An antigen-antibody system of polystyrene tubes coated with immunoglobulin antibody was used for quantitating immunoglobulins. A similar radioimmunoassay method was adapted for a viral antigen-antibody...Full Text Available
DNA antoantibodies in serum will bind to antigen-coated polystyrene tubes and can be detected by radiolabelled anti-immunoglobulin. The method is quantitative, gives information on the antibody class...Full Text Available
This paper advances hypotheses on the chemistry of the interaction of thorium and yttrium with organic-inorganic salts of molybdenum polyacids. On the basis of an analysis of the data of an adsorption experiment and the quantitative relationships that follow from the law of mass action, it is shown that thorium is absorbed by the solidphase by coprecipitation with the participation of complex formation, while the coprecipitation of yttrium with salts of polyacids is due to a reaction of ion exchange chemisorption.
Here we reported a two-step procedure for preparing a novel polymeric based solid-solidphase change heat storage material. Firstly, a copolymer monomer containing a polyethylene glycol monomethyl ether (MPEG) phase change unit and a vinyl unit was synthesized via the modification of hydrogen group of MPEG. Secondly, by copolymerization of the copolymer monomer and phenyl ethylene, a novel polymeric based solid-solidphase change heat storage material was prepared. The composition, structure and properties of the novel polymeric based solid-solidphase change material were characterized by IR, "1H NMR, DSC, WAXD, and POM, respectively. The results show that the novel polymeric based solid-solidphase change material possesses of excellent crystal properties and high phase change ...
Extra-fine powdered activated charcoal has been used as stationary phase (coating layer) in solid-phase microextraction (SPME). The efficiency and reliability of the prepared device have been investigated for the extraction of some volatile organic compounds such as benzene, toluene, ethylbenzene and xylene isomers (BTEX) from the headspace of water samples. Monitoring of the extracted compounds and further quantitative analysis of the real samples have been performed by capillary GC-FID. Effects of several factors such as temperature, addition of salt, and stirring speed on extraction efficiency and exposure time have been studied. Under optimum conditions, extraction recoveries for these compounds from 50 mL water were >95%. The calibration graphs were linear in the range 5 to 10{sup 4} pg mL{sup -1} and the detection limit for each BTEX compound was 1.5-2 pg mL{sup -1}. The results obtained by use of this porous layer ...
The quantitative imaging of a phase object using 16 keV x-rays is reported. The theoretical basis of the techniques is presented along with its implementation using a synchrotron x-ray source. It is found that the phase image is in quantitative agreement with independent measurements of the object. 13 refs., 5 figs.
... and high-quality photospheric-phase Type II SN spectra to constrain core- collapse SN explosions, massive star evolution, and distances in the Universe ...
Phosphoramidite reagents can phosphitylate guanine bases at the O6-position during solidphase synthesis and serious chain cleavage occurs if the base phosphitylation is not eliminated before the iodine/water...Full Text Available
A detailed comparative assessment was made of the use of solid-phase-coupled antibodies in radioimmunoassay, by using an assay for human placental lactogen as a model system. The major advantages of...Full Text Available
A solid-phase radioimmunoassay employing 125I-labeled enterotoxins and polystyrene tubes coated with specific antibody has been developed for assaying the relative concentrations of antibodies...Full Text Available
A method for the quantitative determination of atmospheric hydroperoxyl radical comprising: (a) contacting a liquid phase atmospheric sample with a chemiluminescent compound which luminesces on contact with hydroperoxyl radical; (b) determining luminescence intensity from the liquid phase atmospheric sample; and (c) comparing said luminescence intensity from the liquid phase atmospheric sample to a standard luminescence intensity for hydroperoxyl radical. An apparatus for automating the method is also included.
Equilibrium and energy equations have been developed in describing the solid-fluid transition zone during the melting and solidification of the binary alloys. Due to the existence of the transition region exhibited both solid and fluid phases at the same material point from continuum point of view, mixture theory was utilized to analyze the region. Unlike the Stefan problem, the latent heat due to the phase change appears as a source term in the heat equation. The molten fluid is treated as a thermoviscous and incompressible fluid, whereas the solid is thermoviscoplastic described by the Bodner-Partom/Walker type of constitutive equations. Thermal mechanical behaviors of the solid and the fluid phases are determined separately because of insignificant mechanical interactions between them. Volume fractions of the phases ...
Having simple and highly symmetric structure, solid hydrogen is a useful matrix on the study of radiation-chemical processes in solidphase which have been less understood in previous studies. We have found three outstanding findings: resonance effects on the tunneling reaction H+H{sub 2} {yields} H{sub 2} + H, effects of pressure on the dissociation and recombination of H{sub 2} molecules in solid hydrogen, and high-resolution ESR spectroscopy using a solid parahydrogen matrix. (author)
An analytical method was developed for the determination of eleven agrochemicals [abamectin (as B1a), bifenazate, bifenthrin, carfentrazone-ethyl, cymoxanil, hexythiazox, imidacloprid, mefenoxam, pymetrozine, quinoxyfen, and trifloxystrobin] in dried hops. The method utilized polymeric and NH2 solidphase extraction (SPE) column cleanups and liquid chromatography with mass spectrometry (LC-MS/MS). Method validation and concurrent recoveries from untreated dried hops ranged from 71 to 126% for all compounds over three levels of fortification (0.10, 1.0, and 10.0 ppm). Commercially grown hop samples collected from several field sites had detectable residues of bifenazate, bifenthrin, hexythiazox, and quinoxyfen. The control sample used was free of contamination below the 0.050 ppm level for all agrochemicals of interest. The limit of quantitation and limit of detection for all compounds were 0.10 and 0.050 ppm, respectively. ...
The classical Stefan theory for the melting of a solid or the freezing of a liquid is too simplistic to describe phenomena such as supercooling, in which a liquid supports temperatures below its freezing point, or superheating, the analog for solids, or d...
This paper deals with the energy required to separate ethanol from an aqueous solution in a distillation column containing a solidphase. The solidphases evaluated consisted of either an amylatious (ground corn) or a cellulose (sugar cane bagasse) absorber whit particle sizes smaller than 4 mm. The water-retention capacity of each solidphase was measured by passing vapors or ethanol-water mixtures through the solidphase. When starting with initial concentrations bellow the azeotropic point, ethanol concentrations up to 99,5% (on corn) and 97,2% (on sugar cane) were achieved. The water content was evaluated potentiometrically (Karl`Fischer). Regarding the 2-4 mm ground corn solidphase column, the energy consumed was estimated to be reduced by 15,6% and 60% (by weight) ...
We report on a hard X-ray phase imaging microscopy (a phase-difference microscopy) that consists of an objective and a transmission grating. The simple optical system provides a quantitativephase image, and does not need a wave field mostly coherent on the objective. Our method has a spatial resolution almost same as that of the absorption contrast microscope image obtained by removing the grating. We demonstrate how our approach provides a phase image from experimentally obtained images. Our approach is attractive for easily appending a quantitativephase-sensitive mode to normal X-ray microscopes, and has potentially broad applications in biology and material sciences.
The distribution of the alkaline earth elements strontium and barium between the solidphases of phosphates of transition elements of group 4 and chloride melts was studied. The distribution coefficients of strontium and barium were found at T = 700-800/sup 0/C. Phosphates of the type NaM/sub 2//sup (IV)/(PO/sub 4/)/sub 3/, where M/sub (IV)/ represents titanium, zirconium, and hafnium, were used as the solidphases. It was established that there is an enrichment of the precipitates with the distributed components. The distribution coefficient depends on the nature of the solidphase and the temperature. It was suggested that M/sup (II)/ x M/sub 4//sup (IV)/(PO/sub 4/)/sub 6/ is formed in processes of distribution, where M/sup (II)/ represents Sr, Ba.
Despite their simplicity, diatomic molecules of first row elements can exhibit very complex phase diagrams. Determination of the phase diagrams can be further complicated by the existence of hysteretic molecular phases that can be observed over large regions of coexistence. Here we present evidence for a previously unreported molecular phase of nitrogen existing at room temperature at least over the range of 33-74 GPa. Our measurements show that sample history may have a significant impact on the thermodynamic states accessed by the molecular nitrogen solid and, by extension, also on the established phase diagram.
Corrosion testings of model alloys, corresponding by chemical composition to simple and complex-alloyed #gamma#- and #gamma#'-phases of nickel heat-resistant alloys are conducted in sodium sulfate and chloride melts. It is ascertained that heat resistant nickel alloys containing over 50 % of hardening #gamma#'-phase, are subject to disastrous sulfide corrosion (SC). Resistance against SC alloys containing below 50 % of #gamma#'-phase is determined by the resistance of #gamma#-solid solution. 10 refs., 3 figs., 2 tabs.
The physical methods were used to study the decomposition of a metastable #beta#-solid solution in the VT22 two-phase titanium alloy. It is shown that the martensitic #beta# #-># #alpha#'' transformation in doped-element depleted microvolumes of the #beta#-solid solution are dominanted and the long-time multistage decomposition through a number of intermediate states in others.
The quantitative experimental uncertainty in the structure of fully hydrated, biologically relevant, fluid (Lα) phase lipid bilayers has been too large to...Full Text Available
A fluid-phase immunoradiometric assay has been developed which identifies an antigen on the Factor VIII (antihemophilic factor) procoagulant protein. This sensitive and quantitative assay is not influenced...Full Text Available
Quantitative metallography is often used to confirm the proper processing of aerospace metallic materials. A microstructural feature of great importance for titanium alloys processed in the alpha-beta phase field is the volume fraction of primary alpha. S...
The 52 papers discuss the following subjects: 1. Preparation and structural development; 2. Structural constitution; 3. Structural formation and phase transition; 4. Structure and mechanical properties; 5. Structural formation of metallic and nonmetallic materials; 6. Quantitative metallography, and 7. Quality assurance.
A localization criterion for the crystal-liquid phase transition (PT) is suggested, according to which the PT starts when the ratio E d/k B T reaches a boundary value E d(s)/k B T m, above which a solidphase, and below which, a liquid phase is located in the phase diagram. Here, E d is the energy of the delocalization of an atom, k B is the Boltzmann constant, T is the temperature, and E d(s) is the energy of delocalization for the solidphase at the melting point T m. It is shown that this criterion extends the Lindemann criterion of melting to the case of crystallization, and the L?ven criterion of crystallization to the case of melting. It is shown that the localization criterion suggested is applicable both for the normally melting substances and for the substances melting with a decr...
A localization criterion is proposed for the crystal-liquid phase transition (PT). According to this criterion, the PT begins when the E d/k b T ratio reaches a boundary value E d(s)/k b T m such that a solidphase is present above it and a liquid phase is present below it in a phase diagram. Here, E d is the energy of atom delocalization, k b is the Boltzmann constant, T is the temperature, and E d(s) is the delocalization energy for a solidphase at melting point T m. This criterion is shown to generalize the Lindemann criterion of melting to the case of crystallization and the L?ven criterion of crystallization to the case of melting. This localization criterion is found to be applicable for both normally melting substances and substances that melt with a decrease in the specific volume...
The aim of this work is to the application of a methodology to evaluate the energy associated to the industrial solid wastes in the metropolitan region of Campinas. The methodological route proposed is: the characterization of the research area and the production/management of the industrial solid wastes; the energetic classification and the qualitative/quantitative research of the energy associated to the industrial solid wastes; and, the valuation of the applicability of the energetic utilization mechanisms proposed to the region. This methodology when applied at the Campinas metropolitan region proved to be valid and it resulted in a synthetically presentation of the social and environmental reality of the industrial sector and the destination of the wastes, as well as it indicated the potentialities related to the energetic utilization of the industrial solid waste in the ...
Experimental data on A-15 binary phases (the lattice parameter dependence on composition, phase diagrams, etc.) have been considered and the so-called ''compounds with A-15 structure'' are shown to be solid solutions of element substitution in the structure of A-15 type. Values of lattice parameter and atomic volume of A-15 modifications for 21 elements have been obtained (for Zr, W, Nb, Mo, V in particular). There has been shown the possibility of calculation of atomic volumes and lattice parameters of A-15 binary phases at the lack of direct experimental data. The essential role of atomic volume relations of different phases has been observed for the estimation of stability conditions of A-15 phase.
Experimental data on A-15 binary phases (the lattice parameter dependence on composition, phase diagrams, etc.) have been considered and the so-called ''compounds with A-15 structure'' are shown to be solid solutions of element substitution in the structure of A-15 type. Values of lattice parameter and atomic volume of A-15 modifications for 21 elements have been obtained (for Zr, W, Nb, Mo, V in particular). There has been shown the possibility of calculation of atomic volumes and lattice parameters of A-15 binary phases at the lack of direct experimental data. The essential role of atomic volume relations of different phases has been observed for the estimation of stability conditions of A-15 phase.
It is shown that it is necessary to take into account locality of the analysis and to introduce additional corrections for partial capture of matrix and fluorescent subexcitation by matrix during quantitative X-ray spectral microanalysis of finely dispersed materials. Cast two-phase (#alpha#+#beta#) titanium alloy VT3-1 is chosen as an investigation object.
Results of X-ray investigations of solid normal hydrogen are presented. Temperature dependences of the lattice parameteps, molar volumes, linear and volume expansion coefficients in the 2K-Tsub(melt) temperature range are obtaiped. An essential n-H/sub 2/ expansion anisotropy in the premelting temperature region is pointed out. It is shown that the hexagonal lattice parameter ratios over the whole investigated temperature range is considerably higher than for solid parahydrogen. A considerable difference in thermal expansion of normal hydrogen and parahydrogen in the low temperature region is revealed. It is caused by contribuation of a rotational subsystem, increasing with the temperature decrease to crystal expansion. A detailed analysis of solid n-H/sub 2/ thermodynamic properties is conducted. The data testifying to the presence of isomorphous phase transformation in the solid ...
A number of different theoretical approaches have been used to model to atomic structure and properties of solid-liquid interfaces. Most calculations indicate that ordering occurs in the first several layers of the liquid, adjacent to the crystal surface. In contrast to the numerous theoretical investigations, there have been no direct experimental observations of the atomic structure of a solid-liquid interface for comparison. Saka et al. examined solid-liquid interfaces in In and In-Sb at lattice-fringe resolution in the TEM, but their data do not reveal information about the atomic structure of the liquid phase. The purpose of this study is to determine the atomic structure of a solid-liquid interface using a highly viscous supercooled liquid, i.e., a crystal-amorphous interface.
The n3 and n4 vibrational transitions of CH3 and CD3 isolated in solid parahydrogen were studied by high-resolution infrared spectroscopy. The radicals were produced by in situ UV photolysis of methyl iodides trapped in solid parahydrogen. The observed spectra showed clear rotational fine structures, which were subjected to further splitting due to the electrostatic field of solid parahydrogen. The molecular constants and crystal field parameters of the radicals in solid parahydrogen were determined by analyzing the spectral structures of the n3 and n4 transitions of CD3 by the crystal field theory. The rotational constants of the CD3 radical were found to be only a few percent smaller than those in the gas phase. The determined crystal field parameters indicated significant quantum effect...
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, Characterization of solid gums, sediments, and ...
In order to investigate interactions of (Ti,W)(C,N) and (Ti,Mo)(C,N) with binder metals solid/solid diffusion couples were annealed. These two-dimensional arrangements provide good access to phase reactions occurring upon sintering already in the solid state. It was found in (Ti,W)(C,N)/Co- and (Ti,W)(C,N)/Ni-based couples that the reaction zone is thinner in contact with Co than with Ni. It was also observed that the reaction rate with both Co and Ni is lower if nitrogen is added to the hard phases. Beside a thickness variation of the diffusion zones a change in the microstructure was found. At the interface of nitrogen-free hard phases in contact with Co elongated microstructural constituents are formed with the main axis perpendicular to the interface, while at the interface of nitrogen-containing hard phases these elongated microstructural constituents were ...
Concerning the transient phenomenon of solid-gas two-phase flow, an attempt was made to visualize and measure a flow phenomenon in which three-dimensional bubbles occurred, grew and collapsed in the vicinity of a gas injection nozzle while solid particles were circulating. Such a phenomenon could not or hardly be visualized and measured by conventional methods. Such two-phase flow was visualized using neutron radiography, its characteristics measured and the usefulness of the visualization by neutron radiography confirmed. For this purpose, three-dimensional fluidized bed vessels, rectangular or cylindrical-shaped, made of steel or aluminum sheet, were prepared. Polyethylene or glass beads were used as solid particles and activated carbon particles as the tracer. In the experiment, nitrogen gas was blown into the vessel from one nozzle and distributors provided at the bottom of the ...
An interferometric technique for hard X-rays is presented. It is based on two transmission gratings and a phase-stepping technique, and it provides separate radiographs of the phase and absorption profiles of bulk samples. Tomographic reconstruction yields quantitative three-dimensional maps of the X-ray refractive index and of the attenuation coefficient, with a spatial resolution down to a few microns. The method is mechanically robust, it requires little monochromaticity, and can be scaled up to large fields of view. These are important prerequisites for use with laboratory X-ray sources. Numerous applications ranging from wave front sensing to medical radiography are presently under investigation.
A heat storage compostion comprises sodium sulfate decahydrate as main component, a supercooling inhibitor, and a solid-liquid separation inhibitor. The composition is characterized in that hydraulic calcium sulfate and/or calcium sulfate dihydrate is contained as the solid-liquid separation inhibitor in an amount of 2-15 wt% base on the whole weight of the composition, whereby the solid-liquid separation, i.e. the sedimentation of the anhydrous sodium sulfate during the phase transition, is effectively prevented and the long-term stability is improved. The long-term stabilty of the composition can be more improved by addition of a silcia series of thickener.
An immunoassay employing 125I-labeled enterotoxin B and polystyrene tubes coated with specific antibody was used for assaying purified and crude enterotoxin. Antibody was adsorbed to untreated...Full Text Available
Product control procedures, the development of new technologies, and the extension of the applications of solid fuels are described. Hydrogasification and high-temperature Winkler gasification are discussed. The design and function of a continuous, semi-industrial plant for hydrogenating liquefaction in the sump phase are gone into. (MOS).
Nucleoside 3'-phosphoramidite and chlorophosphite reagents have been found to react with the lactam function of guanine. This reaction caused unsatisfactory results when oligodeoxyribonucleotides containing...Full Text Available
A serodiagnostic test has been developed for the detection of Plasmodium falciparum in infected blood. Using parasite antigens and infected red blood cells from in vitro...Full Text Available
Hepatitis B surface antigen (HBsAg) bound to immunoglobulin M (IgM) was detected in sera of HBsAg carriers by a radioimmunoassay based on selective absorption of the immunoglobulin on a solidphase...Full Text Available
BackgroundFor the detection of allergen-specific IgE in sera, solid-phase IgE-binding assays like the CAP test are commonly used. Although such immunochemical methods are very sensitive,...Full Text Available
Radionuclide (R) sorption from a solution (vapor) by freshly formed crystals with production of substitution solid solutions under different types of self-disordering is studied. Changes of self-defectiveness and macrodefectiveness with time and effect of radiation defects in the presence of P macroquantities are taken into account. An analysis for monodispersed sorbents is performed. It is shown that the achievement of equilibrium within a reasonable time in impurity-solidphase system depends on defectiveness which ensures a required level of the coefficient of impurity diffusion in sorbent crystals.
The results of calculated and experimental investigation of interphase isotopic exchange efficiency in countercurrent columns are given when separation processes of isotope mixtures are taken place with use of liquid-solid systems. Effect of liquid phase flow on transfer unit height in ion exchange separation of boron, lithium, nitrogen isotopes is considered. 40 refs.; 5 figs.
The phase stability of silicides of Ni, Pt and Pd in contact with single crystal or amorphous silicon is examined. The presence of a particular silicide phase is identified by X-ray diffraction, and Rutherford backscattering is used to study composition. It is concluded that Pt or Pd silicides are suitable for Schottky barriers. Layers of silicon can be grown quickly by solidphase epitaxy at temperatures of 300-500C and using an intermediate metal film. Experimental results are reported. Doped layers have been obtained which have electrical characteristics suitable for the junctions in solar cells. The effects of impurities and orientation of the substrate on the growth kinetics are discussed.
Three novel inosine-based dinuclear platinum complexes have been synthesized via a solid-phase strategy. In these compounds, the metal is linked both to the N-7 of the purine nucleus and to the terminal amine group of a hexylamine side chain installed on N-1. Cis- or trans- diamine as well as ethylenediamine ligands are coordinated to platinum along with a chloride. The synthesised complexes were tested against four different human tumor cell lines. One of these complexes proved to be more cytotoxic than cisplatin against the MCF7 cancer cell line in a short-term exposure assay.
The authors suggest a method of calculation of the isotherms of the spinodal and the heterogeneous equilibria in four-component systems in the framework of a unified thermodynamic model of the solution. The results of their calculations predict the existence of extended regions of immiscibility in the solidphase in the interval of temperatures usually used to obtain epitaxial layers of InAs/sub x/P/sub y/Sb/sub 1-x-y/ and AlAs/sub x/P/sub y/Sb/sub 1-x-y/.
The results of dielectric measurements in a wide frequency range have been used to find that solid solution samples on the basis of PbSc_1_/_2Sb_1_/_2O_3 have blurred phase transitions. The Curie-Weiss law is performed for different compositions in the temperature range 10-150 K above Curie point. The change of value and sign of the difference between Curie and Curie-Weiss temperatures is connected with the change of phase transition blurring degree.
The pM{sup '}-pC{sub H} diagrams allowed to determine the saturation and non-saturation zones of Lu(OH){sub 3} in solidphase and those were applied for determining the hydrolysis and lutetium solubility constants, using the radioactive isotope Lu-177. The first constant of hydrolysis was also determined by the potentiometric method in absence of solidphase. (Author)
Abstract in english A simplified model for drying solids in the constant rate period in a batch fluidised bed was developed.It assumes the bed to be divided into dense and bubble phases with heat and mass transfer between the phases.The model predicts the constant-rate drying period, provided the fluid bed shape and material characteristics are known.The model is compared with experimental data reported in the literature covering a wide range of materials, gas flow rates, column diameters, m (more) aterial hold-ups, air temperatures and humidities.Model predictions compare satisfactorily with the experimental data.
A model of a solid disordered ortho-parahydrogen mixture with infinite long-range interaction J/sub ij/ between orthomolecules distributed in accordance with a normal law with first moment J/sub 0/ is investigated. It is shown that the introduction of an external electric field gradient ..gamma.. can give rise to a phase transition to an orientational phase. The possible existence of an orientational glass phase is established. The influence of the degeneracy of the hydrogen orthomolecules on the low-temperature thermal properties of these systems is demonstrated, and a condition of stability of the replica-symmetric solution is established. At low temperatures, this solution is stable for a large value of ..gamma.. or J/sub 0/.nctio
We investigate the coupling between rock-size solids and gas during the formation of gas giant planets by disk fragmentation in the outer regions of massive disks. In this study, we use three-dimensional radiative hydrodynamic simulations and model solids as a spatial distribution of particles. We assume that half of the total solid fraction is in small grains and half in large solids. The former are perfectly entrained with the gas and set the opacity in the disk, while the latter are allowed to respond to gas drag forces, with the back reaction on the gas taken into account. To explore the maximum effects of gas-solid interactions, we first consider 10 cm size particles. We then compare these results to a simulation with 1 km size particles, which explores the low-drag regime. We show that (1) disk instability planets have the potential to form large cores due to aerodynamic ...
Based on a recently introduced phase X-ray imaging approach, a dual-detector prototype was developed for in-line X-ray phase imaging and phase retrieval utilizing a micro-focus X-ray source and two computed radiography (CR) cassette detectors. The system was built on a horizontal optical rail to facilitate manual adjustment of the positions of the X-ray source, the sample and the detectors. The novel design of the detector-1 is essential, it detects a portion of radiation to form an attenuation image; allows the rest of radiation to reach the detector-2 to form a phase contrast image, and the two images are used to retrieve a phase map. The two detectors are balanced for optimal phase-retrieval with reasonable radiation dose to the object to be imaged. The system was examined in terms of the linearity, the fractions of the X-ray photons detected by the two ...
A mathematical model of a mineral melting cupola furnace for stone wool production has been developed for improving cupola operation. The 1-D, first-engineering-principles model includes mass and heat balances for the gas phase, five solidphases, and four liquid phases. The gas and solid/liquid phases flow countercurrently. Seven chemical reactions account for the conversions of coke, iron oxide, limestone, and gaseous species. The heterogeneous reactions of coke conversion are limited by both kinetics and mass transport. Heat transfer between phases is modeled including both convection and radiation. The model predicts gas concentrations; mass flow rates; and temperature profiles of the solid, melt, and gas in the cupola, as well as heat loss to the water-cooled walls. Inputs to the model include the coke, rock, and ...
This paper describes the comprehensive modeling method of fluid and heat flows in the hydrological system. Based upon the concept that the hydrological system is composed of the air-water 2-phase fluids, and the rock phase, various natural processes are modeled including surface/subsurface 2-phase mass transfer, heat exchanges between fluid phases, between fluid and solidphases, and sensible/latent heat exchanges on the ground surface. A field-oriented numerical simulator is developed, in which a set of governing equations is solved for different variables on the surface and in subsurface regions, respectively. Results of an experimental study are presented, in which transient formulation of heat exchange between fluid/solidphases is examined through matching of the observation and calculated performances. (author)
This paper describes the comprehensive modeling method of fluid and heat flows in the hydrological system. Based upon the concept that the hydrological system is composed of the air-water 2-phase fluids, and the rock phase, various natural processes are modeled including surface/subsurface 2-phase mass transfer, heat exchanges between fluid phases, between fluid and solidphases, and sensible/latent heat exchanges on the ground surface. A field-oriented numerical simulator is developed, in which a set of governing equations is solved for different variables on the surface and in subsurface regions, respectively. Results of an experimental study are presented, in which transient formulation of heat exchange between fluid/solidphases is examined through matching of the observation and calculated performances. (author)
A survey is presented of the principles and practice of tailoring sintering liquid composition and processing cycle to enable crystallisation of intergranular phases in silicon nitride and sialon ceramics. Critical features in sialon ceramics are the O/N balance in residual glasses and post-sintering heat-treatment temperatures to enable nucleation of either intermediate phases at constant composition or oxide phases with re-partitioning of non stoichiometric components in #beta#' or #alpha#' solid solutions. Crystallisation of disilicate phases in non-sialon compositions exemplifies a problem in control of polymorphs with differing atomic volumes. Crystallisation of intergranular phases has an influence mainly on high-temperature mechanical and environmental behaviour of these ceramics. (orig.).
Modeling calculations on the solubility of americium have indicated that basic americium carbonate, and not americium trihydroxide, is the solubility-controlling solid in the pH range from 6 to 10 under the influence of atmospheric CO{sub 2}. The solubility of crystalline {sup 243}AmOHCO{sup 3} has been investigated in batch experiments in near-neutral and basic solutions as a function of dissolution time in 0.1 M NaClO{sup 4} at room temperature under oxic conditions. After the solutions reached steady-state conditions, the influence of dissolved solids on the americium concentration in the supernatant solution was studied by utilizing several experimental methods to separate the solution phase from the solid. The solids were characterized by X-ray powder diffraction analysis.
Solid-state single-photon sources have many desirable features that make them attractive for applications in quantum information processing. However, the phase coherence of such devices can be severely compromised by coupling to the solid-state environment. Here, we study the effects of realistic dephasing environments on a pair of solid-state single photon sources in the context of quantum interference effects such as the Hong-Ou-Mandel dip. By means of exact solutions for the non-Markovian dynamics of the sources, we show that the resulting loss of visibility depends crucially on the timing of photon detection events. Our results demonstrate that the effective visibility can be improved via temporal post-selection, and also that time-resolved interference can be a useful probe of the interaction between the emitter and its host environment.
A dilute tungsten heavy alloy consisting of 50W-35Ni-15Fe (wt pct) was liquid phase sintered at 1,500 C for times ranging from 30 to 960 minutes. This alloy corresponds to a nominal solid content of 20 vol pct at the sintering temperature. Because of the excess liquid, the alloy densified easily and exhibited extensive liquid-solid separation due to the density difference between the phases. The solid content at the compact bottom ranged from 45 to 70 vol pct over position and time. The microstructure of the settled region was quantified for volume fraction of tungsten, grain size, connectivity, and settled solid angle of repose. These results provide a basis for extending the microstructural parameters to possible microgravity conditions. The grain growth rate constant varies with the inverse 2/3 power of the volume fraction of liquid, possibly reflecting ...
A dilute tungsten heavy alloy consisting of 50W-35Ni-15Fe (wt pct) was liquid phase sintered at 1,500 C for times ranging from 30 to 960 minutes. This alloy corresponds to a nominal solid content of 20 vol pct at the sintering temperature. Because of the excess liquid, the alloy densified easily and exhibited extensive liquid-solid separation due to the density difference between the phases. The solid content at the compact bottom ranged from 45 to 70 vol pct over position and time. The microstructure of the settled region was quantified for volume fraction of tungsten, grain size, connectivity, and settled solid angle of repose. These results provide a basis for extending the microstructural parameters to possible microgravity conditions. The grain growth rate constant varies with the inverse 2/3 power of the volume fraction of liquid, possibly reflecting ...
The aim of this study was to assess the influence of the normal menstrual cycle and of menopause on the gastric emptying rate of solids. Gastric emptying was studied in 15 premenopausal and ten postmenopausal women with an isotopic technique after the ingestion of a radiolabelled test meal. Premenopausal women were studied twice: Within 1 week prior to menses and again 1 week after onset of menses. Postmenopausal women were studied only once. The emptying curves of the solid component of the meal fitted a linear model. The half-emptying time was 78[+-]5 min during the follicular phase, 75[+-]7 min during the luteal phase and 76[+-]6 min in postmenopausal women (differences not statistically significant). The mean percentages of the meal retained in the stomach at different time intervals were also similar in the three groups. These results suggest that the menstrual cycle does not influence the gastric ...
The aim of this study was to assess the influence of the normal menstrual cycle and of menopause on the gastric emptying rate of solids. Gastric emptying was studied in 15 premenopausal and ten postmenopausal women with an isotopic technique after the ingestion of a radiolabelled test meal. Premenopausal women were studied twice: Within 1 week prior to menses and again 1 week after onset of menses. Postmenopausal women were studied only once. The emptying curves of the solid component of the meal fitted a linear model. The half-emptying time was 78#+-#5 min during the follicular phase, 75#+-#7 min during the luteal phase and 76#+-#6 min in postmenopausal women (differences not statistically significant). The mean percentages of the meal retained in the stomach at different time intervals were also similar in the three groups. These results suggest that the menstrual cycle does not influence the gastric ...
In this study, a two-stage support-vector-regression optimization model (TSOM) is developed for the planning of municipal solid waste (MSW) management in the urban districts of Beijing, China. It represents a new effort to enhance the analysis accuracy in optimizing the MSW management system through coupling the support-vector-regression (SVR) model with an interval-parameter mixed integer linear programming (IMILP). The developed TSOM can not only predict the city's future waste generation amount, but also reflect dynamic, interactive, and uncertain characteristics of the MSW management system. Four kernel functions such as linear kernel, polynomial kernel, radial basis function, and multi-layer perception kernel are chosen based on three quantitative simulation performance criteria [i.e....
The peculiarities of pulsed laser melting and evaporation of the superconducting ceramics are analyzed by means of numerical simulation. The appearance of the overheated metastable states in solid and liquid phases is shown as a result of the phase front dynamics and volume nature of laser energy release. A method of dynamic adaptation for the multifront Stefan problem is proposed.
This paper presents results of solid-liquid phase change, driven by volumetric energy generation, in a vertical cylinder. We show excellent agreement between a quasi-static, approximate analytical solution valid for Stefan numbers less than one, and a computational model solved using the CFD code FLUENT®. A computational study also shows the effect that the volumetric energy generation has on both the mushy zone thickness and convection in the melt during phase change.
This project, conducted under The United States Department of Energy (DOE) Cooperative Agreement DE-FC36-94GO10002/A002, was part of a multiple-phase effort to develop technologies that improve the energy efficiency and economics of chemical process recovery in the pulp and paper industry. The approach taken was to consider two major alternatives in two phases. Phase I, conducted previously, considered means to improve pulp mill recovery boilers using high-solids advanced combustion of black liquor; while this project, Phase la, considered means to recover kraft pulping mill process chemicals by low-temperature black liquor gasification. The principal steps previously proposed in this program were: (1) Evaluate these two technologies, high-solids advanced combustion and gasification, and then select a path forward using the more promising of these two options ...
Quantitative analytical electron microscopy study of dopant distribution in the microstructure of selected Nd-#alpha#-sialon samples revealed the presence of relatively large amounts of glassy phase at quadruple pockets, which exhibited a common composition similar to a melilite solution. Al segregants were depleted from adjacent grain boundaries to satisfy the 'stoichiometry' of such glass. Existence of this glass results in significant deviation of the Nd-#alpha#-sialon composition from the expected values, which shifts the #alpha#-#beta#-sialon phase boundary. Only extra Nd_2O_3 additives enable a monolithic #alpha#-sialon microstructure. The absence of similar glass in Yb-#alpha#-sialon materials keeps the phase relations from such deviations.
The stability of a couple stress fluid saturated horizontal porous layer heated from below and cooled from above when the fluid and solidphases are not in local thermal equilibrium is investigated. The Darcy model is used for the momentum equation and a two-field model is used for energy equation each representing the solid and fluid phases separately. The linear stability theory is employed to obtain the condition for the onset of convection. The effect of thermal non-equilibrium on the onset of convection is discussed. It is shown that the results of the thermal non-equilibrium Darcy model for the Newtonian fluid case can be recovered in the limit as couple stress parameter C?0. We also present asymptotic analysis for both small and large values of the inter phase heat transfer coefficient H. We found an excellent agreement between the exact solutions and asymptotic solutions ...
A diffusion criterion of the crystal-liquid phase transition (PT) is proposed according to which the PT begins when the E d/ k b ratio reaches a threshold value of E d( s)/ k b T m, where E d is the self-diffusion energy, k B is the Boltzmann constant, T is the absolute temperature, and E d( s) is the self-diffusion energy in the solidphase at the melting temperature T m. It is shown that this criterion is a generalization of the Lindemann criterion and is applicable both to solids exhibiting normal melting and to those melting with a decrease in the specific volume. Based on the new criterion, it is possible to explain the relation T N < T m, where T N, is the crystallization onset temperature. The results of calculations of the T N/ T m ratio well coincide with experimental data.
An apparatus was designed and built for the purpose of exposing samples of solid polymers to varying temperatures, atmospheres and stress levels while quantitatively recording the resulting chemiluminescence. Preliminary data were acquired with this apparatus that show a correlation between an enhanced chemiluminescence signal at a low level of applied stress and a decrease in tensile strength for the most commonly used epoxy resin in high performance fiber composites, TGMDA DDS. The studies with cellular silicone cushions (which are used to accommodate thermal expansion and contraction) have defined the temperature regimes in which accelerated aging tests are valid for extrapolation to ambient temperature. Preliminary data on Kevlar fibers is also discussed.
For the first time, rheological phase method, a simple and effective route, is applied to synthesize novel cathode material LiCoPO{sub 4}. X-ray diffraction spectrometer (XRD), X-ray photoelectron spectrometer (XPS), transmission electron microscope (TEM) and electrochemical impedance spectroscopy (EIS) are taken to investigate this material, respectively. XRD figure shows that the rheological sample is better crystallized than the solid-state one. XPS result of the rheological sample exhibits that the valence of Co is 2+. TEM images show that better dispersed particles with smaller size can be formed by rheological method comparing to the solid-state route. Charge-discharge test is carried out in the range of 3.0-5.0 V at 0.2 mA cm{sup -2}. The initial discharge capacity for rheological phase and solid-state powder is 71.5 and 30.9 mAh g{sup -1}, respectively. The better ...
For the first time, rheological phase method, a simple and effective route, is applied to synthesize novel cathode material LiCoPO4. X-ray diffraction spectrometer (XRD), X-ray photoelectron spectrometer (XPS), transmission electron microscope (TEM) and electrochemical impedance spectroscopy (EIS) are taken to investigate this material, respectively. XRD figure shows that the rheological sample is better crystallized than the solid-state one. XPS result of the rheological sample exhibits that the valence of Co is 2+. TEM images show that better dispersed particles with smaller size can be formed by rheological method comparing to the solid-state route. Charge-discharge test is carried out in the range of 3.0-5.0 V at 0.2 mA cm-2. The initial discharge capacity for rheological phase and solid-state powder is 71.5 and 30.9 mAh g-1, respectively. The better electrochemical property ...
A method is proposed for the quantitative high-temperature isolation of /sup 111/In from silver irradiated by ..cap alpha..-particles into a gas phase containing a mixture of HCl and H/sub 2/O with a total pressure of about 3 Pa for these gases. It is shown that the indium evolved into the gas phase probably occurs in the form of at least three compounds, viz.., the trichloride, monochloride, and oxychloride, which have adsorption temperatures on quartz of around 385, 475, and 655 K, respectively. All these compounds are readily washed from the surface of quartz apparatus by a weak (0.05 M) solution of hydrochloric acid.
We study suspensions of semi-flexible colloidal rods and biopolymers using an Onsager-type second-virial functional for a segmented-chain model. For suspensions of thin and thick fd virus particles we calculate phase diagrams in quantitative agreement with experimental observations, and we find their effective state-point dependent shape to be much shorter and thicker than the actual shape. We also calculate the stretching of worm-like micelles in a host fd virus solution, again finding agreement with experiments. For both systems, our results show that the fd virus stiffness can play a key role in system behavior.
A mathematical and physical model was constructed describing the hydrodynamics of the two-phase mixture in the horizontal steam generator. The HP 9830 A desk-top calculator was used for the computations. The output variable of the solution was the level shape. A quantitative and qualitative comparison was made of the results of computations and experimental data. (author).
IntroductionBreast cancer is the most diagnosed and second leading cause of cancer deaths in the U.S. female population. An estimated 5 to 10 percent of all breast cancers are inherited, caused by mutations in the breast cancer susceptibility genes (BRCA1/2). As many as 90% of all mutations are nonsense mutations, causing a truncated polypeptide product. A popular and low cost method of mutation detection has been the protein truncation test (PTT), where target regions of BRCA1/2 are PCR amplified, transcribed/translated in a cell-free protein synthesis system and analyzed for truncated polypeptides by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and autoradiography. We previously reported a novel High Throughput Solid-Phase PTT (HTS-PTT) based on an enzyme-linked immunosorbent assay (ELISA) format that eliminates the need for radioactivity, SDS-PAGE and subjective interpretation of the results. Here, we report the next generation HTS-PTT ...
Raman and infrared spectroscopy of para-H{sub 2} to pressures in excess of 200GPa and to 8K using new ultrapure synthetic diamond anvils reveals numerous new vibrational excitations in the three high-pressure phases. Highly resolved Raman-active librons indicate differences in orientational ordering between phasesII and III, including evidence for changes within phaseII. The librons in phaseIII are strongly pressure dependent and reflect a substantial increase in ordering with pressure. Multiple vibrons in all three phases (I, II, and III) are observed. The results place new bounds on predicted crystal structures and dynamics of the dense molecular solid. {copyright} {ital 1997} {ital The American Physical Society}
NO{sub x} compounds, specifically NO and NO{sub 2}, are pollutants and potent greenhouse gases. Compact and inexpensive NO{sub x} sensors are necessary in the next generation of diesel (CIDI) automobiles to meet government emission requirements and enable the more rapid introduction of more efficient, higher fuel economy CIDI vehicles. Because the need for a NO{sub x} sensor is recent and the performance requirements are extremely challenging, most are still in the development phase. Currently, there is only one type of NO{sub x} sensor that is sold commercially, and it seems unlikely to meet more stringent future emission requirements. Automotive exhaust sensor development has focused on solid-state electrochemical technology, which has proven to be robust for in-situ operation in harsh, high-temperature environments (e.g., the oxygen stoichiometric sensor). Solid-state sensors typically rely on yttria-stabilized zirconia ...
This paper presents the new thermal hydraulic models describing the hydrodynamics of the solid fuel/steel chunks during an LMFBR hypothetical core-disruptive accident. These models, which account for two-way coupling between the solid and fluid phases, describe the mass, momentum, and energy exchanges which occur when the chunks are present at any axial location. They have been incorporated in LEVITATE, a code for the analysis of fuel and cladding dynamics under Loss-of-Flow (LOF) conditions. Their influence on fuel motion is presented in the context of the L6 TREAT experiment analysis. It is shown that the overall hydrodynamic behavior of the molten fuel and solid-fuel chunks is dependent on both the size of the chunks and the power level. At low and intermediate power levels the fuel motion is more dispersive when small chunks, rather than large ones, are present. At high power levels the situation is ...
The amorphization of a quenched sample of the GaSb-II high-pressure phase was studied at ambient pressure by real-time neutron diffraction in the course of the sample heating from 100 K to room temperature at a rate of 0.4 K min{sup -1}. The transformation to the amorphous state begins at 140 K and is completed near room temperature. The {beta}-Sn type structure was shown to represent only the mean lattice of the high-pressure GaSb-II phase. The superstructure of this phase widely varied with temperature and is caused by the ordered displacement of atoms. The temperature range of the metastable crystalline phase relaxation is divided into three intervals according to the temperature dependence of the tetragonality ratio (c/a). At the boundaries of these temperature intervals, i.e. temperatures T = 170 and 230 K, two second-order phase transitions are observed. Anomalous heat and ...
The amorphization of a quenched sample of the GaSb-II high-pressure phase was studied at ambient pressure by real-time neutron diffraction in the course of the sample heating from 100 K to room temperature at a rate of 0.4 K min-1. The transformation to the amorphous state begins at 140 K and is completed near room temperature. The ?-Sn type structure was shown to represent only the mean lattice of the high-pressure GaSb-II phase. The superstructure of this phase widely varied with temperature and is caused by the ordered displacement of atoms. The temperature range of the metastable crystalline phase relaxation is divided into three intervals according to the temperature dependence of the tetragonality ratio (c/a). At the boundaries of these temperature intervals, i.e. temperatures T = 170 and 230 K, two second-order phase transitions are observed. Anomalous heat and volumetric ...
The characteristics of solidification and melting are reviewed. The properties of water and ice and the phase diagram of water are discussed with special emphasis on ice density. A concise account of the freezing process and the Stefan problem is presented. To this end, the four stages of freezing are identified, supercooling, nucleation and the formation of dendritic ice, the growth of concentric rings of solid ice at 0{sup o}C and the final cooling of the solid ice are treated in some detail. The subject of bursting of pipes is given particular emphasis. Attention is drawn to a common misconception on pipe bursting and to misleading relationships for the computation of freezing time for ice blockage. Several current applications of melting and freezing systems are outlined. (author)
Ab initio lattice dynamics based on linear response method are performed for high pressure phase of yttrium to describe electron-phonon coupling and subsequent superconducting behavior. The critical temperature Tc in fcc-Y increases monotonically with pressure up to 9.25 K at 31 GPa, which is quantitatively in excellent agreement with two quasihydrostatic experiments and is qualitatively compatible with recent experiments. The excellent agreement with experiments gives us a better understanding of the effective pseudopotential ?* as well as spectral function ?2(?)F(?) in yttrium. These results demonstrate that there exists strong electron-phonon coupling in Y within the studied pressure regime, and for lower pressure electron correlation becomes stronger. Generally, it is found that superconductivity in yttrium under pressure can be described quantitatively within standard theory of phonon-mediated superconductivity.
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.
This study compares the microstructure and mechanical properties of plain and 0.9 or 3.6 wt% VC- or Cr{sub 3}C{sub 2}-doped WC-12 wt% Co hardmetals with 40 wt% NbC, prepared by pulsed electric current sintering (PECS) in the solid state for 4 min at 1240 deg. C and conventional pressureless liquid phase sintering (CS) for 1 h at 1420 deg. C. The addition of VC or Cr{sub 3}C{sub 2} was found to inhibit grain growth of the residual WC grains, whereas the size of the solid solution (Nb,W,V/Cr)C grains was hardly influenced. The type of grain growth inhibitor and densification temperature however, strongly influenced the composition of the NbC solid solution formed, which was thermodynamically and experimentally assessed.
This renewal request for DOE grant DE-FG02-86ER45238, is dedicated to providing a complete thermodynamic profile of solids fluids, and fluid mixtures, over a wide range of temperatures and pressures. We are partially motivated by technological interest in detonation, combustion, superhard high pressure materials, and high temperature superconductors, which are important components of interest of various DOE laboratories. Our work on fluids and solids, composed of simple molecules, involves the determination of structures, phase transitions, pressure-volume relations, phonon, vibron, and libron modes of excitation, sound velocities, specific heats, thermal expansion, virial coefficients, sublimation energies, and orientational translational, and magnetic correlations. We hope that the study of these systems under extreme thermodynamic conditions will lead to exotic new materials of value, as well as enhanced fundamental ...
The infrared spectrum of the rotovibrational band {ital v}=0{r_arrow}2 of parahydrogen has been observed in the condensed phases down to {ital T}=2 K. In the solid, phonon and roton sidebands exhibit peaks corresponding to those observed in the fundamental. Contributions arising from the reorientation of ortho-H{sub 2} impurities have been detected. The {ital Q}{sub 1}(0)+{ital S}{sub 1}(0) band has been resolved into an asymmetric doublet, and the origin of this latter is discussed. In the liquid phase the observed line shapes include strong translational contributions, and are accounted for by assuming that at short times the excited molecule is encapsulated in the cage of nearest neighbors.
Consideration is given to the process of the formation of a titanium sponge alloyed with niobium or tantalum, in the joint metallic reduction of titanium, niobium and tantanum chlorides. A percentage composition of the phases observed and the structure of the alloyed sponge have been studied. It is shown that after one remelting operation of the alloyed sponge the alloys of titanium with niobium and tantalum have a uniform component distribution. At the stage of chloride reduction there appear solid solutions based on titanium and an alloying component. The stage of vacuum separation of the reaction mass is associated with a mutual dissolution of the primary phases and the formation of the solid solutions of the alloyed titanium sponge, which, by their composition, are close to the desired alloy composition. The principal features of the formation of a titanium sponge alloyed with niobium and tantalum ...
Twelve powders of TiO_2-Y_2O_3-ZrO_2 solid solution of the methodically changed composition were prepared by a coprecipitation-calcination technique. After mixing with phenol-formaldehyde resin, the powders were calcinated for 2 hours at 1200"oC in vacuum. The resultant composite powders contained TiC and non-reacted carbon. Green compacts were sintered in vacuum at 1500"oC for 2 hours. A temperature increase was stopped at 1200"oC to react remains of carbon. There were two carbides in the composites TiC and ZrC. TiC non-stoichiometry depended on carbon content in the system. Phase composition of the depended on of titania and yttria in zirconia solid solution. The majority of the samples showed two tetragonal zirconia phases differing in lattice parameter and tetragonality. (author)
A radiometric method of measuring the ratio of liquid and solidphases (crust thickness) in a continuous ingot for automation of the continuous steel casting process, has been proposed. The essence of the method is, that radiation flux, bearing information on the object tested, is transformed in a succession of electric pulses, which is processed afterwords for obtaining necessary information. In this case either the flux of non-scattered radiation, passed through the object, or the flux of single-scattered radiation reflected from the object is registered. Block-diagram and specifications of a radiometric device with the Co source of 50 gxequiv. Ra activity developed for this purpose are presented. The technique for calibration ob the device and the results of its tests, are described. It is shown, that introduction of such devices for the control crust thickness at the installations of continuous steel casting of metallurgical works would ...
The influence of headspace solid-phase microextraction (HS-SPME) variables, namely, sample concentration, salt concentration and sample amount, on the equilibrium headspace analysis of the main volatile flavor compounds released from soursop was investigated. A total of 35 volatile compounds, comprising 19 esters, six alcohols, three terpenes, two acids, two aromatics, two ketones and an aldehyde, were identified. The results indicated that all response-surface models were significantly (p<0.05) fitted for 10 target volatile flavor compounds. The results further indicated that more than 65% of the variation in the equilibrium headspace concentrations of target volatile flavor compounds could be explained by the final reduced models, with high R2 values ranging from 0.658 to 0.944. Multiple...
During the recrystallization by solid-phase-epitaxial (SPE) growth of supersaturated silicon alloys, a high concentration of interstitials is trapped. These are released by subsequent heating causing a transient (greatly enhanced) diffusion of the substitutional dopant by an interstitialcy mechanism. The enhancement may be as much as five orders of magnitude over tracer values, and shows an activation energy of only 1.8 +- 0.2 eV. Following the transient, the interstitials condense into loops, allowing an independent estimate to be made of their concentration. From these observations, we propose that during ion implantation, a fraction of the implanted dopants can acquire their natural valency, and retain it as the crystallization interface passes. For group V dopants this creates the trapped interstitials, giving transient enhanced diffusion when they are released by subsequent annealing.
During the recrystallization by solid-phase-expitaxial (SPE) growth of supersaturated silicon alloys, a high concentration of interstitials is trapped. These are released by subsequent heating causing a transient (greatly enhanced) diffusion of the substitutional dopant by an interstitialcy mechanism. The enhancement may be as much as five orders of magnitude over tracer values, and shows an activation energy of only 1.8 +/- 0.2 eV. Following the transient, the interstitials condense into loops, allowing an independent estimate to be made of their concentration. From these observations, it is proposed that during ion implantation, a fraction of the implanted dopants can acquire their natural valency, and retain it as the crystallization interface passes. For group V dopants this creates the trapped interstitials, giving transient enhanced diffusion when they are released by subsequent annealing. 12 references, 6 figures.
In this study, a novel graphene nanosheets (GNSs) coated solidphase microextraction (SPME) fiber was prepared by immobilizing microwave synthesized GNSs on a stainless steel wire. Microwave synthesized GNSs were verified by X-ray diffraction, field emission-scanning electron microscopy (FE-SEM) and transmission electron microscope (TEM). GNS-SPME fiber was characterized using FE-SEM and the results showed the GNS coating was homogeneous, porous, and highly adherent to the surface of the stainless steel fiber. The performance and feasibility of the GNS-SPME fiber was evaluated under one-step microwave assisted (MA) headspace (HS) SPME followed by gas chromatography with electron capture detection for five organochlorine pesticides (OCPs) in aqueous samples. Parameters influencing the extra...
The purpose was to develop a simplified and reliable method of separating free from antibody-bound ligand using a precipitating antibody linked to a cellulose derivative. Dose-response curves and control sera were set up in parallel for various pituitary and placental polypeptides, steroid hormones, insulin, glucagon, triiodothyronine, thyroxine, angiotensin I, calcitonin, gastrin, cyclic AMP, and digoxin. After first-antibody reactions had reached equilibrium, free and bound ligand were separated using a double-antibody solid-phase system in parallel with conventional methods, including dextran-coated charcoal, double-antibody precipitation, single-antibody solidphase, organic solvents, salt precipitation, and anion-exchange resins. The effect of variations in temperature, incubation time, protein content, pH, and amount of separating material added were studied. The results showed that separation was complete within 1 hr ...
The purpose was to develop a simplified and reliable method of separating free from antibody-bound ligand using a precipitating antibody linked to a cellulose derivative. Dose-response curves and control sera were set up in parallel for various pituitary and placental polypeptides, steroid hormones, insulin, glucagon, triiodothyronine, thyroxine, angiotensin I, calcitonin, gastrin, cyclic AMP, and digoxin. After first-antibody reactions had reached equilibrium, free and bound ligand were separated using a double-antibody solid-phase system in parallel with conventional methods, including dextran-coated charcoal, double-antibody precipitation, single-antibody solidphase, organic solvents, salt precipitation, and anion-exchange resins. The effect of variations in temperature, incubation time, protein content, pH, and amount of separating material added were studied. The results showed that separation was complete within 1 hr ...
A number of high voltage cathode materials are now being considered for their ability to increase the energy density of lithium-ion batteries. In this study, a lithium-nickel composite alloy (LiNiVO{sub 4}) was synthesized using a rheological phase reduction method that incorporated mixtures of LiOH-H{sub 2}O, Ni(CH{sub 3}COO){sub 2}, 4H{sub 2}O, NH{sub 4}VO{sub 3} and C{sub 2}H{sub 2}O{sub 4}-2H{sub 2}O. The rheological phase method was used to prepare the compounds from a solid-liquid rheological mixture. Solid reactants were first mixed in a proper molar ratio, and water or solvents were added to the solid-liquid rheological body. X-ray powder diffraction (XRD) and Fourier Transform (FT) analyses were conducted to characterize the powders. Scanning electron microscopy (SEM) was used to characterize the morphological features and particle sizes of the powders. Results of the ...
Aluminum-containing intergranular phases, forming intergranular films and secondary phase particles at triple-junctions in SiC hot-pressed with aluminum, boron, and carbon additions, were studied by transmission electron microscopy. Statistical high-resolution electron microscopy study of intergranular films indicated that a large fraction of the vitreous intergranular films in the s-hot-pressed SiC crystallized during postannealing in argon above 1000 C. However, brief heating to 1900 C indeed re-melted 25 percent of the crystallized intergranular films. The structural transitions were reflected in the statistical width distributions of the amorphous grain boundary layers. At triple-junctions, Al2O3, Al2OC-SiC solid solution, and mullite phases were newly identified. These phases,together with others reported before are represented in a quaternary phase diagram ...
Chemical and phase homogeneity of titanium-niobium sponge, produced by a combined magnesium-thermic reduction of niobium pentachloride and titanium tetrachloride mixtures, is investigated. It is ascertained that a sponge consists of spherical shape particles and has a large number of pores. Particle sizes are reduced with niobium being substituted for titanium from 50-500 #mu#m for titanium sponge to 1-40 #mu#m for niobium one, which testifies to the bormation in a titanium-niobium sponge of an alloy and not a mechanical mixture. A number of solid solutions is detected by X-ray phase analysis. Lattice parameters are determined.
Separation of lithium isotope by NTOE compound was carried out with 0.01M HCl solution. The ion exchange capacity of NTOE was 0.8 meq/g. The separation factor, #alpha#=("7Li/"6Li)_s_o_l_i_d/("7Li/"6Li)_l_i_q_u_i_d was 1.0242 by the elution chromatography. The lighter isotope, "6Li was concentrated in the liquid phase, while the heavior isotope, "7Li was enriched in the solidphase. (author).
The McMaster Neutron Radiography Facility (MNRF) is fortunate to own the only Real-Time Neutron Radiography system in Canada. Current research at the MNRF involves the visualization of gas-liquid and gas-solid two-phase flow in complex channels, such as nuclear fuel channels, using light water, heavy water, freon-134A, slurries, and other fluids. Other research at the MNRF has examined single-phase flow, material purity, film deposition, turbine blades, and automotive parts.
The development status of the EE-1 Small Community Solar Thermal Power Experiment (SCSE Program) is presented. Current activities on the Phase II single module development effort are presented, together with plans for a Phase III 1 MW/sub e/ demonstration plant. A description of the various subsystems and components is given with a brief review of their development background. Latest performance figures are given for a 1 MW/sub e/ plant, based on 56 power modules, each consisting of a 12m parabolic dish concentrator, a cavity receiver, an organic Rankine power conversion subsystem and a ground-mounted solid-state rectifier.
The solubility limit of #alpha#'-SiAlON solid solutions on the Si_3N_4-YN:3AlN composition join in the system Si_3N_4-YN-AlN has been determined at 1800 degrees C. The end members of these solid solutions are Y_0_._4_3Si_1_0_._7Al_1_._3N_1_6 and Y_0_._8Si_9_._6Al_2_._4N_1_6. Unit-cell dimensions of the #alpha#'-SiAlON solid solutions in the system Si,Al,Y/N,O can be expressed as follows: a_0 (Angstrom) = 7.752 + 0.045m + 0.009n, c_0 (Angstrom) = 5.620 + 0.048m + 0.009n, where the #alpha#'-SiAlON solid solution has the formula Y_xSi_1_2_-_(_m _+ _n_)Al_m_+_nN_1_6_-_nO_n. The single-phase boundary of the solid solution #alpha#'-SiAlON on the composition triangle Si_3N_4-YN:3AlN-Al;N:Al_2O_3 is delineated. The present paper also reports the phase relationships involving #alpha#'-SiAlON.
Calculations in "7Li have been carried out for the differential coherent elastic scattering cross-section of thermal neutrons at a fixed scattering angle #theta#_0(148"o) and varying the energy of incident neutrons (or corresponding d-spacings). The results are reported, as variations of the ratio #SIGMA#_0"c"o"h (#theta#_0, d)/#SIGMA#_0"c"o"h (#theta#_0) with d-spacing, at atmospheric pressure and at two temperatures, 80 and 20 K. The calculations at 80 K correspond to BCC lithium whereas at 20 K all the possible crystallographic structures of polytype lithium (BCC, 9R, HCP and FCC) were considered. On comparing our results with the time-of-flight (TOF) measurements of Berliner et al. (Physical Review, B40, 12086, 1989) we find that up to 80 K lithium-7 does not undergo any martenistic transformation whereas the structural state at 20 K can be described by the co-existence of the original BCC phase with 9R, HCP and FCC closed packed structures. A ...
The composite of doped lanthanum gallate (La_0_._9Sr_0_._1Ga_0_._8Mg_0_._2O_2_._8_5, LSGM) and doped ceria (Ce_0_._8Sm_0_._2O_1_._9, CSO) was investigated as an electrolyte for solid oxide fuel cell (SOFC). The LSGM-CSO composite was examined by X-ray diffraction (XRD) and impedance spectroscopy. It was found that the sintered LSGM-CSO composite contains mainly fluorite CeO_2 phase and a minority impurity phase, Sm_3Ga_5O_1_2. The LSGM-CSO composite electrolyte shows a small grain boundary response in the impedance spectroscopy as compared to LSGM and CSO pellets. The composite electrolyte exhibits the highest conductivity in the temperature range of 250-600 "oC, compared to LSGM and CSO. The LSGM-CSO composite can be expected to be an attractive intermediate temperature electrolyte material for solid oxide fuel cells.
The solid state reaction between a Pd thin film and a Si substrate produces a single new phase, Pd/sub 2/Si, for temperatures <700/sup 0/C. When the substrate is a single crystal of (111) surface orientation, this process is particularly interesting because the silicide grows epitaxially. Growth of epitaxial interfacial Pd/sub 2/Si was the focus of this study using X-ray diffraction techniques.
Methods of preparation, stability in solutions and in the solidphase, composition of orthophosphate crystallohydrates and condensed uranyl- and uranium (4) phosphates, are considered. Structures of these compounds are discussed; it is shown that they are steric polymers with an uranylphosphate framework. The problem of phosphate-anion polymerization in the process of thermal decomposition is discussed. It is established that condensed uranyl polyphosphates are not stable during storage, capable of degradation, its degree increasing with the phosphate chain length and uranium content.
Coal solids (SRC) and distillate oils are combined to afford single-phase blends of residual oils which have utility as fuel oils substitutes. The components are combined on the basis of their respective polarities, that is, on the basis of their heteroatom content, to assure complete solubilization of SRC. The resulting composition is a fuel oil blend which retains its stability and homogeneity over the long term.
By means of infrared spectroscopy, x-ray diffraction, and differential thermal analysis, the authors investigate the pyrolysis of dichlorodithiourea cadmium, the vapor phase epitaxy of the cadmium sulfide film, and the composition of the solid and gaseous pyrolysis products. Those products are found to include the thiocyanates of guanidine, ammonium, and hydrogen along with cadmium oxides and sulfates and hydrochloric acid.
In the present study the Pb content in Bi(2223) phase by regression or curve fitting method are optimized. The best fitting curve can be obtained by the method of least square. To study the effect of Pb content in Pb substituted Bi (2223) superconductors, prepared by solid state reaction method data is obtained. The deviation of T_c from the target value for different Pb content is summarized
The kinetics of the reaction of zirconium phosphates with carbon tetrachloride in sodium and potassium chloride melt as well as the effect of temperature, gas flow, solubility and weight of the solidphase of the phosphate, and stirring of the melt on the chlorination rate has been studied. The kinetic parameters of the reaction (rate constants, activation energy, etc.) have been calculated.
A case report of falsely elevated serum hormone values measured by radio-immunoassay (RIA) is described. The radio-immunoassays concerned have a first antibody raised in rabbits and mostly a separation technique based on a second antibody-solidphase system. The presence of heterophyle (anti-rabbit) antibodies in patients' serum is proved.
The refrigerant two-phase flows in a distributor and a simulated plate heat exchanger with a single passage used in a compression-type refrigerator were visualized by real-time neutron radiography. For a distributor, the liquid fraction in the each tube was measured by some image processing method. On the other hand, for a plate heat exchanger, the two-dimensional distribution of void fraction was measured quantitatively by the umbra method. As a result, it was shown that the dynamic behaviors of refrigerant at the inlet of the section strongly affected on the performance, that is, a distribution performance of a distributor and a liquid distribution in a plate heat exchanger. (author)
The report deals with: (1) two-phase flow regime transitions, (2) liquid entrainment in break flow, (3) vapor pull-through, and (4) CCFL in horizontal ducts. The first three processes influence the mass flow through the break, whereas the fourth one imposes a limit on liquid flow from the steam generator through the hot leg break into the core. Correlations available in the literature which deal with these processes are presented and applied to a hot leg of a PWR, LOFT and Semiscale for quantitative estimates, as well as for determining the scale distortion in the latter two facilities.
We discuss how magnetic phenomena affect superconductivity in simple metals, transition metals and alloys thereof, and dilute Rare-Earth alloys. It is shown both qualitatively and quantitatively that superconductors are sensitive probes for studying itinerant spin excitations, local spin excitations associated with nearly magnetic impurities, the effect of the atomic environment on the stability of local magnetic moments, and the nature of the spin order in Rare-Earth alloys. Also, we discuss how magnetic impurities can be used to study the electronic configuration which is responsible for superconductivity in Laves-phase crystals like A-15 compounds and ..beta..-W crystals, for example.
Within the framework of a study on the chemical wear behaviour of sialon ceramics a range of compositions were prepared in which the alumina content was varied from 6 to 77 weight percent. The materials were hot-pressed from alumina and silicon nitride powders to a density of at least 97%. The structure and compositions of the phases occurring in these samples i.e. the O' phase, #beta#'-sialon solid solution and especially the X-phase were thoroughly characterized with respect to structure and composition using electron microprobe and transmission electron microscopy techniques. These results will be discussed in the light of earlier phase diagram studies. Some basic properties such as E-modulus and toughness were measured and related to microstructural features. E-modulus as well as toughness are at a minimum for materials with a high content of the X-phase. ...
A performance assessment of the operating Solid Waste Storage Area 6 (SWSA 6) facility for the disposal of low-level radioactive waste at the Oak Ridge National Laboratory has been prepared to provide the technical basis for demonstrating compliance with the performance objectives of DOE Order 5820.2A, Chapter 111.2 An analysis of the uncertainty incorporated into the assessment was performed which addressed the quantitative uncertainty in the data used by the models, the subjective uncertainty associated with the models used for assessing performance of the disposal facility and site, and the uncertainty in the models used for estimating dose and human exposure. The results of the uncertainty analysis were used to interpret results and to formulate conclusions about the performance assessment. This paper discusses the approach taken in analyzing the uncertainty in the performance assessment and the role of uncertainty in performance ...
Porous flow occurs in a wide range of materials and applies to many commercially relevant applications such as oil recovery, chemical reactors and contaminant transport in soils. Typically, breakthrough and pressure curves of column floods are used in the laboratory characterization of these materials. These characterization methods lack the detail to easily and unambiguously resolve flow mechanisms with similar effects at the core scale that can dominate at the aquifer or oil field scale, as well as the effects of geometry that control the flow at interfaces as in a perforated well or the inlet of an improperly designed column. Non-invasive imaging techniques such as MRI have been shown to provide a far more detailed characterization of the properties of the solid matrix and flow, but usu...
Classical methods for the study of complex fluid phase behavior include static and dynamic equilibrium cells that usually require vapor and liquid recirculation. These are sophisticated, costly apparatus that require highly trained operators, usually months of labor-intensive work per mixture, and the data analysis is also rather complex. Simpler approaches to the fundamental study of azeotropes are highly desirable, even if they provide only selected cuts through the phase diagram. Recently, we introduced an advanced distillation curve measurement method featuring: (1) a composition explicit data channel for each distillate fraction (for both qualitative and quantitative analysis), (2) temperature measurements that are true thermodynamic state points that can be modeled with an equation o...
We present a numerical model of vapor-dominated reservoirs which is based on the well-known conceptual model of White, Muffler, and Truesdell. Computer simulations show that upon heat recharge at the base, a single phase liquid-dominated geothermal reservoir in fractured rock with low matrix permeability will evolve into a two-phase reservoir with B.P.D. (boiling point-for-depth) pressure and temperature profiles. A rather limited discharge event through cracks in the caprock, involving loss of only a few percent of fluids in place, is sufficient to set the system off to evolve a vapor-dominated state. The attributes of this state are discussed, and some features requiring further clarification are identified. 26 refs., 5 figs.
Extraction of rare earths (La, Ce, Pr, Eu, Gd, Er, Yb) from nitrate solutions by melts of carboxylic acids of the C/sub 17/-C/sub 20/ fraction and stearic acid with paraffin, depending on the temperature (60-90 deg), phase contact time and their volume ratio (O:B from 1:5 up to 1:100), pH of the aqueous phase (2-6), rare earth concentration (10/sup -6/-10/sup -3/ m) is studied. It is shown that in the whole concentration range investigated rare earths are extracted quantitatively into the carboxylic acid melt of C/sub 17/-C/sub 20/ fraction at the equilibrium value of pH>=3.8, while into the melt of 0.1 M stearic acid in paraffin at pH>=4.5.
Americium extraction in different oxidation states in two-phase aqueous system based on polyethylene glycol is investigated. Conditions for quantitative extraction of americium (3) and americium (5) from ammonium sulfate solutions within pH=3-5 interval in the presence of arsenazo 3 are found. Composition of the produced americium complexes with reagent is determined; americium (3) interacts with arsenazo 3 in ammonium sulfate solutions with the formation of MeR and Me_2R composition complexes. Absorption spectrum characteristics of americium (3) and- (5) complexes with arsenazo 3 in ammonium sulfate solutions and extracts based polyethylene glycol aqueous solutions are given. Molar extinction coefficients of americium complexes with arsenazo (3) in these solutions are determined.
We present in this article a detailed quantitative discussion of the measurement of the leptonic mixing angle theta_13 through currently scheduled reactor neutrino oscillation experiments. We thus focus on Double Chooz (Phase I & II), Daya Bay (Phase I & II) and RENO experiments. We perform a unified analysis, including systematics, backgrounds and accurate experimental setup in each case. Each identified systematic error and background impact has been assessed on experimental setups following published data when available and extrapolating from Double Chooz acquired knowledge otherwise. After reviewing the experiments, we present a new analysis of their sensitivities to sin^2(2 theta_13) and study the impact of the different systematics based on the pulls approach. Through this generic statistical analysis we discuss the advantages and drawbacks of each experimental setup.
An outline is given of time-dependent wavepacket methods as applied to calculations of molecular collisions with solid surfaces. The methods reviewed include numerical integration algorithms for the time-dependent Schroedinger equation, semiclassical wavepacket treatments, and approximations that treat some of the degrees-of-freedom quantum-mechanically and others classically. The computational and numerical characteristics of these methods are discussed, with emphasis on their particular advantages and relevance in the context of certain molecule/surface scattering problems. For the semiclassical and mixed quantal-classical treatments, the approximation errors and their physical origins are discussed. For the quantum wavepacket techniques a numerical error analysis is presented. The computational efficiency of the various algorithms is considered and examined in the context of several applications. The main focus is on diffractive scattering of atoms and light ...
La{sub 1-x}Sr{sub x}MnO{sub 3} (LSMO) compounds (0.175{<=}x{<=}0.30) were prepared by conventional solid-state reaction method. Temperature dependence of the total hemispherical emittance ({epsilon}{sub H}) of the compounds from 173 to 373 K was measured on a calorimetric emissometer (CE) which was constructed based on the steady-state calorimetric method. The compounds show thermochromic properties and {epsilon}{sub H}'s have low value at low temperature and have high value at high temperature, because the compounds are dominated by metallic phase and insulator phase, respectively. We use the phase separation model to interpret the temperature dependence of {epsilon}{sub H}. (author)
The thermal conductivity of liquid CHCl3, C6H6, and CCl4 is measured by a steady-state method under saturated vapor pressure in the temperature regions corresponding to pre-crystallization temperatures. The experimental results obtained are used to investigate the isobaric thermal conductivity jump ? ?p at the crystal-liquid phase transition in CHCl3, C6H6, and CCl4. The contributions of the phonon-phonon and phonon-rotational interaction to the total thermal resistance in solid and liquid state are specified using a modified method of reduced coordinates. The decrease in the thermal conductivity at the crystal-liquid phase transition, ? ?p, is explained by a combined effect of variations in positional distribution of molecules and in the form of rotational molecular motion.
The thermal conductivity of liquid CHCl3, C6H6, and CCl4 is measured by a steady-state method under saturated vapor pressure in the temperature regions corresponding to pre-crystallization temperatures. The experimental results obtained are used to investigate the isobaric thermal conductivity jump ??p at the crystal-liquid phase transition in CHCl3, C6H6, and CCl4. The contributions of the phonon-phonon and phonon-rotational interaction to the total thermal resistance in solid and liquid state are specified using a modified method of reduced coordinates. The decrease in the thermal conductivity at the crystal-liquid phase transition, ??p, is explained by a combined effect of variations in positional distribution of molecules and in the form of rotational molecular motion.
As a method to make use of a high latent heat of a liquid-solidphase change material in a confined convective heat transfer, a phase change material, lauric acid, was encapsulated in a tiny hollow sphere, and mixed with water, forming a slurry of microencapsulated phase-change material (MCPCM slurry). Four different sizes (200, 100, 50, and 25 {mu}m ID) of MCPCMs were tested in this study. Thermal characteristics of the pure lauric acid and lauric acid MCPCMs were tested by a differential scanning calorimeter. Viscosity of the slurries of water and the capsules was measured by a rotating viscometer. The slurries were also tested in a convective-heat-transfer-test apparatus. (author). 11 refs., 5 figs., 1 tab.
The CERL Code was developed to describe the solution chemistry of the water on the steam generating side of PWR reactors. It is designed to calculate the equilibrium species distribution resulting from the interaction of impurities, corrosion products, and additives in the aqueous solution. It calculates the extent of ion-ion interactions, the precipitation of insoluble species and the amount of solute that partitions into the vapor phase when some of the water evaporates. This knowledge of the bulk phase equilibrium distribution of species, especially the pH should be useful in describing the corrosion processes at the solid liquid boundary. The code does not calculate any changes in oxidation states or any rates of reaction. Therefore, it is incapable of calculating the actual corrosion rates. It is anticipated that it will be used as a subprogram of a larger program that will include the redox reactions and the rates of ...
Although hydrogen is the simplest of atoms, it does not form the simplest of solids or liquids. Quantum effects in these phases are considerable (a consequence of the light proton mass) and they have a demonstrable and often puzzling influence on many physical properties, including spatial order. To date, the structure of dense hydrogen remains experimentally elusive. Recent studies of the melting curve of hydrogen indicate that at high (but experimentally accessible) pressures, compressed hydrogen will adopt a liquid state, even at low temperatures. In reaching this phase, hydrogen is also projected to pass through an insulator-to-metal transition. This raises the possibility of new state of matter: a near ground-state liquid metal, and its ordered states in the quantum domain. Ordered quantum fluids are traditionally categorized as superconductors or superfluids; these respective systems feature dissipationless electrical ...
This research aims at elucidating thermal hydraulic phenomena by carrying out their visualization and measurement which are difficult by conventional method, utilizing the excellent properties of real time neutron radiography and showing the usefulness of neutron radiography. The experiments were carried out on the visualization and measurement of liquid metal flow and mixed phase flow and the visualization and diagnosis of mixed phase flow equipment. As the achievement in this fiscal year, the image-processing method for visualizing quantitatively the distribution of void fraction in gas-liquid two-phase flow has been devised, therefore, its method and results are reported. For the analysis of multi-dimensional two-phase flow, in order to prepare the model and determine the constitution equation, the data on the multi-dimensional distribution of void fraction are required. Void ...
Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. The glass will be produced and poured into stainless steel canisters in the Defense Waste Processing Facility (DWPF). Eventually these canistered waste forms will be sent to a geologic repository for final disposal. In order to assure acceptability by the repository, the Department of Energy has defined requirements which DWPF canistered waste forms must meet. These requirements are the Waste Acceptance Preliminary Specifications (WAPS). The WAPS require DWPF to identify the crystalline phases expected to be present in the final glass product. Knowledge of the thermal history of the borosilicate glass during filling and cooldown of the canister is necessary to determine the amount and type of crystalline phases present in the final glass product. Glass samples of seven projected DWPF compositions were cooled following the ...
The structural parameters of various Haegg phases (H or M_n_+_1AX_n phases) are studied experimentally by x-ray and electron spectroscopies, x-ray diffraction, and ab initio full potential as well as full mutiple scattering theoretical calculations. Experimentally it was found that the structure of all ternary compounds analyzed herein are relaxed. The values of the lattice parameters and relaxations obtained from ab initio calculations are in excellent agreement with those deduced from the analysis of the experimental data. The bonding scheme has been analyzed and the charge transfer between constituting atoms determined. It is demonstrated that the strength and electrical transport properties in these materials are principally governed by the metallic planes. For the solid solution (Ti_0_._5Nb_0_._5)_2AlC, the most salient result is that the basal planes are corrugated, which could explain the solid ...
Chemoheterotrophic thermophilic bacteria were used to achieve enhanced hydrocarbon degradation during slurry-phase treatment of oily waste sludges from petroleum refinery operations. Aerobic and anaerobic bacterial cultures were examined under thermophilic conditions to assess the effects of mode of metabolism on the potential for petroleum hydrocarbon degradation. The study determined that both aerobic and anaerobic thermophilic bacteria are capable of growth on petroleum hydrocarbons. Thermophilic methanogenesis is feasible during the degradation of hydrocarbons when a strict anaerobic condition is achieved in a slurry bioreactor. Aerobic thermophilic bacteria achieved the largest apparent reduction in chemical oxygen demand, freon extractable oil, total and volatile solid,s and polycyclic aromatic hydrocarbons (PAHs) when treating oily waste sludges. The observed shift with time in the molecular weight distribution of hydrocarbon material ...
Chemoheterotrophic thermophilic bacteria were used to achieve enhanced hydrocarbon degradation during slurry-phase treatment of oily waste sludges from petroleum refinery operations. Aerobic and anaerobic bacterial cultures were examined under thermophilic conditions to assess the effects of mode of metabolism on the potential for petroleum hydrocarbon degradation. The study determined that both aerobic and anaerobic thermophilic bacteria are capable of growth on petroleum hydrocarbons. Thermophilic methanogenesis is feasible during the degradation of hydrocarbons when a strict anaerobic condition is achieved in a slurry bioreactor. Aerobic thermophilic bacteria achieved the largest apparent reduction in chemical oxygen demand, freon extractable oil, total and volatile solid,s and polycyclic aromatic hydrocarbons (PAHs) when treating oily waste sludges. The observed shift with time in the molecular weight distribution of hydrocarbon material ...
The stability of a couple stress fluid saturated horizontal porous layer heated from below and cooled from above when the fluid and solidphases are not in local thermal equilibrium is investigated. The Darcy model is used for the momentum equation and a two-field model is used for energy equation each representing the solid and fluid phases separately. The linear stability theory is employed to obtain the condition for the onset of convection. The effect of thermal non-equilibrium on the onset of convection is discussed. It is shown that the results of the thermal non-equilibrium Darcy model for the Newtonian fluid case can be recovered in the limit as couple stress parameter C{yields}0. We also present asymptotic analysis for both small and large values of the inter phase heat transfer coefficient H. We found an excellent agreement between the exact solutions and asymptotic ...
A technique for quantitative determination of cephalothin and desacetylcephalothin in serum using a method based on high-pressure liquid chromatography is described. Both compounds were quantitatively...Full Text Available
Single phase amorphous Al_xHf_1_0_0_-_x alloys with a wide amorphization range (33#<=#x#<=#75) were synthesized by the solid-state interdiffusion of pure polycrystalline Al and Hf powders at room temperature using a rod-milling technique. The mechanisms of metallic glass formation and competing crystallization processes in the mechanically deformed composite powders were investigated by means of X-ray diffraction, differential thermal analysis, scanning electron microscopy and transmission electron microscopy. The numerous intimate layered composite particles of the diffusion couples that formed during the first and intermediate stages of milling (0-173 ks) are intermixed to form amorphous phase(s) upon heating to about 980 K by so-called thermally assisted solid-state amorphization (TASSA). The amorphization heat formation for the binary Al_xHf_1_0_0_-_x system via TASSA, #DELTA#H"T"A"S"S"A_a, ...
The hard-sphere radial distribution functions, g_H_S(r/d,#eta#), for the face-centered cubic and hexagonal close-packed phases have been computed by the Monte Carlo method at nine values of the packing fraction, #eta#[=(#pi#/6)#rho#d"3], ranging from 4% below the melting density to 99% of the close-packed density. The Monte Carlo data are used to improve available analytic expressions for g_H_S(r/d,#eta#). By utilizing the new g_H_S(r/d,#eta#) in the Henderson and Grundke method [J. Chem. Phys. 63, 601 (1975)], we next derive an expression for y_H_S(r/d,#eta#) [=g_H_S(r/d)exp#left brace##beta#V_H_S(r)#right brace#] inside the hard-sphere diameter, d. These expressions are employed in a solid-state perturbation theory [J. Chem. Phys. 84, 4547 (1986)] to compute solid-state and melting properties of the Lennard-Jones and inverse-power potentials. Results are in close agreement with Monte Carlo and lattice-dynamics ...
We present differential scanning calorimetry (DSC), X-ray diffractometry, in situ Moessbauer spectroscopy (MS), and transmission electron microscopy (TEM) studies in Metglas ribbons subjected to different heat treatments. The temperature evolution of the hyperfine field H_h_f(T) and the Curie temperature (T_c) of the amorphous phase are determined. The magnetic field originally present in the amorphous phase has a 'normal' behavior, in the sense that it can be described by the Weiss molecular field theory. The total angular momentum of the iron atoms turns out to be 5/2 and this implies Fe"3"+ in which the electronic spins are uncoupled. When the samples are maintained near T_c (#approx#673 K), three new magnetic phases are detected in the Moessbauer spectra, indicating an onset of a crystallization process well below the first crystallization temperature (T_X_1), as determined by DSC (#approx#820 K). The magnetic behavior ...
The thermal performance and phase change stability of stearic acid as a latent heat energy storage material has been studied experimentally. The thermal performance and heat transfer characteristics of the stearic acid were tested and compared with other studies given in the literature. In the present study, parameters such as transition times, temperature range and propagation of the solid-liquid interface as well as the effect of heat flow rate on the phase change stability of stearic acid as a phase change material (PCM) were studied. The experimental results showed that the melting stability of the PCM is better in the radial direction than in the axial direction. The variation in the melting and solidification parameters of the PCM with the change of inlet water temperature is also studied. We observed that while the heat exchanger tube is in the horizontal position, the PCM has more effective and ...
Stearic acid gel is employed to study the phase evolution of MgTiO{sub 3} nanoparticles by thermal gravimetric analysis, X-ray diffraction, and Fourier transform infrared. During the preparation of stearic acid gel, tetrabutyl titanate easily absorbed moisture to hydrolyze into Ti(OH){sub 4} firstly, and then reacts with stearic acid and magnesium stearate to form magnesium-titanium oxide network polymer gel, meanwhile n-butanol is generated. When stearic acid gel is calcined in air, a series of oxidation and combustion reactions occur, meanwhile apparent heat is given off. The results show that a metastable intermediate phase Mg{sub 2}TiO{sub 4} is generated at 450 {sup o}C and nearly disappeared at 550 {sup o}C. Simultaneously, a new solidphase of MgTiO{sub 3} appears. The metastable intermediate phase Mg{sub 2}TiO{sub 4} is successfully identified in the current work.
The formation of the melilite solid solution phase (M'), Sm_2Si_3_-_xAl_xO_3_+_xN_4_-_x, in an #alpha#-sialon sample of overall composition Sm_0_._6Si_9_._2_8Al_2_._6_9O_1_._3_6N_1_4_._7_6, was studied as a function of time in the temperature interval 1,375--1,525 C. The #alpha#-sialon ceramic contained only minor amounts of the 21R sialon polytype and some residual grain-boundary glass before heat treatment. In situ studies by high-temperature X-ray diffraction were combined with postsintering heat treatment followed by quenching. The M'-phase was found to be formed by two different mechanisms: either crystallization of the residual grain-boundary liquid or a direct decomposition of the #alpha#-sialon phase. The liquid crystallized during the first 10--15 min of heat treatment, yielding a rapid M'-phase formation, and further formation of M'-phase continued at ...
The influence of Pd-Ni substitution on the formation of magnetic phases in the tetragonal U(Ni{sub 1-x}, Pd{sub x}){sub 2}Si{sub 2} system and the concentration magnetic phase diagram are presented. A series of different substitutions was prepared and detailed studies by powder neutron diffraction were performed for x=0.25, 0.5 and 0.75. All compounds order antiferromagnetically and form ferromagnetic basal planes stacked along the c axis (q=(0,0,q{sub z}) propagation). The ground-state phase (AF3) of UNi{sub 2}Si{sub 2} is an uncompensated AF structure (++- stacking (q{sub z}=2/3)). In UPd{sub 2}Si{sub 2} the ground-state phase corresponds to the simple AF structure AF2 (+-+-(q{sub z}=1)). In solid solutions, no traces of the AF3 phase were found for x=0.25 and the ground-state powder patterns correspond to AF2 for x{>=}0.25. (orig.)
The influence of Pd-Ni substitution on the formation of magnetic phases in the tetragonal U(Ni_1_-_x, Pd_x)_2Si_2 system and the concentration magnetic phase diagram are presented. A series of different substitutions was prepared and detailed studies by powder neutron diffraction were performed for x=0.25, 0.5 and 0.75. All compounds order antiferromagnetically and form ferromagnetic basal planes stacked along the c axis (q=(0,0,q_z) propagation). The ground-state phase (AF3) of UNi_2Si_2 is an uncompensated AF structure (++- stacking (q_z=2/3)). In UPd_2Si_2 the ground-state phase corresponds to the simple AF structure AF2 (+-+-(q_z=1)). In solid solutions, no traces of the AF3 phase were found for x=0.25 and the ground-state powder patterns correspond to AF2 for x#>=#0.25. (orig.)
A new method for kinetic experiments with neutrons is described. This method combines the conventional triple-axis neutron spectroscopy with relaxation-type experiments. Whereas the former method yields information about the microscopic dynamics of solids, the latter provides macroscopic relaxation times. The combination of both methods allows to determine the microscopic mechanism of relaxation processes. The time-resolved triple-axis spectroscopy is limited to reversible processes and to time scales from 10"-"3 to 10"4 s. Typical applications are the kinetics of phase transformations (structural and dynamical changes), kinetics of domain distributions, kinetics of (spinodal) decomposition, reversible solid state reactions, time-dependent occupation of phonon states or phonon lifetimes. (orig.).
Gas and plasma nitriding processes were executed in the magnesium with modification by titanium in search for an effective surface treatment method for magnesium alloys. Magnesium-nitrogen system has completely no solid solution or solubility, so that nitride should be only formed by eutectic reaction in the liquid phase. Hence, magnesium is difficult or nearly impossible to have its surface modified by nitriding. Addition of nitride forming element into magnesium enables us to lower the onset temperature of nitriding. Magnesium-titanium alloys with 1 to 5 wt% are yielded by the bulk mechanical alloying and, subjected to gas nitriding for various process conditions. Successful co-formation of Mg{sub 3}N{sub 2} as well as TiN becomes a proof to demonstrate the possibility of gas/plasma nitriding in the solid-state magnesium with aid of nitride former. (orig.)
We present a synchrotron x-ray diffraction study of melting in stacks of two-dimensional crystalline arrays of the membrane protein bacteriorhodopsin. Two distinct regimes have been found as a function of the intermembrane distance d . In the {open_quotes}coupled{close_quotes} regime for d{lt}250 {Angstrom} the temperature (T{sub m}) of the melting transition decreases with increasing d , demonstrating the effect of the repulsive membrane interactions on the intramembrane protein ordering. For d{gt}250 {Angstrom} a {open_quotes}decoupled{close_quotes} regime is found with higher T{sup *}{sub m} independent of d . Below T{sup *}{sub m} a solid-liquid-solid reentrant behavior is observed as d is increased. {copyright} {ital 1999} {ital The American Physical Society}
This paper presents a mathematical model for simultaneous heat and moisture transfer under freezing-thawing in porous hygroscopic material. Even below O{sup o}C, unfrozen liquid water exists in the material which plays an important role in the processes. The model takes into account the existence of unfrozen liquid water. The system is treated as a three-(gas, liquid and solid) phase system of water. Moisture chemical potential is used as a moisture potential. Under freezing, moisture chemical potential is a unique function of local temperature. So, during freezing, two unknown variables to be solved are solid water content and moisture potential or temperature. A simple example of simulation for freezing processes is shown. (author)
A series of [60]fullerene-substituted phenylalanine (Baa) and lysine derivatives have been prepared by the condensation of 1,2-(4prime-oxocyclohexano)fullerene with the appropriately protected (4-amino)phenylalanine and lysine, respectively. Conversion of the imine to the corresponding amine is achieved by di-acid catalyzed hydroboration. The reduction of the imine is not accompanied by hydroboration of the fullerene cage. The [70]fullerene phenylalanine derivative has also been prepared as have the di-amino acid derivatives. The compounds were characterized by MALDI-TOF mass spectrometry, UV/Vis spectroscopy, and cyclic voltammetry. 1H and 13C NMR spectroscopy allowed the observation of diastereomers. Fullerene-substituted peptides may be synthesized on relatively large scale by solid-pha...
The authors discuss several aspects of defect formation in epitax heterostructures based on solid solutions of A"3B"5 semiconductor compounds; these heterstructures were prepared by liquid phase epitaxy by cooling suitable high-temperature solutions from the initial growth temperature. An analysis shows that the regions near heterojunctions are regions of increased defect density even in compositions based on Al /SUB x/ Ga /SUB 1-x/ As-GaAs, Al /SUB x/ Ga /SUB 1-x/ P-GaP, Al /SUB x/ Ga /SUB 1-x/ Sb-GaSb, where the differences in lattice parameters of the contacting materials are a minimum.
Purpose To study the chemical modifications induced upon irradiation of solid human insulin at radiosterilization doses and investigate the influence of the absorbed dose on radiolysis. Materials and Methods Volatile radiolytic products were monitored by gas chromatography coupled with mass spectrometry (GC-MS) and non-volatile products by two different high performance liquid chromatography (HPLC) methods: the formation of higher molecular weight proteins was assessed by size exclusion liquid chromatography whereas assays for related compounds and chemical potency tests were carried out using reverse-phase HPLC-UV. Conformational changes were investigated by measurements of circular dichroism. Results After gamma irradiation at 10?kGy, the recovery of insulin was 96.8%; higher molecular w...
The United States Department of Energy (DOE) at the Morgantown Energy Technology Center (METC) contracted with P.S. Lowell and Co. Inc. (Lowell and Co.) and Jay S. Dweck, Consultant, Inc., (JSD) to enhance the capability of ASPEN in simulating coal gasification and oil shale processing plants. Of particular concern was the capability to predict the distribution of environmentally significant components among the various aqueous and organic liquids and gas streams within or leaving the process. The project was divided into major task areas. The first was to develop and implement the calculational routines necessary for predicting aqueous electrolyte chemical reactions. Part of this effort also was to select a species list and collect and/or regress data for the necessary parameters. The second task was to develop and implement a multi-phase flash capability (including precipitated solids) and unit operations models for a venturi and a ...
Applying an underfeed system, the underfeed circulating spouted bed was designed as a desulfurization reactor. The main objective of the technology is to improve the mixing effect and distribution uniformity of solid particles, and therefore to advance the desulfurization efficiency and calcium utility. In this article, a series of experimental studies were conducted to investigate the fluidization behavior of the solid-gas two-phase flow in the riser. The results show that the technology can distinctly improve the distribution of gas velocity and particle flux on sections compared with the facefeed style. Analysis of pressure fluctuation signals indicates that the operation parameters have significant influence on the flow field in the reaction bed. The existence of injecting flow near the underfeed nozzle has an evident effect on strengthening the particle mixing.
This work was carried out to understand the behavior of the solid and gas phases in a CFB riser. Only the riser is modeled as a straight pipe. A model with linear algebraic approximation to solids viscosity of the form, {musubs} = 5.34{epsisubs}, ({espisubs} is the solids volume fraction) with an appropriate boundary condition at the wall obtained by approximate momentum balance solution at the wall to acount for the solids recirculation is tested against experimental results. The work done was to predict the flow patterns in the CFB risers from available experimental data, including data from a 7.5-cm-ID CFB riser at the Illinois Institute of Technology and data from a 20.0-cm-ID CFB riser at the Particulate Solid Research, Inc., facility. This research aims at modeling the removal of hydrogen sulfide from hot coal gas using zinc oxide as the sorbent in a ...
A new method for the separation and determination of trace amounts of cadmium and zinc in water as their thenoyltrifluoroacetone (TTA) complexes with dibenzo-18-crown-6 (DB18C6) in o-dichlorobenzene has been established by means of synergistic extraction and back-extraction combined with atomic absorption spectrometry. The effect of various factors (synergism with TTA and DB18C6, shaking time, composition of the extracted species, and mutual separation etc.) on the extraction and back-extraction of cadmium and zinc has been in- vestigated. When the mixtures were extracted for 4 min at pH 4.9, only zinc was extracted quantitatively, whereas cadmium remained in the aqueous phase. After the phases were separated, cadmium was again extracted quantitatively at pH 7.5. Then, the two phases were each shaken with 0.05-0.1 mol/l HCl in order to back-extract cadmium and zinc from the organic ...
The complex phase relationships near the BaO-poor region of the quaternary Ba-Sm-Y-Cu-O oxide system prepared in pure air (pO2=22 kPa, 950 oC) and in 0.1% O2 (pO2=100 Pa, 810 oC) have been determined. This investigation also included the subsolidus compatibilities in ten subsystems (Ba-Sm-Y-O, Ba-Sm-Cu-O, Ba-Y-Cu-O, Sm-Y-Cu-O, Ba-Sm-O, Ba-Y-O, Ba-Cu-O, Sm-Y-O, Sm-Cu-O, and Y-Cu-O), and the homogeneity range of five solid solutions (Ba(SmxY2-x)CuO5, (Sm,Y)2O3, (Sm,Y)2CuO4, (Y,Sm)2Cu2O5, and Ba(Sm,Y)2O4). The single phase range of the superconductor solid solution, (Ba2-xSmx)(Sm1-yYy)Cu3O6+z, and the phase compatibilities in its vicinity, which are particularly important for processing, are described in detail. The phase equilibrium data of the Ba-Sm-Y-Cu-O system will enable the improvement of the intrinsic superconducting properties of second-generation wires, ...
The development and evaluation of a post-column reaction detector sensitive to platinum(II) complexes is presented in which sodium bisulfite is used as the derivatizing agent with potassium dichromate as an activating agent. The influences of mobile phase changes (i.e., pH, organic modifiers, electrolytes), oxygen, metal ions, and order of reagent addition on reaction kinetics and product yield are defined and used in optimization of detector response. Detection at lambda/sub max/ 290 nm results in an on-line post-column sensitivity of 40-60 ng/mL for selected cis-dichloroplatinum complexes and a sensitivity of 300-1200 ng/mL for four (substituted)-malonato-platinum complexes. The reaction detector is used to monitor the kinetics of aquation of cisplatin (CDDP) and to quantitate CDDP degradation in plasma. As the sensitivity for CDDP in plasma is comparable to that achieved from high pressure liquid chromatography (HPLC) effluent ...
The feasibility of using three different solid fuels in chemical-looping combustion (CLC) has been investigated using NiO as oxygen carrier. A laboratory fluidized-bed reactor system for solid fuel was used, simulating a chemical-looping combustion system by exposing the sample to alternating reducing and oxidizing conditions. In each reducing phase 0.2g of fuel was added to the reactor containing 20g oxygen carrier. The experiments were performed at 970{sup o}C. Compared to previously published results with other oxygen carriers the reactivity of the used Ni-particles was considerably lower for the high-sulphur fuel and higher for the low-sulphur fuel. Much more unconverted CO was released and the fuel conversion was much slower for high-sulphur fuel such as petroleum coke, suggesting that the nickel-based oxygen carrier was deactivated by the presence of sulphur. The NiO particles also showed good reactivity with methane ...
This thesis enters the field of highly compressed materials equation of state studies. In particular, it focuses on the case of laser shock compressed iron. This work indeed aims at getting to the conditions of the earth's core, comprising a solid inner core and a liquid outer core. The understanding of phenomena governing the core's thermodynamics and the geodynamic process requires the knowledge of iron melting line locus around the solid-liquid interface at 3.3 Mbar. Several experiments were performed to that extent. First, an absolute measurement of iron Hugoniot was obtained. Following is a study of partially released states of iron into a window material: lithium fluoride (LiF). This configuration enables direct access to compressed iron optical properties such as reflectivity and self-emission. Interface velocity measurement is dominated by compressed LiF optical properties and is used as a pressure gauge. Using a dual ...
Besides the multifunctionality, another equally important aspect of nanoparticles is their engineerability to control the geometrical and chemical properties during fabrication. In this work, we exploited this aspect to define asymmetric surface chemistry of an iron oxide nanosphere by controlling the topology of ligand expression on its surface resulting in a particle with two faces, one displaying only amines and the other only thiols. Specifically, amine-functionalized iron oxide nanospheres were attached on a solid support via a crosslinker containing a disulfide bridge. Liberation of the nanosphere using thiolytic cleavage created thiols on the portion of the particle's surface that interacted with the solid support. Employing a solid-phase strategy and a step-by-step addition of particles, the two unique faces on the same nanosphere served as fittings to assemble them into linear nano-chains. Assembly of chains with ...
Nanocrystalline samples of Fe_8_0Mo_2_0 and Fe_5_0Mo_5_0 alloys were prepared by the mechanical milling method. The structure, lattice parameters, and crystallite size were determined by the X-ray diffraction. The magnetic properties of the milled products were determined by the Moessbauer spectroscopy. It was observed that in the case of the Fe_8_0Mo_2_0 alloy a solid solution of Mo in Fe was formed with the lattice parameters of the Fe increasing from 0.28659 nm to 0.29240 nm and the crystallite size decreasing from 250 nm to 20 nm. In the case of the Fe_5_0Mo_5_0 alloy there were no clear changes in values of the lattice parameters of Fe and Mo during the milling process, but the crystallite size decreased from 200 to 15 nm. Moessbauer spectra revealed different magnetic phases in the machanosynthesized Fe_Mo samples. In the case of the Fe_8_0Mo_2_0 alloy, the spectrum for the milled mixture indicated the formation of ...
Research and development has been performed on photochromic materials expected to be used in ultra-high density recording, high resolution indication and photoswitches. With regard to molecular orientation in the ternary system mixed LB film, the result of structural analysis by XPM spectrum revealed that the acceptor constituent in the LB film is so structured that it is separated and laminated with two other constituents, and that the sensitizer constituent and the donor constituent are not recognized of being separated definitely. Regarding the electron movement reaction in the solidphase system, a photo-current measuring experiment was carried out on the laminated film which is vacuum-deposited with the ternary system comprising of the donor, sensitizer, and acceptor. It was concluded that the observed photo-current reflects the electron movement reaction in the solidphase as it is. For the ...
A glass furnace, consisting of a combustion space and a glass melter, uses combustion heat to melt sand and cullet into liquid glass to make products. Glass quality is mainly dependent on the temperature, glass composition, and the level of impurities in a glass melter, which include solid batch/cullet particles, liquid glass, and gas bubbles. A comprehensive computational model using an Eulerian approach has been developed to simulate multiphase flows in a glass melter. It includes all the phases, divides solid particles or gas bubbles into various size groups, and treats each group as a continuum. The derived mass, momentum, and energy conservation equations of the flow are solved for local properties for each phase. The simulation considers the heating and melting of the batch (mainly from the radiative heat from combustion and from the convective heat from the molten glass), the formation and ...
A glass furnace, consisting of a combustion space and a glass melter, uses combustion heat to melt sand and cullet into liquid glass to make products. Glass quality is mainly dependent on the temperature, glass composition, and the level of impurities in a glass melter, which include solid batch/cullet particles, liquid glass, and gas bubbles. A comprehensive computational model using an Eulerian approach has been developed to simulate multiphase flows in a glass melter. It includes all the phases, divides solid particles or gas bubbles into various size groups, and treats each group as a continuum. The derived mass, momentum, and energy conservation equations of the flow are solved for local properties for each phase. The simulation considers the heating and melting of the batch (mainly from the radiative heat from combustion and from the convective heat from the molten glass), the formation and ...
The electrode reaction of Pu{sup 3+}/Pu couple at the interface between LiCl-KCl eutectic melt containing PuCl{sub 3} and liquid Bi phase was investigated by cyclic voltammetry at 723, 773 and 823 K. For comparison, the system was also studied using a solid Mo electrode in place of the liquid Bi electrode. It was found that the electrode reaction of Pu{sup 3+}/Pu couple at the Bi electrode was almost reversible. The redox potentials of Pu{sup 3+}/Pu couple at the liquid Bi electrode in the LiCl-KCl eutectic melt containing 0.87 wt% PuCl{sub 3} (0.0014 mole fraction) at 723, 773 and 823 K were observed to be more positive by 0.575, 0.572 and 0.566 V, respectively, than those at the Mo electrode. These differences in potential were thermodynamically analyzed by assuming a lowering of the activity of Pu in Bi phase according to the alloy formation of PuBi{sub 2}. (author)
A Ni3Al coating was prepared by plasma spraying technique on the surface of titanium alloy. Ni-Al mixed powders, coatings and reaction products were investigated by scanning electron microscope, EDS, DSC and XRD. A tight bonding between the coating and the substrate was formed. The X-ray diffraction analysis of the patterns showed that the coating not only had Ni3Al phase, but also had NiO and Al2O3 phase microcontent. Comparing Ni coated Al to Ni3Al at 900^oC, the diffusion was stronger and the diffusion layer was thicker. A minute pore structure was formed at 1200^oC in the front edge of solid-state reaction layer. So Ni3Al restrained the solid-state reaction of the coating with the substrate, and as a whole weakened the entry of oxygen atoms into the substrate and quenched the out-diffu...
We report on the elimination of defect formation which is associated with high dose indium implantations under solidphase epitaxial regrowth (SPER) annealing conditions of 650-800 deg. C. This is achieved by incorporating a layer of epitaxially grown Si{sub 1-y}C {sub y} layer, strategically located at the end-of-range (EOR) of the implant profile. An indium implant of 115 keV at 1 x 10{sup 14} cm{sup -2} was performed followed by annealing at temperature ranges of 650-800 deg. C. Samples with the Si{sub 1-y}C {sub y} layer revealed the elimination of secondary EOR defects with effectively suppressed indium transient enhanced diffusion (TED), indicating the function of carbon as an efficient sink for silicon interstitials at reduced annealing temperatures, in the SPER dopant activation regime.
The stability of a solid ice cover subjected to rapidly varying water levels and discharge was investigated. The support from the bank limits the stress in the ice cover and consequently bank contact must be maintained to ensure ice cover stability. An analysis was required of the stability of ice hinges, a flexible connection between a solid ice cover and the riverbank. Phase II and phase III of the research involved a field study of the Peace River, investigating the evolution of ice hinges with water level variation, from initial ice cover cracking parallel to the banks, to a fully developed hinge. A test program of midwinter discharge variations was undertaken to gather specific data and measurements of ice hinge link length, ice thickness, hinge joint behavior, riverbank geometry, and response of ice hinging to water level variation. This volume of appendices to the study presents detailed ...
The stability of a solid ice cover subjected to rapidly varying water levels and discharge was investigated. The support from the bank limits the stress in the ice cover and consequently bank contact must be maintained to ensure ice cover stability. An analysis was required of the stability of ice hinges, a flexible connection between a solid ice cover and the riverbank. Phase II and phase III of the research involved a field study of the Peace River, investigating the evolution of ice hinges with water level variation, from initial ice cover cracking parallel to the banks, to a fully developed hinge. A test program of midwinter discharge variations was undertaken to gather specific data and measurements of ice hinge link length, ice thickness, hinge joint behavior, riverbank geometry, and response of ice hinging to water level variation. As a result of the program, concepts developed throughout the ...
In order to model transport of dissolved ions in subsurface environments, one should understand how these ions interact with solidphase adsorbents. Our primary goal has been investigating the reaction mechanisms which affect microcontaminant partitioning between aqueous solutions and solidphase adsorbents, using goethite ({alpha}-FeOOH) as a model adsorbent. Cylindrical internal reflection -- Fourier transform infrared (CIR-FTIR) spectroscopy has been developed as the primary technique for this study. Wet chemical adsorption studies, acoustophoresis and electrophoretic mobility have been used to obtain supporting information as needed. Phenol and o-nitrophenol did not adsorb to goethite. Benzoate, phthalate and p-hydroxybenzoate all adsorbed via a bidentate mechanism to two adjacent iron atoms, while salicylate and 2,4-dihydroxybenzoate formed a chelate complex to single iron atoms. Phosphate ...
Microstructure characterization is important for controlling the quality of laser welding. In the present work, a detailed microstructure characterization by transmission electron microscopy was carried out on the laser welding cast Ni-based superalloy K418 turbo disk and alloy steel 42CrMo shaft and an unambiguous identification of phases in the weldment was accomplished. It was found that there are {gamma}-FeCrNiC austenite solid solution dendrites as the matrix, (Nb, Ti) C type MC carbides, fine and dispersed Ni{sub 3} Al {gamma}' phase as well as Laves particles in the interdendritic region of the seam zone. A brief discussion was given for their existence based on both kinetic and thermodynamic principles.
Microstructure characterization is important for controlling the quality of laser welding. In the present work, a detailed microstructure characterization by transmission electron microscopy was carried out on the laser welding cast Ni-based superalloy K418 turbo disk and alloy steel 42CrMo shaft and an unambiguous identification of phases in the weldment was accomplished. It was found that there are #gamma#-FeCrNiC austenite solid solution dendrites as the matrix, (Nb, Ti) C type MC carbides, fine and dispersed Ni_3 Al #gamma#' phase as well as Laves particles in the interdendritic region of the seam zone. A brief discussion was given for their existence based on both kinetic and thermodynamic principles.
Large quantities of organic chemicals used in reprocessing spent nuclear-fuels at the Hanford Site have accumulated in underground high-level radioactive waste tanks. The organic content of these tanks must he known so that the potential for hazardous reactions between organic components and sodium nitrate/nitrite salts in the waste can he evaluated. The solubilities of organic compounds described in this report will help determine if they are present in the solidphases (salt cake and sludges) as well as the liquid phase (interstitial liquor/supernate) in the tanks. The solubilities of five significant sodium salts of carboxylic acids and aminocarboxylic acids [sodium oxalate, formate, citrate, nitrilotriacetate (NTA) and ethylendiaminetetraacetate (EDTA)] were measured in a simulated supernate solution at 25 degrees C, 30 degrees C, 40 degrees C, and 50 degrees C.
Adding capacity to coal-fired plants in small increments of an overall integrated program may be the solution to the 10-year lead time required for the construction of a new plant. A preliminary study evaluates the technical and economic feasibility of a modular natural gas and coal-fired combined-cycle power plant which can be installed in three distinct phases. The plant sizes are suitable for large industrial and utility applications. The Modular Block Power Plant (MBPP) concept offers the advantages of phase construction, lower capital cost, lower cost electricity, lower air emissions, lower water requirements, and reduced solid waste discharge. Other advantages include part load availability, reduced coal inventory requirements, and easier plant siting. 11 figures, 4 tables.
Odor purification process using bio-function, which is technologically called bio-deodorizing process, utilizes the function of microorganism to convert mal-odor substances to non-odor substances. It attracts attention because the operation cost of a facility is low due to non-use of chemicals and energy, and because it is environmentally friendly without the possibility of generating secondary pollution. It is being used in deodorizing at sewage treatment facilities, fertilizer plants, coating plants, and foundries in Japan, and is more widely used in Europe. The conventional deodorizing technology in Japan mostly focuses on processes of physical chemistry such as activated carbon treatment, chemical scrubbing, combustion, and masking, but bio-deodorizing process tends to replace the conventional processes. This paper explains (1) relation of mal-odor and microorganism, (2) bio-deodorizing system (solidphase system and liquid ...
The percolated or active triple phase boundary (TPB) length per unit volume of Ni-YSZ anode hollow fibers (HFs) containing 60wt.% initial NiO and a spatially varying microstructure were measured using a focused ion beam (FIB)-SEM technique. The measured values of contiguous TPB density were interfaced with a 2-D distributed finite element model of a hollow fiber solid oxide fuel cell. The model was applied to simultaneously solve the ionic and electronic charge balances in the electrodes, which were modelled as overlying continuum materials with effective electronic and ionic conductivities. The model was used to predict the effects of anode microstructure on the distribution of current density, and anode activation polarization. Active TPB lengths of 2.63-8.63 m^-^2 were measured for the ...
Examinations of polished and dry cut sections of feed and tuyere coke revealed some possible mechanisms for the physical influence of mineral compounds on the reactivity and strength of coke. It was observed that rounded particles of mineral phases that are exposed to the pore walls and surface of coke at high temperature create an inorganic cover, thus reducing the surface available for gas-solid reactions. The particles of mineral matter that have a low melting point and viscosity can affect the coke at earlier stages in the blast furnace process, acting in the upper parts of the blast furnace (BF). The temperature-driven redistribution of mineral phases within the coke matrix probably leads to the creation of weak spots and in general to anisotropy in its properties, thus reducing its strength. 9 refs., 2 figs., 1 tab.
The present paper describes the development of a radon standard source for use in establishing the traceability of radon concentration measurements in air. Previously, radon generated by bubbling air through a radium salt solution was widely used for calibration of radon measurement equipment; however, the handling of a solid-phase radon source is easier. In the present study, the radioactivity of radon released in a vapor phase was determined from the difference between the radioactivity of the radium and the residual radon progenies in the source. A germanium detector, calibrated using gamma reference sources, was used for these radioactivity measurements. Under equilibrium conditions the radioactivity of the radon released from the radium source was found to be 988 Bq. The source was sealed in a stainless-steel container having a nominal capacity of 6 l to produce a radon standard source of density of 167.5 [Bq/l].
Phenytoin (PHT), phenobarbital (PHB), lamotrigine (LTG), and topiramate (TPM) are some of the most widely used antiepileptic drugs (AEDs). Monitoring of their concentrations in serum is important for the treatment of epilepsy. A reference measurement procedure (RMP) for certification of PHT, PHB, LTG, and TPM in serum has been developed and critically evaluated. Isotopically labeled compounds of PHT, PHB, LTG, and TPM are used as internal standards for the four AEDs. The four drugs and their respective labeled internal standards are simultaneously extracted from serum using solid-phase extraction prior to reversed-phase liquid chromatography?tandem mass spectrometry (LC-MS/MS). Chromatographic separation was performed using a C18 column. Electrospray ionization (ESI) in the positive ion mo...
Ultraveiolet spectroscopy of molecules in vapour phase gives valuable information about electronic structure of free molecules. But in many cases vaipour phase investigations are not possible and in order to isolate molecules within solid lattice, we used cryogenic temperature and high vacuum technology to study absorption spectrum within the spectral range (230-270)nm of an isolated benzene molecule in Argon, Krpton, Nitrogen, Carbon and methane matrices. The spectra shifts were measured and calculated in the matrix environment for the electronnic transition (B 24--A 19) in benzene molecule using the matrices mentioned above. Molar extinction coefficients and oscillator strength were measured too. (7 tabs., 32 figs., 50 refs.).
Several complex organic molecules are routinely detected in high abundances towards hot cores and hot corinos. For many of them, their paths of formation in space are uncertain, as gas phase reactions alone seem to be insufficient. In this paper, we investigate a possible solid-phase route of formation for methyl formate (HCOOCH3). We use a chemical model updated with recent results from an experiment where simulated grain surfaces were irradiated with 200 keV protons at 16 K, to simulate the effects of cosmic ray irradiation on grain surfaces. We find that this model may be sufficient to reproduce the observed methyl formate in dark clouds, but not that found in hot cores and corinos.
We have studied the dissolution behavior of uraninite, becquerelite, schoepite and uranophane. The information obtained under a variety of experimental conditions has been combined with extensive solidphase characterizations, performed in both leached and unleached samples. The overall objective is to construct a thermodynamic and kinetic model for the long-term oxidation alteration of UO{sub 2}(s), as an analogy of the spent nuclear fuel matrix. We have determined the solubility product for becquerelite (logK{sub s0} 32.7{+-}1.3) and uranophane (logK{sub s0} = 7.8{+-}0.8). In some experiments, the reaction progress has shown initial dissolution of uranophane followed by precipitation of a secondary solidphase, characterized as soddyite. The solubility production for this phase has been determined (logK{sub s0} = 3.0{+-}2.9). We have studied the kinetics of dissolution of ...
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 solidphase, 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
The methods of diffuse-reflection optical spectroscopy and EPR were used to study the state of molybdenum in catalysts prepared by impregnating ultrastable zeolite with molybdenum salt solutions and by mixing in the solidphase with MoCl/sub 5/. It has been shown that molybdenum introduced into zeolites in small amounts is found basically in the form of isolated hexavalent ions of molybdenum. In addition, Mo/sup 5 +/ and Mo/sup 4 +/ ions are also present. Heteropolycompounds also form. The molybdenum ions are most readily reduced in the zeolite prepared by impregnation with a solution of ammonium paramolybdate.
A process is disclosed for the preparation of liquid, storage-stable, polyisocyanate compositions containing a release agent formed in situ which compositions are useful, for example, as binder resins in the formation of particle boards which latter, because of the presence of the release agent, show no tendency to adhere to the face of metal platens used in their formation. The process comprises heating an organic polyisocyanate (polymethylene polyphenyl polyisocyanate preferred) with an acid phosphate (e.g. a mixture of mono-and di-alkyl acid phosphates) under conditions controlled as to time and temperature so as to yield a product which is storage stable and shows no tendency to deposit solid or to separate into two liquid phases.
Transient, greatly enhanced diffusion has been observed on annealing solid-phase-epitaxial (SPE) grown Si-Sb alloys. This is shown to be due to a high concentration of interstitials being trapped during SPE regrowth. The migration enthalpy, for diffusion of Sb by an interstitialcy mechanism was measured as 1.8 +/- 0.2 eV. The interstitials eventually condensed into loops, marking the end of the transient. In a SPE grown Si-Bi alloy a similar transient enhanced diffusion was observed, with an activation energy of 2.0 +/- 0.2 eV, but no loops formed. 8 figures, 7 references.
Transient, greatly enhanced diffusion has been observed on annealing solid-phase-epitaxial (SPE) grown Si-Sb alloys. This is shown to be due to a high concentration of interstitials being trapped during SPE regrowth. The migration enthalpy, for diffusion of Sb by an interstitialcy mechanism was measured as 1.8 +/- 0.2 eV. The interstitials eventually condensed into loops, marking the end of the transient. In a SPE grown Si-Bi alloy a similar transient enhanced diffusion was observed, with an activation energy of 2.0 +/- 0.2 eV, but no loops formed. 8 figures, 7 references.
An investigation of the solidification behavior was carried out on the directionally solidified single crystal superalloy CMSX 6. The relationship between structure morphology and the process parameters has been experimentally determined and illustrated in a solidification diagram. The metallographic analyses of transverse sections within the solidification interval yield the sequence of phase formation and the evolution of solid fraction. The solidification process and the corresponding structure have been discussed in detail. (orig.)
The production of many important commercial materials involves the evolution of a complex fluid through a cooling phase into a hardened product. Textile fibers, high-strength fibers(KEVLAR, VECTRAN), plastics, chopped-fiber compounds, and fiber optical cable are such materials. Industry desires to replace experiments with on-line, real time models of these processes. Solutions to the problems are not just a matter of technology transfer, but require a fundamental description and simulation of the processes. Goals of the project are to develop models that can be used to optimize macroscopic properties of the solid product, to identify sources of undesirable defects, and to seek boundary-temperature and flow-and-material controls to optimize desired properties.
Glow discharge plasma nitriding of AISI 304 austenitic stainless steel has been carried out for different processing time under optimum discharge conditions established by spectroscopic analysis. The treated samples were analysed by X-ray diffraction (XRD) to explore the changes induced in the crystallographic structure. The XRD pattern confirmed the formation of an expanded austenite phase (#gamma#_N) owing to incorporation of nitrogen as an interstitial solid solution in the iron lattice. A Vickers microhardness tester was used to evaluate the surface hardness as a function of indentation depth (#mu#m). The results showed clear evidence of surface changes with substantial increase in surface hardness.
The total and differential atomic pair-correlation functions of an icosahedral (quasicrystalline) solid were determined for the first time, directly by the differential anomalous-x-ray-scattering technique using synchrotron radiation. The observed atomic distances involving uranium atoms in icosahedral Pd/sub 58.8/U/sub 20.6/Si/sub 20.6/ suggest the presence of a quasicrystalline sublattice with vertex decoration. The pair distribution functions in the icosahedral and amorphous phases are similar up to the second-nearest neighbors, or up to 6 A-circle.
The total and differential atomic pair-correlation functions of an icosahedral (quasicrystalline) solid were determined for the first time, directly by the differential anomalous-x-ray-scattering technique using synchrotron radiation. The observed atomic distances involving uranium atoms in icosahedral Pd/sub 58.8/U/sub 20.6/Si/sub 20.6/ suggest the presence of a quasicrystalline sublattice with vertex decoration. The pair distribution functions in the icosahedral and amorphous phases are similar up to the second-nearest neighbors, or up to 6 A-circle.
Full text of publication follows: A porous media solution PORFLO has been developed for the 3-dimensional two-phase flow by describing the process facility in Cartesian or cylindrical coordinates. The local porosity fraction is applied for distinguishing the fluid filled volumes from the solid structures. The solid structure contribute the two-phase flow through the wall friction, flow area and heat transfer. Optionally the solid structure may contain primary liquid of steam generators, steam in the higher temperature and pressure to be condensed or electrical heating power. By using these optional boundary conditions three different process facilities have been analysed. The thermohydraulic solution based on 5-equation approach, where the conservation equations are solved for the liquid and gas (vapour) mass, mixture momentum (giving the velocity only for the mixture), liquid and ...
This report summarizes preliminary 2-D reactive-transport simulations on the injection, storage and transport of supercritical CO{sub 2} in dolostone formations in the Ordos Basin in China. The purpose of the simulations was to evaluate the role that basin heterogeneity, permeability, CO{sub 2} flux, and geochemical reactions between the carbonate geology and the CO{sub 2} equilibrated brines have on the evolution of porosity and permeability in the storage reservoir. The 2-D simulation of CO{sub 2} injection at 10{sup 3} ton/year corresponds to CO{sub 2} injection at a rate of 3 x 10{sup 5} ton/year in a 3-D, low permeable rock. An average permeability of 10 md was used in the simulation and reflects the upper range of permeability reported for the Ordos Basin Majiagou Group. Transport and distribution of CO{sub 2} between in the gas, aqueous, and solidphases were followed during a 10-year injection phase and a 10-year ...
The beta transformation characteristics and mechanical properties of the #beta# titanium alloy Ti_5_0Zr_3_0Nb_1_0Ta_1_0 in the temperature range between 200 and 900 deg. C have been studied by means of X-ray diffraction (XRD), Vickers hardness (HV), and tensile test techniques. In the as-rolled state, only #beta#-phase was identified by XRD. Upon heat-treating at 250 deg. C for 4 h, the #alpha#-phase was precipitated from the #beta#-phase matrix, and leading to an increase of Vickers hardness. A maximum HV value was observed at 400 deg. C, and then HV value decreased with increasing heat-treating temperature. Above 650 deg. C, HV value remained almost constant. During heat-treating at 300-650 deg. C, the decomposition of the metastable #beta#-phase has been found to proceed through a phase separation reaction leading to the formation of #beta#-Ti and #beta#-Zr b.c.c. ...
In-core thermal-hydraulics during a PWR reflood phase following a large-break LOCA are quite unique in comparison with two-phase flow which has been studied widely in previous researches, because the geometry of the flow path is complicated (bundle geometry) and water is at extremely low superficial velocity and almost under stagnant condition. Hence, some phenomena realized during a PWR reflood phase are not understood enough and appropriate analytical models have not been developed, although they are important in a viewpoint of reactor safety evaluation. Therefore, author investigated some phenomena specified as important issues for quantitative prediction, i.e. (1) void fraction in a bundle during a PWR reflood phase, (2) effect of radial core power profile on reflood behavior, (3) effect of combined emergency core coolant injection on reflood behavior, and (4) the core ...
Cultured 3T3-L1 cells have been used as a model system to investigate the mechanism of fatty acid uptake by adipose tissue. Using a 1:1 molar ratio of /sup 14/C-oleate and defatted bovine serum albumin (BSA), fatty acid (FA) uptake was quantitated at 4/sup 0/ and 37/sup 0/ as cell associated radioactivity. The profile of FA uptake in preadipocytes and adipocytes was biphasic; an initial rapid phase (1-20s) followed by a second slower phase (60-480s). At 37/sup 0/ the initial rate of FA accumulation in preadipocytes was identical to that in adipocytes, whereas the rate of accumulation during the second phase increased 7-fold (100 ..mu..M total FA) as a consequence of adipose conversion. When uptake measurements were made at 4/sup 0/ in adipocytes, the initial rate was identical to that at 37/sup 0/, however the rate of second phase decreased 5-fold. Incubation of /sup 14/C-BSA and ...
There are clearly identified scientific requirements for continuous profiling of atmospheric water vapor at the Department of Energy, Atmospheric Radiation Measurement program, Southern Great Plains CART (Cloud and Radiation Testbed) site in northern Oklahoma. Research conducted at several laboratories has demonstrated the suitability of Raman lidar for providing measurements that are an excellent match to those requirements. We have developed and installed a ruggedized Raman lidar system that resides permanently at the CART site, and that is computer automated to eliminate the requirements for operator interaction. In addition to the design goal of profiling water vapor through most of the troposphere during nighttime and through the boundary layer during daytime, the lidar provides quantitative characterizations of aerosols and clouds, including depolarization measurements for particle phase studies.
We report here a many-year study of the qualitative and quantitative content of flavonoids in the reproductive organs of the showy tick trefoil (Desmodium canadense (L.) DC., Fabaceae) - stems, leaves, buds, inflorescences,pods, and seeds - collected at different phases of growth at the Department of Medicinal Plants, Kaunas Botanical Garden, Vytautas Magnus University. HPLC studies identified 15 aglycone and glycoside flavonoids: apigenin, apigenin-7-O-glycoside, luteolin, rutin, vicenin-2, vitexin, isovitexin, vitexin rhamnoside, orientin, homoorientin, quercetrin, quercetin, hyperoside, astralagin, and kaempferol. The largest quantities of flavonoids in the vegetative organs from year 2 to year 4 of plant growth were present in the leaves (2.64% and 2.61% at budding and flowering in the...
New RNAA determinations of Ba, Sr, Zr, U, Re, Pd, Ag, Zn and Se and INAA measurements of Lu are added to published data for 21 other elements in the same suite of ten samples. On the average, 21 refractory elements are not significantly fractionated from one another. The mean of their enrichment factors relative to C1 chondrites is 17.5 +- 0.4, indicating that the high-temperature condensate inclusions represent 5.7 wt% of the total condensable matter. Os, Ir, Ru, Re and most of the W condensed in one or more refractory siderophile element alloys along with small fractions of the Pd, Co, Au and Ag. The bulk of the Eu and Sr condensed in solid solution in melilite. Sc, Zr, Hf, Ta, U and the remaining REE condensed in a phase whose abundance in the inclusions in negatively correlated with that of melilite, either diopside or one or more minor or trace phases, including perovskite. Ba condensed in a different ...
The n=4 Aurivillius phase, Bi5Ti3CrO15, was synthesised by solid state reaction. Rietveld analysis of high resolution neutron diffraction data demonstrated this material to adopt the polar space group A21am at room temperature, transforming to the aristotype I4/mmm structure above 650 oC. This phase transition is coincident with an anomaly in DSC signal and relative permittivity, which are characteristic of a ferroelectric-paraelectric phase transition. Bi5Ti3CrO15 exhibits paramagnetic behaviour at low temperature, with short range antiferromagnetic interactions, but no evidence for long range magnetic ordering. This is considered a consequence of significant disorder of Ti and Cr over the available octahedral sites, as demonstrated by analysis of neutron diffraction data. -- Graphical abstract: We report here the synthesis, structure and characterisation of the n=4 Aurivillius ...
Quantitative bone scintigraphy was performed in patients with prostatic carcinoma before orchiectomy as well as two weeks, two and six months after operation. The count rate was recorded as serial gamma camera images over the lower thoracic and all lumbar vertebrae from 1 to 240 min and at 24 h after injection of "9"9"Tc"m-MDP. In almost all abnormal vertebrae an increased count rate was observed within one hour after injection. Most of the vertebrae which were considered normal at 4 h after injection, but had an increased 24h/4h ratio developed into abnormal vertebrae later in the study. The patients with normal bone scintigrams showed no change in "9"9Tc"m-MDP uptake during the study. The reproducibility of quantitative bone scintigraphy was found to be #+-# 7% (1 SD). In response to therapy, most of the patients with abnormal bone scintigrams showed an increase in count rate two weeks after operation followed by a decrease to the ...
Three phosphate based ceramics were studied for the immobilization of tri- and tetravalent actinides: britholites Ca{sub 9}Nd{sub 1-x}An{sub x} {sup IV}(PO{sub 4}){sub 5-x}(SiO{sub 4}){sub 1+x}F{sub 2}, monazites/brabantites Ln{sub 1-2x}{sup III}Ca{sub x}An{sub x}{sup IV}PO{sub 4} and Thorium Phosphate Diphosphate (TPD) Th{sub 4-x}An{sub x}{sup IV}(PO{sub 4}){sub 4}P{sub 2}O{sub 7}. For each material, the incorporation of Th, U(IV), or Ce(IV) in the structure was examined. This work was the early beginning of the incorporation of {sup 239}Pu and/or {sup 238}Pu in order to evaluate the effects of {alpha} -decay on these three crystallographic structures. The syntheses were carried out using dry chemistry methods, involving mechanical grinding then heating treatment (1100 deg C {<=} {theta} {<=} 1400 deg C). For britholites, we showed that the incorporation of thorium was complete for weight loading lower than 20 wt.% through the (Nd{sup 3+}, PO{sub 4}{sup 3-}) ...
The commercial solidphase microextraction (SPME) fibers are not stable enough in organic solvent and tend to swell and strip off from the silica fiber in the high performance liquid chromatography (HPLC) mobile phase, and therefore the application of SPME coupled online with HPLC is limited. In this study, an SPME fiber coated with single walled carbon nanotubes (SWCNTs), prepared by means of electrophoretic deposition, was coupled on line to HPLC for the determination of four endocrine-disrupting compounds, i.e. bisphenol A (BPA), estrone (E(1)), 17?-ethynylestradiol (EE(2)) and octylphenol (OP), in aqueous samples. The results showed that the SWCNTs coating on the prepared fiber did not swell and strip off from the platinum fiber throughout the experiment, thus indicating a high resistance to the HPLC mobile phase, the mixture of water and acetonitrile. The SWCNTs fiber had similar (for OP) or higher ...
Pretreatment of brown coal in oil was conducted using 1-methyl naphthalene or mixture of tetralin and 1-methyl naphthalene as solvent at temperatures ranging from 300 to 430{degree}C under nitrogen atmosphere. Effects of the solvent properties on the structural change of oxygen-functional groups (OFG) and coal liquefaction were investigated by means of quantitative analysis of OFG and solid state {sup 13}C-NMR measurement. When hydrogen transfer from solvent was insufficient, it was suggested that brown coal molecules loose their hydrogen to be aromatized. While, at lower temperatures ranging from 300 to 350{degree}C, hydrogen contained in brown coal molecules was consumed for the stabilization of pyrolytic radicals, and the deterioration of liquefaction was not observed. When hydrogen transfer from solvent was insufficient at higher temperatures above 400{degree}C in nitrogen atmosphere during pretreatment in oil, crosslinking like benzofuran ...
A rapid and sensitive method for the separation and determination of titanium and iron in thiocyanate system has been developed. The extractability of Ti(II) by high molecular weight (HMWA) in organic solvent (HCl/sub 3/) and its separation from Fe(III) was examined. The yellow coloured complex of Ti(II)-SCN in quantitatively extracted into the organic phase containing tribenzyl tribenzylamine (TBA) - a high molecular weight amine, whereas the blood red coloured complex of Fe(III)-SCN formed under the same conditions get separated in the aqueous phase. On the basis of the selective extractability, a method has been developed for the separation as well as simultaneous determination of Ti(II) and Fe(III) in presence of many other elements. The molar extinction coefficients were found to be 1.9 x 10/sup 5/ l mol/sup -1/ cm/sup -1/ and 1.11 x 10/sup 5/ l mol/sup -1/ cm/sup -1/ respectively for Ti(II) and Fe(III). The ...
The Four years of the IMPACT, 'Integrated Modular Plant Analysis and Computing Technology', project Phase 1 have been completed. The verification study of Severe Accident Analysis Code SAMPSON prototype developed in Phase 1 was conducted in two steps. First, each analysis module was run independently and analysis results were compared and verified against separate-effect test data with good results. Second, with the Simulation Supervisory System, up to 11 analysis modules were executed concurrently in the parallel environment (currently, NUPEC uses IBM-SP2 with 72 process elements), to demonstrate the code capability and integrity. The target plant was Surry as a typical PWR and the initiation events were a 10-inch cold leg failure. The analysis is divided to two cases; one is in-vessel retention analysis when the gap cooling is effective (In-vessel scenario test), the other is analysis of phenomena event is extended to ex-vessel due to the ...
In the present paper, the chemical composition of passive films formed on both phases of two types of duplex stainless steels (UNS S31803 and UNS S32304) is determined at the micro-scale using Auger electron spectroscopy (AES). Samples were either mechanically polished (down to diamond pastes) or electrochemically etched in acidic solutions. The micro-electrochemical behavior of samples was then determined in sodium chloride media by means of the electrochemical micro-cell technique (capillary diameters of 30 {mu}m). The results obtained were analyzed considering the passive film chemical composition. Quantitative relationships between electrochemical parameters and the distribution of chromium and iron in the oxide layer were found. Due to differences in mechanical properties between ferrite and austenite, a heterogeneous stress distribution is generated in both phases. A method based on thermal-mechanical simulation was ...
In the present paper, the chemical composition of passive films formed on both phases of two types of duplex stainless steels (UNS S31803 and UNS S32304) is determined at the micro-scale using Auger electron spectroscopy (AES). Samples were either mechanically polished (down to diamond pastes) or electrochemically etched in acidic solutions. The micro-electrochemical behavior of samples was then determined in sodium chloride media by means of the electrochemical micro-cell technique (capillary diameters of 30 ?m). The results obtained were analyzed considering the passive film chemical composition. Quantitative relationships between electrochemical parameters and the distribution of chromium and iron in the oxide layer were found. Due to differences in mechanical properties between ferrite and austenite, a heterogeneous stress distribution is generated in both phases. A method based on thermal-mechanical simulation was used ...
A method of grafting lignin-containing materials is now known which allows 1-phenylethylene or 4-methyl-2-oxy-3-oxopent-4-ene graft copolymers of wood to be quantitatively made. Graft copolymer is formed by conducting a free-radical polymerization with 1-phenylethene in nitrogen-saturated, organic or aqueous/organic solvent containing a lignin source, calcium chloride, and a hydroperoxide. Grafting changes solubility and surface properties of the wood. The lignin-containing materials grafted are unbleached wood pulps produced by chemical, thermal, and mechanical pulping. Grafting wood pulp produces a wood-reinforced, thermoplastic composite. When a particular plastic is to be blended with wood, we react the wood with the monomer used to make that plastic. This creates a hydrophobic surface of the plastic on the wood. This plastic coating can readily bond to the continuous plastic phase. The products of this grafting reaction are thermoplastic ...
Chemical phase identifications of complex, multilayered corrosion products formed on Fe-Ni-Cr alloys immersed in molten NaNO/sub 3/-KNO/sub 3/ and LiNO/sub 3/-NaNO/sub 3/-KNO/sub 3/ were obtained by X-ray diffraction analysis. Diffraction analyses performed after successive material removal steps provided depth profiles of corrosion products and identified the dominant phases as NaFeO/sub 2/, Fe/sub 3/O/sub 4/, and Cr/sub 2/O/sub 3/ for Alloy 800 and 316SS after immersion in NaNO/sub 3/-KNO/sub 3/. In LiNO/sub 3/-NaNO/sub 3/-KNO/sub 3/, the major corrosion products identified on Alloy 800 were LiFeO/sub 2/, Fe/sub 3/O/sub 4/, and Cr/sub 2/O/sub 3/. X-ray diffraction results were supplemented by electron microprobe analyses that revealed the solid solution nature of several of the oxide phases.
This report summarizes the work on high field superconducting materials and processes performed at the Materials and Molecular Research Division of the Lawrence Berkeley Laboratory. Two major interrelated focal points characterize this research. One was the decision to restrict the effort to A-15 compounds because of their superior critical temperatures and critical fields. The inherent brittleness of these compounds along with the requirement for a filamentary morphology led to the second focal point: a heavy reliance on a powder approach for the fabrication of superconducting tapes and wires. There have been exceptions to the use of powder techniques where special circumstances such as the nature of a particular alloy system suggested on alternative approach. The quench-age technique described herein is an example of a non-powder approach. Here the niobium-aluminum system is involved and the methodology is based on the fact that in a certain composition range a ...
Summary Purpose BMS-275183 is an oral C-4 methyl carbonate analogue of paclitaxel that has the same mechanism of action, stabilization of tubulin polymerization. The present study was designed to: (i) assess the safety and tolerability of BMS-275183, and (ii) determine a suitable Phase II dose of BMS-275183 when given on a continuous daily schedule to patients with advanced solid tumor(s). Methods This was a multi-institutional, open-label, Phase I, single-arm dose escalation study in which cohorts of eligible patients with advanced malignancies were treated with BMS-275183 orally on a continuous daily schedule. The starting dose level was 6?mg/m2/day administered once daily. Cohorts of 3 patients were treated at each dose level provided no dose-limiting toxicities (DLTs) were observed. Ea...
Several heat transfer augmentation mechanisms contribute to the heat transfer augmentation around the stagnation point in the gas-solid two-phase impinging jet flow. Among those contributions, that of heat exchange was numerically analyzed and characteristically elucidated by the unsteady direct contact heat conduction at the time of impingement between the laden particles and heat transfer surface. In other words, if the contact time is short between the particles and heat transfer surface, the former is heated by heat stored in the latter as a heat capacity. In such a region, the heat quantity to be transferred to the particles changes by not only the thermal property value (heat capacity multiplied by heat conduction coefficient) of particles but also that of heat transfer surface. Then by using several kinds of particles and heat transfer surface, different in thermal property value, experimental measurement was planned of heat transfer ...
The generation of industrial solid wastes containing leachable species of environmental concern is a problem for developing and developed nations alike. These materials arise from direct processing of mineral ores, from production of metals and minerals, from manufacturing operations, and from air and water pollution treatment processes. The general characteristics that make these wastes intractable is that their content of hazardous species is not easily liberated from the waste yet is not bound so tightly that they are safe for landfill disposal or industrial use. The approach taken in this work is a thermal treatment that separates the inorganic contaminants from the wastes. The objective is to provide recovery and reuse of both the residual solids and liberated contaminants. The results from operating this technique using two very different types of waste are described. The reasons that the process will work for a wide variety of wastes are ...
The object and the purpose of the present work was to develop, to assemble and to start running a new TOF (time of flight) mass spectrometer for imaging SNMS analytic which is optimized for the analysis of highly molecular secondary ions. The most important purpose was the characterization of the TOF mass spectrometer. The obtained mass spectra of indium, tantalum and silver clusters reflect the excellent properties of the TOF mass spectrometer for the detection of large clusters with good detection efficiency up to masses of 16000 amu. The possibility of the deflection of selected saturated atom and cluster peaks serves for further improvement of the detection efficiency for large molecules. The accessible mass resolution was determined to be of the order of m/{delta}m=1000 in the high mass region. Numerous measurements were carried out to characterize the useful yield of this spectrometer. For a best possible adaptation of the TOF mass spectrometer for the detection of highly ...
The retention indices of cycloalkenes and cycloalkadienes with C/sub 6/-C/sub 13/ rings are determined by gas-liquid chromatography (GLC) on glass capillary columns coated with OV-1 and Ucon LB 550X and by gas-solid chromatrography (GSC) on a microcolumn packed with uncoated graphitized thermal carbon black (GTCB). Structure-retention correlations are derived on using index differences such as H/sup OV/, H/sup GTCB/ and ..delta..I values, considering the differences in the stereochemistry of these compounds. It is shown that the combined application of index increments obtained in GLC and GSC provides more detaled structure informations. The value of the retention index units agree with the most stable conformations of the alicyclic compounds. The high value for the energy equivalent to an index unit (..delta..G/sub I.U./ = 4.18 kJ/mol) confirms that graphitized thermal carbon black causes much stronger dispersive interactions than any nonpolar liquid ...
We discuss the possibility of extending solid state laser technology to high average power and of improving the efficiency of such lasers sufficiently to make them reasonable candidates for a number of demanding applications. A variety of new design concepts, materials, and techniques have emerged over the past decade that, collectively, suggest that the traditional technical limitations on power (a few hundred watts or less) and efficiency (less than 1%) can be removed. The core idea is configuring the laser medium in relatively thin, large-area plates, rather than using the traditional low-aspect-ratio rods or blocks. This presents a large surface area for cooling, and assures that deposited heat is relatively close to a cooled surface. It also minimizes the laser volume distorted by edge effects. The feasibility of such configurations is supported by recent developments in materials, fabrication processes, and optical pumps. Two types of lasers can, in ...
Abstract Lithium-indium oxide is one of the candidate materials as solid-state scintillators for solar neutrinos due to an inverse --decay of 115In to 115Sn. On the other hand, when doped with rare-earth ions such as Eu3+ or Sm3+, it becomes a promising phosphor material. In this report we present a simple solid-state procedure for preparation of LiInO2:Eu3+ powders. X-ray diffraction confirmed prod-uct in tetragonal structural form (space group: I41/amd) and no impurity phases were detected. Then, high resolution photoluminescence emission measurements were performed at room and low temperatures to find 5D0 - 7FJ. Emission kinetics from 5D0 level exhibited pure single exponential behavior with lifetime of about 1.5 ms. Maximum energy splitting of 7F1 manifold is recorded as a function of ...
Useful bipolar transistor action over the full temperature range from 78 to 823K has been demonstrated for mesa-isolated, liquid-phase epitaxial n/sup +/npn, GaP/Al/sub 0/ /sub 35/Ga/sub 0/ /sub 65/P/GaP/GaP structures. This represents both the highest temperature and the widest temperature range (745K) over which useful solid-state transistor action has ever been demonstrated in any III-V compound semiconductor system. These results imply that the GaP/Al/sub x/Ga/sub 1-x/P chemical system is an excellent materials candidate in which to base a technology for high-temperature electronics and the results also imply the very real possibility of functional solid-state devices and circuits at temperatures in excess of 500/sup 0/C.
The relationship between processing, microstructure, and properties was studied for A-15 compounds in multifilamentary composites produced by solid-state diffusion and in thin-film samples produced by vapor deposition. Grain sizes of A-15 superconducting compounds were measured by transmission electron microscopy of multifilamentary composites reacted at various temperatures. Critical current densities at 4.2 K and fields up to 6 T were found to be similar for niobium-tin, vanadium-gallium, and vanadium-silicon of the same grain size. Study of the Cu-V-Si phase diagram led to the production of improved multifilamentary vanadium-silicon conductors. The effects of various alloying elements on A-15 layers produced by solid-state diffusion were studied. The most promising new observation was that tantalum can be incorporated into niobium-tin reaction layers, leading to an enhancement of critical currents at high fields. The ...
Ceramic matrix composites in the TiC-Ti, Y-TZP system can be synthesized by the reaction between carbon and the TiO_2-Y_2O_3-ZrO_2 solid solution nanopowder. This method results in the more homogeneous powders than those prepared by the physical mixing of TiC and zirconia s.s. powders. Twelve TiO_2-Y_2O_3-ZrO_2 solid solution nanopowders differing in the proportions of the constituent oxides were prepared by the coprecipitation- calcination route. They were reacted with the pyrolytic carbon evenly distributed within the system. Carbon was introduced by the thermal decomposition of the phenol-formaldehyde resin dissolved in ethyl alcohol and mixed with the zirconia s.s. nanopowder. Reaction was performed in vacuum. Compacts of the composite powders sintered in vacuum give dense materials of evenly distributed TiC inclusions of sizes not surpassing 400 nm. Hardness of such materials was dependent on their chemical and phase ...
The aim of this study was to search for a sorbent that could act as an extraction phase and as a support for solid-matrix time-resolved luminescence (SMTRL). Four potential sorbents were investigated for this purpose using tetracycline (TC) as a model analyte. Sorbents prepared from C18 silica gel or calcium cross-linked pectin gel were able to extract TC from dilute solutions. Europium(III)-TC complex adsorbed on the surface of C18 generated the most intense TRL signal when measured at {lambda}{sub ex} = 388 nm and {lambda}{sub em} = 615 nm. This method achieved a 1 ng/ml limit of detection (LOD) with a 100 {mu}l sample solution in a repeated spotting mode. Hyphenation of sorbent extraction and SMTRL was demonstrated using C18. This method is suitable for screening of TC in foods or aqueous solutions and can be extended to other luminescent lanthanide-chelating analytes in physiological or environmental samples.
A new two-step solid-state process was developed for synthesis of a pure phase 4.7 V LiMn{sub 1.5}Ni{sub 0.5}O{sub 4-{delta}} (LMNO) spinel of good electrochemical properties. This process which was based on formation of stable Ni{sub 1-x}Mn{sub 2}O{sub 4-{delta}} (x {<=} 0.33) spinel followed by subsequent lithiation, demonstrated the emerging of LiMn{sub 1.5}Ni{sub 0.5}O{sub 4-{delta}} frame work at temperatures of as low as 350 C. During this lithiation process, migration of metal ions (Ni/Mn) from partially occupied tetrahedral 8a sites (in Ni{sub 0.67}Mn{sub 2}O{sub 4-{delta}}) toward octahedral 16d site occurred. The resultant spinel material displayed low irreversible loss, a 97% columbic efficiency and 6% loss in discharge capacity after 100 cycles at 60 C. (author)
A three-dimensional, three-phase, multiple-component numerical simulator was developed to investigate transport and growth of microorganisms in porous media and the impacts of microbial activities on oil recovery. The microbial activities modeled in this study included: (1) growth, retention, chemotaxis, and end product inhibition of growth, (2) the formation of metabolic products, and (3) the consumption of nutrients. Major mechanisms for microbial enhanced oil recovery (MEOR) processes were modeled as follows: (1) improvement in sweep efficiency of a displacement process due to in situ plugging of highly-permeable production zones by cell mass or due to improved mobility control achieved by increasing the viscosity of the displacing fluid with a biopolymer, and (2) solubilization and mobilization of residual oil in porous media due to the reduction of the interfacial tension between oleic and aqueous phases by the production of a ...
The evaluation of biological markers is recognized as necessary to the future of toxicology, epidemiology, and quantitative risk assessment. For biological markers to become widely accepted, their validity...Full Text Available
Quantitative microscopy has been extensively used in biomedical research and has provided significant insights into structure and dynamics at the cell and tissue level. The entire procedure...Full Text Available
LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} was prepared through a solid-state reaction using various Ni precursors. The effect of precursors on the electrochemical performance of LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} was investigated. LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} made from Ni(NO{sub 3}){sub 2}.6H{sub 2}O shows the best charge-discharge performance. The reversible capacity of LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} is about 145 mAh g{sup -1} and remained 143 mAh g{sup -1} after 10 cycles at 3.0-5.0 V. The XRD results showed that the precursors and the dispersion methods had significant effect on their phase purity. Pure spinel phase can be obtained with high energy ball-milling method and Ni(NO{sub 3}){sub 2}.6H{sub 2}O as precursor. Trace amount of NiO and Li{sub 2}MnO{sub 3} phase were detected in LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} with manual-mixture method and using Ni(CH{sub 3}COO){sub 2}.6H{sub 2}O, NiO and Ni{sub ...
Magnetothermal measurements up to 1600 K have been made on alloys in the ternary Ni-Mn-Sb system with a constant ratio Mn/Sb=1/1, to which belong the two ferromagnetic Heusler phases Ni/sub 2/MnSb with L2/sub 1/ structure and NiMnSb with C1/sub b/ structure. The susceptibility-temperature curves show the constitution of the vertical section. At high temperatures the susceptibilities obey a Curie-Weiss law. In the solid state the effective magneton number decreases with increasing Mn concentration from 4.9 (Ni/sub 2/MnSb) to 3.8 (NiMnSb). Simultaneously, on the transition from Ni/sub 2/MnSb to NiMnSb there is a strong increase of the susceptibility and of the Curie temperature from 292 to 686 K. In the heterogeneous range between 10 and 20 at.% Mn another phase part appears which is ferromagnetic at room temperature. By a heat treatment it undergoes a distinct development. In the liquid phase, the alloys ...
The helium-cooled HTGR (High Temperature Gas-cooled Reactor) will take an important position in the global energy strategy. It is expected to supply not only electricity but also high quality thermal energy for various industries and local utilities without exhausting any green house effect gas or acid rain gas. The key R and D issue of the HTGR is economical competitiveness, particularly against light water reactors. Due to the poor heat transfer of the single phase helium, the HTGR's volumetric power density is restricted to tenth of corresponding PWR's value so that increasing the power density by improving heat transfer is strongly desired. The standstill can be broken through by adopting gas-solid suspension medium. Its heat transfer performance is quite excellent. Its heat capacity can be increased drastically without excessive pressurization. Although the thermal radiation is a dominant heat transfer mode in high temperature region, the ...
Lead-free piezoelectric ceramics (1-x)K0.5Na0.5NbO3-xAgSbO3+0.75 mol % MnO2 were prepared by a conventional solid-state sintering technique, and the piezoelectric and dielectric properties of the ceramics were studied. The results of x-ray diffraction suggest that AgSbO3 diffuses into the K0.5Na0.5NbO3 lattices to form a new solid solution with a single-phase orthorhombic perovskite structure. After the addition of AgSbO3, the paraelectric cubic-ferroelectric tetragonal phase transition temperature (TC) and the ferroelectric tetragonal-ferroelectric orthorhombic phase transition temperature (TO-T) decrease, and the ceramics become ``softened,'' resulting in significant improvements in the ferroelectric and piezoelectric properties. The ceramics with x=0.03-0.10 exhibit excellent piezoelectric properties: d33=130-216 pC/N, kp=0.44-0.51, and kt=0.40-0.52. The ceramics also exhibit a ...
Better understanding and modelling of three-phase flow through porous media is of great interest, especially for improved oil recovery methods such as gas injection processes. Early theoretical and experimental studies have already demonstrated that the wettability characteristics of the solid surface and the spreading characteristics of the fluid system hold the key roles. This observation is confirmed by our theoretical results using DLP theory on the stability and the thickness of static oil films. In most of the works related to three-phase flow processes, homogeneous wettability is assumed. There exist only a few studies demonstrating the tremendous impact of the wettability heterogeneities on gas injection. The objective of the present work is twofold: to demonstrate the effect of small scale wettability heterogeneities on gas injection efficiency, and to develop a tool to predict this impact for various patterns and ...
Single crystals of U(Ni_1_-_xPd_x )_2Si_2 for x = 0.05, 0.10 and 0.15 have been grown. Magnetization and electrical resistivity measurements were performed in a wide range of temperatures, magnetic fields and high pressures in order to study stability of magnetic phases in the solid solutions between UNi_2Si_2 and UPd_2Si_2 with a special emphasis on the type of ground state. In UPd_2Si_2 the simple AFI-type antiferromagnetic structure of U moments is observed at low temperatures. UNi_2Si_2 adopts the uncompensated AF structure (UAF) with the ++- stacking of U moments along the c-axis and consequently this compound exhibits a spontaneous magnetization corresponding to 1/3 of the U moment. The substitution of Pd for Ni leads to a rapid decay of the spontaneous magnetization. The evolution of magnetization and electrical resistivity behavior with Pd doping is tentatively attributed to the coexistence of the AF-I and UAF ...
Solid-phase extraction and gas chromatography with electron-capture detection has been used for sensitive, simple, and reliable analysis of carfentrazone-ethyl residues in water. Carfentrazone-ethyl was enriched by use of multiwalled carbon nanotubes (MWCNT), a new adsorptive material. Several conditions affecting recovery of the analyte, for example polarity and volume of eluents, pH of water samples, and sample volume, were studied. Recovery from fortified samples, linear range, and limit of detection were evaluated. The results showed that MWCNT are an efficient SPE adsorbent for preconcentration of carfentrazone-ethyl in water. Under the optimized SPE conditions, recovery of carfentrazone-ethyl from fortified water was 81.49?91.08%, with RSD from 1.66 to 8.21%. The limits of detection ...
We have studied in detail the transient enhanced diffusion observed during furnace or rapid-thermal-annealing of ion-implanted Si. We show that the effect originates in the trapping of Si atoms by dopant atoms during implantation, which are retained during solid-phase-epitaxial (SPE) growth but released by subsequent annealing to cause a transient dopant precipitation or profile broadening. The interstitials condense to form a band of dislocation loops located at the peak of the dopant profile, which may be distinct from the band formed at the original amorphous/crystalline interface. The band can develop into a network and effectively getter the dopant. We discuss the conditions under which the various effects may or may not be observed, and discuss conflicting observations on As"+ implanted Si.
The authors have studied in detail the transient enhanced diffusion observed during furnace or rapid-thermal-annealing of ion-implanted Si. The authors show that the effect originates in the trapping of Si atoms by dopant atoms during implantation, which are retained during solid-phase epitaxial (SPE) growth but released by subsequent annealing to cause a transient dopant precipitation or profile broadening. The interstitials condense to form a band of dislocation loops located at the peak of the dopant profile, which may be distinct from the band formed at the original amorphous/crystalline interface. The band can develop into a network and effectively getter the dopant. They discuss the conditions under which the various effects may or may not be observed, and discuss preliminary observations on As/sup +/ implanted Si. 12 references, 12 figures.
We have studied in detail the transient enhanced diffusion observed during furnace or rapid-thermal-annealing of ion-implanted Si. We show that the effect originates in the trapping of Si atoms by dopant atoms during implantation, which are retained during solid-phase-epitaxial (SPE) growth but released by subsequent annealing to cause a transient dopant precipitation or profile broadening. The interstitials condense to form a band of dislocation loops located at the peak of the dopant profile, which may be distinct from the band formed at the original amorphous/crystalline interface. The band can develop into a network and effectively getter the dopant. We discuss the conditions under which the various effects may or may not be observed, and discuss conflicting observations on As/sup +/ implanted Si.
The authors have studied in detail the transient enhanced diffusion observed during furnace or rapid-thermal-annealing of ion-implanted Si. The authors show that the effect originates in the trapping of Si atoms by dopant atoms during implantation, which are retained during solid-phase epitaxial (SPE) growth but released by subsequent annealing to cause a transient dopant precipitation or profile broadening. The interstitials condense to form a band of dislocation loops located at the peak of the dopant profile, which may be distinct from the band formed at the original amorphous/crystalline interface. The band can develop into a network and effectively getter the dopant. They discuss the conditions under which the various effects may or may not be observed, and discuss preliminary observations on As"+ implanted Si. 12 references, 12 figures.
The treatment of peat with the solutions of phosphoric, citric, and oxalic acids in concentrations of 10???4 and 10???2 mol/l at solidphase to liquid ratios of 1: 2.5 and 1: 5 increased the absorption of ammonia by 6.4???39.7%. The absorption of ammonia was higher than the concentration of doping ion-exchange groups by a factor of 5???2000. With the use of EPR and IR spectroscopy, it was found that this phenomenon was caused by the transformation of polyconjugation systems as a result of the interaction of acids with the organic matrix of peat by a macrocoordination mechanism, which also improved the technological characteristics of the resulting sorbents. The absence of the destruction of organic matter with the use of low concentrations of weak acids makes it possible to use these sorbe...
We have measured the almost-pure incoherent scattering function of liquid and solid parahydrogen, using inelastic neutron scattering. The experiments were carried out on TOSCA, a time-of-flight, inverse-geometry, crystal-analyzer spectrometer, operating on the pulsed neutron source at ISIS (UK). The experiments have been planned taking advantage of the intrinsic incoherence introduced in the scattering process by the rotational transitions. The measured double-differential cross section gives a direct experimental access to the microscopic dynamics of condensed hydrogen. From the high-energy region of the spectrum, where the impulse approximation for the center of mass motion applies, we have been able to extract the translational mean kinetic energy. In the low-energy region, using the Gaussian approximation, we compare the experimental data in the liquid phase with the results of a model for the velocity autocorrelation function. The results ...
Bilayers of pure palladium and gold films were evaporated alternatively on (100) and (111) monocrystalline silicon substrates. After annealing, in a vacuum furnace from 100 to 650degreeC during 30min, the growth sequence of the Pd2Si and PdSi phases that evolved as the result of the diffusion reaction was examined by means of Rutherford backscattering spectrometry (RBS), X-ray diffraction (XRD), whereas the surface morphology was investigated by scanning electron microscopy (SEM) technique. The effect of the intermediate gold layer is investigated in order to test its effectiveness as barrier for Cu and Si atoms interdiffusion and its influence on the morphology of the formed palladium silicides. The effect of substrate orientation on the palladium silicides growth and formation was also e...
A number of materials of composition YSr{sub 2}Cu{sub 3-x}MxO{sub 7{+-}y} with M = Ti, Fe, Co, Al, Ga and Pb were prepared by solid state reactions. They belong to the tetragonal P4/mmm space group and their unit cell parameters were determined and refined from X-ray powder data. The infrared spectra of the compounds were also recorded and are briefly discussed on the basis of their structural characteristics and by comparison with those of related materials. (orig.) 23 refs.
The spontaneous precipitation of calcium sulfate in supersaturated solutions over the temperature range between 25.0 and 80.0 C was investigated by monitoring the solution specific conductivity during desupersaturation. From measurements of the induction times preceding the onset of precipitation the surface energy of the forming solid, identified as gypsum, was found between ca. 12 and 25 mJ/m{sup 2} for the temperature range between 80.0 and 25.0 C, respectively. Kinetics analysis showed that over 50 C it is possible that anhydrous calcium sulfate is forming as a transient phase converting into the more stable calcium sulfate dihydrate. The linear dependence of the rates of precipitation on the relative solution supersaturation suggested a mechanism according to which the growth units are integrated into the active sites of the supercritical nuclei by surface diffusion. According to the morphological examination of the crystals it is possible ...
The redistribution of implanted As and Sb following metal-silicide formation of Pt, Pd, and Ni has been studied. The phases of the silicides used were PtSi, Pd/sub 2/Si, and NiSi. Investigations with Rutherford backscattering analysis showed that after the formation of the silicides, the Sb was always found in the silicide layer near the surface of the samples, whereas PtSi and Pd/sub 2/Si caused a partial rejection of As for implanted doses of 2 x 10/sup 15/ cm/sup -2/ and higher. No rejection of As was found after the formation of NiSi. The results are discussed in terms of solid solubilities and impurity-metal compound formation. The data presented has implications in the fabrication of Ohmic contacts and the adjustments of the heights of Schottky barriers on silicon.
The redistribution of implanted As and Sb following metal-silicide formation of Pt, Pd, and Ni has been studied. The phases of the silicides used were PtSi, Pd_2Si, and NiSi. Investigations with Rutherford backscattering analysis showed that after the formation of the silicides, the Sb was always found in the silicide layer near the surface of the samples, whereas PtSi and Pd_2Si caused a partial rejection of As for implanted doses of 2 x 10"1"5 cm"-"2 and higher. No rejection of As was found after the formation of NiSi. The results are discussed in terms of solid solubilities and impurity-metal compound formation. The data presented has implications in the fabrication of Ohmic contacts and the adjustments of the heights of Schottky barriers on silicon.
There have been several reports of transient-enhanced diffusion during furnace or rapid thermal annealing of ion-implanted silicon and some reports of no enhancement. In this contribution, the authors show that many of the observed effects can be accounted for by an interstitial trapping mechanism, in which large numbers of Si atoms are trapped by group V dopant atoms in the amorphous material during implantation. These trapped atoms are retained during solid-phase-epitaxial (SPE) growth, but can be released later during thermal processing to give the transient-enhanced diffusion. The authors present a model which can predict the transient effects (or lack of them) for any concentration of Sb, Bi, or As dopants sufficient to amorphize the silicon and any thermal processing technology which relies on SPE growth (furnace, cw laser, or rapid thermal annealing).
Porous ?-SiAlON ceramics are synthesized by reaction bonded method using hollow alumina spheres (HASs) as both sintering aids and pore-forming agents. Both micropores and macropores, which are constructured by SiAlON grains with different morphologies, are formed in the final SiAlON samples. The micropores are three-dimentional, and are built by equiaxial grains. While the hollow macropores, which have the similar morphology to hollow alumina sphere, are packed by elongated grains. In the sintering process, the solid dissolution process takes place, giving rise to the different alumina concentration of liquid phase, and thus resulting in the formation of two kinds of grains, the equiaxial grain and the elongated grain.
Pre-amorphization of ultrashallow implanted boron in Silicon-on-insulator is optimized to produce an abrupt box-like doping profile with negligible electrical deactivation and significantly reduced transient enhanced diffusion. The effect is achieved by positioning the as-implanted amorphous/crystalline interface close to the buried oxide interface, to minimize interstitials whilst leaving a single-crystal seed to support solid-phase epitaxy. Based on a simple physical model of our results, we estimate that the interface between the Si overlayer and the buried oxide is an efficient interstitial sink with a recombination length of the order of 10nm or less under our experimental conditions. (author)
The crystal structure of Ca{sub 2}RuD{sub 6} has been determined by neutron powder diffraction: space group Fm3m, K{sub 2}PtCl{sub 6} structure, as found for other hexahydride salts of group 8 metals with alkaline earth or lanthanide counter ions. No structural phase transition was observed between 340 K and 50 K. The deuterium nuclear quadrupole coupling constant, 54.7 kHz, leads to an ionic character of the Ru-D bond of 76%. The known trends in the behaviour of A{sub 2}MH{sub 6} salts are interpreted in terms of the ionization energies of the cation and the central metal atom.
The crystal structure of Ca2RuD6 has been determined by neutron powder diffraction: space group Fm3m, K2PtCl6 structure, as found for other hexahydride salts of group 8 metals with alkaline earth or lanthanide counter ions. No structural phase transition was observed between 340K and 50K. The deuterium nuclear quadrupole coupling constant, 54.7kHz, leads to an ionic character of the Ru-D bond of 76%. The known trends in the behaviour of A2MH6 salts are interpreted in terms of the ionization energies of the cation and the central metal atom.
We obtain x-ray absorption near-edge structures (XANES) by solving the equation of motion for the two-particle Green's function for the electron-hole pair, the Bethe-Salpeter equation (BSE), within the all-electron full-potential linearized augmented plane wave method (FPLAPW). The excited states are calculated for the Li K-edge in the insulating solids LiF, Li_2O and Li_2S, and absorption spectra are compared with independent particle results using the random phase approximation (RPA), as well as supercell calculations using the core-hole approximation within density functional theory (DFT). The binding energies of strongly bound excitations are determined in the materials, and core-exciton wavefunctions are demonstrated for LiF.
Summary The aroma impact volatiles of twenty-four pine honey samples produced in Marmaris, Data and Fethiye regions of Turkey were evaluated by solidphase micro extraction/gas chromatography/mass spectrometry (MS) technique and the results were evaluated by using the analysis of variance and Duncan tests. A total of eight common volatiles nonanal, nonanol, decanal, octanal, 16-oxosalutaridine, dodecanal, nonadecane and pentadecane were detected in three regions. The total area of the common volatiles were 73.01%, 78.10% and 73.91% in Marmaris, Data, and Fethiye regions, respectively. There were not significant differences (P-<-0.05) between the common volatiles detected in pine honey samples from three different regions. The major contributers to the pine honey aroma seems to be nonanal (...
Stability and decomposition of PtSi, NiSi, and PdSi in contact with single crystal or amorphous Si is examined. PtSi, PdSi and NiSi are thermally stable both with Si, but are unstable in contact with metal film. It is shown that epitaxial Si layers can be obtained using both Pd and Al as metal film and layers can be electrically doped by the addition of a doping layer to the thin film structure prior to the heat treatment or by inclusion of Al atoms so that n/sup +/ and p/sup +/ conductivity can be achieved in the grown epilayer. The effects of impurities, substrate orientation on the growth kinetics are also discussed. (LEW)
A study was made into microstructure and texture of cold rolled titanium alloy VT-35 with various hydrogen content aimed to reveal hydrogen influence on the mechanism of cold plastic deformation by rolling. Experiments were carried out using sheets 1.2 mm thick hydrogenated up to hydrogen concentrations from 0.06 to 0.554 mass. %. All specimens constituted a single-phase FCC #beta#-solid solution. It is shown that small hydrogen additions have a plasticizing effect on #beta#-titanium alloys in their cold rolling. The character of texture is dependent on hydrogen concentration and determined by deformation mechanism. 6 refs.; 5 figs.
Although thee are descriptions of a range of radioimmunoassays for human prolactin in various biological fluids, only one of these is an homologous assay using human prolactin as the reference standard and tracer as well and an anti-human prolactin antiserum (Sinha, Y.N., Selby, F.W.; Lewis, U.; and Vanderlaan, W.P., 1973, J. Clin. Endocr., Vol. 36, 509). A homologous radioimmunoassay using human putuitary prolactin has been developed. The separation method is based on the double antibody solidphase system. Cross reactivity with human growth hormone (GH), placental lactogen (HPL), the pituitary protein hormones and prolactins of various species were studied as were values found in normal subjects in basal conditions and after a TRH injection. (author).
Sintered glass-ceramics have been produced using municipal incinerator solid residues and glass cullet or an inert waste, from feldspars processing, as sintering aids. The capability of three different mixtures, either previously vitrified or not, to be sintered was investigated by means of linear shrinkage, water absorption and bulk density measurements, and by X-ray diffraction analysis and scanning electron microscopy observations. Particular attention has been addressed to the study of particle size effect on the sintering process. The conclusions that can be drawn from the experimental study are that the preliminary vitrification step is essential in order to obtain a dense sintered glass-ceramic product in the 850-1050 C temperature range developing silicate crystalline phases. The optimal powder particle size that confers a good densification degree was found to be < 45 {mu}m. (orig.)
The effect of the composition of multicomponent Zr-Ti-V-Mn-Cr-Ni alloys on their hydrogen-storage capacity and on the rate of electrosorption/desorption hydrogen was investigated under potentiodynamics as well as single-pulse and long-term galvanostatic conditions. The main characteristics of alloys and alloy electrodes were determined by their structural analysis by means of X-ray diffraction and scanning electron microscope, by specific surface area test and by determination of the hydrogen absorption/desorption isotherms in the gas/solidphase system. It was found that only the alloys with a manganese content below a threshold could be used as electrode materials for Ni-MH batteries, whereas the modification of the electrode material by micro-encapsulation of alloy particles should limit the dissolution of manganese from the electrode material in a strong alkaline solution. (orig.)
A series of cyclic voltammetry, chronoamperometry and electrochemical impedance experiments have been carried out in order to investigate the effect of cathode composition and porosity on the electrochemical characteristics of strontium-doped lanthanum, praseodymium and gadolinium cobaltite cathodes. The impedance responses at different electrode potentials of the half cell and symmetric single cell setups are compared and analyzed by the equivalent circuit modeling method. The deconvolution of impedance spectra for single cell cathode and anode reactions contributions based on the results of simultaneous analysis of half cells and symmetric single cells has been made by differential impedance real part vs. ac frequency plot analysis method. Noticeable influence of cathode chemical composition, meso-porosity and macro-porosity on the electrochemical activity of the oxygen electroreduction has been demonstrated. Seeming activation energy values have been calculated and discussed.
Ferroelectric [Pb_0_._9_2(La_1_-_zSb _z)_0_._0_8][Zr_0_._6_0Ti_0_._4_0]O_3 for z = 0.0, 0.3, 0.6, 0.9 and 1 were prepared from their constituent oxides by a solid state reaction technique. The powders were calcined in the temperature range of 1000 deg. C for 6 h. Phase formation, crystal structure and lattice parameter were investigated by X-ray diffraction (XRD) technique. The compacts were sintered at 1250 deg. C for 2 h and their dielectric, ferroelectric and conductive properties were measured. The ferroelectric behavior of the doped samples was studied from their hysteresis loop.
Breath analysis could offer a non-invasive means of intravenous drug monitoring if robust correlations between drug concentrations in breath and blood can be established. In this study, propofol blood and breath concentrations were determined in an animal model under varying physiological conditions. Propofol concentrations in breath were determined by means of two independently calibrated analytical methods: continuous, real-time proton transfer reaction mass spectrometry (PTR-MS) and discontinuous solid-phase micro-extraction coupled with gas chromatography mass spectrometry (SPME-GC-MS). Blood concentrations were determined by means of SPME-GC-MS. Effects of changes in pulmonary blood flow resulting in a decreased cardiac output (CO) and effects of dobutamine administration resulting in...
Among pharmaceuticals and personal care products released into the aquatic environment, antibiotics are of particular concern, because of their ubiquity and health effects. Although scientists have recently paid more attention to the threat of antibiotics to coastal ecosystems, researchers have often focused on relatively few antibiotics, because of the absence of suitable analytical methods. We have therefore developed a method for the rapid detection of 36 antibiotic residues in coastal waters, including tetracyclines (TCs), sulfanilamides (SAs), and quinolones (QLs). The method consists of solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, using electrospray ionization (ESI) in positive mode. The SPE was performed with Oasis HLB and Oasi...
We have investigated B diffusion in pre-amorphized silicon. In our experiments, the crystalline surface layer of silicon-on-insulator (SOI) substrates was completely amorphized by Ge ion implantation. Using SOI substrates in this fashion suppressed solid-phase-epitaxy regrowth, making it possible to investigate B diffusion in pre-amorphous silicon over a wider range of temperatures (500-650 deg. C) and times (5-1000 s) than has previously been reported. Diffusivities were determined with the aid of computational processes modeling. The results from this work demonstrate the B diffusion in a-Si is concentration dependent, exhibits a transient enhanced diffusion, and possesses an Arhennius behavior with activation energy of {approx}2.1 eV.
We have investigated B diffusion in pre-amorphized silicon. In our experiments, the crystalline surface layer of silicon-on-insulator (SOI) substrates was completely amorphized by Ge ion implantation. Using SOI substrates in this fashion suppressed solid-phase-epitaxy regrowth, making it possible to investigate B diffusion in pre-amorphous silicon over a wider range of temperatures (500-650 deg. C) and times (5-1000 s) than has previously been reported. Diffusivities were determined with the aid of computational processes modeling. The results from this work demonstrate the B diffusion in a-Si is concentration dependent, exhibits a transient enhanced diffusion, and possesses an Arhennius behavior with activation energy of #approx#2.1 eV.
Sales of iodized table salt (household use, bulk containers) have been flat in Germany since 1996/1997. Nevertheless, the amount of iodide excreted with the urine has been steadily increasing in the German population since 1993. We investigated the beverage iodine levels as possible source of the increased input of iodine into the food chain. No systematic studies on this topic have yet been carried out in Germany. A total of 510 samples were drawn from large grocery discounters who supply all German states with their products (35% fruit and vegetable juices, 35% beers, 10% pooled milk and yoghurt drinks, 10% mineral water, 10% soda). (1) Water-based beverage samples are prepared by solid-phase extraction and iodine concentration is determined by HPLC and electrochemical detection, (2) the...
Abstract In the work, a rapid, simple and high-throughput sample preparation method was developed for the determination of sulfonamide (SA) antibiotic residues in chicken breast muscle. The extraction and clean-up were online combined and up to 20 samples can be treated simultaneously in 6-min. The SAs were first extracted with acetonitrile under the action of microwave energy, and then the extract was directly introduced into the SPE column for on-line clean-up and concentration. Subsequently, the SAs eluted from the SPE column were determined by liquid chromatography-tandem mass spectrometry. The precisions of extraction results of 20 samples were in the range of 4.9-7.4%. The limits of detection and quantification obtained were in the range of 2.4-3.6-ng/g and 8.6-11.3-ng/g for SAs, res...
Apparatus for solid-phase antibody separation techniques used in radioimmunoassays is described in this invention. It consists of a rectangular prism tray with multiple wells protruding into its interior from one side. Near the base of the tray is an orifice used for creating evacuated condition within the structure. At the base of each well there is an orifice of such size and shape as to retain an aqueous liquid under given pressure conditions but permit the evacuation of this liquid at reduced pressure. The outlet of these orifices is in the shape of an inverted conical frustrum. Each of the wells contains an antibody coated disc of porous cellulose paper surrounded by a plastic support. The porous nature of the cellulose paper ensures contact between the antibody coating and the antigen. The use of antibody coated porous cellulose paper in combination with the vacuum operated apparatus simplifies the manipulative steps whilst still maintaining the sensitivity ...
Fermented sausages were produced with 25%, 50%, 75% or 100% of their pork back fat content replaced by amorphous cellulose gel. The sausage production was monitored with physical, chemical and microbiological analyses. The final products were submitted to a consumer study, and the volatile compounds of the final products were extracted by solid-phase microextraction and analyzed by GC/MS. The reformulated fermented sausages had significant reductions in fat and cholesterol, and the volatile compounds derived from lipid oxidation were also reduced in the final products. These results suggest that the substitution of up to 50% of the pork back fat content by amorphous cellulose gel can be accomplished without a loss of product quality, enabling the production of fermented sausages with the l...
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.
Correlations between structural aspects of solid materials and their behavior as catalysts are relatively recent. This 20-chapter book focuses on understanding of solid-state mechanisms in heterogeneous catalysis and relationship between catalytic behavior and solid state structure, emphasizing catalysis with oxides, sulfides, and zeolites.
The solid particle movement in a rotary drum plays an important role in drying processes. The solid distribution in the drum affects the amount of contact surface between the solid and the gas. The retention time of solids influences the time particles can stay in contact with the gas in order to transfer heat and mass. Any heat and mass transfer model for a solid particle dryer must be able to predict solid flowrate and solid hold-up. There have been several reports in the literature regarding the modeling aspects of solid transport in dryers. If the model is developed for model-based control, it must be simple and yet represent dynamics of the system accurately. This paper addresses solid motion modeling and the effects of different variables involved in solid transport ...
We discuss the transient-enhanced diffusion of Sb, As, P, In, Ga, and B in ion-implanted Si, where the near-surface region has been amorphized by the dopant or by a self-implantation process. With Sb, a large transient diffusion enhancement is observed proportional to dopant concentration. For Sb, As, P, and In, the enhancement follows the relative interstitialcy diffusion coefficient. We believe this behavior is caused by stable implantation-induced point defects present in the amorphous surface layer, which decay during thermal processing to release high concentrations of self-interstitials. This process occurs in competition with the solidphase epitaxial (SPE) growth process, and for high dopant concentrations can occur in the amorphous phase ahead of the crystallization front. We believe this may be the origin of the dopant redistribution which can occur during SPE growth, which sets the upper limit to the dopant ...
Abstract A series of compounds with the general formula (La1-xSmx)2Ti2O7 (0-- x --1.0) has been synthesized by a sol-gel method and characterized by XRD, Raman spectroscopy, and scanning electron microscopy (SEM). These compounds are structurally isomorphic to perovskite-type La2Ti2O7 until a substitution rate of x = 0.8. Above this substitution rate (x >-0.8), a biphasic mixture is obtained between the substituted perovskite layered phase and the pyrochlore Sm2Ti2O7 phase. The unusual phosphor (La1-xSmx)2Ti2O7 has been elaborated and its luminescent properties were investigated for low rates of substitution. The emission and excitation spectra were used to study the luminescent properties. The (La1.9Sm0.1)2Ti2O7 powders emit bright red-orange lightunder UV excitation. The emission propert...
An alkali metal manganese oxide secondary cell is disclosed which can provide a high rate of discharge, good cycling capabilities, good stability of the cathode material, high specific energy (energy per unit of weight) and high energy density (energy per unit volume). The active material in the anode is an alkali metal and the active material in the cathode comprises an orthorhombic alkali metal manganese oxide which undergoes intercalation and deintercalation without a change in phase, resulting in a substantially linear change in voltage with change in the state of charge of the cell. The active material in the cathode is an orthorhombic structure having the formula M.sub.x Z.sub.y Mn.sub.(1-y) O.sub.2, where M is an alkali metal; Z is a metal capable of substituting for manganese in the orthorhombic structure such as iron, cobalt or titanium; x ranges from about 0.2 in the fully charged state to about 0.75 in the fully discharged state, and y ranges from 0 to ...
The US Department of Energy (DOE) has millions of gallons of high level nuclear waste stored in underground tanks at Hanford, Washington and Savannah River, South Carolina. These tanks will eventually be emptied and decommissioned. This will leave a residue of sludge adhering to the interior tank surfaces that may contaminate nearby groundwaters with radionuclides and RCRA metals. Performance assessment (PA) calculations must be carried out prior to closing the tanks. This requires developing radionuclide release models from the sludges so that the PA calculations can be based on credible source terms. These efforts continued to be hindered by uncertainties regarding the actual nature of the tank contents and the distribution of radionuclides among the various phases. In particular, it is of vital importance to know what radionuclides are associated with solid sludge components. Experimentation on actual tank sludges can be difficult, dangerous ...
This work presents comparative results of a numerical investigation of four possible models for the prediction of thermal performance of fixed bed storage units and their thermal design. These models includes Schumann's model, the radial dispersion model, a model that include both axial heat conduction in the fluid phase and admits thermal gradient in the solids particles and finally a two dimensional single phase model. For each of these models a computer code was written and tested to evaluate the computing time of same data and analyze any other computational problems. The tests of thermal performance included particle size, porosity, particle material, flow rate, inlet temperature and heat losses form tank walls and extremities. Dynamics behaviour of the storage units due to transient variation in either flow rate or inlet temperature was also investigated. The results presented include temperature gradients, ...
Several U.S. Department of Energy organizations and the U.S. Bureau of Mines have been collaboratively conducting mixed waste treatment process demonstration testing on the near full-scale graphite electrode submerged arc melter system at the Bureau`s Albany (Oregon) Research Center. An initial test series successfully demonstrated arc melter capability for treating surrogate incinerator ash of buried mixed wastes with soil. The conceptual treatment process for that test series assumed that buried waste would be retrieved and incinerated, and that the incinerator ash would be vitrified in an arc melter. This report presents results from a recently completed second series of tests, undertaken to determine the ability of the arc melter system to stably process a wide range of {open_quotes}as-received{close_quotes} heterogeneous solid mixed wastes containing high levels of organics, representative of the wastes buried and stored at the Idaho National Engineering ...
Three types of titanium hydrides have been reported: #delta#, #epsilon# and #gamma# hydrides. The #delta# hydride forms in the composition range from TiH/sub 1.5/ to TiH/sub 1.99/ and has a CaF/sub 2/ structure with metal atoms on an fcc lattice and hydrogen atoms randomly occupying tetrahedral interstitial sites. At higher hydrogen concentrations, TiH/sub 2/, the fct (c/a # #epsilon# transformation is apparently diffusionless, similar to that operating in the cubic/tetragonal transformation in zirconium hydride. The metastable fct #gamma# hydride having a c/a value of 1.09 or 1.12 forms from solid solutions of hydrogen in the hcp #alpha# matrix. While the titanium hydride precipitation in #alpha#-Ti and its alloys has attracted extensive investigation, hydride formation in bcc #beta#-Ti alloys has rarely been studied because they have not been thought to be liable to hydride formation. This paper shows conclusive evidence for the fcc #delta# hydride ...
Crude oil-polluted soil (five parts of weathered crude oil per 100 parts of soil; equivalent to 50,000 mg oil kg{sup -}1 soil) samples were slurried in deionised water (300% of the water retention capacity of the soil) and treated with various amounts of natural-rubber processing sludge (nitrogen content 62.15 mgkg{sup -1} and phosphorus contents 8.75 mgkg{sup -1}) in a well-stirred, continuously-aerated tank at 29{sup o}C. Changes in the total hydrocarbon content of the soil sample were determined, using a spectrophotometric technique, as a function of time. The extent of crude oil degradation was markedly higher (by up to 100%) in the sludge-treated soil than in the untreated soil sample. The efficiency of biodegradation of the crude oil hydrocarbons using the slurry-phase technique was compared with that of solid-phase technique. (author)
The University of Georgia, in collaboration with GE Global Research, has investigated the relevant quenching mechanism of phosphor coatings used in white light devices based on UV LEDs. The final goal of the project was the design and fabrication of a high-efficacy white light UV-LED device through improved geometry and optimized phosphor coatings. At the end of the research period, which was extended to seamlessly carry over the research to a follow-up program, we have demonstrated a two-fold improvement in the conversion efficiency of a white light LED device, where the increase efficacy is due to both improved phosphor quantum efficiency and lamp geometry. Working prototypes have been displayed at DOE sponsored meetings and during the final presentation at the DOE Headquarters in Washington, DC. During the first phase of the project, a fundamental understanding of quenching processes in UV-LEDs was obtained, and the relationships that describe the performance of ...
The University of Georgia, in collaboration with GE Global Research, has investigated the relevant quenching mechanism of phosphor coatings used in white light devices based on UV LEDs. The final goal of the project was the design and fabrication of a high-efficacy white light UV-LED device through improved geometry and optimized phosphor coatings. At the end of the research period, which was extended to seamlessly carry over the research to a follow-up program, we have demonstrated a two-fold improvement in the conversion efficiency of a white light LED device, where the increase efficacy is due to both improved phosphor quantum efficiency and lamp geometry. Working prototypes have been displayed at DOE sponsored meetings and during the final presentation at the DOE Headquarters in Washington, DC. During the first phase of the project, a fundamental understanding of quenching processes in UV-LEDs was obtained, and the relationships that describe the performance of ...
A joint US/Russia program is being conducted to develop, fabricate, launch, and operate a solar dynamic demonstration system on Space Station Mir. The goal of the program is to demonstrate and confirm that solar dynamic power systems are viable for future space applications such as the International Space Station Alpha. The major components of the system include a heat receiver, a closed Brayton cycle power conversion unit, a power conditioning and control unit, a concentrator, a radiator, a thermal control system, and a Space Shuttle carrier. This paper discusses the design of the heat receiver component. The receiver comprises a cylindrical cavity, the walls of which are lined with a series of tubes running the length of the cavity. The engine working fluid, a mixture of xenon and helium, is heated by the concentrated sunlight incident on these tubes. The receiver incorporates integral thermal storage, using a eutectic mixture of lithium fluoride and calcium difluoride as the thermal ...
The crystal structure and phonon densities of states (DOS) of #beta#'-SiAlON ceramics, Si_6_-_zAl_zO"zN_8_-_z (0 #<=# z #<=# 4), prepared by a novel slipcast method, are studied by neutron-scattering techniques. The samples with z < 4 form a single-phasesolid solution of Si-Al-O-N isostructural to #beta#-Si_3N_4 (space group P6_3/m). A consistent preferential occupation of the 2c sites by oxygen atoms and the 6h sites by nitrogen atoms exists within this structure. The phonon DOS of #beta#'-SiAlON displays phonon bands at #approx#50 and 115 meV. These features are considerably broader than the corresponding ones in #beta#-Si_3N_4 powder.
Concerning high performance composite solid propellant BAMO and BAMO-based copolymers, synthetic method and properties of them were studied. Comparison graph of theoretical specific impulse for various propellants were shown, by that, reason why highest specific impulse BAMO was selected as direction of the study. As the orientation of synthesis, those were indicated that radicals at both ends should be hydroxyl so as urethane bonding was available, that liquid at normal temperature was required for easy handling, and that glass transition temperature is required to be low enough. Synthesis was conducted by ring-opening polymerization of ring ether detail procedures of which were explained. Measurements of properties was performed for thermochemical properties, thermal decomposition, combution heat, and friction sensitivity test to confirm safety. As the result, those were understood that thermal decomposition was divided into two phases, rapid ...
Commercial introduction of new polymer materials for use as the electrolyte in solid tantalum and solid aluminum electrolytic capacitors is underway. ...
Executive summaryForewordPublic awareness of solid-state chemistry, or more broadly solid-state science and technology rapidly grew along with the transistor revolution and the development of the integrated circuit. We are now at the half-way point in the solid state century [Scientific American The Solid-State Century 1997;8(1) [special issue
Two-phase flow patterns and frictional pressure gradients in flow in small, rectangular channels are being studies as part of a larger research program addressing phase-change heat transfer of pure refrigerants and refrigerant mixtures in plate-fin heat exchangers. Small rectangular flow channels were selected as representative of plain fin geometries. The particular channel reported herein has dimensions of 19.05 {times} 3.18 mm. Adiabatic flows of air/water mixtures, with the flow channel horizontal and the channel exit at near-atmospheric conditions, were utilized in the experiments. Analysis and interpretation of the pressure data relative to observed flow pattern transitions led to an objective method for determining the plug/bubble-to-slug flow transition. This method, together with visual observations, supplemented with photographic data, was used to develop a flow pattern man. A comparison of existing flow pattern maps for circular ...
Initial major applications of neutron radiography (NR) to nuclear engineering were nondestructive inspections of nuclear fuel, control rods, reactor materials and some other components. Increase in the available neutron flux over 10{sup 8} n/cm{sup 2}s at the JRR-3M thermal neutron radiography facility (TNRF) in 1991 has expanded the application field to the dynamic but clear imaging of moving objects and fluid phenomena. The JRR-3M TNRF is facilitated with three major imaging systems, being characterized by spatial and/or temporal resolutions: 1. Static neutron radiography (SNR), 2. real-time neutron radiography (RNR) with an imaging rate of 30 frames/s and 3. High-frame-rate neutron radiography (HFRNR). SNR has been used for three-dimensional visualization of air-water two-phase flows in a simulated rod bundle. Three-dimensional computed tomography clearly illustrated average void fraction distributions around tie spacers. RNR has been used for visualization and ...
The decision of the United Kingdom to adopt a policy of solidification of high level waste had led to renewed interest in vitrification. The HARVEST process chosen is an adaptation of the FINGAL concept developed at Harwell 15 years ago. Because of certain changes in engineering design and differences in the composition of the waste, additional chemical engineering data are required for HARVEST. The new inactive pilot plant has been built to provide this information. Its size is virtually full-scale and batches of glass up to 1 tonne can be manufactured in vessels of diameter up to 750mm. Five glass-making runs have been carried out. Attention has concentrated on the performance of the off-gas system which employs wet methods. Carry-over of solids occurs, primarily as a result of physical entrainment. The carry-over of synthetic fission products is improved from 2.5 to 0.1% by directing the feed down the vessel walls. Most of the entrained ...
The heat transfer augmentation effect by the unsteady heat conduction between the particles and heat transfer surface is one of the main factors, causing the heat transfer augmentation around the stagnation point in the gas-solid two-phase impinging jet flow. By separating and evaluating that effect, material influence on it was studied of particles and heat transfer surface, together with change by the jet flow condition. That effect enlarged with enlarging in heat capacity, multiplied by the heat conduction coefficient, of both the particles and heat transfer surface, and if both of them were constant in material combination, was dominated by the contact frequency of particles per unit time. Therefore in case of lading solid particles, equal in weight, that effect enlarges with diminishing in particle diameter. Such a heat transfer augmentation mechanism model is universally applicable to the data by Yoshida et al., using ...
Lithium ion conducting glass ceramics composed of the crystalline conductive phase Li{sub 1.4}Al{sub 0.4}(Ge{sub 1-x}Ti{sub x}){sub 1.6}(PO{sub 4}){sub 3}(x=0-1.0) with the Nasicon-type structure have been synthesized and characterized by DTA, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and complex impedance techniques. The experimental results indicated that the glass ceramics were mainly composed of solid solution Li(Ge{sub 1-x}Ti{sub x}){sub 2}(PO{sub 4}){sub 3} formed by LiGe{sub 2}(PO{sub 4}){sub 3} and LiTi{sub 2}(PO{sub 4}){sub 3} in the whole x range and showed conductivity over 10{sup -4} S/cm at room temperature. The maximum room temperature lithium ion conductivity of 6.21x10{sup -4} S/cm with an activation energy as low as 0.32 eV was obtained for the Li{sub 1.4}Al{sub 0.4}(Ge{sub 0.67}Ti{sub 0.33}){sub 1.6}(PO{sub 4}){sub 3} treated at 950 C for 18 h. Mechanisms for the enhancement of {sigma}{sub ...
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 withdraw solid matters deposited in the reactor, there are ...
A 'Laboratory of Quantitative Methods in Monument Research' is being built at the CTU Prague. Its primary orientation is the investigation of historic architecture, although other objects of art can also be investigated. In the first phase, two radiation methods are being established, but it is set up in such a way, that various other methods can readily be added in its future development. The radiation methods chosen for the initial development of the laboratory are: thermoluminescence dating and X-ray fluorescence analysis. The design of the automated TL-reader, built in our laboratories, is adjusted for the purpose of dating of historic brick architecture (which, of course, does not exclude applications for ceramics and other materials). The investigation of renaissance architecture in southern Bohemia and Moravia is under preparation as the first large campaign of this kind in the Czech Republic. Radionuclide X-ray ...
A 'Laboratory of Quantitative Methods in Monument Research' is being built at the CTU Prague. Its primary orientation is the investigation of historic architecture, although other objects of art can also be investigated. In the first phase, two radiation methods are being established, but it is set up in such a way, that various other methods can readily be added in its future development. The radiation methods chosen for the initial development of the laboratory are: thermoluminescence dating and X-ray fluorescence analysis. The design of the automated TL-reader, built in our laboratories, is adjusted for the purpose of dating of historic brick architecture (which, of course, does not exclude applications for ceramics and other materials). The investigation of renaissance architecture in southern Bohemia and Moravia is under preparation as the first large campaign of this kind in the Czech Republic. Radionuclide X-ray fluorescence analysis has ...
Biodiesel made from vegetable oil is among the most desirable of renewable energy sources because it can be a substitute for diesel oil. However, biodiesel from soybean or corn can be confronted with a food crisis. Microalgae is a new biodiesel source which contains high oil lipids with a high growth rate, and which also offers value-added products from the residue, such as cosmetics, health functional food or pharmaceuticals. Microalgae are best cultivated in photo-bioreactors (PBRs) where light, nutrients, carbon dioxide and temperature can be controlled. Despite the current availability of PBRs, only a few can be practically used for mass production. Computational fluid dynamics (CFD) was used in this study to design an optimum bubble-column PBR for mass production of microalgae. Multi-phase models including bubble movement, meshes and time step independent tests were considered to develop the 3-dimensional CFD model. Particle Image Velocimetry (PIV) tests were ...
The available experimental data on the specific heat, magnetic susceptibility, magnetization, valence, NMR Knight shift and relaxation rate, and the quadrupolar moment of YbPd_2Si_2 are examined within the framework of the single-ion Anderson model. Such an analysis has previously given excellent agreement between theory and experiment for numerous other light heavy-fermion compounds, where crystalline fields do not play a dominant role. For YbPd_2Si_2, substantial crystalline-field splittings make difficult a quantitative comparison with existing exact solutions of the Anderson model. Inconsistencies with the interpretation that a nearly degenerate ground quadruplet determines the low-temperature thermodynamics are pointed out. It is concluded that at least three of the four Kramers doublets participate in the low-T properties. These three doublets should have a splitting of the order of the Kondo temperature, i.e., about 100 K. A simple resonant-level model ...
The available experimental data on the specific heat, magnetic susceptibility, magnetization, valence, NMR Knight shift and relaxation rate, and the quadrupolar moment of YbPd{sub 2}Si{sub 2} are examined within the framework of the single-ion Anderson model. Such an analysis has previously given excellent agreement between theory and experiment for numerous other light heavy-fermion compounds, where crystalline fields do not play a dominant role. For YbPd{sub 2}Si{sub 2}, substantial crystalline-field splittings make difficult a quantitative comparison with existing exact solutions of the Anderson model. Inconsistencies with the interpretation that a nearly degenerate ground quadruplet determines the low-temperature thermodynamics are pointed out. It is concluded that at least three of the four Kramers doublets participate in the low-{ital T} properties. These three doublets should have a splitting of the order of the Kondo temperature, i.e., about 100 K. A simple ...
The microstructural development and grain-coarsening behavior of WC-Co alloys, with and without a VC additive, were investigated. The primary goal was to determine the mechanism through which VC acts as a grain-growth inhibitor. The study involved long-time sintering experiments (1 to 100 hours) on fully dense material, nascent stage sintering (90 to 1,320 seconds) starting with the green compact, and surrogate liquid phase experiments to characterize the WC powder prior to sintering. Quantitative microstructural analysis using intercept length distributions was performed for the long-term sintering. The nascent stage experiments involved the measurement of the specific surface area (S{sub v}) of each type of interface separately allowing the determination of the contribution of each developing entity to the overall microstructural evolution. The VC addition has been found to enhance the breakup of multigrained particles in the earliest stages ...
The microstructural development and grain-coarsening behavior of WC-Co alloys, with and without a VC additive, were investigated. The primary goal was to determine the mechanism through which VC acts as a grain-growth inhibitor. The study involved long-time sintering experiments (1 to 100 hours) on fully dense material, nascent stage sintering (90 to 1,320 seconds) starting with the green compact, and surrogate liquid phase experiments to characterize the WC powder prior to sintering. Quantitative microstructural analysis using intercept length distributions was performed for the long-term sintering. The nascent stage experiments involved the measurement of the specific surface area (S_v) of each type of interface separately allowing the determination of the contribution of each developing entity to the overall microstructural evolution. The VC addition has been found to enhance the breakup of multigrained particles in the earliest stages of ...
Motivated by recent experiments on KIF1A, a representative member of single-headed kinesin motor proteins family, we develop a theoretical model of intra-cellular transport by mutually interacting molecular motors. The model explicitly accounts not only for the hydrolysis of ATP, but also for the ratchet mechanism which is believed to drive each individual KIF1A motor. We study the model by a combination of analytical and numerical techniques. A remarkable feature of this model is that all the parameters in it can be completely evaluated from experimental data. Our results in the dilute limit are in excellent quantitative agreement with the empirical data from single molecule experiments. In the high density regime the predictions of the model also agree qualitatively with the corresponding experimental observations. We derive a phase diagram that shows the influence of hydrolysis and Langmuir kinetics on the collective spatio-temporal ...
Silicon nitride based ceramics have attracted considerable attention as good candidates for structural applications due to their excellent mechanical properties including strength, hardness, fracture toughness, and high temperature strength. These properties are strongly influenced by grain size and morphology, and by the degree of crystallinity and chemistry of grain boundary phases. In this work, the microstructure of Si{sub 3}N{sub 4} densified with Nd{sub 2}O{sub 3}, Y{sub 2}O{sub 3} and Al{sub 2}O{sub 3} sintering additives was studied. Sintered samples were polished and plasma etched for microstructural analysis using scanning electron microscope. Quantitative evaluation of materials microstructure was accomplished using Quantikov software. Fracture toughness was measured by Vickers indentation method. The observed microstructure is typical of silicon nitride based materials and is characterized by high aspect ratio.-Si{sub 3}N{sub 4} ...
Hepatobiliary scintigraphy is the only non-invasive technique providing real-time assessment of hepatocytes function and bile progression from the liver to the intestine; for this reason it is of great importance in the study of jaundice and many other disorders of the liver and the biliary tract in children. Ultrasonography is the initial method of evaluating the intra- and extrahepatic bile ducts dilatation: the differential diagnosis between biliary atresia and neonatal hepatitis cannot however be done without hepatobiliary scintigraphy. Cystic fibrosis patients also require hepatobiliary scintigraphy; liver and biliary tract disease can really occur independently of the underlying disease severity and the presence of steatorrhoea. Hepatobiliary imaging in children who have undergone liver transplantation is of major importance; it can assess vascularity, parenchymal function biliary drainage, possible presence of a bile leak and obstruction; it has very good sensitivity and ...
A number of fragment ion onsets from the photoionization of CH/sub 3/SCCSCH/sub 3/ and CH/sub 3/SSSCH/sub 3/ have been measured. In addition, our experiment has been converted to a molecular beam source which will increase the precision of our measurements. Exhaustive oxidation of the divalent sulfur to sulfonic acids serves to quench the effects of quadrupolar broadening and thereby allowing for quantitative evaluation of structurally similar sulfonic acids. W/sub 1/2/ are reduced to < 25 Hz at 19 MHz (57,500 Gauss). Electronegative substituents shield the /sup 33/S nucleus perhaps imploying more efficient 2p-3d..pi.. backbonding between sulfur and oxygen. ..cap alpha..-Hetero substituents of sulfonyl groups do not influence the shift of the /sup 33/S to a dramatic extent. The exception is the dianion of thiosulfate compared to the dianion of sulfate. Lanthanide shift reagents, (Eu(fod)/sub 3/), are potentially useful in distinguishing sulfonyl /sup 17/O shifts ...
Sterile aqueous N-methylaniline solutions were allowed to equilibrate at various nitrite, F-400 granular-activated carbon, and pH levels for 1 week. The aqueous and activated carbon phases were extracted and analyzed for nitrosamines relative to an added internal standard. Selected ion monitoring GC/MS, utilizing continuous monitoring of the NO/sup +/ ion (m/z 29.9980) characteristic of nitrosamines, at medium resolution (R = 2500-3000) was applied to quantitatively measure nitrosamines at picograms per microliter concentrations. This method selected for nitrosamine products only and eliminated interferences from non-nitrosamine reaction products. Results indicate that the pressure of granular-activated carbon significantly enhanced the formation of nitrosamine from N-methyl-aniline (F = 145, P< 0.0001). The amount of N-nitrosomethylaniline formed in the presence of activated carbon was 75 times more than that formed in the absence of ...
The Convective and Orographically-induced Precipitation Study (COPS) has the aim to advance the quality of forecasts of orographically-induced precipitation in complex terrain. COPS is a Research and Development Project of the World Weather Research Program and considered to be one of the largest field campaigns on quantitative precipitation forecasting that has been performed so far. A network of state-of-the-art active and passive remote sensing systems was combined with in total 10 airborne platforms, Meteosat rapid scans and dense networks of standard meteorological instruments during the three months long field phase (June-August, 2007) in south-western Germany/eastern France to observe atmospheric variables in the three spatial dimensions and in time. By the University of Hohenheim, two novel ground-based mobile scanning lidar systems were deployed: a scanning rotational Raman lidar which provides combined measurements of the field of ...
Solid oxide fuel cell (SOFC) is a promising source of power generation in terms of conversion efficiency which is higher than the conventional one, as it is not limited by the Carnot efficiency. Theoretically, the SOFC have an efficiency of the order of 60-80 % but it is limited by the number of active side available for the reaction i.e. TPB (triple phase boundary) at the electrode-electrolyte interface which depends on the particle size of the materials employed during the fabrication of SOFC components (i.e. the method employed during the synthesis). Literally, there are several methods used in the syntheses of oxide materials such as conventional solid-state reaction, co-precipitation, hydrothermal rout, sol-gel and Glycine nitrate process (GNP) but among these GNP found to be effective over the other because of homogeneity, phase purity and smaller particle size of final product. In this work, the ...
The effect of partial and total replacement of tungsten by molybdenum on the mechanical technical properties were investigated with the cold work steel 60 WCrV 7 (DIN 1.2550). While maintaining the total quantity of tungsten atoms and/or molybdenum atoms in the steel, no differences occur in the type of the separated carbides. After annealing in the range of the pearlite stage with annealing times of up to 150 h, the carbide phases M/sub 23/C/sub 6/ and MC are, besides alpha iron, also present. In short-time annealed states also M/sub 6/C carbides occur. These are formed during austeniting and remain in the steel as residual carbides in austeniting treatment carried out under normal conditions. Compared with tungsten alloyed steel, there is an increased formation of M/sub 6/C carbides in molybdenum alloyed steels during austeniting. By a long-time annealing treatment in the range of the pearlite stage, the M/sub 6/C carbides are dissolved in favour of the M/sub ...
"2"7Al and "2"9Si solid-state NMR spectra and X-ray diffraction (XRD) patterns were obtained for #alpha#-SiAlON powders prepared by combustion synthesis, according to which the phase transformation and structure evolution of #alpha#-SiAlON were studied. It was found that in #alpha#-SiAlON "2"9Si chemical shift values (-48 < #delta# _S_i < -47) were close to those in #beta#-Si_3N_4 and #alpha#-Si_3N_4, indicating that Si atoms kept SiN_4 coordination to a large extent in #alpha#-SiAlON despite the presence of O atoms. Dissimilarly, "2"7Al chemical shift values in #alpha#-SiAlON deviated clearly from that corresponding to AlN_4 coordination (#delta# _A_l #approx# 112) and occurred in a range from #delta# _A_l 95.5 to 99.9, which should be assigned to tetrahedral AlO _xN_4_-_x (0 #<=# x #<=# 4) coordination. The broadening effect of AlO _xN_4_-_x peaks was noticed, which was suggested to induced by slight dispersion of #alpha#-SiAlON ...
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 ...
A solid-state precipitation process was used to prepare superconducting tapes containing an A15 phase, V/sub 3/Ga or Nb/sub 3/Al, in a ductile niobium or vanadium containing BCC matrix. Ingots weighing as large as 30 to 50 gms of V-(14 approx. 19 at. %) Ga and Nb-(13 approx. 22 at. %) Al were prepared by arc-melting, homogenized, quenched, warm-rolled over 99% into tape, and aged at temperatures in the range 600/sup 0/C to 1000/sup 0/C to precipitate the superconducting A15 phase. The features demonstrated by the process are very attractive for practical applications. In the V-Ga system, transmission electron microscopy (TEM) studies revealed the A15 precipitates in an elongated form. However, for the Nb-Al samples, deformed and aged at 750/sup 0/C, TEM studies revealed A15 precipitation in fine equi-axed particles which formed as a semi-continuous network over sub-grain boundaries formed by the recovery of ...
Gas hydrates are crystalline substances composed of water and gas, in which a solid-water-lattice accommodates gas molecules in a cage-like structure. Gas hydrates are globally widespread in permafrost regions and beneath the sea in sediment of outer continental margins. While methane, propane, and other gases can be included in the clathrate structure, methane hydrates appear to be the most common in nature. The amount of methane sequestered in gas hydrates is probably enormous, but estimates are speculative and range over three orders of magnitude from about 100,000 to 270,000,000 trillion cubic feet. The amount of gas in the hydrate reservoirs of the world greedy exceeds the volume of known conventional gas reserves. Gas hydrates also represent a significant drilling and production hazard. A fundamental question linking gas hydrate resource and hazard issues is: What is the volume of gas hydrates and included gas within a given gas hydrate occurrence Most ...
Gas hydrates are crystalline substances composed of water and gas, in which a solid-water-lattice accommodates gas molecules in a cage-like structure. Gas hydrates are globally widespread in permafrost regions and beneath the sea in sediment of outer continental margins. While methane, propane, and other gases can be included in the clathrate structure, methane hydrates appear to be the most common in nature. The amount of methane sequestered in gas hydrates is probably enormous, but estimates are speculative and range over three orders of magnitude from about 100,000 to 270,000,000 trillion cubic feet. The amount of gas in the hydrate reservoirs of the world greedy exceeds the volume of known conventional gas reserves. Gas hydrates also represent a significant drilling and production hazard. A fundamental question linking gas hydrate resource and hazard issues is: What is the volume of gas hydrates and included gas within a given gas hydrate occurrence? Most ...
Methods currently being used or developed for the elemental analysis of materials are chemical analysis, non-destructive inspection and calorimetry. The chemical analysis, which removes high-level radioactive elements through chemical treatments and then performs the quantitative analysis using the ICP-MS(Inductively Coupled Plasma - Mass Spectrometer) or the ID-MS(Isotope Dilution Mass Spectrometer), is recognized the most accurate. However, it requires a long, complex pre-treatment process in which a mass spectrometer could be contaminated. To solve this problem, a new method, which can be performed with high-level radioactivity and at high temperature, was desired. Such a method should also have the same accuracy as the chemical analysis, with a less possibility for instruments to be contaminated. In addition, as interests in the environment and the life quality are increased, a detailed analysis on the environmental impacts is also required. Satisfying all of ...
A technique involving shifting of core fuel loadings was investigated as a method for reducing the neutron flux at points of high damage accumulation in the pressure vessel wall of a light water reactor. Calculations were run for six types of commercial generic PWR. Information is provided on the progress being made to develop and apply the Solid State Track Recorder (SSTR) method for in-situ in- and ex-vessel measurements of neutron exposure parameter values, such as fluence (E > 1.0 MeV) and dpa in iron. A new technique of quantitative track counting, the Buffon needle method, is advanced. It is based on random sampling of the SSTR surface. A desensitized etching technique was developed that resulted in an excellent differential energy response for alpha particles in the 3- to 14-MeV energy range. The optical efficiency of Muscovite mica for manual fission track counting is being redetermined to form a data base for comparison with ...
A necessary condition for crevice corrosion is that a crevice former create a sufficiently tight, restricted geometry on the metal surface to support the development of critical crevice chemistry. Crevice corrosion is affected by the crevice geometry (tightness) and the properties of the crevice former. The objective of this study is to determine the effect of the crevice former material on the evolution of localized corrosion-damage. A standard crevice corrosion test method is modified by (a) the use of ceramic, metal or polymer materials as the crevice former and (b) the variation of size and shape of the crevice. This study focuses on the post initiation stage of crevice corrosion and addresses factors that may limit the initiation of localized corrosion and also slow or stop the continued propagation of corrosion. Controlled crevice corrosion tests are performed under aggressive, accelerated conditions on Ni-Cr-Mo alloy C-22 and other alloys for comparison. Multiple techniques are ...
According to the LeChatelier-Braun principle, when a closed quiescent system initially in an equilibrium or unstressed steady state is subjected to an externally imposed ``stress'' it responds in a manner tending to alleviate that stress. Use of this entropically based qualitative rule, in combination with the notion of Maxwell thermal stresses existing in nonisothermal gases and liquids, enables one to (i) derive Maxwell's thermal-creep boundary condition prevailing at the boundary between a solid and a fluid (either gas or liquid) and (ii) rationalize the phenomenon of thermophoresis in liquids, for which, in contrast with the case of gases, an elementary explanation is currently lacking. These two objectives are achieved by quantitatively interpreting the heretofore qualitative LeChatelier-Braun notion of stress in the present context as being the fluid's stress tensor, the latter including Maxwell's thermal stress. In effect, thermophoretic ...
Lappeenranta University of Technology (LTKK) and VTT Energy carried out a series of preliminary tests in 1999 to study the behavior of noncondensable (NC) gases in VVER geometry. The tests aimed at studying the effect of NC gases on system thermal-hydraulics and on heat transfer in a horizontal steam generator (HSG). The system behavior can be affected by hydrogen produced in the core in case of a severe accident, by nitrogen from hydro-accumulators released into the primary circuit in case of a loss-of-coolant accident (LOCA) and more generally by any NC gas in all cases where cooling is ensured by natural circulation. A secondary objective of the tests - the first series of tests ever performed with NC gas with PACTEL - was to find out, if the instrumentation of PACTEL was adequate for this type of tests and if it was functioning properly. This paper presents the measured and calculated (CATHARE code version V15a mod 2.1) results of the test NCg-l. It was carried out in natural ...
Endothelial dysfunction and increased platelet aggregation may be involved in the pathogenesis of normal tissue radiation toxicity. This study assessed clopidogrel, an inhibitor of ADP-induced platelet aggregation, as a modulator of intestinal radiation injury (radiation enteropathy). Rat small intestine was exposed to 21 Gy X-radiation. Clopidogrel (20 mg/kg/day) or vehicle was administered from 2 days before to 10 days after irradiation. Structural radiation injury, neutrophil infiltration, smooth muscle cell proliferation, collagen content, and TGF-beta1 expression were assessed 2 weeks (early phase) and 26 weeks (delayed phase) after irradiation, using quantitative histology and immunohistochemistry, morphometry, and real-time fluorogenic probe RT-PCR. Irradiated intestine exhibited significant histopathologic injury, reduced mucosal surface area, vascular sclerosis, intestinal wall fibrosis, increased collagen content, ...
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 (AFM) on a single particle level after ...
Thermal energy storage performance of fatty acids and a eutectic mixture as phase change materials (PCMs) has been investigated experimentally. The selected PCMs for this study were palmitic acid, myristic acid, stearic acid, and a mixture of stearic and myristic acids in eutectic combination ratio of 65.7 wt% myristic acid and 34.3 wt% stearic acid. The PCMs have a melting temperature range of 50.0{sup o}C to 61.20{sup o}C and a latent heat range of 162.0 J/g to 204.5 J/g. The inlet temperature and the mass flow rate of heat transfer fluid (HTF) were selected as experimental parameters to test the thermal energy storage performance of the PCMs. The transition times, temperature range, propagation of the solid-liquid interface, as well as heat flow rate characteristics of the employed cylindrical tube storage system were studied at varied experimental parameters. The experimental results show that the melting front moves to inward in the radial ...
The nanocrystallization process of amorphous Fe_7_3_._5Si_1_3_._5B_9Nb_3Cu_1 was investigated by active screen plasma nitriding (ASPN) treatment at temperatures ranging from 410 "oC to 560 "oC for 3 h in two gas mixtures of 75% N_2-25% H_2 and 25% N_2-75% H_2 at 5 mbar atmosphere. The amorphous ribbons were then annealed under vacuum at the same time and temperatures mentioned above. The structure of the samples was analyzed using various techniques such as X-ray diffraction (XRD), atomic force microscopy (AFM) and differential scanning calorimetry (DSC). Microhardness measurements, electrical resistivity and Vibrating Sample Magnetometer (VSM) were used to study mechanical, electrical and magnetic properties of the samples, respectively. It was observed that the ASPN treatment leads to finer grain size and higher crystalline volume fraction and modifies the structural features of Fe(Si) phase. The Fe(Si) lattice parameter for the nitrided samples decreased up to ...
The information is reported on the kinetics of decomposition of weak hcp "3He-"4He solutions with the starting "3He concentration 0.5#+-#0.1% and 1.20#+-#0.2% under the sample pressure 3.5 to 3.8 MPa before the decomposition. The NMR technique of the prompt control of the phase separation process is developed. To accelerate the metastable phase decomposition, the samples were thermally cycled at temperatures below 100 mK. Using the pulse NMR method, the magnetic susceptibility of "3He nuclei and the spin-lattice T_1 and spin-spin T_2 relaxation times were measured on three samples of the decomposed solid solutions with the starting "3He concentration 0.5% at the pressures 3.53, 3.71 and 3.78 MPa. Above 10 mK the Curie-Weiss constant was two to three times higher than the values typical of bulk bcc "3He of the corresponding density. Below 10 mK the magnetic susceptibility was observed to deviate from the Curie-Weiss law. One ...
A numerical study has been performed to investigate the hydrodynamic aspects of the pool boiling on horizontal-, vertical- and downward-facing surfaces. The FlowLab code, which is based on a Lattice-Boltzmann (LB) model of two-phase flows, is employed. Macroscopic properties, such as surface tension ({sigma}) and contact angle ({beta}), are implemented through the fluid-fluid (G{sub {sigma}}) and fluid-solid (G{sub t}) interaction potentials. The model is found to express a linear relation between the macroscopic properties ({sigma}, {beta}) and microscopic parameters (G{sub {sigma}}, G{sub t}). The simulation results on bubble departure diameter appear to have the same parametric dependence as the empirical correlation. Hydrodynamic aspects of two-phase flow regime transition mechanism are investigated for different surface-coolant configurations. Results of the LB simulation clearly demonstrate that not only the bubble ...
For higher U-loading in low-enriched U-10 wt.%Mo fuels, monolithic fuel plate clad in AA6061 is being developed as a part of Reduced Enrichment for Research and Test Reactor (RERTR) program. This paper reports the first characterization results from a monolithic U-10 wt.%Mo fuel plate with a Zr diffusion barrier that was fabricated as part of a plate fabrication campaign for irradiation testing in the Advanced Test Reactor (ATR). Both scanning and transmission electron microscopy (SEM and TEM) were employed for analysis. At the interface between the Zr barrier and U-10 wt.%Mo, going from Zr to U(Mo), UZr_2, #gamma#-UZr, Zr solid-solution and Mo_2Zr phases were observed. The interface between AA6061 cladding and Zr barrier plate consisted of four layers, going from Al to Zr, (Al, Si)_2Zr, (Al, Si)Zr_3 (Al, Si)_3Zr, and AlSi_4Zr_5. Irradiation behavior of these intermetallic phases is discussed based on their constituents. ...
The objective of the current study was the gradual development of the formation of the nitride layer during inductive r.f. plasma nitriding. The study centers on characterization of refined layers and plasma diagnostics in the vicinity of the sample, and raises critical questions of how the layers and interfacial microstructure might affect the near-surface properties. The composition of the plasma near the surface of the sample (plasma layer) was examined by optical emission spectroscopy and mass spectrometry during plasma nitriding and while sputtering the sample after the nitriding process. It was observed that during the nitriding process, the plasma layer contains Ti, NH[sub n] species, N (or/and N[sup +]), H[sub n] species (or/and H[sup +][sub 2]). However, when the nitrided sample was exposed to argon plasma, Ti, Al and NH were observed. It was found that two distinct sublayers, comprising [delta]-TiN and [delta]-TiN + [epsilon]-Ti[sub 2]N phases, were ...
High voltage cathode materials Li-excess layered oxide compounds Li[Ni{sub x}Li{sub 1/3-2x/3}Mn{sub 2/3-x/3}]O{sub 2} (0 < x < 1/2) are investigated in a joint study combining both computational and experimental methods. The bulk and surface structures of pristine and cycled samples of Li[Ni{sub 1/5}Li{sub 1/5}Mn{sub 3/5}]O{sub 2} are characterized by synchrotron X-Ray diffraction together with aberration corrected Scanning Transmission Electron Microscopy (a-S/TEM). Electron Energy Loss Spectroscopy (EELS) is carried out to investigate the surface changes of the samples before/after electrochemical cycling. Combining first principles computational investigation with our experimental observations, a detailed lithium de-intercalation mechanism is proposed for this family of Li-excess layered oxides. The most striking characteristics in these high voltage high energy density cathode materials are (1) formation of tetrahedral lithium ions at voltage less than 4.45 V and (2) ...
Scanning electron microscopy and an electron-microprobe analysis of a sample of blast furnace (BF) coke have revealed alkalization (5.64 wt % Na{sub 2}O + K{sub 2}O) and Al saturation (17.28 wt % Al{sub 2}O{sub 3}) of SiO{sub 2} by BF gases. The K/Na{sub at} value of 1.15 in the new phase (alteration zone) reflects close atomic proportions of the elements and suggests that the abilities to incorporate K and Na during the process are almost equal. This Al saturation and alkalization of SiO{sub 2} indicates an active role for Al along with alkali metals in BF gases. The average width of the altered area in the SiO{sub 2} grain is about 10 m, which suggests that SiO{sub 2} particles of that size can be transformed fully to the new phase, provided that at least one of their faces is open to an external pore (surface of the coke) or internal pore with circulating BF gases. The grains that exceed 10 {mu}m can only be partly altered, which means that ...
OBJECTIVETo assess the new quantitative bone scan parameters as markers of Charcot neuroosteoarthropathy (CNO) activity.RESEARCH DESIGN AND METHODSForty-two...Full Text Available
Emphasis was put on the comparative quantitative structure-activity approaches to the exploration of action mechanisms of structurally different classes of compounds showing the same type of activity...Full Text Available
Effective small interfering RNA (siRNA)–mediated therapeutics require the siRNA to be delivered into the cellular RNA-induced silencing complex (RISC). Quantitative information of this essential...Full Text Available
A single radial hemolysis test was developed for quantitation of specific antibody to non-hemagglutinating viruses. With the human coronaviruses as models, this test utilizes the binding properties...Full Text Available
We have exploited ``progeny testing'' to map quantitative trait loci (QTL) underlying the genetic variation of milk production in a selected dairy cattle population. A total of 1,518 sires, with progeny...Full Text Available
Gene expression data has been used in lieu of phenotype in both classical and quantitative genetic settings. These two disciplines have separate approaches to measuring and interpreting epistasis, which...Full Text Available
Deficits in prepulse inhibition (PPI) are a biological marker for schizophrenia. To unravel the mechanisms that control PPI, we performed quantitative trait loci (QTL) analysis on 1,010 F2 mice derived...Full Text Available
The Electronic REference To access In vivo Concentrations (ERETIC) method was applied to 1H HR-MAS spectroscopy. The accuracy, precision, and stability of ERETIC as a quantitative...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
This document - IAEA Safeguards: Implementation Blueprint of Commercial Satellite Imagery - constitutes the second report from SSC Satellitbild giving a structured view and solid guidelines on how to proceed with a conceivable implementation of satellite imagery to support Safeguards activities of the Agency. This Phase 2 report presents a large number of concrete recommendations regarding suggested management issues, work organisation, imagery purchasing and team building. The study has also resulted in several lists of actions and preliminary project plans with GANT schedules concerning training, hardware and software, as well as for the initial pilot studies. In both the Phase 1 and Phase 2 studies it is confirmed that the proposed concept of a relatively small Imagery Unit using high-resolution data will be a sound and feasible undertaking. Such a unit capable of performing advanced image processing ...
In the framework of the search for a ceramic material usable in the radioactive waste storage, uranium and thorium phosphates have been investigated. Their experimental synthesis conditions have been entirely reviewed, they lead to the preparation of four new compounds: U(UO{sub 2})(PO{sub 4}){sub 2}, U{sub 2}O(PO{sub 4}){sub 2}, UCIPO{sub 4}, 4H{sub 2}O, and Th{sub 4}(PO{sub 4}){sub 4}P{sub 2}O{sub 7}. Experimental evidenced are advanced for non existent compounds such as: U{sub 3}(PO{sub 4}){sub 4}, U{sub 2}O{sub 3}P{sub 2}O{sub 7} and Th{sub 3} (PO{sub 4}){sub 4}. Characterization by several techniques (X-rays and neutron powder diffractions, UV-Visible and Infra-red spectroscopies, XPS,...) were performed. The ab initio structure determination of U(UO{sub 2})(PO{sub 4}){sub 2} has been achieved by X-rays and refined by neutron diffractions. Through its physico-chemical analysis, we found that this compound was a new mixed valence uranium phosphate in which U{sup 4+} and UO{sub ...
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 ...
Background:Solid pseudopapillary tumor is a rare pancreatic neoplasm with uncertain to low malignant potential. This is an uncommon neoplasm with many pseudonyms, occurring...Full Text Available
BackgroundCystic neoplasms of the pancreas are less common than solid tumors, and portend a better prognosis. They can be divided into serous and mucinous subtypes, with the former...Full Text Available
This program deals with solid waste disposal with topics/services covering: Reusable Building Materials and Large Household Items Exchange, Beneficial Use Determination, Biosolids, Certification, Compost Facil...
Investigation of the Macrokinetics and Energy of Self-Oscillatory Processes of Gasless Combustion of Solid Fuel Mixtures Proposed for the Design of Short-Term Thermal and Electrical Sources
May 31, 2011 ... A Theoretical Solid Oxide Fuel Cell Model for System Controls and Stability Design AUTHOR(S): Kopasakis, George; Brinson, Thomas; Credle, ...
We report the existence of a previously unsuspected peak in the [sup 1]H magic angle spinning spectrum of commercially available HZSM-5 samples. At 298 K, this resonance is a broad shoulder on the downfield side of the Bronsted acid signal at 4.3 ppm. Cooling the sample caused the line to narrow, and a clear peak at 6.9 ppm was visible at 123 K. This technique resulted in selective broadening of the 4.3 and 6.9 ppm resonances as a result of conflicting averaging of the [sup 1]H-[sup 27]Al dipolar coupling. We conclude that the 6.9 ppm resonance corresponds to a novel aluminum-containing site in zeolite HZSM-5 and is not an artifact due to exchange with the Bronsted site or an aluminum-rich impurity phase. A possible interpretation of these results is a second Bronsted site for the zeolite. 49 refs., 8 figs.
Electrical heating of subsea flowlines is an effective way to prevent wax and hydrate information, especially for long transportation distances and in low-temperature deep water. Systems are available for use in conjunction with bundles, pipe-in-pipe, and wet-thermal-insulation systems. These systems provide environmentally friendly fluid-temperature control without chemicals or flaring for pipeline depressurizing. Enhanced production is achieved because no time is lost by unnecessary depressurizing, pigging, heating-medium circulation, or removal of hydrate and wax blockages. The seabed temperature at 100-m and greater water depths may range from 7 to {minus}1.5 C, causing a rapid cooling of the hot well streams being transported in subsea flowlines. Under these supercooling conditions, vulnerable crude oils and multiphase compositions will deposit wax and asphalts; also the gas/water phase may freeze solid with hydrate particles. The paper ...
The equilibria composition of the gaseous and the solidphase in the system GeO/sub 2//WO/sub 2/ is calculated with an improved thermodynamical program for temperatures 1100 < T < 1400 K and constant volume. By means of the results the experimental observed migration of GeO/sub 2/ in the presence of WO/sub 2/ in a temperature gradient T/sub 2/ ..-->.. T/sub 1/ (1200 ..-->.. 1100 K) in sealed evacuated silica tubes is due to a chemical transport with H/sub 2/ as the transporting agent. The H/sub 2/ is formed by H/sub 2/O which is desorbed by the quartz glass of the ampoules. The also observed volatility of WO/sub 2/ and its deposition in form of Ge/sub 0.75/W/sub 3/O/sub 9/ at the 'cold' end (T/sub 1/) of the tubes is performed by gaseous GeWO/sub 4/. The calculated and experimental transport rates are compared and discussed.
In 1998, in the frame of the ITER EDA phase, an European R and D Programme for the Blanket Design was implemented for developing and selecting the materials and the relevant fabrication procedures for manufacturing the shielding modules of the ITER Primary Wall. The fabrication of several Beryllium armored small scale mock-ups, reproducing representative portions of a Primary Wall panels, was also launched (Fusion Technol. (1998) 195). Further experimental activities were also programmed for investigating the thermal-mechanical behavior of these mock-ups at high heat flux and under thermal fatigue tests. In 2001, the ITER European Home Team decided to assign to ENEA a contract for the thermal fatigue testing of six mock-ups aiming at verifying the reliability of the Beryllium/Dispersion Strengthened Copper alloy/Stainless Steel and Beryllium/Precipitation hardened Copper alloy/Stainless Steel joints manufactured by solid Hot Isostatic Pressing ...
Within the framework of a Dutch research program on the environmental effects of coal combustion 15 measuring campaigns were carried out in the eighties. All the relevant ingoing and outgoing flows of electric power plants were sampled and the heavy metals composition was determined. An overview is given of these fifteen measuring campaigns. It is concluded that between 99.7% and 99.9% of the fly ash can be separated by electrofilters. The removal of solid elements is higher than 99%, except for those elements, which are enriched in the fly ash, f.e. Cd and Se (>90% removal is possible). Additional separation of the emissions of fly ash and elements in the fly ash takes place in a flue gas desulfurization (FGD) installation. Some elements are emitted as gaseous wastes. After the electrofilter Cl, F and I can be found for almost 100%, Br and Hg for 50% on average, and only small amounts of As and Se in the gaseous phase. In a wet FGD unit ...
The leading challenge in the continued scaling of junctions made by ion implantation and annealing is the control of the undesired transient enhanced diffusion (TED) effect. Spike annealing has been used as a means to reduce this effect and has proven successful in previous nodes. The peak temperature in this process is typically 1050 deg. C and the time spent within 50 deg. C of the peak is of the order of 1.5 seconds. As technology advances along the future scaling roadmap, further reduction or elimination of the enhanced diffusion effect is necessary. We have shown that raising the peak temperature to 1175 deg. C or more and reduction of the anneal time at peak temperature to less than a millisecond is effective in eliminating enhanced diffusion. We show that it is possible to employ a sequence of millisecond anneal followed by spike anneal to obtain profiles that do not exhibit gradient degradation at the junction and have junction depth and sheet resistance appropriate to the ...
YIG precursor powder was obtained by homogeneous precipitation in chloride salt solution by thermal decomposition of urea. It was found that ferric ions precipitated prior to yttrium ions. The precipitate was minute and spherical in shape. The precipitate formed consisted of the mixture of amorphous and ferric oxyhydroxide. Crystallization of YIG was proceeded by solid state reaction of intermediate YFeO{sub 3} and Fe{sub 2}O{sub 3} in the temperature range of 850 deg. C to 1400 deg. C. Single phase of YIG was obtained by heat-treatment of the powder at 1400 deg. C for 6 hrs in air. The powder calcined was molded into pellets and sintered in air. The maximum density of 4.92 g/cm{sup 3} (95.1% of theoretical density) was obtainable for the pellet sintered at 1450 deg. C using the powder calcined at 900 deg. C. (author) 20 refs., 8 figs., 1 tab.
The paper discusses two petrochemical selective oxidation reactions namely the practised formation of styrene (STY) and the desired oxidative functionalisation of propane. The present knowledge about the mode of operation of oxide catalysts is critically considered. The dehydrogenation of ethylbenzene (EB) should be described by an oxidehydration with water acting as oxidant. The potential role of the coke formed during catalytic reaction as co-catalyst will be discussed. Selective oxidation is connected with the participation of lattice oxygen mechanism which transforms unselective gas phase oxygen into selective oxygen. The atomistic description of this process is still quite unclear as well as the electron structural properties of the activated oxygen atom. The Role of solid state acidity as compared to the role of lattice oxygen is much less well investigated modern multiphase-multielement oxide (MMO) catalysts. The rationale is that the ...
In 2001, EFDA has assigned to ENEA a contract for the thermomechanical testing of six mock-ups of the ITER primary wall module. These small scale mock-ups, reproducing representative portions of the reference ITER primary wall panels, were fabricated during ITER EDA phase by solid hot isostatic pressing (HIPping) of an AISI 316L stainless steel back structure to a alumina dispersion strengthened (DS)-Cu alloy heat sink armored with beryllium tiles. The experimental program, carried-out at ENEA Brasimone CEF 1-2 thermal hydraulic facility, was focused on the thermal mechanical testing of these mock-ups aiming at verifying which tile geometry and manufacturing procedure assures the required reliability of the beryllium/DS-Cu alloy/SS joints at high incident heat flux (>0.8 MW/m"2) both at steady state and under thermal fatigue tests. The paper presents the progress in the experimental activity of the first test campaign and the main ...
Fluorine is known to have a beneficial role for the B diffusion reduction in preamorphized Si, and is promising for the realization of ultra-shallow junctions. Thus, we studied the F incorporation in Si during the solidphase epitaxy (SPE) process, pointing out the effects of the implanted F energy and fluence and the role played by the possible presence of dopants. The incorporation of fluorine proceeds by F segregation at the amorphous-crystalline interface, with a kinetics driven by the SPE rate. In fact, the quicker the SPE rate, the higher is the F fluence retained. Moreover, we demonstrated that F incorporated in Si layers does not appreciably affect the Is emission from spatially separated end-of-range (EOR) defects. The modification, induced by the presence of F, of the point defect density (Is and Vs) was also studied by means of B and Sb spike layers, used as local markers for Is and Vs, respectively. We showed that F is not only able ...
Abstract Many (K1-xNax)NbO3 (KNN)-based ceramics with high piezoelectric performance exhibit undesirable strong temperature dependence due to the orthorhombic-tetragonal polymorphic phase transition near room temperature. In order to improve the temperature stability of the ceramics, many additives have been added into the KNN-based ceramics to shift TO-T down to below room temperature. Contrary to the previous approach (Na0.53K0.47-xAgx)Nb1-xSbxO3 (NKANS) ceramics with TO-T well above room temperature have been prepared by a conventional solid-state reaction method. The density and the electrical properties are effectively improved by the addition of AgSbO3, and optimum piezoelectric properties are found in the ceramics with 0.05---x---0.07, with maximum kp---0.46 for NKANS5 and maximum d...
Headspace solid-phase microextraction (HS-SPME) coupled to comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC-TOFMS) was applied for equilibrium headspace analysis of Malaysian soursop (Annona muricata) volatile flavor compounds. A two-level fractional factorial design (25-1) was used to determine the effect of SPME variables, namely, SPME fibers, adsorption temperature, extraction time, amount of salt, sample amount and sample concentration on the extraction efficiency of volatile flavor compounds. A total of 37 volatile compounds were identified, comprising 21 esters, 6 alcohols, 3 terpenes, 2 acids, 2 ketones, 2 aldehydes and an aromatic with different hydrophobicities (log P) ranging between -0.14 and 4.83. Extraction using 10g of diluted (5% w/w) ...
A method of kinetic analysis applicable to non-isothermal oxidation processes of ceramic nanocomposites is presented using Ti-Si-C-N powder as the substrate. The nanoparticle size and phase composition were determined using high-resolution transmission electron microscopy and X-ray diffraction (XRD). Thermogravimetric measurements were carried out for powder samples in dry air in the temperature range 298-1770 K. The following heating rates were applied: 3, 5, 10, 20 K min{sup -1}. Mass spectrometry was used to analyze gaseous oxidation products and solid products were identified by the XRD technique. The Coats-Redfern equation was applied for the kinetic analysis. For each stage of the oxidation kinetic models, the best accuracy was achieved using a series of criteria, and then the A and E parameters of the Arrhenius equations were estimated. Both linear regression and artificial neural networks were applied in testing kinetic models.
A number of agricultural and engineering uses for fixated flue gas desulfurization (FGD) material exist; however, the potential for leaching of hazardous elements has limited widespread application and the processes controlling the leaching of this material are poorly understood. In this study, a flow-through rotating-disk system was applied to elucidate the relative importance of bulk diffusion, pore diffusion, and surface chemical reaction in controlling the leaching of fixated FGD material under pH conditions ranging from 2.2 to 6.8. Changing the hydrodynamics in the rotating disk system did not affect the leaching kinetics at both pH 2.2 and 6.8, indicating that bulk diffusion was not the kinetic-limiting step. Application of the shrinking core model (SCM) to the data suggested a surface reaction-controlled mechanism, rather than a pore diffusion mechanism. The leaching of fixated FGD material increased with decreasing pH, suggesting it can be described by a combination of an ...
High-dose ion implantation followed by solid-phase-epitaxial (SPE) growth is now a well-established technique for the production of supersaturated silicon alloys. However, these alloys also contain a high supersaturation of silicon interstitials, which give rise to transient, greatly enhanced dopant diffusion with subsequent heating. In this contribution, the authors present a study of a series of Si-Sb alloys of various concentrations which were made by Sb implantation under various conditions to deduce the origin of the observed transient diffusion. A multiple implant scheme was employed to produce samples with an approximately uniform dopant concentration from 40 to 150 nm in depth, but with the amorphous layer extending to a depth of 380 nm. By scaling the implant doses, alloys with different concentrations in the uniform region were produced, allowing an accurate measure of diffusion coefficients as a function of concentration. Diffusion coefficients during ...
This paper presents a summary of the first phase of the EPA project, which encompasses surveys of residues from industrial sources in Alexandria. Studies to date indicate that wastes from various industries can be recovered economically. Wastes such as tin cans, glass, wastepaper, and food residues from processing of fruits, starch, and beer are examples of reusable industrial wastes in Egypt. The results of experimental studies for reuse of residues from oil refining, starch and yeast processing, and steel pickling are presented. Spent clay from edible oil refining is currently discarded, causing both handling and disposal problems. This clay contains as much as 40% oil; 90% can be recovered by extraction. The recovered oil can be successfully used in soap production, and the spent clay can be reused in oil bleaching. Other examples include starch and yeast wastes, which can be used for animal feed, and spent pickling liquor, which can be used as a coagulant aid ...
A scalar-relativistic procedure for calculating the valence-electron contribution to the total energy of bulk and thin-film solids has been developed and applied to the fcc and bcc phases of the group-VIB transition elements Cr, Mo, and W. This approach, which is based on the linear augmented-plane-wave method and local-density-functional theory, contains no shape approximations for either the charge density or potential. The formulation adopts a rigid-core approximation and incorporates an exact treatment of the core-charge tails that extend beyond the muffin-tin spheres. The application of this procedure to bcc Cr, Mo, and W yields calculated lattice parameters and bulk moduli that are in good (Cr) to excellent (Mo and W) agreement with experiment. The present calculated properties also agree quite well with the results of previous calculations involving a variety of band-structure methods. The calculated fcc-bcc energy difference for Cr, Mo, ...
In this paper, we present the results of Plasma-Enhanced Chemical Vapor Deposition gate-oxide (SiO_2) integrity on ELC (excimer-laser-crystallized), MILC (metal-induced lateral-crystallized) and SPC (solid-phase-crystallized) polysilicon films. We observed that gate oxide strength of poly-Si TFT strongly depends on the crystallization method for the active silicon layer. In the case of ELC films, asperities on the silicon surface reduce the SiO_2 breakdown field significantly. The metallic contaminants in MILC films are responsible for a deleterious impact on gate oxide integrity. Among the three cases, the SiO_2 breakdown field was the highest for the SPC silicon films. The breakdown fields at the 50 % failure points in Weibull plots for the ELC, MILC and SPC cases were 5.1 MV/cm, 6.2 MV/cm, and 8.1 MV/cm, respectively. We conclude that the roughness and metallic contamination of the poly-Si films are the main factors that cause enhanced breakdown of SiO_2 films.
High concentrations of self-interstitials are trapped by dopant atoms during ion implantation into Si. For group V dopants, these complexes are sufficiently stable to survive solid-phase-epitaxial (SPE) growth but break up on subsequent thermal processing and cause a transient-enhanced diffusion. Dopant diffusion coefficients are enhanced by up to five orders of magnitude over tracer values and are characterized by an activation energy of approximately one half of the tracer values. In the case of group III dopants, any complexes formed during implantation do not survive SPE growth but a second source of self-interstitials becomes significant and leads to similar transient effects. This is the damaged layer underlying the original amorphous/crystalline interface. These observations provide direct evidence for long-range self-interstitial migration in Si, and we believe these are the first observations of the interstitialcy diffusion mechanism with no vacancy ...
High concentrations of self-interstitials are trapped by dopant atoms during ion implantation into Si. For group V dopants, these complexes are sufficiently stable to survive solid-phase-epitaxial (SPE) growth but break up on subsequent thermal processing and cause a transient-enhanced diffusion. Dopant diffusion coefficients are enhanced by up to five orders of magnitude over tracer values and are characterized by an activation energy of approximately one half of the tracer values. In the case of group III dopants, any complexes formed during implantation do not survive SPE growth but a second source of self-interstitials becomes significant and leads to similar transient effects. This is the damaged layer underlying the original amorphous/crystalline interface. These observations provide direct evidence for long-range self-interstitial migration in Si, and we believe these are the first observations of the interstitialcy diffusion mechanism with no vacancy ...
In order to establish coal NOx preventive measures, discussions were given on formation of N2 in the fixed-bed pyrolysis of low rank coals and the mechanisms thereof. Chinese ZN coal and German RB coal were used for the discussions. Both coals do not produce N2 at 600{degree}C, and the main product is volatile nitrogen. Conversion into N2 does not depend on heating rates, but increases linearly with increasing temperature, and reaches 65% to 70% at 1200{degree}C. In contrast, char nitrogen decreases linearly with the temperature. More specifically, these phenomena suggest that the char nitrogen or its precursor is the major supply source of N2. When mineral substances are removed by using hydrochloric acid, their catalytic action is lost, and conversion into N2 decreases remarkably. Iron existing in ion-exchanged condition in low-rank coal is reduced and finely diffused into metallic iron particles. The particles react with heterocyclic nitrogen compounds and turn into iron nitride. A ...
Ho{sub 2}CuTiO{sub 6} double pervoskite is synthesized by solid state reaction method and the phase formation was confirmed by X-ray diffraction. Ho{sub 2}CuTiO{sub 6} crystallizes in space group P63 cm and are isostructural in AMnO{sub 3} structure. We have investigated the effect of the presence of a magnetic ion (Ho{sup 3+}{approx}10.4{mu}{sub B}) in Ho{sub 2}CuTiO{sub 6}, on the magnetic properties, compared to that of an isostructural double perovskite containing Y-ion (non-magnetic), i.e., Y{sub 2}CuTiO{sub 6}. Magnetization measurements on Ho{sub 2}CuTiO{sub 6} showed paramagnetic moment of 0.026{mu}{sub B}/Ho at room temperature in an applied field of 7 T although no saturation is observed at room temperature, whereas, at 5 K, the paramagnetic moment was 0.3{mu}{sub B}/Ho in the same field. Since this compound is non-centrosymmetric, it is of interest to look into the possibility of realizing multiferroicity (coexistence of magnetic and ...
Partially purified UDPgalactosyltransferase (EC 2.4.1.22) from bovine milk has been used to synthesize millimolar amounts of compounds such as Gal#beta#(1#->#4)Glc, Gal#beta#(1#->#4)GlcNAc-#beta#-hexanolamine, and Gal#beta#(1#->#4)-GlcNAc#beta#(1#->#4)GlcNAc. The same method has been used to prepare similar compounds containing "1"3C-enriched galactopyranosyl moieties. Gal#beta#(1#->#4)GlcNAc-#beta#-hexanolamine was also synthesized in a solid-phase system in which the GlcNAc-#beta#-hexanolamine glycoside was covalently linked to agarose beads. At pH 7.0 and at 1 to 5 mM Mn"2"+"+ the yields of the galactosyl saccharides are greater than 90% by using 10% excess of UDPGal donor. The use of a 90% enriched [1-"1"3C]galactosyl residue allowed the determination of the most abundant conformer about the galactopyranosyl-glycoside linkage by analysis of the carbon-carbon coupling constants from Cl to Gal to the C3', C4', and C5' of GlcNAc or Glc. 3 figures, 1 ...
BaxSr1-xTiO3 (x=0.6, 0.75, 0.80, 0.85 and 0.9) compositions are prepared by solid-state reaction route using controlled heating and cooling. Density optimization by varying sintering temperature was achieved. X-ray diffraction (XRD) analysis shows the phase pure materials. The lattice constant decreases from 3.9868A (x=0.90) to 3.9449A (x=0.60) with increasing Sr2+; the tetragonal distortion also decreases. Dielectric constant show sharp peaks for samples having low strontium content (0.10, 0.15) and gets smeared out as the strontium content is increased (0.20, 0.25). For further higher Sr2+ composition (0.40), the dielectric peak could not be observed in the measured temperature range. The peak broadening in Sr2+ rich compositions indicates that diffused transitions and is attributed to t...
Phosphor material BaAl2O4:Eu2+, Dy3+ with varying compositions of Sr substitution were prepared by the solid-state synthesis method. The phosphor compositions were characterized for their phase and crystallinity by XRD, SEM and TEM. Photoluminescence (PL) properties were investigated measuring PL and decay time for varying Ba/Sr compositions. The PL results show the blue shift in the luminescence properties in Sr substituted BaAl2O4:Eu2+, Dy3+ compared to parent BaAl2O4:Eu2+, Dy3+. It is probably due to the influence of 5d electron states of Eu2+ in the crystal field because of atomic size variation causing crystal defects. Dy3+ ion doping in the phosphor generates deep traps, which results in long afterglow phosphorescence.
Holmium doped barium based hexaferrites BaFe12-2xHo2xO19 with (x=0.0-1.0) were synthesized by solid state reaction method. Structural and magnetic characterization of these ferrites provide significant information about their reactive physical properties. X-ray analysis reveals that in all samples M-type structure exist with few secondary phases. Scanning electron microscope revealed the grain size of the specimen. The results show that grain size decreases with the substitution degree of Holmium. Thus rare earth element Holmium Ho^3^+ acts as a grain growth inhibitor. The magnetic hysteresis loops show the variation in the values of magnetic parameters like saturation magnetization (Ms), remanent magnetization (Mr) and coercivity (Hc) were observed by changing Ho^3^+ content in BaFe12-2xH...
Holmium doped barium based hexaferrites BaFe_1_2_-_2_xHo_2_xO_1_9 with (x = 0.0-1.0) were synthesized by solid state reaction method. Structural and magnetic characterization of these ferrites provide significant information about their reactive physical properties. X-ray analysis reveals that in all samples M-type structure exist with few secondary phases. Scanning electron microscope revealed the grain size of the specimen. The results show that grain size decreases with the substitution degree of Holmium. Thus rare earth element Holmium Ho"3"+ acts as a grain growth inhibitor. The magnetic hysteresis loops show the variation in the values of magnetic parameters like saturation magnetization (M_s), remanent magnetization (M_r) and coercivity (H_c) were observed by changing Ho"3"+ content in BaFe_1_2_-_2_xHo_2_xO_1_9 ferrites. Coercivity showed a maximum value of 2230 Oe for (x = 0.4) and then decreasing trend were observed in the values of ...
A method was developed for the determination of plutonium in the soil samples by ICP-MS with TOA extraction chromatographic column. The optimized sample loading rate is below 0.2 mL/min (column inner diameter is 3.5 mm). Using hot 0.02 mol/L oxalic acid (H_2C_2O_4) in 0.16 mol/L HNO_3 to elute Pu from the solidphase in the column. The Pu recovery of 87.3%-96.8% in soil samples was obtained. The plutonium is separated with the ion exchange method in this work. Both extraction chroma- tography and ion-exchange methods efficiently remove the uranium and matrix interference from the ICP- MS measurement. The instrumental detection limit for "2"3"9Pu was 0.48 pg/mL, which corresponds to 1, 1 mBq/mL. (authors)
The determination of the banned anabolic substance zeranol and the metabolites taleranol and zearalanone in bovine urine is complicated by the occurrence of the structurally-related mycotoxin zearalenone and the corresponding {alpha}- and {beta}-zearalenol metabolites which possess similar estrogenic properties. A liquid chromatography-negative ion electrospray tandem mass spectrometric method is presented for the confirmatory analysis of all six resorcylic acid lactones ('zeranols') in urine samples using deuterium-labelled internal standards. The method was validated as a confirmatory method for bovine urine samples according to new draft EU guidelines and showed good precision and linearity, and CC{alpha} and CC{beta} values of 0.02-0.30 and <1.0 ng ml{sup -1}, respectively. The applicability was demonstrated by comparing the results of an incurred sample with previous results on the same sample obtained by gas chromatography high resolution mass ...
This paper reports that the co-deposition of chromium and silicon into a 2.25Cr-1.0Mo-0.15C steel, alloy 800, and type 304 stainless steel has been achieved using the pack cementation process. The ferritic coating produced on the 2.25 Cr-1.0Mo steel was approximately 225 {mu}m (9 mils) thick, whereas the inward diffusion of chromium and silicon produced a two-phase structure of ferrite and austenite for type 304. Chromium and silicon were incorporated into the austenitic solid solution upon diffusion into alloy 800. All coatings had approximately 25 to 35 wt% Cr and 2 to 3% Si at the surface. Cyclic oxidation testing in air of the coated 2.25Cr-1.0Mo steel (T = 700{degrees} C) and type 304 (T = 1035{degrees} C) showed a dramatic decrease in the oxidation kinetics compared to the original uncoated alloys. The cyclic oxidation of alloy 800 was also improved.
In this study, perovskite type oxide YAlO_3 has been doped with different amounts of the divalent cation Ca to synthesize Y_1_-_xCa_xAlO_3_-_#delta# (x = 0-0.21) compositions. The effect of dopant concentration on the crystal structure and electrical properties of YAlO_3 synthesized by citrate gel route has been investigated. The phase purity of the samples has been carried out using X-ray diffraction. The microstructural evaluation of the samples has been conducted by scanning electron microscopy and energy dispersive spectrum analysis. Thermal analysis has been conducted to monitor the decomposition of the intermediate products. The electrical conductivity studies have been performed using a.c. impedance spectroscopy as a function of temperature in the range 200-800 "oC in air. The Y_0_._9_4Ca_0_._0_6AlO_3_-_#delta# composition exhibits a total conductivity of 2.5 mS/cm at 800 "oC.
A comprehensive and highly selective method for detecting in bacterial supernatants a modified sulfur nucleoside, S-adenosyl-L-methionine (SAM), and its metabolites, i.e., S-adenosylhomocysteine (SAH), adenosine (Ado), 5prime-deoxy-5prime-methylthioadenosine (MTA), adenine (Ade), S-adenosyl-methioninamine (dcSAM), homocysteine (Hcy) and methionine (Met), was developed. The method is based on reversed-phase liquid chromatography with positive electrospray ionization (ESI+) coupled to a hybrid linear quadrupole ion trap (LTQ) and 7-T Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). A gradient elution was employed with a binary solvent of 0.05 M ammonium formate at pH 4 and acetonitrile. The assay involves a simultaneous cleanup of cell-free bacterial broths by solid-pha...
There has been a good deal of interest in the sialon system of ceramics in recent years due to their combination of important engineering properties #beta# including strength, hardness, low thermal expansion and good thermal shock resistance. #beta#-sialon (Si_6_-_zAl_zO_zN_8_-_z ;0solid state Nuclear Magnetic Resonance techniques in determining the nature of intermediate phases which occur. 9 refs., 1 tab., 1 fig.
This second report covers the period August 1 to September 30, 1991. During this period we modified our approach to Task 1 (Hybrid Armature study) with the addition of a numerical simulation of the steady state plasma brush length with a 1-D, four-phase equation of state code. A test fixture was designed and fabrication begun on a plasma brush test fixture for hybrid studies. It will be powered by a 140 kJ, 1 MA capacitor bank on loan to the project. Diagnostic data collection with 20 channels of digitizers and data reduction with a microvax were also arranged. Sliding friction of a solid armature was simulated and found to form a vapor layer at velocities below 2 km/s. The simulations indicated that higher interface pressure results in vapor boundary layer formation at lower velocity. If there is also a minimum interface pressure required to commutate high currents, then an optimum interface pressure will probably result. Plans for a launcher ...
Mixed-conducting ceramic oxides have potential uses in high-temperature electrochemical applications such as solid oxide fuel cells, advanced batteries, sensors, and oxygen-permeable membranes. The Sr-Fe-Co-O system combines high electronic/ionic conductivity with appreciable oxygen permeability at elevated temperatures. Dense ceramic membranes made of this material can be used to separate high-purity oxygen from air without the need for external electrical circuitry, or to partially oxidize methane to produce syngas. Samples of Sr{sub 2}Fe{sub 3{minus}x}Co{sub x}O{sub y} (with x = 0, 0.6, 1.0, and 1.4) were prepared by solid-state reaction in atmospheres with various oxygen partial pressures (pO{sub 2}) and were characterized by X-ray diffraction, scanning electron microscopy, and electrical conductivity measurements. Phase components of the samples are dependent on cobalt concentration and synthesis pO{sub 2}. Total ...
The follow-up system for wastes (JAeSTI), developed at the end of the 1990s, forms a basis for today's followup activities in Finland. JAeSTI relies on an environmental protection database, the compliance monitoring system VAHTI operated by the environmental authorities. Waste followup and waste statistics depend very much on the annual waste quantities recorded in the VAHTI system. In the KYJ-project the coverage and reliability of the data in the VAHTI system was evaluated as for the streams of solid municipal waste. The project also included the compiling of national statistics on municipal waste for the year 2000. The project used other information sources, too, such as statistics compiled when the National Waste Plan and regional waste plans were revised in 2002. In addition, the extent and quantity of in-situ (household) composting and incineration were assessed on the basis of a separate study (Annex 2, In Finnish). In connection with the data ...
The aim of this work is to simulate the reduction by hydrogen of the tri-uranium octo-oxide U{sub 3}O{sub 8} (obtained by uranium trioxide calcination) into uranium dioxide. The kinetics curves have been obtained by thermal gravimetric analysis, the hydrogen and steam pressures being defined. The geometrical modeling which has allowed to explain the trend of the kinetics curves and of the velocity curves is an anisotropic germination-growth modeling. The powder is supposed to be formed of spherical grains with the same radius. The germs of the new UO{sub 2} phase appear at the surface of the U{sub 3}O{sub 8} grains with a specific germination frequency. The growth reactivity is anisotropic and is very large in the tangential direction to the grains surface. Then, the uranium dioxide growths inside the grain and the limiting step is the grain surface. The variations of the growth reactivity and of the germination specific frequency in terms of the gases partial ...
This paper discusses a new type of supramolecular material tris{5-N-[3-(9H-carbazol-9-yl)propyl]-N-(4-methylphenyl) aminesulfonyl-8-hydroxyquinolato} aluminum(III), Al(SCarq)3, which we synthesized using three 5-N-[3-(9H-carbazol-9-yl)propyl]-N-(4-methylphenyl) aminesulfonyl-8-hydroxyquinoline as bidentate ligands. The peak photoluminescence in the solidphase appears at 488 nm. In cyclic voltammetric measurement, two oxidation peaks, which were obtained at -5.6 and -5.9 eV, correspond to HOMO sites of carbazoyl and aluminum quinolates, respectively. In the investigation of solid morphological thin film, the flat surface was investigated using an atomic force microscope. The root mean square (rms) and mean roughness (Ra) were respectively measured to be 0.427 and 0.343 nm. For the fabrication of organic light-emitting devices (OLEDs) using spin-coating techniques, the turn-on voltage and maximum luminescence of the ...
A copyrighted computational fluid dynamics computer code, ICOMFLO, has been developed for the simulation of multiphase reacting flows. The code solves conservation equations for gaseous species and droplets (or solid particles) of various sizes. General conservation laws, expressed by elliptic type partial differential equations, are used in conjunction with rate equations governing the mass, momentum, enthalpy, species, turbulent kinetic energy, and turbulent dissipation. Associated phenomenological submodels of the code include integral combustion, two parameter turbulence, particle evaporation, and interfacial submodels. A newly developed integral combustion submodel replacing an Arrhenius type differential reaction submodel has been implemented to improve numerical convergence and enhance numerical stability. A two parameter turbulence submodel is modified for both gas and solidphases. An evaporation submodel treats ...
Single-phased Sr3B2SiO8:Eu3+ phosphor was prepared by a solid-state method at 1020 oC. The luminescence spectra showed that Sr3B2SiO8:Eu3+ phosphor can be effectively excited by near ultraviolet light (393 nm) and blue light (464 nm). When excited at 393 or 464 nm Sr3B2SiO8:Eu3+ exhibited the main emission peaks at 611 and 620 nm, which resulted from the supersensitive 5D0#->#7F2 transition of Eu3+. The luminescence intensity of Sr3B2SiO8:Eu3+ at 611 and 620 nm reached the maximum when the doping content of Eu3+ was 4.5 mol%. Its chromaticity coordinates (0.646, 0.354) were very close to the NTSC standard values (0.67, 0.33). Thus, Sr3B2SiO8:Eu3+ is considered to be an efficient red-emitting phosphor for long-UV InGaN-based light-emitting diodes. - Highlights: ? Sr3B2SiO8:Eu3+ was synthesized using solid-state reaction method for the first time. ? The phosphor can be efficiently excited by the near-UV chips and gives ...
The contaminants that are potentially present in the coal-derived gas stream and their thermochemical nature are discussed. Accelerated testing was carried out on Ni-YSZ/YSZ/LSM solid oxide fuel cells (YSZ: yttria stabilized zirconia and LSM: lanthanum strontium manganese oxide) for eight main kind of contaminants: CH{sub 3}Cl, HCl, As, P, Zn, Hg, Cd and Sb at the temperature range of 750-850 C. The As and P species, at 10 and 35 ppm, respectively, resulted in severe power density degradation at temperatures 800 C and below. SEM and EDX analysis indicated that As attacked the Ni region of the anode surface and the Ni current collector, caused the break of the current collector and the eventual cell failure at 800 C. The phosphorous containing species were found in the bulk of the anode, they were segregated and formed ''grain boundary'' like phases separating large Ni patches. These species are presumably ...
This project proposes to design and develop a new class of power converters (direct DC to AC) to drastically improve performance and optimize the cost, size, weight and volume of the DC to AC converter in SOFC systems. The proposed topologies employ a high frequency link; direct DC to AC conversion approach. The direct DC to AC conversion approach is more efficient and operates without an intermediate dc-link stage. The absence of the dc-link, results in the elimination of bulky, aluminum electrolytic capacitors, which in turn leads to a reduction in the cost, volume, size and weight of the power electronic converter. The feasibility of two direct DC to AC converter topologies and their suitability to meet SECA objectives will be investigated. Laboratory proto-type converters (3-5kW) will be designed and tested in Phase-1. A detailed design trade-off study along with the test results will be available in the form of a report for the evaluation of SECA Industrial ...
Mesporous anatase-phase TiO(2) hollow spheres with high photocatalytic activity were prepared by hydrothermal treatment and self-transformation of amorphous TiO(2) solid spheres in an NH(4)F aqueous solution. The prepared samples were characterized by X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, N(2) adsorption-desorption isotherms and UV-vis absorption spectroscopy. The photocatalytic activity was evaluated by photocatalytic oxidation decomposition of acetone in air under UV irradiation. It is found that F(-) plays an essential role in the formation of TiO(2) hollow spheres. F(-) not only induces the hollowing of TiO(2) solid spheres, but also promotes the crystallization of anatase TiO(2) nanocrystals. A possible formation mechanism for the TiO(2) hollow spheres by localized Ostwald ripening or chemically induced self-transformation is proposed based on the ...
Since the beginning of the sixties, France has developed a fleet of nuclear powered vessels. Insofar as the ships of the 2. generation are being built, the older ones are decommissioned and enter the dismantling process. The average rate is presently one submarine decommissioned every two or three years. The overall strategy for the decommissioning of French nuclear submarines can be brought down to 3 phases: 1. Level 1 dismantling which essentially consists in: - unloading the spent fuel and storing it in a pool ; - possibly emptying the circuits which contain radioactive liquids. The level 1 is easily achieved, as it is not very different from the plant situation during ship overhaul or major refits. 2. Level 2 dismantling which consists in isolating the nuclear reactor compartment from the rest of the submarine and conditioning it for interim storage on a ground facility located inside Cherbourg Naval Dockyard. The rest of the ship is decontaminated, controlled ...
The population growth, changing consumption patterns, and rapid urbanization contribute significantly to the growing volumes of solid waste that are generated in urban settings. As the rate of urbanization increases, demand on the services of solid waste management increases. The rapid urban growth in Langkawi Island, Malaysia, combined with the increasing rates of solid waste production has provided evidence that the traditional solid waste management practices, particularly the methods of waste collection and disposal, are inefficient and quite nonsustainable. Accordingly, municipal managers and planners in Langkawi need to look for and ...
Polychlorinated dibenzo-p-dioxins and dibenzo-furans form a family of more than 200 compounds which are relatively stable in the biosphere and tend to accumulate in the human body. The tetra- to hexa-chlorinated dioxins and furans are considered highly toxic. To facilitate the assessment of the total toxicity of dioxin and furan mixtures, the estimated toxic effects of the individual compounds relative to the 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) were introduced as Toxic Equivalent Factors which yield, when multiplied with the respective concentrations, the Toxic Equivalent (TE) of the mixture. Toxic dioxins and furans are unintentionally formed in a number of industrial combustion processes such as waste incineration and iron ore sintering, in the chemical industry and in household heating. To keep the emissions as low as possible, off-gas clearing systems for the collection of dioxins and furans are increasingly prescribed by the authorities. In addition, it appears desirable ...
A solid pseudopapillary tumor is an uncommon tumor of the pancreas that rarely metastasizes to other organs and usually shows good prognosis. An extrapancreatic tumor arising from a solid pseudopapillary tumor is very rare. We report a case of an atypical extrapancreatic solid pseudopapillary tumor that arose from the great omentum and disseminated to the peritoneum, and discuss the radiologic findings, including the CT, US, and MRI.
A solid pseudopapillary tumor is an uncommon tumor of the pancreas that rarely metastasizes to other organs and usually shows good prognosis. An extrapancreatic tumor arising from a solid pseudopapillary tumor is very rare. We report a case of an atypical extrapancreatic solid pseudopapillary tumor that arose from the great omentum and disseminated to the peritoneum, and discuss the radiologic findings, including the CT, US, and MRI
Research investigating applicability of lithium salts for solid electrolyte batteries was described. The studies included determinations of lithium ion conductivities in solid electrolyte systems based on Li4SiO4, LiTi2(PO4)3, and ceramic materials. Research on all solid state lithium cells utilizing TiS2 NiPS3 electrodes was also reported.
Solids are separated from a liquid in a gravity settler provided with inclined solid intercepting surfaces to intercept the solid settling path to coalesce the solids and increase the settling rate. The intercepting surfaces are inverted V-shaped plates, each formed from first and second downwardly inclined upwardly curved intersecting conical sections having their apices at the vessel wall.
Abstract Uniformly distributing slurry solids in -tall- (-2:1 aspect ratio) process vessels is a significant challenge in the chemical industry. This work determined the performance of various multi-tier agitation systems in uniformly distributing a settling solid throughout water in a -tall- laboratory vessel. It used a 0.445-m ID Plexiglas tank, with a slurry height of 0.889-m, to determine how solids distribution changes with solids loading (wt.%), impeller speed, and impeller type. Some impeller types uniformly distributed the solids even before energy input exceeded 1.00-W/kg. Significantly higher energy improved solids distribution little because flow within the vessel eventually became choked.
Cementitious materials provide an ideal geochemical environment (e.g., high pH pore fluids and large surface areas for sorption) for immobilizing nuclear waste. The inclusion of reducing agents, such as blast furnace slag (BFS) can immobilize radionuclides by forming of solid sulfide phases. Thermodynamic calculations using the MINTEQ geochemical computer code indicate the elemental sulfur present in BPS reacts with the highly mobile pertechnetate anion (TcO{sub 4}{sup -}) anion to form an insoluble technetium sulfide phase (Tc{sub 2}S{sub 7(s)}). Initially, the waste form very effectively immobilizes technetium. However, as oxygen diffuses into the waste form, an outer zone of oxidized concrete and a shrinking core of reduced intact concrete develops. Oxidation of sulfur in the outer zone results in increased technetium concentrations in the pore fluid because Tc{sub 2}S{sub 7(a)} oxidizes to the mobile TcO{sub 4}{sup -} ...
Both solvent extraction and spectrophotometric techniques were used to show the alterations that gamma radiation causes in the behavior of tetracycline molecule as far as its extracting and complexing power are concerned. The effect of gamma radiation on the solid tetracycline molecule, benzyl alcohol and on the solution of both was examined in solvent extraction systems whose aqueous phases were made up by {sup 152} Eu-{sup 154}Eu radioactive tracer solutions and whose organic phases were constituted by tetracycline-benzyl alcohol solutions. Experiments were performed in order to determine whether or not the water used for the pre-saturation of benzyl alcohol would influence the radiolysis of tetracycline. Solvent extraction and spectrophotometry were the techniques used to obtain the necessary data. Absorption spectra of irradiated tetracycline benzyl alcohol solutions submitted to several gamma radiation doses were ...
Full text: It was recently-established for hexagonal barium ferrite-industrially important magnetically hard material that refinement of the crystallite dimensions into the nanoscale regime, typically #<=# 10 nm, leads after heat treatment at temperatures 800-1000 deg C to significant coercivity increase of up to 6.5 kOe (#approx#3-4 times) with saturation magnetisation values of 50-55 emu/g (#approx#95% of bulk at room temperature). High-energy mechanochemical processing has been applied to prepare nanostructural (nanocrystalline-amorphous) composites. High resolution electron microscopy studies reveal that the enhancement of the final magnetic properties was due to formation of magnetically noninteracting #approx#l,#mu#m Ba-ferrite particles with 5-10 nm amorphous surface layer - depending on annealing parameters. Similar situation was established also for ball milled strontium ferrite (SrFe_1_2O_1_9) powders where short annealing 4 h at 1000 deg C produced increased H_c value of ...
Single crystals of Li{sub 1.8}(In{sub 0.55}Zr{sub 0.45}){sub 2}(PO{sub 4}){sub 3} and Li{sub 3}(In{sub 1-x}Sc{sub x}){sub 2}(PO{sub 4}){sub 3} (x=0.67,0.73) were grown by a flux method. The crystal structure of Li{sub 1.8}(In{sub 0.55}Zr{sub 0.45}){sub 2}(PO{sub 4}){sub 3} was found to be similar to that of the high temperature {gamma}-phase of Li{sub 3}Sc{sub 2}(PO{sub 4}){sub 3}. However, Li ions were located on only one site among three available sites. On the other hand, those of Li{sub 3}In{sub 2}(PO{sub 4}){sub 3}-Li{sub 3}Sc{sub 2}(PO{sub 4}){sub 3} solid solutions were found to be similar to that of the low temperature {alpha}-phase of Li{sub 3}Sc{sub 2}(PO{sub 4}){sub 3}. The ionic conductivity of Li{sub 1.8}(In{sub 0.55}Sc{sub 0.45}){sub 2}(PO{sub 4}){sub 3} was measured along with the directions perpendicular and parallel to the a-axis. A relatively large anisotropic conductivity was observed in the single ...
Exploratory experiments of laser welding cast Ni-based superalloy K418 turbo disk and alloy steel 42CrMo shaft were conducted. Microstructure of the welded seam was characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive spectrometer (EDS). Mechanical properties of the welded seam were evaluated by microhardness and tensile strength testing. The corresponding mechanisms were discussed in detail. Results showed that the laser-welded seam had non-equilibrium solidified microstructures consisting of FeCr{sub 0.29}Ni{sub 0.16}C{sub 0.06} austenite solid solution dendrites as the dominant and some fine and dispersed Ni{sub 3}Al {gamma}' phase and Laves particles as well as little amount of MC short stick or particle-like carbides distributed in the interdendritic regions. The average microhardness of the welded seam was relatively uniform and lower than that of the base metal ...
Exploratory experiments of laser welding cast Ni-based superalloy K418 turbo disk and alloy steel 42CrMo shaft were conducted. Microstructure of the welded seam was characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive spectrometer (EDS). Mechanical properties of the welded seam were evaluated by microhardness and tensile strength testing. The corresponding mechanisms were discussed in detail. Results showed that the laser-welded seam had non-equilibrium solidified microstructures consisting of FeCr_0_._2_9Ni_0_._1_6C_0_._0_6 austenite solid solution dendrites as the dominant and some fine and dispersed Ni_3Al #gamma#' phase and Laves particles as well as little amount of MC short stick or particle-like carbides distributed in the interdendritic regions. The average microhardness of the welded seam was relatively uniform and lower than that of the base metal due to partial ...
The U.S. Geological Survey, in cooperation with the U.S. Department of Energy, is conducting a study to determine the natural geochemistry of the Snake River Plain aquifer system at the Idaho National Engineering Laboratory (INEL), Idaho. As part of this study, a group of geochemical reactions that partially control the natural chemistry of ground water at the INEL were identified. Mineralogy of the aquifer matrix was determined using X-ray diffraction and thin-section analysis and theoretical stabilities of the minerals were used to identify potential solid-phase reactants and products of the reactions. The reactants and products that have an important contribution to the natural geochemistry include labradorite, olivine, pyroxene, smectite, calcite, ferric oxyhydroxide, and several silica phases. To further identify the reactions, analyses of 22 representative water samples from sites tapping the Snake River Plain aquifer system were used to ...
The reaction of uranium oxides and chlorine to prepare anhydrous uranium tetrachloride (UCl{sub 4}) are important to more economical preparation of uranium metal. The most practical reactions require carbon or carbon monoxide (CO) to give CO or carbon dioxide (CO{sub 2}) as waste gases. The chemistry of U-O-Cl compounds is very complex with valances of 3, 4, 5, and 6 and with stable oxychlorides. Literature was reviewed to collect thermochemical data, phase equilibrium information, and results of experimental studies. Calculations using thermodynamic data can identify the probable reactions, but the results are uncertain. All the U-O-Cl compounds have large free energies of formation and the calculations give uncertain small differences of large numbers. The phase diagram for UCl{sub 4}-UO{sub 2} shows a reaction to form uranium oxychloride (UOCl{sub 2}) that has a good solubility in molten UCl{sub 4}. This appears more favorable to good rates ...
Intermetallic compounds based on the Al-Co system were synthesized by solid state method - mechanical alloying and their properties were investigated using XRD, SEM, and DSC. The powder was used to make new targets of irradiation for gamma sources in order to enhance the specific activity and to reduce the consumption of material. The intermetallic compound AlCo was formed in the first 4 hours of milling. After 8 hours of milling the medium size of crystallites were of 5.58 nm. This value decreases with the increase of milling time up to 3 nm, corresponding to the 28 hours of grinding. There was calculated and plotted the Gibbs function, #DELTA#_f"0, for the reaction of formation AlCo and Al_3Co from the Al-Co system. It had negative values over the entire range of temperatures for both investigated compounds. After 28 hours milling a phase composition was obtained as follows: 0.2% Al; 21%Co ; 55.5%AlCo; 23.3% Al_1_3Co_4. AlCo 98% has been ...
The micro-arrangement of hydrogen atoms and the electronic properties of hydrides LaNi_5H_x (0.5, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0) have been systematically investigated by means of the density functional theory using the full-potential linearized augmented plane wave (FLAPW) method with the generalized gradient approximation (GGA). The calculated results indicate that H atoms prefer to occupy the 12n site in the #alpha# solid solution phase. For the #beta# phase, once the first H atom locates in the basal plane (12n site), and because it is difficult for the second H atom to still locate in the 12n site, the second H atom would prefer to occupy the middle plane site (6m site). When the number of H atoms increases from 3 to 5, they would occupy the other 12n and 6m sites by turns. Furthermore, our optimized data indicate that the structures P3 and P63mc are the most favorable structures of LaNi_5H_6 and LaNi_5H_7, ...
In this paper, we evaluate the performance of the 1- and 5-site models of methane on the description of adsorption on graphite surfaces and in graphitic slit pores. These models have been known to perform well in the description of the fluid-phase behavior and vapor-liquid equilibria. Their performance in adsorption is evaluated in this work for nonporous graphitized thermal carbon black, and simulation results are compared with the experimental data of Avgul and Kiselev (Chemistry and Physics of Carbon; Dekker: New York, 1970; Vol. 6, p 1). On this nonporous surface, it is found that these models perform as well on isotherms at various temperatures as they do on the experimental isosteric heat for adsorption on a graphite surface. They are then tested for their performance in predicting the adsorption isotherms in graphitic slit pores, in which we would like to explore the effect of confinement on the molecule packing. Pore widths of 10 and 20 A are chosen in this ...
Richmond Harbor is on the eastern shoreline of central San Francisco Bay and its access channels and several of the shipping berths are no longer wide or deep enough to accommodate modem deeper-draft vessels. The Water Resources Development Act of 1986 (PL99-662) authorized the US Army Corps of Engineers (USACE), San Francisco District to deepen and widen the navigation channels in Richmond Harbor. Several options for disposal of the material from this dredging project are under consideration by USACE: disposal within San Francisco Bay, at open-ocean disposal sites, or at uplands disposal sites. Purpose of this study was to conduct comprehensive evaluations, including chemical, biological, and bioaccumulation testing of sediments in selected areas of Richmond Harbor. This information was required by the Environmental Protection Agency (EPA) and USACE. Battelle/Marine Sciences Laboratory collected 20 core samples, both 4-in. and 12-in., to a project depth of -40 ft mean lower low water ...
Film boiling is the mode if boiling during which the hot surface is separated from the vaporizing liquid by a nearly continuous film vapor. Film boiling is usually considered a very undesirable boiling regime since it is a relatively quiet and inefficient mode of heat transfer, particularly as compared to nucleate boiling. It is customary to analyze the two-phase flow regime of laminar flow film boiling by assuming the two-phase flow regime of laminar flow film boiling by assuming an idealized vapor film flow characterized by a smooth liquid-vapor interface. However, during stable flow film boiling, the wavy nature of the liquid-vapor interface and its role in local heat and mass transport have been largely ignored. The vapor interface is rarely stationary. Interfacial waves may substantially augment the heat transfer rates throughout the layer. The present analysis treats stagnation point flow film boiling on a sphere immersed in a subcooled ...
Coupled modeling of subsurface multiphase fluid and heat flow, solute transport and chemical reactions can be used for the assessment of acid mine drainage remediation, mineral deposition, waste disposal sites, hydrothermal convection, contaminant transport, and groundwater quality. Here they present a numerical simulation model, TOUGHREACT, which considers non-isothermal multi-component chemical transport in both liquid and gas phases. A wide range of subsurface thermo-physical-chemical processes is considered. The model can be applied to one-, two- or three-dimensional porous and fractured media with physical and chemical heterogeneity. The model can accommodate any number of chemical species present in liquid, gas and solidphases. A variety of equilibrium chemical reactions is considered, such as aqueous complexation, gas dissolution/exsolution, cation exchange, and surface complexation. Mineral ...
Samarium cobaltite ceramic perovskites, with and without platinum particles dispersion, are possible candidates as electrode for electrochemical conversion of hydrocarbon and for intermediate temperature solid oxide fuel cells (ITSOFC). In this work, samarium cobaltites were synthesized by the combustion method using cobalt, and samarium nitrates as cation precursors and urea as fuel. For containing-platinum compositions Pt (II) acetyl acetonate was also employed as precursor. The effect of Sr on the phase formation and its electrical behavior is also studied. Specific surface area (BET), SEM-EDX, TEM and XRD analysis are used to characterize the powders obtained. Powders were pressed into pellets and sintered in air in the temperature range of 1200 -1400 C. Electrical impedance spectroscopy studies (EIS) are performed on sintered samples. The as-prepared powders showed an amorphous structure and by TEM a very small particle size ...
Red mud is a solid waste produced in the process of alumina extraction from bauxite. In this paper, recovery iron from Bayer red mud was studied with direct reduction roasting process followed by magnetic separation, and then building materials were prepared from alumosilicate residues. After analysis of chemical composition and crystalline phase, the effects of different parameters on recovery efficiency of iron were carried out. The optimum reaction parameters were proposed as the following: ratio of carbon powder: red mud at 18:100, ratio of additives: red mud at 6:100, roasting at 1300 deg. C for 110 min. With these optimum parameters, total content of iron in concentrated materials was 88.77%, metallization ratio of 97.69% and recovery ratio of 81.40%. Then brick specimens were prepared with alumosilicate residues and hydrated lime. Mean compressive strength of specimens was 24.10 MPa. It was indicated that main mineral ...
In nuclear fuel, in approximately one quarter of the fissions, one of the two formed fission products is gaseous. These are mainly the noble gases xenon and krypton with isotopes of xenon contributing up to 90% of the product gases. These noble fission gases do not combine with other species, and have a low solubility in the normally used uranium oxide matrix. They can be dissolved in the fuel matrix or precipitate in nanometer-sized bubbles within the fuel grain, in micrometer-sized bubbles at the grain boundaries, and a fraction also precipitates in fuel pores, coming from fuel fabrication. A fraction of the gas can also be released into the plenum of the fuel rod. With increasing fission, and therefore burn-up, the ceramic fuel material experiences a transformation of its structure in the 'cooler' rim region of the fuel. A subdivision occurs of the original fuel grains of few microns size into thousands of small grains of sub-micron sizes. Additionally, larger ...
A solid electrolyte cell comprises an alkali metal anode, e.g. lithium, a halogen-containing organic polymer cathode and a solid elecrolyte between the anode and the cathode. The cathode comprises iodine-containing vacuum-cyclised polyacrylonitrile, and the solid electrolyte is preferably lithium iodide and halogen-free vacuum-cyclised polyacrylonitrile. This patent also discloses the use of isotactic polyacrylonitrile, a method of making a cathode comprising iodine-containing vacuum-cyclised polyacrylonitrile, and novel methods of making the solid elecrolyte cells described.
The anaerobic biogasification of organic wastes generates two useful products: a medium-Btu fuel gas and a compost-quality organic residue. Although commercial-scale digestion systems are used to treat municipal sewage wastes, the disposal of solid organic wastes, including municipal solid wastes (MSW), requires a more cost-efficient process. Modern biogasification systems employ high-rate, high-solids fermentation methods to improve process efficiency and reduce capital costs. The design criteria and development stages are discussed. These systems are also compared with conventional low-solids fermentation technology.
Magnetite nanoparticles with high self-heating capacity and low toxicity characteristics are a promising candidate for cancer hyperthermia treatment. In order to achieve minimum dosage to a patient, magnetic nanoparticles with high heating capacity are needed. In addition, the influence of physiological factors on the heat capacity of a material should be investigated in order to determine the feasibility. In this study, magnetite nanoparticles coated with lauric acid were prepared by co-precipitation of Fe{sup 3+}:Fe{sup 2+} in a ratio of 2:1, 5:3, 3:2, and 4:3, and the pH was controlled using NaOH. Structural and magnetization characterization by means of X-ray diffractometry (XRD) and a superconducting quantum interference device (SQUID) revealed that the main species was Fe{sub 3}O{sub 4} and further showed that most of the nanoparticles exhibited superparamagnetic properties. All of the magnetic nanoparticles showed a specific absorption rate (SAR) increase that was linear with ...
Magnetic excitation in coupled multispin system is studied theoretically focusing on Cu_2Fe_2Ge_4O_1_3 and Cu_2CdB_2O_6 as typical examples of such system. These compounds consist of spin dimer and spin monomer parts and show an antiferromagnetic phase transition at low temperatures due to the spin monomer part. A multispin containing a spin dimer and spin monomers is treated as a basis unit. The multispin forms a spin multiplet and its energy levels are separated into high and low regions reflecting the characteristic energies of the dimer and monomer parts. We regard the system as interacting multispins and apply an extended Holstein-Primakoff theory by introducing bosons for each energy level of a spin multiplet. In the low-energy region, the obtained magnon dispersion and dynamical spin correlation function agree quantitatively with experimental results of inelastic neutron scattering performed in Cu_2Fe_2Ge_4O_1_3. Analyzing dynamical spin ...
Three copper-based alloys, CDA 102 (oxygen-free, high-purity copper), CDA 613 (aluminum bronze), and CDA 715 (Cu-30Ni), are candidates for the fabrication of high-level radioactive-waste disposal containers. Waste will include spent fuel assemblies from reactors as well as borosilicate glass, and will be sent to the prospective repository site at Yucca Mountain in Nye County, Nevada. The decay of radionuclides will result in the generation of substantial heat and in fluxes of gamma radiation outside the containers. In this environment, container materials might degrade by atmospheric oxidation, general aqueous phase corrosion, localized corrosion (LC), and stress corrosion cracking (SCC). This volume is a critical survey of available data on pitting and crevice corrosion of the copper-based candidates. Pitting and crevice corrosion are two of the most common forms of LC of these materials. Data on the SCC of these alloys is surveyed in Volume 4. Pitting usually ...
This project has been concerned with the understanding of certain key physical and physical chemical properties of polymeric systems which are related to their use as working substances in mechanochemical systems. Since the crystal-liquid phase transition is involved in the process of interest, attention has been focused on this transition and on the properties of semi-crystalline polymers. Two kinds of behavior and properties have been studied in this program. One of these is concerned with melting-crystallization under an applied external force. Here the primary matters of concern are the equilibrium melting temperature-stress relations and the associated problem of crystallization kinetics under an applied external stress. The other area of study involves mechanical properties, with particular emphasis on the influence of the morphological and structural variables which describe the semi-crystalline state. We have taken advantage in this work of concurrent ...
This paper deals with the heat transfer characteristics of horizontal steam generators, particularly under natural circulation (decay heat removal) conditions on the primary side. Special emphasis is on the inherent features of horizontal steam generator behaviour. A mathematical model of the horizontal steam generator primary side is developed and qualitative results are obtained analytically. A computer code, called HSG, is developed to solve the model numerically, and its predictions are compared with experimental data. The code is employed to obtain for VVER 440 steam generators quantitative results concerning the dependence of primary-to-secondary heat transfer efficiency on the primary side flow rate, temperature and secondary level. It turns out that the depletion of the secondary inventory leads to an inherent limitation of the decay energy removal in VVER steam generators. The limitation arises as a consequence of the steam generator tube bundle geometry. ...
The liquid-liquid extraction behavior of short-lived molybdenum and tungsten isotopes from HCl and HNO{sub 3} as well as HF/HNO{sub 3} acid media was studied using the {alpha}-benzoinoxime/chloroform system. The goal of the present experiments was to find an extraction system with a high selectivity for the group 6 elements in the periodic table which is suitable for the study the solution chemistry of seaborgium (Z = 106). It was found that Mo and W are both effectively extracted using {alpha}-benzoinoxime as an extractant and the maximum extraction yield is 100% and 94% for Mo and W, respectively. Ions of MO{sub 2}{sup 2+} (M = Mo, W) exist in HCl between the concentration range of 0.1-3 M and can be extracted quantitatively into the organic phase. The decrease of extraction yields at lower or higher acid concentration is due to the formation of anionic species MO{sub 4}{sup 2-} or MO{sub 2}Cl{sub 3}{sup -}. The extraction behavior of Mo and ...
The liquid-liquid extraction behavior of short-lived molybdenum and tungsten isotopes from HCl and HNO_3 as well as HF/HNO_3 acid media was studied using the #alpha#-benzoinoxime/chloroform system. The goal of the present experiments was to find an extraction system with a high selectivity for the group 6 elements in the periodic table which is suitable for the study the solution chemistry of seaborgium (Z = 106). It was found that Mo and W are both effectively extracted using #alpha#-benzoinoxime as an extractant and the maximum extraction yield is 100% and 94% for Mo and W, respectively. Ions of MO_2"2"+ (M = Mo, W) exist in HCl between the concentration range of 0.1-3 M and can be extracted quantitatively into the organic phase. The decrease of extraction yields at lower or higher acid concentration is due to the formation of anionic species MO_4"2"- or MO_2Cl_3"-. The extraction behavior of Mo and W in HNO_3 solution is similar to that in ...
A simple and specific method has been developed for the simultaneous determination of the four major Cinchona alkaloids and their dihydroderivatives and pyridoxine hydrochloride (Vitamin B_6) by high-performance liquid chromatography (HPLC) with fluorescence detection (#lambda#_e_m=420 nm with #lambda#_e_x=330 nm). The chromatographic separation was performed on a Phenomenex Prodigy ODS column (5 #mu#m, 250 mmx3.2 mm i.d.), recommended for basic compounds, under isocratic reversed-phase conditions. The method allowed a good peak shape and an effective resolution of the tested compounds. The extraction of alkaloids from the Cinchona succirubra bark was carried out in mild and fast conditions (ambient temperature, 20 min) by ultrasonication. The procedure showed to be advantageous respect to a reference method, which involved Soxhlet extraction. The results were compared statistically by means of the Student's t-test and the variance ratio F-test; no significant ...
Sixty-three subjects, aged 6 months to 16 years, who were enrolled in a prospective, fully blinded, randomized parallel-group phase III clinical trial, received 0.1 mmol/kg doses of either Gd-BOPTA (n=29) or Gd-DTPA (n=34). The MR images were acquired before and within 10 min of contrast agent injection. The primary objective was to compare the difference from pre-dose to post-dose lesion visualization between Gd-BOPTA and Gd-DTPA. Lesion visualization was determined as the sum of individual scores for three criteria of lesion morphological characteristics (lesion border delineation, internal morphology, and contrast enhancement), each assessed qualitatively using 4-point scales. Quantitative evaluation compared changes in lesion-to-background (LBR) and contrast-to-noise (CNR) ratios and per cent enhancement. Monitoring for adverse events and evaluation of vital signs and laboratory values was performed. Pre-dose to post-dose changes in lesion ...
This study was designed to quantitate the dose resulting from lead exposure during the critical periods of brain development during gestation by determining: (1) if blood lead concentration in rat dams is affected by pregnancy status or duration of lead exposure, (2) if lead concentration in fetuses is associated with the duration of dam exposure, (3) the rates of lead absorption and elimination in pregnant and nonpregnant dams; and (4) the effect that prebreeding exposure on lead kinetics in the dam and upon fetus blood lead concentrations. The results of experiments in which the dams' drinking water contained 50 mg/L lead indicate blood lead levels (after normalizing by water consumption on a body weight basis) of pregnant rats are significantly higher than blood lead levels of non-pregnant rats. Statistical differences in blood lead levels were observed by day 15 of gestation and continue through day 20 of gestation. These blood lead differences are not due to ...
Immobilization of a model liquid organic pollutant, i.e. the 2-chloroaniline (2-CA), into a cement matrix using organoclays as pre-sorbent agents was investigated. Five cement-clay pastes were prepared with different nominal water-to-cement ratios (w/c=0.40, 0.25 and 0.15 wt/wt) and various amounts of waste (waste-to-cement o/c=0.20, 0.60 and 1.00 wt/wt); for comparison, a neat cement paste was also prepared. Dynamic leach tests were performed on solidified monoliths in order to assess the successful immobilization of the 2-CA. In monoliths at constant w/c ratio (0.40) the total amount of pollutant released increases with its initial content, and ranges from 15 to 35% with respect to it. By lowering w/c from 0.40 to 0.15 at constant o/c, the performances improved (<25% released). The microstructure of the hardened cement-clay pastes was characterized by quantitative X-ray diffraction (QXRD) and electronic microscopy (SEM-EDS) techniques; hydration degree was ...
Radioactive "3"1Si was used as a marker to study metal silicide formation. Activity profiles in the silicides were measured by a combination of ion beam sputtering, radioactivity counting and Rutherford backscattering of charged nuclear particles. It was found that the metal is the diffusing species during Co_2Si, Pt_2Si, NiSi and PtSi formation, while silicon diffuses during CrSi_2, TiSi_2 and ZrSi_2 formation. Silicon was also found to be the diffusing species during second phase formation of CoSi from Co_2Si. However, in this case it was established that the silicon diffuses by a grain boundary and/or interstitial mechanism. Both the metal and silicon diffuse during Ni_2Si and Pd_2Si formation. In an attempt to interpret complex radioactivity profiles a computer program, simulating various diffusion mechanisms during both first and second phase silicide formation, was written. A numerical approach was used whereby silicide growth occurs in ...
AFFF has fabricated the (U, Pu)O_2 mixed oxide fuels for PHWRs, BWRs, PFBRs and FBTRs. The quantitative dissolution of the fuel samples are required within time for accurate determination of uranium-plutonium in chemical quality control laboratory. This paper describes the use of microwave heating technique in quantitative dissolution of (U, Pu)O_2 MOX (from 0.4% to 44% PuO_2). (author)
... These assumptions are quantitatively investigated by calculating tie icldti\\e inportance of ... A modified lon-shore current model is used to study the ...
BackgroundDiscrepancies between the conclusions of different meta-analyses (quantitative syntheses of systematic reviews) are often ascribed to methodological differences. The objective...Full Text Available
A specific application of single photon emission tomography to the relative quantitation of the pituitary region is described together with the results obtained in 19 patients with pituitary adenoma...Full Text Available
Motivation: Automatic recognition of cell identities is critical for quantitative measurement, targeting and manipulation of cells of model animals at single-cell resolution. It has been...Full Text Available
Typing Workshop": [Introductions] [Intro, DNA Basics, and Historical Perspective] [DNA Extraction] [Validation and QA/QC] [DNA Quantitation] [PCR Amplification] [STR Loci and Kits]...
BACKGROUND: An approach to the study of the pharmacokinetics of drugs in the lung is to measure their concentrations in bronchial biopsy specimens. The main criticism of this technique is that bronchial...Full Text Available
This laboratory exercise demonstrates some basic principles in parasitology by using experimental studies of the relationship of Hymenolepis diminuta with its rodent host.
Abstract: The current financial crisis has now led most major central banks to rely on quantitative easing. The unique Japanese experience of quantitative easing is the only experience which enables us to judge this therapy's effectiveness and the timing of the exit strategy. In this paper, we provide a new empirical framework to examine the effectiveness of Japanese monetary policy during the ''lost'' decade and quantify the effect of quantitative easing on Japan's activity and prices. We combine advantages of Markov-switching VAR methodology with those of factor analysis to establish two major findings. First, we show that the decisive change in regime occurred in two steps: it crept out from late 1995 and established itself durably in February 1999. Second, we show for the first time th...
Absolute measurements of cerebral blood flow (CBF) are an important endpoint in studies of cerebral pathophysiology. Currently no accepted method exists for in vivo longitudinal...Full Text Available
OBJECTIVEEvaluate the qualitative and quantitative differences between moderated and unmoderated on-line social support groups focused on asthma.DESIGNA...Full Text Available
Computer-Aided Prediction of Chemical Ecotoxicity on the basis of Quantitative Structure-Activity Relationships with the Use of Physico-Chemical Descriptors, Including H-bond Parameters
AIM: To investigate the effects of gallbladder stones on motor functions of the gallbladder and the dynamics of bile flow in asymptomatic gallstone disease.METHODS: Quantitative hepatobiliary...Full Text Available
BackgroundSeveral fractal and non-fractal parameters have been considered for the quantitative assessment of the vascular architecture, using a variety of test specimens and of computational...Full Text Available
OBJECTIVE AND DESIGNThis study used qualitative and quantitative methods to examine the reasons primary care physicians and nurses offered for their inability to initiate guideline-concordant...Full Text Available
The concentration of apolipoproteins was measured by quantitative immunoelectrophoresis in rat serum, in the lipoprotein-free ultracentrifugal fraction (density greater than 1.21) of serum, and in renal...Full Text Available
In this model, without dark matter, the flat rotation curves of galaxies and the mass-to-light ratios of clusters of galaxies are described quantitatively. The hypothesis is that the agent of gravitational...Full Text Available
The quantitative measurement of carbon concentration-distance curves serves as fundamental prerequisite for the evaluation of rim zone properties connected with decarburisation processes in material science. This was shown in part 1 of the present work with two samples from through-hardenable rolling bearing steel 100Cr6 (SAE 52100) austenitised in different oxidising atmospheres by position dependent determination of hardness, residual stresses, and X-ray line broadening ({l_brace}211{r_brace} {alpha}'-Fe diffraction line). In practice, it is important to predict carbon concentration-distance curves under prevailing heat treatment conditions or to conclude conversely from profile measurements. Based on a refined kinetics model of a diffusion-controlled process, part 2 therefore presents a simulation tool developed by means of the finite element method (FEM). Apart from the concentration dependence of the diffusion coefficient, it also considers the ...
Given that fossil fuel fired power plants are among the largest and most concentrated producers of CO{sub 2} emissions, recovery and sequestration of CO{sub 2} from the flue gas of such plants has been identified as one of the primary means for reducing anthropogenic CO{sub 2} emissions. In this study, ALSTOM Power Inc. (ALSTOM) has investigated several coal fired power plant configurations designed to capture CO{sub 2} from effluent gas streams for use or sequestration. Burning fossil fuels in mixtures of oxygen and recirculated flue gas (made principally of CO{sub 2}) essentially eliminates the presence of atmospheric nitrogen in the flue gas. The resulting flue gas is comprised primarily of CO{sub 2}. Oxygen firing in utility scale Pulverized Coal (PC) fired boilers has been shown to be a more economical method for CO{sub 2} capture than amine scrubbing (Bozzuto, et al., 2001). Additionally, oxygen firing in Circulating Fluid Bed Boilers (CFB's) can be more economical than ...
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
Objective: To further delineate the clinicopathological and radiological features of solid pseudopapillary tumor (SPT) of the pancreas and summarize the surgical therapy strategy for this tumor. Methods:...Full Text Available
Solid-pseudopapillary tumor (SPT) is a rare neoplasm of the pancreas that usually occurs in young females. It is generally considered a low-grade malignant tumor that can remain asymptomatic for several...Full Text Available