reused as a replacement fuel. In this study, it was slowly added to the fuel stream of a heater furnace to replace natural gas for powering a full-scale distillation process. The waste tail gas fuel contained on average 60 mol% of hydrogen. On-site experimental results show that both the flame length and orange-yellowish brightness decrease with increasing proportion of waste gas fuel in the original natural gas fuel. Moreover, the adiabatic flame temperature increases as the content of waste gas fuel is increased in the fuel mixture since waste gas fuel has a higher adiabatic flame temperature than that of natural gas. The complete replacement of natural gas by waste gas fuel for a heater furnace operating at 70% loading (i.e. 3.6 x 10{sup 7} kcal/h of combustion capacity) will ...
Hepatitis C virus (HCV) nonstructural protein 5B (NS5B), the viral RNA-dependent RNA polymerase (RdRp), is a tail-anchored protein with a highly conserved C-terminal transmembrane domain (TMD) that...Full Text Available
The ntpJ gene, a cistron located at the tail end of the vacuolar-type Na+-ATPase (ntp) operon of Enterococcus hirae, encodes a transporter...Full Text Available
A general expression for the current-density distribution of a focused-ion beam (FIB) in the chromatic-aberration region is set up in the form of a definite integral. With the experimentally obtained ion-energy distribution of a liquid-metal ion source, its contribution to the FIB current-density distribution is estimated. Calculated results explain the wide-exponential tail of a FIB.
A general expression for the current-density distribution of a focused-ion beam (FIB) in the chromatic-aberration region is set up in the form of a definite integral. With the experimentally obtained ion-energy distribution of a liquid-metal ion source, its contribution to the FIB current-density distribution is estimated. Calculated results explain the wide-exponential tail of a FIB.
During the past 12,000 years agricultural systems have transitioned from natural habitats to conventional agricultural regions, and recently to large areas of genetically- engineered (GE) croplands. This GE revolution occurred for cotton in a span of slightly more than a decade w...
The recently observed phenomenon of boron uphill diffusion during low-temperature annealing of ultrashallow ion-implanted junctions in silicon has been investigated. It is shown that the effect is enhanced by preamorphization, and that an increase in the depth of the preamorphized layer reduces uphill diffusion in the high-concentration portion of boron profile, while increasing transient enhanced diffusion in the tail. The data demonstrate that the magnitude of the uphill diffusion effect is determined by the proximity of boron and implant damage to the silicon surface.
Analytical relations are obtained for estimating how the distributions of temperature and heat flux vary along a steam-generating tube and how the steam-generator power output reduces due to formation and accumulation of deposits.
Analytical relations are obtained for estimating how the distributions of temperature and heat flux vary along a steam-generating tube and how the steam-generator power output reduces due to formation and accumulation of deposits.
The reactive evaporation process was successfully used to deposit films of the A-15 Nb_3Ge phase. This is the first report, to the best of our knowledge, illustrating the use of such processes for the deposition of A-15 compounds. In this process, niobium vapors from an electron-beam-heated evaporation source react with germane gas introduced into the vacuum chamber at low partial pressures (approximately 10"-"4 Torr) to produce Nb_3Ge deposits. The process variables studied were the deposition temperature, the niobium-to-germanium impingement ratio on the substrate and the plasma-enhanced deposition, in this case the activated reactive evaporation process. At low deposition temperatures (below 450"0C) the deposit is amorphous (or microcrystalline) and can be crystallized to the Nb_3Ge phase by heat treatment, e.g. at 850"0C for 1 h in ...
This report results from a contract tasking Eindhoven University of Technology as follows: The contractor will investigate the plasma treatment of surfaces and plasma enhanced deposition using EUT's cascade arc source as the basis for this effort.
Pulsed laser deposition (PLD) is known for its capacity to reproduce a target composition on a substrate. The authors have used this deposition technique to produce thin films of transition metal chalcogenides. However, the deposits were always deficient in Te relative to the starting material (composed by a refractory metal (niobium) and a chalcogene (tellurium)). Variations of the interreticular distances have been observed with respect to fluence and substrate temperature. The authors show that spatial composition of the films is determined by a degree of crystallinity of deposit and by the reaction of formation of Te{sub 2} molecule within laser induced plume. Two kinds of deposits have been obtained: Nb{sub 5}Te{sub 4}-type thin films which have a one-dimensional structure and NbTe{sub 2}-type thin films which have a two-dimensional structure. While NbTe{sub 2} films have been ...
The report is divided into six working group discussions on the following subjects: 1) Chemical and physical mechanisms in the formation of uranium mineralization, geochronology, isotope geology and mineralogy; 2) Sedimentary basins and sandstone-type uranium deposits; 3) Uranium in quartz-pebble conglomerates; 4) Vein and similar type deposits (pitchblende); 5) Other uranium deposits; 6) Relation of metallogenic, tectonic and zoning factors to the origin of uranium deposits. Each working group paper contains a short introductory part followed by a discussion by the working group members.
Adult and newborn rats were exposed to "2"3"9PuO_2 aerosols of four different size distributions. Rats of both ages were killed at intervals between 1 hr and 60 days postexposure. There were marked age- and particle-related size differences in deposition, although retention was similar throughout. The differences in deposition are attributable to relatively greater deposition of larger particles in the upper respiratory tracts of newborns.
... analyzer section for angle resolved measurements, and a thin film evaporator with a quartz crystal microbalance to measure the mass deposition. ...
A compact cesium deposition system was used for direct deposition of cesium atoms and ions onto the inner surface of the 1/3 scale Hydrogen Negative Ion Source for the LHD-NBI system. A small, well defined amount of cesium deposition in the range of 3-200 mg was tested. Negative ion extraction and acceleration were carried out both in the pure hydrogen operation mode and in the cesium mode. Single Cs deposition of 3-30 mg to the plasma chamber have produced temporary 2-5 times increases of H-yield, but the yield was decreased within several discharge pulses to the previous steady-state value. Two consecutive 30 mg depositions done within a 3-5 hours/60 shot interval, produced a similar temporary increase of H-beam, but reached a larger H-yield steady-state value. Deposition of larger 0.1-0.2 g Cs portions with a 20-120 hours/150-270 shot interval improved the ...
The hydrogen evolution reaction (HER) was studied on Ni-P{sub x} electrodes containing 8 to 16 weight percent P prepared by potentiostatic deposition. The amount of P in the alloy varied with deposition potential. The activity of the electrodes was dependent on the P concentration, and the formation of a passive film. Cyclic voltametry was used to study the removal of this film. 3 refs.
The question about expanding the boundaries of the open pit mining method is examined. The use of methods which consider the advantages of open and underground mining operations with their joint use in horizontal and evenly dipping deposits will make it possible to objectively select the mining method, to expand the range of use of open pit mining operations in the deposits of the Far North and provide an improvement in the technical and economic indicators of mineral extraction.
Amyloid-β (Aβ) deposits have been identified as key players in the progression of Alzheimer’s disease (AD). Recent evidence indicates that the deposits probably precede...Full Text Available
This report measured the rate of isothermal deposition of sub-micron particles of magnetite onto the surface of Alloy 800 at pH of 4.2-9.3 at Re=10,000 and a fluid temperature of 25C. Deposition is modelled as a two-step process, the transport of particles to the surface region followed by attachment to the surface.
X-ray ablation of material from the first wall and other components of an ICF (Inertial Confinement Fusion) chamber is a major threat to the laser final optics. Material condensing on these optics after a shot may cause damage with subsequent laser shots. To ensure the successful operation of the ICF facility, removal rates must be predicted accurately. The goal for this dissertation is to develop an experimentally validated x-ray response model, with particular application to the National Ignition Facility (NIF). Accurate knowledge of the x-ray and debris emissions from ICF targets is a critical first step in the process of predicting the performance of the target chamber system. A number of 1-D numerical simulations of NIF targets have been run to characterize target output in terms of energy, angular distribution, spectrum, and pulse shape. Scaling of output characteristics with variations of both target yield and hohlraum wall thickness are also described. ...
The identification and characterization of carbonaceous materials (CMs) that control hydrophobic organic chemical (HOC) sorption is essential to predict the fate and transport of HOCs in soils and sediments. The objectives of this paper are to determine the types of CMs that control HOC sorption in the oxidized and reduced zones of a glacially deposited groundwater sediment in central Illinois, with a special emphasis on the roles of kerogen and black carbon. After collection, the sediments were treated to obtain fractions of the sediment samples enriched in different types of CMs (e.g., humic acid, kerogen, black carbon), and selected fractions were subject to quantitative petrographic analysis. The original sediments and their enrichment fractions were evaluated for their ability to sorb trichloroethene (TCE), a common groundwater pollutant. Isotherm results and mass fractions of CM enrichments were used to calculate sorption contributions of ...
Author.Field, laboratory and market studies are a must for proper evaluation of natural resources for the mineral industry of lebanon. Sites selectively convenient to the existing major Lebanese ceramics industry centered in the Beqa'a region, were investigated as to their geology, geography and economic character. The raw materials are shales, mud stones, siltstones and other argillaceous rocks of Jurassic to Cretaceous age coming from selective sites in south and central Lebanon. The finished products include wall, floor, roofing tiles, pipes, sanitary ware, pottery and brick specimens. Differential thermal analysis, scanning electron microscopy, firing and physico-chemical tests and analyses characterized the raw materials into two major groups: the suitable are siliceous argillaceous rocks and unsuitable calcareous argillaceous rocks. The suitable group is divided into two varieties. The first is dominantly a disordered Kaolinite with low drying and firing ...
The HT-28 and 29 irradiation capsules are part of a cooperative agreement between GA and ORNL designed to evaluate irradiation performance of unbonded BISO and TRISO coated ThO_2 fertile fuel particles. The capsules will contain a total of 44 different positions uniformly divided between each capsule. The positions in HT-29 are designated for operation at 900"0C over a fast fluence increment between 5.4 to 10.7 x 10"2"1 n/cm"2 (E > 0.18 MeV)/sub HFIR/. Positions in HT-28 are divided into two sections: 11 positions at 1250"0C to receive a fast fluence exposure between 7.8 and 8.6 x 10"2"1 n/cm"2 (E > 0.18 MeV)/sub HFIR/ and 11 positions at 900"0C designed for a 4.3 to 6.9 x 10"2"1 n/cm"2 (E > 0.18 MeV)/sub HFIR/ fast fluence exposure. Both capsuls are to serve as an evaluation test to characterize the performance of BISO OPyC coatings deposited from mixed-gas (acetylene-propylene). The OPyC variables tested will be density, coating ...
We describe the growth, fabrication, and characterization of an ultraviolet (UV) photoconductive detector based on In{sub x}Al{sub y}Ga{sub 1-x-y}N quaternary alloy that is lattice matched to GaN. The detector consisted of 0.1 {mu}m In{sub x}Al{sub y}Ga{sub 1-x-y}N alloy grown on 0.5-1.0 {mu}m GaN epilayer by metalorganic chemical vapor deposition. With varying indium concentration, the cut-off wavelength of the In{sub x}Al{sub y}Ga{sub 1-x-y}N detectors could be varied to the deep UV range. The most important and intriguing result is that the responsivity of the In{sub x}Al{sub y}Ga{sub 1-x-y}N quaternary alloy exceeded that of AlGaN alloy of a comparable cutoff wavelength by a factor of five. This makes the nitride quaternary alloy very important material for solar blind UV detectors applications particularly in the deep UV range where Al rich AlGaN alloys have problems with low quantum efficiency and cracks due in part to lattice mismatch ...
We describe the growth, fabrication, and characterization of an ultraviolet (UV) photoconductive detector based on In_xAl_yGa_1_-_x_-_yN quaternary alloy that is lattice matched to GaN. The detector consisted of 0.1 #mu#m In_xAl_yGa_1_-_x_-_yN alloy grown on 0.5-1.0 #mu#m GaN epilayer by metalorganic chemical vapor deposition. With varying indium concentration, the cut-off wavelength of the In_xAl_yGa_1_-_x_-_yN detectors could be varied to the deep UV range. The most important and intriguing result is that the responsivity of the In_xAl_yGa_1_-_x_-_yN quaternary alloy exceeded that of AlGaN alloy of a comparable cutoff wavelength by a factor of five. This makes the nitride quaternary alloy very important material for solar blind UV detectors applications particularly in the deep UV range where Al rich AlGaN alloys have problems with low quantum efficiency and cracks due in part to lattice mismatch with GaN. The advantages of ...
We describe a new apparatus that combines pulsed laser excitation in a molecular beam with surface-science methods for preparation of clean single-crystal surfaces and detection of adsorbates to enable state-selected studies of gas-surface reaction dynamics. Reactant molecules are prepared in specific vibrationally excited states via overtone pumping using tunable, narrow-band laser radiation. The collision-free environment of the molecular beam prevents relaxation of the prepared molecules before impact on the target surface and enables complete control over the collision energy and incidence angle. Chemisorption products are detected after a given deposition time by Auger electron spectroscopy. To achieve sufficient beam flux of state-selected reactant molecules for product detection by standard surface-science techniques, we use a high-intensity, short-pulse molecular-beam source matched to the low duty cycle of the pulsed lasers used in our experiments. We ...
Lubricating Oil Analysis (LOA) has become an important part of a comprehensive Reliability Centered Maintenance (RCM) program. However, knowing the condition of the lubricant alone does not provide a complete description of equipment reliability. Condition monitoring for equipment can be accomplished through Wear Particle Analysis (WPA). This usually involves separating suspended materials and wear products from the lubricant by magnetic (ferrographic) means. This paper will present a simple, low-cost, alternate method of particle acquisition called Filter Patch Extraction (FPE). This method removes solids, regardless of their composition, from the lubricant by vacuum filtration and deposits them onto a filter for microscopic examination similar to that of analytical ferrography. A large filter pore size retains suspended materials and permits rapid filtration of large volumes of lubricant thereby increasing the accuracy of the wear and cleanliness profile that can ...
Reinterpretation of the South Florida basin reveals that it was a keep-up carbonate shelf during the Lower Cretaceous. Until the Cenomanian, it was connected to the Bahamas and the Cay Sal Bank north of Cuba. The Cenomanian sea level rise was at least partially responsible for the formation of the Florida Straits, isolating the platform. The combination of an abrupt worldwide rise in sea level and subsidence caused the South Florida platform to founder, ending shallow-water and evaporitic sedimentation over the majority of the shelf. The Cay Sal and Bahamian platforms remained as active shallow shelves separated by the Old Bahamas Channel. The Lower Cretaceous sediments are characterized by shallow shelf limestones, dolomites, and evaporites (mostly anhydrite). The evaporite-rich sections, originally thought to represent basinal facies, are reinterpreted as supratidal to shallow subtidal evaporites, based on examination of core and cuttings. Influx of normal marine ...
A new three-dimensional (3D) acoustic modelling method was developed using a first-order hyperbolic wave system which was solved with explicit finite dfferences. The numerical solution of the 3D wave system provides a useful method for simulating evolution of a pressure field corresponding to compressional type waves. Existing two-dimensional (2D) elastic modelling algorithms were modified and fine-tuned for computationally efficient and realistic wave propagation simulations in complex structures. An original formulation of the 3D reverse time migration method was developed which is very accurate, does not suffer from unwanted evenescent energy, can image dips beyond 90{degree}, and does not generate multiple energy. Two case studies were performed that involved steam stimulation projects in the Cold Lake deposit. Simulations were performed during different phases of the steam stimulation process to examine the relation between reservoir properties and conditions ...
Since 1984 the Environmental Protection Agency (LfU) of the State of Baden-Wuerttemberg has been investigating the heavy metal burden of earthworms from representative long-term forest observation plots. These investigations are aimed at elucidating and assessing adverse effects of pollutants on the soil biocenosis. Methods: At first only lead and cadmium were measured in the worms; in repetitive measurements over the years further metals or metalloid elements such as aluminum, arsenic, chromium, cobalt, copper, manganese, mercury, nickel, thallium, vanadium, and zinc were added to the agenda. Results and conclusion: The frequency distribution of the metals in the earthworms was characterized statistically. For the first time state-wide background values, normal values and threshold values were established for all the elements measured. A comparable study with a similar range of parameters is known neither nationally nor internationally. Time trend studies have ...
North Carolina is in the process of siting a LLRW disposal facility as the next host state for the Southwest Compact. After two years of site characterization studies at two technically challenging sites, the LLRW Management Authority (the Authority), will submit a license application for the preferred site. One potential site is in unconsolidated Tertiary and Cretaceous deposits of the inner Coastal Plain, the other in fractured sedimentary rocks of the Triassic Deep River Basin. Involved since 1986, the North Carolina Geological Survey (NCGS) provides technical advice to the Division of radiation Protection, the state regulatory agency authorized to approve or deny a license. With the multi-million dollar project behind schedule, and millions of dollars over budget, in February 1992 the Southeast Compact Commission established three project milestones (1) submit license application by December 31, 1993; (2) approve license by March 15, 1994; ...
Owing to exceptional biomolecule preservation, fossil avian eggshell has been used extensively in geochronology and palaeodietary studies. Here, we show, to our knowledge, for the first time that fossil eggshell is a previously unrecognized source of ancient DNA (aDNA). We describe the successful isolation and amplification of DNA from fossil eggshell up to 19 ka old. aDNA was successfully characterized from eggshell obtained from New Zealand (extinct moa and ducks), Madagascar (extinct elephant birds) and Australia (emu and owl). Our data demonstrate excellent preservation of the nucleic acids, evidenced by retrieval of both mitochondrial and nuclear DNA from many of the samples. Using confocal microscopy and quantitative PCR, this study critically evaluates approaches to maximize DNA recovery from powdered eggshell. Our quantitative PCR experiments also demonstrate that moa eggshell has approximately 125 times lower bacterial load than bone, making it a highly ...
This report is the 1992 annual progress report for the Energy Conversion and Storage Program, a part of the Energy and Environment Division of the Lawrence Berkeley Laboratory. Work described falls into three broad areas: electrochemistry; chemical applications; and materials applications. The Energy Conversion and Storage Program applies principles of chemistry and materials science to solve problems in several areas: (1) production of new synthetic fuels, (2) development of high-performance rechargeable batteries and fuel cells, (3) development of advanced thermochemical processes for energy conversion, (4) characterization of complex chemical processes and chemical species, and (5) study and application of novel materials for energy conversion and transmission. Projects focus on transport-process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials, and advanced methods of analysis. Electrochemistry ...
The Upper Jurassic Hith Anhydrite is a major hydrocarbon seal in the Arabian Gulf region. Outcrops, core samples from the subsurface, and the literature indicate that the Hith Formation is composed mainly of anhydrite. In most locations where a section of the Hith Formation has been measured, this unit contains less than 20% carbonate much of which is in the form of thin laminations. This lack of carbonate, locally thick layers of salt, and the predominance of anhydrite favor a playa for the setting in which this sediment was accumulated. In fact, much of the Hith has the sedimentary characteristics of the Holocene Lake MacLeod playa of Western Australia, which is dominated by layers of gypsum and halite (what little carbonate that occurs is found in layers at the base of the section). Locally the Hith appears to have accumulated in a sabkha setting, particularly toward central Abu Dhabi where it pinches out into shallow-water, and peritidal carbonate. This sabkha setting is indicated ...
[sup 13]C epitaxial diamond films have been grown on [sup 12]C-type IIb diamond substrates doped with boron, using electron assisted chemical vapor deposition. The relation between etch pits to dislocations in [sup 13]C diamond film and the broadening of the first-order Raman peak was examined. The reactant gas was [sup 13]CH[sub 4] of > 99% purity. The substrate temperature was varied from 943 to 1300 C. The uneven surface morphology was confirmed by atomic force microscopy (AFM) and laser microscopy. From 943 to 1030 C, etch pit rows along left angle 100 right angle were observed. At 991 C, the etch pit density on a row was 3300 to 5000 pits/cm. The Ar[sup +] laser beam was focused on a transparent area near the row of etch pits, where the boron impurity of the substrate is less than several 10 ppm. The first-order Raman line of [sup 13]C epitaxial diamond film was broadened to 3.6-4.0 cm[sup -1]. The line broadening was 50-90% compared with that of the [sup ...
Copper coatings deposited on Al-6061 substrates by radio frequency magnetron sputtering, to prevent the retention and permeation of energetically implanted tritium in Al-6061, were evaluated by a variety of characterization techniques. The coatings, weighing in the 0.03 to 0.088 kg/m{sup 2} range, were smooth and had a fine grain structure. They contained the intermetallic phases Cu{sub 9}Al{sub 4} and CuAl{sub 2} as well as copper. The fractions of Al and Cu in any coating increased and decreased, respectively, with increasing depth below the surface. Furthermore, the fractions of Al and Cu on the coating surface decreased and increased, respectively, with increasing coating weight. There was no texture or preferred orientation in the Cu phase of the coatings. A significant amount of oxygen was also detected at the original substrate surface. Residual stress measurements revealed that, in both Cu and CuAl{sub 2}, the stresses in the coating ...
In the geologic formation where the oil deposits are located, diverse types of rocks perform functions as structural elements, storage containers for hydrocarbon water and calorific energy, as well as impermeable barriers and transport means of the energy and the fluids. Among the most important properties that are used to describe these functions are the porosity, the permeability, the compressibility of the pores volume, the formation resistivity factor, the saturation exponent, the velocity of acoustic waves P and S, the relative permeability, the capillary pressures, the elastic constants and other mechanical properties, the thermal expansion, coefficient, the thermal conductivity, the thermal diffusivity and the specific heat. The execution of an ample variety of activities related to the stages of exploration, location, evaluation and development of the oil deposits, depends strongly on having a good knowledge of the magnitude and the ...
Understanding the erosion and deposition rates in a small watershed is important for designing soil and water conservation measures. The objective of this study is to estimate the net soil loss and gain at points with various land use types and landform positions in a small watershed in the Sichuan Hilly Basin of China by the 137Cs tracing technique. Among various land use types, the order of erosion rate was bare rock > sloping cultivated land > forest land. The paddy field and Caotu (a kind of cultivated land located at the foot of hills) were depositional areas. The erosion rate under different landform was in this order: hillside > saddle > hilltop. The footslope and the valley were depositional areas. The 137Cs technique was shown to provide an effective means of documenting the spatial distribution of soil erosion and deposition within the small watershed.
Pd/sub 2/Si formation at the Pd-Si interface induced by irradiation with ions having a wide range of nuclear energy of deposition density has been investigated. It is found that the thickness of the silicide layer formed by irradiation is proportional to the ion fluence for irradiation with ions having low energy-deposition densities, while it is proportional to the square root of the fluence for irradiation with ions having energy-deposition densities. The results indicate that Pd/sub 2/Si formation is reaction limited when the energy-deposition density at the interface is low and is diffusion limited when it is high. The results are compared with the phenomenological theory developed by Horino et al. and it is shown that such a dependence of the limiting processes on the energy depositon density is induced when the diffusion is thermally activated while the reaction at the interface is ...
A model is described for simulating thermal hydraulic and chemical conditions within fuel crud deposits. Heat transfer takes place by wick boiling in which water flows through the porous deposit and evaporates into steam at the surface of chimneys. The transport and chemistry of dissolved species within the deposit is also modelled. This chemistry includes the equilibrium chemistry of Li/boric acid species, the equilibrium chemistry of Fe/Ni species and the radiolysis chemistry of water. The unique feature of this model is that the chemistry is coupled to the thermal hydraulics via the increase in the saturation temperature with the concentration of dissolved species. This has a profound effect on evaporative heat transfer within thick deposits, leading to conditions that explain the precipitation of LiBO{sub 2} and the possible formation of bonaccordite. The model helps understand several crud scrape ...
The liquefaction reaction system of an NEDOL process coal liquefaction 1t/d PSU was opened and checked to investigate the cause of the rise of differential pressure between liquefaction reactors of the PSU. The liquefaction test at a coal concentration of 50 wt% using Tanito Harum coal was conducted, and it was found that the differential pressure between reactors was on the increase. By the two-phase flow pressure loss method, deposition thickness of deposit in pipelines was estimated at 4.4mm at the time of end operation, which agreed with a measuring value obtained from a {gamma} ray. The rise of differential pressure was caused by deposit formation in pipelines connecting reactors. The main component of the deposit is calcite (CaCO3 60-70%) and is the same as the usual one. It is also the same type as the deposit on the reactor wall. Ca in coal ash is concerned with this. To ...
Ion bombardment during deposition can significantly modify the film properties. In the partially ionized beam deposition, ions derived from the depositing material, i.e., the self-ions, are used during deposition. Cu films were deposited on SiO_2 substrates at room temperature using 1% Cu self-ions with an energy ranging between 0--4 keV. We studied the microstructures of the Cu films using x-ray diffraction and transmission electron microscopy, measured the impurity level inside the films using secondary ion mass spectrometry, and performed the resistivity measurements using a four point probe. The results indicate that there is an optimum ion energy around 2 keV at which, the integrated x-ray intensity ratio I(111)/I(200) reaches its maximum value indicating a strong left-angle 111 right-angle texture, while the impurity concentration and resisitivity are minimum. The correlation ...
Ion bombardment during deposition can significantly modify the film properties. In the partially ionized beam deposition, ions derived from the depositing material, i.e., the self-ions, are used during deposition. Cu films were deposited on SiO{sub 2} substrates at room temperature using 1% Cu self-ions with an energy ranging between 0--4 keV. We studied the microstructures of the Cu films using x-ray diffraction and transmission electron microscopy, measured the impurity level inside the films using secondary ion mass spectrometry, and performed the resistivity measurements using a four point probe. The results indicate that there is an optimum ion energy around 2 keV at which, the integrated x-ray intensity ratio {ital I}(111)/{ital I}(200) reaches its maximum value indicating a strong {l angle}111{r angle} texture, while the impurity concentration and resisitivity are minimum. ...
Ion bombardment during deposition can significantly modify the film properties. In the partially ionized beam deposition, ions derived from the depositing material, i.e., the self-ions, are used during deposition. Cu films were deposited on SiO{sub 2} substrates at room temperature using 1% Cu self-ions with an energy ranging between 0--4 keV. We studied the microstructures of the Cu films using x-ray diffraction and transmission electron microscopy, measured the impurity level inside the films using secondary ion mass spectrometry, and performed the resistivity measurements using a four point probe. The results indicate that there is an optimum ion energy around 2 keV at which, the integrated x-ray intensity ratio {ital I}(111)/{ital I}(200) reaches its maximum value indicating a strong {l angle}111{r angle} texture, while the impurity concentration and resisitivity are minimum. ...
The effect of ionizing radiation (2, 5, and 10 KGy of gamma rays) on muscle ultrastructure of grass shrimps (Penaeus monodon Fabricius) tails at ambient or frozen (-18{sup 0}C) temperature was investigated by transmission electron microscopy (TEM). No significant change was found in muscle ultrastructure of shrimp meat irradiated at doses of 2 or 5 KGy and then stored at 4{sup 0}C for 0 and 8 days. However, in shrimps which were irradiated at ambient temperature at a dose of 10 KGy, the margin of A-band of the myofibrils in longitudinal sections exhibited an irregular zig-zag pattern. In cross section some myosin filaments in the A-band regions were missing. A possible interpretation of these results would be that 10 KGy gamma irradiation dose at ambient temperature depolymerized myosin in the A-band from the tail of thick filament. Actin damage was also observed in some cross sections. Irradiation damage of sarcoplasmic membranes appeared in ...
The effect of ionizing radiation (2, 5, and 10 KGy of gamma rays) on muscle ultrastructure of grass shrimps (Penaeus monodon Fabricius) tails at ambient or frozen (-18"0C) temperature was investigated by transmission electron microscopy (TEM). No significant change was found in muscle ultrastructure of shrimp meat irradiated at doses of 2 or 5 KGy and then stored at 4"0C for 0 and 8 days. However, in shrimps which were irradiated at ambient temperature at a dose of 10 KGy, the margin of A-band of the myofibrils in longitudinal sections exhibited an irregular zig-zag pattern. In cross section some myosin filaments in the A-band regions were missing. A possible interpretation of these results would be that 10 KGy gamma irradiation dose at ambient temperature depolymerized myosin in the A-band from the tail of thick filament. Actin damage was also observed in some cross sections. Irradiation damage of sarcoplasmic membranes appeared in the ...
Cytosine methylation in DNA is a major epigenetic signal, and plays a central role in propagating chromatin status during cell division. However the mechanistic links between DNA methylation and histone methylation are poorly understood. A multi-domain protein UHRF1 (ubiquitin-like, containing PHD and RING finger domains 1) is required for DNA CpG maintenance methylation at replication forks, and mouse UHRF1-null cells show enhanced susceptibility to DNA replication arrest and DNA damaging agents. Recent data demonstrated that the SET and RING associated (SRA) domain of UHRF1 binds hemimethylated CpG and flips 5-methylcytosine out of the DNA helix, whereas its tandom tudor domain and PHD domain bind the tail of histone H3 in a highly methylation sensitive manner. We hypothesize that UHRF1 brings the two components (histones and DNA) carrying appropriate markers (on the tails of H3 and hemimethylated CpG sites) ready to be assembled into a ...
The production of the uranium mine Zirovski Vrh ceased in 1990. The main remaining problem of the remadiation are mine and mill tailings. The uranium mine Zirovski Vrh has one mill tailings site Borst and one waste pile Jazbec. According to the Act on protection against ionising radiation and nuclear safety which was adopted by the Parliament in 2002, they are classified as radiation facilities. Slovenian Nuclear Safety Administration (SNSA) is authorised for issuing a mandatory consent to mining work. The SNSA prepared the initial proposal of content of the safety report for the mine waste pile Jazbec. In 2005, according to the detailed content of this document, the public company Zirovski Vrh Ltd prepared the safety report which was examined by an authorised expert for radiation and nuclear safety. After a careful revision of the safety evaluation report, the consensus for mining work shall be issued by the SNSA. After finishing the mining ...
TRACI, a model based on the physical mechanisms governing the radon transport in unsaturated soils, has been developed to evaluate the radon flux density at Uranium Mill Tailings (UMT) covers surface. First, moisture contents in the soil, induced by weather conditions, are calculated. Then, radon concentrations in the air-filled pore space, and radon flux density at the soil surface, are deduced from a transport model which takes account for diffusion and convection in the pore space. To check the hypothesis used in TRACI and the efficiency of cover layers, an in situ study was launched in 1997 with the French uranium mining company, COGEMA. It consists of continuous measurements of moisture contents, suctions, radon concentrations at various depths inside an UMT cover, and flux density at its surface. The first analysis made on in situ observations shows that radon concentrations and flux density, calculated with a steady-state diffusion model using monthly ...
Objective: To compare the efficiency of dual energy subtraction and conventional direct digital radiography in signal detecting ability. Methods: 200 plastic balls which were 4 mm in diameter were taken as signals and were placed on a 10 cm thick plastic board and the right upper thorax of a healthy volunteer. The signals were examined by DES and CDR separately and were estimated by 3 radiologists with 5-value-differentiation method. ROC curve analysis was made by ROC kit software. Results: when signals on plastic board were detected by CDR and DES, ROC curve analysis indicated that there was no significant difference (P=0.4851 > 0.05, two-tailed) between the area under the ROC curves of the two methods (Az=0.9931 for CDR and Az=0.9879 for DES). The difference was significant (P=0.0002 <0.01, two-tailed) between the area under the ROC curves of CDR and DES (Az=0.7276 for CDR and Az=0.8561 for DES), when the signals on the right upper ...
A biogenic method for the treatment of uranium mill effluents containing toxic amounts of Mn"2 and "2"2"6Ra is described. The acidic tailings from the uranium mills are generally neutralised with lime and the overflow waters from tailing ponds at the discharge point, consisting of Mn"2"+ (>10 mg l"-"1) and "2"2"6Ra (> 3.0 pCi l"-"1), need further treatment before disposing off to the public utility. Arthrobacter sp. has been used for precipitating Mn"2"+ as hydrous oxide of manganes (MnO_2#centre dot#nH_2O) and along with "2"2"6Ra also gets precipitated. The effluent after bacterial treatment consisted of Mn"2"+ and "2"2"6Ra within the range of allowed concentrations as per the I.C.R.P. (International Committee of Radiological Protection) and MPC (maximum permissible concentration) standards (Mn"2"+ 95% of "2"2"6Ra could be precipitated using this method. (author). 11 refs.; 4 figs.; 4 tabs.
The Belgian Malinois dog was introduced into the Department of Defense Military Working Dog Program in 1984. All dogs are purchased in Europe and have adapted well to the rigorous training requirements of the program. Most veterinary problems seen in this breed are related to kennel confinement and include traumatic dental disease, tail lesions, a variety of dermatologic conditions, and an inability to gain weight. Epilepsy is a breed problem and has been seen in this population, as has gastric dilatation/volvulus. Both elbow and hip dysplasia exist in the Malinois breed. PMID:1900116
Two new surfactant molecules are reported which contain thermally labile Diels-Alder adducts connecting the polar and non-polar sections of each molecule. The two surfactants possess identical non-polar dodecyl tail segments but exhibit different polar headgroups. The surfactants become soluble in water when anionic salts are formed through the deprotonation of the surfactant headgroups by the addition of potassium hydroxide. When either surfactant is exposed to temperature above about 60.degree. C., the retro Diels-Alder reaction occurs, yielding hydrophilic and hydrophobic fragments or the aqueous solutions of the surfactants subsequently exhibit loss of all surface-active behavior.
Two new surfactant molecules are reported which contain thermally labile Diels-Alder adducts connecting the polar and non-polar sections of each molecule. The two surfactants possess identical non-polar dodecyl tail segments but exhibit different polar headgroups. The surfactants become soluble in water when anionic salts are formed through the deprotonation of the surfactant headgroups by the addition of potassium hydroxide. When either surfactant is exposed to temperature above about 60.degree. C., the retro Diels-Alder reaction occurs, yielding hydrophilic and hydrophobic fragments or the aqueous solutions of the surfactants subsequently exhibit loss of all surface-active behavior.
Two new surfactant molecules are reported which contain thermally labile Diels-Alder adducts connecting the polar and non-polar sections of each molecule. The two surfactants possess identical non-polar dodecyl tail segments but exhibit different polar headgroups. The surfactants become soluble in water when anionic salts are formed through the deprotonation of the surfactant headgroups by the addition of potassium hydroxide. When either surfactant is exposed to temperature above about 60.degree. C., the retro Diels-Alder reaction occurs, yielding hydrophilic and hydrophobic fragments and the aqueous solutions of the surfactants subsequently exhibit loss of all surface-active behavior.
The penetration depth and concentration distribution for vanadium ions with low energy implanted into the dry peanut seeds is determined by scanning electron microscope and X-ray energy dispersion spectrometer. The results show that the depth-concentration distribution is a Gaussian distribution with a long tail and the maximum penetration depth is about 13.6 #mu#m for V"+ with 200 keV in cotyledon of the peanut. The experimental result of the implanted V"+ range in the peanut seeds is compared with the calculating value of the TRIM95
The DOE`s clean-up of its nuclear complex require the development of innovative technologies to convert soils contaminated by hazardous and/or radioactive wastes to forms which can be readily disposed in accordance with current waste disposal methods. The unique features of Votec CMS technology should make it particularly cost-effective process for the vitrification of soils, sediments, sludges, and mill tailings containing organic metallic and/or radioactive contaminants. This article describes the technology (Votec`s combustion and melting system), the results of testing, the demonstration plant system, and summarizes the future schedule and the equipment needed. 3 figs., 3 tabs.
The prospect for the recovery of rare earths from red mud, the bauxite tailings from the production of alumina is examined. The Jamaican red mud by far has the higher trace concentrations of lanthanum, cerium, neodymium, and yttrium. Scandium is also present. The dissolution of the rare earth is a major extraction problem because of the large volume of other materials. The recovery processes that have been proposed include the production of co-products such as iron, alumina, and titanium concentrates, with the rare earths going with the titanium. In this paper a critical examination of the possible processes are presented with the recommended research projects to be carried out.
Some bacteria move inside cells by recruiting the actin filaments of the host cells. The filaments are polymerized at the back surface of the bacteria, and they move away, forming a "comet" tail behind the bacterium, which consists of gel network. We develop a one-dimensional mathematical model of the gel based on partial differential equations which involve the number of filaments, the density and velocity of the gel, and the pressure. The two end-points of the gel form two free boundaries. The resulting free boundary problem is rather non-standard. We prove local existence and uniqueness.
The mine dumps that arise from the gold mining operations in South Africa are a potential source of high concentrations of radon (222"Rn). Studying the diffusion of radon and the emanation from the soil will help to deduce the radon flux from these dumps to identify the problem areas for rehabilitation. This study describes measurements of the emanation coefficient and the modelling of the depth profile of the radon activity concentration, which is compared to a depth profile that was measured on such a mine dump. Emanation coefficients ranging from 0.13 to 0.39 have been obtained.
A few industry-derived and conventional building materials have above acceptable radioactivity. An examination of some materials presently used, or with a potential for use, has shown that in phosphogypsum, fly ash, zircon kyanite tailings, red mud and brickmaking clay, the radium equivalent activities of the finer fractions (<53 #mu#) are higher than those of the larger fractions. Consequently, the radioactivity of these materials could be reduced by dry-sieving and discarding the fines. In blast furnace slag and dissociated zircon, no such reduction would occur since the radioactivity is evenly distributed in all sized fractions.
The review covers the development within the field of cleavable surfactants since 2003. Cleavable surfactants are amphiphiles in which a weak linkage has been deliberately inserted, normally, but not always, between the hydrophobic tail and the polar headgroup. Alkali labile linkages that have been used for the purpose include normal ester bonds, betaine esters, and carbonates. Ketals and ortho esters are example of bonds that are susceptible to acid hydrolysis. Several investigations deal with cationic ester-containing surfactants, both monomeric and dimeric species, the latter being gemini surfactants. Ester, amide and carbonate containing surfactants have been investigated with respect to enzyme catalyzed hydrolysis. The main incentive for the development of novel cleavable surfactants ...
Cathodic arc deposition is an established and industrially applied technique for the formation of nitrides (e.g. TiN); it can also be used for metal oxide thin film formation. A cathodic arc plasma source with the desired cathode material is operated in an oxygen atmosphere of appropriate pressure, and metal oxides of various stoichiometric composition can be formed on different substrates. We report here on a series of experiments on metal oxide formation by cathodic arc deposition for different applications. Black copper oxide has been deposited on accelerator components to increase the radiative heat transfer between the parts. Various metal oxides such as tungsten oxide, niobium oxide, nickel oxide and vanadium oxide have been deposited on ITO glass to form electrochromic films for window applications. Optical waveguide structures can be formed by refractive index variation using oxide multilayers. ...
The dry deposition of pollutants can be calculated from the concentration of pollutants in the atmosphere and deposition velocity. To calculate deposition velocity, turbulence parameters such as friction velocity and Monin-Obukhov length are used. However, due to the difficulties in observation of turbulence parameters, usually mean values of wind speed and temperature observed using conventional meteorological instruments are used to estimate the dry deposition. The dry deposition velocity is the function of aerodynamic resistance (R{sub a}), sublayer resistance (R{sub b}), surface resistance (R{sub c}). R{sub a} and R{sub b} are calculated from turbulence parameters and R{sub c} is related to surface characteristics. The purpose of the present study is to compare the dry deposition obtained using the data sets of mean values and turbulence parameters measured ...
The radiation decimal reduction dose (D_1_0) of toxigenic Vibrio cholerae O1 El Tor, Inaba was determined in vitro (0.13 kGy) and in inoculated fresh fillets of saurel (Trachurus picturatus murphyi) (0.12 kGy) and another Pacific fish species known in Peru as ''lisa'', Mugil cephalus (0.13 kGy), both of which are frequently consumed raw in ''ceviche''. The D_1_0 value was similarly determined in tails of the shrimp species Penaeus vannamei (0.13 kGy). In a second phase of the study, radiation doses in the range 1.0-4.0 kGy were evaluated for use in microbiological shelf-life extension of the selected seafood, and for adverse effects on various sensory attributes (appearance, odor, flavor, and texture). A dose of 1.0 kGy doubled the microbiological shelf-life of fish fillets during post-irradiation storage at 0-1 deg. C to approximately 30 days. This dose was deemed optimal also for preserving all sensory characteristics evaluated except appearance, due to a ...
Synthetic atrial natriuretic peptide (carperitide) and B-type natriuretic peptide (BNP; nesiritide) are used to treat congestive heart failure. However, despite beneficial cardiac unloading properties, reductions in renal perfusion pressures limit their clinical effectiveness. Recently, CD-NP, a chimeric peptide composed of C-type natriuretic peptide (CNP) fused to the C-terminal tail of Dendroaspis natriuretic peptide (DNP), was shown to be more glomerular filtration rate-enhancing than BNP in dogs. However, the molecular basis for the increased responsiveness was not determined. Here, we show that the DNP tail has a striking effect on CNP, converting it from a non-agonist to a partial agonist of natriuretic peptide receptor (NPR)-A while maintaining the ability to activate NPR-B. This effect is specific for human receptors because CD-NP was only a slightly better activator of rat NPR-A due to the promiscuous nature of CNP in this species. ...
In vertebrates, the positioning of the internal organs relative to the midline is asymmetric and evolutionarily conserved. A number of molecules have been shown to play critical roles in left-right patterning. Using representational difference analysis to identify genes that are differentially expressed on the left and right sides of the chick embryo, we cloned chick Claudin-1, an integral component of epithelial tight junctions. Here, we demonstrate that retroviral overexpression of Claudin-1, but not Claudin-3, on the right side of the chick embryo between HH stages 4 and 7 randomizes the direction of heart looping. This effect was not observed when Claudin-1 was overexpressed on the left side of the embryo. A small, but reproducible, induction of Nodal expression in the perinodal region on the right side of the embryo was noted in embryos that were injected with Claudin-1 retroviral particles on their right sides. However, no changes in Lefty,Pitx2 or cSnR expression were observed. ...
Sputter-deposited tantalum (Ta) and reactively sputter-deposited Ta-nitride films were studied with respect to the passivation capability against copper (Cu) oxidation in thermal O{sub 2} ambient. A 200 {angstrom} Ta or Ta-nitride film was sputter-deposited on a 2,000 {angstrom} Cu film using a Ta target in an Ar/N{sub 2} gas mixture. With Ta passivation, Cu was not oxidized at temperatures up to 400 C, which can be further improved by using passivation of an amorphous Ta-nitride film deposited in an appropriate condition. The absence of long-range defects in the Ta-nitride film was presumably responsible for this improvement. However, sputtering-induced surface damage by excess N{sub 2} in the sputter gas mixture may reduce the passivation capability of Ta-nitride films. When the passivated Cu was oxidized, the Cu oxides always resided in the top surface region. That is, in the oxidation process, Cu ...
A "hemispheres-in-cell" geometry is provided for prediction of colloid retention during transport in porous media. This new geometry preserves the utilities provided in the Happel sphere-in-cell geometry; namely, the ability to predict deposition for a range of porosities, and representation of the influence of neighboring collectors on the fluid flow field. The new geometry, which includes grain to grain contact, is justified by the eventual goal of predicting colloid deposition in the presence of energy barriers, which has been shown in previous literature to involve deposition within grain to grain contacts for colloid:collector ratios greater than approximately 0.005. In order to serve as a platform for predicting deposition in the presence of energy barriers, the model must be shown capable of quantitatively predicting deposition in the absence of energy barriers, which is a ...
A thin film microoxidation test utilizing the concept of the Lubricant Stability Map has been used to study the effect of temperature on deposit formation by lubricants on upper piston locations of low heat rejection engines. The stability maps were established for two formulated lubricants in this study. These two lubricants were also evaluated in a series of engine tests with various piston temperatures. The deposition phenomena observed in the engine tests have been adequately simulated and described by the stability maps. It is concluded that lubricants at upper piston locations are under a thin film condition similar to that achieved by the thin film microoxidation test. The deposit formation trend is determined by the volatility, thermal stability, and oxidative stability of the base stock. Additives have little effect on deposit formation at very high temperatures. A combined consideration of all ...
The localized Pt deposition on Si by 30 keV Ga"+ focused ion beam (FIB), 10 keV electron beam (EB) or dual beams (FIB and EB) using precursor gas has been compared by analysis using a 300 keV Be"2"+ microprobe with a beam spot size of 80 nm. The distribution of deposited Pt, Ga from the ion beam itself, and C from the precursor gas was obtained at and nearby the deposited areas by micro-RBS spectra and RBS mapping. All of the beam processed areas showed a uniform Pt distribution at the deposited areas. The amount of Pt atoms increased with the increase in ion or electron dose due to the decomposition of precursor gas. The thickness of Pt layer by EB is considerably less than that by FIB due to the reduced deposition rate. Ga atoms from the center of processed areas partly redeposited at and nearby the FIB processed areas within #approx#3 #mu#m. The Ga incorporation by dual beam ...
Applying the theory of depositional system, the depositional facies and depositional systems of the Zhiluo Formation in Dongsheng area are systematically analysed, and the authors proposed that sediments of the Zhiluo Formation are of fluvial facies, and streams of the Zhiluo time experienced three evolution stages, namely: the early braided stream, the middle low sinuosity meandering stream and the late high sinuosity meandering stream. Based on features of paleoclimatic evolution, the Zhiluo Formation is divided into two lithological members. The lower lithological member consists of sediments of braided and low sinuosity meandering streams under humid-ward paleoclimatic conditions forming grey sedimentary formation. The upper member is composed of sediments of meandering streams under arid-hot paleoclimatic conditions representing complex-colored (mainly red) sedimentary formation. It is suggested that uranium ...
This report describes modelling where the hydrological modelling system MIKE SHE has been used to describe surface hydrology, near-surface hydrogeology, advective transport mechanisms, and the contact between groundwater and surface water within the SKB site investigation area at Laxemar. In the MIKE SHE system, surface water flow is described with the one-dimensional modelling tool MIKE 11, which is fully and dynamically integrated with the groundwater flow module in MIKE SHE. In early 2008, a supplementary data set will be available and a process of updating, rebuilding and calibrating the MIKE SHE model based on this data set will start. Before the calibration on the new data begins, it is important to gather as much knowledge as possible on calibration methods, and to identify critical calibration parameters and areas within the model that require special attention. In this project, the MIKE SHE model has been further developed. The model area has been extended, and the present ...
Evidence for the presence of undecaprenol in the unsaponifiable lipid of Lactobacillus plantarum (N.C.I.B. 6376) is presented. Characterization of the compound was based mainly on...Full Text Available
Robert A. Martock. Cleveland State University, Cleveland, Ohio. Synthesis and Structural Characterization of a. Novel Indium Mercapto Derivative. [Clln(SCH. 2 ...
Recent molecular characterizations of Cryptosporidium parasites make it possible to differentiate the human-pathogenic Cryptosporidium parasites from those that do...Full Text Available
This paper describes attempts to isolate and characterize glycosaminoglycan (GAG)-binding molecules on the surface of lymphocytes and lymphoma cell lines and relate their expression to splenic and lymph...Full Text Available
BackgroundA mycovirus previously identified in brown discolored fruiting bodies of the cultivated mushroom Flammulina velutipes was characterized. We tentatively...Full Text Available
Axial offset anomaly (AOA) is caused by the deposition of crud on the fuel cladding of a PWR. When significant levels of crud build up on the cladding, boron can accumulate in the pores of the crud as a concentrated solution or solid phase, and cause the flux depression. Numerous studies have been conducted on the primary water chemistry to reduce the amount of crud in the primary circuit to avoid radioactivity buildup and unexpected power transition in the plant. However, experiments on the crud are restricted in the laboratory because the crud is a highly radioactive material. The objective of this study is to develop a test method for simulating the deposition of crud in a nuclear power plant
High power and particle deposition on target materials are encountered in many applications including magnetic and inertial fusion devices, nuclear and high energy physics applications, and laser and discharge produced plasma devices. Surface and structural damage to plasma-facing components due to the frequent loss of plasma confinement remains a serious problem for the Tokamak reactor concept. The deposited plasma energy causes significant surface erosion, possible structural failure, and frequent plasma contamination.
Energy conservation and local energy deposition are investigated in the context of coupled-particle (i.e., neutrons, gamma rays, and charged particles) transport analysis. For charged particles, the concept of group splitting the 1 = 0 transfer matrix to ensure both particle and energy conservation is introduced. Although these procedures are more complex than those found in the usual neutron or coupled-neutron gamma-ray problem, they yield a consistent approach for the calculation of local energy deposition.
Energy conservation and local energy deposition are investigated in the context of coupled-particle (i.e., neutrons, gamma rays, and charged particles) transport analysis. For charged particles, the concept of group splitting the 1 = 0 transfer matrix to ensure both particle and energy conservation is introduced. Although these procedures are more complex than those found in the usual neutron or coupled-neutron gamma-ray problem, they yield a consistent approach for the calculation of local energy deposition.
The addition of carbon to samples, during imaging, presents a barrier to accurate TEM analysis, the controlled deposition of hydrocarbons by a focused electron beam can be a useful technique for local nanometer-scale sculpting of material. Here we use hydrocarbon deposition to form nanopores from larger focused ion beam (FIB) holes in silicon nitride membranes. Using this method, we close 100-200nm diameter holes to diameters of 10nm and below, with deposition rates of 0.6nm per minute. I-V characteristics of electrolytic flow through these nanopores agree quantitatively with a one dimensional model at all examined salt concentrations.
In this study, liquid flame spray (LFS) was used to produce titania, silver and silver-titania deposits of nanoparticles. Titanium(IV)ethoxide (TEOT) and silver nitrate in ethanol solutions were used as precursors and sprayed into turbulent hydrogen-oxygen flame. Production rates of 1.5-40 mg/min of titania were used with silver additions of 1, 2, 4, and 8 wt% compared to titania. Nanoparticle deposits were collected by thermophoretic sampling at six different axial distances from the flame torch head: 3, 5, 10, 12, 15, and 20 cm, of which the all but the last one occurred inside the flame. The deposit samples were analysed by TEM and SAED analysis. The powder samples of the particles were also collected by electric precipitator to XPS and specific surface area analysis. Particle size and effective density after the flame in the aerosol were analysed with SMPS and ELPI. The results from the previous studies i.e. controlling ...
There is increasing demand to functionalize meso- and nano-porous materials by coating and make the porous substrate biocompatible or environment friendly. However, coating on a meso-porous substrate poses great challenges, especially if the pore aspect ratio is high. In the current work the pulsed laser deposition (PLD) method is used for coating Ni{sub 3}Al-based meso-porous membranes with diamond-like carbon (DLC) layers of high thickness homogeneity and adhesion. (orig.)
One of the NASA research activities was to identify, characterize, and simulate a series of technologies that could be used for hydrogen production at NASA Kennedy Space Center (KSC) using locally available sources. This project examined the production of hydrogen from solar energy. To produce hydrogen by water splitting, the operating voltage of conventional photovoltaic (PV) cells cannot supply the overvoltage required. Thus, the objective of this project was to research and develop photoelectrochemical (PEC) cells that can supply the required voltage for water splitting by constructing a multiple bandgap tandem PV cell and a photocatalyst that can be activated by infrared (IR) photons transmitted through the PV cell. The proposed concept is different from conventional PEC water splitting by using multiple band gap combinations. The advantages for this PEC cell concept is that the PV cells are not in contact with the electrolyte solution, thus reducing the ...
The partial oxidation of 1,3-butadiene has been investigated over VMoO catalysts synthesized by sol-gel techniques. Surface areas were 9-14 m{sup 2}/g, and compositions were within the solid solution regime, i.e. below 15.0 mol % MoO{sub 3}/(MoO{sub 3} + V{sub 2}O{sub 5}). Laser Raman Spectroscopy and XRD data indicated that solid solutions were formed, and pre- and post-reaction XPS data indicated that catalyst surfaces contained some V{sup +4} and were further reduced in 1,3-butadiene oxidation. A reaction pathway for 1,3-butadiene partial oxidation to maleic anhydride was shown to involve intermediates such as 3,4-epoxy-1-butene, crotonaldehyde, furan, and 2-butene-1,4-dial. The addition of water to the reaction stream substantially increased catalyst activity and improved selectivity to crotonaldehyde and furan at specific reaction temperatures. At higher water addition concentrations, furan selectivity increased from 12% to over 25%. The catalytic effects of water addition were ...
Throughout the last decades, plasma technology has been established in a series of surface treatment applications, e.g. for semiconductor processing or optical coatings. The majority of plasma assisted technologies is based on low pressure processes. In recent years, however, non-thermal atmospheric pressure discharges have attracted considerable interest because of their simplified technical devices for industrial applications as compared to low pressure processes which require vacuum equipment. Hence, batch processing can be avoided, thus facilitating the implementation of plasma process steps into production lines. Investment costs are cut down significantly. The use of atmospheric pressure plasmas for technical applications dates back to the ozone production with dielectric barrier discharges (DBD) by Siemens in 1857. Lately, the application of atmospheric pressure plasmas for surface treatment has been reported, e.g. for the treatment of foils to improve printability, for surface ...
Current methods to calculate dose distributions with organ motion can be broadly classified as 'dose convolution' and 'fluence convolution' methods. In the former, a static dose distribution is convolved with the probability distribution function (PDF) that characterizes the motion. However, artifacts are produced near the surface and around inhomogeneities because the method assumes shift invariance. Fluence convolution avoids these artifacts by convolving the PDF with the incident fluence instead of the patient dose. In this paper we present an alternative method that improves the accuracy, generality as well as the speed of dose calculation with organ motion. The algorithm starts by sampling an isocenter point from a parametrically defined space curve corresponding to the patient-specific motion trajectory. Then a photon is sampled in the linac head and propagated through the three-dimensional (3-D) collimator structure corresponding to a particular MLC segment ...
ABSTRACT Shallow-lacustrine delta deposits of the Upper Triassic Yanchang Formation form the most important petroleum reservoir sandstone units in the Ordos Basin, China. Recent hydrocarbon exploration and outcrop studies demonstrated that shallow-lacustrine sand-rich deltas developed extensively along the gentle flanks and central part of the basin. The vertical succession of facies indicates that the Yanchang Formation records the entire lacustrine life cycle of the Late Triassic Ordos Basin. Four third-order transgressive-regressive cycles and two larger shallow-lacustrine deltaic cycles have been recognized. A process-based depositional model, derived in part from the modern Ganjiang delta in Poyang Lake, China, is used to infer the origins of the sand-rich lacustrine delta deposits. S...
The workshop topics consist of FERS, FEGLI, FEHBP, Disability, Deposit/Redeposit ; TSP, Annual/Sick Leave, Annuity Calculation, Best Date to Retire, COLA's, ...
The goal of this research program is to determine whether pulsed laser deposition is an effective alternative method for growing TiCN thin films. Pulsed laser deposition (PLD) is chosen because of its well-documented capability for growing uniform, stoichiometric films in ultra-high vacuum or gaseous environments. Processing of thin films by PLD is also achieved at relatively low temperatures compared with CVD processing. Given these attributes, the primary objectives in this article are to determine whether nitrogen may be readily incorporated into films resulting from the laser-ablation of TiC in an N{sub 2} environment, determine what effect nitrogen has on mechanical properties, and determine whether nitrogen incorporation is strongly influenced by processes unrelated to laser deposition (e.g., thermally-activated surface reactions).
Oil shales of the US represent a tremendous store of potential oil. Most of the deposits are relatively unknown and warrant additional investigation. The summary presented cannot hope to cover all of the deposits. Information about them is usually available only locally. However, the 3 best known deposits - the Green River formation, the Devonian black shales, and the retort member of the Phosphoria formation - represent well over 2 trillion bbl (300 x 10/sup 12/ ton) of potential oil in place. This is an oil resource large enough to supplement quite adequately the US petroleum supply, to extend the time available for realigning our energy supply mixes, and to help reach a satisfactory solution to our current energy dilemma. The concentrated resource in the Green River formation is obviously the next most feasible source of oil. If it cannot be developed, all the other deposits will have to wait until ...
... ge aircraft engines (geae) has taken to development an induction plasma deposition (ipd) processing method for the fabrication of ti6242/sic mmc ...
The distribution of Lipiodol in the liver and lungs following arterial or portal injection was studied in normal (n=55) and cirrhotic rats (n=20). Using magnified xeroradiography and radioisotope labeled tracers, it was found that Lipiodol was deposited mainly in the liver and lung after either arterial or portal administration. In control rats after arterial injection, deposits in the lung peaked after 2 hours and gradually declined over 48 hours; whereas after portal injection, the deposit steadily increased for 48 hours. Twenty-five percent of cirrhotic rats demonstrated a Lipiodol-induced miliary pattern in the lung. An increased number of portosystemic shunts in cirrhotic rats was also noted. These results suggest that cirrhosis of the liver may be a potential risk factor for developing pulmonary complications after Lipiodol administration. (orig.).
A procedure based on electrophoretic deposition (EPD) was developed to coat metal plates with powder catalysts. The method was tested on stainless-steel plates with three Ni-based catalysts for the steam reforming of ethanol. The catalysts (Ni/La2O3/g-Al2O3) contained 15% Ni and 8% La, and were prepared using three types of g-alumina with different textural properties. The powder catalysts were suspended in isopropanol, and EPD deposition was performed with a voltage of 100V and a distance between electrodes of 2cm. Deposition time was varied between 3 and 7min, which gave a thickness of the catalyst layer from around 30 to 100mm. The morphology of the catalyst layer was dependent on the textural characteristics of the g-Al2O3 used to prepare the catalyst. The activity of the catalyst plat...
Indium sulfide thin films were deposited onto indium-tin-oxide coated glass substrate by electrochemical deposition from an aqueous solution containing In2 (SO4) 3 and Na2S2O3. The deposition conditions were optimized on the basis of data obtained by scanning electron microscope, Auger electron spectroscopy and optical transmission measurements. Furthermore, the photosensitivity of the films was observed by means of photoelectrochemical measurements, which confirmed that the indium sulfide showed n-type conduction. The X-ray diffraction and Raman studies revealed that the as-grown films were amorphous or nanocrystalline in nature and became polycrystalline In2S3 after annealing.
Corrosion behavior of deposition coated specimens prepared by the technique proposed by the authors is investigated in salt immersion tests, and also those of pure magnesium, 3N, 4N and 6N grades, and magnesium alloys, AZ31 and AZ91E, are investigated for comparison. Inhomogeneous corrosion occurs in AZ31 and AZ91E alloys when buffered solutions with pH values of 6.5 and 9.0 including 1% NaCl and a conventional 3% NaCl solution are used for immersion tests, while 6N-Mg shows homogeneous corrosion in such solutions. Corrosion behavior of the deposition coated specimen resembles that of 6N-Mg. Purification process included in the deposition coating technique provides homogeneity in microstructural and electrochemical terms, which results in improving corrosion resistance. (orig.)
The corrosion behavior of the sputter-deposited amorphous or nanocrystalline W-Nb alloys is studied in 10% NaCl, 0.1 and 1 M NaOH solutions at 24 deg. C, open to air using immersion tests and electrochemical measurements. Niobium metal acts synergistically with tungsten in enhancing the corrosion resistance of the W-Nb alloys so as to show lower corrosion rates than the corrosion rates of the alloy-constituting elements in almost all examined solutions. Corrosion rates of W-Nb alloys are about more than one order of magnitude less than that of the sputter-deposited tungsten and even lower than that of sputter-deposited niobium. The stability of the anodic passive films formed on the W-Nb alloys increase with niobium content.
Dosimetry parameters such as deposition, clearance, retention, and translocation and dissolution of inhaled particles in and to different lung compartments may be important for the persistence of particles...Full Text Available
The density of corn pollen on leaves of milkweed plants inside and outside of cornfields was measured in several studies from different localities. The purpose was to obtain a representative picture...Full Text Available
This paper reports on a series of experiments performed to examine the ability of ion beam assisted thermal deposition to produce good adhesion of Au metallization on GaAs left-angle 100 right-angle substrates. A study of the influence of Ar ion-assisted thermal deposition of the Au films as well as in situ pre-sputtering of the GaAs surface with low-energy Ar ions prior to thermal deposition, shows that strong adhesion can be achieved without resorting to chemical cleaning. The substrate temperature and the relative flux of Ar ions to incident Au atoms were varied in order to correlate these parameters with film adhesion. The interfaces of films processed under these various conditions were examined by XTEM, RBS and XPS. Orientation texture was studied by x-ray diffraction (XRD).
The method is related to hydrodynamic methods for studying wells and may be used in the prospecting and mapping of gas and gas condensate deposits and formations. The method consits of drilling exploratory wells and measurement of the physical parameters of the stratum liquid. The piezometric levels are periodically determined simultaneously in all the observation wells during a change in the atmospheric pressure, and the presence of a remoteness of the gas deposit from the well is judged from the size of the increments in the piezometric levels intime. The determinations of the piezometric levels in the wells are conducted during an abrupt change in atmospheric pressure, for instance, during the replacement of a cyclone by an anticyclone or the reverse. The atmospheric pressure is measured by a barograph, while the piezometric levels are measured by high precision level meters or pressure gauges of low pressure. The method increases the ...
Effects of ions of Group IA, IIA, IIIB, and VIIB elements on the cathodic deposition of a molybdenum were investigated in a KCl-LiCl (eutectic)-MoCl/sub 3/ molten salt at 773 K (500/degree/C). The results can be summarized as follows: The addition of potassium, rubidium, cesium, and barium cations and fluorine anions to the KCl-LiCl (eutectic)-MoCl/sub 3/ molten salt is effective in depressing the cathodic deposition of the molybdenum subchloride, which hinders the smooth, flat electrodeposition of molybdenum. The addition of lithium, sodium, magnesium, calcium, strontium, and aluminum cations and bromine and iodine anions promotes the undesirable cathodic deposition of the molybdenum subchloride.
The objectives of this project are to detect and characterize fractures in a naturally fractured tight gas reservoir, using surface seismic methods, borehole imaging logs, and in-situ stress field data. Further, the project aims to evaluate the various seismic methods as to their effectiveness in characterizing the fractures, and to formulate the optimum employment of the seismic methods as regards fracture characterization.
The effect of atmospheric radioactive emissions from United Kingdom nuclear installations on acid deposition is assessed. Nitrogen oxide and ozone production resulting from and associated with discharges of airborne radioactivity, comparison with conventional emissions, and the direct effects of radioactive emissions on trees, are all discussed. (UK).
An examination is made of the structure of the North Saremboyskiy oil field and productive lower Devonian deposits of well 15. Based on detailed lithological studies, as well as investigation of filtering-capacitance properties of rocks, the complex structure of the carbonate deposits and the dominant development of complex type collectors is indicated.
Magnetron sputter deposition was used to fabricate body centered cubic (bcc) and A-15 crystal structure W thin films. Previous work demonstrated that the as-deposited crystal structure of the films was dependent on the deposition parameters and that the formation of a metastable A-15 structure was favored over the thermodynamically stable bcc phase when the films contained a few atomic percent oxygen. However, the A-15 phase was shown to irreversibly transform into the bcc phase between 500 C and 650 C and that a significant decrease in the resistivity of the metallic films was measured after the transformation. The current investigation of 150 nm thick, sputter deposited A-15 and bcc tungsten thin films on silicon wafers consisted of a series of experiments in which the stress, resistivity and crystal structure of the films was measured as a function of temperatures cycles in a Flexus 2900 thin film ...
Exploration for oil shale in Queensland between June 1986 and July 1987 continued over 12 deposits ranging in age from Permian to Tertiary. The total estimated resource of shale oil contained within these deposits is 4479 GL (28.2 billion barrels). 4 refs., 1 fig., 1 tab.
Natural radioactivity of rocks is studied on the basis of core samples and radioactivity logs of marine deposits in Azerbaijan. Investigations have established mainly thorium-potassium nature of radioactivity. Data obtained are useful for identificafion of clay among other rocks, for determination of clayiness, and in presence of a corresponding relation - for determination of porosity according to the clayiness. It is shown that the clayiness may be determined from radioactive logs.
The mobilization and distribution of previously deposited "2"3"9Pu was compared in pregnant rats (15 and 20 days of gestation) and nonpregnant controls. Pregnancy had little effect on "2"3"9Pu tissue burdens and only minimal activity appeared in the fetoplacental unit. Marked differences were observed in tracer "4"5Ca deposition patterns between the experimental groups.
The formulation of the problem of classification of lithologically heterogeneous rocks and rocks with mixed capacity space is analyzed under conditions of self-teaching. Using the example of one of the boreholes of the Pripyat trough we illustrated the possibilities of the Kompakt algorithm to classify deposits of the Frasnian stage without using standard data. Problems are listed for further study on the development of methods of application of self-teaching classification systems in the petroleum industry.
In accordance with the comprehensive plan in the eleventh five-year period the main content of prospecting and exploration on land in Axerbaidzhan by the Axneft' association will be done in the central and Western regions of the republic, where Paleogene-Mesozoic deposits will be inspected. Discussed in detail are the directions and volumes of prospecting and exploration in individual regions of Azerbaidzhan. They are determined with consideration of the degree of exploration of the earth's interior, the prospects for the deposits comprising them, and the development of the resources of oil.
Approximately 700m of deep water clastic deposits of Mt. Messenger Formation are superbly exposed along the Taranaki coast of North Island, New Zealand. Biostratigraphy indicates the interval was deposited during the time span 10.5-9.2m.y. in water depths grading upward from lower bathyal to middle-upper bathyal. This interval is considered part of a 3rd order depositional sequence deposited under conditions of fluctuating relative sea-level, concomitant with high sedimentation rates. Several 4th order depositional sequences, reflecting successive sea-level falls, are recognized within the interval. Sequence boundaries display a range of erosive morphologies from metre-wide canyons to scours several hundred metres across. All components of a generic lowstand systems tract--basin floor fan, channel-levee complex and progading complex--are present in logical and temporal order. They ...
The glacial deposits of the West Tensleep Basin in the Bighorn Mountains of Wyoming are mapped and a relative chromology established. The deposits are correlated with the regional model as defined in the Wind River Mountains. A statistical analysis is performed on the density and weathering characteristics of the surficial boulders to determine their validity as indicators of relative age. (ACR)
Deposition of CN-based films by a novel version of active screen plasma nitriding, aiming at surface modification of polymers, is reported. The approach relies on the use of pure graphite as the grid material, which was found to act both as an active screen and as a dry source of carbon atoms for the synthesis of thin films consisting mainly of a stoichiometric CN layer with columnar-type structure and dome-like nanostructured morphology.
The principal types of uranium deposits in Ontario are carbonatites and fenites, alkalic volcanic rocks, pegiatites, calc-silicate rocks, pyritic quartz-pebble conglomerates, polymictic conglomerates and some pelitic rocks, and various 'pitchblende' deposits including late Precambrian unconformities, possibly late Precambrian diabase dikes, and other unconformities: carbonates, sandstones, lignites, and semi-pelitic rocks of middle and upper Precambrian age. Only red unzoned pegmatite and the pyritic quartz-pebble conglomerate have supported production. Ontario reasonably assured and estimated resources in the economic and subeconomic categories in 1977 amounted to 553 000 tonnes U, and 1977 production was 4000 tonnes U. Measured, indicated, and inferred resources in the Elliot Lake - Agnew Lake area are at least 400 000 tonnes U. The latter deposits are also a significant thorium resource. Geological features reflecting ...
This paper examines the correlation between mechanical properties and the density, phase, and hydrogen content of deposited alumina layers, and compares them to those of sapphire and amorphous alumina synthesized through ion-beam irradiation of sapphire. Alumina films were deposited using electron beam evaporation of aluminum and co-bombardment with O{sub 2}{sup +} ions (30-230 eV) from an electron cyclotron resonance (ECR) plasma. The H content and phase were controlled by varying the deposition temperature and the ion energy. Sapphire was amorphized at 84 K by irradiation with Al and O ions (in stoichiometric ratio) to a defect level of 4 dpa in order to form an amorphous layer 370 nm thick. Nanoindentation was performed to determine the elastic modulus, yield strength and hardness of all materials. Sapphire and amorphized sapphire have a higher density and exhibit superior mechanical properties in comparison to the ...
Abstract A next generation material for surface passivation of crystalline Si is Al2O3. It has been shown that both thermal and plasma-assisted (PA) atomic layer deposition (ALD) Al2O3 provide an adequate level of surface passivation for both p- and n-type Si substrates. However, conventional time-resolved ALD is limited by its low deposition rate. Therefore, an experimental high-deposition-rate prototype ALD reactor based on the spatially separated ALD principle has been developed and Al2O3 deposition rates up to 1.2-nm/s have been demonstrated. In this work, the passivation quality and uniformity of the experimental spatially separated ALD Al2O3 films are evaluated and compared to conventional temporal ALD Al2O3, by use of quasi-steady-state photo-conductance (QSSPC) and carrier density ...
Highly conductive biaxially textured RuO_2 thin films were deposited on technically important SiO_2/Si substrates by pulsed laser deposition, where yttria-stabilized zirconia (YSZ) produced by ion-beam-assisted-deposition (IBAD) was used as a template to enhance the biaxial texture of RuO_2 on SiO_2/Si. The biaxially oriented RuO_2 had a room-temperature resistivity of 37 #mu##OMEGA#-cm and residual resistivity ratio above 2. We then deposited Ba_0_._5Sr_0_._5TiO_3 thin films on RuO_2/IBAD-YSZ/SiO_2/Si. The Ba_0_._5Sr_0_._5TiO_3 had a pure (111) orientation normal to the substrate surface and a dielectric constant above 360 at 100 kHz. copyright 1998 Materials Research Society.
During last decade, considerable interest has been focused to assess the influence of human activities on ecosystems. The increasing trend in the atmospheric concentration of CO{sub 2} has been predicted to continue till the next century and the amount of nitrogen deposition in the northern hemisphere has increased markedly. Substantial interest has been focused on predicting how these changes will affect on plants. Most boreal mire ecosystems are dominated by mosses of the genus Sphagnum, the litter of which constitutes the main component in the peat deposits and is an important CO{sub 2} sink via peat formation. Since virtually nothing was known about the growth response of peat mosses to elevated concentrations of CO{sub 2} and alerting changes in species composition were detected in the sensitive ombrotrophic mire vegetation under increased N deposition in central Europe, this study was established. Laboratory ...
The Grand Canyon Quadrangle (2/sup 0/), northwestern Arizona, was evaluated to identify environments and delineate areas favorable for the occurrence of uranium deposits. This was done using criteria developed for the National Uranium Resource Evaluation. General surface reconnaissance and geochemical sampling were carried out in all geologic environments within the quadrangle. Aerial radiometric and hydrochemical and stream-sediment reconnaissance surveys were performed, although results were not available in time for field checking. The results of this investigation indicate environments favorable for: channel-controlled, peneconcordant sandstone deposits in the Petrified Forest Member of the Chinle Formation in the north-central part of the quadrangle, vein-type deposits in collapse breccias in all areas underlain by the Redwall Limestone, and unconformity-related deposits in the metasediments of the ...
An in-plane uniaxial magnetic anisotropy has been observed in thin Co films normally deposited onto obliquely sputtered Ta and Pt underlayers. Associated with this anisotropy is an augmented easy axis coercivity. The in-plane easy axis is, in most cases, perpendicular to the incident deposition plane. Microstructural results indicate that grains are well connected along the magnetic easy axis but are separated by long continuous voids along the hard axis, which is ascribed to a geometric shadowing effect due to the oblique incidence deposition of the underlayer. Hence, the magnetic anisotropy mimics the film growth anisotropy. It is therefore believed that the observed magnetic properties are due to magnetostatic shape anisotropy effects. In-plane coercivity and anisotropy field are shown to increase with underlayer deposition angle, underlayer thickness and magnetic layer thickness. The choice of ...
The Sunoco Felda oil trend of the South Florida basin has been a prolific oil producer. All the oil is produced from the Cretaceous Sunniland formation, a leached limestone bioherm. Although the producing section has been considered reefal in the literature, petrographic and biostratigraphic analyses of various cores in producing fields have determined that these deposits are composed of particles of fragmented rudist and other fauna deposited in a tidal shoal. Atop this debris an algae and gastropod section has been deposited, typical of a mound deposited on a tidal mud flat. This model is exemplified in the Sunoco Felda and West Sunoco fields and was used in exploring the Sunoco Felda trend. From the petrological analysis of these two fields and from knowledge of other wells in the basin, biostratigraphic and lithologic trends can be determined and extended offshore into the eastern Gulf of Mexico. ...
The objective of this project were to investigate the dynamic behavior of peat and to evaluate the influence of that behavior on the dynamic response of peat deposits. During the course of the research, the objectives were expanded to explore the effects of strong earthquake shaking on pile foundations embedded in peat deposits. An experimental investigation was undertaken using samples of a peat deposit typical of many large peat deposits in western Washington. A series of ground response analyses was performed to investigate the seismic response of peat deposits. Three vertical profiles through Mercer Slough were analyzed using both equivalent linear and nonlinear ground response analyses. The analyses showed that the soft nature of the Mercer Slough peat would produce amplification of the long-period components of an earthquake ground motion. Comparison of the equivalent linear ...
High-resolution sequence stratigraphy taking base-level cycles as interface of reference was developed rapidly in recent years. Its greatest predominance lies in that it can be applied to multi-controled continental sedimentary basins and can effectively improve accuracy and distinguishability of sequence stratigraphy analysis. Principles of base-level cycles can also be applied to the research and practice of the exploration and exploitation of sandstone-type uranium deposits as they control the spatial distribution, porosity, the permeability and the sealing ability of sandstone and mudstone, and stacking patterns of strata configuration. Taking Dongsheng uranium deposits as an example, the application of base-level cycles to exploration and exploitation of sandstone uranium deposits was analyzed. It is suggested that favorable strata framework of sandstone and mudstone was developed very well in the fluctuation of ...
Deposition of hard coatings may influence the mechanical properties of the bulk material and its corrosion resistance. In this work we study the hardness of the coated and the back side of 100Cr6 steel plates. Electrochemical corrosion tests were performed in O{sub 2}-saturated acetate buffer of pH 5.6 at 25degC. Chromium nitride and titanium nitride coatings prepared by different physical vapour deposition processes, such as arc, thermionic arc evaporation, magnetron sputtering and ion-beam-assisted deposition (IBAD) were compared. The results show that, for sufficient corrosion protection, chromium nitride layers have to be thicker than 500 nm. An increased nitrogen partial pressure in the evaporation chamber of the IBAD process improves the corrosion resistance significantly. The hardness of the substrates was reduced in the case of thermoionic arc evaporation only, indicating a deposition ...
We demonstrate the use of a variational method to determine a quantitative lower bound on the rate of convergence of Markov Chain Monte Carlo (MCMC) algorithms as a function of the target density and proposal density. The bound relies on approximating the second largest eigenvalue in the spectrum of the MCMC operator using a variational principle and the approach is applicable to problems with continuous state spaces. We apply the method to one dimensional examples with Gaussian and quartic target densities, and we contrast the performance of the basic Metropolis-Hastings algorithms with a ``smart'' variant that incorporates gradient information into the trial moves. We find that the variational method agrees quite closely with numerical simulations. We also see that the smart MCMC algorithm often fails to converge geometrically in the tails of the target density except in the simplest case we examine, and even then care must be taken to choose the appropriate ...
On the 15th of June 2006 the PAMELA experiment, mounted on the Resurs DK1 satellite, was launched from the Baikonur cosmodrome and it has been collecting data since July 2006. PAMELA is a satellite-borne apparatus designed to study charged particles in the cosmic radiation, to investigate the nature of dark matter, measuring the cosmic-ray antiproton and positron spectra over the largest energy range ever achieved, and to search for antinuclei with unprecedented sensitivity. The apparatus comprises a time-of-flight system, a silicon-microstrip magnetic spectrometer, a silicon-tungsten electromagnetic calorimeter, an anticoincidence system, a shower tail catcher scintillator and a neutron detector. The combination of these devices allows charged particle identification over a wide energy range.
Numbers of wintering sea ducks, including buffleheads (Bucephala albeola; BUFF), common goldeneyes (Bucephala clangula; COGO), and long-tailed ducks (Clangula hyemalis; LTDU), increased substantially at Lake Ontario after Dreissenid mussels (Dreissena bugensis and D. polymorpha) colonized the Great Lakes. Invertebrates, including Dreissenid mussels, are major diving duck prey items that can transfer some trace elements, such as selenium (Se) to higher trophic levels. Se can be problematic for waterfowl and it often has been detected at elevated levels in organisms using the Great Lakes. There are, however, few data on hepatic Se concentrations in sea ducks, particularly during the winter at Lake Ontario. In this study, we evaluated interspecific differences and temporal trends in hepatic S...
The Canada Centre for Mineral and Energy Technology (CANMET) is a research organization dedicated to the advancement of the Canadian mining industry. It specializes in the development of new technologies and the coordination of scientific partnerships in the fields of mines, metallurgical processes, and the environment. CANMET supports a number of research and development activities related to the mining industry. In this poster presentation, the author described the mandate of CANMET by first introducing the organization chart with a special emphasis placed on the Mining and Mineral Sciences Laboratories. A description of the different types of partnerships was included, followed by specific details concerning all the projects related to the mining industry, such as terrain control, automation of mines, underground mining environment, processes and services, analytical support, environmental programs, mine effluent, waste rock and tailings, and metals and the ...
The profile of focused boron ion beam (FIB) from a liquid metal ion source was determined by MOS device characteristics and resist exposure experiments. A focused boron ion beam was line-scanned into the middle of the channel region along the source to drain direction of a MOSFET, and the effective channel width is determined from electrical measurements. PMMA resist was also exposed by a line-scanned boron FIB and the developed contour was observed by a SEM. The profile of the focused boron ion beam with a diameter of around 0.2 ..mu..m was determined by these two methods and it was found to have about a 1 ..mu..m wide tail at around three orders of magnitude below the peak current density region. The profile difference between the two measurements are attributed to the boron diffusion in silicon by subsequent heat-treatments during device fabrication.
Early failure of an induction-hardening carbon steel pipe, which was used to transport tailing slurry, was caused by pitting corrosion. The microstructure on the internal pipe surface layer was found being a mixture of martensite, pearlite and ferrite. In this work, the pitting corrosion behavior of each constitute in the microstructure of steel is investigated with electrochemical noise analyses; the electronic properties of passive films were studied with Mott-Schottky relationship. It is found that the passive films formed on the materials under investigation are highly disordered n-type semiconductors. The high-to-low pitting susceptibility is ferrite > martensite > pearlite. The pitting resistance is related to the semiconductive nature of the passive film formed on each constitute. The pitting susceptibility increases with the donor concentration in the passive films. (author)
The petroleum ether fraction (PEF) from the EtOH extract of flowers and buds of Chrysanthemum indicum was evaluated on antinociception in mice using chemical and thermal models of nociception. PEF administered orally at doses of 188 and 376mg/kg produced significant inhibitions on chemical nociception induced by intraperitoneal acetic acid, subplantar formalin or capsaicin injections and on thermal nociception in the tail-flick test and the hot plate test. In the pentobarbital sodium-induced sleep time test and the open-field test, PEF neither enhanced the pentobarbital sodium-induced sleep time nor impaired the motor performance, indicating that the observed antinociception was unrelated to sedation or motor abnormality. In a measurement of core body temperature, PEF did not affect temper...
Radiolabeled lipiodol has been used for targeting liver cancer. We developed a lipiodol solution of {sup 188}Re-TDD (2,2,9,9-tetramethyl-4,7-diaza-1,10-decanedithiol) and investigated its feasibility for the treatment of liver cancer. The lipiodol solution of {sup 188}Re-TDD was well-retained in the lipiodol phase in vitro. After injection through the tail veins of mice, high lung-uptake was investigated which is evidence of embolizing activity. We also found high accumulation in hepatoma after injection through the hepatic arteries of hepatoma-bearing rats. In conclusion, the lipiodol solution of {sup 188}Re-TDD is a promising agent for liver cancer therapy.
The authors have cloned a full-length putative rat pancreatic lysophospholipase cDNA by an improved mRNA isolation method and cDNA cloning strategy using (/sup 32/P)-labelled nucleotides. These new methods allow the construction of a cDNA library from the adult rat pancreas in which the majority of recombinant clones contained complete sequences for the corresponding mRNAs. A previously recognized but unidentified long and relatively rare cDNA clone containing the entire sequence from the cap site at the 5' end to the poly(A) tail at the 3' end of the mRNA was isolated by single-step screening of the library. The size, amino acid composition, and the activity of the protein expressed in heterologous cells strongly suggest this mRNA codes for lysophospholipase.
Charge transport in disordered organic semiconductors is generally described as thermally activated hopping in a gaussian distribution of localized states. The presence of charge traps is critical to the performance of organic electronic devices, since trapped charge carriers do no longer contribute to the current flow. The trap distribution in the polymer poly(3-hexylthiophene) (P3HT) is investigated by applying the fractional thermally stimulated current technique. Thereby, a low temperatur double-peak distribution has been revealed. One of the peaks is believed to belong to the tail of the intrinsic density of states, whereas the other trap is strongly affected by exposure to oxygen. We discuss the influence of oxygen exposure time on the trap distribution.
The risks from mining and processing of ores is reviewed on a generic basis with particular reference to some of the confusions which can arise due to lack of consistency or common logic in the use of exclusion, exemption and clearance. The difference in exclusion and exemption are challenged by comparing doses received in high background radiation areas and the doses received from a mining practice. The common principle of risk to the human species is not applied consistently. The differences between IAEA recommendations and local regulatory conditions are compared, and the use of exemption levels as clearance levels is considered. A case study on management of mine tailings is presented with special focus on the use of clearance levels. In all areas of review the interpretation of regulation is subject to confusion resulting from inconsistencies which can distort free market economics. (author).
This poster presentation discussed the management of environmental risks. It began with the methodology for the proper risk analysis, and its application to a liquefied sulphur dioxide reservoir. The authors described the risks presented by sulphur dioxide on human health and followed with the risk assessment method. The authors then discussed environmental risk management as it relates to the mining industry, with a special emphasis on tailings. Some examples of remedial action implemented on various waste rock piles were also presented. The conclusions emphasized the possible consequences of a major liquefied sulphur dioxide accident and the need to prepare for them by developing emergency plans, identifying remedial actions, and ensuring the proper training of all employees. 81 figs.
Many hoarding rodents use burrows not only for dwelling and protection from natural enemies, but also for food storage. However, little is known how burrows used by scatter-hoarding animals influence their foraging behaviors. In addition, handling time for a given food item has a fundamental impact on hoarding strategies of these hoarding animals: food items with longer handling time are more likely to be hoarded due to increasing predation risk because the animals spend more time outside their burrows if they consumed such food. By providing with two types of artificial burrows (aboveground vs. underground) and two types of food items (i.e. seeds) with contrasting handling times, we investigated how burrow condition and handling time co-influence hoarding strategies of a key scatter-hoard...
In the present study, a new measurement technique which uses a ultrasonic transmission signals in order to determine the vertical two phase flow pattern even under high pressure condition. The ultrasonic measurement system developed in the present study not only provides the measurement functions required for the determination of vertical two phase flow pattern but also makes the real time determination possible. The developed ultrasonic measurement system accurately determined the various vertical two phase flow patterns such as bubbly, slug, churn, annular flow etc. In addition to the determination of flow patterns, qualitative informations for each flow pattern can be obtained, which include void fraction in bubbly flow, length of slug bubble and liquid tail characteristics in slug flow, and stable or transient condition of flow pattern, etc. 13 refs., 24 figs., 3 tabs. (Author)
In this, the last of a series of three papers, we discuss a method of forming iron phosphate ceramics by a reduction process. We report the formation of iron oxide ceramics by reducing hematite with iron in a phosphoric acid solution. The reaction results in a rapid-setting ceramic (at room temperature) with a compressive strength of 3700 psi and a density of 1.7 g/cm{sup 3}. Although the exact mineral form of the binder is difficult to determine because it is mostly amorphous and hence is not amenable to X-ray diffraction analyses, this material is expected to consist of iron hydrophosphates. The reduction process is very useful in recycling several industrial wastes that are rich in hematite, including iron mine tailings, red mud (a caustic waste from the alumina industry), and machining swarfs. Formation of ceramics with red mud and swarfs is also discussed.
Most active pharmaceutical ingredients (API) exhibit particle size distributions with some degrees of asymmetry deviating from log-normality. A new log-skew-normal (L-S-N) distribution model is proposed for a systematic comparison of the asymmetry effect on content uniformity. The new model originated from the S-N model used by Azzalini gives a close approximation to real API particle size distribution. Monte-Carlo method was employed to simulate the dosage potency distribution. A high risk of over potency is uncovered when either the dose is low or API particle size distribution is positively skewed. This is due to the formation of pseudo heavy tail in potency distribution that decays slower than exponentially. Nomographs of API particle size versus dosage strength were constructed with a...
This report presents the results of a study dealing with the homogeneous recycling of either Pu or Pu+Np or Pu+Np+Am or Pu+Np+Am+Cm in PWRs using MOX-UE fuel, i.e. standard MOX fuel with a U235 enriched uranium support instead of the standard tail uranium (0.25%) for standard MOX fuel. This approach allows to multirecycle Pu or TRU (Pu+MA) as long as U235 is available, by keeping the Pu or TRU content in the fuel constant and at a value ensuring a negative moderator void coefficient (i.e. the loss of the coolant brings imperatively the reactor to a subcritical state). Once this value is determined, the U235 enrichment of the MOX-UE fuel is adjusted in order to reach the target burnup (51 GWd/t in this study).
FastSLAM is a framework for simultaneous localization using a Rao-Blackwellized particle filter. In FastSLAM, particle filter is used for the mobile robot pose (position and orientation) estimation, and an Extended Kalman Filter (EKF) is used for the feature location's estimation. However, FastSLAM degenerates over time. This degeneracy is due to the fact that a particle set estimating the pose of the robot loses its diversity. One of the main reasons for loosing particle diversity in FastSLAM is sample impoverishment. It occurs when likelihood lies in the tail of the proposal distribution. In this case, most of particle weights are insignificant. Another problem of FastSLAM relates to the design of an extended Kalman filter for landmark position's estimation. The performance of the EKF and the quality of the estimation depends heavily on correct a priori knowledge of the process and measurement noise covariance matrices (Q and R) that are in most applications ...
The growth of stoichiometric and non-stoichiometric silicon nitride films was studied experimentally on 100 mm silicon wafers by batch depositions from the dichlorosilane (SiH{sub 2}Cl{sub 2})-ammonia (NH{sub 3}) system in a hot-wall horizontal low pressure chemical vapor deposition (LPCVD) reactor. The growth kinetics were discussed in terms of the Langmuir adsorption isotherm. The kinetic parameters were determined by comparing the experimental data with a one-dimensional simulation model. The decomposition of NH{sub 3} at high temperatures was included in the simulation procedure. When the SiH{sub 2}Cl{sub 2}:NH{sub 3} ratios were greater than 1.5, a quantity higher than the thermodynamic critical values above which Si-rich nitride films begin to deposit, various SiN{sub x} films with x < 4/3 were obtained. The composition of the SiN{sub x} films was found to vary along the LPCVD reactor. The film stoichiometry was ...
After pioneering work in the 1980s, plasma-based ion implantation (PBII) and plasma-based ion implantation and deposition (PBIID) can now be considered mature technologies for surface modification and thin film deposition. This review starts by looking at the historical development and recalling the basic ideas of PBII. Advantages and disadvantages are compared to conventional ion beam implantation and physical vapor deposition for PBII and PBIID, respectively, followed by a summary of the physics of sheath dynamics, plasma and pulse specifications, plasma diagnostics, and process modeling. The review moves on to technology considerations for plasma sources and process reactors. PBII surface modification and PBIID coatings are applied in a wide range of situations. They include the by-now traditional tribological applications of reducing wear and corrosion through the formation of hard, tough, smooth, low-friction and ...
Crystalline and non-crystalline iron oxide (#alpha#-Fe_2O_3) thin films were obtained by spray pyrolysis onto glass substrate at different temperatures. The results of X-ray diffraction showed that with increasing the deposition time, the film structure changed from non-crystalline to crystalline at the same substrate temperature. At different substrate temperatures and low deposition times (5 min), iron oxide appears almost in non-crystalline form. With rising the substrate temperature and deposition time, the crystallinity was improved. The effect of substrate temperature as well as deposition time on the optical features (absorption coefficient and bandgap) and optical constants of these films has been investigated. Optical constants of the films were determined from spectrophotometric measurement of reflectance and transmittance. Analysis of the results showed that, for non-crystalline iron oxide ...
A general criterion has been suggested for deep geological repositories containing spent fuel - the repositories should impose no greater radiological risk than due to naturally occurring uranium deposits. The following analysis investigates the rationale of that suggestion and determines whether current expectations of spent-fuel repository performance are consistent with such a criterion. In this study, reference spent-fuel repositories were compared to natural uranium-ore deposits. Comparisons were based on intrinsic characteristics, such as radionuclide inventory, depth, proximity to aquifers, and regional distribution, and actual and potential radiological consequences that are now occurring from some ore deposits and that may eventually occur from repositories and other ore deposits. The comparison results show that the repositories are quite comparable to the natural ore ...
Over one-third of Canada's coal resources occurs in the southern Canadian Rocky Mountains, with major deposits in the Front Ranges, Inner Foothills and Outer Foothills. In the Front Ranges, deposits of metallurgical and thermal, high-volatile bituminous to semi-anthracite coal occur in the Late Jurassic-Early Cretaceous Mist Mountain Formation. In the Inner Foothills of northeastern British Columbia and west-central Alberta, resources of metallurgical and thermal medium- and low-volatile bituminous coal occur in Early Cretaceous strata of the Gething and Gates Formations. In the Outer Foothills resources of thermal, high-volatile bituminous coal occur in Late Cretaceous and Paleocene strata of the Belly River Coalspur and Paskapoo Formations. The major deposits of the Front Ranges and Inner Foothills accumulated within the coastal plains of the Fernie and Moosebar-Clearwater seas. Shorelines prograded to the north ...
Nanocrystalline chromium oxynitride films were deposited by reactive RF magnetron sputtering of metallic chromium target in argon and helium atmospheres. The paper deals with consequence of increase in oxygen partial pressure on structural, hydrophobic and optical properties of chromium oxynitride films. The film stoichiometry changes from CrN and Cr2O3 to only Cr2O3 with increase in oxygen partial pressure as evident from X-Ray Diffraction analysis in both cases. The average crystallite size decreases with increase in oxygen partial pressure for both gas atmospheres. The thickness calculated from transmission data and surface profilometer are in good harmony with each other. The deposited films are hydrophobic by nature and the contact angle of the films varies as a function of surface ro...
Pinealectomy completely prevented gonadal regression as well as reduction in body weight and white adipose tissue content of the gonadal and retroperitoneal fat deposits in male meadow voles transferred from long to short day lengths. Pineal influences on pelage characteristics depended on which parameter was assessed. For instance, the increase in guard hair length observed in short-day control voles was blocked by pinealectomy; however, a similar increase in underhair length was unaffected by removal of the pineal gland. Photoperiod-dependent changes in fat deposition, testicular activity, and guard hair length presumably rely on altered pineal secretory activity to transduce the effects of day length on the neuroendocrine axis; however, mechanisms independent of pineal activity may be capable of mediating photoperiodic control of underhair growth. PMID:2979644
The performance of Ag-promoted Pd/Al2O3 catalysts, which were prepared by the selective deposition of Ag onto Pd using a surface redox (SR) method, during acetylene hydrogenation was compared with that of catalysts prepared by impregnation. The Pd surface was more effectively modified with Ag added by SR, even when small amounts of Ag were added. The catalyst prepared by SR showed a higher ethylene selectivity than the one prepared by impregnation, because SR allowed both the preferential deposition of Ag on the low-coordination sites of Pd and a greater electronic modification of Pd by Ag.
Morphology of castellated Be tiles from the belt limiter exposed to the JET plasma for 56,000 s was examined on both sides of castellated grooves, on plasma-facing and side surfaces of the tiles. The essential results are (i) deuterium retention in the castellated grooves and in other locations is associated with co-deposition of carbon; (ii) the decay length of deposition in the castellation is around 1.5 mm; (iii) no deuterium is detected in bulk Be; (iv) bridging of gaps by molten beryllium occurred but gaps were not filled with Be; (v) on side surfaces of the tiles the formation of BeO layer was detected at a distance of 20 mm and more from the plasma-facing surface. The consequences for a long-term operation of a reactor-class device with several different plasma-facing materials are addressed.
Yttria stabilized zirconia (YSZ) with 8 mol% Y was deposited by reactive magnetron sputtering onto oxidized (100) silicon substrates. It was possible to switch film texture from (111) to (200) by applying a strong RF substrate bias. Transmission electron microscopy showed that the film deposited under bias is porous and exhibits nanoscaled grains, whereas the film deposited without bias is dense and columnar. The ionic conductivity as a function of temperature revealed an activation energy of 1.04 eV. The mechanical stress could be tuned to low values by thermal post-annealing. Using the dense (111) film as electrolyte layer, and the porous (200) film as an interlayer to a porous Pt anode, an open circuit voltage of 0.85 V was obtained in a micro machined fuel cell structure.
Abstract Smoke is a mixture of toxic gases and suspended particulate matter of solids and liquids that evolves from a fire of flammable materials. This article presents real-time consequence modeling to track the concentration of individual species in smoke as well as its soot deposition. In the modeling process presented, the burning rate or vapor mass is fed into a combustion model in which the combustion of products has been identified and quantified along with the temperature of the fire. The output of the combustion model is the smoke that will be dispersed into the ambient. The fire geometry, which depends on the type of fire (e.g., pool or flare), is identified. A dispersion model with the capability of determining particulate deposition is then used for tracking the smoke plume. Th...
The in-depth distribution of phases in c-BN films deposited by Ion Beam Assisted Deposition (IBAD) at two different ion energy values (300 and 600 eV) was investigated using the quantitative IR transmission measurements and the HREM technique. Whatever the value of the studied ion energies, the characteristic layered morphology of c-BN film is observed including the interfacial sp"2 zone between the substrate and the c-BN volume. In the case of 600 eV ion energy, this interfacial zone is less well-defined in comparison with 300 eV ion energy and the corresponding thickness is more important. Furthermore, the h-BN phase is more diluted within the c-BN film volume showing that the purest phase concentration of c-BN is found for the lowest ion energy, i.e., 300 eV.
Nano structured carbon nitride thin films were deposited at different RF powers in the range of 50 W to 225 W and constant gas ratio of (argon: nitrogen) Ar:N_2 by RF magnetron sputtering. The atomic percentage of Nitrogen: Carbon (N/C) content and impedance of the films increased from 14.36% to 22.31% and 9 x 10"-"1 #OMEGA# to 7 x 10"5 #OMEGA# respectively with increase in RF power. The hardness of the deposited films increased from 3.12 GPa to 13.12 GPa. The increase in sp"3 hybridized C-N sites and decrease of grain size with increase in RF power is responsible for such variation of observed mechanical and electrical properties.
The Model of Acidification of Groundwaters in Catchments (MAGIC) was used to simulate the impact of acidifying deposition and future recovery at the Gaardsjoen Covered Catchment Experiment, at a number of hypothetical stations defined by statistical variation of the Gaardsjoen data and at 20 forest monitoring sites in Southern Sweden. For the future predictions a decrease of sulphur deposition of more than 70% was assumed. This assumption is based on a full implementation of the agreements made under the second sulphur protocol from 1994. The modelled impact of reduced deposition on the soils and on the runoff waters was discussed. To complement the discussion on long-term trends in future run-off chemistry, data from Gaardsjoen has been used to asses the risk for short-term acid runoff episodes 26 refs, 23 figs, 7 tabs
Abstract The Jebel Ressas Pb-Zn deposits in North-Eastern Tunisia occur mainly as open-space fillings (lodes, tectonic breccia cements) in bioclastic limestones of the Upper Jurassic Ressas Formation and along the contact of this formation with Triassic rocks. The galena-sphalerite association and their alteration products (cerussite, hemimorphite, hydrozincite) are set within a calcite gangue. The Triassic rocks exhibit enrichments in trace metals, namely Pb, Co and Cd enrichment in clays and Pb, Zn, Cd, Co and Cr enrichment in carbonates, suggesting that the Triassic rocks have interacted with the ore-bearing fluids associated with the Jebel Ressas Pb-Zn deposits. The 18O content of calcite associated with the Pb-Zn mineralization suggests that it is likely to have precipitated from a fl...
Microcrystalline silicon carbide ({mu}c-SiC) was prepared at low substrate temperatures using Hot Wire chemical vapor deposition (HWCVD). High crystalline volume fractions were achieved at high hydrogen dilution and high deposition pressure. Without intentional doping, such material shows high dark conductivity and high optical absorption below the band gap. The material prepared at low deposition pressure or low hydrogen dilution, on the other hand, shows much lower conductivity and sub-gap absorption, but high spin densities up to 5 x 10{sup 19} cm{sup -3}. This high absorption can be attributed to free carriers, different to {mu}c-Si:H where a correlation between the sub-gap absorption and the spin density is observed.
Tokamaks with sufficiently strong supplementary heating develop non-Maxwellian electron velocity distributions. Because the absorption of electron cyclotron power is proportional to #nabla#_Vf, even small deviations from a Maxwellian distribution can significantly affect power deposition. Following an approach used to study microinstabilities in a plasma with an arbitrary, numerically specified, electron distribution, we have developed a computational module to study electron cyclotron power deposition in plasmas that have distributions motivated by those in actual tokamaks. Also, we compare the deposition results obtained using an energy balance approach with those obtained using a Taylor expansion of the dielectric tensor. We illustrate the limitations of the latter approach.
Palladium deposition on Pt(110) electrodes was studied. Differently from Pt(111) and Pt(100), first and further layers cannot be distinguished in this case only through the voltammetric behavior of hydrogen and anion adsorption. The potential of zero total charge (pztc) was determined as a function of the amount of deposited Pd using CO charge displacement experiments and voltammetric curves. The variation of the voltammetric charge due to hydrogen and anion adsorption has been followed during Pd deposition. The voltammetric charge between 0.06 and 0.4V first decreases to a minimum, then increases and finally becomes stable, suggesting that the surface is finally covered with a Pd multilayer. The pztc and CO oxidation charge show similar behavior. CO oxidation, NO reduction and Cu UPD were...
In this work the DC and AC characteristics for metal-LB film-metal structures deposited by a standard Langmuir-Blodgett film deposition technique are investigated. The conduction mechanism has been studied for a thin film structure in which a calix[4]arene substituted with carboxylic acid groups has been deposited alternately with a calix[4]arene molecule substituted with amine groups. This LB film structure shows a typical insulating behaviour for low voltage values and the Schottky effect becomes dominant when the voltage increases. The conductivity at low voltage values was found to be 1.34x10^-^1^3Scm^-^1. The height of the potential barrier was determined to be 1.65eV for this alternate layer LB film system.
TiB{sub 2} appears to be a promising material for the wear protection in various tribological systems, e.g. the diecasting of Al. This study focuses on the development of titanium boride coatings deposited by PACVD, a deposition method which is most suitable for the coating of substrates with complex shapes. All layers analysed are very smooth and exhibit a quasi-amorphous fracture surface. XRD and TEM analysis indicate a nanocrystalline structure with grain sizes in the order of 2 nm. The diffraction patterns can well be correlated to titanium diboride. WDS reveals an over stoichiometric B/Ti ratio. The layer hardness reaches the value of 33 GPa and the critical load in scratch tests rises to 35 N. Neither 100Cr6 nor Al as a counterpart in pin-on-disk tests leads to wear of the coating. (orig.)
The Jaduguda U (?Cu?Fe) deposit in the Singhbhum shear zone has been the most productive uranium deposit in India. Pyrite occurs as disseminated grains or in sulphide stringers and veins in the ore zone. Veins, both concordant and discordant to the pervasive foliation, are mineralogically either simple comprising pyrite ? chalcopyrite or complex comprising pyrite + chalcopyrite + pentlandite + millerite. Nickel-sulphide minerals, though fairly common in concordant veins, are very rare in the discordant veins. Pyrite in Ni-sulphide association is commonly replaced by pentlandite at the grain boundary or along micro-cracks. Based on concentrations of Co and Ni, pyrite is classified as: type-A ? high Co (up to 30800?ppm), no/low Ni; type-B ? moderate Co (up to 16500?ppm) and moderate to high ...
A calorimetric sensor with several novel design features has been developed. These sensors will provide an accurate sampling of thermal power density and energy deposition from proton beams incident on target components of accelerator-based systems, such as the Accelerator Production of Tritium Project (APT) and the Spallation Neutron Source (SNS). A small, solid slug (volume = 0.347 cc) of target material is suspended by kevlar fibers and surrounded by an adiabatic enclosure in an insulating vacuum canister of stainless steel construction. The slug is in thermal contact with a low-mass, calibrated, 100-k{Omega} thermistor. Power deposition caused by the passage of radiation through the slug is calculated from the rate of temperature rise of the slug. The authors have chosen slugs composed of Pb, Al, and LiAl.
Villarrica (Chile) is one of the most active volcanoes in South America having erupted about 60 times in the last 460years. Although its historical eruptive activity has been mainly effusive and weakly explosive, it had strong explosive behaviour in postglacial times. Chaimilla (<3.1ka) is one of the best exposed and widely dispersed pyroclastic deposits, related to both fall and flow activity. The deposit is dispersed over an area of 250km^2 and consists of 8 units (A-H) which were grouped into four sequences. Stratigraphic data suggest that the eruption had a relatively short duration and evolved from i) an Opening phase, dispersing ash, lapilli clasts, accretionary lapilli, blocks and bombs, to ii) a Pulsatory phase, originating a series of magmatic explosions, to iii) a Collapsing phas...
This SBIR Phase I developed neutron detectors made from gallium arsenide (GaAs) p-type/ intrinsic/n-type (P-I-N) diodes grown by metalorganic chemical vapor deposition (MOCVD) onto semi-insulating (S1) bulk GaAs wafers. A layer of isotonically enriched boron-10 evaporated onto the front surface serves to convert incoming neutrons into lithium ions and a 1.47 MeV alpha particle which creates electron-hole pairs that are detected by the GaAs diode. Various thicknesses of ''intrinsic'' (I) undoped GaAs were tested, as was use of a back-surface field (BSF) formed from a layer of Al{sub x}Ga{sub 1-x}As. Schottky-barrier diodes formed from the same structures without the p+ GaAs top layer were tested as a comparison. After mesa etching and application of contacts, devices were tested in visible light before application of the boron coating. Internal quantum efficiency (IQE) of the best diode near the GaAs bandedge is over 90%. The ...
Both soil and plant samples of nine different plant species grown in soils from southeastern China contaminated with uranium mine tailings were analyzed for the plant uptake and translocation of "2"3"8U, "2"2"6Ra and "2"3"2Th. Substantial differences were observed in the soil-plant transfer factor (TF) among these radionuclides and plant species. Lupine (Lupinus albus) exhibited the highest uptake of "2"3"8U (TF value of 3.7x10"-"2), while Chinese mustard (Brassica chinensis) had the least (0.5x10"-"2). However, in the case of "2"2"6Ra and "2"3"2Th, the highest TFs were observed for white clover (Trifolium pratense) (3.4x10"-"2) and ryegrass (Lolium perenne) (2.1x10"-"3), respectively. "2"3"2Th in the tailings/soil mixture was less available for plant uptake than "2"2"6Ra or "2"3"8U, and this was especially evident for Chinese mustard and corn (Zea mays). The root/shoot (R/S) ratios obtained for different plants and radionuclides shown that ...
A modified accumulator was devised to measure surface radon flux from porous media. It consists of a collector hood accumulator with a homogenizer pump and a pressure balancer. The latter was used to compensate for any pressure changes produced during sample withdrawl and hence eliminate additional radon transport from media. Errors resulting from radon back diffusion due to decreasing concentration gradient with time across the interface were eliminated by measuring radon concentrations in the accumulator for two different periods of time and calculating the true radon flux, J(o), from the solution of a time-dependent radon transport equation. Core samples from the observation site were withdrawn for laboratory determination of porosity, moisture content, bulk and grain densities, Ra-226 source concentration and the fraction of Rn-222 produced in the void volume. The data were used to calculate the radon diffusion coefficient for the media. Using the present method, the true value of ...
Designer natriuretic peptides (NPs) represent an active area of drug development. In canine and human studies, the designer natriuretic peptide CD-NP demonstrated more desirable therapeutic potential than recombinant B-type NP (BNP), which is known as nesiritide and is approved for treatment of acute decompensated heart failure. However, why CD-NP is more effective than BNP is not known. We previously reported that CD-NP is a poorer activator of human guanylyl cyclase-A (GC-A) and a better activator of human guanylyl cyclase-B than BNP. Here, guanylyl cyclase bioassays were used to compare the susceptibility of CD-NP verses ANP, BNP, CNP and DNP to inactivation by human kidney membranes. The half time (t(1/2)) for CD-NP inactivation was increased by factors of 13, 3 and 4 compared to ANP, BNP and CNP, respectively, when measured in the same assay. Surprisingly, DNP failed to undergo complete inactivation and was the most degradation resistant of the peptides tested. The neutral ...
A modified accumulator was devised to measure surface radon flux from porous media. It consists of a collector hood accumulator with a homogenizer pump and a pressure balancer. The latter was used to compensate for any pressure changes produced during sample withdrawl and hence eliminate additional radon transport from media. Errors resulting from radon back diffusion due to decreasing concentration gradient with time across the interface were eliminated by measuring radon concentrations in the accumulator for two different periods of time and calculating the true radon flux, J(o), from the solution of a time-dependent radon transport equation. Core samples from the observation site were withdrawn for laboratory determination of pkrosity, moisture content, bulk and grain densities, Ra-226 source concentration and the fraction of Rn-222 produced in the void volume. The data were used to calculate the radon diffusion coefficient for the media. Using the present method, the true value of ...